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Sample records for solar para controle

  1. Solar Control design package

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Information used in the evaluation of design of Solar Control's solar heating and cooling system controller and the Solarstat is given. Some of the information includes system performance specifications, design data brochures, and detailed design drawings.

  2. Controlled reflectance solar cell

    SciTech Connect

    Dill, H.G.; Lillington, D.R.

    1989-06-13

    A solar cell is described comprising: A semiconductor body having a front layer of a first conductivity type and an adjacent back layer of a second conductivity type opposite of the first conductivity type. The front and back layers form front and back major surfaces, respectively the semiconductor body further having openings through the back major surface and back layer which form recesses extending to the front layer. The recesses having walls which are doped to the first conductivity type; a first electrical contact disposed in the recesses making electrical contact the first conductivity type layer; and a second electrical contact disposed on the back major surface making electrical contact to the second conductivity type layer.

  3. Solar Sail Control Actuator Concepts

    NASA Technical Reports Server (NTRS)

    Mangus, David; Heaton, Andy

    2004-01-01

    The thrust produced by a solar sail is a direct function of its attitude. Thus, solar sail thrust vector control is a key technology that must be developed for sailcraft to become a viable form of deep-space transportation. The solar sail community has been studying various sail Attitude Control System (ACS) actuator designs for near Earth orbit as well as deep space missions. These actuators include vanes, spreader bars, two-axis gimbals, floating/locking gimbals with wheels, and translating masses. This paper documents the various concepts and performs an assessment at the highest level. This paper will only compare the various ACS actuator concepts as they stand at the publication time. This is not an endorsement of any particular concept. As concepts mature, the assessments will change.

  4. Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

    NASA Technical Reports Server (NTRS)

    Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.; Lowther, S. E.; Lillehei, P. T.; Bryant, R. G.

    2012-01-01

    Tailoring the solar absorptivity (alpha(sub s)) and thermal emissivity (epsilon(sub T)) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The alpha(sub s) and epsilon(sub T) were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the alpha(sub s) and epsilon(sub T) by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  5. Optimal control studies of solar heating systems

    SciTech Connect

    Winn, C B

    1980-01-01

    In the past few years fuel prices have seen steady increases. Also, the supply of fuel has been on the decline. Because of these two problems there has been an increase in the number of solar heated buildings. Since conventional fuel prices are increasing and as a solar heating system represents a high capital cost it is desirable to obtain the maximum performance from a solar heating system. The control scheme that is used in a solar heated building has an effect on the performance of the solar system. The best control scheme possible would, of course, be desired. This report deals with the control problems of a solar heated building. The first of these problems is to control the inside temperature of the building and to minimize the fuel consumption. This problem applies to both solar and conventionally heated buildings. The second problem considered is to control the collector fluid flow to maximize the difference between the useful energy collected and the energy required to pump the fluid. The third problem is to control the enclosure temperature of a building which has two sources of heat, one solar and the other conventional.

  6. Simple control device senses solar position

    NASA Technical Reports Server (NTRS)

    Lonborg, J. O.; Randall, J. C.

    1965-01-01

    The amount of solar radiation incident on a specially prepared bimetallic strip is simply and reliably controlled by a light valve. This device is valuable for systems requiring temperature regulation.

  7. Parachute suspended solar pointing control system

    NASA Astrophysics Data System (ADS)

    Sakoda, G. T.; Fujimoto, R. J.; Shigemoto, J. M.; Windsor, R. M.

    A high altitude parachute suspended solar pointing control system has been developed and flight tested for use in the altitude range of 30 to 70 kilometers. This development provides an opportunity for extended solar observations at altitudes higher than that attainable by helium balloons. The new system utilizes the NASA high altitude cross parachute to slow the descent of a rocket launched payload allowing observations in the region of interest. Solar pointing is established by using solar sensors in conjunction with a servo controlled platform and cold gas thrusters for payload roll control. The inherent spin of the cross parachute is decoupled by a swivel joint attached to the parachute suspension lines. This paper describes the design, test and flight performance of the new system.

  8. Parachute-suspended solar pointing control system

    NASA Astrophysics Data System (ADS)

    Sakoda, G. T.; Fujimoto, R. J.; Shigemoto, J. M.; Windsor, R. M.

    1984-04-01

    A high altitude parachute suspended solar pointing control system has been developed and flight tested for use in the altitude range of 30 to 70 kilometers. This development provides an opportunity for extended solar observations at altitudes higher than that attainable by helium balloons. The new system utilizes the NASA high altitude cross parachute to slow the descent of a rocket launched payload allowing observations in the region of interest. Solar pointing is established by using solar sensors in conjunction with a servo controlled platform and cold gas thrusters for payload roll control. The inherent spin of the cross parachute is decoupled by a swivel joint attached to the parachute suspension lines. This paper describes the design, test and flight performance of the new system.

  9. Solar optical telescope primary mirror controller

    NASA Technical Reports Server (NTRS)

    Brown, R. J.; Liu, D.

    1980-01-01

    The development of a technique to control the articulated primary mirror (APM) of the solar optical telescope (SOT) is discussed. Program results indicate that a single, all digital controller has sufficient capability to totally handle the computational requirements for control of the SOT APM.

  10. Solar flares controlled by helicity conservation

    NASA Technical Reports Server (NTRS)

    Gliner, Erast B.; Osherovich, Vladimir A.

    1995-01-01

    The energy release in a class of solar flares is studied on the assumption that during burst events in highly conducting plasma the magnetic helicity of plasma is approximately conserved. The available energy release under a solar flare controlled by the helicity conservation is shown to be defined by the magnetic structure of the associated prominence. The approach throws light on some solar flare enigmas: the role of the associated prominence. The approach throws light on some solar flare enigmas: the role of the associated prominences; the discontinuation of the reconnection of magnetic lines long before the complete reconnection of participated fields occurs; the existence of quiet prominences which, in spite of their usual optical appearance, do not initiate any flare events; the small energy release under a solar flare in comparison with the stockpile of magnetic energy in surrounding fields. The predicted scale of the energy release is in a fair agreement with observations.

  11. The SolarTrak solar array tracking controller

    NASA Astrophysics Data System (ADS)

    Maish, A. B.

    1991-07-01

    Sandia National Laboratories has developed an advanced self-contained tracking control system for use with one- or two-axis tracking solar arrays. The SolarTrak system computes the sun's position based on the time and stored position data, and then controls two motors to point the tracker at the sun without using sun sensors. When used with a photovoltaic concentrator array, the system initially performs a self-alignment routine using array-generated current to locate the sun. The routine computes six numbers that are used during the normal operation to correct the array pointing for the tracker's installation misalignment. This enables the tracker to point accurately even with installation misalignments of up to several degrees. The SolarTrak system consists of a control board, which contains a Motorola 68HC11 microcontroller, a power supply board, motor-interface boards, and a hand-held user interface board, which contains a liquid-crystal display and an input keypad. This report contains a thorough discussion of the controller software and hardware, including control algorithms, parts lists and estimated costs (about $300 per system). The performance measured on two trackers is reviewed. Tracking accuracy was better than plus minus 0.1 degrees over a full day on one system. A thorough user's manual is included. Companies interested in licensing the technology should contact the Technology Transfer Division of Sandia National Laboratories.

  12. Solar energy control system. [temperature measurement

    NASA Technical Reports Server (NTRS)

    Currie, J. R. (Inventor)

    1981-01-01

    A solar energy control system for a hot air type solar energy heating system wherein thermocouples are arranged to sense the temperature of a solar collector, a space to be heated, and a top and bottom of a heat storage unit is disclosed. Pertinent thermocouples are differentially connected together, and these are employed to effect the operation of dampers, a fan, and an auxiliary heat source. In accomplishing this, the differential outputs from the thermocouples are amplified by a single amplifier by multiplexing techniques. Additionally, the amplifier is corrected as to offset by including as one multiplex channel a common reference signal.

  13. A Surface-Controlled Solar Cell

    NASA Technical Reports Server (NTRS)

    Daud, T.; Crotty, G. T.

    1987-01-01

    Open-circuit voltage and cell efficiency increased. Proposed technique for controlling recombination velocity on solar-cell surfaces provides cells of increased efficiency and open-circuit voltage. In present cells, uncontrolled surface recombination velocity degrades opencircuit voltage and efficiency. In cell using proposed technique, transparent conducting layer, insulated from cell contacts, biased to enable variable control of surface recombination velocity.

  14. Flexible Models for Solar Sail Control

    NASA Technical Reports Server (NTRS)

    Weaver Smith, Suzanne; Song, Haiping; Baker, John R.; Black, Jonathan; Muheim, Danniella M.

    2005-01-01

    Solar sails employ a unique form of propulsion, gaining momentum from incident and reflected photons. However, the momentum transferred by an individual photon is extremely small. Consequently, a solar sail must have an extremely large surface area and also be extremely light. The flexibility of the sail then must be considered when designing or evaluating control laws. In this paper, solar sail flexibility and its influence on control effectiveness is considered using idealized two-dimensional models to represent physical phenomena rather than a specific design. Differential equations of motion are derived for a distributed parameter model of a flexible solar sail idealized as a rotating central hub with two opposing flexible booms. This idealization is appropriate for solar sail designs in which the vibrational modes of the sail and supporting booms move together allowing the sail mass to be distributed along the booms in the idealized model. A reduced analytical model of the flexible response is considered. Linear feedback torque control is applied at the central hub. Two translational disturbances and a torque disturbance also act at the central hub representing the equivalent effect of deflecting sail shape about a reference line. Transient simulations explore different control designs and their effectiveness for controlling orientation, for reducing flexible motion and for disturbance rejection. A second model also is developed as a two-dimensional "pathfinder" model to calculate the effect of solar sail shape on the resultant thrust, in-plane force and torque at the hub. The analysis is then extended to larger models using the finite element method. The finite element modeling approach is verified by comparing results from a two-dimensional finite element model with those from the analytical model. The utility of the finite element modeling approach for this application is then illustrated through examples based on a full finite element model.

  15. Solar tracking control system Sun Chaser

    NASA Technical Reports Server (NTRS)

    Scott, D. R.; White, P. R.

    1978-01-01

    The solar tracking control system, Sun Chaser, a method of tracking the Sun in all types of weather conditions is described. The Sun Chaser follows the Sun from east to west in clear or cloudy weather, and resets itself to the east position after sundown in readiness for the next sunrise.

  16. Spaceborne hypertelescope controlled by solar sails

    NASA Astrophysics Data System (ADS)

    Lardière, O.; Labeyrie, A.

    2002-10-01

    Snapshot imaging of exoplanets seems feasible with multi-apertures interferometric arrays according the hypertelescope principle. A space hypertelescope can be formed from a vast constellation of ultra-light optical elements positioned by small solar sails along the large primary sphere. Our calculations show that 1 m2 of solar reflective surface is sufficient to control a mass of 1.3 kg in geo-stationary orbit. However, L2 orbits are preferable for hypertelescopes larger than 200m, in order to avoid tidal forces between elements and slow drift of the whole constellation. A 10kg-spacecraft is the heavier limit to have a reasonable solar sail size, but 1kg would be preferable. This mass constraint seems compatible with recent advances in MOEMS and ultra-light mirrors.

  17. Illumination control apparatus for compensating solar light

    NASA Technical Reports Server (NTRS)

    Owens, L. J. (Inventor)

    1978-01-01

    An illumination control apparatus is presented for supplementing light from solar radiation with light from an artificial light source to compensate for periods of insufficient levels of solar light. The apparatus maintains a desired illumination level within an interior space comprising an artificial light source connected to an electrical power source with a switch means for selectively energizing said light source. An actuator means for controlling the on-off operation of the switch means is connected to a light sensor which responses to the illumination level of the interior space. A limit switch carried adjacent to the actuator limits the movement of the actuator within a predetermined range so as to prevent further movement thereof during detection of erroneous illumination conditions.

  18. Solar tracking control system Sun Chaser

    NASA Technical Reports Server (NTRS)

    Scott, D. R.; White, P. R.

    1979-01-01

    The solar tracking control system (Sun Chaser) is believed to be an improved method of tracking the Sun in all types of weather conditions. The Sun Chaser will follow the Sun from east to west in clear or cloudy weather, and reset itself to the east position after sundown in readiness for the next sunrise. A description of the Sun Chaser hardware and its operation together with results is presented.

  19. Attitude control of large solar power satellites

    NASA Technical Reports Server (NTRS)

    Oglevie, R. E.

    1978-01-01

    Satellite power systems are a promising future source of electrical energy. However, the very large size solar power satellites (relative to contemporary spacecraft) requires investigation of the resulting attitude control problems and of appropriate control techniques. The principal effects of the large size are a great increase in sensitivity to gravity-gradient torques and a great reduction in structural bending frequencies with the attendant likelihood of undesirable control system interaction. A wide variety of control techniques are investigated to define approaches that minimize implementation penalties. These techniques include space-constructed momentum wheels, gravity-gradient stabilization, quasi-inertial free-drift modes, and various reaction control thruster types, some of which reduce the implementation penalties to a few percent of the spacecraft mass. The control system/structural dynamic interaction problem is found to have a tractable solution. Some of the results can be applied to other large space structure spacecraft.

  20. Solar Sail Attitude Control Performance Comparison

    NASA Technical Reports Server (NTRS)

    Bladt, Jeff J.; Lawrence, Dale A.

    2005-01-01

    Performance of two solar sail attitude control implementations is evaluated. One implementation employs four articulated reflective vanes located at the periphery of the sail assembly to generate control torque about all three axes. A second attitude control configuration uses mass on a gimbaled boom to alter the center-of-mass location relative to the center-of-pressure producing roll and pitch torque along with a pair of articulated control vanes for yaw control. Command generation algorithms employ linearized dynamics with a feedback inversion loop to map desired vehicle attitude control torque into vane and/or gimbal articulation angle commands. We investigate the impact on actuator deflection angle behavior due to variations in how the Jacobian matrix is incorporated into the feedback inversion loop. Additionally, we compare how well each implementation tracks a commanded thrust profile, which has been generated to follow an orbit trajectory from the sun-earth L1 point to a sub-L1 station.

  1. Solar Powered Automobile Interior Climate Control System

    NASA Technical Reports Server (NTRS)

    Howard, Richard T. (Inventor)

    2003-01-01

    There is provided a climate control system for a parked vehicle that includes a solar panel, thermostatic switch, fans, and thermoelectric coolers. The solar panel can serve as the sole source of electricity for the system. The system affords convenient installation and removal by including solar panels that are removably attached to the exterior of a vehicle. A connecting wire electrically connects the solar panels to a housing that is removably mounted to a partially opened window on the vehicle. The thermostatic switch, fans, and thermoelectric coolers are included within the housing. The thermostatic switch alternates the direction of the current flow through the thermoelectric coolers to selectively heat or cool the interior of the vehicle. The interior surface of the thermoelectric coolers are in contact with interior heat sinks that have air circulated across them by an interior fan. Similarly, the exterior surface of the thermoelectric coolers are in contact with exterior heat sinks that have air circulated across them by an exterior fan.

  2. Attitude Dynamics and Control of Solar Sails

    NASA Astrophysics Data System (ADS)

    Sperber, Evan

    Solar sails are space vehicles that rely on solar radiation pressure in order to generate forces for thrust and attitude control torques. They exhibit characteristics such as large moments of inertia, fragility of various system components, and long mission durations that make attitude control a particularly difficult engineering problem. Thrust vector control (TVC) is a family of sailcraft attitude control techniques that is on a short list of strategies thought to be suitable for the primary attitude control of solar sails. Every sailcraft TVC device functions by manipulating the relative locations of the composite mass center (cm) of the sailcraft and the center of pressure (cp) of at least one of its reflectors. Relative displacement of these two points results in body torques that can be used to steer the sailcraft. This dissertation presents a strategy for the large-angle reorientation of a sailcraft using TVC. Two forms of TVC, namely the panel and ballast mass translation methods are well represented in the literature, while rigorous studies regarding a third form, gimballed mass rotation, are conspicuously absent. The gimballed mass method is physically realized by placing a ballast mass, commonly the sailcraft's scientific payload, at the tip of a gimballed boom that has its base fixed at some point on the sailcraft. A TVC algorithm will then strategically manipulate the payload boom's gimbal angles, thereby changing the projection of the sailcraft cm in the plane of the sail. This research demonstrates effective three-axis attitude control of a model sailcraft using numerical simulation of its nonlinear equations of motion. The particular TVC algorithm developed herein involves two phases---the first phase selects appropriate gimbal rates with the objective that the sailcraft be placed in the neighborhood of its target orientation. It was discovered, however that concomitantly minimizing attitude error as well as residual body rate was not possible using

  3. Control Analysis of flexible Solar Sails

    NASA Technical Reports Server (NTRS)

    Thomas, Stephanie J.; Paluszek, Michael A.

    2005-01-01

    Future solar sail missions will require sails with dimensions on the order of 100 m to l km. At these sizes, given the gossamer nature of the sail supporting structures, flexible modes may be low enough to interact with the control system. This paper develops a practical analysis of the flexible interactions using state-space systems and modal data from standard finite element models of the sail sub- system. The modal data is combined with a rigid core bus to create a modal coordinate state-space plant, which can be analyzed for stability with a state-space controller. Results are presented for an 80 m sail for both collocated actuation and control by actuators mounted at the sail tips.

  4. Bidirectional control system for energy flow in solar powered flywheel

    NASA Technical Reports Server (NTRS)

    Nola, Frank J. (Inventor)

    1987-01-01

    An energy storage system for a spacecraft is provided which employs a solar powered flywheel arrangement including a motor/generator which, in different operating modes, drives the flywheel and is driven thereby. A control circuit, including a threshold comparator, senses the output of a solar energy converter, and when a threshold voltage is exceeded thereby indicating the availability of solar power for the spacecraft loads, activates a speed control loop including the motor/generator so as to accelerate the flywheel to a constant speed and thereby store mechanical energy, while also supplying energy from the solar converter to the loads. Under circumstances where solar energy is not available and thus the threshold voltage is not exceeded, the control circuit deactivates the speed control loop and activates a voltage control loop that provides for operation of the motor as a generator so that mechanical energy from the flywheel is converted into electrical energy for supply to the spacecraft loads.

  5. Solar powered actuator with continuously variable auxiliary power control

    NASA Technical Reports Server (NTRS)

    Nola, F. J. (Inventor)

    1984-01-01

    A solar powered system is disclosed in which a load such as a compressor is driven by a main induction motor powered by a solar array. An auxiliary motor shares the load with the solar powered motor in proportion to the amount of sunlight available, is provided with a power factor controller for controlling voltage applied to the auxiliary motor in accordance with the loading on that motor. In one embodiment, when sufficient power is available from the solar cell, the auxiliary motor is driven as a generator by excess power from the main motor so as to return electrical energy to the power company utility lines.

  6. Control Electronics for Solar/Flywheel Power Supply

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1986-01-01

    Control circuit automatically directs flow of electrical energy to and from motor with flywheel that constitutes storage element of solar-power system. When insolation is sufficient for charging, power is supplied by solar-cell array to load and motor. During periods of darkness, motor made to act as generator, drawing kinetic energy from flywheel and supplying it to load.

  7. Attitude Dynamics and Controls for Large Solar Sails

    NASA Astrophysics Data System (ADS)

    Fu, Bo

    This dissertation enriches our knowledge of attitude control methodologies that are suitable for solar sails, and in particularly large solar sails. In chapter 1, the fundamental physics of solar sails and existing solar sail attitude control methodologies are reviewed. In chapter 2, an attitude control methodology (Tip Displacement Method) that is suitable for large solar sail is presented. In the proposed method, the sail wing-boom attachment points are allowed to move, and under solar radiation pressure, the sail membrane sags into a curved profile. A mathematical model of this curved profile is built, and analytical solutions of solar radiation body torque based on the curved wing is derived. It is shown that this methodology along can generate enough body toque in all three body axis directions for attitude control of large solar sails. In chapter 3, the propose method is further investigated, and the effect of incident solar radiation direction on solar radiation pressure body torque generation is studied. The effect of sail shape is also studied a step further, mainly by relaxing previously made cylindrical assumption on the shape of the wing. Based on an optimization process, algorithms for determining the shape of the wing are given, and solar radiation body torques are developed for the shape of the wing. One finding is that for small tip displacements, the cylindrical sail wing model is sufficient in estimating the solar radiation body torque. In chapters 2 and 3, the analyses are carried out based on the assumption that the wing shape is of a generalized cylinder. In chapter 4 a theoretical basis is provided for this assumption. Using the mathematical model of the single wing for the proposed tip displacement attitude control strategy, in chapter 5 a whole square solar sail model is built, and the system controllability is studied for linearized system states. The system is found to be robust because of the many actuators used, and is controllable even

  8. A Low-Cost Electronic Solar Energy Control

    ERIC Educational Resources Information Center

    Blade, Richard A.; Small, Charles T.

    1978-01-01

    Describes the design of a low-cost electronic circuit to serve as a differential thermostat, to control the operation of a solar heating system. It uses inexpensive diodes for sensoring temperature, and a mechanical relay for a switch. (GA)

  9. Asteroid rotation control via a tethered solar sail

    NASA Astrophysics Data System (ADS)

    Gao, Youtao; Wu, Jingyun

    2016-12-01

    The rotation of asteroids causes difficulties in the exploration of asteroids or prevention of asteroids impact on the Earth. We propose to use a solar sail to control, i.e., slow down or stop the rotational motion of an asteroid. First, the dynamic model of a tethered solar sail in the rotating gravitational field of an asteroid is presented. An optimal control method is employed to determine the control law of the tethered solar sail. The optimal control problem is converted into a nonlinear programming problem with the Gauss pseudospectral method. Simulation results show that this method can effectively slow down or even stop the rotation of an asteroid. A solar sail of 105 m2 can stop the rotation of the asteroid Apophis in 1000 days.

  10. Active Control of Solar Array Dynamics During Spacecraft Maneuvers

    NASA Technical Reports Server (NTRS)

    Ross, Brant A.; Woo, Nelson; Kraft, Thomas G.; Blandino, Joseph R.

    2016-01-01

    Recent NASA mission plans require spacecraft to undergo potentially significant maneuvers (or dynamic loading events) with large solar arrays deployed. Therefore there is an increased need to understand and possibly control the nonlinear dynamics in the spacecraft system during such maneuvers. The development of a nonlinear controller is described. The utility of using a nonlinear controller to reduce forces and motion in a solar array wing during a loading event is demonstrated. The result is dramatic reductions in system forces and motion during a 10 second loading event. A motion curve derived from the simulation with the closed loop controller is used to obtain similar benefits with a simpler motion control approach.

  11. Solar control of the upper atmosphere of Triton

    NASA Technical Reports Server (NTRS)

    Lyons, James R.; Yung, Yuk L.; Allen, Mark

    1992-01-01

    If the upper atmosphere and ionosphere of Triton are controlled by precipitation of electrons from Neptune's magnetosphere as previously proposed, Triton could have the only ionosphere in the solar system not controlled by solar radiation. However, a new model of Triton's atmosphere, in which only solar radiation is present, predicts a large column of carbon atoms. With an assumed, but reasonable, rate of charge transfer between N2(+) and C, a peak C(+) abundance results that is close to the peak electron densities measured by Voyager in Triton's ionosphere. These results suggest that Triton's upper atmospheric chemistry may thus be solar-controlled. Measurement of key reaction rate constants, currently unknown or highly uncertain at Triton's low temperatures, would help to clarify the chemical and physical processes occurring in Triton's atmosphere.

  12. Solar wind control of Jupiter's hectometric radio emission

    NASA Technical Reports Server (NTRS)

    Barrow, C. H.; Desch, M. D.

    1989-01-01

    Radio, plasma, and magnetic field data obtained by Voyager 1 and Voyager 2 were used to examine the manner in which the Jovian hectometric radio emission (HOM) is controlled by the solar wind. Using the method of superposed epochs, it was found that the higher energy HOM is correlated with the IMF as well as with the solar wind density and pressure. However, unlike the Io-independent decametric radio emission (Non-Io DAM), the HOM displayed no correlation with the solar wind velocity, although this radio component appear to be also influenced by the IMF. The results suggest separate HOM amd Non-Io DAM sources.

  13. Wave Front Sensor for Solar Concentrator Control

    DTIC Science & Technology

    2009-10-01

    Hartmann in 1900 and was used for checking optical telescopes for aberrations . It was an array of holes in a plate placed in front of the mirror of...a solar application and shows the adjustment from lenslets to cylindrical mirrors on a thruster. Next, the paper details the analysis and...cylindrical mirrors as applied to the problem statement are discussed in Section IV. Section V presents the first algorithm developed and applied to the model

  14. Experiment Study on Fuzzy Vibration Control of Solar Panel

    NASA Astrophysics Data System (ADS)

    Li, Dongxu X.; Xu, Rui; Jiang, Jiangjian P.

    Some flexible appendages of spacecraft are cantilever plate structures, such as solar panels. These structures usually have very low damping ratios, high dimensional order, low modal frequencies and parameter uncertainties in dynamics. Their unwanted vibrations will be caused unavoidably, and harmful to the spacecraft. To solve this problem, the dynamic equations of the solar panel with piezoelectric patches are derived, and an accelerometer based fuzzy controller is designed. In order to verify the effectiveness of the vibration control algorithms, experiment research was conducted on a piezoelectric adaptive composite honeycomb cantilever panel. The experiment results demonstrate that the accelerometer-based fuzzy vibration control method can suppress the vibration of the solar panel effectively, the first bending mode damping ratio of the controlled system increase to 1.64%, and that is 3.56 times of the uncontrolled system.

  15. Development of a neural network heating controller for solar buildings.

    PubMed

    Argiriou, A A; Bellas-Velidis, I; Balaras, C A

    2000-09-01

    Artificial neural networks (ANN's) are more and more widely used in energy management processes. ANN's can be very useful in optimizing the energy demand of buildings, especially of those of high thermal inertia. These include the so-called solar buildings. For those buildings, a controller able to forecast not only the energy demand but also the weather conditions can lead to energy savings while maintaining thermal comfort. In this paper, such an ANN controller is proposed. It consists of a meteorological module, forecasting the ambient temperature and solar irradiance, the heating energy switch predictor module and the indoor temperature-defining module. The performance of the controller has been tested both experimentally and in a building thermal simulation environment. The results showed that the use of the proposed controller can lead to 7.5% annual energy savings in the case of a highly insulated passive solar test cell.

  16. VERSATILE TWO-AXIS OPEN-LOOP SOLAR TRACKER CONTROLLER*

    SciTech Connect

    Ward, Christina D; Maxey, L Curt; Evans III, Boyd Mccutchen; Lapsa, Melissa Voss

    2008-01-01

    A versatile single-board controller for two-axis solar tracking applications has been developed and tested on operating solar tracking systems with over two years of field experience. The operating experience gained from the two systems and associated modifications are discussed as representative examples of the practical issues associated with implementing a new two-axis solar tracker design. In this research, open and closed loop control methods were evaluated; however, only the open loop method met the 0.125 tracking accuracy requirement and the requirement to maintain pointing accuracy in hazy and scattered cloudy skies. The open loop algorithm was finally implemented in a microcontroller-based tracking system. Methods of applying this controller hardware to different tracker geometries and hardware are discussed along with the experience gained to date.

  17. Morphology control of the perovskite films for efficient solar cells.

    PubMed

    Zheng, Lingling; Zhang, Danfei; Ma, Yingzhuang; Lu, Zelin; Chen, Zhijian; Wang, Shufeng; Xiao, Lixin; Gong, Qihuang

    2015-06-21

    In the past two years, the power conversion efficiency (PCE) of organic-inorganic hybrid perovskite solar cells has significantly increased up to 20.1%. These state-of-the-art new devices surpass other third-generation solar cells to become the most promising rival to the silicon-based solar cells. Since the morphology of the perovskite film is one of the most crucial factors to affect the performance of the device, many approaches have been developed for its improvement. This review provides a systematical summary of the methods for morphology control. Introductions and discussions on the mechanisms and relevant hotspots are also given. Understanding the growth process of perovskite crystallites has great benefits for further efficiency improvement and enlightens us to exploit new technologies for large-scale, low-cost and high-performance perovskite solar cells.

  18. Attitude and Translation Control of a Solar Sail Vehicle

    NASA Technical Reports Server (NTRS)

    Singh, Gurkirpal

    2008-01-01

    A report discusses the ability to control the attitude and translation degrees-of-freedom of a solar sail vehicle by changing its center of gravity. A movement of the spacecraft s center of mass causes solar-pressure force to apply a torque to the vehicle. At the compact core of the solar-sail vehicle lies the spacecraft bus which is a large fraction of the total vehicle mass. In this concept, the bus is attached to the spacecraft by two single degree-of-freedom linear tracks. This allows relative movement of the bus in the sail plane. At the null position, the resulting solar pressure applies no torque to the vehicle. But any deviation of the bus from the null creates an offset between the spacecraft center of mass and center of solar radiation pressure, resulting in a solar-pressure torque on the vehicle which changes the vehicle attitude. Two of the three vehicle degrees of freedom can be actively controlled in this manner. The third, the roll about the sunline, requires a low-authority vane/propulsive subsystem. Translation control of the vehicle is achieved by directing the solar-pressure-induced force in the proper inertial direction. This requires attitude control. Attitude and translation degrees-of-freedom are therefore coupled. A guidance law is proposed, which allows the vehicle to stationkeep at an appropriate point on the inertially-rotating Sun-Earth line. Power requirements for moving the bus are minimal. Extensive software simulations have been performed to demonstrate the feasibility of this concept.

  19. BSSDATA - um programa otimizado para filtragem de dados em radioastronomia solar

    NASA Astrophysics Data System (ADS)

    Martinon, A. R. F.; Sawant, H. S.; Fernandes, F. C. R.; Stephany, S.; Preto, A. J.; Dobrowolski, K. M.

    2003-08-01

    A partir de 1998, entrou em operação regular no INPE, em São José dos Campos, o Brazilian Solar Spectroscope (BSS). O BSS é dedicado às observações de explosões solares decimétricas com alta resolução temporal e espectral, com a principal finalidade de investigar fenômenos associados com a liberação de energia dos "flares" solares. Entre os anos de 1999 e 2002, foram catalogadas, aproximadamente 340 explosões solares classificadas em 8 tipos distintos, de acordo com suas características morfológicas. Na análise detalhada de cada tipo, ou grupo, de explosões solares deve-se considerar a variação do fluxo do sol calmo ("background"), em função da freqüência e a variação temporal, além da complexidade das explosões e estruturas finas registradas superpostas ao fundo variável. Com o intuito de realizar tal análise foi desenvolvido o programa BSSData. Este programa, desenvolvido em linguagem C++, é constituído de várias ferramentas que auxiliam no tratamento e análise dos dados registrados pelo BSS. Neste trabalho iremos abordar as ferramentas referentes à filtragem do ruído de fundo. As rotinas do BSSData para filtragem de ruído foram testadas nos diversos grupos de explosões solares ("dots", "fibra", "lace", "patch", "spikes", "tipo III" e "zebra") alcançando um bom resultado na diminuição do ruído de fundo e obtendo, em conseqüência, dados onde o sinal torna-se mais homogêneo ressaltando as áreas onde existem explosões solares e tornando mais precisas as determinações dos parâmetros observacionais de cada explosão. Estes resultados serão apresentados e discutidos.

  20. Multichannel temperature controller for hot air solar house

    NASA Technical Reports Server (NTRS)

    Currie, J. R.

    1979-01-01

    This paper describes an electronic controller that is optimized to operate a hot air solar system. Thermal information is obtained from copper constantan thermocouples and a wall-type thermostat. The signals from the thermocouples are processed through a single amplifier using a multiplexing scheme. The multiplexing reduces the component count and automatically calibrates the thermocouple amplifier. The processed signals connect to some simple logic that selects one of the four operating modes. This simple, inexpensive, and reliable scheme is well suited to control hot air solar systems.

  1. PSO based PI controller design for a solar charger system.

    PubMed

    Yau, Her-Terng; Lin, Chih-Jer; Liang, Qin-Cheng

    2013-01-01

    Due to global energy crisis and severe environmental pollution, the photovoltaic (PV) system has become one of the most important renewable energy sources. Many previous studies on solar charger integrated system only focus on load charge control or switching Maximum Power Point Tracking (MPPT) and charge control modes. This study used two-stage system, which allows the overall portable solar energy charging system to implement MPPT and optimal charge control of Li-ion battery simultaneously. First, this study designs a DC/DC boost converter of solar power generation, which uses variable step size incremental conductance method (VSINC) to enable the solar cell to track the maximum power point at any time. The voltage was exported from the DC/DC boost converter to the DC/DC buck converter, so that the voltage dropped to proper voltage for charging the battery. The charging system uses constant current/constant voltage (CC/CV) method to charge the lithium battery. In order to obtain the optimum PI charge controller parameters, this study used intelligent algorithm to determine the optimum parameters. According to the simulation and experimental results, the control parameters resulted from PSO have better performance than genetic algorithms (GAs).

  2. Performance of solar collector arrays and collector controllers in the National Solar Data Network

    NASA Astrophysics Data System (ADS)

    Logee, T. L.; Kendall, P. W.

    1984-07-01

    The accumulated National Solar Data Network (NSDN) data has been analyzed with regard to collector and collector control performance. The collector data is presented in the ASHRAE format as efficiency vs. operating points, (Tinlet - Tambient)/insolation. Collector controls were analyzed by determining the losses caused by control problems common to the NSDN solar systems. This study of collectors and collector controls has several objectives which are: (1) to compare actual and predicted collector performance; (2) to determine which generic types of components performed well and which performed poorly; (3) to determine why predicted performance was not achieved in the field; (4) to determine the types and causes of failures; (5) to determine the reliability weaknesses; and (6) to determine whether there are any component integration problems.

  3. Supramolecular Approaches to Nanoscale Morphological Control in Organic Solar Cells.

    PubMed

    Haruk, Alexander M; Mativetsky, Jeffrey M

    2015-06-11

    Having recently surpassed 10% efficiency, solar cells based on organic molecules are poised to become a viable low-cost clean energy source with the added advantages of mechanical flexibility and light weight. The best-performing organic solar cells rely on a nanostructured active layer morphology consisting of a complex organization of electron donating and electron accepting molecules. Although much progress has been made in designing new donor and acceptor molecules, rational control over active layer morphology remains a central challenge. Long-term device stability is another important consideration that needs to be addressed. This review highlights supramolecular strategies for generating highly stable nanostructured organic photovoltaic active materials by design.

  4. Optical tools and techniques for aligning solar payloads with the SPARCS control system. [Solar Pointing Aerobee Rocket Control System

    NASA Technical Reports Server (NTRS)

    Thomas, N. L.; Chisel, D. M.

    1976-01-01

    The success of a rocket-borne experiment depends not only on the pointing of the attitude control system, but on the alignment of the attitude control system to the payload. To ensure proper alignment, special optical tools and alignment techniques are required. Those that were used in the SPARCS program are described and discussed herein. These tools include theodolites, autocollimators, a 38-cm diameter solar simulator, a high-performance 1-m heliostat to provide a stable solar source during the integration of the rocket payload, a portable 75-cm sun tracker for use at the launch site, and an innovation called the Solar Alignment Prism. Using the real sun as the primary reference under field conditions, the Solar Alignment Prism facilitates the coalignment of the attitude sun sensor with the payload. The alignment techniques were developed to ensure the precise alignment of the solar payloads to the SPARCS attitude sensors during payload integration and to verify the required alignment under field conditions just prior to launch.

  5. Electronic system for high power load control. [solar arrays

    NASA Technical Reports Server (NTRS)

    Miller, E. L. (Inventor)

    1980-01-01

    Parallel current paths are divided into two groups, with control devices in the current paths of one group each having a current limiting resistor, and the control devices in the other group each having no limiting resistor, so that when the control devices of the second group are turned fully on, a short circuit is achieved by the arrangement of parallel current paths. Separate but coordinated control signals are provided to turn on the control devices of the first group and increase their conduction toward saturation as a function of control input, and when fully on, or shortly before, to turn on the control devices of the second group and increase their conduction toward saturation as a function of the control input as that input continues to increase. Electronic means may be used to generate signals. The system may be used for 1-V characteristic measurements of solar arrays as well as for other load control purposes.

  6. Thermal control of the solar electric propulsion stage

    NASA Technical Reports Server (NTRS)

    Ruttner, L. E.

    1973-01-01

    The thermal control requirements consist of functional requirements related to the various mission phase natural environments, operational requirements of induced power loadings by the solar electric propulsion stage subsystems, and design temperature limits for performance and reliability. The design approach utilizes passive thermal control techniques combining insulation, surface coatings, and sunshields with thermostatically controlled louvers. Heaters are used to regulate certain temperatures for extreme conditions. Details regarding the thruster array thermal control design are discussed, giving attention to the parameters used in the mathematical model, questions of conductive coupling, and thruster estimated power distribution.

  7. A deployable structure and solar array controls experiment for STEP

    NASA Technical Reports Server (NTRS)

    Nishimoto, T. S.

    1984-01-01

    A candidate configuration for a controls experiment on the Space Technology Experiments Platform (STEP) is described. The elements of the experiment are the mast, the solar array, and an articulation module between the two. The characteristic dimensions are very compatible for integration on a pallet such a STEP's proposed configuration. The controls' objective would be the measurement of orbiter interaction as well as the system identification of the appendages. The flight experiment configuration would also provide a test bed for various active vibration controls concepts. The instrumentation being considered would measure accelerations, strains, displacements, and temperatures. The deployable mast has eight elements defining a structural bay. Uniaxial measurements would be required to define loads at a cross section of the structure. Displacements due to thermal distortion of the mast and the local state of the solar concentrator may be measured by an optical ranging technique from the orbiter aft flight deck.

  8. Adaptive control for solar energy based DC microgrid system development

    NASA Astrophysics Data System (ADS)

    Zhang, Qinhao

    During the upgrading of current electric power grid, it is expected to develop smarter, more robust and more reliable power systems integrated with distributed generations. To realize these objectives, traditional control techniques are no longer effective in either stabilizing systems or delivering optimal and robust performances. Therefore, development of advanced control methods has received increasing attention in power engineering. This work addresses two specific problems in the control of solar panel based microgrid systems. First, a new control scheme is proposed for the microgrid systems to achieve optimal energy conversion ratio in the solar panels. The control system can optimize the efficiency of the maximum power point tracking (MPPT) algorithm by implementing two layers of adaptive control. Such a hierarchical control architecture has greatly improved the system performance, which is validated through both mathematical analysis and computer simulation. Second, in the development of the microgrid transmission system, the issues related to the tele-communication delay and constant power load (CPL)'s negative incremental impedance are investigated. A reference model based method is proposed for pole and zero placements that address the challenges of the time delay and CPL in closed-loop control. The effectiveness of the proposed modeling and control design methods are demonstrated in a simulation testbed. Practical aspects of the proposed methods for general microgrid systems are also discussed.

  9. Solar Dynamic Power System Stability Analysis and Control

    NASA Technical Reports Server (NTRS)

    Momoh, James A.; Wang, Yanchun

    1996-01-01

    The objective of this research is to conduct dynamic analysis, control design, and control performance test of solar power system. Solar power system consists of generation system and distribution network system. A bench mark system is used in this research, which includes a generator with excitation system and governor, an ac/dc converter, six DDCU's and forty-eight loads. A detailed model is used for modeling generator. Excitation system is represented by a third order model. DDCU is represented by a seventh order system. The load is modeled by the combination of constant power and constant impedance. Eigen-analysis and eigen-sensitivity analysis are used for system dynamic analysis. The effects of excitation system, governor, ac/dc converter control, and the type of load on system stability are discussed. In order to improve system transient stability, nonlinear ac/dc converter control is introduced. The direct linearization method is used for control design. The dynamic analysis results show that these controls affect system stability in different ways. The parameter coordination of controllers are recommended based on the dynamic analysis. It is concluded from the present studies that system stability is improved by the coordination of control parameters and the nonlinear ac/dc converter control stabilize system oscillation caused by the load change and system fault efficiently.

  10. Solar Manuvering Spacecraft Guidance and Control System Applications

    NASA Astrophysics Data System (ADS)

    Nejat, Cyrus

    2010-05-01

    The purpose of this project is to discuss the time of a transfer trajectory by consideration of the Earth's shadow. The time of transfer trajectory of a sail spacecraft was determined by consideration of the Earth's shadow and it was compared with the results in a case where the Earth's shadow was not taken into account. The solar sail spacecraft was demonstrated to be oriented in such a way that the solar force applies in one appropriate direction. The mathematical concept and feature shape of solar sail spacecraft were proven as correct design approaches. The equations of motion that were developed in the project were proven in correct format for transfer trajectory approach by means of the purposed CN (Cyrus Nejat) Equations of Motion. Four important comments were discussed from the observed results. The problem statement was depened along with appropriate assumptions. The solar sail craft was defined appropriately. The equations of motion were determined in order to evaluate the transfer trajectory of solar sail spacecraft. In this case, the time of flight was determined for two cases: with Earth's shadow, and without Earth's shadow. The results showed that the time of fight with the Earth's shadow consideration is higher than the time of fight without the Earth's shadow, but it had close responses due to small amount of force from the solar radiation pressure. The future of this project should also apply the Moon's shadow in the problem statement and determine the shadow of the Earth as it can be seen in a cone zone. There are also appropriate control system devices that should be designed for attitude determination. It is also necessary to apply appropriate damper system, composite and smart materials to remedy vibration problems.

  11. Accuracy analysis of pointing control system of solar power station

    NASA Technical Reports Server (NTRS)

    Hung, J. C.; Peebles, P. Z., Jr.

    1978-01-01

    The first-phase effort concentrated on defining the minimum basic functions that the retrodirective array must perform, identifying circuits that are capable of satisfying the basic functions, and looking at some of the error sources in the system and how they affect accuracy. The initial effort also examined three methods for generating torques for mechanical antenna control, performed a rough analysis of the flexible body characteristics of the solar collector, and defined a control system configuration for mechanical pointing control of the array.

  12. Symmetries in the Optimal Control of Solar Sail Spacecraft

    NASA Astrophysics Data System (ADS)

    Kim, M.; Hall, C. D.

    2005-08-01

    The theory of optimal control is applied to obtain minimum-time trajectories for solar sail spacecraft for interplanetary missions. We consider the gravitational and solar radiation forces due to the Sun. The spacecraft is modelled as a flat sail of mass m and surface area A and is treated dynamically as a point mass. Coplanar circular orbits are assumed for the planets. We obtain optimal trajectories for several interrelated problem families and develop symmetry properties that can be used to simplify the solution-finding process. For the minimum-time planet rendezvous problem we identify different solution branches resulting in multiple solutions to the associated boundary value problem. We solve the optimal control problem via an indirect method using an efficient cascaded computational scheme. The global optimizer uses a technique called Adaptive Simulated Annealing. Newton and Quasi-Newton Methods perform the terminal fine tuning of the optimization parameters.

  13. Flexible Dynamics and Attitude Control of a Square Solar Sail

    NASA Astrophysics Data System (ADS)

    Choi, Mirue

    This thesis presents a comprehensive analysis of attitude and structural dynamics of a square solar sail. In particular, this research examines the use of corner-attached reflective vanes to control the attitude of the spacecraft. An introduction to known solar sail designs is given, then the mathematics involved in calculating solar radiation pressure forces are presented. A detailed derivation and implementation of the unconstrained nonlinear flexible structural dynamics with Finite Element Method (FEM) models are explored, with several sample simulations of published large deflection experiments used as verification measures. To simulate the inability of a thin membrane to resist compression, the sail membrane elements are augmented with a method that approximates the wrinkling and the slacking dynamics, which is followed by a simulation of another well-known experiment as a verification measure. Once the structural dynamics are established, the usage of the tip vanes is explored. Specifically, a control allocation problem formed by having two degrees of freedom for each tip vane is defined and an efficient solution to this problem is presented, allowing desired control torques to be converted to appropriate vane angles. A randomized testing mechanism is implemented to show the efficacy of this algorithm. The sail shadowing problem is explored as well, where a component of the spacecraft casts shadow upon the sail and prevents solar radiation pressure force from being produced. A method to calculate the region of shadow is presented, and two different shadowing examples are examined --- due to the spacecraft bus, and due to the sail itself. Combining all of the above, an attitude control simulation of the sail model is presented. A simple PD controller combined with the control allocation scheme is used to provide the control torque for the sail, with which the spacecraft must orient towards a number of pre-specified attitude targets. Several attitude

  14. Shape control of slack space reflectors using modulated solar pressure.

    PubMed

    Borggräfe, Andreas; Heiligers, Jeannette; Ceriotti, Matteo; McInnes, Colin R

    2015-07-08

    The static deflection profile of a large spin-stabilized space reflector because of solar radiation pressure acting on its surface is investigated. Such a spacecraft consists of a thin reflective circular film, which is deployed from a supporting hoop structure in an untensioned, slack manner. This paper investigates the use of a variable reflectivity distribution across the surface to control the solar pressure force and hence the deflected shape. In this first analysis, the film material is modelled as one-dimensional slack radial strings with no resistance to bending or transverse shear, which enables a semi-analytic derivation of the nominal deflection profile. An inverse method is then used to find the reflectivity distribution that generates a specific, for example, parabolic deflection shape of the strings. Applying these results to a parabolic reflector, short focal distances can be obtained when large slack lengths of the film are employed. The development of such optically controlled reflector films enables future key mission applications such as solar power collection, radio-frequency antennae and optical telescopes.

  15. Shape control of slack space reflectors using modulated solar pressure

    PubMed Central

    Borggräfe, Andreas; Heiligers, Jeannette; Ceriotti, Matteo; McInnes, Colin R.

    2015-01-01

    The static deflection profile of a large spin-stabilized space reflector because of solar radiation pressure acting on its surface is investigated. Such a spacecraft consists of a thin reflective circular film, which is deployed from a supporting hoop structure in an untensioned, slack manner. This paper investigates the use of a variable reflectivity distribution across the surface to control the solar pressure force and hence the deflected shape. In this first analysis, the film material is modelled as one-dimensional slack radial strings with no resistance to bending or transverse shear, which enables a semi-analytic derivation of the nominal deflection profile. An inverse method is then used to find the reflectivity distribution that generates a specific, for example, parabolic deflection shape of the strings. Applying these results to a parabolic reflector, short focal distances can be obtained when large slack lengths of the film are employed. The development of such optically controlled reflector films enables future key mission applications such as solar power collection, radio-frequency antennae and optical telescopes. PMID:26345083

  16. Installation package for integrated programmable electronic controller and hydronic subsystem - solar heating and cooling

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A description is given of the Installation, Operation, and Maintenance Manual and information on the power panel and programmable microprocessor, a hydronic solar pump system and a hydronic heating hot water pumping system. These systems are integrated into various configurations for usages in solar energy management, control and monitoring, lighting control, data logging and other solar related applications.

  17. Supramolecular Approaches to Nanoscale Morphological Control in Organic Solar Cells

    PubMed Central

    Haruk, Alexander M.; Mativetsky, Jeffrey M.

    2015-01-01

    Having recently surpassed 10% efficiency, solar cells based on organic molecules are poised to become a viable low-cost clean energy source with the added advantages of mechanical flexibility and light weight. The best-performing organic solar cells rely on a nanostructured active layer morphology consisting of a complex organization of electron donating and electron accepting molecules. Although much progress has been made in designing new donor and acceptor molecules, rational control over active layer morphology remains a central challenge. Long-term device stability is another important consideration that needs to be addressed. This review highlights supramolecular strategies for generating highly stable nanostructured organic photovoltaic active materials by design. PMID:26110382

  18. Temperature control in a solar collector field using Filtered Dynamic Matrix Control.

    PubMed

    Lima, Daniel Martins; Normey-Rico, Julio Elias; Santos, Tito Luís Maia

    2016-05-01

    This paper presents the output temperature control of a solar collector field of a desalinization plant using the Filtered Dynamic Matrix Control (FDMC). The FDMC is a modified controller based on the Dynamic Matrix Control (DMC), a predictive control strategy widely used in industry. In the FDMC, a filter is used in the prediction error, which allows the modification of the robustness and disturbance rejection characteristics of the original algorithm. The implementation and tuning of the FDMC are simple and maintain the advantages of DMC. Several simulation results using a validated model of the solar plant are presented considering different scenarios. The results are also compared to nonlinear control techniques, showing that FDMC, if properly tuned, can yield similar results to more complex control algorithms.

  19. Which Solar and Geomagnetic Drivers Control Earth's Upper Atmosphere Thermostat?

    NASA Astrophysics Data System (ADS)

    Knipp, D.; Mlynczak, M. G.; McGranaghan, R. M.; Kilcommons, L. M.

    2015-12-01

    Nitric Oxide (NO) is a trace component of Earth's upper atmosphere that allows Earth's thermosphere to cool in response to energy input from solar extreme ultraviolet (EUV) photons and geomagnetic activity. When created and excited, NO molecules provide a natural thermostat via infrared radiative emissions [Kockarts, 1980]. A record of this cooling over the last 13 years has been provided by Mlynczak et al. [2014]. Nitric Oxide emissions in concert with EUV photons, auroral particles, and neutral thermosphere circulation determine if geomagnetic storms will deliver a sudden powerful upheaval of Earth's upper atmosphere or a damped event. In this talk I will review recent findings about the forecastability of solar and magnetospheric control of this important thermospheric trace constituent. In particular, I will discuss the role of pseudo-streamers and helmet streamers in the solar wind, and the possible role of magnetic cloud orientation, in determining the extent of thermospheric NO storm response. Anticipating the thermospheric NO response to geomagnetic storms is a next step in improving satellite drag forecasting.

  20. Instrument Control Unit for the EPD on board Solar Orbiter

    NASA Astrophysics Data System (ADS)

    Sánchez Prieto, S.; Prieto Mateo, M.; Rodríguez Polo; Gutiérrez Molina; Parra Espada, P.; da Silva Fariña, A.

    2013-05-01

    Undoubtedly, Solar Orbiter is the leading mission of the European Space Agency for studying the Sun in the current decade. Its elliptical orbit around the Sun, with a perihelion as low as 0.28 AU and with an increasing inclination of up to more than 25° with respect to the solar equator, makes it ideal for an in-situ environmental study. This study will provide the key to determine how does the Sun create and control the heliosphere, which is the main objective of this mission. One of the ten instruments that are part of the Solar Orbiter's payload is the Energetic Particle Detector (EPD). Its main objective is to measure the composition, timing and distribution functions of suprathermal and energetic particles. Scientific topics to be addressed include the sources, acceleration mechanisms, and transport processes of these particles. EPD is composed of four sensors (STEIN, EPT, HET and SIS), distributed along the spacecraft, and an Instrument Control Unit or ICU. The sensors are able to measure electrons in the energy range from 0.002 to 20 MeV, protons from 0.003 to 100 MeV and nucleons of He to Fe in the range of 0.008 to 200 MeV/n. The ICU is the sole interface with the spacecraft, providing control, communication and data processing to the sensors. Due to the strong reliability requirements associated to the ICU, special care has been taken in the hardware, software and mechanical designs. In this work the development status of the ICU, together with its hardware and software architectures, design decisions and tools are presented.

  1. Quality control and estimation of global solar radiation in China

    SciTech Connect

    Tang, Wenjun; He, Jie; Yang, Kun; Qin, Jun

    2010-03-15

    Measurements of surface radiation in China are too sparse to meet demand for scientific research and engineering applications. Moreover, the radiation data often include erroneous and questionable values though preliminary quality-check has been done before the data release. Therefore, quality control of radiation data is often a prerequisite for using these data. In this study, a set of quality-check procedures were implemented to control the quality of the solar radiation measurements at 97 stations in China. A hybrid model for estimating global solar radiation was then evaluated against the controlled data. The results show that the model can estimate the global radiation with accuracy of MBE less than 1.5 MJ m{sup -2} and RMSE less than 2.8 MJ m{sup -2} for daily radiation and RMSE less than 2.0 MJ m{sup -2} for monthly-mean daily radiation at individual stations over most of China except at a few stations where unsatisfactory estimates were possibly caused by severe air pollution or too dense clouds. The MBE averaged over all stations are about 0.7 MJ m{sup -2} and RMSE about 2.0 MJ m{sup -2} for daily radiation and RMSE about 1.3 MJ m{sup -2} for monthly-mean daily radiation. Finally, this model was used to fill data gaps and to expand solar radiation data set using routine meteorological station data in China. This data set would substantially contribute to some radiation-related scientific studies and engineering applications in China. (author)

  2. Controlling Attitude of a Solar-Sail Spacecraft Using Vanes

    NASA Technical Reports Server (NTRS)

    Mettler, Edward; Acikmese, Ahmet; Ploen, Scott

    2006-01-01

    A paper discusses a concept for controlling the attitude and thrust vector of a three-axis stabilized Solar Sail spacecraft using only four single degree-of-freedom articulated spar-tip vanes. The vanes, at the corners of the sail, would be turned to commanded angles about the diagonals of the square sail. Commands would be generated by an adaptive controller that would track a given trajectory while rejecting effects of such disturbance torques as those attributable to offsets between the center of pressure on the sail and the center of mass. The controller would include a standard proportional + derivative part, a feedforward part, and a dynamic component that would act like a generalized integrator. The controller would globally track reference signals, and in the presence of such control-actuator constraints as saturation and delay, the controller would utilize strategies to cancel or reduce their effects. The control scheme would be embodied in a robust, nonlinear algorithm that would allocate torques among the vanes, always finding a stable solution arbitrarily close to the global optimum solution of the control effort allocation problem. The solution would include an acceptably small angle, slow limit-cycle oscillation of the vanes, while providing overall thrust vector pointing stability and performance.

  3. Evaluation of steam and soil solarization for Meloidogyne arenaria control in Florida floriculture crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Steam and soil solarization were investigated for control of the root-knot nematode Meloidogyne arenaria in two years of field trials on a commercial flower farm in Florida. The objective was to determine if pre-plant steam treatments in combination with solarization, or solarization alone effective...

  4. Solar energy controlled-environment agriculture in the United States and in Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Luft, W.; Froechtenigt, J.

    1981-11-01

    Greenhouse designs proposed for use in hot climates to reduce the temperature by essentially passive means are illustrated. The project plans of the SOLERAS, solar powered, controlled environment agriculture are outlined. The water desalination technology being evaluated is reverse osmosis. The solar collection technologies include flat plate thermal collectors, solar ponds, photovoltaics and wind turbines.

  5. Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices

    NASA Technical Reports Server (NTRS)

    Munday, Jeremy

    2016-01-01

    Solar sails offer an opportunity for a CubeSatscale, propellant-free spacecraft technology that enables long-term and long-distance missions not possible with traditional methods. Solar sails operate using the transfer of linear momentum from photons of sunlight reflected from the surface of the sail. To propel the spacecraft, no mechanically moving parts, thrusters, or propellant are needed. However, attitude control, or orientation, is still performed using traditional methods involving reaction wheels and propellant ejection, which severely limit mission lifetime. For example, the current state of the art solutions employed by upcoming missions couple solar sails with a state of the art propellant ejection gas system. Here, the use of the gas thruster has limited the lifetime of the mission. To solve the limited mission lifetime problem, the Propellantless Attitude Control of Solar Sail Technology Utilizing Reflective Control Devices project team is working on propellantless attitude control using thin layers of material, an optical film, electrically switchable from transparent to reflective. The technology is based on a polymer-dispersed liquid crystal (PDLC), which allows this switch upon application of a voltage. This technology removes the need for propellant, which reduces weight and cost while improving performance and lifetime.

  6. Development and testing of the Solar Control Corporation modular controller and Solarstat subsystem

    NASA Technical Reports Server (NTRS)

    Hankins, J. D.

    1979-01-01

    Results of development work on an existing controller and solarstat subsystem for use with solar heating and cooling systems are presented. The deliverable end items, program objectives, and how they were accomplished are described. It is shown that the products developed are marketable and suitable for public use.

  7. Using Solar Radiation Pressure to Control L2 Orbits

    NASA Technical Reports Server (NTRS)

    Tene, Noam; Richon, Karen; Folta, David

    1998-01-01

    The main perturbations at the Sun-Earth Lagrange points L1 and L2 are from solar radiation pressure (SRP), the Moon and the planets. Traditional approaches to trajectory design for Lagrange-point orbits use maneuvers every few months to correct for these perturbations. The gravitational effects of the Moon and the planets are small and periodic. However, they cannot be neglected because small perturbations in the direction of the unstable eigenvector are enough to cause exponential growth within a few months. The main effect of a constant SRP is to shift the center of the orbit by a small distance. For spacecraft with large sun-shields like the Microwave Anisotropy Probe (MAP) and the Next Generation Space Telescope (NGST), the SRP effect is larger than all other perturbations and depends mostly on spacecraft attitude. Small variations in the spacecraft attitude are large enough to excite or control the exponential eigenvector. A closed-loop linear controller based on the SRP variations would eliminate one of the largest errors to the orbit and provide a continuous acceleration for use in controlling other disturbances. It is possible to design reference trajectories that account for the periodic lunar and planetary perturbations and still satisfy mission requirements. When such trajectories are used the acceleration required to control the unstable eigenvector is well within the capabilities of a continuous linear controller. Initial estimates show that by using attitude control it should be possible to minimize and even eliminate thruster maneuvers for station keeping.

  8. Phase control system concepts and simulations. [solar power satellite system

    NASA Technical Reports Server (NTRS)

    Lindsay, V. C.

    1980-01-01

    A phase control system concept for a solar power satellite is proposed which partitions the system into three major levels. The first level of phase control consists of a reference phase distribution system implemented in the form of phase distribution tree structure. The major purpose of the tree structure is to electronically compensate for the phase shift due to the transition path lengths from the center of the spacetenna to each phase control center located in each subarray. In the reference system, this is accomplished using the master slave returnable timing system technique. The second level of phase control consists of the beam steering and microwave power generating system which houses the power transponders. This transponder consists of a set of phase conjugation multipliers driven by the reference phase distribution system output and the output of a pilot spread spectrum receiver which accepts the received pilot via a diplexer connected to a separate receive horn or the subarray itself. The output of the phase conjugation circuits serve as inputs to the third level of the phase control system. The third level of phase control is associated with maintaining an equal and constant phase shift through the microwave power amplifier devices while minimizing the associated phase noise effects on the generated power beam. This is accomplished by providing a phase locked loop around each high power amplifier.

  9. Solar Dynamics Observatory Guidance, Navigation, and Control System Overview

    NASA Technical Reports Server (NTRS)

    Morgenstern, Wendy M.; Bourkland, Kristin L.; Hsu, Oscar C.; Liu, Kuo-Chia; Mason, Paul A. C.; O'Donnell, James R., Jr.; Russo, Angela M.; Starin, Scott R.; Vess, Melissa F.

    2011-01-01

    The Solar Dynamics Observatory (SDO) was designed and built at the Goddard Space Flight Center, launched from Cape Canaveral on February 11, 2010, and reached its final geosynchronous science orbit on March 16, 2010. The purpose of SDO is to observe the Sun and continuously relay data to a dedicated ground station. SDO remains Sun-pointing throughout most of its mission for the instruments to take measurements of the Sun. The SDO attitude control system (ACS) is a single-fault tolerant design. Its fully redundant attitude sensor complement includes sixteen coarse Sun sensors (CSSs), a digital Sun sensor (DSS), three two-axis inertial reference units (IRUs), and two star trackers (STs). The ACS also makes use of the four guide telescopes included as a part of one of the science instruments. Attitude actuation is performed using four reaction wheels assemblies (RWAs) and eight thrusters, with a single main engine used to provide velocity-change thrust for orbit raising. The attitude control software has five nominal control modes, three wheel-based modes and two thruster-based modes. A wheel-based Safehold running in the attitude control electronics box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. This paper details the final overall design of the SDO guidance, navigation, and control (GN&C) system and how it was used in practice during SDO launch, commissioning, and nominal operations. This overview will include the ACS control modes, attitude determination and sensor calibration, the high gain antenna (HGA) calibration, and jitter mitigation operation. The Solar Dynamics Observatory mission is part of the NASA Living With a Star program, which seeks to understand the changing Sun and its effects on the Solar System, life, and society. To this end, the SDO spacecraft carries three Sun

  10. Proximal Blade Twist Feedback Control for Heliogyro Solar Sails

    NASA Astrophysics Data System (ADS)

    Smith, Sarah Mitchell

    A heliogyro spacecraft is a specific type of solar sail that generates thrust from the reflection of solar photons. It consists of multiple long (200 to 600 meters), thin blades, similar to a helicopter. The heliogyro's blades remain in tension by spinning around the central hub of the spacecraft. The individual blades are pitched collectively or cyclically to produce the desired maneuver profile. The propellant-free heliogyro is a long-duration sustainable spacecraft whose maneuverability allows it to attain previously inaccessible orbits for traditional spacecraft. The blades are constructed from thin Mylar sheets, approximately 2.5 ?m thick, which have very little inherent damping making it necessary to include some other way of attenuating blade vibration caused by maneuvering. The most common approach is to incorporate damping through the root pitch actuator. However, due to the small root pitch control torques required, on the order of 2 ?Nm, compared to the large friction torques associated with a root pitch actuator, it is challenging to design a root control system that takes friction into account and can still add damping to the blade. The purpose of this research is to address the limitations of current control designs for a heliogyro spacecraft and to develop a physically realizable root pitch controller that effectively damps the torsional structural modes of a single heliogyro blade. Classical control theory in conjunction with impedance control techniques are used to design a position-source root pitch controller to dominate friction with high gains, wrapped with an outer loop that adds damping to the blade by sensing differential twist outboard of the blade root. First, modal parameter characterization experiments were performed on a small-scale heliogyro blade in a high vacuum chamber to determine a damping constant to be used in the membrane ladder finite element model of the blade. The experimental damping ratio of the lowest frequency torsional

  11. Um satélite brasileiro para observação do diâmetro solar

    NASA Astrophysics Data System (ADS)

    Emilio, M.; Leister, N. V.; Benevides Soares, P.; Teixeira, R.; Kuhn, J.

    2003-08-01

    Propomos uma missão espacial para medir a forma e o diâmetro solar com o objetivo de ajudar a determinar o potencial gravitacional do Sol e a sua rotação com precisão, testar modelos teóricos de variação de energia e pela primeira vez medir os modos g de oscilação. As observações serão obtidas através do instrumento denominado APT (Astrometric and Photometric Telescope) descrito por Kuhn(1983). A sensibilidade do instrumento é de 0,2 mas em 27 dias para as observações do diâmetro solar feitas a cada minuto. Esta é uma missão de três anos de duração e pode complementar as medidas que serão feitas pelo satélite PICARD (a ser lançado em 2007). Outros parâmetros físicos podem ser obtidos com as mesmas imagens o que certamente interessará à comunidade de física solar. Um primeiro contato foi realizado com a agência espacial brasileira que pretende lançar um satélite científico a cada dois anos.

  12. NEW HIGHER PERFORMANCE LOW COST SELECTIVE SOLAR RADIATION CONTROL COATINGS

    SciTech Connect

    Timothy Ellison; Buddie Dotter; David Tsu

    2003-10-28

    Energy Conversion Devices, Inc., ECD, has developed a new high-speed low-cost process for depositing high quality dielectric optical coatings--Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD). This process can deposit SiO{sub x} about 10 times faster than the state-of-the-art conventional technology, magnetron sputtering, at about 1/10th the cost. This process is also being optimized for depositing higher refractive index materials such as Si{sub 3}N{sub 4} and TiO{sub 2}. In this program ECD, in collaboration with Southwall Technologies, Inc. (STI), demonstrated that this process can be used to fabricate high performance low cost Selective Solar Radiation Control (SSRC) films for use in the automotive industry. These coatings were produced on thin (2 mil thick) PET substrates in ECD's pilot roll-to-roll pilot MPECVD deposition machine. Such film can be laminated with PVB in a vehicle's windows. This process can also be used to deposit the films directly onto the glass. Such highly selective films, with a visible transmission (T{sub vis}) of > 70% and a shading coefficient of < 60% can significantly reduce the heat entering a car from solar radiation. Consequently, passenger comfort is increased and the energy needed to operate air conditioning (a/c) systems is reduced; consequently smaller a/c systems can be employed resulting in improved vehicle fuel efficiency.

  13. Residential Solar Design Review: A Manual on Community Architectural Controls and Solar Energy Use.

    ERIC Educational Resources Information Center

    Jaffe, Martin; Erley, Duncan

    Presented are architectural design issues associated with solar energy use, and procedures for design review committees to consider in examining residential solar installation in light of existing aesthetic goals for their communities. Recommended design review criteria include the type of solar system being used and the ways in which the system…

  14. Cable tensioned membrane solar collector module with variable tension control

    DOEpatents

    Murphy, Lawrence M.

    1985-01-01

    Disclosed is a solar collector comprising a membrane for concentrating sunlight, a plurality of elongated structural members for suspending the membrane member thereon, and a plurality of control members for adjustably tensioning the membrane member, as well as for controlling a focus produced by the membrane members. Each control member is disposed at a different corresponding one of the plurality of structural members. The collector also comprises an elongated flexible tensioning member, which serves to stretch the membrane member and to thereafter hold it in tension, and a plurality of sleeve members, which serve to provide the membrane member with a desired surface contour during tensioning of the membrane member. The tensioning member is coupled to the structural members such that the tensioning member is adjustably tensioned through the structural members. The tensioning member is also coupled to the membrane member through the sleeve members such that the sleeve members uniformly and symmetrically stretch the membrane member upon applying tension to the tensioning member with the control members.

  15. Cable tensioned membrane solar collector module with variable tension control

    DOEpatents

    Murphy, L.M.

    1984-01-09

    Disclosed is a solar collector comprising a membrane member for concentrating sunlight, a plurality of elongated structural members for suspending the membrane member thereon, and a plurality of control members for adjustably tensioning the membrane member, as well as for controlling a focus produced by the membrane members. Each control member is disposed at a different corresponding one of the plurality of structural members. The collector also comprises an elongated flexible tensioning member, which serves to stretch the membrane member and to thereafter hold it in tension, and a plurality of sleeve members which serve to provide the membrane member with a desired surface contour during tensioning of the membrane member. The tensioning member is coupled to the structural members such that the tensioning member is adjustably tensioned through the structural members. The tensioning member is also coupled to the membrane member through the sleeve members such that the sleeve members uniformly and symmetrically stretch the membrane member upon applying tension to the tensioning member with the control members.

  16. Design and evaluation of a computer controlled solar collector simulator

    NASA Astrophysics Data System (ADS)

    Kotas, J. F.; Wood, B. D.

    1980-11-01

    A computer-controlled system has been developed to simulate the thermal processes of a flat-plate solar collector. The simulator is based on four water heaters of capacities of 1.5, 2.5, 5.0 and 5.0 kW providing a maximum design output of 14.0 kW which are controlled by a Nova 3 minicomputer, which also monitors temperatures in the fluid stream. Measurements have been obtained of the steady-state operating values and time constants of the individual heaters at different flow rates in order to utilize effectively their thermal outputs. Software was designed to control the heater system so the total thermal output closely approximates that of an actual heater array, utilizing steady-state or dynamic control modes. Simulation of the heat output of a previously tested collector has resulted in simulated values differing from actual output by a maximum of 3% under identical operating conditions, thus indicating that the simulator represents a viable alternative to the testing of a large field of collectors.

  17. Attitude Control System Design for the Solar Dynamics Observatory

    NASA Technical Reports Server (NTRS)

    Starin, Scott R.; Bourkland, Kristin L.; Kuo-Chia, Liu; Mason, Paul A. C.; Vess, Melissa F.; Andrews, Stephen F.; Morgenstern, Wendy M.

    2005-01-01

    The Solar Dynamics Observatory mission, part of the Living With a Star program, will place a geosynchronous satellite in orbit to observe the Sun and relay data to a dedicated ground station at all times. SDO remains Sun- pointing throughout most of its mission for the instruments to take measurements of the Sun. The SDO attitude control system is a single-fault tolerant design. Its fully redundant attitude sensor complement includes 16 coarse Sun sensors, a digital Sun sensor, 3 two-axis inertial reference units, 2 star trackers, and 4 guide telescopes. Attitude actuation is performed using 4 reaction wheels and 8 thrusters, and a single main engine nominally provides velocity-change thrust. The attitude control software has five nominal control modes-3 wheel-based modes and 2 thruster-based modes. A wheel-based Safehold running in the attitude control electronics box improves the robustness of the system as a whole. All six modes are designed on the same basic proportional-integral-derivative attitude error structure, with more robust modes setting their integral gains to zero. The paper details the mode designs and their uses.

  18. Cesium lead iodide solar cells controlled by annealing temperature.

    PubMed

    Kim, Yu Geun; Kim, Tae-Yoon; Oh, Jeong Hyeon; Choi, Kyoung Soon; Kim, Youn-Jea; Kim, Soo Young

    2017-02-22

    An inorganic lead halide perovskite film, CsPbI3, used as an absorber in perovskite solar cells (PSCs) was optimized by controlling the annealing temperature and the layer thickness. The CsPbI3 layer was synthesized by one-step coating of CsI mixed with PbI2 and a HI additive in N,N-dimethylformamide. The annealing temperature of the CsPbI3 film was varied from 80 to 120 °C for different durations and the thickness was controlled by changing the spin-coating rpm. After annealing the CsPbI3 layer at 100 °C under dark conditions for 10 min, a black phase of CsPbI3 was formed and the band gap was 1.69 eV. Most of the yellow spots disappeared, the surface coverage was almost 100%, and the rms roughness was minimized to 3.03 nm after annealing at 100 °C. The power conversion efficiency (PCE) of the CsPbI3 based PSC annealed at 100 °C was 4.88%. This high PCE value is attributed to the low yellow phase ratio, high surface coverage, low rms roughness, lower charge transport resistance, and lower charge accumulation. The loss ratio of the PCE of the CH3NH3PbIxCl3-x and CsPbI3 based PSCs after keeping in air was 47 and 26%, respectively, indicating that the stability of the CsPbI3 based PSC is better than that of the CH3NH3PbIxCl3-x based PSC. From these results, it is evident that CsPbI3 is a potential candidate for solar cell applications.

  19. Solar Thermal Upper Stage Liquid Hydrogen Pressure Control Testing

    NASA Technical Reports Server (NTRS)

    Moore, J. D.; Otto, J. M.; Cody, J. C.; Hastings, L. J.; Bryant, C. B.; Gautney, T. T.

    2015-01-01

    High-energy cryogenic propellant is an essential element in future space exploration programs. Therefore, NASA and its industrial partners are committed to an advanced development/technology program that will broaden the experience base for the entire cryogenic fluid management community. Furthermore, the high cost of microgravity experiments has motivated NASA to establish government/aerospace industry teams to aggressively explore combinations of ground testing and analytical modeling to the greatest extent possible, thereby benefitting both industry and government entities. One such team consisting of ManTech SRS, Inc., Edwards Air Force Base, and Marshall Space Flight Center (MSFC) was formed to pursue a technology project designed to demonstrate technology readiness for an SRS liquid hydrogen (LH2) in-space propellant management concept. The subject testing was cooperatively performed June 21-30, 2000, through a partially reimbursable Space Act Agreement between SRS, MSFC, and the Air Force Research Laboratory. The joint statement of work used to guide the technical activity is presented in appendix A. The key elements of the SRS concept consisted of an LH2 storage and supply system that used all of the vented H2 for solar engine thrusting, accommodated pressure control without a thermodynamic vent system (TVS), and minimized or eliminated the need for a capillary liquid acquisition device (LAD). The strategy was to balance the LH2 storage tank pressure control requirements with the engine thrusting requirements to selectively provide either liquid or vapor H2 at a controlled rate to a solar thermal engine in the low-gravity environment of space operations. The overall test objective was to verify that the proposed concept could enable simultaneous control of LH2 tank pressure and feed system flow to the thruster without necessitating a TVS and a capillary LAD. The primary program objectives were designed to demonstrate technology readiness of the SRS concept

  20. Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey. Final report

    SciTech Connect

    1981-03-01

    Solar heating and cooling of a 40,000 square foot manufacturing building, sales offices and the solar computer control center/display room are described. Information on system description, test data, major problems and resolutions, performance, operation and maintenance manual, manufacturer's literature and as-built drawings are provided also. The solar system is composed of 6000 square feet of Sunworks double glazed flat plate collectors, external above ground storage subsystem, controls, ARKLA absorption chiller, heat recovery and a cooling tower.

  1. Development of mass-producible line-focus tracking concentrating solar collectors. Category 2: Control systems

    NASA Astrophysics Data System (ADS)

    Hickman, T. E.

    1984-08-01

    The system design criteria and concept of a mass producible modular electronic control system for solar industrial process heating installations are discussed. The control system consists of: the master controller; the weather tower, including a solar tracking angle reference; and overtemperature switch, group control box, tracker/controller, and drive motor for each group of single axis tracking parabolic trough solar collectors. System automatic operation is outlined for unattended installations. The production approach and cost estimates, both based on a production rate of 5 million ft(2) of collector aperature per year, are discussed here. The potential for further development of the system is also presented.

  2. attitude control design for the solar polar orbit radio telesope

    NASA Astrophysics Data System (ADS)

    Gao, D.; Zheng, J.

    This paper studies the attitude dynamics and control of the Solar Polar Orbit Radio Telescope SPORT The SPORT which consists of one parent satellite and eight tethered satellites runs around the Sun in a polar orbit The parent satellite locates at the mass center of the constellation and tethered satellites which are tied with the parent satellite through a non-electric rope rotate around the parent satellite It is also supposed that the parent satellite and all tethered satellites are in a plane when the constellation works begin figure htbp centerline includegraphics width 3 85in height 2 38in 75271331 6a6eb71057 doc1 eps label fig1 end figure Fig 1 the SPORT constellation Firstly this paper gives the dynamic equations of the tethered satellite and the parent satellite From the dynamic characteristic of the tethered satellite we then find that the roll axis is coupled with the yaw axis The control torque of the roll axis can control the yaw angle But the control torque of the roll axis and pitch axis provided by the tether is very small it can not meet the accuracy requirement of the yaw angle In order to improve the attitude pointing accuracy of the tethered satellite a gradient pole is set in the negative orientation of the yaw axis The gradient pole can improve not only the attitude accuracy of roll angle and pitch angle but also that of the yaw angle indirectly As to the dynamic characteristic of the parent satellite the roll axis is coupled with the pitch axis due to the spinning angular velocity At the same

  3. Flex Dynamics Avoidance Control of the NEA Scout Solar Sail Spacecraft's Reaction Control System

    NASA Technical Reports Server (NTRS)

    Heaton Andrew; Stiltner, Brandon; Diedrich, Benjamin; Becker, Christopher; Orphee, Juan

    2017-01-01

    The Attitude Control System (ACS) is developed for a Near Earth Asteroid (NEA) Scout mission using a solar sail. The NEA-Scout spacecraft is a 6U cubesat with an 86 square-meter solar sail. NEA Scout will launch on Space Launch System (SLS) Exploration Mission 1 (EM-1), currently scheduled to launch in 2018. The spacecraft will rendezvous with a target asteroid after a two year journey, and will conduct science imagery. The solar sail spacecraft ACS consists of three major actuating subsystems: a Reaction Wheel (RW) control system, a Reaction Control System (RCS), and an Adjustable Mass Translator (AMT) system. The three subsystems allow for a wide range of spacecraft attitude control capabilities, needed for the different phases of the NEA-Scout mission. Because the sail is a flexible structure, care must be taken in designing a control system to avoid exciting the structural modes of the sail. This is especially true for the RCS, which uses pulse actuated, cold-gas jets to control the spacecraft's attitude. While the reaction wheels can be commanded smoothly, the RCS jets are simple on-off actuators. Long duration firing of the RCS jets - firings greater than one second - can be thought of as step inputs to the spacecraft's torque. On the other hand, short duration firings - pulses on the order of 0.1 seconds - can be thought of as impulses in the spacecraft's torque. These types of inputs will excite the structural modes of the spacecraft, causing the sail to oscillate. Sail oscillations are undesirable for many reasons. Mainly, these oscillations will feed into the spacecraft attitude sensors and pointing accuracy, and long term oscillations may be undesirable over the lifetime of the solar sail. In order to limit the sail oscillations, an RCS control scheme is being developed to minimize sail excitations. Specifically, an input shaping scheme similar to the method described in Reference 1 will be employed. A detailed description of the RCS control scheme will

  4. Strong Solar Control of Infrared Aurora on Jupiter: Correlation Since the Last Solar Maximum

    NASA Technical Reports Server (NTRS)

    Kostiuk, T.; Livengood, T. A.; Hewagama, T.

    2009-01-01

    Polar aurorae in Jupiter's atmosphere radiate throughout the electromagnetic spectrum from X ray through mid-infrared (mid-IR, 5 - 20 micron wavelength). Voyager IRIS data and ground-based spectroscopic measurements of Jupiter's northern mid-IR aurora, acquired since 1982, reveal a correlation between auroral brightness and solar activity that has not been observed in Jovian aurora at other wavelengths. Over nearly three solar cycles, Jupiter auroral ethane emission brightness and solar 10.7 cm radio flux and sunspot number are positively correlated with high confidence. Ethane line emission intensity varies over tenfold between low and high solar activity periods. Detailed measurements have been made using the GSFC HIPWAC spectrometer at the NASA IRTF since the last solar maximum, following the mid-IR emission through the declining phase toward solar minimum. An even more convincing correlation with solar activity is evident in these data. Current analyses of these results will be described, including planned measurements on polar ethane line emission scheduled through the rise of the next solar maximum beginning in 2009, with a steep gradient to a maximum in 2012. This work is relevant to the Juno mission and to the development of the Europa Jupiter System Mission. Results of observations at the Infrared Telescope Facility (IRTF) operated by the University of Hawaii under Cooperative Agreement no. NCC5-538 with the National Aeronautics and Space Administration, Science Mission Directorate, Planetary Astronomy Program. This work was supported by the NASA Planetary Astronomy Program.

  5. An approach for the control method's determination for an interplanetary mission with solar sail

    NASA Astrophysics Data System (ADS)

    Gorbunova, Irina; Starinova, Olga

    2017-01-01

    This article is devoted to an interplanetary movement of the solar sail spacecraft. Authors propose to use locally-optimal control laws for the solar sail control model. We used previously obtained by the authors locally-optimal control laws for chosen interplanetary missions. The obtained laws can provide rapid change of Keplerian elements or stabilize its values. Authors offer an approach for combination of these laws. To confirm the result correctness authors simulated the heliocentric motion of the solar sail spacecraft to the selected planet. Model of solar sail spacecraft called Helios is designed by students of Samara State Aerospace University. We define heliocentric motion of the solar sail spacecraft via Keplerian elements. Authors used combination technique for locally-optimal control laws to obtained several trajectories for interplanetary missions. The distinctive feature of the proposed method that parameters of osculating elements are used as destination phase coordinates.

  6. Modeling, Simulation, and Control of a Solar Electric Propulsion Vehicle in Near-Earth Vicinity Including Solar Array Degradation

    NASA Technical Reports Server (NTRS)

    Witzberger, Kevin (Inventor); Hojnicki, Jeffery (Inventor); Manzella, David (Inventor)

    2016-01-01

    Modeling and control software that integrates the complexities of solar array models, a space environment, and an electric propulsion system into a rigid body vehicle simulation and control model is provided. A rigid body vehicle simulation of a solar electric propulsion (SEP) vehicle may be created using at least one solar array model, at least one model of a space environment, and at least one model of a SEP propulsion system. Power availability and thrust profiles may be determined based on the rigid body vehicle simulation as the SEP vehicle transitions from a low Earth orbit (LEO) to a higher orbit or trajectory. The power availability and thrust profiles may be displayed such that a user can use the displayed power availability and thrust profiles to determine design parameters for an SEP vehicle mission.

  7. Evidence for solar wind control of Saturn radio emission

    NASA Technical Reports Server (NTRS)

    Desch, M. D.

    1982-01-01

    Using data collected by the Voyager 1 and 2 spacecraft in 1980 and 1981, strong evidence is presented for a direct correlation between variations in the solar wind at Saturn and the level of activity of Saturn's nonthermal radio emission. Correlation coefficients of 57 to 58% are reached at lag times of 0 to 1 days between the arrival at Saturn of high pressure solar wind streams and the onset of increased radio emission. The radio emission exhibits a long-term periodicity of 25 days, identical to the periodicity seen in the solar wind at this time and consistent with the solar rotation period. The energy coupling efficiency between the solar wind with the Saturn radio emission is estimated and compared with that for Earth.

  8. Solar wind control of auroral zone geomagnetic activity

    NASA Technical Reports Server (NTRS)

    Clauer, C. R.; Mcpherron, R. L.; Searls, C.; Kivelson, M. G.

    1981-01-01

    Solar wind magnetosphere energy coupling functions are analyzed using linear prediction filtering with 2.5 minute data. The relationship of auroral zone geomagnetic activity to solar wind power input functions are examined, and a least squares prediction filter, or impulse response function is designed from the data. Computed impulse response functions are observed to have characteristics of a low pass filter with time delay. The AL index is found well related to solar wind energy functions, although the AU index shows a poor relationship. High frequency variations of auroral indices and substorm expansions are not predictable with solar wind information alone, suggesting influence by internal magnetospheric processes. Finally, the epsilon parameter shows a poorer relationship with auroral geomagnetic activity than a power parameter, having a VBs solar wind dependency.

  9. SOLERAS - Solar Controlled Environment Agriculture Project. Final report, Volume 4. Saudi Engineering Solar Energy Applications System Design Study

    SciTech Connect

    Not Available

    1985-01-01

    Literature summarizing a study on the Saudi Arabian solar controlled environment agriculture system is presented. Specifications and performance requirements for the system components are revealed. Detailed performance and cost analyses are used to determine the optimum design. A preliminary design of an engineering field test is included. Some weather data are provided for Riyadh, Saudi Arabia. (BCS)

  10. 78 FR 61389 - Sanyo Solar of Oregon, LLC, Wafer Slicing and Quality Control Operations, Including On-Site...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-03

    ... Employment and Training Administration Sanyo Solar of Oregon, LLC, Wafer Slicing and Quality Control... to workers of Sanyo Solar of Oregon, LLC, Wafer Slicing and Quality Control Operations, Salem, Oregon... Salem, Oregon location of Sanyo Solar of Oregon, LLC, Wafer Slicing and Quality Control Operations....

  11. Deployment dynamics and control of large-scale flexible solar array system with deployable mast

    NASA Astrophysics Data System (ADS)

    Li, Hai-Quan; Liu, Xiao-Feng; Guo, Shao-Jing; Cai, Guo-Ping

    2016-10-01

    In this paper, deployment dynamics and control of large-scale flexible solar array system with deployable mast are investigated. The adopted solar array system is introduced firstly, including system configuration, deployable mast and solar arrays with several mechanisms. Then dynamic equation of the solar array system is established by the Jourdain velocity variation principle and a method for dynamics with topology changes is introduced. In addition, a PD controller with disturbance estimation is designed to eliminate the drift of spacecraft mainbody. Finally the validity of the dynamic model is verified through a comparison with ADAMS software and the deployment process and dynamic behavior of the system are studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the large-scale flexible solar arrays and the proposed controller is practical to eliminate the drift of spacecraft mainbody.

  12. Solar attitude control including active nutation damping in a fixed-momentum wheel satellite

    NASA Astrophysics Data System (ADS)

    Azor, Ruth

    1992-08-01

    In geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances, caused mainly by solar pressure. This work presents a roll/yaw control, which is obtained by the use of solar arrays and fixed flaps as actuators, with a horizon sensor for roll measurement. The design also includes an active nutation damping.

  13. Solar sail attitude control including active nutation damping in a fixed-momentum wheel satellite

    NASA Technical Reports Server (NTRS)

    Azor, Ruth

    1992-01-01

    In geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances, caused mainly by solar radiation pressure. This work presents a roll/yaw control which is obtained by the use of solar arrays and fixed flaps as actuators, with a horizon sensor for roll measurement. The design also includes an active nutation damping.

  14. Electrical charging control apparatus and method, and solar to electrical energy conversion apparatus incorporating such charging control apparatus

    SciTech Connect

    Staler, T.; Yerkes, J.W.

    1984-06-05

    Electrical charging control apparatus regulates the charging of a rechargeable battery by a solar panel. The control of the charging is through a relay which when closed directly connects the output and charging terminal of the solar panel to the output and charging terminal of the battery to permit the charging of the battery by the solar panel. Such coupling is in turn under the terminals are in a coupling prevention relationship chosen to prevent significant discharging of the battery through the solar panel; of breaker apparatus which breaks a coupling after a predetermined period of time; and of additional signal-tester apparatus which causes a termination of the coupling when the signal at the connected terminals reaches a chosen charging termination threshold. The breaking of the coupling, which can result in a periodic breaking, permits the testing for discharging prevention. A charging control method is in accordance with the above outlined method of operation of the charging control apparatus.

  15. Solar Particle Induced Upsets in the TDRS-1 Attitude Control System RAM During the October 1989 Solar Particle Events

    NASA Technical Reports Server (NTRS)

    Croley, D. R.; Garrett, H. B.; Murphy, G. B.; Garrard,T. L.

    1995-01-01

    The three large solar particle events, beginning on October 19, 1989 and lasting approximately six days, were characterized by high fluences of solar protons and heavy ions at 1 AU. During these events, an abnormally large number of upsets (243) were observed in the random access memory of the attitude control system (ACS) control processing electronics (CPE) on-board the geosynchronous TDRS-1 (Telemetry and Data Relay Satellite). The RAM unit affected was composed of eight Fairchild 93L422 memory chips. The Galileo spacecraft, launched on October 18, 1989 (one day prior to the solar particle events) observed the fluxes of heavy ions experienced by TDRS-1. Two solid-state detector telescopes on-board Galileo, designed to measure heavy ion species and energy, were turned on during time periods within each of the three separate events. The heavy ion data have been modeled and the time history of the events reconstructed to estimate heavy ion fluences. These fluences were converted to effective LET spectra after transport through the estimated shielding distribution around the TDRS-1 ACS system. The number of single event upsets (SEU) expected was calculated by integrating the measured cross section for the Fairchild 93L422 memory chip with average effective LET spectrum. The expected number of heavy ion induced SEU's calculated was 176. GOES-7 proton data, observed during the solar particle events, were used to estimate the number of proton-induced SEU's by integrating the proton fluence spectrum incident on the memory chips, with the two-parameter Bendel cross section for proton SEU'S. The proton fluence spectrum at the device level was gotten by transporting the protons through the estimated shielding distribution. The number of calculated proton-induced SEU's was 72, yielding a total of 248 predicted SEU'S, very dose to the 243 observed SEU'S. These calculations uniquely demonstrate the roles that solar heavy ions and protons played in the production of SEU

  16. Solar sail attitude control including active nutation damping in a fixed-momentum wheel satellite

    NASA Astrophysics Data System (ADS)

    Azor, Ruth

    1992-02-01

    In the geostationary cruise of a momentum biased satellite, it is necessary to stabilize the roll/yaw attitude due to disturbances caused by solar radiation pressure. This work presents a roll/yaw control system with a horizon sensor for roll measurement. Roll/yaw control is obtained by the use of solar arrays and fixed flaps as actuators. The design also includes an active nutation damping method.

  17. Thermal control evaluation of a Shuttle Orbiter solar observatory using Skylab ATM backup hardware

    NASA Technical Reports Server (NTRS)

    Class, C. R.; Presta, G.; Trucks, H.

    1975-01-01

    A study under the sponsorship of Marshall Space Flight Center (MSFC) established the feasibility to utilize the Skylab Apollo Telescope Mount (ATM) backup hardware for early low cost Shuttle Orbiter solar observation missions. A solar inertial attitude and a seven-day, full sun exposure were baselined. As a portion of the study, a series of thermal control evaluations were performed to resolve the problems caused by the relocation of the ATM to the Shuttle Orbiter bay and resulting configuration changes. Thermal control requirements, problems, the use of solar shields, Spacelab supplied fluid cooling and component placement are discussed.

  18. Solar wind dynamic pressure and electric field as the main factors controlling Saturn's aurorae.

    PubMed

    Crary, F J; Clarke, J T; Dougherty, M K; Hanlon, P G; Hansen, K C; Steinberg, J T; Barraclough, B L; Coates, A J; Gérard, J-C; Grodent, D; Kurth, W S; Mitchell, D G; Rymer, A M; Young, D T

    2005-02-17

    The interaction of the solar wind with Earth's magnetosphere gives rise to the bright polar aurorae and to geomagnetic storms, but the relation between the solar wind and the dynamics of the outer planets' magnetospheres is poorly understood. Jupiter's magnetospheric dynamics and aurorae are dominated by processes internal to the jovian system, whereas Saturn's magnetosphere has generally been considered to have both internal and solar-wind-driven processes. This hypothesis, however, is tentative because of limited simultaneous solar wind and magnetospheric measurements. Here we report solar wind measurements, immediately upstream of Saturn, over a one-month period. When combined with simultaneous ultraviolet imaging we find that, unlike Jupiter, Saturn's aurorae respond strongly to solar wind conditions. But in contrast to Earth, the main controlling factor appears to be solar wind dynamic pressure and electric field, with the orientation of the interplanetary magnetic field playing a much more limited role. Saturn's magnetosphere is, therefore, strongly driven by the solar wind, but the solar wind conditions that drive it differ from those that drive the Earth's magnetosphere.

  19. Biomass Burning Controlled Modulation of the Solar Radiation in Brazil

    NASA Astrophysics Data System (ADS)

    Pereira, E. B.; Martins, F. R.; Abreu, S. L.; Couto, P.; Colle, S.; Stuhlmann, R.

    1999-01-01

    Atmospheric combustion products from forest fires in Brazil can affect routine satellite techniques for the assessment of solar energy resource information. The mean overestimation of solar irradiance by BRASIL-SR clear sky model was up to 2.5 times larger than that found outside the region of biomass burnings. Within the region of biomass burnings the overestimation was over 5 times larger at the peak of the burning season when compared to the rest of the year. A positive correlation between combustion products and the number of fire spots counted by satellite technique suggests a possible method for the parameterization of these effects in radiation transfer models

  20. Solar wind control of magnetospheric pressure (CDAW 6)

    NASA Technical Reports Server (NTRS)

    Fairfield, D. H.

    1985-01-01

    The CDAW 6 data base is used to compare solar wind and magnetospheric pressures. The flaring angle of the tail magnetopause is determined by assuming that the component of solar wind pressure normal to the tail boundary is equal to the total pressure within the tail. Results indicate an increase in the tail flaring angle from 18 deg to 32 deg prior to the 1055 substorm onset and a decrease to 25 deg after the onset. This behavior supports the concept of tail energy storage before the substorm and subsequent release after the onset.

  1. Control of an orbiting flexible square platform in the presence of solar radiation

    NASA Technical Reports Server (NTRS)

    Bainum, P. M.; Krishna, R.

    1985-01-01

    An analysis is made of the dynamics of a thin, homogeneous, flexible square plate exposed to solar radiation disturbance. It is shown that only the first three flexible modes of the plate generate a first order net moment about the center of mass and that the solar radiation pressure does not influence the flexible modes of the plate for small-amplitude vibrations. In the absence of control, for a symmetrical homogeneous square platform, the solar radiation induces a steady angular drift about one of the body principal axes. For extremely flexible platforms, nominally oriented in the local horizontal plane, appreciable rigid modal amplitudes can be induced due to solar radiation, even in the presence of both active and passive control. Optimal control law and feedback gain values are obtained using linear quadratic Gaussian methods.

  2. A dynamic solar-electric power/thermal control system for spacecraft.

    NASA Technical Reports Server (NTRS)

    Davis, B. K.

    1972-01-01

    This paper describes a solar-electric power and active thermal control system for spacecraft with solar energy to electricity conversion efficiency of more than 20%. Briefly, the solar heat energy is absorbed by flat plate collectors yielding above 70% of the energy incident for conversion by an organic condensing cycle. The cycle operates between 132 and 6.67 deg C. The working fluid is F-114 which flows through a solar collector to absorb heat, then through a regenerator and into the radiator where it is condensed to a liquid. The cold liquid flows through two paths, one providing regenerator cooling, the other providing spacecraft thermal control. The system total weight is about 170kg/kW of electrical energy produced. The dynamic system replaces batteries by a thermal capacitor for eclipse period energy storage, thereby eliminating many battery charging and control problems as well as improving efficiency and weight characteristics of the system.

  3. Control-structure interaction study for the Space Station solar dynamic power module

    NASA Technical Reports Server (NTRS)

    Cheng, J.; Ianculescu, G.; Ly, J.; Kim, M.

    1991-01-01

    The authors investigate the feasibility of using a conventional PID (proportional plus integral plus derivative) controller design to perform the pointing and tracking functions for the Space Station Freedom solar dynamic power module. Using this simple controller design, the control/structure interaction effects were also studied without assuming frequency bandwidth separation. From the results, the feasibility of a simple solar dynamic control solution with a reduced-order model, which satisfies the basic system pointing and stability requirements, is suggested. However, the conventional control design approach is shown to be very much influenced by the order of reduction of the plant model, i.e., the number of the retained elastic modes from the full-order model. This suggests that, for complex large space structures, such as the Space Station Freedom solar dynamic, the conventional control system design methods may not be adequate.

  4. Magnetosheath control of solar wind-magnetosphere coupling efficiency

    NASA Astrophysics Data System (ADS)

    Pulkkinen, T. I.; Dimmock, A. P.; Lakka, A.; Osmane, A.; Kilpua, E.; Myllys, M.; Tanskanen, E. I.; Viljanen, A.

    2016-09-01

    We examine the role of the magnetosheath in solar wind-magnetosphere-ionosphere coupling using the Time History of Events and Macroscale Interactions during Substorms plasma and magnetic field observations in the magnetosheath together with OMNI solar wind data and auroral electrojet recordings from the International Monitor for Auroral Geomagnetic Effects (IMAGE) magnetometer chain. We demonstrate that the electric field and Poynting flux reaching the magnetopause are not linear functions of the electric field and Poynting flux observed in the solar wind: the electric field and Poynting flux at the magnetopause during higher driving conditions are lower than those predicted from a linear function. We also show that the Poynting flux normal to the magnetopause is linearly correlated with the directly driven part of the auroral electrojets in the ionosphere. This indicates that the energy entering the magnetosphere in the form of the Poynting flux is directly responsible for driving the electrojets. Furthermore, we argue that the polar cap potential saturation discussed in the literature is associated with the way solar wind plasma gets processed during the bow shock crossing and motion within the magnetosheath.

  5. The social control of energy: A case for the promise of decentralized solar technologies

    NASA Astrophysics Data System (ADS)

    Gilmer, R. W.

    1980-05-01

    Decentralized solar technology and centralized electric utilities were contrasted in the ways they assign property rights in capital and energy output; in the assignment of operational control; and in the means of monitoring, policing, and enforcing property rights. An analogy was drawn between the decision of an energy consumer to use decentralized solar and the decision of a firm to vertically integrate, that is, to extend the boundary of a the firm to vertically integrate, that is, to extend the boundary of the firm by making inputs or further processing output. Decentralized solar energy production offers the small energy consumer the chance to cut ties to outside suppliers--to vertically integrate energy production into the home or business. The development of this analogy provides insight into important noneconomic aspects of solar energy, and it points clearly to the lighter burdens of social management offered by decentralized solar technology.

  6. Attitude control study for a large flexible spacecraft using a Solar Electric Propulsion System (SEPS)

    NASA Technical Reports Server (NTRS)

    Tolivar, A. F.; Key, R. W.

    1980-01-01

    The attitude control performance of the solar electric propulsion system (SEPS) was evaluated. A thrust vector control system for powered flight control was examined along with a gas jet reaction control system, and a reaction wheel system, both of which have been proposed for nonpowered flight control. Comprehensive computer simulations of each control system were made and evaluated using a 30 mode spacecraft model. Results obtained indicate that thrust vector control and reaction wheel systems offer acceptable smooth proportional control. The gas jet control system is shown to be risky for a flexible structure such as SEPS, and is therefore, not recommended as a primary control method.

  7. Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor

    NASA Astrophysics Data System (ADS)

    Afiqah Zainal, Nurul; Sooi Tat, Chan; Ajisman

    2016-02-01

    Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.

  8. Evaluation of Steam and Soil Solarization for Meloidogyne arenaria Control in Florida Floriculture Crops

    PubMed Central

    Kokalis-Burelle, Nancy; Rosskopf, Erin N.; Butler, David M.; Fennimore, Steven A.; Holzinger, John

    2016-01-01

    Steam and soil solarization were investigated for control of the root-knot nematode Meloidogyne arenaria in 2 yr of field trials on a commercial flower farm in Florida. The objective was to determine if preplant steam treatments in combination with solarization, or solarization alone effectively controlled nematodes compared to methyl bromide (MeBr). Trials were conducted in a field with naturally occurring populations of M. arenaria. Treatments were solarization alone, steam treatment after solarization using standard 7.6-cm-diameter perforated plastic drain tile (steam 1), steam treatment following solarization using custom-drilled plastic drain tile with 1.6-mm holes spaced every 3.8 cm (steam 2), and MeBr applied at 392 kg/ha 80:20 MeBr:chloropicrin. Drain tiles were buried approximately 35 cm deep with four tiles per 1.8 by 30 m plot. Steam application followed a 4-wk solarization period concluding in mid-October. All steam was generated using a Sioux propane boiler system. Plots were steamed for sufficient time to reach the target temperature of 70°C for 20 min. Solarization plastic was retained on the plots during steaming and plots were covered with a single layer of carpet padding to provide additional insulation. The floriculture crops larkspur (Delphinium elatum and Delphinium × belladonna), snapdragon (Antirrhinum majus), and sunflower (Helianthus annuus) were produced according to standard commercial practices. One month after treatment in both years of the study, soil populations of M. arenaria were lower in both steam treatments and in MeBr compared to solarization alone. At the end of the season in both years, galling on larkspur, snapdragon, and sunflowers was lower in both steam treatments than in solarization. Both steam treatments also provided control of M. arenaria in soil at the end of the season comparable to, or exceeding that provided by MeBr. Both steam treatments also reduced M. arenaria in snapdragon roots comparable to, or exceeding

  9. Evaluation of Steam and Soil Solarization for Meloidogyne arenaria Control in Florida Floriculture Crops.

    PubMed

    Kokalis-Burelle, Nancy; Rosskopf, Erin N; Butler, David M; Fennimore, Steven A; Holzinger, John

    2016-09-01

    Steam and soil solarization were investigated for control of the root-knot nematode Meloidogyne arenaria in 2 yr of field trials on a commercial flower farm in Florida. The objective was to determine if preplant steam treatments in combination with solarization, or solarization alone effectively controlled nematodes compared to methyl bromide (MeBr). Trials were conducted in a field with naturally occurring populations of M. arenaria. Treatments were solarization alone, steam treatment after solarization using standard 7.6-cm-diameter perforated plastic drain tile (steam 1), steam treatment following solarization using custom-drilled plastic drain tile with 1.6-mm holes spaced every 3.8 cm (steam 2), and MeBr applied at 392 kg/ha 80:20 MeBr:chloropicrin. Drain tiles were buried approximately 35 cm deep with four tiles per 1.8 by 30 m plot. Steam application followed a 4-wk solarization period concluding in mid-October. All steam was generated using a Sioux propane boiler system. Plots were steamed for sufficient time to reach the target temperature of 70°C for 20 min. Solarization plastic was retained on the plots during steaming and plots were covered with a single layer of carpet padding to provide additional insulation. The floriculture crops larkspur (Delphinium elatum and Delphinium × belladonna), snapdragon (Antirrhinum majus), and sunflower (Helianthus annuus) were produced according to standard commercial practices. One month after treatment in both years of the study, soil populations of M. arenaria were lower in both steam treatments and in MeBr compared to solarization alone. At the end of the season in both years, galling on larkspur, snapdragon, and sunflowers was lower in both steam treatments than in solarization. Both steam treatments also provided control of M. arenaria in soil at the end of the season comparable to, or exceeding that provided by MeBr. Both steam treatments also reduced M. arenaria in snapdragon roots comparable to, or exceeding

  10. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    DOE PAGES

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; ...

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructedmore » solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.« less

  11. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    SciTech Connect

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; Gracia, Jose R.; King, Thomas Jr.; Liu, Yilu

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructed solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.

  12. Fuzzy logic controller versus classical logic controller for residential hybrid solar-wind-storage energy system

    NASA Astrophysics Data System (ADS)

    Derrouazin, A.; Aillerie, M.; Mekkakia-Maaza, N.; Charles, J. P.

    2016-07-01

    Several researches for management of diverse hybrid energy systems and many techniques have been proposed for robustness, savings and environmental purpose. In this work we aim to make a comparative study between two supervision and control techniques: fuzzy and classic logics to manage the hybrid energy system applied for typical housing fed by solar and wind power, with rack of batteries for storage. The system is assisted by the electric grid during energy drop moments. A hydrogen production device is integrated into the system to retrieve surplus energy production from renewable sources for the household purposes, intending the maximum exploitation of these sources over years. The models have been achieved and generated signals for electronic switches command of proposed both techniques are presented and discussed in this paper.

  13. Application of Semi Active Control Techniques to the Damping Suppression Problem of Solar Sail Booms

    NASA Technical Reports Server (NTRS)

    Adetona, O.; Keel, L. H.; Whorton, M. S.

    2007-01-01

    Solar sails provide a propellant free form for space propulsion. These are large flat surfaces that generate thrust when they are impacted by light. When attached to a space vehicle, the thrust generated can propel the space vehicle to great distances at significant speeds. For optimal performance the sail must be kept from excessive vibration. Active control techniques can provide the best performance. However, they require an external power-source that may create significant parasitic mass to the solar sail. However, solar sails require low mass for optimal performance. Secondly, active control techniques typically require a good system model to ensure stability and performance. However, the accuracy of solar sail models validated on earth for a space environment is questionable. An alternative approach is passive vibration techniques. These do not require an external power supply, and do not destabilize the system. A third alternative is referred to as semi-active control. This approach tries to get the best of both active and passive control, while avoiding their pitfalls. In semi-active control, an active control law is designed for the system, and passive control techniques are used to implement it. As a result, no external power supply is needed so the system is not destabilize-able. Though it typically underperforms active control techniques, it has been shown to out-perform passive control approaches and can be unobtrusively installed on a solar sail boom. Motivated by this, the objective of this research is to study the suitability of a Piezoelectric (PZT) patch actuator/sensor based semi-active control system for the vibration suppression problem of solar sail booms. Accordingly, we develop a suitable mathematical and computer model for such studies and demonstrate the capabilities of the proposed approach with computer simulations.

  14. Solar wind control of Jupiter's decametric radio emission

    NASA Technical Reports Server (NTRS)

    Barrow, C. H.; Genova, F.; Desch, M. D.

    1986-01-01

    Observations of the solar wind close to Jupiter are compared with the decametric radio emission (DAM), using data recorded by Voyager 1 and Voyager 2 during 1979. The Non-Io DAM, recorded by both spacecraft and combined using the superposed epoch technique, is found to correlate with the solar wind density and velocity, as well as with the interplanetary magnetic field (IMF) magnitude. In agreement with earlier work using ground-based observations, there are indications that the Non-Io DAM is somehow associated with magnetic sector structure although the precise details of the relationship are still not known and it is not clear if this is a fundamental effect or some secondary effect of intercorrelation.

  15. Photoinduced Charge Transport in a BHJ Solar Cell Controlled by an External Electric Field

    PubMed Central

    Li, Yongqing; Feng, Yanting; Sun, Mengtao

    2015-01-01

    This study investigated theoretical photoinduced charge transport in a bulk heterojunction (BHJ) solar cell controlled by an external electric field. Our method for visualizing charge difference density identified the excited state properties of photoinduced charge transfer, and the charge transfer excited states were distinguished from local excited states during electronic transitions. Furthermore, the calculated rates for the charge transfer revealed that the charge transfer was strongly influenced by the external electric field. The external electric field accelerated the rate of charge transfer by up to one order when charge recombination was significantly restrained. Our research demonstrated that photoinduced charge transport controlled by an external electric field in a BHJ solar cell is efficient, and the exciton dissociation is not the limiting factor in organic solar cells.Our research should aid in the rational design of a novel conjugated system of organic solar cells. PMID:26353997

  16. Evaluation of thermal control coatings for use on solar dynamic radiators in low earth orbit

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

    1991-01-01

    Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

  17. Evaluation of thermal control coatings for use on solar dynamic radiators in low Earth orbit

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

    1991-01-01

    Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

  18. Solar wind control of the distant magnetotail: ISEE 3

    NASA Technical Reports Server (NTRS)

    Fairfield, D. H.

    1993-01-01

    During a 40-day period in 1983, International Sun Earth Explorer 3 (ISEE 3) was located about 225 R(sub E) behind the Earth and remained within 12 R(sub E) of the nominal tail axis. During this time the spacecraft spent at least 70% of its time in the magnetotail with occasional excursions into the magnetosheath. However, during five geomagnetically distrubed intervals of 1 - 3 days duration during this period, ISEE 3 remained within the magnetosheath for extended intervals, even when it was very near the center of an average tail. Simultaneous observations of the solar wind direction and thermal pressure suggest that nonradial solar wind flow associated with interacting solar wind streams moves a compressed tail away from the nominal position at these times and explains most of these observations. However, during several few-hour intervals of strongly northward interplanetary magnetic field (IMF) within these periods, the solar wind is more radial and cannot explain the residence of the spacecraft in the magnetosheath. At these times ISEE 3 seems to be moving back and forth between two regions, one a higher-density, lower-temperature magnetosheathlike region but with density somewhat lower than the normal magnetosheath, the other a lower-density, higher-temperature taillike region but with density higher than the normal tail. Both regions have larger B(sub z) components and B(sub x) components that tend to vary as if the spacecraft were moving from one hemisphere of the tail to the other. It is suggested that the magnetotail at these times of northward IMF consists mostly of field lines that close Earthward of the spacecraft with a narrow remaining tail at 225 R(sub E) waving back and forth across the spacecraft. If relatively rare intervals of long-duration, very northward IMF can eliminate the extended tail, it seems likely that more common, less northward IMF might well have very important, though less drastic, effects on the tail configurations.

  19. Solar Wind Control of the Magnetospheric and Auroral Dynamics

    NASA Astrophysics Data System (ADS)

    Alexeev, I. I.

    2006-02-01

    A dependence of the polar cap magnetic flux on the interplanetary magnetic field and on the solar wind dynamic pressure is studied. The model calculations of the polar cap and auroral oval magnetic fluxes at the ionospheric level are presented. The obtained functions are based on the paraboloid magnetospheric model calculations. The scaling law for the polar cap diameter changing for different subsolar distances is demonstrated. Quiet conditions are used to compare theoretical results with the UV images of the Earth’s polar region obtained onboard the Polar and IMAGE spacecrafts. The model calculations enable finding not only the average polar cap magnetic flux but also the extreme values of the polar cap and auroral oval magnetic fluxes. These values can be attained in the course of the severe magnetic storm. Spectacular aurora often can be seen at midlatitude during severe magnetic storm. In particularly, the Bastille Day storm of July 15 16, 2000, was a severe magnetic storm when auroral displays were reported at midlatitudes. Enhancement of global magnetospheric current systems (ring current and tail current) and corresponding reconstruction of the magnetospheric structure is a reason for the equatorward displacement of the auroral zone. But at the start of the studied event the contracted polar cap and auroral oval were observed. In this case, the sudden solar wind pressure pulse was associated with a simultaneous northward IMF turning. Such IMF and solar wind pressure behavior is a cause of the observed aurora dynamics.

  20. Canopy Level Solar Induced Fluorescence for Vegetation in Controlled Experiments

    NASA Technical Reports Server (NTRS)

    Middleton, E. M.; Corp, L. A.; Campbell, P. K. Entcheva

    2007-01-01

    Solar induced chlorophyll fluorescence (SIF) was retrieved from high resolution reflectance spectra acquired one meter above saplings of three deciduous tree species during springtime (three weeks after leaf flush) and in late summer when foliage was mature. SIF was determined by application of the Fraunhofer Line Depth (FLD) Principal to above-canopy spectra acquired with an Analytical Spectral Devices (ASD) Fieldspec spectroradiometer (3.2 nm resolution with 1.2 nm sampling interval). SIF retrievals were made at the two atmospheric oxygen (O2) absorption features that occur in the chlorophyll fluorescence (ChlF) region (660 -780 nm). These telluric features are 02V, the broader and deeper feature centered at 760 nm, but located on the shoulder of the far-red ChlF peak at 740 nm; and 023, a narrow feature centered at 688 nm that is positioned near the red ChlF peak at 685 nm. Supporting, coincident leaf level fluorescence, reflectance, photochemical and other measurements were also made. At the leaf level, these measurements included in situ photosynthetic capacity (Pmax) and light adapted total chlorophyll fluorescence (Fs') collected at steady state under high light and controlled chamber conditions (e.g., temperature, PAR, humidity, and COz); optical properties (reflectance, transmittance, absorptance); chlorophyll and carotenoid content; specific leaf mass; carbon (C) and nitrogen (N) content; fluorescence emission spectra at multiple excitation wavelengths; the ChlF contribution to red (R) and far-red (FR) reflectance; fluorescence imagery; and fluorescence excitation-emission matrices (EEMs). The tree species examined were tulip poplar (Liriodendron tulipifera L.), red maple (Acer rubrum L.), and sweetgum (Liquidambar styraczflua L.), and each had been provided four levels of N augmentation (0, 19, 37, and 75 kg Nhectare seasonally) to simulate atmospheric deposition from air pollution. Whole-plant SIF measurements of these species were compared with SIF

  1. Orbit Control of Fly-around Satellite with Highly Eccentric Orbit Using Solar Radiation Pressure

    NASA Astrophysics Data System (ADS)

    Yong-gang, Hou; Chang-yin, Zhao; Ming-jiang, Zhang; Rong-yu, Sun

    2017-01-01

    The method of controlling highly eccentric accompanying flight orbit using the solar wing is proposed in this paper. The formation is maintained by controlling the orbit of the accompanying satellite (follower). The accompanying satellite rotates around its inertial principal axis with a constant angular velocity. The control on the accompanying satellite is divided into the in-plane control and out-of-plane control. The in-plane control is superior to the out-of-plane control. The out-of-plane control force is applied when the in-plane error is eliminated or the in-plane control force can not be supplied due to some geometrical factors. By the sliding mode control method, the magnitude and direction of the control force required by the in-plane orbit control are calculated. Then accordingly, the expression of the solar wing orientation with respect to the satellite body in the control process is derived, so that by adjusting the orientation of the solar wing, the required control force can be obtained. Finally, the verification on this method is performed by numerical simulations, including the orbit adjustment, error elimination, and the orbit maintenance. It is shown that this method can keep the error less than 5 m, and it is feasible for the space formation flight.

  2. Combined Contamination and Space Environmental Effects on Solar Cells and Thermal Control Surfaces

    NASA Technical Reports Server (NTRS)

    Dever, Joyce A.; Bruckner, Eric J.; Scheiman, David A.; Stidham, Curtis R.

    1994-01-01

    For spacecraft in low Earth orbit (LEO), contamination can occur from thruster fuel, sputter contamination products and from products of silicone degradation. This paper describes laboratory testing in which solar cell materials and thermal control surfaces were exposed to simulated spacecraft environmental effects including contamination, atomic oxygen, ultraviolet radiation and thermal cycling. The objective of these experiments was to determine how the interaction of the natural LEO environmental effects with contaminated spacecraft surfaces impacts the performance of these materials. Optical properties of samples were measured and solar cell performance data was obtained. In general, exposure to contamination by thruster fuel resulted in degradation of solar absorptance for fused silica and various thermal control surfaces and degradation of solar cell performance. Fused silica samples which were subsequently exposed to an atomic oxygen/vacuum ultraviolet radiation environment showed reversal of this degradation. These results imply that solar cells and thermal control surfaces which are susceptible to thruster fuel contamination and which also receive atomic oxygen exposure may not undergo significant performance degradation. Materials which were exposed to only vacuum ultraviolet radiation subsequent to contamination showed slight additional degradation in solar absorptance.

  3. Combined contamination and space environmental effects on solar cells and thermal control surfaces

    SciTech Connect

    Dever, J.A.; Bruckner, E.J.; Scheiman, D.A.; Stidham, C.R.

    1994-05-01

    For spacecraft in low Earth orbit (LEO), contamination can occur from thruster fuel, sputter contamination products and from products of silicone degradation. This paper describes laboratory testing in which solar cell materials and thermal control surfaces were exposed to simulated spacecraft environmental effects including contamination, atomic oxygen, ultraviolet radiation and thermal cycling. The objective of these experiments was to determine how the interaction of the natural LEO environmental effects with contaminated spacecraft surfaces impacts the performance of these materials. Optical properties of samples were measured and solar cell performance data was obtained. In general, exposure to contamination by thruster fuel resulted in degradation of solar absorptance for fused silica and various thermal control surfaces and degradation of solar cell performance. Fused silica samples which were subsequently exposed to an atomic oxygen/vacuum ultraviolet radiation environment showed reversal of this degradation. These results imply that solar cells and thermal control surfaces which are susceptible to thruster fuel contamination and which also receive atomic oxygen exposure may not undergo significant performance degradation. Materials which were exposed to only vacuum ultraviolet radiation subsequent to contamination showed slight additional degradation in solar absorptance.

  4. Application of model reference adaptive control to solar thermal utilization systems

    SciTech Connect

    Tanaka, T. )

    1990-05-01

    A proportional plus integral plus derivative (PID) controller is used to obtain usable energy from the sun in almost all the solar systems in Japan. However, it is difficult to collect the heat continuously close to a prescribed temperature using a PID controller because the solar radiation is often interrupted by passing clouds. The authors investigated, therefore, a model reference adaptive control (MRAC) system. In order to demonstrate its effectiveness, we constructed a MRAC system and introduced it into the collector loop of a solar system. This paper gives an outline of the MRAC algorithm and describes the experimental results for the outlet fluid temperature response of the loop by the MRAC and PID. From these results, it is shown that the MRAC algorithm is suitable for controlling a system affected by irregular disturbances in the insolation.

  5. A theoretical study of the modelling and control of a solar water electrolysis plant

    NASA Astrophysics Data System (ADS)

    Vandergeest, P.; Fahidy, T. Z.

    1980-01-01

    A control-oriented model is presented for a hydrogen producing plant consisting of a conventional water electrolysis process and a photo-assisted water electrolytic installation which utilizes solar energy via a suitable semiconductor/electrolyte assembly. A control strategy for daily hydrogen production is illustrated by a numerical example. The proposed simulation of solar water electrolysis plants is of potential usefulness for automatic control of the photoelectrolytic process when combined with statistical data-logging and model updating carried out in a practical installation.

  6. Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The final results of the design and operation of a computer controlled solar heated and cooled 40,000 square foot manufacturing building, sales office, and computer control center/display room are summarized. The system description, test data, major problems and resolutions, performance, operation and maintenance manual, equipment manufacturers' literature, and as-built drawings are presented. The solar system is composed of 6,000 square feet of flat plate collectors, external above ground storage subsystem, controls, absorption chiller, heat recovery, and a cooling tower.

  7. Solar Heating and Cooling for a Controls Manufacturing Plant Lumberton, New Jersey

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Comprehensive report documents computer-controlled system which has separate solar-collector and cooling-tower areas located away from building and is completely computer controlled. System description, test data, major problems and resolution, performance, operation and maintenance, manufacturer's literature and drawing comprise part of 257-page report.

  8. Shape Control of Solar Collectors Using Shape Memory Alloy Actuators

    NASA Technical Reports Server (NTRS)

    Lobitz, D. W.; Grossman, J. W.; Allen, J. J.; Rice, T. M.; Liang, C.; Davidson, F. M.

    1996-01-01

    Solar collectors that are focused on a central receiver are designed with a mechanism for defocusing the collector or disabling it by turning it out of the path of the sun's rays. This is required to avoid damaging the receiver during periods of inoperability. In either of these two cases a fail-safe operation is very desirable where during power outages the collector passively goes to its defocused or deactivated state. This paper is principally concerned with focusing and defocusing the collector in a fail-safe manner using shape memory alloy actuators. Shape memory alloys are well suited to this application in that once calibrated the actuators can be operated in an on/off mode using a minimal amount of electric power. Also, in contrast to other smart materials that were investigated for this application, shape memory alloys are capable of providing enough stroke at the appropriate force levels to focus the collector. Design and analysis details presented, along with comparisons to test data taken from an actual prototype, demonstrate that the collector can be repeatedly focused and defocused within accuracies required by typical solar energy systems. In this paper the design, analysis and testing of a solar collector which is deformed into its desired shape by shape memory alloy actuators is presented. Computations indicate collector shapes much closer to spherical and with smaller focal lengths can be achieved by moving the actuators inward to a radius of approximately 6 inches. This would require actuators with considerably more stroke and some alternate SMA actuators are currently under consideration. Whatever SMA actuator is finally chosen for this application, repeatability and fatigue tests will be required to investigate the long term performance of the actuator.

  9. Polymer Solar Cells: Solubility Controls Fiber Network Formation.

    PubMed

    van Franeker, Jacobus J; Heintges, Gaël H L; Schaefer, Charley; Portale, Giuseppe; Li, Weiwei; Wienk, Martijn M; van der Schoot, Paul; Janssen, René A J

    2015-09-16

    The photoactive layer of polymer solar cells is commonly processed from a four-component solution, containing a semiconducting polymer and a fullerene derivative dissolved in a solvent-cosolvent mixture. The nanoscale dimensions of the polymer-fullerene morphology that is formed upon drying determines the solar cell performance, but the fundamental processes that govern the size of the phase-separated polymer and fullerene domains are poorly understood. Here, we investigate morphology formation of an alternating copolymer of diketopyrrolopyrrole and a thiophene-phenyl-thiophene oligomer (PDPPTPT) with relatively long 2-decyltetradecyl (DT) side chains blended with [6,6]-phenyl-C71-butyric acid methyl ester. During solvent evaporation the polymer crystallizes into a fibrous network. The typical width of these fibers is analyzed by quantification of transmission electron microscopic images, and is mainly determined by the solubility of the polymer in the cosolvent and the molecular weight of the polymer. A higher molecular weight corresponds to a lower solubility and film processing results in a smaller fiber width. Surprisingly, the fiber width is not related to the drying rate or the amount of cosolvent. We have made solar cells with fiber widths ranging from 28 to 68 nm and found an inverse relation between fiber width and photocurrent. Finally, by mixing two cosolvents, we develop a ternary solvent system to tune the fiber width. We propose a model based on nucleation-and-growth which can explain these measurements. Our results show that the width of the semicrystalline polymer fibers is not the result of a frozen dynamical state, but determined by the nucleation induced by the polymer solubility.

  10. Gradient zone boundary control in salt gradient solar ponds

    DOEpatents

    Hull, John R.

    1984-01-01

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  11. A practical approach to Model Predictive Control (MPC) for solar communities

    NASA Astrophysics Data System (ADS)

    Quintana, Humberto

    Solar district heating (SDH) systems are part of the solution to reduce energy consumption and GHG emissions required for space heating. This kind of installation takes advantage of the convenience of a centralized system and of solar energy to reduce dependency on fossil-fuels. An SDH system is a proven concept that can be enhanced with the addition of long-term thermal energy storage to compensate the seasonal disparity between solar energy supply and heating load demand. These systems are especially deployed in Europe. In Canada, the only SDH installation is the Drake Landing Solar Community (DLSC). This project, which includes seasonal storage (Borehole Thermal Energy Storage-BTES), has been a remarkable success, reaching a solar fraction of 97% by the fifth year of operation. An SDH system cannot be complete without an appropriate supervisory control that coordinates the operation and interaction of system components. The control is based on a set of rules that must consider the system's internal status and external conditions to guarantee occupant comfort with minimal fossil-fuels consumption. This research project is mainly focused on conceiving and assessing new control mechanisms aiming towards an increase of SDH systems' overall energy efficiency. The case study is the DLSC plant, and the proposed control strategies are based on the practical application of Model Predictive Control (MPC) theory. A calibrated model of DLSC including the supervisory control strategies was developed in TRNSYS, building upon the model used for design studies. The model was improved and new components were created when needed. The calibration process delivered a very good agreement for the most important yearly energy performance indices (2 % for solar heat input to the district and for gas consumption, and 5 % for electricity use). Proposed control strategies were conceived for modifying four aspects of the current control: the parameters that define the interaction between

  12. Active thermal control for the 1.8-m primary mirror of the solar telescope CLST

    NASA Astrophysics Data System (ADS)

    Liu, Yangyi; Gu, Naiting; Li, Cheng; Cheng, Yuntao; Yao, Benxi; Wang, Zhiyong; Rao, Changhui

    2016-07-01

    The 1.8-m primary mirror of solar telescope is heated by the solar radiation and introduce harmful mirror seeing degrading the imaging quality. For the Chinese Large Solar Telescope (CLST), the thermal requirement based on the quantitative evaluation on mirror seeing effect shows that the temperature rise on mirror surface should be within 1 kelvin. To meet the requirement, an active thermal control system design for the CLST primary mirror is proposed, and realized on the subscale prototype of the CLST. The experimental results show that the temperature on the mirror surface is well controlled. The average and maximum thermal controlled error are less than 0.3 and 0.7 kelvins respectively, which completely meets the requirements.

  13. Evaluation of operational control strategies applicable to solar chimney power plants

    SciTech Connect

    Bernardes, Marco Aurelio dos Santos; von Backstroem, Theodor W.

    2010-02-15

    Numerical simulations are carried out to study the performance of two schemes of power output control applicable to solar chimney power plants. Either the volume flow or the turbine pressure drop is used as independent control variable. Values found in the literature for the optimum ratio of turbine pressure drop to pressure potential vary between 2/3 and 0.97. It is shown that the optimum ratio is not constant during the whole day and it is dependent of the heat transfer coefficients applied to the collector. This study is a contribution towards understanding solar chimney power plant performance and control and may be useful in the design of solar chimney turbines. (author)

  14. Morphology-Controlled High-Efficiency Small Molecule Organic Solar Cells without Additive Solvent Treatment

    PubMed Central

    Kim, Il Ku; Jo, Jun Hyung; Yun, Jung-Ho

    2016-01-01

    This paper focuses on nano-morphology-controlled small-molecule organic solar cells without solvent treatment for high power-conversion efficiencies (PCEs). The maximum high PCE reaches up to 7.22% with a bulk-heterojunction (BHJ) thickness of 320 nm. This high efficiency was obtained by eliminating solvent additives such as 1,8-diiodooctane (DIO) to find an alternative way to control the domain sizes in the BHJ layer. Furthermore, the generalized transfer matrix method (GTMM) analysis has been applied to confirm the effects of applying a different thickness of BHJs for organic solar cells from 100 to 320 nm, respectively. Finally, the study showed an alternative way to achieve high PCE organic solar cells without additive solvent treatments to control the morphology of the bulk-heterojunction.

  15. Adaptive control of the packet transmission period with solar energy harvesting prediction in wireless sensor networks.

    PubMed

    Kwon, Kideok; Yang, Jihoon; Yoo, Younghwan

    2015-04-24

    A number of research works has studied packet scheduling policies in energy scavenging wireless sensor networks, based on the predicted amount of harvested energy. Most of them aim to achieve energy neutrality, which means that an embedded system can operate perpetually while meeting application requirements. Unlike other renewable energy sources, solar energy has the feature of distinct periodicity in the amount of harvested energy over a day. Using this feature, this paper proposes a packet transmission control policy that can enhance the network performance while keeping sensor nodes alive. Furthermore, this paper suggests a novel solar energy prediction method that exploits the relation between cloudiness and solar radiation. The experimental results and analyses show that the proposed packet transmission policy outperforms others in terms of the deadline miss rate and data throughput. Furthermore, the proposed solar energy prediction method can predict more accurately than others by 6.92%.

  16. Analytical control laws of the heliocentric motion of the solar sail spacecraft

    NASA Astrophysics Data System (ADS)

    Gorbunova, Irina; Starinova, Olga

    2014-12-01

    The heliocentric motion of the solar sail spacecraft is described in classical Keplerian elements. The flat of solar sail with an ideal reflection coefficient is considered. The spacecraft performs a noncoplanar motion with the sun gravity and the light pressure. Disturbances of other celestial bodies gravity are not considered. We have received analytical terms for laws to control a solar sail, which ensure constancy or maximum rate of change of the Keplerian elements. To confirm the results correctness, we simulated the solar sail spacecraft. The spacecraft's initial orbit coincides with the average Earth orbit relative to the Sun. Authors developed a program complex to simulated the planar heliocentric movement and obtained results for motion simulation of flights to Mars and Venus. The results were compared with the simulation results obtained using the Pontryagin maximum principle.

  17. SOLERAS - Solar Controlled Environment Agriculture Project. Final report, Volume 1. Project summary

    SciTech Connect

    Not Available

    1985-12-30

    A summary of the Solar Controlled Environment Agriculture Project is presented. The design of the greenhouses include transparent double pane glass roof with channels for fluid between the panes, inner pane tinted and double pane extruded acrylic aluminized mylar shade and diffuser. Solar energy technologies provide power for water desalination, for pumping irrigation water, and for cooling and heating the controlled environment space so that crops can grow in arid lands. The project is a joint effort between the United States and Saudi Arabia. (BCS)

  18. Real time intelligent process control system for thin film solar cell manufacturing

    SciTech Connect

    George Atanasoff

    2010-10-29

    This project addresses the problem of lower solar conversion efficiency and waste in the typical solar cell manufacturing process. The work from the proposed development will lead toward developing a system which should be able to increase solar panel conversion efficiency by an additional 12-15% resulting in lower cost panels, increased solar technology adoption, reduced carbon emissions and reduced dependency on foreign oil. All solar cell manufacturing processes today suffer from manufacturing inefficiencies that currently lead to lower product quality and lower conversion efficiency, increased product cost and greater material and energy consumption. This results in slower solar energy adoption and extends the time solar cells will reach grid parity with traditional energy sources. The thin film solar panel manufacturers struggle on a daily basis with the problem of thin film thickness non-uniformity and other parameters variances over the deposited substrates, which significantly degrade their manufacturing yield and quality. Optical monitoring of the thin films during the process of the film deposition is widely perceived as a necessary step towards resolving the non-uniformity and non-homogeneity problem. In order to enable the development of an optical control system for solar cell manufacturing, a new type of low cost optical sensor is needed, able to acquire local information about the panel under deposition and measure its local characteristics, including the light scattering in very close proximity to the surface of the film. This information cannot be obtained by monitoring from outside the deposition chamber (as traditional monitoring systems do) due to the significant signal attenuation and loss of its scattering component before the reflected beam reaches the detector. In addition, it would be too costly to install traditional external in-situ monitoring systems to perform any real-time monitoring over large solar panels, since it would require

  19. Nutation and precession control of the High Energy Solar Physics (HESP) satellite

    NASA Technical Reports Server (NTRS)

    Jayaraman, C. P.; Robertson, B. P.

    1993-01-01

    The High Energy Solar Physics (HESP) spacecraft is an intermediate class satellite proposed by NASA to study solar high-energy phenomena during the next cycle of high solar activity in the 1998 to 2005 time frame. The HESP spacecraft is a spinning satellite which points to the sun with stringent pointing requirements. The natural dynamics of a spinning satellite includes an undesirable effect: nutation, which is due to the presence of disturbances and offsets of the spin axis from the angular momentum vector. The proposed Attitude Control System (ACS) attenuates nutation with reaction wheels. Precessing the spacecraft to track the sun in the north-south and east-west directions is accomplished with the use of torques from magnetic torquer bars. In this paper, the basic dynamics of a spinning spacecraft are derived, control algorithms to meet HESP science requirements are discussed and simulation results to demonstrate feasibility of the ACS concept are presented.

  20. A disturbance isolation controller for the solar electric propulsion system flight experiment

    NASA Technical Reports Server (NTRS)

    Waites, H. B.

    1982-01-01

    A disturbance isolation controller (DIC) is developed for a simplified model of the solar electric propulsion system (SEPS) flight experiment which consists of a rigid Sperry gimbal torquer (AGS) mounted to a rigid orbiter and the SEPS solar array (rigid) end mounted to the AGS. The main purpose of the DIC is to reduce the effects of orbiter disturbances which are transmitted to the flight experiment. The DIC uses an observer, which does not require the direct measurement of the plant inputs, to obtain estimates of the plant states and the rate of the plant states. The state and rate of state information is used to design a controller which isolates disturbances from specified segments of the plant, and for the flight experiment, the isolated segment is the SEPS solar array.

  1. Robust optimal sun-pointing control of a large solar power satellite

    NASA Astrophysics Data System (ADS)

    Wu, Shunan; Zhang, Kaiming; Peng, Haijun; Wu, Zhigang; Radice, Gianmarco

    2016-10-01

    The robust optimal sun-pointing control strategy for a large geostationary solar power satellite (SPS) is addressed in this paper. The SPS is considered as a huge rigid body, and the sun-pointing dynamics are firstly proposed in the state space representation. The perturbation effects caused by gravity gradient, solar radiation pressure and microwave reaction are investigated. To perform sun-pointing maneuvers, a periodically time-varying robust optimal LQR controller is designed to assess the pointing accuracy and the control inputs. It should be noted that, to reduce the pointing errors, the disturbance rejection technique is combined into the proposed LQR controller. A recursive algorithm is then proposed to solve the optimal LQR control gain. Simulation results are finally provided to illustrate the performance of the proposed closed-loop system.

  2. Maximum Output Power Control Using Short-Circuit Current and Open-Circuit Voltage of a Solar Panel

    NASA Astrophysics Data System (ADS)

    Kato, Takahiro; Miyake, Takuma; Tashima, Daisuke; Sakoda, Tatsuya; Otsubo, Masahisa; Hombu, Mitsuyuki

    2012-10-01

    A control method to optimize the output power of a solar cell is necessary because the output of a solar cell strongly depends on solar radiation. We here proposed two output power control methods using the short-circuit current and open-circuit voltage of a solar panel. One of them used a current ratio and a voltage ratio (αβ control), and the other used a current ratio and a short-circuit current-electric power characteristic coefficient (αγ control). The usefulness of the αβ and the αγ control methods was evaluated. The results showed that the output power controlled by our proposed methods was close to the maximum output power of a solar panel.

  3. Mechanical and Electrical Behavior of Organic Solar Cells Probed Through Detailed Morphological Control

    NASA Astrophysics Data System (ADS)

    Awartani, Omar Marwan

    One of the main advantages of organic solar cells is their potential to be used in flexible or even stretchable applications. Most research in the field of organic solar cells is focused on materials synthesis, device physics, and the relationship between morphology and the optoelectronic performance. In order for this technology to be commercially competitive, especially for flexible applications, a more complete picture that explores the mechanical properties of organic materials and how they relate to their optoelectronic properties is necessary. This thesis consists of two main research tracks: The first track focuses mainly on the effect of morphology on the mechanical, electrical and optical performance of organic solar cells controlled through varying processing conditions. Two mechanical properties are investigated including the elastic modulus and crack onset strain of P3HT, PCBM and blend (BHJ) films. The second track utilizes the high achievable ductility of organic semiconducting films that is investigated in the first track of the thesis, to create novel solar cell device architectures and to gain insight into the performance and recombination losses of organic solar cells. Processing ductile BHJ films is used to create organic solar cells with controlled level of polarization with both opaque and semi-transparent architectures. Moreover, using the strain-alignment method the efficiency of low and high order P3HT aggregates is probed within the same film to show similar internal quantum efficiency for the two different morphological P3HT domains. This selective probing technique provides significant insight into performance loss mechanisms in organic solar cells.

  4. On designing of the driven system control of solar panels using type 2 fuzzy sliding mode control (T2FSMC)

    NASA Astrophysics Data System (ADS)

    Mardlijah, Subiono, S., Sentot D.; Efprianto, Yahya

    2016-02-01

    Collectors on the solar panel can work optimally when the collectors position perpendicular to the whole solar rays. Therefore we need a control system to control the position of the collectors always perpendicular to the sun rays. In this paper, control system T2FSMC is proposed, combined SMC, FLC and fuzzy type 2 which has a membership function more complex so as to provide an additional degree of freedom that allows uncertainty. the behavior of the control system based on T2FSMC for the driven system of solar panels was analyzed by comparing T2FSMC with FSMC and SMC methods. It can be concluded that the system controller of T2FSMC works better than the system controller of FSMC and SMC; i.e. faster response time, more robust to large and small disturbance and more robust to parameter uncertainty. However, the lacks in the system T2FSMC are taking quite a long time in computation and need fuzzy logic reasoning.

  5. Precise Morphology Control and Continuous Fabrication of Perovskite Solar Cells Using Droplet-Controllable Electrospray Coating System.

    PubMed

    Hong, Seung Chan; Lee, Gunhee; Ha, Kyungyeon; Yoon, Jungjin; Ahn, Namyoung; Cho, Woohyung; Park, Mincheol; Choi, Mansoo

    2017-03-08

    Herein, we developed a novel electrospray coating system for continuous fabrication of perovskite solar cells with high performance. Our system can systemically control the size of CH3NH3PbI3 precursor droplets by modulating the applied electrical potential, shown to be a crucial factor for the formation of perovskite films. As a result, we have obtained pinhole-free and large grain-sized perovskite solar cells, yielding the best PCE of 13.27% with little photocurrent hysteresis. Furthermore, the average PCE through the continuous coating process was 11.56 ± 0.52%. Our system demonstrates not only the high reproducibility but also a new way to commercialize high-quality perovskite solar cells.

  6. Development status on the real-time controller for solar multi-conjugate adaptive optics system

    NASA Astrophysics Data System (ADS)

    Kong, Lin; Zhu, Lei; Rao, Changhui

    2016-10-01

    Solar observations are performed over an extended field of view (FoV) and the isoplanatic patch which conventional adaptive optics (AO) provides diffraction limited resolution is a severe limitation. Multi-conjugate Adaptive Optics (MCAO) can be used to extend the corrected FoV of AO system. Compared to AO, MCAO which usually utilizes a wide-field Shack-Hartmann wavefront sensor to control multiple deformable mirrors(DMs) is more complicated. Because the Sun is an extended object, correlation algorithms are applied to detect gradients in solar MCAO system. Moreover, due to the fast evolving daytime seeing conditions and the fact that much science has to be done at visible wavelengths, a very high closed-loop bandwidth is also required. The computation and delay development of the real-time controller (RTC) in solar MCAO system is more challenging than that in night-time MCAO system. This paper reviews the solar MCAO techniques and systems in the world, especially emphasizes the framework and implementation of the RTC. The development of MCAO in China is also introduced. An outlook of the RTC for the solar MCAO system in development is given.

  7. The solar wind control of Jupiter's broad-band kilometric radio emission

    NASA Technical Reports Server (NTRS)

    Barrow, C. H.; Leblanc, Y.; Desch, M. D.

    1988-01-01

    Observations of the solar wind close to Jupiter are compared with the broad-band kilometric radio emission (bKOM), using data recorded by Voyager 1 and Voyager 2 during 1979. The lower bKOM frequencies, less than about 300 kHz, are found to correlate with the solar wind density and pressure and with the interplanetary magnetic field (IMF) magnitude during periods when there is a well-defined magnetic sector structure. The results suggest that lower frequency bKOM events are most likely to occur after a sector boundary has passed Jupiter during the period when the solar wind density and the IMF magnitude are increasing towards the sector center. The average bKOM energy per Jovian rotation tends to have lower values soon after the sector center has passed. Higher-frequency/higher-energy bKOM emission may be contaminated by hectometric emission (HOM) and differently correlated with solar activity. The solar wind control may also be obscured by some stronger control. It is suggested that electron density fluctuations in the Io torus, where the source is believed to be located, may be responsible for variations in the beaming and hence variations in the observed emission.

  8. Modular control subsystems for use in solar heating systems for multi-family dwellings

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Progress in the development of solar heating modular control subsystems is reported. Circuit design, circuit drawings, and printed circuit board layout are discussed along with maintenance manuals, installation instructions, and verification and acceptance tests. Calculations made to determine the predicted performance of the differential thermostat are given including details and results of tests for the offset temperature, and boil and freeze protect points.

  9. Recent Advances in Heliogyro Solar Sail Structural Dynamics, Stability, and Control Research

    NASA Technical Reports Server (NTRS)

    Wilkie, W. Keats; Warren, Jerry E.; Horta, Lucas G.; Lyle, Karen H.; Juang, Jer-Nan; Gibbs, S. Chad; Dowell, Earl H.; Guerrant, Daniel V.; Lawrence, Dale

    2015-01-01

    Results from recent NASA sponsored research on the structural dynamics, stability, and control characteristics of heliogyro solar sails are summarized. Specific areas under investigation include coupled nonlinear finite element analysis of heliogyro membrane blade with solar radiation pressure effects, system identification of spinning membrane structures, and solarelastic stability analysis of heliogyro solar sails, including stability during blade deployment. Recent results from terrestrial 1-g blade dynamics and control experiments on "rope ladder" membrane blade analogs, and small-scale in vacuo system identification experiments with hanging and spinning high-aspect ratio membranes will also be presented. A low-cost, rideshare payload heliogyro technology demonstration mission concept is used as a mission context for these heliogyro structural dynamics and solarelasticity investigations, and is also described. Blade torsional dynamic response and control are also shown to be significantly improved through the use of edge stiffening structural features or inclusion of modest tip masses to increase centrifugal stiffening of the blade structure. An output-only system identification procedure suitable for on-orbit blade dynamics investigations is also developed and validated using ground tests of spinning sub-scale heliogyro blade models. Overall, analytical and experimental investigations to date indicate no intractable stability or control issues for the heliogyro solar sail concept.

  10. Solar Systems and Energy Management Controls. Final Report, 1982-83.

    ERIC Educational Resources Information Center

    Bergen County Vocational-Technical High School, Hackensack, NJ.

    This project was conducted by the Bergen County Vocational-Technical Schools (1) to develop a practical awareness of energy conservation and management techniques for both commercial and domestic applications; (2) to develop four training courses to teach solar troubleshooting and maintenance, commercial energy management control, domestic energy…

  11. Effects of number and position of meta and para carboxyphenyl groups of zinc porphyrins in dye-sensitized solar cells: structure-performance relationship.

    PubMed

    Ambre, Ram B; Mane, Sandeep B; Chang, Gao-Fong; Hung, Chen-Hsiung

    2015-01-28

    Porphyrin sensitizers containing meta- and para-carboxyphenyl groups in their meso positions have been synthesized and investigated for their performance in dye-sensitized solar cells (DSSCs). The superior performance of para-derivative compared to meta-derivative porphyrins was revealed by optical spectroscopy, electrochemical property measurements, density functional theory (DFT) calculations, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, incident photon-to-current conversion efficiency (IPCE), electrochemical impedance spectroscopy (EIS), and stability performance. Absorption spectra of para-carboxyphenyl-substituted porphyrins on TiO2 show a broader Soret band compared to meta-carboxyphenyl-substituted porphyrins. ATR-FTIR spectra of the studied porphyrins on TiO2 were applied to investigate the number and mode of carboxyl groups attached to TiO2. The VOC, JSC, and IPCE values of para-series porphyrins were distinctly superior to those of meta-series porphyrins. The Nyquist plots of the studied porphyrins show that charge injection in para-series porphyrins is superior to that in meta-series porphyrins. The orthogonally positioned para derivatives have more efficient charge injection and charge transfer over charge recombination, whereas the efficiencies of flat-oriented meta derivatives are retarded by rapid charge recombination. Photovoltaic measurements of the studied meta- and para-carboxyphenyl-functionalized porphyrins show that the number and position of carboxyphenyl groups play a crucial role in the performance of the DSSC. Our results indicate that para-carboxyphenyl derivatives outperform meta-carboxyphenyl derivatives to give better device performance. This study will serve as a guideline for the design and development of organic, porphyrin, and ruthenium dyes in DSSCs.

  12. Tuning the properties of polymer bulk heterojunction solar cells by adjusting fullerene size to control intercalation.

    PubMed

    Cates, Nichole C; Gysel, Roman; Beiley, Zach; Miller, Chad E; Toney, Michael F; Heeney, Martin; McCulloch, Iain; McGehee, Michael D

    2009-12-01

    We demonstrate that intercalation of fullerene derivatives between the side chains of conjugated polymers can be controlled by adjusting the fullerene size and compare the properties of intercalated and nonintercalated poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT):fullerene blends. The intercalated blends, which exhibit optimal solar-cell performance at 1:4 polymer:fullerene by weight, have better photoluminescence quenching and lower absorption than the nonintercalated blends, which optimize at 1:1. Understanding how intercalation affects performance will enable more effective design of polymer:fullerene solar cells.

  13. System design and installation for RS600 programmable control system for solar heating and cooling

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Procedures for installing, operating, and maintaining a programmable control system which utilizes a F8 microprocessor to perform all timing, control, and calculation functions in order to customize system performance to meet individual requirements for solar heating, combined heating and cooling, and/or hot water systems are described. The manual discusses user configuration and options, displays, theory of operation, trouble-shooting procedures, and warranty and assistance. Wiring lists, parts lists, drawings, and diagrams are included.

  14. Alignment control study for the solar optical telescope

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Analysis of the alignment and focus errors than can be tolerated, methods of sensing such errors, and mechanisms to make the necessary corrections were addressed. Alternate approaches and their relative merits were considered. The results of this study indicate that adequate alignment control can be achieved.

  15. Automatic phase control in solar power satellite systems

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.; Kantak, A. V.

    1978-01-01

    Various approaches to the problem of generating, maintaining and distributing a coherent, reference phase signal over a large area are suggested, mathematically modeled and analyzed with respect to their ability to minimize: phase build-up, beam diffusion and beam steering phase jitter, cable length, and maximize power transfer efficiency. In addition, phase control configurations are suggested which alleviate the need for layout symmetry.

  16. An Open Source Low-Cost Wireless Control System for a Forced Circulation Solar Plant.

    PubMed

    Salamone, Francesco; Belussi, Lorenzo; Danza, Ludovico; Ghellere, Matteo; Meroni, Italo

    2015-11-05

    The article describes the design phase, development and practical application of a low-cost control system for a forced circulation solar plant in an outdoor test cell located near Milan. Such a system provides for the use of an electric pump for the circulation of heat transfer fluid connecting the solar thermal panel to the storage tank. The running plant temperatures are the fundamental parameter to evaluate the system performance such as proper operation, and the control and management system has to consider these parameters. A solar energy-powered wireless-based smart object was developed, able to monitor the running temperatures of a solar thermal system and aimed at moving beyond standard monitoring approaches to achieve a low-cost and customizable device, even in terms of installation in different environmental conditions. To this end, two types of communications were used: the first is a low-cost communication based on the ZigBee protocol used for control purposes, so that it can be customized according to specific needs, while the second is based on a Bluetooth protocol used for data display.

  17. An Open Source Low-Cost Wireless Control System for a Forced Circulation Solar Plant

    PubMed Central

    Salamone, Francesco; Belussi, Lorenzo; Danza, Ludovico; Ghellere, Matteo; Meroni, Italo

    2015-01-01

    The article describes the design phase, development and practical application of a low-cost control system for a forced circulation solar plant in an outdoor test cell located near Milan. Such a system provides for the use of an electric pump for the circulation of heat transfer fluid connecting the solar thermal panel to the storage tank. The running plant temperatures are the fundamental parameter to evaluate the system performance such as proper operation, and the control and management system has to consider these parameters. A solar energy-powered wireless-based smart object was developed, able to monitor the running temperatures of a solar thermal system and aimed at moving beyond standard monitoring approaches to achieve a low-cost and customizable device, even in terms of installation in different environmental conditions. To this end, two types of communications were used: the first is a low-cost communication based on the ZigBee protocol used for control purposes, so that it can be customized according to specific needs, while the second is based on a Bluetooth protocol used for data display. PMID:26556356

  18. Results of solar electric thrust vector control system design, development and tests

    NASA Technical Reports Server (NTRS)

    Fleischer, G. E.

    1973-01-01

    Efforts to develop and test a thrust vector control system TVCS for a solar-energy-powered ion engine array are described. The results of solar electric propulsion system technology (SEPST) III real-time tests of present versions of TVCS hardware in combination with computer-simulated attitude dynamics of a solar electric multi-mission spacecraft (SEMMS) Phase A-type spacecraft configuration are summarized. Work on an improved solar electric TVCS, based on the use of a state estimator, is described. SEPST III tests of TVCS hardware have generally proved successful and dynamic response of the system is close to predictions. It appears that, if TVCS electronic hardware can be effectively replaced by control computer software, a significant advantage in control capability and flexibility can be gained in future developmental testing, with practical implications for flight systems as well. Finally, it is concluded from computer simulations that TVCS stabilization using rate estimation promises a substantial performance improvement over the present design.

  19. Data Acquisition, Control, Communication and Computation System of Solar X-ray Spectrometer (SOXS) Mission

    NASA Astrophysics Data System (ADS)

    Shah, Amish B.; Vadher, N. M.; Jain, Rajma; Dave, Hemant; Shah, Vishal; Manian, K. S. B.; Kayasth, Satish; Patel, Vinod; Ubale, Girish; Shah, Kirit; Solanki, Chirag; Deshpande, M. R.; Sharma, Ramkrishna; Umapathy, C. N.; Viswanath, N.; Kulkarni, Ravi; Kumar, P. S.

    2006-09-01

    The Solar X-ray Spectrometer (SOXS) mission onboardGSAT- 2 Indian Spacecraft was launched on 08 May 2003 using GSLV-D2 rocket by Indian Space Research Organization (ISRO). SOXS aims to study solar flares, which are the most violent and energetic phenomena in the solar system, in the energy range of 4-56 keV with high spectral and temporal resolution. SOXS employs state-of-the-art semiconductor devices, viz., Si-Pin and CZT detectors to achieve sub-keV energy resolution requirements. In this paper, we present an overview of data acquisition, control,communication and computation of low energy payload of the SOXS mission.

  20. Improved morphology control using a modified two-step method for efficient perovskite solar cells.

    PubMed

    Bi, Dongqin; El-Zohry, Ahmed M; Hagfeldt, Anders; Boschloo, Gerrit

    2014-11-12

    A two-step wet chemical synthesis method for methylammonium lead(II) triiodide (CH3NH3PbI3) perovskite is further developed for the preparation of highly reproducible solar cells, with the following structure: fluorine-doped tin oxide (FTO)/TiO2 (compact)/TiO2 (mesoporous)/CH3NH3PbI3/spiro-OMeTAD/Ag. The morphology of the perovskite layer could be controlled by careful variation of the processing conditions. Specifically, by modifying the drying process and inclusion of a dichloromethane treatment, more uniform films could be prepared, with longer emission lifetime in the perovskite material and longer electron lifetime in solar cell devices, as well as faster electron transport and enhanced charge collection at the selective contacts. Solar cell efficiencies up to 13.5% were obtained.

  1. Analysis of selective reflection spectrum in cholesteric liquid crystal cells for solar-ray controller

    NASA Astrophysics Data System (ADS)

    Ogiwara, Akifumi; Kakiuchida, Hiroshi

    2015-09-01

    The cholesteric liquid crystal (CLC) cells are fabricated by varying the concentration of various chiral dopants and liquid crystal (LC) diacrylate monomers. The wavelength and bandwidth of selective reflection spectrum in CLC cells are measured by a spectroscopic technique. The variation of the selective reflection spectrum in CLC cells is investigated by doping the different kinds of liquid crystal (LC) diacrylate monomers which stabilize a helical twisting structure by photopolymerization. The effects of the selective reflection spectrum on the visible and infrared lights in spectral solar irradiance are explained by the performance for a solar-ray controller based on the spectral solar irradiance for air mass 1.5 and the standard luminous efficiency function for photopic vision.

  2. A comparative study between control strategies for a solar sailcraft in an Earth-Mars transfer

    NASA Astrophysics Data System (ADS)

    Mainenti-Lopes, I.; Souza, L. C. Gadelha; De Sousa, Fabiano. L.

    2016-10-01

    The goal of this work was a comparative study of solar sail trajectory optimization using different control strategies. Solar sailcraft is propulsion system with great interest in space engineering, since it uses solar radiation to propulsion. So there is no need for propellant to be used, thus it can remains active throughout the entire transfer maneuver. This type of propulsion system opens the possibility to reduce the cost of exploration missions in the solar system. In its simplest configuration, a Flat Solar Sail (FSS) consists of a large and thin structure generally composed by a film fixed to flexible rods. The performance of these vehicles depends largely on the sails attitude relative to the Sun. Using a FSS as propulsion, an Earth-Mars transfer optimization problem was tackled by the algorithms GEOreal1 and GEOreal2 (Generalized Extremal Optimization with real codification). Those algorithms are Evolutionary Algorithms (AE) based on the theory of Self-Organized Criticality. They were used to optimize the FSS attitude angle so it could reach Mars orbit in minimum time. It was considered that the FSS could perform up to ten attitude maneuvers during orbital transfer. Moreover, the time between maneuvers can be different. So, the algorithms had to optimize an objective function with 20 design variables. The results obtained in this work were compared with previously results that considered constant values of time between maneuvers.

  3. Structural dynamic interaction with solar tracking control for evolutionary Space Station concepts

    NASA Technical Reports Server (NTRS)

    Lim, Tae W.; Cooper, Paul A.; Ayers, J. Kirk

    1992-01-01

    The sun tracking control system design of the Solar Alpha Rotary Joint (SARJ) and the interaction of the control system with the flexible structure of Space Station Freedom (SSF) evolutionary concepts are addressed. The significant components of the space station pertaining to the SARJ control are described and the tracking control system design is presented. Finite element models representing two evolutionary concepts, enhanced operations capability (EOC) and extended operations capability (XOC), are employed to evaluate the influence of low frequency flexible structure on the control system design and performance. The design variables of the control system are synthesized using a constrained optimization technique to meet design requirements, to provide a given level of control system stability margin, and to achieve the most responsive tracking performance. The resulting SARJ control system design and performance of the EOC and XOC configurations are presented and compared to those of the SSF configuration. Performance limitations caused by the low frequency of the dominant flexible mode are discussed.

  4. Design of a solar controlled environment agriculture system (SCEAS)

    SciTech Connect

    Landstrom, D.K.; Stickford, G.H.; Talbert, S.G.; Wilkinson, W.H.

    1983-06-01

    The overall objective of the SCEAS project was to integrate advanced greenhouse agriculture technology with various energy sources and innovative cooling/ventilation concepts to demonstrate technical and economic feasibility of these facilities in several climatic regions where conventional greenhouse technology will not permit yearround growing of certain crops. The designed facility is capable of high yields of practically any crop, even temperaturesensitive vegetables such as lettuce, in extremely hostile external environments. The recirculation and ventilation system provides considerable flexibility in precise control of temperature and humidity throughout the year and in reducing water and energy consumption.

  5. Integrated Orbit, Attitude, and Structural Control Systems Design for Space Solar Power Satellites

    NASA Technical Reports Server (NTRS)

    Wie, Bong; Roithmayr, Carlos M.

    2001-01-01

    The major objective of this study is to develop an integrated orbit, attitude, and structural control systems architecture for very large Space Solar Power Satellites (SSPS) in geosynchronous orbit. This study focuses on the 1.2-GW Abacus SSPS concept characterized by a 3.2 x 3.2 km solar-array platform, a 500-m diameter microwave beam transmitting antenna, and a 500 x 700 m earth-tracking reflector. For this baseline Abacus SSPS configuration, we derive and analyze a complete set of mathematical models, including external disturbances such as solar radiation pressure, microwave radiation, gravity-gradient torque, and other orbit perturbation effects. The proposed control systems architecture utilizes a minimum of 500 1-N electric thrusters to counter, simultaneously, the cyclic pitch gravity-gradient torque, the secular roll torque caused by an offset of the center-of-mass and center-of-pressure, the cyclic roll/yaw microwave radiation torque, and the solar radiation pressure force whose average value is about 60 N.

  6. Integrated Orbit, Attitude, and Structural Control System Design for Space Solar Power Satellites

    NASA Technical Reports Server (NTRS)

    Woods-Vedeler, Jessica (Technical Monitor); Moore, Chris (Technical Monitor); Wie, Bong; Roithmayr, Carlos

    2001-01-01

    The major objective of this study is to develop an integrated orbit, attitude, and structural control system architecture for very large Space Solar Power Satellites (SSPS) in geosynchronous orbit. This study focuses on the 1.2-GW Abacus SSPS concept characterized by a 3.2 x 3.2 km solar-array platform, a 500-m diameter microwave beam transmitting antenna, and a 500 700 m earth-tracking reflector. For this baseline Abacus SSPS configuration, we derive and analyze a complete set of mathematical models, including external disturbances such as solar radiation pressure, microwave radiation, gravity-gradient torque, and other orbit perturbation effects. The proposed control system architecture utilizes a minimum of 500 1-N electric thrusters to counter, simultaneously, the cyclic pitch gravity-gradient torque, the secular roll torque caused by an o.set of the center-of-mass and center-of-pressure, the cyclic roll/yaw microwave radiation torque, and the solar radiation pressure force whose average value is about 60 N.

  7. Power Flow Controller for Renewables: Transformer-less Unified Power Flow Controller for Wind and Solar Power Transmission

    SciTech Connect

    2012-02-08

    GENI Project: MSU is developing a power flow controller to improve the routing of electricity from renewable sources through existing power lines. The fast, innovative, and lightweight circuitry that MSU is incorporating into its controller will eliminate the need for a separate heavy and expensive transformer, as well as the construction of new transmission lines. MSU’s controller is better suited to control power flows from distributed and intermittent wind and solar power systems than traditional transformer-based controllers are, so it will help to integrate more renewable energy into the grid. MSU‘s power flow controller can be installed anywhere in the existing grid to optimize energy transmission and help reduce transmission congestion.

  8. Control of Photoluminescence of Carbon Nanodots via Surface Functionalization using Para-substituted Anilines

    PubMed Central

    Kwon, Woosung; Do, Sungan; Kim, Ji-Hee; Seok Jeong, Mun; Rhee, Shi-Woo

    2015-01-01

    Carbon nanodots (C-dots) are a kind of fluorescent carbon nanomaterials, composed of polyaromatic carbon domains surrounded by amorphous carbon frames, and have attracted a great deal of attention because of their interesting properties. There are still, however, challenges ahead such as blue-biased photoluminescence, spectral broadness, undefined energy gaps and etc. In this report, we chemically modify the surface of C-dots with a series of para-substituted anilines to control their photoluminescence. Our surface functionalization endows our C-dots with new energy levels, exhibiting long-wavelength (up to 650 nm) photoluminescence of very narrow spectral widths. The roles of para-substituted anilines and their substituents in developing such energy levels are thoroughly studied by using transient absorption spectroscopy. We finally demonstrate light-emitting devices exploiting our C-dots as a phosphor, converting UV light to a variety of colors with internal quantum yields of ca. 20%. PMID:26218869

  9. Controllable design of solid-state perovskite solar cells by SCAPS device simulation

    NASA Astrophysics Data System (ADS)

    Tan, Kai; Lin, Peng; Wang, Gang; Liu, Yan; Xu, Zongchang; Lin, Yixin

    2016-12-01

    The highest power conversion efficiency (PCE) of solid-state perovskite solar cells (ssPSCs) has achieved 20.1% recently. There is reason to believe that ssPSCs is a strong competitor with silicon and CIGS solar cells in photovoltaic field. The deep understanding of operation mechanism of ssPSCs is essential and required to furtherly improve device performance. The configuration and excition type are similar to inorganic semiconductor solar cells. Therefore, Solar Cell Capacitance Simulator (SCAPS), a device simulator widely using in inorganic solar cells, was employed to controllably design ssPSCs. The validity of device simulation was verified by comparing with real devices from reported literatures. The influence of absorber thickness on device property was discussed, which indicate that it exists an optimal thickness range. Two hypothetical interface layers, TiO2/perovskite layer and perovskite/HTM layer, were introduced into the construction model to consider the effects of interfaces defect density on device performance. It revealed TiO2/perovskite has stronger impact than perovskite/HTM, because higher excess carrier density existing at TiO2/perovskite will cause more recombination rate. In addition, hole transport materials (HTM) parameters, hole mobility and acceptor density, were chosen to study the impact of HTM characteristics on PCE. The analysis illuminate that the design of HTM layer should balance hole mobility and acceptor density. Meanwhile, different HTM candidates were selected and replaced typical HTM layer. The discussion about the function of candidates on solar cells performance demonstrated that a thiophene group hole-transporting polymer (PTAA) and a copper-based conductor (CuI) both have relatively high PCE, which is due to their wide bandgap, high conductivity, and better chemical interaction with perovskite absorber.

  10. Closed Loop solar array-ion thruster system with power control circuitry

    NASA Technical Reports Server (NTRS)

    Gruber, R. P. (Inventor)

    1979-01-01

    A power control circuit connected between a solar array and an ion thruster receives voltage and current signals from the solar array. The control circuit multiplies the voltage and current signals together to produce a power signal which is differentiated with respect to time. The differentiator output is detected by a zero crossing detector and, after suitable shaping, the detector output is phase compared with a clock in a phase demodulator. An integrator receives no output from the phase demodulator when the operating point is at the maximum power but is driven toward the maximum power point for non-optimum operation. A ramp generator provides minor variations in the beam current reference signal produced by the integrator in order to obtain the first derivative of power.

  11. Inverse problem for shape control of flexible space reflectors using distributed solar pressure

    NASA Astrophysics Data System (ADS)

    Borggräfe, A.; Heiligers, J.; Ceriotti, M.; McInnes, C. R.

    2014-07-01

    This paper investigates controlled elastic deflection of thin circular space reflectors using an inverse problem approach to non-linear thin membrane theory. When changing the surface reflectivity across the membrane, the distributed loads due to ambient solar radiation pressure can be manipulated optically, thus controlling the surface shape without using mechanical or piezo-electric systems. The surface reflectivity can in principle be modulated using uniformly distributed thin-film electro-chromic coatings. We present an analytic solution to the inverse problem of finding the necessary reflectivity distribution that creates a specific membrane deflection, for example that of a parabolic reflector. Importantly, the reflectivity distribution across the surface is found to be independent of membrane size, thickness and solar distance, enabling engineering of the reflectivity distribution directly during the manufacture of the membrane.

  12. Application of high refractive index and/or chromogenic layers to control solar and thermal radiations

    NASA Astrophysics Data System (ADS)

    Suzuki, Motofumi; Nishiura, Kensuke; Masunaka, Shoma; Muroi, Naoto; Namura, Kyoko

    2016-09-01

    In this presentation, we demonstrate that high refractive index materials such as β-FeSi2 and/or chromogenic materials such as VO2 are the key to control solar and thermal radiations. β-FeSi2 is known as an eco-friendly semiconductor and for sputtered polycrystalline β-FeSi2 thin films, we recently found that λ 0.3 in IR region, while n is higher than 5. On the other hand, another interesting optical property of β-FeSi2 is that both n and k are considerably high in visible to NIR region ( λ <= 1.55 μm). Using these optical properties in IR and VIS, we designed multilayers consisting of β-FeSi2/SiO2/β-FeSi2/W, where the upper β-FeSi2 layer absorbs VIS and NIR (λ <= 1.0 μm) and the bottom β-FeSi2 layer/W absorbs IR (1.0 <= λ <=2.0 μm). The optimized multilayers absorb more than 90% of solar energy and the eminence at 450 °C is lower than 10%. The perfect absorbers with high refractive index layers are useful for applications to solar selective absorbers for solar thermal power generation and spectrally selective thermal emitters for thermophotovoltaic power generation, IR heaters, radiation cooling. Replacing one of β-FeSi2 layers with a chromogenic material allows active control of solar and thermal radiation. In the presentation, we also demonstrate the active perfect absorbers including a VO2 layer in NIR region.

  13. Properties of conductive coatings for thermal control mirrors and solar cell covers

    NASA Technical Reports Server (NTRS)

    Joslin, D. E.; Kan, H. K. A.

    1975-01-01

    Conductive transparent coatings applied to the dielectric surfaces of a spacecraft offer the possibility of distributing charge uniformly over the entire spacecraft surface. Optical and electrical measurements of such a coating as a function of temperature are described. These results are used in considering the impact of a conductive coating on the absorptance of thermal control mirrors and on the transmittance of solar cell cover glass, which can be improved by the application of an antireflection coating.

  14. Microprocessor control of multiple peak power tracking DC/DC converters for use with solar cell arrays

    NASA Technical Reports Server (NTRS)

    Frederick, Martin E. (Inventor); Jermakian, Joel (Inventor)

    1991-01-01

    A method and an apparatus is provided for efficiently controlling the power output of a solar cell array string or a plurality of solar cell array strings to achieve a maximum amount of output power from the strings under varying conditions of use. Maximum power output from a solar array string is achieved through control of a pulse width modulated DC/DC buck converter which transfers power from a solar array to a load or battery bus. The input voltage from the solar array to the converter is controlled by a pulse width modulation duty cycle, which in turn is controlled by a differential signal controller. By periodically adjusting the control voltage up or down by a small amount and comparing the power on the load or bus with that generated at different voltage values a maximum power output voltage may be obtained. The system is totally modular and additional solar array strings may be added to the system simply by adding converter boards to the system and changing some constants in the controller's control routines.

  15. Control oriented concentrating solar power (CSP) plant model and its applications

    NASA Astrophysics Data System (ADS)

    Luo, Qi

    Solar receivers in concentrating solar thermal power plants (CSP) undergo over 10,000 start-ups and shutdowns, and over 25,000 rapid rate of change in temperature on receivers due to cloud transients resulting in performance degradation and material fatigue in their expected lifetime of over 30 years. The research proposes to develop a three-level controller that uses multi-input-multi-output (MIMO) control technology to minimize the effect of these disturbances, improve plant performance, and extend plant life. The controller can be readily installed on any vendor supplied state-of-the-art control hardware. We propose a three-level controller architecture using multi-input-multi-output (MIMO) control for CSP plants that can be implemented on existing plants to improve performance, reliability, and extend the life of the plant. This architecture optimizes the performance on multiple time scalesreactive level (regulation to temperature set points), tactical level (adaptation of temperature set points), and strategic level (trading off fatigue life due to thermal cycling and current production). This controller unique to CSP plants operating at temperatures greater than 550 °C, will make CSPs competitive with conventional power plants and contribute significantly towards the Sunshot goal of 0.06/kWh(e), while responding with agility to both market dynamics and changes in solar irradiance such as due to passing clouds. Moreover, our development of control software with performance guarantees will avoid early stage failures and permit smooth grid integration of the CSP power plants. The proposed controller can be implemented with existing control hardware infrastructure with little or no additional equipment. In the thesis, we demonstrate a dynamics model of CSP, of which different components are modelled with different time scales. We also show a real time control strategy of CSP control oriented model in steady state. Furthermore, we shown different controllers

  16. Integrated dynamic analysis simulation of space stations with controllable solar array

    NASA Technical Reports Server (NTRS)

    Heinrichs, J. A.; Fee, J. J.

    1972-01-01

    A methodology is formulated and presented for the integrated structural dynamic analysis of space stations with controllable solar arrays and non-controllable appendages. The structural system flexibility characteristics are considered in the dynamic analysis by a synthesis technique whereby free-free space station modal coordinates and cantilever appendage coordinates are inertially coupled. A digital simulation of this analysis method is described and verified by comparison of interaction load solutions with other methods of solution. Motion equations are simulated for both the zero gravity and artificial gravity (spinning) orbital conditions. Closed loop controlling dynamics for both orientation control of the arrays and attitude control of the space station are provided in the simulation by various generic types of controlling systems. The capability of the simulation as a design tool is demonstrated by utilizing typical space station and solar array structural representations and a specific structural perturbing force. Response and interaction load solutions are presented for this structural configuration and indicate the importance of using an integrated type analysis for the predictions of structural interactions.

  17. Formation control of multi-robots for on-orbit assembly of large solar sails

    NASA Astrophysics Data System (ADS)

    Hu, Quan; Zhang, Yao; Zhang, Jingrui; Hu, Haiyan

    2016-06-01

    This study focuses on the formation control of four robots used for the on-orbit construction of a large solar sail. The solar sail under consideration is non-spinning and has a 1 km2 area. It includes a hub as the central body and four large booms supporting the lightweight films. Four formation operating space robots capable of walking on the boom structure are utilized to deploy the sail films. Because of the large size and mass of the sail, the robots should remain in formation during the sail deployment to avoid dramatic changes in the system properties. In this paper, the formation control issue of the four robots is solved by an adaptive sliding mode controller. A disturbance observer with finite-time convergence is embedded to improve the control performance. The proposed controller is capable of resisting the strong uncertainties in the operation and do not require the accurate parameters of the system. The stability is proven, and numerical simulations are provided to validate the effectiveness of the control strategy.

  18. Solar Sail Attitude Control System for the NASA Near Earth Asteroid Scout Mission

    NASA Technical Reports Server (NTRS)

    Orphee, Juan; Diedrich, Ben; Stiltner, Brandon; Becker, Chris; Heaton, Andrew

    2017-01-01

    An Attitude Control System (ACS) has been developed for the NASA Near Earth Asteroid (NEA) Scout mission. The NEA Scout spacecraft is a 6U cubesat with an eighty-six square meter solar sail for primary propulsion that will launch as a secondary payload on the Space Launch System (SLS) Exploration Mission 1 (EM-1) and rendezvous with a target asteroid after a two year journey, and will conduct science imagery. The spacecraft ACS consists of three major actuating subsystems: a Reaction Wheel (RW) control system, a Reaction Control System (RCS), and an Active Mass Translator (AMT) system. The reaction wheels allow fine pointing and higher rates with low mass actuators to meet the science, communication, and trajectory guidance requirements. The Momentum Management System (MMS) keeps the speed of the wheels within their operating margins using a combination of solar torque and the RCS. The AMT is used to adjust the sign and magnitude of the solar torque to manage pitch and yaw momentum. The RCS is used for initial de-tumble, performing a Trajectory Correction Maneuver (TCM), and performing momentum management about the roll axis. The NEA Scout ACS is able to meet all mission requirements including attitude hold, slews, pointing for optical navigation and pointing for science with margin and including flexible body effects. Here we discuss the challenges and solutions of meeting NEA Scout mission requirements for the ACS design, and present a novel implementation of managing the spacecraft Center of Mass (CM) to trim the solar sail disturbance torque. The ACS we have developed has an applicability to a range of potential missions and does so in a much smaller volume than is traditional for deep space missions beyond Earth.

  19. Solar absorptance and thermal emittance of some common spacecraft thermal-control coatings

    NASA Technical Reports Server (NTRS)

    Henninger, J. H.

    1984-01-01

    Solar absorptance and thermal emittance of spacecraft materials are critical parameters in determining spacecraft temperature control. Because thickness, surface preparation, coatings formulation, manufacturing techniques, etc. affect these parameters, it is usually necessary to measure the absorptance and emittance of materials before they are used. Absorptance and emittance data for many common types of thermal control coatings, are together with some sample spectral data curves of absorptance. In some cases for which ultraviolet and particle radiation data are available, the degraded absorptance and emittance values are also listed.

  20. Optimal control study for the Space Station Solar Dynamic power module

    NASA Technical Reports Server (NTRS)

    Papadopoulos, P. M.; Laub, A. J.; Kenney, C. S.; Pandey, P.; Ianculescu, G.; Ly, J.

    1991-01-01

    The authors present the design of an optimal control system for the Space Station Freedom's Solar Dynamic Fine Pointing and Tracking (SDFPT) module. A very large state model of six rigid body modes and 272 flexible modes is used in conjunction with classical LQG optimal control to produce a full-order controller which satisfies the requirements. The results obtained are compared with those of a classically designed PID (proportional plus integral plus derivative) controller that was implemented for a six-rigid-body-mode forty-flexible-mode model. A major difficulty with designing LQG controllers for large models is solving the Riccati equation that arises from the optimal formulation. A Riccati solver based on a Pade approximation to the matrix sign function is used. A symmetric version of this algorithm is derived for the special class of Hamiltonion matrices, thereby yielding, for large problems, a nearly twofold speed increase over a previous algorithm.

  1. Consecutive Morphology Controlling Operations for Highly Reproducible Mesostructured Perovskite Solar Cells.

    PubMed

    Wu, Yongzhen; Chen, Wei; Yue, Youfeng; Liu, Jian; Bi, Enbing; Yang, Xudong; Islam, Ashraful; Han, Liyuan

    2015-09-23

    Perovskite solar cells have shown high photovoltaic performance but suffer from low reproducibility, which is mainly caused by low uniformity of the active perovskite layer in the devices. The nonuniform perovskites further limit the fabrication of large size solar cells. In this work, we control the morphology of CH3NH3PbI3 on a mesoporous TiO2 substrate by employing consecutive antisolvent dripping and solvent-vapor fumigation during spin coating of the precursor solution. The solvent-vapor treatment is found to enhance the perovskite pore filling and increase the uniformity of CH3NH3PbI3 in the porous scaffold layer but slightly decrease the uniformity of the perovskite capping layer. An additional antisolvent dripping is employed to recover the uniform perovskite capping layer. Such consecutive morphology controlling operations lead to highly uniform perovskite in both porous and capping layers. By using the optimized perovskite deposition procedure, the reproducibility of mesostructured solar cells was greatly improved such that a total of 40 devices showed an average efficiency of 15.3% with a very small standard deviation of 0.32. Moreover, a high efficiency of 14.9% was achieved on a large-size cell with a working area of 1.02 cm(2).

  2. Effects of Solar Array Shadowing on the Power Capability of the Interim Control Module

    NASA Technical Reports Server (NTRS)

    Fincannon, James; Hojnicki, Jeffrey S.; Garner, James Christopher

    1999-01-01

    The Interim Control Module (ICM) is being built by the US Naval Research Laboratory (NRL) for NASA as a propulsion module for the International Space Station (ISS). Originally developed as a spinning spacecraft used to move payloads to their final orbit, for ISS, the ICM will be in a fixed orientation and location for long periods resulting in substantial solar panel shadowing. This paper describes the methods used to determine the incident energy incident energy on the ICM solar panels and the power capability of the electric power system (EPS). Applying this methodology has resulted in analyses and assessments used to identify ICM early design changes/options, placement and orientations that enable successful operation of the EPS under a wide variety of anticipated conditions.

  3. Controlling the conduction band offset for highly efficient ZnO nanorods based perovskite solar cell

    NASA Astrophysics Data System (ADS)

    Dong, Juan; Shi, Jiangjian; Li, Dongmei; Luo, Yanhong; Meng, Qingbo

    2015-08-01

    The mechanism of charge recombination at the interface of n-type electron transport layer (n-ETL) and perovskite absorber on the carrier properties in the perovskite solar cell is theoretically studied. By solving the one dimensional diffusion equation with different boundary conditions, it reveals that the interface charge recombination in the perovskite solar cell can be suppressed by adjusting the conduction band offset (ΔEC) at ZnO ETL/perovskite absorber interface, thus leading to improvements in cell performance. Furthermore, Mg doped ZnO nanorods ETL has been designed to control the energy band levels. By optimizing the doping amount of Mg, the conduction band minimum of the Mg doped ZnO ETL has been raised up by 0.29 eV and a positive ΔEC of about 0.1 eV is obtained. The photovoltage of the cell is thus significantly increased due to the relatively low charge recombination.

  4. Attitude control requirements for an earth-orbital solar electric propulsion stage

    NASA Technical Reports Server (NTRS)

    Oglevie, R. E.; Andrews, P. D.; Jasper, T. P.

    1975-01-01

    Solar Electric Propulsion Stage (SEPS) application in earth orbit requires considerably more maneuvering for thrust vector steering and solar array pointing than planetary missions. Attitude maneuver requirements for geosynchronous and low earth-orbital missions are presented. Situations which result in optimum steering torque requirements exceeding the capability of current SEPS configurations are defined. Sub-optimal steering techniques are defined which reduce the geosynchronous mission torque requirements to acceptable levels with negligible performance penalties. Some low earth-orbital flight regimes with earth shadowing are found to result in much larger torque requirements and impose significant mechanization penalties if serious performance losses are to be avoided. Alternative attitude control mechanization techniques are defined for these cases.

  5. Solar disinfection of drinking water and diarrhoea in Maasai children: a controlled field trial.

    PubMed

    Conroy, R M; Elmore-Meegan, M; Joyce, T; McGuigan, K G; Barnes, J

    During December 1995-March 1996 in Kajiado Province, Kenya, 206 Maasai children, 5-16 years old, whose drinking water was contaminated with fecal coliform bacteria, were assigned 1.5 liter plastic bottles in which to store their drinking water. These bottles were re-used commercial table water bottles. The families of the children had only community sources for drinking water: 2 open water-holes and 1 tank fed from a piped supply. These water sources were not suited to chlorination. Scarce fuel and indoor air pollution precluded boiling water inside the hut. In the presence of their mothers, 108 children (the solar group) were told to fill the bottles with water at dawn, leave them in full sunlight on the roofs of their homes, and wait until midday before drinking from the bottles. The remaining 98 children (the control group) were told to leave the bottles in their homes. The purpose of the study was to evaluate the effect of solar disinfection on diarrheal disease in these Maasai children. Over a 12-week period, children in the solar group suffered fewer diarrhea episodes than those in the control group (4.1 vs. 4.5; adjusted odds ratio [AOR] = 0.66). They also were less likely to have diarrhea episodes severe enough to prevent them from doing their chores (1.7 vs. 2.3; AOR = 0.65). These findings suggest that solar disinfection of water may reduce diarrhea in communities with no access to other means of disinfection.

  6. LabVIEW-based control software for para-hydrogen induced polarization instrumentation

    SciTech Connect

    Agraz, Jose Grunfeld, Alexander; Li, Debiao; Cunningham, Karl; Willey, Cindy; Pozos, Robert; Wagner, Shawn

    2014-04-15

    The elucidation of cell metabolic mechanisms is the modern underpinning of the diagnosis, treatment, and in some cases the prevention of disease. Para-Hydrogen induced polarization (PHIP) enhances magnetic resonance imaging (MRI) signals over 10 000 fold, allowing for the MRI of cell metabolic mechanisms. This signal enhancement is the result of hyperpolarizing endogenous substances used as contrast agents during imaging. PHIP instrumentation hyperpolarizes Carbon-13 ({sup 13}C) based substances using a process requiring control of a number of factors: chemical reaction timing, gas flow, monitoring of a static magnetic field (B{sub o}), radio frequency (RF) irradiation timing, reaction temperature, and gas pressures. Current PHIP instruments manually control the hyperpolarization process resulting in the lack of the precise control of factors listed above, resulting in non-reproducible results. We discuss the design and implementation of a LabVIEW based computer program that automatically and precisely controls the delivery and manipulation of gases and samples, monitoring gas pressures, environmental temperature, and RF sample irradiation. We show that the automated control over the hyperpolarization process results in the hyperpolarization of hydroxyethylpropionate. The implementation of this software provides the fast prototyping of PHIP instrumentation for the evaluation of a myriad of {sup 13}C based endogenous contrast agents used in molecular imaging.

  7. LabVIEW-based control software for para-hydrogen induced polarization instrumentation.

    PubMed

    Agraz, Jose; Grunfeld, Alexander; Li, Debiao; Cunningham, Karl; Willey, Cindy; Pozos, Robert; Wagner, Shawn

    2014-04-01

    The elucidation of cell metabolic mechanisms is the modern underpinning of the diagnosis, treatment, and in some cases the prevention of disease. Para-Hydrogen induced polarization (PHIP) enhances magnetic resonance imaging (MRI) signals over 10,000 fold, allowing for the MRI of cell metabolic mechanisms. This signal enhancement is the result of hyperpolarizing endogenous substances used as contrast agents during imaging. PHIP instrumentation hyperpolarizes Carbon-13 ((13)C) based substances using a process requiring control of a number of factors: chemical reaction timing, gas flow, monitoring of a static magnetic field (Bo), radio frequency (RF) irradiation timing, reaction temperature, and gas pressures. Current PHIP instruments manually control the hyperpolarization process resulting in the lack of the precise control of factors listed above, resulting in non-reproducible results. We discuss the design and implementation of a LabVIEW based computer program that automatically and precisely controls the delivery and manipulation of gases and samples, monitoring gas pressures, environmental temperature, and RF sample irradiation. We show that the automated control over the hyperpolarization process results in the hyperpolarization of hydroxyethylpropionate. The implementation of this software provides the fast prototyping of PHIP instrumentation for the evaluation of a myriad of (13)C based endogenous contrast agents used in molecular imaging.

  8. LabVIEW-based control software for para-hydrogen induced polarization instrumentation

    NASA Astrophysics Data System (ADS)

    Agraz, Jose; Grunfeld, Alexander; Li, Debiao; Cunningham, Karl; Willey, Cindy; Pozos, Robert; Wagner, Shawn

    2014-04-01

    The elucidation of cell metabolic mechanisms is the modern underpinning of the diagnosis, treatment, and in some cases the prevention of disease. Para-Hydrogen induced polarization (PHIP) enhances magnetic resonance imaging (MRI) signals over 10 000 fold, allowing for the MRI of cell metabolic mechanisms. This signal enhancement is the result of hyperpolarizing endogenous substances used as contrast agents during imaging. PHIP instrumentation hyperpolarizes Carbon-13 (13C) based substances using a process requiring control of a number of factors: chemical reaction timing, gas flow, monitoring of a static magnetic field (Bo), radio frequency (RF) irradiation timing, reaction temperature, and gas pressures. Current PHIP instruments manually control the hyperpolarization process resulting in the lack of the precise control of factors listed above, resulting in non-reproducible results. We discuss the design and implementation of a LabVIEW based computer program that automatically and precisely controls the delivery and manipulation of gases and samples, monitoring gas pressures, environmental temperature, and RF sample irradiation. We show that the automated control over the hyperpolarization process results in the hyperpolarization of hydroxyethylpropionate. The implementation of this software provides the fast prototyping of PHIP instrumentation for the evaluation of a myriad of 13C based endogenous contrast agents used in molecular imaging.

  9. An investigation of quasi-inertial attitude control for a solar power satellite

    NASA Technical Reports Server (NTRS)

    Juang, J.-N.; Wang, S. J.

    1982-01-01

    An efficient means, a quasi-inertial attitude mode, is developed for maintaining the normal solar orientation of a space satellite for power collection in a synchronous orbit. Formulae are presented which establish the basic parametric properties for ideal quasi-inertial attitude and phasing. An active control system is necessary to compensate for the energy loss since energy dissipation in widely oscillating flexible bodies produces an instability of the quasi-inertial attitude in the sense that the spacecraft will tumble at the orbit rate. A fixed terminal time and state optimal control problem is formulated and an algorithm for determining the optimal control as a means for the periodical attitude and phase compensation is developed. The vehicle orientation affected by internal disturbance (structural flexibility) and external disturbances (e.g., drag forces) is maintained by a specialized controller design.

  10. Study of a 30-M Boom For Solar Sail-Craft: Model Extendibility and Control Strategy

    NASA Technical Reports Server (NTRS)

    Keel, Leehyun

    2005-01-01

    extendibility question of the analytical models. In operation, rapid temperature changes can be induced in solar sails as they transition from day to night and vice versa. This generates time dependent thermally induced forces, which may in turn create oscillation in structural members such as booms. Such oscillations have an adverse effect on system operations, precise pointing of instruments and antennas and can lead to self excited vibrations of increasing amplitude. The latter phenomenon is known as thermal flutter and can lead to the catastrophic failure of structural systems. To remedy this problem, an active vibration suppression system has been developed. It was shown that piezoelectric actuators used in conjunction with a Proportional Feedback Control (PFC) law (or Velocity Feedback Control (VFC) law) can induce moments that can suppress structural vibrations and prevent flutter instability in spacecraft booms. In this study, we will investigate control strategies using piezoelectric transducers in active, passive, and/or hybrid control configurations. Advantages and disadvantages of each configuration will be studied and experiments to determine their capabilities and limitations will be planned. In particular, special attention will be given to the hybrid control, also known as energy recycling, configuration due to its unique characteristics.

  11. Telescopio prototipo complementario de HASTA para observaciones de la cromósfera y fotósfera solares

    NASA Astrophysics Data System (ADS)

    Francile, C.; Luoni, M. L.; López, C. E.; Castro, J. I.; Costa, A.

    2016-08-01

    We report the design of a prototype refractor telescope oriented to complement the functionality of the H-Alpha Solar Telescope for Argentine (HASTA). It will allow to make photospheric observations in white light and chromospheric ones in the most intense lines, such as Ca ii K. This new instrument will observe the full solar disk or into regions of interest with a maximum pixel spatial-resolution of 0.57, and will allow the study of the sunspots, the faculae, the evolution of active regions and sporadically the most energetic flares in white light by utilizing high speed image acquisition cadences and exposure times of 1--5 ms.

  12. Solvent engineering towards controlled grain growth in perovskite planar heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Rong, Yaoguang; Tang, Zhongjia; Zhao, Yufeng; Zhong, Xin; Venkatesan, Swaminathan; Graham, Harrison; Patton, Matthew; Jing, Yan; Guloy, Arnold M.; Yao, Yan

    2015-06-01

    We report an effective solvent engineering process to enable controlled perovskite crystal growth and a wider window for processing uniform and dense methyl ammonium lead iodide (MAPbI3) perovskite films. Planar heterojunction solar cells fabricated with this method demonstrate hysteresis-free performance with a power conversion efficiency around 10%. The crystal structure of an organic-based Pb iodide intermediate phase is identified for the first time, which is critical in controlling the crystal growth and optimizing thin film morphology.We report an effective solvent engineering process to enable controlled perovskite crystal growth and a wider window for processing uniform and dense methyl ammonium lead iodide (MAPbI3) perovskite films. Planar heterojunction solar cells fabricated with this method demonstrate hysteresis-free performance with a power conversion efficiency around 10%. The crystal structure of an organic-based Pb iodide intermediate phase is identified for the first time, which is critical in controlling the crystal growth and optimizing thin film morphology. Electronic supplementary information (ESI) available: Detailed Experimental methods; photovoltaic performance of the devices; An X-ray crystallographic file (CIF). See DOI: 10.1039/c5nr02866c

  13. Solar array pointing control for the International Space Station electrical power subsystem to optimize power delivery

    SciTech Connect

    Hill, R.C.

    1998-07-01

    Precise orientation control of the International Space Station (ISS) Electrical Power System (EPS) photovoltaic (PV) solar arrays is required for a number of reasons, including the optimization of power delivery to ISS system loads and payloads. To maximize power generation and delivery in general, the PV arrays are pointed directly at the sun with some allowance for inaccuracies in determination of where to point and in the actuation of pointing the PV arrays. Control of PV array orientation in this sun pointing mode is performed automatically by onboard hardware and software. During certain conditions, maximum power cannot be generated in automatic sun tracking mode due to shadowing of the PV arrays cast by other ISS structures, primarily adjacent PV arrays. In order to maximize the power generated, the PV arrays must be pointed away from the ideal sun pointing targets to reduce the amount of shadowing. The amount of off-pointing to maximize power is a function of many parameters such as the physical configuration of the ISS structures during the assembly timeframe, the solar beta angle and vehicle attitude. Thus the off-pointing cannot be controlled automatically and must be determined by ground operators. This paper presents an overview of ISS PV array orientation control, PV array power performance under shadowed and off-pointing conditions, and a methodology to maximize power under those same conditions.

  14. Fault Detection and Correction for the Solar Dynamics Observatory Attitude Control System

    NASA Technical Reports Server (NTRS)

    Starin, Scott R.; Vess, Melissa F.; Kenney, Thomas M.; Maldonado, Manuel D.; Morgenstern, Wendy M.

    2007-01-01

    The Solar Dynamics Observatory is an Explorer-class mission that will launch in early 2009. The spacecraft will operate in a geosynchronous orbit, sending data 24 hours a day to a devoted ground station in White Sands, New Mexico. It will carry a suite of instruments designed to observe the Sun in multiple wavelengths at unprecedented resolution. The Atmospheric Imaging Assembly includes four telescopes with focal plane CCDs that can image the full solar disk in four different visible wavelengths. The Extreme-ultraviolet Variability Experiment will collect time-correlated data on the activity of the Sun's corona. The Helioseismic and Magnetic Imager will enable study of pressure waves moving through the body of the Sun. The attitude control system on Solar Dynamics Observatory is responsible for four main phases of activity. The physical safety of the spacecraft after separation must be guaranteed. Fine attitude determination and control must be sufficient for instrument calibration maneuvers. The mission science mode requires 2-arcsecond control according to error signals provided by guide telescopes on the Atmospheric Imaging Assembly, one of the three instruments to be carried. Lastly, accurate execution of linear and angular momentum changes to the spacecraft must be provided for momentum management and orbit maintenance. In thsp aper, single-fault tolerant fault detection and correction of the Solar Dynamics Observatory attitude control system is described. The attitude control hardware suite for the mission is catalogued, with special attention to redundancy at the hardware level. Four reaction wheels are used where any three are satisfactory. Four pairs of redundant thrusters are employed for orbit change maneuvers and momentum management. Three two-axis gyroscopes provide full redundancy for rate sensing. A digital Sun sensor and two autonomous star trackers provide two-out-of-three redundancy for fine attitude determination. The use of software to maximize

  15. AOCS Performance and Stability Validation for a 160-m Solar Sail with Control-Structure Interactions

    NASA Technical Reports Server (NTRS)

    Wie, Bong; Murphy, David

    2005-01-01

    Future solar sail missions, such as NASA's Solar Polar Imager Vision, will require sails with dimensions on the order of 50-500 m. We are examining a square sail design with moving mass (trim control mass, TCM) and quadrant rotation primary actuators plus pulsed plasma thrusters (PPTs) at the mast tips for backup attitude control. Quadrant rotation is achieved via roll stabilizer bars (RSB) at the mast tips. At these sizes, given the gossamer nature of the sail supporting structures, flexible modes may be low enough to interact with the control system, especially as these actuators are located on the flexible structure itself and not on the rigid core. This paper develops a practical analysis of the flexible interactions using state-space systems and modal data from finite element models of the system. Torsion and bending of the masts during maneuvers could significantly affect the function of the actuators while activation of the membrane modes could adversely affect the thrust vector direction and magnitude. Analysis of the RSB and TCM dynamics for developing high-fidelity simulations is included. For control analysis of the flexible system, standard finite-element models of the flexible sail body are loaded and the modal data is used to create a modal coordinate state-space system. Key parameters include which modes to include, which nodes are of interest for force inputs and displacement outputs, connecting nodes through which external forces and torques are applied from the flex body to the core, any nominal momentum in the system, and any steady rates. The system is linearized about the nominal attitude and rate. The state-space plant can then be analyzed with a state-space controller, and Bode, Nyquist, step and impulse responses generated. The approach is general for any rigid core with a flexible appendage. This paper develops a compensator for a simple two-mass flex system and extrapolates the results to the solar sail. A finite element model of the 20 m

  16. Nanomorphology control and novel materials studies in polymer/fullerene bulk heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Yao, Yan

    This dissertation focuses on improving the efficiency of polymer/fullerene bulk heterojunction solar cells from two directions: (i) understanding the nanomorphology-efficiency relationship and controlling the active layer morphology during its formation; (ii) developing new materials for both electron donors and electron acceptors in the polymer solar cells. A solvent annealing approach is successfully demonstrated to control the morphology and increase device efficiency in poly(3-hexylthiophene):fullerene solar cells. A detailed evolution study on this approach using absorption, photoluminescence, external quantum efficiency, atomic force microscopy, and grazing incidence X-ray diffraction techniques leads to following understanding: the optimum nanomorphology must be a balance between large interfacial area for exciton dissociation and continuous pathways for carrier transportation. 4.4% efficiency is demonstrated in this system. Effects of solvent mixture on the nanoscale phase separation are studied further. The donor/acceptor components in the active layer can "intelligently" phase separate into an optimum morphology during the spin-coating process and no further treatment is necessary. Devices with the solvent mixture show about 10 times higher efficiency compared to those devices fabricated without the additive solvent fabricated under the same condition. A model and additive solvent selection rule are proposed to explain the phenomenon. To address the absorption mismatch with solar spectrum, two novel low band gap copolymers containing 3-alkoxythiophene have been synthesized with the band gap of 1.64 and 1.77 eV, respectively. In addition, novel electron acceptors also hold great promise. A 50% increase in short-circuit current is demonstrated by using (6,6)-phenyl-C71-butyric acid methyl ester (C70-PCBM) to replace (6,6)-phenyl-C61-butyric acid methyl ester (PCBM). As the result, 2.4% power conversion efficiency is achieved for low band gap polymer based

  17. Controlling Charging and Arcing on a Solar Powered Auroral Orbiting Spacecraft

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.; Rhee, Michael S.

    2008-01-01

    The Global Precipitation Measurement satellite (GPM) will be launched into a high inclination (65 degree) orbit to monitor rainfall on a global scale. Satellites in high inclination orbits have been shown to charge to high negative potentials, with the possibility of arcing on the solar arrays, when three conditions are met: a drop in plasma density below approximately 10,000 cm(exp -3), an injection of energetic electrons of energy more that 7-10 keV, and passage through darkness. Since all of these conditions are expected to obtain for some of the GPM orbits, charging calculations were done using first the Space Environment and Effects (SEE) Program Interactive Spacecraft Charging Handbook, and secondly the NASA Air-force Spacecraft Charging Analyzer Program (NASCAP-2k). The object of the calculations was to determine if charging was likely for the GPM configuration and materials, and specifically to see if choosing a particular type of thermal white paint would help minimize charging. A detailed NASCAP-2k geometrical model of the GPM spacecraft was built, with such a large number of nodes that it challenged the capability of NASCAP-2k to do the calculations. The results of the calculations were that for worst-case auroral charging conditions, charging to levels on the order of -120 to -230 volts could occur on GPM during night-time, with differential voltages on the solar arrays that might lead to solar array arcing. In sunlit conditions, charging did not exceed -20 V under any conditions. The night-time results were sensitive to the spacecraft surface materials chosen. For non-conducting white paints, the charging was severe, and could continue unabated throughout the passage of GPM through the auroral zone. Somewhat conductive (dissipative) white paints minimized the night-time charging to levels of -120 V or less, and thus were recommended for GPM thermal control. It is shown that the choice of thermal control paints is important to prevent arcing on high

  18. Quantum dynamical simulations for nuclear spin selective laser control of ortho- and para-fulvene.

    PubMed

    Belz, S; Grohmann, T; Leibscher, M

    2009-07-21

    In the present paper we explore the prospects for laser control of the photoinduced nonadiabatic dynamics of para- and ortho-fulvene with the help of quantum dynamical simulations. Previous investigations [Bearpark et al., J. Am. Chem. Soc. 118, 5253 (1996); Alfalah et al., J. Chem. Phys. 130, 124318 (2009)] show that photoisomerization of fulvene is hindered by ultrafast radiationless decay through a conical intersection at planar configuration. Here, we demonstrate that photoisomerization can nevertheless be initiated by damping unfavorable nuclear vibrations with properly designed laser pulses. Moreover, we show that the resulting intramolecular torsion is nuclear spin selective. The selectivity of the photoexcitation with respect to the nuclear spin isomers can be further enhanced by applying an optimized sequence of two laser pulses.

  19. Fuzzy Rule Suram for Control System of a Solar Energy Wood Drying Chamber

    NASA Astrophysics Data System (ADS)

    Situmorang, Zakarias; Wardoyo, Retantyo; Hartati, Sri; Eko Istiyanto, Jazi

    2009-08-01

    The paper reports used the fuzzy rule Suram for control system of a wood drying chamber with solar as source of energy. Rule suram based of fuzzy logic with variables of weather is temperature ambient and conditions of air is humidity ambient, it implemented for wood drying process. The membership function of variable of state represented in error value and change error with typical of triangle and trapezium map. Result of Analysis to reach 8 fuzzy rule to control the output system can be constructed in a number of way of weather and conditions of air. It used to minimum of the consumption of electric energy by heater. The rule suram used to stability and equilibrium of schedule of drying in chamber by control of temperature and humidity. The result of implemented of fuzzy rule suram with the modification of membership function in range [0.5, 1] represented approximate to he conditions riel.

  20. Software control of the Advanced Technology Solar Telescope enclosure PLC hardware using COTS software

    NASA Astrophysics Data System (ADS)

    Borrowman, Alastair J.; de Bilbao, Lander; Ariño, Javier; Murga, Gaizka; Goodrich, Bret; Hubbard, John R.; Greer, Alan; Mayer, Chris; Taylor, Philip

    2012-09-01

    As PLCs evolve from simple logic controllers into more capable Programmable Automation Controllers (PACs), observatories are increasingly using such devices to control complex mechanisms1, 2. This paper describes use of COTS software to control such hardware using the Advanced Technology Solar Telescope (ATST) Common Services Framework (CSF). We present the Enclosure Control System (ECS) under development in Spain and the UK. The paper details selection of the commercial PLC communication library PLCIO. Implemented in C and delivered with source code, the library separates the programmer from communication details through a simple API. Capable of communicating with many types of PLCs (including Allen-Bradley and Siemens) the API remains the same irrespective of PLC in use. The ECS is implemented in Java using the observatory's framework that provides common services for software components. We present a design following a connection-based approach where all components access the PLC through a single connection class. The link between Java and PLCIO C library is provided by a thin Java Native Interface (JNI) layer. Also presented is a software simulator of the PLC based upon the PLCIO Virtual PLC. This creates a simulator operating below the library's API and thus requires no change to ECS software. It also provides enhanced software testing capabilities prior to hardware becoming available. Results are presented in the form of communication timing test data, showing that the use of CSF, JNI and PLCIO provide a control system capable of controlling enclosure tracking mechanisms, that would be equally valid for telescope mount control.

  1. The dynamics and control of solar-sail spacecraft in displaced lunar orbits

    NASA Astrophysics Data System (ADS)

    Wawrzyniak, Geoffrey George

    structure of the solution space is not well known. Because of their simplicity and speed, the FDM is used to populate a survey to assist in the understanding of the available design space. Trajectories generated by FDMs can also be used to initialize other nonlinear BVP solvers. Any solution is only as accurate as the model used to generate it, especially when the trajectory is dynamically unstable, certainly the case when an orbit is purposefully offset from the Moon. Perturbations, such as unmodeled gravitational forces, variations in the solar flux, as well as mis-modeling of the sail and bus properties, all shift the spacecraft off the reference trajectory and, potentially, into a regime from which the vehicle is unrecoverable. Therefore, some type of flight-path control is required to maintain the vehicle near the reference path. Reference trajectories, supplied by FDMs, are used to develop guidance algorithms based on other, more accurate, numerical procedures, such as multiple shooting. The primary motivation of this investigation is to determine what level of technology is required to displace a solar sail spacecraft sufficiently such that a vehicle equipped with a sail supplies a continuous relay between the Earth and an outpost at the lunar south pole. To accomplish this objective, numerical methods to generate reference orbits that meet mission constraints are examined, as well as flight-path control strategies to ensure that a sailcraft follows those reference trajectories. A survey of the design space is also performed to highlight vehicle-performance and ground-based metrics critical to a mission that monitors the lunar south pole at all times. Finally, observations about the underlying dynamical structure of solar sail motion in a multi-body system are summarized.

  2. Design of the support structure, drive pedestal, and controls for a solar concentrator

    NASA Astrophysics Data System (ADS)

    Goldberg, V. R.; Ford, J. L.; Anderson, A. E.

    1991-08-01

    The glass/metal McDonnell-Douglas dish is the state-of-the-art of parabolic dish concentrators. Because of the perceived high production cost of this concentrator, the Department of Energy's Solar Thermal Program is developing stretch membrane technology for large (75 kWt) solar concentrators for integration with receivers and engines in 25 kWe dish-Stirling systems. The objective of this development effort is to reduce the cost of the concentrator while maintaining the high levels of performance characteristic of glass-metal dishes. Under contract to Sandia National Laboratories, Science Applications International Corporation, Solar Kinetics Inc. and WG Associates are developing a faceted stretched-membrane heliostat technology. This design will result in a low-risk, near-term concentrator for dish-Stirling systems. WG Associates has designed the support structure, drives and tracking controls for this dish. The structure is configured to support 12 stretched-membrane, 3.5-meter diameter facets in a shaped dish configuration. The dish design is sized to power a dish-Stirling system capable of producing 25 kW (electric). In the design of the structure, trade-off studies were conducted to determine the best facet arrangement, dish contour, dish focal length, tracking control and walk-off protection. As part of the design, in-depth analyses were performed to evaluate pointing accuracy, compliance with AISC steel design codes, and the economics of fabrication and installation. Detailed fabrication and installation drawings were produced, and initial production cost estimates for the dish were developed. These issues, and the final dish design, are presented in this report.

  3. Design of the support structure, drive pedestal, and controls for a solar concentrator

    SciTech Connect

    Goldberg, V.R.; Ford, J.L.; Anderson, A.E. )

    1991-08-01

    The glass/metal McDonnell-Douglas dish is the state-of-the-art of parabolic dish concentrators. Because of the perceived high production cost of this concentrator, the Department of Energy's Solar Thermal Program is developing stretch-membrane technology for large (75 kWt) solar concentrators for integration with receivers and engines in 25 kWe dish-Stirling systems. The objective of this development effort is to reduce the cost of the concentrator while maintaining the high levels of performance characteristic of glass-metal dishes. Under contract to Sandia National Laboratories, Science Applications International Corporation, Solar Kinetics Inc. and WG Associates are developing a faceted stretched-membrane heliostat technology. This design will result in a low-risk, near-term concentrator for dish-Stirling systems. WG Associates has designed the support structure, drives and tracking controls for this dish. The structure is configured to support 12 stretched-membrane, 3.5-meter diameter facets in a shaped dish configuration. The dish design is sized to power a dish-Stirling system capable of producing 25 kW (electric). In the design of the structure, trade-off studies were conducted to determine the best'' facet arrangement, dish contour, dish focal length, tracking control and walk-off protection. As part of the design, in-depth analyses were performed to evaluate pointing accuracy, compliance with AISC steel design codes, and the economics of fabrication and installation. Detailed fabrication and installation drawings were produced, and initial production cost estimates for the dish were developed. These issues, and the final dish design, are presented in this report. 7 refs., 33 figs., 18 tabs.

  4. Displaced orbits for solar sail equipped with reflectance control devices in Hill's restricted three-body problem with oblateness

    NASA Astrophysics Data System (ADS)

    Song, Ming; He, Xingsuo; He, Dongsheng

    2016-10-01

    We investigate solar sail displaced orbits in the Hill's restricted three-body problem, where the larger primary is an oblate spheroid in the system. Firstly, the model of solar sail equipped with a new version of reflectance control device is introduced. Next, dynamical model of the system with the larger primary an oblate spheroid is established and the Hill's restricted three-body problem with oblateness is built through appropriate simplifications. The collinear equilibrium points of the Hill's system varying with the variations of areas of absorption and thermal radiation of reflectance control devices in the solar sail, or the dimensionless characteristic acceleration of solar sail, or the oblateness of the larger primary are also investigated. Then, Linearization near the collinear equilibria of the system is applied. A linear quadratic regulator is used to stabilize the nonlinear system. The simulation reveals that solar sail displaced orbits in this system are doable and asymptotically stable by means of adjusting the pitch angle of solar sail and the area of absorption in reflectance control devices.

  5. Solar Sail Spaceflight Simulation

    NASA Technical Reports Server (NTRS)

    Lisano, Michael; Evans, James; Ellis, Jordan; Schimmels, John; Roberts, Timothy; Rios-Reyes, Leonel; Scheeres, Daniel; Bladt, Jeff; Lawrence, Dale; Piggott, Scott

    2007-01-01

    The Solar Sail Spaceflight Simulation Software (S5) toolkit provides solar-sail designers with an integrated environment for designing optimal solar-sail trajectories, and then studying the attitude dynamics/control, navigation, and trajectory control/correction of sails during realistic mission simulations. Unique features include a high-fidelity solar radiation pressure model suitable for arbitrarily-shaped solar sails, a solar-sail trajectory optimizer, capability to develop solar-sail navigation filter simulations, solar-sail attitude control models, and solar-sail high-fidelity force models.

  6. Space Solar Power Multi-body Dynamics and Controls, Concepts for the Integrated Symmetrical Concentrator Configuration

    NASA Technical Reports Server (NTRS)

    Glaese, John R.; McDonald, Emmett J.

    2000-01-01

    Orbiting space solar power systems are currently being investigated for possible flight in the time frame of 2015-2020 and later. Such space solar power (SSP) satellites are required to be extremely large in order to make practical the process of collection, conversion to microwave radiation, and reconversion to electrical power at earth stations or at remote locations in space. These large structures are expected to be very flexible presenting unique problems associated with their dynamics and control. The purpose of this project is to apply the expanded TREETOPS multi-body dynamics analysis computer simulation program (with expanded capabilities developed in the previous activity) to investigate the control problems associated with the integrated symmetrical concentrator (ISC) conceptual SSP system. SSP satellites are, as noted, large orbital systems having many bodies (perhaps hundreds) with flexible arrays operating in an orbiting environment where the non-uniform gravitational forces may be the major load producers on the structure so that a high fidelity gravity model is required. The current activity arises from our NRA8-23 SERT proposal. Funding, as a supplemental selection, has been provided by NASA with reduced scope from that originally proposed.

  7. A thermal control approach for a solar electric propulsion thrust subsystem

    NASA Technical Reports Server (NTRS)

    Maloy, J. E.; Oglebay, J. C.

    1979-01-01

    A thrust subsystem thermal control design is defined for a Solar Electric Propulsion System (SEPS) proposed for the comet Halley Flyby/comet Tempel 2 rendezvous mission. A 114 node analytic model, developed and coded on the systems improved numerical differencing analyzer program, was employed. A description of the resulting thrust subsystem thermal design is presented as well as a description of the analytic model and comparisons of the predicted temperature profiles for various SEPS thermal configurations that were generated using this model. It was concluded that: (1) a BIMOD engine system thermal design can be autonomous; (2) an independent thrust subsystem thermal design is feasible; (3) the interface module electronics temperatures can be controlled by a passive radiator and supplementary heaters; (4) maintaining heat pipes above the freezing point would require an additional 322 watts of supplementary heating power for the situation where no thrusters are operating; (5) insulation is required around the power processors, and between the interface module and the avionics module, as well as in those areas which may be subjected to solar heating; and (6) insulation behind the heat pipe radiators is not necessary.

  8. Modelizacion, control e implementacion de un procesador energetico paralelo para aplicacion en sistemas multisalida

    NASA Astrophysics Data System (ADS)

    Ferreres Sabater, Agustin

    modelizacion, y aplicacion en convertidores PWM, esta aun por estudiar y valorar. El primer Capitulo consiste en una breve introduccion al problema de la regulacion cruzada y la impedancia cruzada para posteriormente describir las tecnicas de post-regulacion actualmente mas empleadas, con especial atencion al post-regulador con transformador controlado. El Capitulo segundo trata del estudio de las caracteristicas estaticas del postregulador con transformador controlado. Partiendo de los estudios disponibles sobre el postregulador se plantean mejoras en su modo de actuacion y se discuten tres alternativas diferentes para controlar el transformador. Las dos primeras consisten en emplear un convertidor auxiliar Boost en sus dos modos de funcionamiento, continuo y discontinuo. La tercera consiste en controlar el transformador con una tension PWM directamente, sin filtrado. Finalmente se comprueba experimentalmente, para el estado estacionario, el funcionamiento del post-regulador para cada uno de los tres metodos de control. El Capitulo tercero trata de la dinamica de la salida controlada con el post-regulador cuando este emplea un convertidor auxiliar tipo Boost. Mediante la tecnica de promediado de variables de estado se propone el modelo de pequena senal, tanto para el modo continuo como para el modo discontinuo de funcionamiento del convertidor auxiliar. Los resultados mas significativos de esta seccion son las expresiones analiticas de las impedancias cruzadas y de la impedancia de la salida post-regulada. Como complemento al modelo de pequena senal se plantea un modelo de gran senal implementado sobre el simulador Pspice. Con este nuevo modelo se reproducen los resultados obtenidos con el modelo de pequena senal y ademas es posible simular los transitorios en las tensiones de salida ante cambios de carga. La modelizacion del convertidor cuando el transformador se controla con una tension PWM sin filtrar es el objetivo del Capitulo 4. En las secciones siguientes del Capitulo

  9. A ground based phase control system for the solar power satellite. Executive summary, volume 1, phase 3

    NASA Technical Reports Server (NTRS)

    Chie, C. M.

    1980-01-01

    The Solar Power Satellite (SPS) concept and the reference phase control system investigated in earlier efforts are reviewed. A summary overview of the analysis and selection of the pilot signal and power transponder design is presented along with the SOLARSIM program development and the simulated SPS phase control performance. Evaluations of the ground based phase control system as an alternate phase control concept are summarized.

  10. Enhanced photocurrent in thin-film amorphous silicon solar cells via shape controlled three-dimensional nanostructures.

    PubMed

    Hilali, Mohamed M; Yang, Shuqiang; Miller, Mike; Xu, Frank; Banerjee, Sanjay; Sreenivasan, S V

    2012-10-12

    In this paper, we have explored manufacturable approaches to sub-wavelength controlled three-dimensional (3D) nano-patterns with the goal of significantly enhancing the photocurrent in amorphous silicon solar cells. Here we demonstrate efficiency enhancement of about 50% over typical flat a-Si thin-film solar cells, and report an enhancement of 20% in optical absorption over Asahi textured glass by fabricating sub-wavelength nano-patterned a-Si on glass substrates. External quantum efficiency showed superior results for the 3D nano-patterned thin-film solar cells due to enhancement of broadband optical absorption. The results further indicate that this enhanced light trapping is achieved with minimal parasitic absorption losses in the deposited transparent conductive oxide for the nano-patterned substrate thin-film amorphous silicon solar cell configuration. Optical simulations are in good agreement with experimental results, and also show a significant enhancement in optical absorption, quantum efficiency and photocurrent.

  11. Tracking instrument and control for solar concentrators. Final technical report, October 1979-January 1981

    SciTech Connect

    Gray, J; Kuhlman, J

    1981-01-31

    The tracker uses a single photo sensor, and a rotating aperature to obtain tracking accuracies better than 1.5 mrads (0.1 degs). Peak signal detection is used to eliminate tracking of false sources, i.e., clouds, etc. A prism is employed to obtain an extended field of view (150 degs axially - 360 degs radially). The tracker digitally measures the Suns displacement angle relative to the concentrator axis, and repositions it incrementally. This arrangement permits the use of low cost non-servo motors. The local controller contains microprocessor based electronics, incorporating digital signal processing. A single controller may be time shared by a maximum of sixteen trackers, providing a high performance, cost effective solar tracking system, suitable for both line and point focus concentrators. An installation may have the local controller programmed as a standalone unit or slaved to a central controller. When used with a central controller, dynamic data monitoring and logging is available, together with the ability to change system modes and parameters, as desired.

  12. Control of back surface reflectance from aluminum alloyed contacts on silicon solar cells

    SciTech Connect

    Cudzinovic, M.; Sopori, B.

    1996-05-01

    A process for forming highly reflective aluminum back contacts with low contact resistance to silicon solar cells is described. By controlling the process conditions, it is possible to vary the silicon/aluminum interface from a specular to a diffuse reflector while maintaining a high interface reflectance. The specular interface is found to be a uniform silicon/aluminum alloy layer a few angstroms thick that has epitaxially regrown on the silicon. The diffuse interface consists of randomly distributed (111) pyramids produced by crystallographic out-diffusion of the bulk silicon. The light trapping ability of the diffuse contact is found to be close to the theoretical limit. Both types of contacts are found to have specific contact resistivities of 10{sup {minus}5} {Omega}-cm{sup 2}. The process for forming the contacts involves illuminating the devices with tungsten halogen lamps. The process is rapid (under 100 s) and low temperature (peak temperature < 580{degrees}C), making it favorable for commercial solar cell fabrication.

  13. Solar and magnetic declination control on the electrojet and distributed currents in the ionosphere over Jicamarca

    SciTech Connect

    Muralikrishna, P.; Abdu, M.A.

    1988-02-01

    Daytime variation in the average east-west drift velocity of electrons in the height range of 95--110 km over Jicamarca (0.9 /sup 0/N, dip latitude) is compared with variation in the horizontal component of the geomagnetic field at the closeby Huancayo station (0.6 /sup 0/N, dip latitude). On magnetically quiet days, the ratio of ..delta..H to the electron drift velocity shows a local time variation asymmetric with respect to local noon, although one would expect a symmetric cos chi (where chi is the solar zenith angle) type of variation for the same, if, indeed, ..delta..H arises solely from the electrojet region in which the electron drift velocities are measured. The observed asymmetry indicates significant contribution of distributed currents from height regions above the electrojet in the integrated current represented by ..delta..H. Further, the observed seasonal variation in the degree of the asymmetry seems to point out the importance of magnetic and solar declination angles in controlling the relative contributions of the distributed (and electrojet) currents to the magnitude of the observed ..delta..H values. copyright American Geophysical Union 1988

  14. Controlling the conduction band offset for highly efficient ZnO nanorods based perovskite solar cell

    SciTech Connect

    Dong, Juan; Shi, Jiangjian; Li, Dongmei; Luo, Yanhong; Meng, Qingbo

    2015-08-17

    The mechanism of charge recombination at the interface of n-type electron transport layer (n-ETL) and perovskite absorber on the carrier properties in the perovskite solar cell is theoretically studied. By solving the one dimensional diffusion equation with different boundary conditions, it reveals that the interface charge recombination in the perovskite solar cell can be suppressed by adjusting the conduction band offset (ΔE{sub C}) at ZnO ETL/perovskite absorber interface, thus leading to improvements in cell performance. Furthermore, Mg doped ZnO nanorods ETL has been designed to control the energy band levels. By optimizing the doping amount of Mg, the conduction band minimum of the Mg doped ZnO ETL has been raised up by 0.29 eV and a positive ΔE{sub C} of about 0.1 eV is obtained. The photovoltage of the cell is thus significantly increased due to the relatively low charge recombination.

  15. Study on the application of NASA energy management techniques for control of a terrestrial solar water heating system

    NASA Technical Reports Server (NTRS)

    Swanson, T. D.; Ollendorf, S.

    1979-01-01

    This paper addresses the potential for enhanced solar system performance through sophisticated control of the collector loop flow rate. Computer simulations utilizing the TRNSYS solar energy program were performed to study the relative effect on system performance of eight specific control algorithms. Six of these control algorithms are of the proportional type: two are concave exponentials, two are simple linear functions, and two are convex exponentials. These six functions are typical of what might be expected from future, more advanced, controllers. The other two algorithms are of the on/off type and are thus typical of existing control devices. Results of extensive computer simulations utilizing actual weather data indicate that proportional control does not significantly improve system performance. However, it is shown that thermal stratification in the liquid storage tank may significantly improve performance.

  16. Performance experiments with alternative advanced teleoperator control modes for a simulated solar maximum satellite repair

    NASA Technical Reports Server (NTRS)

    Das, H.; Zak, H.; Kim, W. S.; Bejczy, A. K.; Schenker, P. S.

    1992-01-01

    Experiments are described which were conducted at the JPL Advanced Teleoperator Lab to demonstrate and evaluate the effectiveness of various teleoperator control modes in the performance of a simulated Solar Max Satellite Repair (SMSR) task. THe SMSR was selected as a test because it is very rich in performance capability requirements and it actually has been performed by two EVA astronauts in the Space Shuttle Bay in 1984. The main subtasks are: thermal blanket removal; installation of a hinge attachment for electrical panel opening; opening of electrical panel; removal of electrical connectors; relining of cable bundles; replacement of electrical panel; securing parts and cables; re-mate electrical connectors; closing of electrical panel; and reinstating thermal blanket. The current performance experiments are limited to thermal blanket cutting, electrical panel unbolting and handling electrical bundles and connectors. In one formal experiment even different control modes were applied to the unbolting and reinsertion of electrical panel screws subtasks. The seven control modes are alternative combinations of manual position and rate control with force feedback and remote compliance referenced to force-torque sensor information. Force-torque sensor and end effector position data and task completion times were recorded for analysis and quantification of operator performance.

  17. GPS-Like Phasing Control of the Space Solar Power System Transmission Array

    NASA Technical Reports Server (NTRS)

    Psiaki, Mark L.

    2003-01-01

    The problem of phasing of the Space Solar Power System's transmission array has been addressed by developing a GPS-like radio navigation system. The goal of this system is to provide power transmission phasing control for each node of the array that causes the power signals to add constructively at the ground reception station. The phasing control system operates in a distributed manner, which makes it practical to implement. A leader node and two radio navigation beacons are used to control the power transmission phasing of multiple follower nodes. The necessary one-way communications to the follower nodes are implemented using the RF beacon signals. The phasing control system uses differential carrier phase relative navigation/timing techniques. A special feature of the system is an integer ambiguity resolution procedure that periodically resolves carrier phase cycle count ambiguities via encoding of pseudo-random number codes on the power transmission signals. The system is capable of achieving phasing accuracies on the order of 3 mm down to 0.4 mm depending on whether the radio navigation beacons operate in the L or C bands.

  18. Solar Anomalous and Magnetospheric Particle Explorer attitude control electronics box design and performance

    NASA Technical Reports Server (NTRS)

    Chamberlin, K.; Clagett, C.; Correll, T.; Gruner, T.; Quinn, T.; Shiflett, L.; Schnurr, R.; Wennersten, M.; Frederick, M.; Fox, S. M.

    1993-01-01

    The attitude Control Electronics (ACE) Box is the center of the Attitude Control Subsystem (ACS) for the Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) satellite. This unit is the single point interface for all of the Attitude Control Subsystem (ACS) related sensors and actuators. Commands and telemetry between the SAMPEX flight computer and the ACE Box are routed via a MIL-STD-1773 bus interface, through the use of an 80C85 processor. The ACE Box consists of the flowing electronic elements: power supply, momentum wheel driver, electromagnet driver, coarse sun sensor interface, digital sun sensor interface, magnetometer interface, and satellite computer interface. In addition, the ACE Box also contains an independent Safehold electronics package capable of keeping the satellite pitch axis pointing towards the sun. The ACE Box has dimensions of 24 x 31 x 8 cm, a mass of 4.3 kg, and an average power consumption of 10.5 W. This set of electronics was completely designed, developed, integrated, and tested by personnel at NASA GSFC. SAMPEX was launched on July 3, 1992, and the initial attitude acquisition was successfully accomplished via the analog Safehold electronics in the ACE Box. This acquisition scenario removed the excess body rates via magnetic control and precessed the satellite pitch axis to within 10 deg of the sun line. The performance of the SAMPEX ACS in general and the ACE Box in particular has been quite satisfactory.

  19. A Practical Application of Microcomputers to Control an Active Solar System.

    ERIC Educational Resources Information Center

    Goldman, David S.; Warren, William

    1984-01-01

    Describes the design and implementation of a microcomputer-based model active solar heating system. Includes discussions of: (1) the active solar components (solar collector, heat exchanger, pump, and fan necessary to provide forced air heating); (2) software components; and (3) hardware components (in the form of sensors and actuators). (JN)

  20. Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture

    NASA Astrophysics Data System (ADS)

    Klein, M.; Pankiewicz, R.; Zalas, M.; Stampor, W.

    2016-07-01

    The charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and spin coherence time of electron-hole (e-h) pairs which are experimentally modified by the photoanode morphology (TiO2 nanoparticles or nanotubes) and the electronic orbital structure of various dye molecules (ruthenium N719, dinuclear ruthenium B1 and fully organic squaraine SQ2 dyes). The observed MFE is attributed to magnetic-field-induced spin-mixing of (e-h) pairs according to the Δg mechanism.

  1. Design of self-calibrating controllers for heliostats in a solar power plant

    NASA Astrophysics Data System (ADS)

    Baheti, R. S.; Scott, P. F.

    1980-12-01

    A self-calibrating controller is developed for reducing installation and drive errors in a heliostat (steerable mirror used in solar/electric energy conversion). In this scheme, the heliostat periodically tracks the sun, which serves as a precision position reference. The difference between commanded and actual drive angles is used to estimate the coefficients of a model representing installation and drive errors. The calibrated model is then used to correct the drive actuator commands for these error sources when the heliostat is in a tracking mode (its principle mode of operation). Simulation results are given for a typical heliostat configuration with realistic errors. The algorithm is very effective in reducing beam steering errors. The concept is demonstrated using a prototype test apparatus and is shown to achieve an error reduction of more than 5:1.

  2. Energy Efficient Glazing for Adaptive Solar Control Fabricated with Photothermotropic Hydrogels Containing Graphene Oxide

    PubMed Central

    Kim, Dowan; Lee, Eunsu; Lee, Heon Sang; Yoon, Jinhwan

    2015-01-01

    Glazing for adaptive solar control is the most promising for energy efficient development, because the use of this technology in buildings can be expected to significantly impact energy use and efficiency by screening sunlight that enters a building in summer. To achieve autonomous adjustable transparency, we have developed photothermotropic material system by combining photothermal materials with thermotropic hydrogels. We found that graphene oxide dispersed within a hydrogel matrix effectively converts the photo energy of sunlight into thermal energy, providing the efficient means to trigger transparency of thermotropic hydrogels. Therefore, we could develop switchable glazing of novel photothermotropic mechanism that screen strong sunlight and heat radiation in response to the sunlight intensity, as well as the temperature. Furthermore, in this study, a prototype device was manufactured with developed materials and successfully operated in outdoor testing. PMID:25561372

  3. Energy efficient glazing for adaptive solar control fabricated with photothermotropic hydrogels containing graphene oxide.

    PubMed

    Kim, Dowan; Lee, Eunsu; Lee, Heon Sang; Yoon, Jinhwan

    2015-01-06

    Glazing for adaptive solar control is the most promising for energy efficient development, because the use of this technology in buildings can be expected to significantly impact energy use and efficiency by screening sunlight that enters a building in summer. To achieve autonomous adjustable transparency, we have developed photothermotropic material system by combining photothermal materials with thermotropic hydrogels. We found that graphene oxide dispersed within a hydrogel matrix effectively converts the photo energy of sunlight into thermal energy, providing the efficient means to trigger transparency of thermotropic hydrogels. Therefore, we could develop switchable glazing of novel photothermotropic mechanism that screen strong sunlight and heat radiation in response to the sunlight intensity, as well as the temperature. Furthermore, in this study, a prototype device was manufactured with developed materials and successfully operated in outdoor testing.

  4. SOLERAS - Solar Controlled Environment Agriculture Project. Final report, Volume 5. Science Applications, Incorporated system requirements definition

    SciTech Connect

    Not Available

    1985-01-01

    This report sets forth the system requirements for a Solar Controlled-Environment Agriculture System (SCEAS) Project. In the report a conceptual baseline system description for an engineering test facility is given. This baseline system employs a fluid roof/roof filter in combination with a large storage tank and a ground water heat exchanger in order to provide cooling and heating as needed. Desalination is accomplished by pretreatment followed by reverse osmosis. Energy is provided by means of photovoltaics and wind machines in conjunction with storage batteries. Site and climatic data needed in the design process are given. System performance specifications and integrated system design criteria are set forth. Detailed subsystem design criteria are presented and appropriate references documented.

  5. Magnetic field effects in dye-sensitized solar cells controlled by different cell architecture

    PubMed Central

    Klein, M.; Pankiewicz, R.; Zalas, M.; Stampor, W.

    2016-01-01

    The charge recombination and exciton dissociation are generally recognized as the basic electronic processes limiting the efficiency of photovoltaic devices. In this work, we propose a detailed mechanism of photocurrent generation in dye-sensitized solar cells (DSSCs) examined by magnetic field effect (MFE) technique. Here we demonstrate that the magnitude of the MFE on photocurrent in DSSCs can be controlled by the radius and spin coherence time of electron-hole (e-h) pairs which are experimentally modified by the photoanode morphology (TiO2 nanoparticles or nanotubes) and the electronic orbital structure of various dye molecules (ruthenium N719, dinuclear ruthenium B1 and fully organic squaraine SQ2 dyes). The observed MFE is attributed to magnetic-field-induced spin-mixing of (e-h) pairs according to the Δg mechanism. PMID:27440452

  6. The research of the solar panels-commutator-inverter-load system with the pulse-amplitude control

    NASA Astrophysics Data System (ADS)

    Taissariyeva, K. N.; Issembergenov, N. T.

    2014-11-01

    The system "solar panels-commutator-inverter-load" with amplitude-impulse control was researched. It was shown that if the solar panels are located in a certain way at the input of the inverter, it will be possible to get multilevel voltage close to sine wave with the help of amplitude-impulse control of commutator at the output of inverter. Herewith the effect is saving of solar panels depending on the quantity of voltage level, and also the enhanced voltage distortion coefficient (THD). For instance, with 8-level of voltage 28,2% and THD=4,64%, with 13-level of voltage, 30,5% and THD=2,65%, and with 26-level of voltage 31,7% and THD=1,22%. The given results were obtained through computer modeling and experimental research.

  7. Daytime Solar Heating Controls Downy Mildew Peronospora belbahrii in Sweet Basil.

    PubMed

    Cohen, Yigal; Rubin, Avia E

    2015-01-01

    The biotrophic oomycete Peronospora belbahrii causes a devastating downy mildew disease in sweet basil. Due to the lack of resistant cultivars current control measures rely heavily on fungicides. However, resistance to fungicides and strict regulation on their deployment greatly restrict their use. Here we report on a 'green' method to control this disease. Growth chamber studies showed that P. belbahrii could hardly withstand exposure to high temperatures; exposure of spores, infected leaves, or infected plants to 35-45 °C for 6-9 hours suppressed its survival. Therefore, daytime solar heating was employed in the field to control the downy mildew disease it causes in basil. Covering growth houses of sweet basil already infected with downy mildew with transparent infra-red-impermeable, transparent polyethylene sheets raised the daily maximal temperature during sunny hours by 11-22 °C reaching 40-58 °C (greenhouse effect). Such coverage, applied for a few hours during 1-3 consecutive days, had a detrimental effect on the survival of P. belbahrii: killing the pathogen and/or suppressing disease progress while enhancing growth of the host basil plants.

  8. Solar Output Controls Periodicity in Lake Productivity and Wetness at Southernmost South America

    PubMed Central

    Pérez-Rodríguez, Marta; Gilfedder, Benjamin-Silas; Hermanns, Yvonne-Marie; Biester, Harald

    2016-01-01

    Cyclic changes in total solar irradiance (TSI) during the Holocene are known to affect global climatic conditions and cause cyclic climatic oscillations, e.g., Bond events and related changes of environmental conditions. However, the processes how changes in TSI affect climate and environment of the Southern Hemisphere, especially in southernmost South America, a key area for the global climate, are still poorly resolved. Here we show that highly sensitive proxies for aquatic productivity derived from sediments of a lake near the Chilean South Atlantic coast (53 °S) strongly match the cyclic changes in TSI throughout the Holocene. Intra-lake productivity variations show a periodicity of ~200–240 years coherent with the time series of TSI-controlled cosmogenic nuclide 10Be production. In addition TSI dependent periodicity of Bond events (~1500 years) appear to control wetness at the LH site indicated by mineral matter erosion from the catchment to the lake assumingly through shifts of the position of the southern westerly wind belt. Thus, both intra-lake productivity and wetness at the southernmost South America are directly or indirectly controlled by TSI. PMID:27869191

  9. Daytime Solar Heating Controls Downy Mildew Peronospora belbahrii in Sweet Basil

    PubMed Central

    Cohen, Yigal; Rubin, Avia E.

    2015-01-01

    The biotrophic oomycete Peronospora belbahrii causes a devastating downy mildew disease in sweet basil. Due to the lack of resistant cultivars current control measures rely heavily on fungicides. However, resistance to fungicides and strict regulation on their deployment greatly restrict their use. Here we report on a ‘green’ method to control this disease. Growth chamber studies showed that P. belbahrii could hardly withstand exposure to high temperatures; exposure of spores, infected leaves, or infected plants to 35-45°C for 6-9 hours suppressed its survival. Therefore, daytime solar heating was employed in the field to control the downy mildew disease it causes in basil. Covering growth houses of sweet basil already infected with downy mildew with transparent infra-red-impermeable, transparent polyethylene sheets raised the daily maximal temperature during sunny hours by 11-22°C reaching 40-58°C (greenhouse effect). Such coverage, applied for a few hours during 1-3 consecutive days, had a detrimental effect on the survival of P. belbahrii: killing the pathogen and/or suppressing disease progress while enhancing growth of the host basil plants. PMID:25992649

  10. Control and Study of the Stoichiometry in Evaporated Perovskite Solar Cells.

    PubMed

    Teuscher, Joël; Ulianov, Alexey; Müntener, Othmar; Grätzel, Michael; Tétreault, Nicolas

    2015-11-01

    Herein, we present the precise stoichiometric control of methlyammonium lead iodide perovskite thin-films using high vacuum dual-source vapor-phase deposition. We found that UV/Vis absorption and emission spectra were inadequate for assessing precisely the perovskite composition. Alternatively, inductively coupled plasma mass spectrometry (ICP-MS) is used to give precise, reproducible, quantitative measurements of the I/Pb ratio without systematic errors that often result from varying device thicknesses and morphologies. This controlled deposition method enables better understanding of the evaporation and deposition processes; methylammonium iodide evaporation appears omnidirectional, controlled using the chamber pressure and incorporated in the film through interaction with the unidirectionally evaporated PbI2. Furthermore, these thin-films were incorporated into solar cell device architectures with the best photovoltaic performance and reproducibility obtained for devices made with stoichiometric perovskite active layers. Additionally, and particularly pertinent to the field of perovskite photovoltaics, we found that the I-V hysteresis was unaffected by varying the film stoichiometry.

  11. Solar Output Controls Periodicity in Lake Productivity and Wetness at Southernmost South America

    NASA Astrophysics Data System (ADS)

    Pérez-Rodríguez, Marta; Gilfedder, Benjamin-Silas; Hermanns, Yvonne-Marie; Biester, Harald

    2016-11-01

    Cyclic changes in total solar irradiance (TSI) during the Holocene are known to affect global climatic conditions and cause cyclic climatic oscillations, e.g., Bond events and related changes of environmental conditions. However, the processes how changes in TSI affect climate and environment of the Southern Hemisphere, especially in southernmost South America, a key area for the global climate, are still poorly resolved. Here we show that highly sensitive proxies for aquatic productivity derived from sediments of a lake near the Chilean South Atlantic coast (53 °S) strongly match the cyclic changes in TSI throughout the Holocene. Intra-lake productivity variations show a periodicity of ~200–240 years coherent with the time series of TSI-controlled cosmogenic nuclide 10Be production. In addition TSI dependent periodicity of Bond events (~1500 years) appear to control wetness at the LH site indicated by mineral matter erosion from the catchment to the lake assumingly through shifts of the position of the southern westerly wind belt. Thus, both intra-lake productivity and wetness at the southernmost South America are directly or indirectly controlled by TSI.

  12. Solar Output Controls Periodicity in Lake Productivity and Wetness at Southernmost South America.

    PubMed

    Pérez-Rodríguez, Marta; Gilfedder, Benjamin-Silas; Hermanns, Yvonne-Marie; Biester, Harald

    2016-11-21

    Cyclic changes in total solar irradiance (TSI) during the Holocene are known to affect global climatic conditions and cause cyclic climatic oscillations, e.g., Bond events and related changes of environmental conditions. However, the processes how changes in TSI affect climate and environment of the Southern Hemisphere, especially in southernmost South America, a key area for the global climate, are still poorly resolved. Here we show that highly sensitive proxies for aquatic productivity derived from sediments of a lake near the Chilean South Atlantic coast (53 °S) strongly match the cyclic changes in TSI throughout the Holocene. Intra-lake productivity variations show a periodicity of ~200-240 years coherent with the time series of TSI-controlled cosmogenic nuclide (10)Be production. In addition TSI dependent periodicity of Bond events (~1500 years) appear to control wetness at the LH site indicated by mineral matter erosion from the catchment to the lake assumingly through shifts of the position of the southern westerly wind belt. Thus, both intra-lake productivity and wetness at the southernmost South America are directly or indirectly controlled by TSI.

  13. Morphology control of polymer: Fullerene solar cells by nanoparticle self-assembly

    NASA Astrophysics Data System (ADS)

    Zhang, Wenluan

    During the past two decades, research in the field of polymer based solar cells has attracted great effort due to their simple processing, mechanical flexibility and potential low cost. A standard polymer solar cell is based on the concept of a bulk-heterojunction composed of a conducting polymer as the electron donor and a fullerene derivative as the electron acceptor. Since the exciton lifetime is limited, this places extra emphasis on control of the morphology to obtain improved device performance. In this thesis, detailed characterization and novel morphological design of polymer solar cells was studied, in addition, preliminary efforts to transfer laboratory scale methods to industrialized device fabrication was made. Magnetic contrast neutron reflectivity was used to study the vertical concentration distribution of fullerene nanoparticles within poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2- b]thiophene (pBTTT) thin film. Due to the wide space between the side chains of polymer, these fullerene nanoparticles intercalate between them creating a stable co-crystal structure. Therefore, a high volume fraction of fullerene was needed to obtain optimal device performance as phase separated conductive pathways are required and resulted in a homogeneous fullerene concentration profile through the film. Small angle neutron scattering was used to find there is amorphous fullerene even at lower concentration since it was previously believed that all fullerene formed a co-crystal. These fullerene molecules evolve into approximately 15 nm sized agglomerates at higher concentrations to improve electron transport. Unfortunately, thermal annealing gives these agglomerates mobility to form micrometer sized crystals and reduce the device performance. In standard poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCMBM) solar cells, a higher concentration of PCBM at the cathode interface is desired due to the band alignment structure. This was

  14. Lead Iodide Thin Film Crystallization Control for High-Performance and Stable Solution-Processed Perovskite Solar Cells.

    PubMed

    Yang, Lijun; Wang, Jingchuan; Leung, Wallace Woon-Fong

    2015-07-15

    PbI2 thin film crystallization control is a prerequisite of high-quality perovskite thin film for sequentially solution-processed perovskite solar cells. An efficient and simple method has been developed by adding HCl to improve perovskite thin film quality, and an efficiency of 15.2% is obtained. This approach improves coverage, uniformity, and stability of pervoskite thin film.

  15. Analytical and experimental studies of an all specular thermal control louver system in a solar vacuum environment.

    NASA Technical Reports Server (NTRS)

    Michalek, T. J.; Stipandic, E. A.; Coyle, M. J.

    1972-01-01

    Thermal control louvers are used on the ATS-F&G spacecraft to regulate temperature by varying the effective radiating area. Since solar energy on louvers has a detrimental effect on their ability to radiate energy, an analytical and experimental program was developed to evaluate the performance of an all specular louver system as a function of sun angle and blade angle. Solar simulation tests and analyses show a maximum effective absorptance of .25 for the full open condition. The application of white paint to the blades resulted in lowering the blade temperatures by 130 C without significantly affecting the system performance.

  16. Input Voltage Loop Control with AC Current Feedback for Buck Boost Regulators (B2R) Used as Solar Array Regulators

    NASA Astrophysics Data System (ADS)

    Mourra, Olivier; Fernandez, Arturo; Tonicello, Ferdinando

    2014-08-01

    In a satellite, the main function of a Power Conditioning Unit is to manage the energy coming from several power sources (usually solar arrays and battery) and to deliver it continuously to the users in an appropriate form during the overall mission. Solar Array Regulators are used to extract the power from the SA in order to recharge the battery and to supply the loads during sunlight. The objective of this paper is to present a control technique that can be used when segregated buck, boost or buck boost SAR are implemented. The paper demonstrate theoretically and experimentally the feasibility of this technique.

  17. Efficiency enhancement in solid state dye sensitized solar cells by including inverse opals with controlled layer thicknesses

    NASA Astrophysics Data System (ADS)

    Zheng, Hanbin; Shah, Said Karim; Abbas, Mamatimin; Ly, Isabelle; Rivera, Thomas; Almeida, Rui M.; Hirsch, Lionel; Toupance, Thierry; Ravaine, Serge

    2016-09-01

    The photoconversion efficiency of dye sensitized solar cells can be enhanced by the incorporation of light management nanostructures such as photonic crystals. Here, we present a facile route to incorporate titania inverse opals into solid state dye sensitized solar cells and report photoconversion efficiency enhancements of up to 56% compared with a model system without the inverse opal. Our approach is based on the precise design of titania inverse opals with a predetermined thickness that can be controlled at the individual layer level. By choosing an inverse opal exhibiting a photonic bandgap which overlaps the absorption bands of the dye, our results show that there is an optimal thickness of the inverse opal structure for maximum efficiency enhancement of the cell. This is the first experimental proof that the thickness of a titania inverse opal plays a pivotal role in cell efficiency enhancement in solid state dye sensitized solar cells.

  18. Static and Dynamic Characteristic Models of Global Solar Radiation Fluctuation in the Scope of Load Frequency Control

    NASA Astrophysics Data System (ADS)

    Akatsuka, Motoki; Hara, Ryoichi; Kita, Hiroyuki; Takitani, Katsuyuki; Saito, Masami

    Penetration of photovoltaic generation (PV) system into the power system may give some negative impacts to stable operations of power system; for example, to the frequency control. Therefore, investigation on the short-term fluctuation of PV generation is important as a precaution against further PV penetration. Since the PV generation is almost proportional to the incident solar radiation, this paper develops static and dynamic characteristic models for short-term fluctuation in the global solar radiation. The static characteristic model is a set of standard deviations which have been statistically estimated based on the past observed data. The dynamic characteristic model is autoregressive models which are designed for the actually observed time sequential short-term fluctuation data. In both models, the clearness index is used to eliminate seasonal variation of solar radiation.

  19. Stray light control for asteroid detection at low solar elongation for the NEOSSat micro-satellite telescope

    NASA Astrophysics Data System (ADS)

    Isbrucker, Victor; Stauder, John; Laurin, Denis; Hollinger, Allan

    2012-09-01

    The Near Earth Object Surveillance Satellite (NEOSSat) is a small satellite dedicated to finding near Earth asteroids. Its surveying strategy consists of imaging areas of the sky to low solar elongation, while in a sun synchronous polar orbit (dawn-dusk). A high performance baffle will control stray light mainly due to Earth shine. Observation scenarios require solar shielding down to 45 degree solar elongation over a wide range of ecliptic latitudes. In order to detect the faintest objects (approx 20th v mag) given a 15 cm telescope and CCD detection system, background from stray light is a critical operational concern. The required attenuation is in the order of 10-12. The requirement was verified by analyses; testing was not attempted because the level of attenuation is difficult to measure reliably. We report consistent results of stray light optical modelling from two independent analyses. Launch is expected for late 2012.

  20. Thermal system design and modeling of meniscus controlled silicon growth process for solar applications

    NASA Astrophysics Data System (ADS)

    Wang, Chenlei

    The direct conversion of solar radiation to electricity by photovoltaics has a number of significant advantages as an electricity generator. That is, solar photovoltaic conversion systems tap an inexhaustible resource which is free of charge and available anywhere in the world. Roofing tile photovoltaic generation, for example, saves excess thermal heat and preserves the local heat balance. This means that a considerable reduction of thermal pollution in densely populated city areas can be attained. A semiconductor can only convert photons with the energy of the band gap with good efficiency. It is known that silicon is not at the maximum efficiency but relatively close to it. There are several main parts for the photovoltaic materials, which include, single- and poly-crystalline silicon, ribbon silicon, crystalline thin-film silicon, amorphous silicon, copper indium diselenide and related compounds, cadmium telluride, et al. In this dissertation, we focus on melt growth of the single- and poly-crystalline silicon manufactured by Czochralski (Cz) crystal growth process, and ribbon silicon produced by the edge-defined film-fed growth (EFG) process. These two methods are the most commonly used techniques for growing photovoltaic semiconductors. For each crystal growth process, we introduce the growth mechanism, growth system design, general application, and progress in the numerical simulation. Simulation results are shown for both Czochralski and EFG systems including temperature distribution of the growth system, velocity field inside the silicon melt and electromagnetic field for the EFG growth system. Magnetic field is applied on Cz system to reduce the melt convection inside crucible and this has been simulated in our numerical model. Parametric studies are performed through numerical and analytical models to investigate the relationship between heater power levels and solidification interface movement and shape. An inverse problem control scheme is developed to

  1. Position-controlled III-V compound semiconductor nanowire solar cells by selective-area metal-organic vapor phase epitaxy.

    PubMed

    Fukui, Takashi; Yoshimura, Masatoshi; Nakai, Eiji; Tomioka, Katsuhiro

    2012-01-01

    We demonstrate position-controlled III-V semiconductor nanowires (NWs) by using selective-area metal-organic vapor phase epitaxy and their application to solar cells. Efficiency of 4.23% is achieved for InP core-shell NW solar cells. We form a 'flexible NW array' without a substrate, which has the advantage of saving natural resources over conventional thin film photovoltaic devices. Four junction NW solar cells with over 50% efficiency are proposed and discussed.

  2. Three-dimensional core-shell hybrid solar cells via controlled in situ materials engineering.

    PubMed

    Mariani, Giacomo; Wang, Yue; Wong, Ping-Show; Lech, Andrew; Hung, Chung-Hong; Shapiro, Joshua; Prikhodko, Sergey; El-Kady, Maher; Kaner, Richard B; Huffaker, Diana L

    2012-07-11

    Three-dimensional core-shell organic-inorganic hybrid solar cells with tunable properties are demonstrated via electropolymerization. Air-stable poly(3,4-ethylenedioxythiophene) (PEDOT) shells with controlled thicknesses are rapidly coated onto periodic GaAs nanopillar arrays conformally, preserving the vertical 3D structure. The properties of the organic layer can be readily tuned in situ, allowing for (1) the lowering of the highest occupied molecular orbital level (|ΔE| ∼ 0.28 eV), leading to the increase of open-circuit voltage (V(OC)), and (2) an improvement in PEDOT conductivity that results in enhanced short-circuit current densities (J(SC)). The incorporation of various anionic dopants in the polymer during the coating process also enables the tailoring of the polymer/semiconductor interface transport properties. Systematic tuning of the device properties results in a J(SC) of 13.6 mA cm(-2), V(OC) of 0.63 V, peak external quantum efficiency of 58.5%, leading to a power conversion efficiencies of 4.11%.

  3. A feasibility study for controlling self-organized production of plasmonic enhancement interfaces for solar cells

    NASA Astrophysics Data System (ADS)

    Zolfaghari Borra, Mona; Kayra Güllü, Seda; Es, Fırat; Demircioğlu, Olgu; Günöven, Mete; Turan, Raşit; Bek, Alpan

    2014-11-01

    The decoration of metal nanoparticles (MNPs) by the self-organized mechanism of dewetting is utilized as a suitable method for plasmonic interface integration to large area full-scale solar cell (SC) devices. Reflection measurements are performed on both flat and textured silicon (Si) SCs in order to investigate the local plasmonic resonances of the MNPs. The effects of particle size and thickness of silicon nitride (Si3N4) anti-reflection coating layer are investigated by reflection measurements and the shift of plasmon resonance peak position. It is found that surface roughness, annealing time, annealing temperature, and varying Si3N4 thickness can be used as mechanisms to control the size distribution, shape of the resultant nano-islands, and SC efficiency. The findings on the most suitable nanoparticle system production parameters by this method, depends on the applied substrate properties which are expected to guide further applications of plasmonic interfaces and also to the other kinds of device structures in the ultimate quest for attaining affordable high efficiency SCs.

  4. Selective Morphology Control of Bulk Heterojunction in Polymer Solar Cells Using Binary Processing Additives.

    PubMed

    Jung, Yen-Sook; Yeo, Jun-Seok; Kim, Nam-Koo; Lee, Sehyun; Kim, Dong-Yu

    2016-11-09

    We report the effect of binary additives on the fabrication of polymer solar cells (PSCs) based on a bulk heterojunction (BHJ) system. The combination of 1,8-diiodooctane (DIO), a high-boiling and selective solvent, for fullerene derivatives and poly(dimethylsiloxane) (PDMS) precursor, a nonvolatile insulating additive, affords complementary functions on the effective modulation of BHJ morphology. It was found that DIO and PDMS precursor each play different roles in the control of BHJ morphology, and thus, the power conversion efficiency (PCE) can be further enhanced to 7.6% by improving the fill factor (FF) from 6.8% compared to that achieved using a conventional device employing only a DIO additive. In the BHJ of the active layer, DIO suppressed the large phase separation of PBDTTT-CF and PC71BM while allowing the formation of continuous polymer networks in the donor polymer through phase separation of the PDMS precursor and BHJ components. The appropriate amount of PDMS precursor does not disturb charge transport in the BHJ despite having insulating properties. In addition, the dependence of photovoltaic parameters on different light intensities reveals that the charge recombination in the device with DIO and PDMS precursor decreases compared to that achieved using the device with only DIO.

  5. A study of a solar central power plant with a gas turbine - Project Sirocco modelling and control

    NASA Astrophysics Data System (ADS)

    Kacim, M.

    A thermodynamics and receiver design analysis is presented for a solar tower power plant, together with a control model for operations in varying working conditions. The analysis covers the central receiver and the gas-air turbine, adapted for functioning at 820 C, such as was experienced with the 100 kW Project Sirocco test station. A heliostat field concentrates solar energy onto a central receiver traversed by compressed air, which is allowed to expand while driving a turbine generator. A combustion chamber is included in the loop to augment the thermal performance when insufficient solar energy is available. The plant can be either grid-connected or stand alone. Static and dynamic characteristics of the thermal loop are modelled, and are included in the development of control laws based on quadratic criteria. An optimized control scheme is devised which features weighting criteria matrices, and the results of simulations covering different insolation levels are reported. Finally, an adjoint state control system is produced to account for peculiarities of the power plant.

  6. Optimizing process time of laser drilling processes in solar cell manufacturing by coaxial camera control

    NASA Astrophysics Data System (ADS)

    Jetter, Volker; Gutscher, Simon; Blug, Andreas; Knorz, Annerose; Ahrbeck, Christopher; Nekarda, Jan; Carl, Daniel

    2014-03-01

    In emitter wrap through (EWT) solar cells, laser drilling is used to increase the light sensitive area by removing emitter contacts from the front side of the cell. For a cell area of 156 x 156 mm2, about 24000 via-holes with a diameter of 60 μm have to be drilled into silicon wafers with a thickness of 200 μm. The processing time of 10 to 20 s is determined by the number of laser pulses required for safely opening every hole on the bottom side. Therefore, the largest wafer thickness occurring in a production line defines the processing time. However, wafer thickness varies by roughly +/-20 %. To reduce the processing time, a coaxial camera control system was integrated into the laser scanner. It observes the bottom breakthrough from the front side of the wafer by measuring the process emissions of every single laser pulse. To achieve the frame rates and latency times required by the repetition rate of the laser (10 kHz), a camera based on cellular neural networks (CNN) was used where the images are processed directly on the camera chip by 176 x 144 sensor-processor-elements. One image per laser pulse is processed within 36 μs corresponding to a maximum pulse rate of 25 kHz. The laser is stopped when all of the holes are open on the bottom side. The result is a quality control system in which the processing time of a production line is defined by average instead of maximum wafer thickness.

  7. Titanium oxide morphology controls charge collection efficiency in quantum dot solar cells.

    PubMed

    Kolay, Ankita; Kumar, P Naresh; Kumar, Sarode Krishna; Deepa, Melepurath

    2017-02-08

    Charge transfer at the TiO2/quantum dots (QDs) interface, charge collection at the TiO2/QDs/current collector (FTO or SnO2:F) interface, and back electron transfer at the TiO2/QDs/S(2-) interface are processes controlled by the electron transport layer or TiO2. These key processes control the power conversion efficiencies (PCEs) of quantum dot solar cells (QDSCs). Here, four TiO2 morphologies, porous nanoparticles (PNPs), nanowires (NWs), nanosheets (NSHs) and nanoparticles (NPs), were sensitized with CdS and the photovoltaic performances were compared. The marked differences in the cell parameters on going from one morphology to the other have been explained by correlating the shape, structure and the above-described interfacial properties of a given TiO2 morphology to the said parameters. The average magnitudes of PCEs follow the order: NWs (5.96%) > NPs (4.95%) > PNPs (4.85%) > NSHs (2.5%), with the champion cell based on NWs exhibiting a PCE of 6.29%. For NWs, an optimal balance between the fast photo-excited electron injection to NWs at the NW/CdS interface, the high resistance offered at the TiO2 NW/CdS/S(2-) interfaces to electron recombination with the oxidized electrolyte or with the holes in CdS, the low electron transport resistance in NWs, and low dark currents, yields the highest efficiency due to directional unhindered transport of electrons afforded by the NWs. For NSHs, electron trapping in the two dimensional sheets, and a high electron recombination rate prevent the effective transfer of electrons to FTO, thus reducing short circuit current density significantly, resulting in a poor performance. This study provides a deep understanding of charge transfer, transport and collection processes necessary for the design of efficient QDSCs.

  8. Fabrication of large-format holograms in dichromated gelatin films for sun control and solar concentrators

    NASA Astrophysics Data System (ADS)

    Stojanoff, Christo G.; Schuette, Hartmut; Schulat, Jochen; Kubiza, Ralf; Froening, Philipp

    1997-05-01

    Dichromated gelatin layers (DCG) facilitate the design and fabrication of large format holographic optical elements (HOE) of high optical quality and diffraction efficiency. The HOEs are used for the fabrication of spectrally selective solar concentrators and as glazing materials for daylighting and passive sun control in buildings. The suitability of HOEs in these applications depends upon the achievable bandwidth, operating central wavelength, dispersion characteristics and low absorption losses. The HOEs are fabricated on glass or plastic film substrata in a DCG-layer of 5 to 30 micrometer thickness. The layer thickness and the gradient ar precisely controlled during the layer deposition and drying (plus or minus 1 micrometer and 0.1 micrometer/cm for standard layer of 10 micrometer thickness). The production process is based on the fabrication of high quality master holograms that are copied by dry copying procedure. The current manufacturing facilities allow the fabrication of 1 m2 HOEs on glass substratum and a continuous production of HOEs on plastic substratum with a width of 20 cm and length of 50 m. This technology is also used to fabricate holograms for instrumentation optics in metrology and for optical interconnects in multichip modules. The fabricated HOEs exhibit the desired operational characteristics: high diffraction efficiency, small Braggshift, large bandwidth and a central wavelength that may be freely selected over a wide spectral range. In this paper, we present the results from the experimental investigation and theoretical analysis of large number of holograms of the transmissive and reflective types. We discuss the attained angular and wavelength spectra, bandwidths, wavelength shifts and the diffraction efficiencies as functions of the holographic parameters. The HOEs are made for technical applications and are designed to operate in the 300 nm - 1500 m spectral range.

  9. Direct evidence for solar wind control of Jupiter's hectometer-wavelength radio emission

    NASA Technical Reports Server (NTRS)

    Desch, M. D.; Barrow, C. H.

    1984-01-01

    Observations of the solar wind close to Jupiter, by the Voyager 1 and Voyager 2 spacecraft in 1978 and 1979, are compared with the hectometer wavelength radio emission from the planet. A significant positive correlation is found between variations in the solar wind plasma density at Jupiter and the level of Jovian radio emission output. During the 173-day interval studied for the Voyager 2 data, the radio emission displayed a long term periodicity of about 13 days, identical to that shown by the solar wind density at Jupiter and consistent with the magnetic sector structure association already proposed for groundbased observations of the decameter wavelength emission.

  10. Redox Active Compounds in Controlled Radical Polymerization and Dye-Sensitized Solar Cells: Mutual Solutions to Disparate Problems.

    PubMed

    Ballard, Nicholas; Mecerreyes, David; Asua, José M

    2015-12-14

    Controlled radical polymerization (CRP) and dye-sensitized solar cells (DSSCs) are two fields of research that at an initial glance appear to have little in common. However, despite their obvious differences, both in application and in scientific nature, a closer look reveals a striking similarity between many of the compounds widely used as control agents in radical polymerization and as redox couples in dye-sensitized solar cells. Herein, we review the various redox active compounds used and examine the characteristics that give them the ability to perform this dual function. In addition we explore the advances in the understanding of the structural features that enhance their activity in both CRP and DSSCs. It is hoped that such a comparison will be conducive to improving process performance in both fields.

  11. Roof aperture system for selective collection and control of solar energy for building heating, cooling and daylighting

    DOEpatents

    Sanders, William J.; Snyder, Marvin K.; Harter, James W.

    1983-01-01

    The amount of building heating, cooling and daylighting is controlled by at least one pair of solar energy passing panels, with each panel of the pair of panels being exposed to a separate direction of sun incidence. A shutter-shade combination is associated with each pair of panels and the shutter is connected to the shade so that rectilinear movement of the shutter causes pivotal movement of the shade.

  12. A study of the factors which control the efficiency of ion-implanted silicon solar cells

    NASA Technical Reports Server (NTRS)

    Douglas, E. C.; Daiello, R. V.

    1980-01-01

    The objective of this work was to determine experimentally the ion-implantation parameters and furnace annealing conditions required to produce high-efficiency solar cells. A comprehensive experimental study was conducted in which the optimum ion-implantation parameters were found by a systematic variation of the implant parameters followed by detailed studies of solar-cell devices. Two furnace heat-treatment techniques were found which effectively anneal the implanted layers and at the same time preserve or improve the diffusion length in the bulk silicon. Detailed characteristics of both the junction and bulk properties of solar cells fabricated over the spectrum of implant parameters are discussed. Optimized implant parameters and annealing conditions were found which allow for the fabrication of 14-15-percent (AM1) efficient solar cells.

  13. Robust stability of solar-power wireless network control system with stochastic time delays based on H∞-norm

    NASA Astrophysics Data System (ADS)

    Al-Azzawi, Waleed; Al-Akaidi, Marwan

    2015-04-01

    In this paper, the robust stability analysis of solar wireless networked control systems (SWNCSs) with stochastic time delays and packet dropout is investigated. The robust model predictive controller (RMPC) technique for the SWNCS is discussed using the linear matrix inequality (LMI) technique. Based on the SWNCS model, the RMPC (a full state feedback controller) can be constructed by using the Lyapunov functional method. Both sensor-to-controller and controller-to-actuator time delays of the SWNCS are considered as stochastic variables controlled by a Markov chain. A discrete-time Markovian jump linear system (MJLS) with norm bounded time delay is presented to model the SWNCSs. Conditions for H∞-norm is used to evaluate stability and stabilization of the fundamental systems derived via LMIs formulation. Finally, an illustrative numerical example is given to demonstrate the effectiveness of the proposed techniques.

  14. Control device for automatic orientation of a solar panel based on a microcontroller (PIC16f628a)

    NASA Astrophysics Data System (ADS)

    Rezoug, M. R.; Krama, A.

    2016-07-01

    This work proposes a control device for autonomous solar tracker based on one axis, It consists of two main parts; the control part which is based on "the PIC16f628a"; it has the role of controlling, measuring and plotting responses. The second part is a mechanical device, which has the role of making the solar panel follows the day-night change of the sun throughout the year. Both parties are established to improve energy generation of the photovoltaic panels. In this paper, we will explain the main operating principles of our system. Also, we will provide experimental results which demonstrate the good performance and the efficiency of this system. This innovation is different from what has been proposed in previous studies. The important points of this system are maximum output energy and minimum energy consumption of solar tracker, its cost is relatively low with simplicity in implementation. The average power increase produced by using the tracking system for a particular day, is over 30 % compared with the static panel.

  15. Solar Control on Jupiter's Equatorial X-ray Emissions: 26-29 November 2003 XMM-Newton Observation

    NASA Technical Reports Server (NTRS)

    Bhardwaj, Anil; Branduardi-Raymont, Graziella; Elsner, Ronald F.; Gladstone, G. Randall; Ramsay, G.; Rodriquez, P.; Soria, R.; Waite, J. Hunter, Jr.; Cravens, Thomas E.

    2004-01-01

    During November 26-29,2003 XMM-Newton observed X-ray emissions from Jupiter for 69 hours. The 0.7-2.0 keV X-ray disk of Jupiter is observed to be brightest at the subsolar point, and limb darkening is seen in the 0.2-2.0 keV and 0.7-2.0 keV images. We present simultaneous lightcurves of Jovian equatorial X-rays and solar X-rays measured by the GOES, SOHO/SEM, and TIMED/SEE satellites. The solar X-ray flares occurring on the Jupiter-facing side of the Sun are matched by corresponding features in the Jovian X- rays. These results support the hypothesis that X-ray emissions from Jovian low-latitudes are solar X-rays scattered and fluoresced from the planet's upper atmosphere, and confirm that the Sun directly controls the non-auroral X-rays fiom Jupiter's disk. Our study suggest that Jovian equatorial X-rays; during certain Jupiter phase, can be used to predict the occurrence of solar flare on the hemisphere of the Sun that is invisible to space weather satellites.

  16. Controlling Morphology and Molecular Packing of Alkane Substituted Phthalocyanine Blend Bulk Heterojunction Solar Cells.

    PubMed

    Jurow, Matthew J; Hageman, Brian A; Dimasi, Elaine; Nam, Chang-Yong; Pabon, Cesar; Black, Charles T; Drain, Charles Michael

    2013-02-07

    Systematic changes in the exocyclic substiution of core phthalocyanine platform tune the absorption properties to yield commercially viable dyes that function as the primary light absorbers in organic bulk heterojunction solar cells. Blends of these complementary phthalocyanines absorb a broader portion of the solar spectrum compared to a single dye, thereby increasing solar cell performance. We correlate grazing incidence small angle x-ray scattering structural data with solar cell performance to elucidate the role of nanomorphology of active layers composed of blends of phthalocyanines and a fullerene derivative. A highly reproducible device architecture is used to assure accuracy and is relevant to films for solar windows in urban settings. We demonstrate that the number and structure of the exocyclic motifs dictate phase formation, hierarchical organization, and nanostructure, thus can be employed to tailor active layer morphology to enhance exciton dissociation and charge collection efficiencies in the photovoltaic devices. These studies reveal that disordered films make better solar cells, short alkanes increase the optical density of the active layer, and branched alkanes inhibit unproductive homogeneous molecular alignment.

  17. Implantable control, telemetry, and solar energy system in the moving actuator type total artificial heart.

    PubMed

    Ahn, J M; Lee, J H; Choi, S W; Kim, W E; Omn, K S; Park, S K; Kim, W G; Roh, J R; Min, B G

    1998-03-01

    The moving actuator type total artificial heart (TAH) developed in the Seoul National University has numerous design improvements based upon the digital signal processor (DSP). These improvements include the implantability of all electronics, an automatic control algorithm, and extension of the battery run-time in connection with an amorphous silicon solar system (SS). The implantable electronics consist of the motor drive, main processor, intelligent Li ion battery management (LIBM) based upon the DSP, telemetry system, and transcutaneous energy transmission (TET) system. Major changes in the implantable electronics include decreasing the temperature rise by over 21 degrees C on the motor drive, volume reduction (40 x 55 x 33 mm, 7 cell assembly) of the battery pack using a Li ion (3.6 V/cell, 900 mA.h), and improvement of the battery run-time (over 40 min) while providing the cardiac output (CO) of 5 L/min at 100 mm Hg afterload when the external battery for testing is connected with the SS (2.5 W, 192.192, 1 kg) for the external battery recharge or the partial TAH drive. The phase locked loop (PLL) based telemetry system was implemented to improve stability and the error correction DSP algorithm programmed to achieve high accuracy. A field focused light emitting diode (LED) was used to obtain low light scattering along the propagation path, similar to the optical property of the laser and miniature sized, mounted on the pancake type TET coils. The TET operating resonance frequency was self tuned in a range of 360 to 410 kHz to provide enough power even at high afterloads. An automatic cardiac output regulation algorithm was developed based on interventricular pressure analysis and carried out in several animal experiments successfully. All electronics have been evaluated in vitro and in vivo and prepared for implantation of the TAH. Substantial progress has been made in designing a completely implantable TAH at the preclinical stage.

  18. Intra-Hour Dispatch and Automatic Generator Control Demonstration with Solar Forecasting - Final Report

    SciTech Connect

    Coimbra, Carlos F. M.

    2016-02-25

    In this project we address multiple resource integration challenges associated with increasing levels of solar penetration that arise from the variability and uncertainty in solar irradiance. We will model the SMUD service region as its own balancing region, and develop an integrated, real-time operational tool that takes solar-load forecast uncertainties into consideration and commits optimal energy resources and reserves for intra-hour and intra-day decisions. The primary objectives of this effort are to reduce power system operation cost by committing appropriate amount of energy resources and reserves, as well as to provide operators a prediction of the generation fleet’s behavior in real time for realistic PV penetration scenarios. The proposed methodology includes the following steps: clustering analysis on the expected solar variability per region for the SMUD system, Day-ahead (DA) and real-time (RT) load forecasts for the entire service areas, 1-year of intra-hour CPR forecasts for cluster centers, 1-year of smart re-forecasting CPR forecasts in real-time for determination of irreducible errors, and uncertainty quantification for integrated solar-load for both distributed and central stations (selected locations within service region) PV generation.

  19. Impact of Solar Control PVB Glass on Vehicle Interior Temperatures, Air-Conditioning Capacity, Fuel Consumption, and Vehicle Range

    SciTech Connect

    Rugh, J.; Chaney, L.; Venson, T.; Ramroth, L.; Rose, M.

    2013-04-01

    The objective of the study was to assess the impact of Saflex1 S-series Solar Control PVB (polyvinyl butyral) configurations on conventional vehicle fuel economy and electric vehicle (EV) range. The approach included outdoor vehicle thermal soak testing, RadTherm cool-down analysis, and vehicle simulations. Thermal soak tests were conducted at the National Renewable Energy Laboratory's Vehicle Testing and Integration Facility in Golden, Colorado. The test results quantified interior temperature reductions and were used to generate initial conditions for the RadTherm cool-down analysis. The RadTherm model determined the potential reduction in air-conditioning (A/C) capacity, which was used to calculate the A/C load for the vehicle simulations. The vehicle simulation tool identified the potential reduction in fuel consumption or improvement in EV range between a baseline and modified configurations for the city and highway drive cycles. The thermal analysis determined a potential 4.0% reduction in A/C power for the Saflex Solar PVB solar control configuration. The reduction in A/C power improved the vehicle range of EVs and fuel economy of conventional vehicles and plug-in hybrid electric vehicles.

  20. Morphology-controllable ZnO nanostructures: Ethanol-assisted synthesis, growth mechanism and solar cell applications

    NASA Astrophysics Data System (ADS)

    Zhu, Y. F.; Fan, D. H.; Dong, Y. W.; Zhou, G. H.

    2014-10-01

    A very cheap solvent, ethanol, was successfully applied to control ZnO crystal growth for fabricating a series of ZnO composite nanostructures. During the experimental process, a two-step chemical route was adopted. In step-one, ZnO nanowire arrays were grown on fluorine-doped tin oxide coated glass substrate. In step-two, the step-one prepared samples were used as substrates for composite nanostructure deposition. The morphologies of the obtained products were characterized by field emission scanning electron microscopy. The results indicate that the morphologies of the final products can be effectively controlled by changing the water/ethanol ratios in the chemical solution. The obtained ZnO composite nanostructures with various morphologies were successfully employed in dye-sensitized solar cells. The light-to-electricity conversion results show that the composite nanostructures consisting of nanowires and pseudospherical nanostructures enable 80% improvement in solar energy conversion efficiency as compared with the nanowire arrays. These results indicate that the synthesized ZnO composite nanostructures are more suitable for application as photoelectrodes in solar cells.

  1. Surface plasmon resonance induced excellent solar control for VO₂@SiO₂ nanorods-based thermochromic foils.

    PubMed

    Zhou, Yijie; Huang, Aibin; Li, Yamei; Ji, Shidong; Gao, Yanfeng; Jin, Ping

    2013-10-07

    Transition-metal oxide nanocrystals are novel candidates for being used as the hosts of localized surface plasmon resonance because they exhibit fascinating properties arising from the unique characteristics of their outer-d valence electrons. VO₂(M) nanocrystal is well-known due to its reversible metal-insulator transition (MIT) temperature near room temperature (∼68 °C) corresponding to the appearance/disappearance of localized surface plasmon resonance across the MIT. In this study, a microemulsion-based method was introduced to synthesize VO₂(M)@SiO₂ nanoparticles which were applied to prepare VO₂-based thermochromic foils owing to a strong and tunable surface plasmon resonance in the metallic state. The optical transmittance spectra demonstrates that the employment of surface plasmon resonance in VO₂-based thermochromic foils greatly improves their solar regulating efficiency up to 18.54%, and provides an unprecedented insight in optimizing VO₂-based thermochromic windows for solar control.

  2. The properties of polycrystalline silicon solar cells with controlled titanium additions

    NASA Technical Reports Server (NTRS)

    Rohatgi, A.; Hopkins, R. H.; Davis, J. R., Jr.

    1981-01-01

    By coupling the results of electrical measurements, such as spectral response, lighted and dark I-V determinations, and deep-level-transient spectroscopy with optical and laser scan photomicroscopy, the effects of grain boundaries and impurities on silicon solar cells were evaluated. Titanium, which produces two deep levels in silicon, degrades cell performance by reducing bulk lifetime and thus cell short-circuit current. Electrically active grain boundaries induce carrier recombination in the bulk and depletion regions of the solar cell. Experimental data imply a small but measurable segregation of titanium into some grain boundaries of the polycrystalline silicon containing high Ti concentration. However, for the titanium-contaminated polycrystalline material used in this study, solar cell performance is dominated by the electrically active titanium concentration in the grains. Microstructural impacts on the devices are of secondary importance

  3. Prevention of thermal buildup by controlled exterior means and solar energy collectors

    SciTech Connect

    Nevins, R.L.

    1981-09-01

    An illustrative embodiment of the invention discloses a solar energy system for a building. A plurality of interlocked thermally conductive flat solar energy collecting plates form a portion of the building's surface. Each of these plates has a web which is generally perpendicular to the web surface. This web supports a suitable tube which is received in notched rafters. The tube contains working fluid which absorbs thermal energy collected by the plates and transfers it to storage or to air flowing in a duct which is formed in the building or structure between a sheet which is attached to the opposite side of the rafters and the flat solar collecting plates which provide one surface of the building.

  4. Solar sail

    SciTech Connect

    Drexler, K.E.

    1986-09-30

    This patent describes a solar sail propulsion system comprising: solar sail means for intercepting light pressure to produce thrust, the solar sail means being a thin metal film; tension truss means having two ends attached at one end to the solar sail means for transferring the thrust from the solar sail and for preventing gross deformation of the solar sail under light pressure, the solar sail means being a plurality of separate generally two-dimensional pieces joined by springs to the tension truss means; a payload attached to the other end of the tension truss means, the tension truss means comprising a plurality of attachment means for attaching shroud lines to the top of the tension truss means and a plurality of the shroud lines attached to the attachment means at one of their ends and the payload at the other; a plurality of reel means attached to the shroud lines for controllably varying the length of the lines; and a plurality of reflective panel means attached to the sail means for controlling the orientation of the system.

  5. Three-dimensional imaging for precise structural control of Si quantum dot networks for all-Si solar cells

    NASA Astrophysics Data System (ADS)

    Kourkoutis, Lena F.; Hao, Xiaojing; Huang, Shujuan; Puthen-Veettil, Binesh; Conibeer, Gavin; Green, Martin A.; Perez-Wurfl, Ivan

    2013-07-01

    All-Si tandem solar cells based on Si quantum dots (QDs) are a promising approach to future high-performance, thin film solar cells using abundant, stable and non-toxic materials. An important prerequisite to achieve a high conversion efficiency in such cells is the ability to control the geometry of the Si QD network. This includes the ability to control both, the size and arrangement of Si QDs embedded in a higher bandgap matrix. Using plasmon tomography we show the size, shape and density of Si QDs, that form in Si rich oxide (SRO)/SiO2 multilayers upon annealing, can be controlled by varying the SRO stoichiometry. Smaller, more spherical QDs of higher densities are obtained at lower Si concentrations. In richer SRO layers ellipsoidal QDs tend to form. Using electronic structure calculations within the effective mass approximation we show that ellipsoidal QDs give rise to reduced inter-QD coupling in the layer. Efficient carrier transport via mini-bands is in this case more likely across the multilayers provided the SiO2 spacer layer is thin enough to allow coupling in the vertical direction.All-Si tandem solar cells based on Si quantum dots (QDs) are a promising approach to future high-performance, thin film solar cells using abundant, stable and non-toxic materials. An important prerequisite to achieve a high conversion efficiency in such cells is the ability to control the geometry of the Si QD network. This includes the ability to control both, the size and arrangement of Si QDs embedded in a higher bandgap matrix. Using plasmon tomography we show the size, shape and density of Si QDs, that form in Si rich oxide (SRO)/SiO2 multilayers upon annealing, can be controlled by varying the SRO stoichiometry. Smaller, more spherical QDs of higher densities are obtained at lower Si concentrations. In richer SRO layers ellipsoidal QDs tend to form. Using electronic structure calculations within the effective mass approximation we show that ellipsoidal QDs give rise to

  6. Comparison of Proportional and On/Off Solar Collector Loop Control Strategies Using a Dynamic Collector Model

    SciTech Connect

    Schiller, Steven R.; Warren, Mashuri L.; Auslander, David M.

    1980-11-01

    In this paper, common control strategies used to regulate the flow of liquid through flat-plate solar collectors are discussed and evaluated using a dynamic collector model. Performance of all strategies is compared using different set points, flow rates, insolation levels and patterns, and ambient temperature conditions. The unique characteristic of the dynamic collector model is that it includes the effect of collector capacitance. Short term temperature response and the energy-storage capability of collector capacitance are shown to play significant roles in comparing on/off and proportional controllers. Inclusion of these effects has produced considerably more realistic simulations than any generated by steady-state models. Finally, simulations indicate relative advantages and disadvantages of both types of controllers, conditions under which each performs better, and the importance of pump cycling and controller set points on total energy collection.

  7. Synthesis, loading control and applications of 2,4,6-triphenylpyrilium as a solar photocatalyst

    NASA Astrophysics Data System (ADS)

    Vercher Perez, Rosa

    2005-07-01

    The technologies or processes of oxidation outpost that uses like energy the solar radiation for the degradation of polluting agents, suppose a novel alternative with important economic and environmental advantages. A proof of it has been the spectacular development which they have been these applications at world-wide level in the last years old, as well as the interest that the subject in international the scientific community has provoked. 2,4,6-trifenilpirilio by its singularity in this field has been chosen for this thesis the cation. It has been left from a study about the fotocatalitica activity of this cation, from the salt of hidrogenosulfato 2,4,6-trifenilpirilio and of the salt of tetrafluorborato 2,4,6-trifenilpirilio, when they act in homogenous phase on polluting agents, derivatives of dissolved fenolicos compounds in residual coming from the industry. In the first stage of the study I confirm the degradativo power of this cation but nevertheless a series of disadvantages in homogena phase was detected, had to the chemical characteristics of this organic species: hidrolitica opening of the ring and impossibility of reusability. With the purpose of correcting these problems it has been investigated and developed different methods from synthesis, in which this cation is supported in inorganic materials, concretely: silica gel, zeolites and sepiolitas. It has been come to the study, of individual form, the parameters that influence of significant form in the yield of the different processes and also has been verified the fotocatalitica activity of the new synthesized materials. In the developed methods it has been managed to totally control the amount of cation supported in the chosen materials and of this form to be able to know the effectiveness his activity like fotocatalizador in heterogenous phase. It is possible to emphasize, that the proposed procedures of synthesis, are quite simple and fast in his execution. The made studies have been carried

  8. Solar control of winter mesospheric echo occurrence at Poker Flat, Alaska

    NASA Technical Reports Server (NTRS)

    Ecklund, W. L.; Balsley, B. B.

    1983-01-01

    Winter mesospheric echoes are observed between about 55 and 80 km when auroral absorption is present during daylight hours. Relatively steady auroral absorption during sunrise and sunset periods causes a distinct onset and decay signature in mesospheric echo occurrence. The echo onset and disappearance time are shown versus height by the inclined lines for four different dates. The more vertical lines give the visible sunlight height/time curves for both sunrise (SR) and sunset (SS). The data is combined and replotted to give the morning onset height and the afternoon disappearance height as a function of solar zenith angle. Echoes are not observed at the lowest heights in the morning until the solar zenith angle is less than 90 deg. The afternoon echoes at the lowest heights also start to disappear as soon as the solar zenith angle exceeds 90 deg, implying that the solar component which sustains the mesospheric echo is screened by a layer extending up to about 60 km. The morning echo at 73 km onsets near the time of visible sunrise, but in the afternoon the 73 km echo lasts well past visible sunset.

  9. Interplanetary Magnetic Field Control of the Entry of Solar Energetic Particles into the Magnetosphere

    NASA Technical Reports Server (NTRS)

    Richard, R. L.; El-Alaoui, M.; Ashour-Abdalla, M.; Walker, R. J.

    2002-01-01

    We have investigated the entry of energetic ions of solar origin into the magnetosphere as a function of the interplanetary magnetic field orientation. We have modeled this entry by following high energy particles (protons and 3 He ions) ranging from 0.1 to 50 MeV in electric and magnetic fields from a global magnetohydrodynamic (MHD) model of the magnetosphere and its interaction with the solar wind. For the most part these particles entered the magnetosphere on or near open field lines except for some above 10 MeV that could enter directly by crossing field lines due to their large gyroradii. The MHD simulation was driven by a series of idealized solar wind and interplanetary magnetic field (IMF) conditions. It was found that the flux of particles in the magnetosphere and transport into the inner magnetosphere varied widely according to the IMF orientation for a constant upstream particle source, with the most efficient entry occurring under southward IMF conditions. The flux inside the magnetosphere could approach that in the solar wind implying that SEPs can contribute significantly to the magnetospheric energetic particle population during typical SEP events depending on the state of the magnetosphere.

  10. Voltage-controlling mechanisms in low-resistivity silicon solar cells - A unified approach

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Swartz, C. K.; Hart, R. E.; Godlewski, M. P.

    1986-01-01

    An experimental technique is used to determine the relative values of the base and emitter components of the dark saturation current of six types of high-voltage low-resistivity silicon solar cells. One of the surprising findings is the suggestion that the magnitude of the minority-carrier mobility may be process-dependent.

  11. Is the O2(a1Δg) Venus nightglow emission controlled by solar activity?

    NASA Astrophysics Data System (ADS)

    Soret, Lauriane; Gérard, Jean-Claude

    2015-12-01

    Several past studies showed that the O2(a1Δg) Venus nightglow emission at 1.27 μm is highly variable on a timescale of hours. We examine whether the intensity of this emission shows a more global trend linked to solar activity.

  12. Enhanced performance of PbS-sensitized solar cells via controlled successive ionic-layer adsorption and reaction.

    PubMed

    Abbas, Muhammad A; Basit, Muhammad A; Park, Tae Joo; Bang, Jin Ho

    2015-04-21

    Despite the potential of PbS quantum dots (QDs) as sensitizers for quantum-dot-sensitized solar cells (QDSSCs), achieving a high photocurrent density over 30 mA cm(-2) remains a challenging task in PbS-sensitized solar cells. In contrast to previous attempts, where Hg(2+)-doping or multi-step post-treatment is necessary, we are capable of achieving a high photocurrent exceeding 30 mA cm(-2) simply by manipulating the successive ionic layer adsorption and reaction (SILAR) method. We show that controlling temperature at which SILAR is performed is critical to obtain a higher and more uniform coverage of PbS QDs over a mesoporous TiO2 film. The deposition of a CdS inter-layer between TiO2 and PbS is found to be an effective means of ensuring high photocurrent and stability. Not only does this modification improve the light absorption capability of the photoanode, but it also has a significant effect on charge recombination and electron injection efficiency at the PbS/TiO2 interface according to our in-depth study using electrochemical impedance spectroscopy (EIS). The implication of subtle changes in the interfacial events via modified SILAR conditions for PbS-sensitized solar cells is discussed.

  13. Baseline Surface Radiation Network (BSRN) quality control of solar radiation data on the Gangneung-Wonju National University radiation station

    NASA Astrophysics Data System (ADS)

    Zo, Il-Sung; Jee, Joon-Bum; Kim, Bu-Yo; Lee, Kyu-Tae

    2017-02-01

    Gangneung-Wonju National University (GWNU) radiation station has been collecting data on global, direct, and diffuse solar radiation since 2011. We conducted a quality control (QC) assessment of GWNU data collected between 2012 and 2014, using procedures outlined by the Baseline Surface Radiation Network (BSRN). The QC process involved the comparison of observations, the correction of observational equipment, the examination of physically possible limits, and the comparative testing of observations and model calculations. Furthermore, we performed a shading check of the observational environment around the GWNU solar station. For each solar radiation element (observed every minute), we performed a QC check and investigated any flagged problems. 98.31% of the data were classified as good quality, while the remaining 1.69% were flagged as bad quality based on the shading check and comparison tests. We then compared the good-quality data to the global solar radiation data observed at the Gangwon Regional Office of Meteorology (GROM). After performing this comparison, the determination coefficient (R2; 0.98) and standard deviation (SD; 0.92 MJ m-2) increased compared to those computed before the QC check (0.97 and 1.09 MJ m-2). Even considering the geographical differences and weather effects between the two stations, these results are statistically significant. However, we also confirmed that the quality of the GROM data deteriorated in relation to weather conditions because of poor maintenance. Hence, we conclude that good-quality observational data rely on the maintenance of both observational equipment and the surrounding environment under optimal conditions.

  14. Self-assembly method for controlling spatial frequency response of plasmonic back reflectors in organic thin-film solar cells

    NASA Astrophysics Data System (ADS)

    Okamoto, Takayuki; Shinotsuka, Kei; Kawamukai, Etsuko; Ishibashi, Koji

    2017-01-01

    We propose a novel colloidal lithography technique that uses a mixture of colloidal particles with a few different diameters. This technique can be used for fabricating quasi-random nanostructures whose k-space spectra can be easily controlled by using an appropriate combination of particles. We introduced such nanostructures into the back reflectors of organic thin-film solar cells, where they serve as plasmonic back reflectors for recycling the nonabsorbed transmitted light into surface plasmons. The obtained photon-to-current efficiency was enhanced by 14-20% compared with that of a flat cell.

  15. Nonlinear modeling and study for control of the research spacecraft with solar sail

    NASA Astrophysics Data System (ADS)

    Khabibullin, Roman; Starinova, Olga

    2017-01-01

    This paper outlines the mathematical motion model of the research spacecraft that uses solar sail instead of an engine and a propellant. The mathematical motion model for solar sail spacecraft is formulated and described. The work considers the mathematical motion model within the heliocentric system of coordinates. The best way to assess the reasonableness of the mathematical model is the using model in motion simulation process. On the basis of the formulated mathematical model the special software complex for interplanetary transfer simulation is developed. Especially, the mission of the transfer of the spacecraft from the Earth's orbit to the potentially hazardous asteroid is simulated. The obtained results during simulation demonstrate correctness and feasibility of the considered mathematical motion model.

  16. Control of light absorption in organic solar cells using semi-transparent metal electrodes

    NASA Astrophysics Data System (ADS)

    Neutzner, Stefanie; van de Groep, Jorik; Bakulin, Artem A.; Bakker, Huib J.

    2013-09-01

    In this contribution we combine optical modeling and device fabrication/characterization techniques to demonstrate that semitransparent metal electrodes can improve light harvesting in organic photovoltaic (OPV) devices. We show that inverted P3HT:PCBM solar cells using a thin ~8 nm silver film as a front electrode outperform the ITO-based devices, despite the lower transmittance of silver films in comparison to ITO. The variation of silver thickness allows tailoring the field distribution inside the cell, which leads to a broad resonance window where the absorption is enhanced. Thereby the short-circuit current was increased by 84% and the solar-cell efficiency was doubled. These results show that semitransparent metal electrodes can be efficiently used for light trapping and also form a very promising alternative to ITO in OPV devices. The stacked silver electrodes used in this work are flexible and can be easily produced on a large scale, including printing techniques.

  17. Project management and control of the Daniel K. Inouye Solar Telescope

    NASA Astrophysics Data System (ADS)

    McMullin, Joseph P.; McVeigh, William; Warner, Mark; Rimmele, Thomas R.; Craig, Simon C.; Ferayorni, Andrew; Goodrich, Bret D.; Hubbard, Robert P.; Hunter, Rex; Jeffers, Paul; Johansson, Erik; Marshall, Heather; McBride, William R.; Phelps, LeEllen; Shimko, Steve; Tritschler, Alexandra; Williams, Timothy R.; Wöger, Friedrich

    2016-08-01

    We provide a brief update on the construction status of the Daniel K. Inouye Solar Telescope, a $344M, 10-year construction project to design and build the world's largest solar physics observatory. We review the science drivers along with the challenges in meeting the evolving scientific needs over the course of the construction period without jeopardizing the systems engineering and management realization. We review the tools, processes and performance measures in use in guiding the development as well as the risks and challenges as the project transitions through various developmental phases. We elaborate on environmental and cultural compliance obligations in building in Hawai'i. We discuss the broad "lessons learned". Finally, we discuss the project in the context of the evolving management oversight within the US (in particular under the NSF).

  18. Evaluation of flat-plate collector efficiency under controlled conditions in a solar simulator

    NASA Technical Reports Server (NTRS)

    Johnson, S. M.; Simon, F. F.

    1976-01-01

    The measured thermal efficiencies of 35 collectors tested with a solar simulator, along with the correlation equations used to generalize the data, are presented in this report. The single correlation used is shown to apply to all the different types of collectors tested, including one with black paint and one cover, one with a selective surface coating and two covers, and an evacuated-tube collector. The test and correlation technique is also modified by using a shield so that collectors larger than the simulator test area can also be tested. This technique was verified experimentally for a shielded collector for which the collector shielded area was 31% of the solar simulator radiation area. A table lists all the collectors tested, the collector areas, and the experimental constants used to correlate the data for each collector.

  19. Evaluation of flat-plate collector efficiency under controlled conditions in a solar simulator

    NASA Technical Reports Server (NTRS)

    Johnson, S. M.; Simon, F. F.

    1976-01-01

    The measured thermal efficiencies of 35 collectors tested with a solar simulator, along with the correlation equations used to generalize the data, are presented. The single correlation used is shown to apply to all the different types of collectors tested, including one with black paint and one cover, one with a selective surface coating and two covers, and an evacuated-tube collector. The test and correlation technique is also modified by using a shield so that collectors larger than the simulator test area can also be tested. This technique was verified experimentally for a shielded collector for which the collector shielded area was 31% of the solar simulator radiation area. A table lists all the collectors tested, the collector areas, and the experimental constants used to correlate the data for each collector.

  20. Solar collection

    NASA Astrophysics Data System (ADS)

    Cole, S. I.

    1984-08-01

    Solar dishes, photovoltaics, passive solar building and solar hot water systems, Trombe walls, hot air panels, hybrid solar heating systems, solar grain dryers, solar greenhouses, solar hot water worhshops, and solar workshops are discussed. These solar technologies are applied to residential situations.

  1. To develop a dynamic model of a collector loop for purpose of improved control of solar heating and cooling. Final technical report. [TRNSYS code

    SciTech Connect

    Herczfeld, P R; Fischl, R

    1980-01-01

    The program objectives were to (1) assess the feasibility of using the TRNSYS computer code for solar heating and cooling control studies and modify it wherever possible, and (2) develop a new dynamic model of the solar collector which reflects the performance of the collector under transient conditions. Also, the sensitivity of the performance of this model to the various system parameters such as collector time constants, flow rates, turn-on and turn-off temperature set points, solar insolation, etc., was studied. Results are presented and discussed. (WHK)

  2. Radiation in Space and Its Control of Equilibrium Temperatures in the Solar System

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.

    2004-01-01

    The problem of determining equilibrium temperatures for reradiating surfaces in space vacuum was analyzed and the resulting mathematical relationships were incorporated in a code to determine space sink temperatures in the solar system. A brief treatment of planetary atmospheres is also included. Temperature values obtained with the code are in good agreement with available spacecraft telemetry and meteorological measurements for Venus and Earth. The code has been used in the design of space power system radiators for future interplanetary missions.

  3. Solar Wind and IMF Control of Large-Scale Ionospheric Currents and Their Time Variations

    NASA Astrophysics Data System (ADS)

    Juusola, L.; Kauristie, K.; Tanskanen, E.; Partamies, N.; Viljanen, A.; Andréeová, K.; van de Kamp, M.; Vanhamäki, H.; Milan, S. E.; Lester, M.; Grocott, A.; Imber, S. M.

    2014-12-01

    Patterns of high-latitude ionospheric currents are a manifestation of the solar wind-magnetosphere-ionosphere coupling. Rapid variations of the currents are associated with geomagnetically induced currents (GIC) in technological conductor systems and displays of bright, diverse auroras. One advantage of a ground-based magnetometer network over a low-orbit satellite is the possibility to distinguish between temporal and spatial variations in the data. Although ground magnetic field data can only yield distributions of ionospheric equivalent currents instead of the full horizontal and field-aligned current density, estimates for these can be obtained, under certain assumptions. We use data (1994-2013) from the ground-based IMAGE magnetometer network to derive statistical distributions of the large-scale ionospheric equivalent current density and its time-derivative as well as estimates for the field-aligned current density. These are compared with and validated against horizontal and field-aligned current density distributions obtained from low-orbit CHAMP satellite magnetic field data (2000-2010) and convection maps obtained from SuperDARN radar data (2000-2010). The ground-based distributions reveal a strong dependence of the dayside variations on radial interplanetary magnetic field (IMF) orientation and solar wind speed. The spatial distribution of enhanced nightside activity agrees with that of the average substorm bulge and depends on solar wind energy input into the magnetosphere. The most intense time variation events are related to substorm activity and occur on the nightside.

  4. Refractive index and solubility control of para-cymene solutions for index-matched fluid-structure interaction studies

    NASA Astrophysics Data System (ADS)

    Fort, Charles; Fu, Christopher D.; Weichselbaum, Noah A.; Bardet, Philippe M.

    2015-12-01

    To deploy optical diagnostics such as particle image velocimetry or planar laser-induced fluorescence (PLIF) in complex geometries, it is beneficial to use index-matched facilities. A binary mixture of para-cymene and cinnamaldehyde provides a viable option for matching the refractive index of acrylic, a common material for scaled models and test sections. This fluid is particularly appropriate for large-scale facilities and when a low-density and low-viscosity fluid is sought, such as in fluid-structure interaction studies. This binary solution has relatively low kinematic viscosity and density; its use enables the experimentalist to select operating temperature and to increase fluorescence signal in PLIF experiments. Measurements of spectral and temperature dependence of refractive index, density, and kinematic viscosity are reported. The effect of the binary mixture on solubility control of Rhodamine 6G is also characterized.

  5. Density-controlled ZnO/TiO2 nanocomposite photoanode for improving dye-sensitized solar cells performance

    NASA Astrophysics Data System (ADS)

    Yao, Jimmy; Lin, Chih-Min; Yin, Stuart (.

    2015-03-01

    Dye-sensitized solar cells (DSSCs) via ZnO/TiO2 nanocomposite photoanode with density-controlled abilities are presented in this paper. This nanocomposite photoanode is composed of TiO2 nanoparticles dispersed into densitycontrolled vertically aligned ZnO-TiO2 core-shell nanorod arrays. The density-controlled ZnO-TiO2 core-shell nanorod arrays were synthesized directly onto fluorine-doped tin oxide (FTO) substrates using an innovative two-step wet chemical route. First, the density-controlled ZnO nanorod arrays were formed by applying a ZnO hydrothermal process from a TiO2 nanocrystals template. Second, the ZnO-TiO2 core-shell nanorod arrays were formed by depositing a TiO2 shell layer from a sol-gel process. The major advantages of a density-controlled ZnO/TiO2 nanocomposite photoanode include (1) providing a better diffusion path from ZnO nanorod arrays and (2) reducing the recombination loss by introducing an energy barrier layer TiO2 conformal shell coating. To validate the advantages of a density-controlled ZnO/TiO2 nanocomposite photoanode, DSSCs based on a ZnO/TiO2 nanocomposite photoanode were fabricated, in which N719 dye was used. The average dimensions of the ZnO nanorod arrays were 20 μm and 650 nm for the length and the diameter, respectively, while the designated spacing between each nanorod was around 5 μm. The performance of the solar cell was tested by using a standard AM 1.5 solar simulator from Newport Corporation. The experimental results confirmed that an open-circuit voltage, 0.93 V, was achieved, which was much higher than the conventional TiO2 nanoparticles thin film structure for the same thickness. Thus, density-controlled ZnO/TiO2 nanocomposite photoanodes could improve the performance of DSSCs by offering a better electron diffusion path.

  6. Role of 4- tert -Butylpyridine as a Hole Transport Layer Morphological Controller in Perovskite Solar Cells

    SciTech Connect

    Wang, Shen; Sina, Mahsa; Parikh, Pritesh; Uekert, Taylor; Shahbazian, Brian; Devaraj, Arun; Meng, Ying Shirley

    2016-09-14

    Hybrid organic-inorganic materials for high efficiency, low cost photovoltaic devices have seen rapid progress since the introduction of lead based perovskites and solid-state hole transport layers. Although majority of the materials used for perovskite solar cells (PSC) are introduced from dye-sensitized solar cells (DSSCs), the presence of a perovskite capping layer as opposed to a single dye molecule (in DSSCs) changes the interactions between the various layers in perovskite solar cells. 4-tert-butylpyridine (tBP), commonly used in PSCs, is assumed to function as a charge recombination inhibitor, similar to DSSCs. However, the presence of a perovskite capping layer calls for a re-evaluation of its function in PSCs. Using TEM (transmission electron microscopy), we first confirm the role of tBP as a HTL morphology controller in PSCs. Our observations suggest that tBP significantly improves the uniformity of the HTL and avoids accumulation of Li salt. We also study degradation pathways by using FTIR (Fourier transform infrared spectroscopy) and APT (atom probe tomography) to investigate and visualize in 3-dimensions the moisture content associated with the Li salt. Long term effects, over 1000 hours, due to evaporation of tBP have also been studied. Based on our findings, a PSC failure mechanism associated with the morphological change of the HTL is proposed. tBP, the morphology controller in HTL, plays a key role in this process and thus this study highlights the need for additive materials with higher boiling points for consistent long term performance of PSCs.

  7. Bi-Sn alloy catalyst for simultaneous morphology and doping control of silicon nanowires in radial junction solar cells

    SciTech Connect

    Yu, Zhongwei; Lu, Jiawen; Qian, Shengyi; Xu, Jun; Xu, Ling; Wang, Junzhuan; Shi, Yi; Chen, Kunji; Yu, Linwei E-mail: linwei.yu@polytechnique.edu

    2015-10-19

    Low-melting point metals such as bismuth (Bi) and tin (Sn) are ideal choices for mediating a low temperature growth of silicon nanowires (SiNWs) for radial junction thin film solar cells. The incorporation of Bi catalyst atoms leads to sufficient n-type doping in the SiNWs core that exempts the use of hazardous dopant gases, while an easy morphology control with pure Bi catalyst has never been demonstrated so far. We here propose a Bi-Sn alloy catalyst strategy to achieve both a beneficial catalyst-doping and an ideal SiNW morphology control. In addition to a potential of further growth temperature reduction, we show that the alloy catalyst can remain quite stable during a vapor-liquid-solid growth, while providing still sufficient n-type catalyst-doping to the SiNWs. Radial junction solar cells constructed over the alloy-catalyzed SiNWs have demonstrated a strongly enhanced photocurrent generation, thanks to optimized nanowire morphology, and largely improved performance compared to the reference samples based on the pure Bi or Sn-catalyzed SiNWs.

  8. Solar control of the Martian magnetic topology: Implications from model-data comparisons

    NASA Astrophysics Data System (ADS)

    Ulusen, D.; Luhmann, J. G.; Ma, Y.; Brain, D. A.

    2016-09-01

    One of the goals of the upcoming MAVEN mission to Mars is to investigate the effects of the crustal remanent fields on the solar wind plasma interaction and the upper atmosphere. The MGS Electron Reflectometer and magnetometer observations can be used to test the idea that, if the future data from the electron spectrometer (SWEA) are separated for the two prevalent interplanetary field orientations (Parker spirals 'toward' and 'away' from the Sun), one may be able to detect specific differences in the pattern of locations of open magnetic fields (where photoelectrons can escape from Mars' ionosphere into space), as well as patterns of photoelectrons in the Martian magnetotail. We use a pair of BATS-R-US MHD model results of the Mars-solar wind interaction, in a manner similar to that tested by Liemohn et al. in 2006 on Mars Express ELS electron data, to define these patterns of expected photo-electron detections on a global scale. Those cases have the strongest southern hemisphere crustal fields at noon or midnight, a matter of importance in such investigations because these patterns will be sensitive to the local time of those fields. We compare some MGS data-based maps of the time periods selected for their open field signatures in the pitch angle distributions and energy spectra, and separated by interplanetary field orientation inferred from Mars magnetosheath observations. This exercise illustrates the power (and necessity) of the global model comparisons as a means of interpreting the very complex Mars-solar wind interaction and its effects.

  9. Gradient zone-boundary control in salt-gradient solar ponds

    DOEpatents

    Hull, J.R.

    1982-09-29

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizeable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  10. Critical kinetic control of non-stoichiometric intermediate phase transformation for efficient perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Rong, Yaoguang; Venkatesan, Swaminathan; Guo, Rui; Wang, Yanan; Bao, Jiming; Li, Wenzhi; Fan, Zhiyong; Yao, Yan

    2016-06-01

    Organometal trihalide perovskites (OTP) have attracted significant attention as a low-cost and high-efficiency solar cell material. Due to the strong coordination between lead iodide (PbI2) and dimethyl sulfoxide (DMSO) solvent, a non-stoichiometric intermediate phase of MA2Pb3I8(DMSO)2 (MA = CH3NH3+) usually forms in the one-step deposition method that plays a critical role in attaining high power conversion efficiency. However, the kinetic understanding of how the non-stoichiometric intermediate phase transforms during thermal annealing is currently absent. In this work, we investigated such a phase transformation and provided a clear picture of three phase transition pathways as a function of annealing conditions. The interdiffusion of MAI and DMSO varies strongly with the annealing temperature and time, thus determining the final film composition and morphology. A surprising finding reveals that the best performing cells contain ~18% of the non-stoichiometric intermediate phase, instead of pure phase OTP. The presence of such an intermediate phase enables smooth surface morphology and enhances the charge carrier lifetime. Our results highlight the importance of the intermediate phase growth kinetics that could lead to large-scale production of efficient solution processed perovskite solar cells.Organometal trihalide perovskites (OTP) have attracted significant attention as a low-cost and high-efficiency solar cell material. Due to the strong coordination between lead iodide (PbI2) and dimethyl sulfoxide (DMSO) solvent, a non-stoichiometric intermediate phase of MA2Pb3I8(DMSO)2 (MA = CH3NH3+) usually forms in the one-step deposition method that plays a critical role in attaining high power conversion efficiency. However, the kinetic understanding of how the non-stoichiometric intermediate phase transforms during thermal annealing is currently absent. In this work, we investigated such a phase transformation and provided a clear picture of three phase transition

  11. Flight Mechanics and Control Requirements for a Modular Solar Electric Tug Operating in Earth-Moon Space

    NASA Astrophysics Data System (ADS)

    Woodcock, Gordon; Wingo, Dennis

    2006-01-01

    A modular design for a solar-electric tug was analyzed to establish flight control requirements and methods. Thrusters are distributed around the periphery of the solar array. This design enables modules to be berthed together to create a larger system from smaller modules. It requires a different flight mode than traditional design and a different thrust direction scheme, to achieve net thrust in the desired direction, observe thruster pointing constraints that avoid plume impingement on the tug, and balance moments. The array is perpendicular to the Sun vector for maximum electric power. The tug may maintain a constant inertial attitude or rotate around the Sun vector once per orbit. Either non-rotating or constant angular velocity rotation offers advantages over the conventional flight mode, which has highly variable roll rates. The baseline single module has 12 thrusters: two 2-axis gimbaling main thrusters, one at each ``end'', and two back-to-back Z axis thrusters at each corner of the array. Thruster pointing and throttling were optimized to maximize net thrust effectiveness while observing constraints. Control design used a spread sheet with Excel Solver to calculate nominal thruster pointing and throttling. These results are used to create lookup tables. A conventional control system generates a thruster pointing and throttling overlay on the nominals to maintain active attitude control. Gravity gradients can cause major attitude perturbations during occultation periods if thrust is off during these periods. Thrust required to maintain attitude is about 4% of system rated power. This amount of power can be delivered by a battery system, avoiding the performance penalty if chemical propulsion thrusters were used to maintain attitude.

  12. Sodium-Doped Molybdenum Targets for Controllable Sodium Incorporation in CIGS Solar Cells

    SciTech Connect

    Mansfield, L. M.; Repins, I. L.; Glynn, S.; Carducci, M. D.; Honecker, D. M.; Pankow, J.l W.; Young, M. R.; DeHart, C.; Sundaramoorthy, R.; Beall, C. L.; To, B.

    2011-01-01

    The efficiency of Cu(In, Ga)Se{sub 2} (CIGS) solar cells is enhanced when Na is incorporated in the CIGS absorber layer. This work examines Na incorporation in CIGS utilizing Na-doped Mo sputtered from targets made with sodium molybdate-doped (MONA) powder. Mo:Na films with varying thicknesses were sputtered onto Mo-coated borosilicate glass (BSG) or stainless steel substrates for CIGS solar cells. By use of this technique, the Na content of CIGS can be varied from near-zero to higher than that obtained from a soda-lime glass (SLG) substrate. Targets and deposition conditions are described. The doped Mo films are analyzed, and the resulting devices are compared to devices fabricated on Mo-coated SLG as well as Mo-coated BSG with NaF. Completed devices utilizing MONA exceeded 15.7% efficiency without anti-reflective coating, which was consistently higher than devices prepared with the NaF precursor. Strategies for minimizing adhesion difficulties are presented.

  13. Sodium-Doped Molybdenum Targets for Controllable Sodium Incorporation in CIGS Solar Cells: Preprint

    SciTech Connect

    Mansfield, L. M.; Repins, I. L.; Glynn, S.; Carducci, M. D.; Honecker, D. M.; Pankow, J.; Young, M.; DeHart, C.; Sundaramoorthy, R.; Beall, C. L.; To, B.

    2011-07-01

    The efficiency of Cu(In,Ga)Se2 (CIGS) solar cells is enhanced when Na is incorporated in the CIGS absorber layer. This work examines Na incorporation in CIGS utilizing Na-doped Mo sputtered from targets made with sodium molybdate-doped (MONA) powder. Mo:Na films with varying thicknesses were sputtered onto Mo-coated borosilicate glass (BSG) or stainless steel substrates for CIGS solar cells. By use of this technique, the Na content of CIGS can be varied from near-zero to higher than that obtained from a soda-lime glass (SLG) substrate. Targets and deposition conditions are described. The doped Mo films are analyzed, and the resulting devices are compared to devices fabricated on Mo-coated SLG as well as Mo-coated BSG with NaF. Completed devices utilizing MONA exceeded 15.7% efficiency without anti-reflective coating, which was consistently higher than devices prepared with the NaF precursor. Strategies for minimizing adhesion difficulties are presented.

  14. Rapid thermal processing of high-efficiency silicon solar cells with controlled in-situ annealing

    SciTech Connect

    Doshi, P.; Rohatgi, A.; Ropp, M.; Chen, Z.; Ruby, D.; Meier, D.L.

    1995-01-01

    Silicon solar cell efficiencies of 17.1%, 16.4%, 14.8%, and 14.9% have been achieved on FZ, Cz, multicrystalline (mc-Si), and dendritic web (DW) silicon, respectively, using simplified, cost-effective rapid thermal processing (RTP). These represent the highest reported efficiencies for solar cells processed with simultaneous front and back diffusion with no conventional high-temperature furnace steps. Appropriate diffusion temperature coupled with the added in-situ anneal resulted in suitable minority-carrier lifetime and diffusion profiles for high-efficiency cells. The cooling rate associated with the in-situ anneal can improve the lifetime and lower the reverse saturation current density (J{sub 0}), however, this effect is material and base resistivity specific. PECVD antireflection (AR) coatings provided low reflectance and efficient front surface and bulk defect passivation. Conventional cells fabricated on FZ silicon by furnace diffusions and oxidations gave an efficiency of 18.8% due to greater short wavelength response and lower J{sub 0}.

  15. Solar-terrestrial effect controls seismic activity to a large extent (Invited)

    NASA Astrophysics Data System (ADS)

    Duma, G.

    2010-12-01

    Several observational results and corresponding publications in the 20 century indicate that earthquakes in many regions happen systematically in dependence on the time of day and on the season as well. In the recent decade, studies on this topic have also been intensively performed at the Central Institute for Meteorology and Geodynamics (ZAMG), Vienna. Any natural effect on Earth which systematically appears at certain hours of the day or at a special season can solely be caused by a solar or lunar influence. And actually, statistic results on seismic activity reveal a correlation with the solar cycles. Examples of this seismic performance are shown. To gain more clarity about these effects, the three-hour magnetic index Kp, which characterizes the magnetic field disturbances, mainly caused by the solar particle radiation, the solar wind, was correlated with the seismic energy released by earthquakes over decades. Kp is determined from magnetic records of 13 observatories worldwide and continuously published by ISGI, France. It is demonstrated that a highly significant correlation between the geomagnetic index Kp and the annual seismic energy release in regions at latitudes between 35 and 60° N exists. Three regions of continental size were investigated, using the USGS (PDE) earthquake catalogue data. In the period 1974-2009 the Kp cycle periods range between 9 and 12 years, somewhat different to the sunspot number cycles of 11 years. Seismicity follows the Kp cycles with high coincidence. A detailed analysis of this correlation for N-America reveals, that the sum of released energy by earthquakes per year changes by a factor up to 100 with Kp. It is shown that during years of high Kp there happen e.g. 1 event M7, 4 events M6 and 30 events M5 per year, instead of only 10 events M5 in years with lowest Kp. Almost the same relation appears in other regions of continental size, with the same significance. The seismicity in S-America clearly follows the Kp cycles

  16. Solar Physics Topics in High School: Analysis of a Course with Practical Activities at Dietrich Schiel Observatory. (Spanish Title: Temas de Física Solar Para Estudiantes de Escuelas Secundarias: un Análisis de un Curso con Enfoque Práctico en el Observatorio Dietrich Schiel.) Tópicos de Física Solar no Ensino Médio: Análise de um Curso com Atividades Práticas no Observatório Dietrich Schiel

    NASA Astrophysics Data System (ADS)

    Calbo Aroca, Silvia; Donizete Colombo, Pedro, Jr.; Celestino Silva, Cibelle

    2012-12-01

    This work analyses results obtained in a solar physics course for high school students promoted at the Dietrich Schiel Observatory of the University of São Paulo (USP). The course was elaborated by the authors with the intention of investigating student's concepts about the Sun, teaching topics of modern physics related to the Sun and providing students with knowledge about our star as well. The methodology of data gathering consisted of audio and video records of classes and of semi-structured interviews, and analysis of answers to written questionnaires. The results showed that most high school students conceived the Sun as made of fire, while sunspots were thought to be holes in the Sun. Even though some students did know that a spectrum is formed using a prism or diffraction grating, most of them ignored the nature of the observed spectral lines. Through the course, this topic was developed by means of a practical approach with solar and lamp spectra observations. The results obtained in the course point to the importance of science centers as partners in formal education. In this specific case, the Solar Room at the Dietrich Schiel Observatory is as a favorable environment for teaching modern physics in high school. Este artículo analiza los resultados obtenidos en un curso sobre la física solar, auspiciado por el Observatorio Dietrich Schiel de la USP para estudiantes de las escuelas secundarias. El curso fue diseñado por los autores con la intención de investigar las concepciones sobre el sol, enseñar temas relacionados con la física moderna del Sol y conocimientos generales sobre el astro rey. La metodología utilizada para la recolección de datos consistió en grabar, en audio y video, las clases, las entrevistas semi-estructuradas y las respuestas a los cuestionarios escritos. Los resultados mostraron que la mayoría de los participantes conciben el Sol como constituido por fuego y las manchas solares en la superficie solar como agujeros. Aunque

  17. Control system development for a 1 MW/e/ solar thermal power plant

    NASA Technical Reports Server (NTRS)

    Daubert, E. R.; Bergthold, F. M., Jr.; Fulton, D. G.

    1981-01-01

    The point-focusing distributed receiver power plant considered consists of a number of power modules delivering power to a central collection point. Each power module contains a parabolic dish concentrator with a closed-cycle receiver/turbine/alternator assembly. Currently, a single-module prototype plant is under construction. The major control system tasks required are related to concentrator pointing control, receiver temperature control, and turbine speed control. Attention is given to operational control details, control hardware and software, and aspects of CRT output display.

  18. Plasma surrounding the global heliosphere at large distances controlled by the solar cycle

    NASA Astrophysics Data System (ADS)

    Dialynas, Konstantinos; Krimigis, Stamatios; Mitchell, Donald; Decker, Robert; Roelof, Edmond

    2016-04-01

    The past decade can be characterized by a series of key, groundbreaking remote energetic neutral atom (ENA) images (INCA, IBEX) and in-situ ion (Voyager 1 & 2) observations concerning the characteristics and interactions of the heliosphere with the Local Interstellar Medium (LISM). Voyagers 1 and 2 (V1, V2) discovered the reservoir of ions and electrons that constitute the heliosheath (HS) after crossing the termination shock (TS) 35deg north and 32deg south of the ecliptic plane at 94 and 84 astronomical units (1 AU= 1.5 x108 km), respectively. The in situ measurements by each Voyager were placed in a global context by remote sensing images using ENA obtained with the Ion and Neutral Camera (INCA) onboard Cassini orbiting Saturn. The ENA images contain a 5.2-55 keV hydrogen (H) ENA region (Belt) that loops through the celestial sphere and contributes to balancing the pressure of the interstellar magnetic field (ISMF). The success of any future mission with dedicated ENA detectors (e.g. the IMAP mission), highly depends on the antecedent understanding of the details of the plasma processes in the Heliosphere as revealed by remote sensing of the plasma environment characteristics. Therefore, we address here one of the remaining and most important questions: "Where do the 5-55 keV ENAs that INCA measures come from?". We analyzed INCA all-sky maps from 2003 to 2015 and compare the solar cycle (SC) variation of the ENAs in both the nose (upstream) and anti-nose (downstream) directions with the intensities of > 30 keV ions (source of ENA through charge exchange-CE with H) measured in-situ by V1 and V2, in overlapping energy bands ~30-55 keV. ENA intensities decrease during the declining phase of SC23 by ~x3 from 2003 to 2011 but recover through 2014 (SC24); similarly, V1 and V2 ion intensities also decrease and then recover through 2014. The similarity of time profiles of remotely sensed ENA and locally measured ions are consistent with (a) ENA originating in the HS

  19. Solar astronomy

    NASA Technical Reports Server (NTRS)

    Rosner, Robert; Noyes, Robert; Antiochos, Spiro K.; Canfield, Richard C.; Chupp, Edward L.; Deming, Drake; Doschek, George A.; Dulk, George A.; Foukal, Peter V.; Gilliland, Ronald L.

    1991-01-01

    An overview is given of modern solar physics. Topics covered include the solar interior, the solar surface, the solar atmosphere, the Large Earth-based Solar Telescope (LEST), the Orbiting Solar Laboratory, the High Energy Solar Physics mission, the Space Exploration Initiative, solar-terrestrial physics, and adaptive optics. Policy and related programmatic recommendations are given for university research and education, facilitating solar research, and integrated support for solar research.

  20. Examining System-Wide Impacts of Solar PV Control Systems with a Power Hardware-in-the-Loop Platform

    SciTech Connect

    Williams, Tess L.; Fuller, Jason C.; Schneider, Kevin P.; Palmintier, Bryan; Lundstrom, Blake; Chakraborty, Sudipta

    2014-10-11

    High penetration levels of distributed solar PV power generation can lead to adverse power quality impacts such as excessive voltage rise, voltage flicker, and reactive power values that result in unacceptable voltage levels. Advanced inverter control schemes have been proposed that have the potential to mitigate many power quality concerns. However, closed-loop control may lead to unintended behavior in deployed systems as complex interactions can occur between numerous operating devices. In order to enable the study of the performance of advanced control schemes in a detailed distribution system environment, a Hardware-in-the-Loop (HIL) platform has been developed. In the HIL system, GridLAB-D, a distribution system simulation tool, runs in real-time mode at the Pacific Northwest National Laboratory (PNNL) and supplies power system parameters at a point of common coupling to hardware located at the National Renewable Energy Laboratory (NREL). Hardware inverters interact with grid and PV simulators emulating an operational distribution system and power output from the inverters is measured and sent to PNNL to update the real-time distribution system simulation. The platform is described and initial test cases are presented. The platform is used to study the system-wide impacts and the interactions of controls applied to inverters that are integrated into a simulation of the IEEE 8500-node test feeder, with inverters in either constant power factor control or active volt/VAR control. We demonstrate that this HIL platform is well-suited to the study of advanced inverter controls and their impacts on the power quality of a distribution feeder. Additionally, the results from HIL are used to validate GridLAB-D simulations of advanced inverter controls.

  1. Simulated Solar Flare X-Ray and Thermal Cycling Durability Evaluation of Hubble Space Telescope Thermal Control Candidate Replacement Materials

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.; Banks, Bruce A.; Sechkar, Edward A.; Scheiman, David A.

    1998-01-01

    During the Hubble Space Telescope (HST) second servicing mission (SM2), astronauts noticed that the multilayer insulation (MLI) covering the telescope was damaged. Large pieces of the outer layer of MLI (aluminized Teflon fluorinated ethylene propylene (Al-FEP)) were torn in several locations around the telescope. A piece of curled up Al-FEP was retrieved by the astronauts and was found to be severely embrittled, as witnessed by ground testing. Goddard Space Flight Center (GSFC) organized a HST MLI Failure Review Board (FRB) to determine the damage mechanism of FEP in the HST environment, and to recommend replacement insulation material to be installed on HST during the third servicing mission (SM3) in 1999. Candidate thermal control replacement materials were chosen by the FRB and tested for environmental durability under various exposures and durations. This paper describes durability testing of candidate materials which were exposed to charged particle radiation, simulated solar flare x-ray radiation and thermal cycling under load. Samples were evaluated for changes in solar absorptance and tear resistance. Descriptions of environmental exposures and durability evaluations of these materials are presented.

  2. Perovskite/c-Si tandem solar cell with inverted nanopyramids: realizing high efficiency by controllable light trapping

    PubMed Central

    Shi, Dai; Zeng, Yang; Shen, Wenzhong

    2015-01-01

    Perovskite/c-Si tandem solar cells (TSCs) have become a promising candidate in recent years for achieving efficiency over 30%. Although general analysis has shown very high upper limits for such TSCs, it remains largely unclear what specific optical structures could best approach these limits. Here we propose the combination of perovskite/c-Si tandem structure with inverted nanopyramid morphology as a practical way of achieving efficiency above 31% based on realistic solar cell parameters. By full-field simulation, we have shown that an ultra-low surface reflectance can be achieved by tuning the pyramid geometry within the range of experimental feasibility. More importantly, we have demonstrated that the index-guided modes can be excited within the top cell layer by introducing a TCO interlayer that prevents coupling of guided light energy into the bottom cell. This light trapping scheme has shown superior performance over the Bragg stack intermediate reflector utilized in previous micropyramid-based TSCs. Finally, by controlling the coupling between the top and bottom cell through the thickness of the interlayer, current generation within the tandem can be optimized for both two- and four-terminal configurations, yielding efficiencies of 31.9% and 32.0%, respectively. These results have provided useful guidelines for the fabrication of perovskite/c-Si TSCs. PMID:26566176

  3. Controllable growth of dendritic ZnO nanowire arrays on a stainless steel mesh towards the fabrication of large area, flexible dye-sensitized solar cells.

    PubMed

    Dai, Hui; Zhou, Yong; Liu, Qi; Li, Zhengdao; Bao, Chunxiong; Yu, Tao; Zhou, Zhigang

    2012-09-07

    Well-defined ZnO nanowire (NW) arrays with controlled dendritic structures were successfully built on a stainless steel mesh and utilized as photoanodes for the fabrication of large-area, flexible dye-sensitized solar cells (DSSCs). The dendritic nanostructure proves favorable for the improvement of the overall light conversion efficiency of the DSSC. An optimized etching time for the affixion of ZnO seeds on the ZnO backbone of the dendritic "tree" and the controlled growth conditions of the branch NW are critical to achieve high conversion efficiency solar cells.

  4. Controllable growth of dendritic ZnO nanowire arrays on a stainless steel mesh towards the fabrication of large area, flexible dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Dai, Hui; Zhou, Yong; Liu, Qi; Li, Zhengdao; Bao, Chunxiong; Yu, Tao; Zhou, Zhigang

    2012-08-01

    Well-defined ZnO nanowire (NW) arrays with controlled dendritic structures were successfully built on a stainless steel mesh and utilized as photoanodes for the fabrication of large-area, flexible dye-sensitized solar cells (DSSCs). The dendritic nanostructure proves favorable for the improvement of the overall light conversion efficiency of the DSSC. An optimized etching time for the affixion of ZnO seeds on the ZnO backbone of the dendritic ``tree'' and the controlled growth conditions of the branch NW are critical to achieve high conversion efficiency solar cells.

  5. Control of thermal barrier performance by optimized nanoparticle size and experimental evaluation using a solar simulator

    NASA Astrophysics Data System (ADS)

    Gonome, Hiroki; Baneshi, Mehdi; Okajima, Junnosuke; Komiya, Atsuki; Yamada, Noboru; Maruyama, Shigenao

    2014-12-01

    An experimental investigation to evaluate the radiative properties of a selectively transparent thin coating on a substrate of a different material has been performed in order to evaluate its thermal behavior for applications where a low temperature at the surface exposed to the sun is desired. Copper (II) oxide (CuO) micro-particles have been used to create a pigmented coating on a paper substrate. The particle volume fraction and size have been optimized by the theoretical methodology. The spectral reflectance was measured using spectroscopy in the visible (VIS) and near-infrared (NIR) regions. The spectral emissivity was evaluated from the reflectance in IR region. The temperatures of the designed coatings and typical black paints are measured in a solar simulator. The temperature measurement was simulated by numerical analysis. The temperature of CuO coating on standard white paper was 10 °C lower than the ones of typical black paint while keeping the desired dark tone.

  6. Voltage controlling mechanisms in low resistivity silicon solar cells: A unified approach

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Swartz, C. K.; Hart, R. E.; Godlewski, M. P.

    1984-01-01

    An experimental technique capable of resolving the dark saturation current into its base and emitter components is used as the basis of an analysis in which the voltage limiting mechanisms were determined for a variety of high voltage, low resistivity silicon solar cells. The cells studied include the University of Florida hi-low emitter cell, the NASA and the COMSAT multi-step diffused cells, the Spire Corporation ion-implanted emitter cell, and the University of New South Wales MINMIS and MINP cells. The results proved to be, in general, at variance with prior expectations. Most surprising was the finding that the MINP and the MINMIS voltage improvements are due, to a considerable extent, to a previously unrecognized optimization of the base component of the saturation current. This result is substantiated by an independent analysis of the material used to fabricate these devices.

  7. Voltage controlling mechanisms in low resistivity silicon solar cells - A unified approach

    NASA Technical Reports Server (NTRS)

    Weizer, V. G.; Swartz, C. K.; Hart, R. E.; Godlewski, M. P.

    1984-01-01

    An experimental technique capable of resolving the dark saturation current into its base and emitter components is used as the basis of an analysis in which the voltage limiting mechanisms were determined for a variety of high voltage, low resistivity silicon solar cells. The cells studied include the University of Florida hi-low emitter cell, the NASA and the COMSAT multi-step diffused cells, the Spire Corporation ion-implanted emitter cell, and the University of New South Wales MINMIS and MINP cells. The results proved to be, in general, at variance with prior expectations. Most surprising was the finding that the MINP and the MINMIS voltage improvements are due, to a considerable extent, to a previously unrecognized optimization of the base component of the saturation current. This result is substantiated by an independent analysis of the material used to fabricate these devices.

  8. Solar Thermal Upper Stage Liquid Hydrogen Pressure Control Testing and Analytical Modeling

    NASA Technical Reports Server (NTRS)

    Olsen, A. D.; Cady, E. C.; Jenkins, D. S.; Chandler, F. O.; Grayson, G. D.; Lopez, A.; Hastings, L. J.; Flachbart, R. H.; Pedersen, K. W.

    2012-01-01

    The demonstration of a unique liquid hydrogen (LH2) storage and feed system concept for solar thermal upper stage was cooperatively accomplished by a Boeing/NASA Marshall Space Flight Center team. The strategy was to balance thermodynamic venting with the engine thrusting timeline during a representative 30-day mission, thereby, assuring no vent losses. Using a 2 cubic m (71 cubic ft) LH2 tank, proof-of-concept testing consisted of an engineering checkout followed by a 30-day mission simulation. The data were used to anchor a combination of standard analyses and computational fluid dynamics (CFD) modeling. Dependence on orbital testing has been incrementally reduced as CFD codes, combined with standard modeling, continue to be challenged with test data such as this.

  9. Nanoporous thermochromic VO₂ (M) thin films: controlled porosity, largely enhanced luminous transmittance and solar modulating ability.

    PubMed

    Cao, Xun; Wang, Ning; Law, Jia Yan; Loo, Say Chye Joachim; Magdassi, Shlomo; Long, Yi

    2014-02-18

    Vanadium dioxide is the most widely researched thermochromic material with a phase transition temperature (τ(c)) of around 68 °C, and its thermochromic performance can be enhanced by adding nanoporosity. Freeze-drying has been employed to fabricate nanostructures with different porosities from 16 to 45% by varying the prefreezing temperature and precursor concentration. The luminous transmittance (Tlum) and solar modulating ability (ΔTsol) are greatly enhanced as a result of increasing pore size and pore density. The freeze-dried sample with 7.5 mL of H2O2 precursor dip-coated at 300 mm/min gives the best combination of thermochromic properties (Tlum ≈ 50%, ΔTsol = 14.7%), which surpasses the best combined thermochromic performance reported to date that we are aware of (Tlum ≈ 41%, ΔTsol = 14.1%).

  10. Gimbals Drive and Control Electronics Design, Development and Testing of the LRO High Gain Antenna and Solar Array Systems

    NASA Technical Reports Server (NTRS)

    Chernyakov, Boris; Thakore, Kamal

    2010-01-01

    Launched June 18, 2009 on an Atlas V rocket, NASA's Lunar Reconnaissance Orbiter (LRO) is the first step in NASA's Vision for Space Exploration program and for a human return to the Moon. The spacecraft (SC) carries a wide variety of scientific instruments and provides an extraordinary opportunity to study the lunar landscape at resolutions and over time scales never achieved before. The spacecraft systems are designed to enable achievement of LRO's mission requirements. To that end, LRO's mechanical system employed two two-axis gimbal assemblies used to drive the deployment and articulation of the Solar Array System (SAS) and the High Gain Antenna System (HGAS). This paper describes the design, development, integration, and testing of Gimbal Control Electronics (GCE) and Actuators for both the HGAS and SAS systems, as well as flight testing during the on-orbit commissioning phase and lessons learned.

  11. Design, Operation, and Controlled-Island Operation of the U.S. Department of Energy Solar Decathlon 2013 Microgrid

    SciTech Connect

    Kurnik, C.; Butt, R. S.; Metzger, I.; Lavrova, O.; Patibandla, S.; Wagner, V.; Frankosky, M.; Wiegand, G.

    2015-04-22

    This document reports on the design and operation of a high-capacity and high-penetration-ratio microgrid, which consists of 19 photovoltaic-powered residential houses designed by collegiate teams as part of their participation in the U.S. Department of Energy Solar Decathlon 2013. The microgrid was interconnected with the local utility, and resulting net-power and power-quality events were recorded in high detail (1-minute data sampling or better). Also, a controlled-island operation test was conducted to evaluate the microgrid response to additional events such as increased loads (e.g., from electric vehicles) and bypassing of voltage regulators. This temporary ground-laid microgrid was stable under nominal and island-operation conditions; adverse weather and loads did not lead to power-quality degradation.

  12. The Effect of Reaction Control System Thruster Plume Impingement on Orion Service Module Solar Array Power Production

    NASA Technical Reports Server (NTRS)

    Bury, Kristen M.; Kerslake, Thomas W.

    2008-01-01

    NASA's new Orion Crew Exploration Vehicle has geometry that orients the reaction control system (RCS) thrusters such that they can impinge upon the surface of Orion's solar array wings (SAW). Plume impingement can cause Paschen discharge, chemical contamination, thermal loading, erosion, and force loading on the SAW surface, especially when the SAWs are in a worst-case orientation (pointed 45 towards the aft end of the vehicle). Preliminary plume impingement assessment methods were needed to determine whether in-depth, timeconsuming calculations were required to assess power loss. Simple methods for assessing power loss as a result of these anomalies were developed to determine whether plume impingement induced power losses were below the assumed contamination loss budget of 2 percent. This paper details the methods that were developed and applies them to Orion's worst-case orientation.

  13. A Novel Hybrid Statistical Particle Swarm Optimization for Multimodal Functions and Frequency Control of Hybrid Wind-Solar System

    NASA Astrophysics Data System (ADS)

    Verma, Harish Kumar; Jain, Cheshta

    2016-09-01

    In this article, a hybrid algorithm of particle swarm optimization (PSO) with statistical parameter (HSPSO) is proposed. Basic PSO for shifted multimodal problems have low searching precision due to falling into a number of local minima. The proposed approach uses statistical characteristics to update the velocity of the particle to avoid local minima and help particles to search global optimum with improved convergence. The performance of the newly developed algorithm is verified using various standard multimodal, multivariable, shifted hybrid composition benchmark problems. Further, the comparative analysis of HSPSO with variants of PSO is tested to control frequency of hybrid renewable energy system which comprises solar system, wind system, diesel generator, aqua electrolyzer and ultra capacitor. A significant improvement in convergence characteristic of HSPSO algorithm over other variants of PSO is observed in solving benchmark optimization and renewable hybrid system problems.

  14. A ground based phase control system for the solar power satellite, volume 4

    NASA Technical Reports Server (NTRS)

    Chie, C. M.

    1980-01-01

    A ground phase control system is studied as an alternative approach to the current reference retrodirective phase control system in order to simplify the spaceborne hardware requirement. Based on waveform selections, functional subsystems to implement the ground-based phase control concept are identified and functionally represented. It was concluded that the feasibility of the concept becomes unclear if the conditions of the ionosphere and satellite motion are not met.

  15. Test results on the Frenchman's Reef solar data acquisition and control system

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The Frenchman's Reef Data Acquisition and Control System (DACS), Sunlogger model 10000-1 was evaluated to determine the accuracy of control functions and the performance of the system in the environment of the planned installation site. The Sunlogger system was verified to perform normally in an environment of 100 F and approximately 90% humidity. It is recommended however that the Sunlogger be installed in a controlled environment with temperatures and humidity significantly lower than those referenced above.

  16. Optical control of multi-stage thin film solar cell production

    DOEpatents

    Li, Jian; Levi, Dean H.; Contreras, Miguel A.; Scharf, John

    2016-05-17

    Embodiments include methods of depositing and controlling the deposition of a film in multiple stages. The disclosed deposition and deposition control methods include the optical monitoring of a deposition matrix to determine a time when at least one transition point occurs. In certain embodiments, the transition point or transition points are a stoichiometry point. Methods may also include controlling the length of time in which material is deposited during a deposition stage or controlling the amount of the first, second or subsequent materials deposited during any deposition stage in response to a determination of the time when a selected transition point occurs.

  17. Solar and planetary oscillation control on climate change: a novel theory

    NASA Astrophysics Data System (ADS)

    Scafetta, N.

    2013-12-01

    I propose a theory of climate change that identifies patterns of natural variability and outperforms the anthropogenic global warming theory. Global surface temperature records (e.g. HadCRUT4) since 1850 are found to be characterized by climatic oscillations synchronous with specific solar, planetary and lunar harmonics superimposed on a background warming modulation. The latter is related to a long millennial solar oscillation and to changes in the chemical composition of the atmosphere (e.g. aerosol and greenhouse gases). By using also temperature, sea levels and solar proxy models throughout the Holocene, the main natural climatic oscillations appear to have periods of about 9.1, 10-11, 20-22, 60-62, ~115 and ~1000 years. However, current general circulation climate models, e.g. the CMIP5 GCMs, to be used in the AR5 IPCC Report in 2013, fail to reconstruct the observed climatic oscillations. The divergence between the data and the models predictions becomes particularly macroscopic after 2000 (the models have predicted an average warming of about 2 oC/century while the temperature did not rise) and during the last millennium (the models have predicted hockey-stick temperature patterns but fail to reconstruct the larger pre-industrial variability emerging from modern paleoclimatic temperature reconstructions). As an alternate, an empirical model is proposed that uses: (1) a specific set of decadal, multidecadal, secular and millennial astronomic harmonics to simulate the observed climatic oscillations; and (2) a 0.45 attenuation of the GCM ensemble mean simulations to model the anthropogenic and volcano forcing effects. The proposed empirical model outperforms the GCMs by better hindcasting the observed 1850-2012 climatic patterns. It is found that: (1) about 50-60% of the warming observed since 1850 and since 1970 was induced by natural oscillations likely resulting from harmonic astronomical forcings that are not yet included in the GCMs; (2) a 2000

  18. Examining System-Wide Impacts of Solar PV Control Systems with a Power Hardware-in-the-Loop Platform

    SciTech Connect

    Williams, Tess L.; Fuller, Jason C.; Schneider, Kevin P.; Palmintier, Bryan; Lundstrom, Blake; Chakraborty, Sudipta

    2014-06-08

    High penetration levels of distributed solar PV power generation can lead to adverse power quality impacts, such as excessive voltage rise, voltage flicker, and reactive power values that result in unacceptable voltage levels. Advanced inverter control schemes have been developed that have the potential to mitigate many power quality concerns. However, local closed-loop control may lead to unintended behavior in deployed systems as complex interactions can occur between numerous operating devices. To enable the study of the performance of advanced control schemes in a detailed distribution system environment, a test platform has been developed that integrates Power Hardware-in-the-Loop (PHIL) with concurrent time-series electric distribution system simulation. In the test platform, GridLAB-D, a distribution system simulation tool, runs a detailed simulation of a distribution feeder in real-time mode at the Pacific Northwest National Laboratory (PNNL) and supplies power system parameters at a point of common coupling. At the National Renewable Energy Laboratory (NREL), a hardware inverter interacts with grid and PV simulators emulating an operational distribution system. Power output from the inverters is measured and sent to PNNL to update the real-time distribution system simulation. The platform is described and initial test cases are presented. The platform is used to study the system-wide impacts and the interactions of inverter control modes—constant power factor and active Volt/VAr control—when integrated into a simulated IEEE 8500-node test feeder. We demonstrate that this platform is well-suited to the study of advanced inverter controls and their impacts on the power quality of a distribution feeder. Additionally, results are used to validate GridLAB-D simulations of advanced inverter controls.

  19. Energy-Efficient Control with Harvesting Predictions for Solar-Powered Wireless Sensor Networks.

    PubMed

    Zou, Tengyue; Lin, Shouying; Feng, Qijie; Chen, Yanlian

    2016-01-04

    Wireless sensor networks equipped with rechargeable batteries are useful for outdoor environmental monitoring. However, the severe energy constraints of the sensor nodes present major challenges for long-term applications. To achieve sustainability, solar cells can be used to acquire energy from the environment. Unfortunately, the energy supplied by the harvesting system is generally intermittent and considerably influenced by the weather. To improve the energy efficiency and extend the lifetime of the networks, we propose algorithms for harvested energy prediction using environmental shadow detection. Thus, the sensor nodes can adjust their scheduling plans accordingly to best suit their energy production and residual battery levels. Furthermore, we introduce clustering and routing selection methods to optimize the data transmission, and a Bayesian network is used for warning notifications of bottlenecks along the path. The entire system is implemented on a real-time Texas Instruments CC2530 embedded platform, and the experimental results indicate that these mechanisms sustain the networks' activities in an uninterrupted and efficient manner.

  20. Energy-Efficient Control with Harvesting Predictions for Solar-Powered Wireless Sensor Networks

    PubMed Central

    Zou, Tengyue; Lin, Shouying; Feng, Qijie; Chen, Yanlian

    2016-01-01

    Wireless sensor networks equipped with rechargeable batteries are useful for outdoor environmental monitoring. However, the severe energy constraints of the sensor nodes present major challenges for long-term applications. To achieve sustainability, solar cells can be used to acquire energy from the environment. Unfortunately, the energy supplied by the harvesting system is generally intermittent and considerably influenced by the weather. To improve the energy efficiency and extend the lifetime of the networks, we propose algorithms for harvested energy prediction using environmental shadow detection. Thus, the sensor nodes can adjust their scheduling plans accordingly to best suit their energy production and residual battery levels. Furthermore, we introduce clustering and routing selection methods to optimize the data transmission, and a Bayesian network is used for warning notifications of bottlenecks along the path. The entire system is implemented on a real-time Texas Instruments CC2530 embedded platform, and the experimental results indicate that these mechanisms sustain the networks’ activities in an uninterrupted and efficient manner. PMID:26742042

  1. Solar wind control of the open magnetosphere: Comparison of GGS/polar images and theory

    NASA Astrophysics Data System (ADS)

    Urquhart, Andrew Lee

    This investigation explores the connection between the open polar cap magnetic flux ΦPCF and interplanetary conditions. Φ PCF is determined from GGS/Polar VIS Earth Camera far ultraviolet observations of the aurora borealis. Observations from the GGS/Wind SWE and MFI instruments are used to characterize the interplanetary conditions. Additional observations from the IMP-8 PLA and MAG instruments are used to evaluate solar wind propagation time delay estimation methods so that the GGS/Wind observations can be better associated with the GGS/Polar observations. This allows the GGS/Wind observations to be used to estimate the polar cap potential φPCP values associated with the GGS/Polar ΦPCF values. Statistical methods are applied to determine a proxy relationship between φPCP and ΦPCF. The Rice Field Model (RFM) is modified to accept Φ PCF as a configuration parameter, and RFM polar caps are produced using Φ PCF determined both directly from the GGS/Polar images and by the proxy relationship from the GGS/Wind data. The RFM is able to produce polar caps with the same areas and open magnetic fluxes as the GGS/Polar observations, but the agreement in the polar cap shapes and locations leaves opportunities for further improvements.

  2. Guidance, navigation, and control study for a solar electric propulsion spacecraft

    NASA Technical Reports Server (NTRS)

    Kluever, Craig A.

    1995-01-01

    A preliminary investigation of a lunar-comet rendezvous mission using a solar electric propulsion (SEP) spacecraft was performed in two phases.The first phase involved exploration of the moon and the second involved rendezvous with a comet. The initial phase began with a chemical propulsion translunar injection and chemical insertion into a lunar orbit, followed by a low thrust SEP transfer to a circular, polar, low-lunar orbit. After collecting scientific data at the moon, the SEP spacecraft performed a spiral lunar escape maneuver to begin the interplanetary leg of the mission. After escape from the Earth-moon system, the SEP spacecraft maneuvered in interplanetary space and performed a rendezvous with a comet.The immediate goal of this study was to demonstrate the feasibility of using a low-thrust SEP spacecraft for orbit transfer to both the moon and a comet. Another primary goal was to develop a computer optimization code which would be robust enough to obtain minimum-fuel rendezvous trajectories for a wide range of comets.

  3. Controllable synthesis of hierarchical SnO2 microspheres for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Fen; Li, Xi-Fei; Li, De-Jun; Sun, Yuan-Wei; Zhang, Xian-Xi

    2015-04-01

    Three-dimensional hierarchical SnO2 microspheres were successfully synthesized through a rapid sonochemical reaction followed by a facile solvothermal process. The resultant samples were characterized in detail by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM). It was observed that the hierarchical SnO2 microspheres (∼2.2 μm) consist of nanoparticles (∼23-30 nm). These samples are used to fabricate photoelectrodes for dye-sensitized solar cells (DSSCs). The effects of different samples on the photovoltaic performance were studied based on photocurrent-voltage (J-V), intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated voltage spectroscopy (IMVS). It is found that the highest power conversion efficiency of 6.25% has been achieved based on the hierarchical SnO2 microspheres film photoanode with thickness of ∼13.5 μm, and the corresponding photovoltaic parameters are 14.11 mA cm-2 in short-circuit current density, 803 mV in open-circuit voltage and 0.55 in fill factor, respectively.

  4. Correlation between Hierarchical Structure and Processing Control of Large-area Spray-coated Polymer Solar Cells toward High Performance.

    PubMed

    Huang, Yu-Ching; Tsao, Cheng-Si; Cha, Hou-Chin; Chuang, Chih-Min; Su, Chun-Jen; Jeng, U-Ser; Chen, Charn-Ying

    2016-01-28

    The formation mechanism of a spray-coated film is different from that of a spin-coated film. This study employs grazing incidence small- and wide-angle X-ray Scattering (GISAXS and GIWAXS, respectively) quantitatively and systematically to investigate the hierarchical structure and phase-separated behavior of a spray-deposited blend film. The formation of PCBM clusters involves mutual interactions with both the P3HT crystal domains and droplet boundary. The processing control and the formed hierarchical structure of the active layer in the spray-coated polymer/fullerene blend film are compared to those in the spin-coated film. How the different post-treatments, such as thermal and solvent vapor annealing, tailor the hierarchical structure of the spray-coated films is quantitatively studied. Finally, the relationship between the processing control and tailored BHJ structures and the performance of polymer solar cell devices is established here, taking into account the evolution of the device area from 1 × 0.3 and 1 × 1 cm(2). The formation and control of the special networks formed by the PCBM cluster and P3HT crystallites, respectively, are related to the droplet boundary. These structures are favorable for the transverse transport of electrons and holes.

  5. Rantiga Osservatorio, Tincana (MPC-D03): Observations and searching for small Solar System bodies using a remotely controlled telescope

    NASA Astrophysics Data System (ADS)

    Zolnowski, M.; Kusiak, M.

    2014-07-01

    Rantiga Osservatorio is the first Polish project aimed at discovering and observing small solar-system objects, including near-Earth objects and comets. The observatory officially started in March 2012, as a result of cooperation between two amateur astronomers: Michal Zolnowski and Michal Kusiak. Subsequently, our station received official designation D03 assigned by the IAU's Minor Planet Center. The equipment is installed in northern Italy, on the border between Emilia-Romagna and Tuscany, in the small village of Tincana at an altitude of 643 m. The heart of the observatory is a 0.4-meter reflector f/3.8, mounted on Paramount ME and CCD camera SBIG STX-16803. The equipment is controlled by an industrial computer connected to the internet, and software allowing for automation and remote control of the telescope from Poland. It is also the first Polish amateur observatory which has been used for the discoveries of potentially new asteroids since 1949. Between 2012 and 2013, Rantiga Osservatorio made it possible to submit over 13,000 astrometric measurements of 3,500 asteroids, and we also reported 1,151 candidates for potentially unknown objects. During our presentation, we would like to introduce details of design and several enhancements to allow a convenient and safe way to control an observing session from anywhere in the world using a smartphone.

  6. Correlation between Hierarchical Structure and Processing Control of Large-area Spray-coated Polymer Solar Cells toward High Performance

    PubMed Central

    Huang, Yu-Ching; Tsao, Cheng-Si; Cha, Hou-Chin; Chuang, Chih-Min; Su, Chun-Jen; Jeng, U-Ser; Chen, Charn-Ying

    2016-01-01

    The formation mechanism of a spray-coated film is different from that of a spin-coated film. This study employs grazing incidence small- and wide-angle X-ray Scattering (GISAXS and GIWAXS, respectively) quantitatively and systematically to investigate the hierarchical structure and phase-separated behavior of a spray-deposited blend film. The formation of PCBM clusters involves mutual interactions with both the P3HT crystal domains and droplet boundary. The processing control and the formed hierarchical structure of the active layer in the spray-coated polymer/fullerene blend film are compared to those in the spin-coated film. How the different post-treatments, such as thermal and solvent vapor annealing, tailor the hierarchical structure of the spray-coated films is quantitatively studied. Finally, the relationship between the processing control and tailored BHJ structures and the performance of polymer solar cell devices is established here, taking into account the evolution of the device area from 1 × 0.3 and 1 × 1 cm2. The formation and control of the special networks formed by the PCBM cluster and P3HT crystallites, respectively, are related to the droplet boundary. These structures are favorable for the transverse transport of electrons and holes. PMID:26817585

  7. On quality control procedures for solar radiation and meteorological measures, from subhourly to montly average time periods

    NASA Astrophysics Data System (ADS)

    Espinar, B.; Blanc, P.; Wald, L.; Hoyer-Klick, C.; Schroedter-Homscheidt, M.; Wanderer, T.

    2012-04-01

    Meteorological data measured by ground stations are often a key element in the development and validation of methods exploiting satellite images. These data are considered as a reference against which satellite-derived estimates are compared. Long-term radiation and meteorological measurements are available from a large number of measuring stations. However, close examination of the data often reveals a lack of quality, often for extended periods of time. This lack of quality has been the reason, in many cases, of the rejection of large amount of available data. The quality data must be checked before their use in order to guarantee the inputs for the methods used in modelling, monitoring, forecast, etc. To control their quality, data should be submitted to several conditions or tests. After this checking, data that are not flagged by any of the test is released as a plausible data. In this work, it has been performed a bibliographical research of quality control tests for the common meteorological variables (ambient temperature, relative humidity and wind speed) and for the usual solar radiometrical variables (horizontal global and diffuse components of the solar radiation and the beam normal component). The different tests have been grouped according to the variable and the average time period (sub-hourly, hourly, daily and monthly averages). The quality test may be classified as follows: • Range checks: test that verify values are within a specific range. There are two types of range checks, those based on extrema and those based on rare observations. • Step check: test aimed at detecting unrealistic jumps or stagnation in the time series. • Consistency checks: test that verify the relationship between two or more time series. The gathered quality tests are applicable for all latitudes as they have not been optimized regionally nor seasonably with the aim of being generic. They have been applied to ground measurements in several geographic locations, what

  8. Homeostatic control: Economic integration of solar technologies into electric power operations and planning

    NASA Astrophysics Data System (ADS)

    Tabors, R. D.

    1981-07-01

    The economic issues associated with the interface of new energy technologies and the electric utility grid are discussed. The concept of homestatic control is introduced and the use of such an economic concept applied to the introduction of nondispatchable technologies into the existing utility system is examined. The transition and potential impact of a homeostatic control system working with the existing electric utility system is treated.

  9. Photovoltaic solar concentrator

    DOEpatents

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2016-03-15

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  10. Photovoltaic solar cell

    DOEpatents

    Nielson, Gregory N.; Gupta, Vipin P.; Okandan, Murat; Watts, Michael R.

    2015-09-08

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  11. Photovoltaic solar concentrator

    DOEpatents

    Nielson, Gregory N.; Okandan, Murat; Resnick, Paul J.; Cruz-Campa, Jose Luis

    2012-12-11

    A photovoltaic solar concentrator is disclosed with one or more transverse-junction solar cells (also termed point contact solar cells) and a lens located above each solar cell to concentrate sunlight onto the solar cell to generate electricity. Piezoelectric actuators tilt or translate each lens to track the sun using a feedback-control circuit which senses the electricity generated by one or more of the solar cells. The piezoelectric actuators can be coupled through a displacement-multiplier linkage to provide an increased range of movement of each lens. Each lens in the solar concentrator can be supported on a frame (also termed a tilt plate) having three legs, with the movement of the legs being controlled by the piezoelectric actuators.

  12. Advanced controls for stability assessment of solar dynamics space power generation

    NASA Astrophysics Data System (ADS)

    Momoh, James A.; Anwah, Nnamdi A.

    1995-08-01

    In support of the power requirements for the Space Station Alpha (SSA), a joint program by the U.S. and Russia for a permanently manned space station to be launched into orbit by 1998, a robust control scheme is needed to assure the stability of the rotating machines that will be integrated into the power subsystem. A framework design and systems studies for modeling and analysis is presented. It employs classical d-q axes machine model with voltage/frequency dependent loads. To guarantee that design requirements and necessary trade studies are done, a functional analysis tool CORE is used for the study. This provides us with different control options for stability assessment. Initial studies and recommendations using advanced simulation tools are also presented. The benefits of the stability/control scheme for evaluating future designs and power management are discussed.

  13. Advanced controls for stability assessment of solar dynamics space power generation

    NASA Technical Reports Server (NTRS)

    Momoh, James A.; Anwah, Nnamdi A.

    1995-01-01

    In support of the power requirements for the Space Station Alpha (SSA), a joint program by the U.S. and Russia for a permanently manned space station to be launched into orbit by 1998, a robust control scheme is needed to assure the stability of the rotating machines that will be integrated into the power subsystem. A framework design and systems studies for modeling and analysis is presented. It employs classical d-q axes machine model with voltage/frequency dependent loads. To guarantee that design requirements and necessary trade studies are done, a functional analysis tool CORE is used for the study. This provides us with different control options for stability assessment. Initial studies and recommendations using advanced simulation tools are also presented. The benefits of the stability/control scheme for evaluating future designs and power management are discussed.

  14. Solar radiation absorbing material

    DOEpatents

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  15. Microprocessor-based control of the photovoltaic solar power system for an AM radio station

    SciTech Connect

    Much, C. H.; Rothenheber, P. J.

    1980-01-01

    A microprocessor-based controller for a 15 kW photovoltaic power system powering an AM radio station keeps dc bus voltage between desired limits, governs battery operation, monitors safety conditions, and provides status reporting. The microprocessor also facilitates complicated algorithms that improve performance. The first three months of system operation are presented.

  16. Rigid Biopolymer Nanocrystal Systems for Controlling Multicomponent Nanoparticle Assembly and Orientation in Thin Film Solar Cells

    SciTech Connect

    Cha, Jennifer

    2016-10-31

    We have discovered techniques to synthesize well-defined DN conjugated nanostructures that are stable in a wide variety of conditions needed for DNA mediated assembly. Starting from this, we have shown that DNA can be used to control the assembly and integration of semiconductor nanocrystals into thin film devices that show photovoltaic effects.

  17. n-Type semiconducting naphthalene diimide-perylene diimide copolymers: controlling crystallinity, blend morphology, and compatibility toward high-performance all-polymer solar cells.

    PubMed

    Hwang, Ye-Jin; Earmme, Taeshik; Courtright, Brett A E; Eberle, Frank N; Jenekhe, Samson A

    2015-04-08

    Knowledge of the critical factors that determine compatibility, blend morphology, and performance of bulk heterojunction (BHJ) solar cells composed of an electron-accepting polymer and an electron-donating polymer remains limited. To test the idea that bulk crystallinity is such a critical factor, we have designed a series of new semiconducting naphthalene diimide (NDI)-selenophene/perylene diimide (PDI)-selenophene random copolymers, xPDI (10PDI, 30PDI, 50PDI), whose crystallinity varies with composition, and investigated them as electron acceptors in BHJ solar cells. Pairing of the reference crystalline (crystalline domain size Lc = 10.22 nm) NDI-selenophene copolymer (PNDIS-HD) with crystalline (Lc = 9.15 nm) benzodithiophene-thieno[3,4-b]thiophene copolymer (PBDTTT-CT) donor yields incompatible blends, whose BHJ solar cells have a power conversion efficiency (PCE) of 1.4%. However, pairing of the new 30PDI with optimal crystallinity (Lc = 5.11 nm) as acceptor with the same PBDTTT-CT donor yields compatible blends and all-polymer solar cells with enhanced performance (PCE = 6.3%, Jsc = 18.6 mA/cm(2), external quantum efficiency = 91%). These photovoltaic parameters observed in 30PDI:PBDTTT-CT devices are the best so far for all-polymer solar cells, while the short-circuit current (Jsc) and external quantum efficiency are even higher than reported values for [70]-fullerene:PBDTTT-CT solar cells. The morphology and bulk carrier mobilities of the polymer/polymer blends varied substantially with crystallinity of the acceptor polymer component and thus with the NDI/PDI copolymer composition. These results demonstrate that the crystallinity of a polymer component and thus compatibility, blend morphology, and efficiency of polymer/polymer blend solar cells can be controlled by molecular design.

  18. Control of the Earth's electric field intensity through solar wind modulation of galactic cosmic radiation: Support for a proposed atmospheric electrical sun-weather mechanism

    NASA Technical Reports Server (NTRS)

    Markson, R.

    1980-01-01

    The ionospheric potential and galactic cosmic radiation, found to be inversely correlated with the solar wind velocity are examined as being germane to weather modification. Since the ionospheric potential is proportional to the fair weather electric field intensity and cosmic radiation is the dominant source of atmospheric ionization, it is concluded that the Earth's overall electric field varies in phase with atmospheric ionization and that the latter is modulated by the solar wind. A proposed mechanism, in which solar control of ionizing radiation influences atmospheric electrification and thus possibly cloud physical processes is discussed. An experimental approach to critically test the proposed mechanism through comparison of the temporal variation of the Earth's electric field with conditions in the interplanetary medium is outlined.

  19. Modelling and control synthesis of a micro-combined heat and power interface for a concentrating solar power system in off-grid rural power applications

    NASA Astrophysics Data System (ADS)

    Prinsloo, Gerro; Dobson, Robert; Brent, Alan; Mammoli, Andrea

    2016-05-01

    Concentrating solar power co-generation systems have been identified as potential stand-alone solar energy supply solutions in remote rural energy applications. This study describes the modelling and synthesis of a combined heat and power Stirling CSP system in order to evaluate its potential performance in small off-grid rural village applications in Africa. This Stirling micro-Combined Heat and Power (micro-CHP) system has a 1 kW electric capacity, with 3 kW of thermal generation capacity which is produced as waste heat recovered from the solar power generation process. As part of the development of an intelligent microgrid control and distribution solution, the Trinum micro-CHP system and other co-generation systems are systematically being modelled on the TRNSYS simulation platform. This paper describes the modelling and simulation of the Trinum micro-CHP configuration on TRNSYS as part of the process to develop the control automation solution for the smart rural microgrid in which the Trinum will serve as a solar powerpack. The results present simulated performance outputs for the Trinum micro-CHP system for a number of remote rural locations in Africa computed from real-time TRNSYS solar irradiation and weather data (yearly, monthly, daily) for the relevant locations. The focus of this paper is on the parametric modelling of the Trinum Stirling micro-CHP system, with specific reference to this system as a TRNSYS functional block in the microgrid simulation. The model is used to forecast the solar energy harvesting potential of the Trinum micro-CHP unit at a number of remote rural sites in Africa.

  20. Design of a heat pipe governed thermal control system for the Solar Electric Propulsion Stage /SEPS/

    NASA Technical Reports Server (NTRS)

    Ruttner, L. E.; Wright, J. P.

    1975-01-01

    A 2200-w capacity spacecraft heat rejection system designed for the SEPS and utilizing heat pipe radiator panels has been investigated. The total thermal control system consists of two radiator panels connected to the heat source by variable conductance heat pipes (VCHP's). The system was designed to operate in the 223 to 333 temperature range. The radiators have an emittance of 0.88 at their operational temperature and a fin efficiency of approximately 80 percent. The radiators are thermally isolated from the SEPS and environment by multilayer insulation and thermal shields. Butane was selected as the working fluid for the VCHP because of its low freezing point (135), which is necessary to prevent diffusion freezeout of the liquid during the cold outbond missions. Helium was selected for the control gas. This paper describes the VCHP system, discusses the system design parameters and presents the results of the analyses.

  1. Microprocessor-based controller for automatic amorphous silicon solar cells characterization

    SciTech Connect

    Cibils, R.M.; Buitrago, R.H.

    1984-07-01

    This work describes an innovation of traditional systems used in C--V and G--V curve measurements. Although this system has been specifically developed to be used in the characterization of hydrogenated amorphous silicon (a-Si:H), it is useful when information about conductance (G) or capacitance (C) frequency dependence is needed. The highlights of the new system are signal heterodination and microprocessor-based digital control over current range and modulation frequency. The outstanding advantages of this system are significant reduction of operation time and more reliable measurements. Additionally, there is no waste of computer time in the control of data-acquisition operations. The system has an excellent signal-to-noise ratio, a nearly infinite line signal rejection, and a broad frequency range of operation (20 to 10/sup 5/ Hz).

  2. Aggregation and morphology control enables polymer solar cells with efficiencies near 11.5% (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Yan, He

    2015-10-01

    Current high-efficiency (>9.0%) PSCs are restricted to materials combinations that are based on limited donor polymers and only one specific fullerene acceptor, PC71BM. Furthermore, best-efficiency PSCs are mostly based on relatively thin (100 nm) active layers. Here we first report multiple cases of high-performance thick-film (300 nm) PSCs (efficiencies up to 10.8%, fill factors up to 77%) based on conventional PCBM and many non-PCBM fullerenes. Our simple aggregation control and materials design rules allowed us to develop, within a short time, three new donor polymer, six fullerenes (including C60-based fullerenes), and over ten polymer:fullerene combinations, all of which yielded higher efficiency than previous state of art devices (~9.5%). The common structural feature of the three new donor polymers, the 2-octyldodecyl (2OD) alkyl chains sitting on quaterthiophene, causes a temperature-dependent aggregation behavior that allows for the processing of the polymer solutions at moderately elevated temperature, and more importantly, controlled aggregation and strong crystallization of the polymer during the film cooling and drying process. This results in a well-controlled and near-ideal polymer:fullerene morphology (containing highly crystalline, preferentially orientated, yet small polymer domains) that is controlled by polymer aggregation during warm casting and thus insensitive to the choice of fullerenes. The 2OD structural motif is then further applied to several other polymer backbones and produces three additional polymers with efficiencies between 10-11.5%. Our best efficiency (11.5%) is achieved via the combination of new structural designs, interface and optical engineering and optimizations on the solvents and additives of the polymer:fullerene solution.

  3. Controlled Assembly of Hybrid Bulk-Heterojunction Solar Cells bySequential Deposition

    SciTech Connect

    Gur, Ilan; Fromer, Neil A.; Alivisatos, A. Paul

    2006-08-13

    This work presents a technique to create ordered and easily characterized hybrid nanocrystal-polymer composites by sequential deposition of tetrapod-shaped cadmium telluride (CdTe) nanocrystals and poly(3-hexlythiophene). With controlled fabrication and composite morphology, these devices offer several advantages over traditional codeposited hybrid cells, and provide a model system for detailed investigation into the operation of bulk-heterojunction cells.

  4. Fundamentals of Solar Heating. Correspondence Course.

    ERIC Educational Resources Information Center

    Sheet Metal and Air Conditioning Contractors National Association, Vienna, VA.

    This course is designed for the use of employees of the air conditioning industry, and offers supervised correspondence instruction about solar technology. The following aspects of applied solar technology are covered: solar heating and cooling, solar radiation, solar collectors, heat storage control devices and specialty items, sizing solar…

  5. Can the halophilic ciliate Fabrea salina be used as a bio-control of microalgae blooms in solar salterns?

    NASA Astrophysics Data System (ADS)

    Hong, Hyun Pyo; Choi, Joong Ki

    2015-09-01

    The microlage Dunaliella salina, a major producer in salterns, is a serious problem for salt production. In this study we tried to assess if Fabrea salina can control D. salina. By parameterising numerical and functional response (growth and grazing vs prey abundance, respectively) at 90 psu and 30°C, where the ciliate is abundant and grows well, we developed a predator-prey model. The model is used to explore how change in microalga growth rate affect the dynamics, and the functional response is used in combination with field data to assess the potential impact of F. salina on D. salina. Over the 20 d simulation the ciliate controlled the prey population under all prey growth rates; although once D. salina were exhausted below the threshold level, F. salina died due to starvation, allowing the alga to increase in abundance, resulting in one or two predatorprey cycle, depending on prey growth rate. In general, the model predicted trends observed by others in the field, suggesting that it provided a good prediction of what may occur under the conditions we examined. Likewise we show that the ciliate can have a high impact on microalgal populations in the field. Finally, a literature review indicated that F. salina could be a good competitor with other protozoa and metazoan in salterns, depending on salinity and temperature, which requires further study and attention. In summary, we encourage continued studies on this unique ciliate on solar salterns and suggest that it may be useful in the bio-control of micoalgae.

  6. Annual DOE Active Solar Heating and Cooling Contractors Review meeting

    NASA Astrophysics Data System (ADS)

    1981-09-01

    Ninety three project summaries dicussing the following aspects of active solar heating and cooling are presented: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology.

  7. Electric Fields Control TiO2(e(-)) + I3(-) → Charge Recombination in Dye-Sensitized Solar Cells.

    PubMed

    Sampaio, Renato N; O'Donnell, Ryan M; Barr, Timothy J; Meyer, Gerald J

    2014-09-18

    The electric fields generated by excited-state electron injection into anatase TiO2 nanocrystallites are screened by cations present in the external electrolyte. With some assumptions, a newly discovered electroabsorption signature enables quantification of the electric field strength experienced by surface-anchored dye molecules. Here, it was found that the fields increased in the order Na(+) < Li(+) < Mg(2+) < Ca(2+), with magnitudes of 1.1 MV/cm for Na(+) and 2.2 MV/cm for Ca(2+), values that were insensitive to whether the anion was iodide or perchlorate. The magnitude of the field was directly related to average TiO2(e(-)) + I3(-) → charge recombination rate constants abstracted from time-resolved kinetic data. Extrapolation to zero field provided an estimate of recombination dynamics when diffusion alone controlled I3(-) mass transport, k = 300 s(-1). The decreased rate constants measured after excited-state injection were attributed to migration of I3(-) away from the TiO2. Cation transference coefficients were tabulated that ranged from t = 0.97 for Ca(2+) to 0.40 for Na(+) and represented the ability of the unscreened electric field to block the TiO2(e(-)) + I3(-) → charge recombination reaction. This data provides the first compelling evidence that the anionic nature of I3(-) inhibits unwanted charge recombination in dye-sensitized solar cells.

  8. Stratospheric controlled perturbation experiment: a small-scale experiment to improve understanding of the risks of solar geoengineering.

    PubMed

    Dykema, John A; Keith, David W; Anderson, James G; Weisenstein, Debra

    2014-12-28

    Although solar radiation management (SRM) through stratospheric aerosol methods has the potential to mitigate impacts of climate change, our current knowledge of stratospheric processes suggests that these methods may entail significant risks. In addition to the risks associated with current knowledge, the possibility of 'unknown unknowns' exists that could significantly alter the risk assessment relative to our current understanding. While laboratory experimentation can improve the current state of knowledge and atmospheric models can assess large-scale climate response, they cannot capture possible unknown chemistry or represent the full range of interactive atmospheric chemical physics. Small-scale, in situ experimentation under well-regulated circumstances can begin to remove some of these uncertainties. This experiment-provisionally titled the stratospheric controlled perturbation experiment-is under development and will only proceed with transparent and predominantly governmental funding and independent risk assessment. We describe the scientific and technical foundation for performing, under external oversight, small-scale experiments to quantify the risks posed by SRM to activation of halogen species and subsequent erosion of stratospheric ozone. The paper's scope includes selection of the measurement platform, relevant aspects of stratospheric meteorology, operational considerations and instrument design and engineering.

  9. Dynamics of the Coupled Human-climate System Resulting from Closed-loop Control of Solar Geoengineering

    SciTech Connect

    MacMartin, Douglas; Kravitz, Benjamin S.; Keith, David; Jarvis, Andrew

    2014-07-08

    If solar radiation management (SRM) were ever implemented, feedback of the observed climate state might be used to adjust the radiative forcing of SRM, in order to compensate for uncertainty in either the forcing or the climate response; this would also compensate for unexpected changes in the system, e.g. a nonlinear change in climate sensitivity. This feedback creates an emergent coupled human-climate system, with entirely new dynamics. In addition to the intended response to greenhouse-gas induced changes, the use of feedback would also result in a geoengineering response to natural climate variability. We use a simple box-diffusion dynamic model to understand how changing feedback-control parameters and time delay affect the behavior of this coupled natural-human system, and verify these predictions using the HadCM3L general circulation model. In particular, some amplification of natural variability is unavoidable; any time delay (e.g., to average out natural variability, or due to decision-making) exacerbates this amplification, with oscillatory behavior possible if there is a desire for rapid correction (high feedback gain), but a delayed response needed for decision making. Conversely, the need for feedback to compensate for uncertainty, combined with a desire to avoid excessive amplification, results in a limit on how rapidly SRM could respond to uncertain changes.

  10. Solar wind density controlling penetration electric field at the equatorial ionosphere during a saturation of cross polar cap potential

    NASA Astrophysics Data System (ADS)

    Wei, Y.; Wan, W.; Zhao, B.; Hong, M.; Ridley, A.; Ren, Z.; Fraenz, M.; Dubinin, E.; He, M.

    2012-09-01

    The most important source of electrodynamic disturbances in the equatorial ionosphere during the main phase of a storm is the prompt penetration electric field (PPEF) originating from the high-latitude region. It has been known that such an electric field is correlated with the magnetospheric convection or interplanetary electric field. Here we show a unique case, in which the electric field disturbance in the equatorial ionosphere cannot be interpreted by this concept. During the superstorm on Nov. 20-21, 2003, the cross polar cap potential (CPCP) saturated at least for 8.2 h. The CPCP reconstructed by Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure suggested that the PPEF at the equatorial ionosphere still correlated with the saturated CPCP, but the CPCP was controlled by the solar wind density instead of the interplanetary electric field. However, the predicted CPCPs by Hill-Siscoe-Ober (HSO) model and Boyle-Ridley (BR) model were not fully consistent with the AMIE result and PPEF. The PPEF also decoupled from the convection electric field in the magnetotail. Due to the decoupling, the electric field in the ring current was not able to comply with the variations of PPEF, and this resulted in a long-duration electric field penetration without shielding.

  11. Size-controlled anatase titania single crystals with octahedron-like morphology for dye-sensitized solar cells.

    PubMed

    Shiu, Jia-Wei; Lan, Chi-Ming; Chang, Yu-Cheng; Wu, Hui-Ping; Huang, Wei-Kai; Diau, Eric Wei-Guang

    2012-12-21

    A simple hydrothermal method with titanium tetraisopropoxide (TTIP) as a precursor and triethanolamine (TEOA) as a chelating agent enabled growth in the presence of a base (diethylamine, DEA) of anatase titania nanocrystals (HD1-HD5) of controlled size. DEA played a key role to expedite this growth, for which a biphasic crystal growth mechanism is proposed. The produced single crystals of titania show octahedron-like morphology with sizes in a broad range of 30-400 nm; a typical, extra large, octahedral single crystal (HD5) of length 410 nm and width 260 nm was obtained after repeating a sequential hydrothermal treatment using HD3 and then HD4 as a seed crystal. The nanocrystals of size ~30 nm (HD1) and ~300 nm (HD5) served as active layer and scattering layer, respectively, to fabricate N719-sensitized solar cells. These HD devices showed greater V(OC) than devices of conventional nanoparticle (NP) type; the overall device performance of HD attained an efficiency of 10.2% power conversion at a total film thickness of 28 μm, which is superior to that of a NP-based reference device (η = 9.6%) optimized at a total film thickness of 18-20 μm. According to results obtained from transient photoelectric and charge extraction measurements, this superior performance of HD devices relative to their NP counterparts is due to the more rapid electron transport and greater TiO(2) potential.

  12. SOLERAS - Solar Controlled Environment Agriculture Project. Final report, Volume 9. Science Applications, Incorporated Phase 2 - definition study

    SciTech Connect

    Not Available

    1985-01-01

    This report describes the effort required to implement the design of the Solar Controlled Environment Agriculture Engineering Test Facility, SCEA-ETF. This report is a basic blueprint for the Phase 2 activities which have as a goal the construction of the ETF. These activities have been broken down into five major tasks, namely Project Management; Engineering and Design; Procurement/Fabrication; Construction, Installation and Checkout; and Operation and Maintenance. The type of activities required under each of these tasks are described followed by a detailed work breakdown structure. The Phase 2 project organization is discussed. A 13 month schedule for the total project is also given. Lastly, two appendices discuss cost adjustment factors for an ETF located in the KSA, and an update of the commercial system cost estimate based on preliminary cost quotations for the ETF. The results show a 63% cost increase for the KSA ETF primarily due to higher construction costs and greater well depth. The commercial system cost required an adjustment upwards of 7.7%.

  13. Dynamics of the coupled human-climate system resulting from closed-loop control of solar geoengineering

    NASA Astrophysics Data System (ADS)

    MacMartin, Douglas G.; Kravitz, Ben; Keith, David W.; Jarvis, Andrew

    2014-07-01

    If solar radiation management (SRM) were ever implemented, feedback of the observed climate state might be used to adjust the radiative forcing of SRM in order to compensate for uncertainty in either the forcing or the climate response. Feedback might also compensate for unexpected changes in the system, e.g. a nonlinear change in climate sensitivity. However, in addition to the intended response to greenhouse-gas induced changes, the use of feedback would also result in a geoengineering response to natural climate variability. We use a box-diffusion dynamic model of the climate system to understand how changing the properties of the feedback control affect the emergent dynamics of this coupled human-climate system, and evaluate these predictions using the HadCM3L general circulation model. In particular, some amplification of natural variability is unavoidable; any time delay (e.g., to average out natural variability, or due to decision-making) exacerbates this amplification, with oscillatory behavior possible if there is a desire for rapid correction (high feedback gain). This is a challenge for policy as a delayed response is needed for decision making. Conversely, the need for feedback to compensate for uncertainty, combined with a desire to avoid excessive amplification of natural variability, results in a limit on how rapidly SRM could respond to changes in the observed state of the climate system.

  14. Stratospheric controlled perturbation experiment: a small-scale experiment to improve understanding of the risks of solar geoengineering

    PubMed Central

    Dykema, John A.; Keith, David W.; Anderson, James G.; Weisenstein, Debra

    2014-01-01

    Although solar radiation management (SRM) through stratospheric aerosol methods has the potential to mitigate impacts of climate change, our current knowledge of stratospheric processes suggests that these methods may entail significant risks. In addition to the risks associated with current knowledge, the possibility of ‘unknown unknowns’ exists that could significantly alter the risk assessment relative to our current understanding. While laboratory experimentation can improve the current state of knowledge and atmospheric models can assess large-scale climate response, they cannot capture possible unknown chemistry or represent the full range of interactive atmospheric chemical physics. Small-scale, in situ experimentation under well-regulated circumstances can begin to remove some of these uncertainties. This experiment—provisionally titled the stratospheric controlled perturbation experiment—is under development and will only proceed with transparent and predominantly governmental funding and independent risk assessment. We describe the scientific and technical foundation for performing, under external oversight, small-scale experiments to quantify the risks posed by SRM to activation of halogen species and subsequent erosion of stratospheric ozone. The paper's scope includes selection of the measurement platform, relevant aspects of stratospheric meteorology, operational considerations and instrument design and engineering. PMID:25404681

  15. Controllable thin film crystal growth of a novel squaraine molecule in organic solar cells

    NASA Astrophysics Data System (ADS)

    Conrad, Brad; Spencer, Susan; Bougher, Cortney; Brown, Jesse; Kelley, Kyle; Heaphy, Patrick; Murcia, Victor; Gallivan, Cameron; Monfette, Amber; Andersen, John; Cody, Jeremy; Coffey, Tonya; Collison, Christopher

    2014-03-01

    We will discuss the formation, structures, and properties of squarine and squarine-PCBM blend thin-films using Atomic Force Microscopy, electrical characterization, UV-VIS-NIR, and Thin-film Xray Diffraction. Film properties are inferred from spectroscopic measurements and are correlated with crystallinity as determined by TFXRD and AFM. A comprehensive explanation of DiPSQ(OH)2 structures is provided and related to measured efficiencies up to 4.3. By controlling the blend ratio and other fabrication conditions, crystalline regions of higher mobility can be developed so as to make significant gains in power conversion efficiency, necessary to achieve long term goals for commercially viable NIR-active OPV devices. AppState Office of Student Research; Synthesis by Cody group. BRC thanks ORAU Junior Faculty Enhancement Award. SDS, CPG and AM thank DOE Award number DE-FG36-08GO88110. CJC and JAC thank NSF award number CBET-1236372.

  16. Low-boiling-point solvent additives can also enable morphological control in polymer solar cells

    SciTech Connect

    Mahadevapuram, Rakesh C.; Carr, John A.; Chen, Yuqing; Bose, Sayantan; Nalwa, Kanwar S.; Petrich, Jacob W.; Chaudhary, Sumit

    2013-11-02

    Processing organic photovoltaic (OPV) blend solutions with high-boiling-point solvent additives has recently been used for morphological control in bulk-heterojunction OPV cells. Here we show that even low-boiling-point solvents can be effective additives. When P3HT:PCBM OPV cells were processed with a low-boiling-point solvent tetrahydrafuran as an additive in parent solvent o-dichlorobenzene, charge extraction increased leading to fill factors as high as 69.5%, without low work-function cathodes, electrode buffer layers or thermal treatment. This was attributed to PCBM demixing from P3HT domains and better vertical phase separation, as indicated by photoluminescence lifetimes, hole mobilities, and shunt leakage currents. Dependence on solvent parameters and applicability beyond P3HT system was also investigated. (C) 2013 Elsevier B.V. All rights reserved.

  17. Dynamics and control of a continuum model for a solar power system

    NASA Technical Reports Server (NTRS)

    Juang, J. N.

    1980-01-01

    An approach for modeling dynamic equations of motion of a plate attached with rigid bodies is presented. The equations of motion are developed using the principle of virtual work. Lagrange multipliers are used as interaction forces and/or moments to maintain prescribed constraints which is the basis of the interconnection between the plate and rigid bodies. The overall approach is unique in the sense that a continuous model described by a family of partial differential equations is established. An approximate formulation by using variational method is established yielding a solution compatible with the assumed degree of approximation. The formulation is useful particularly when parametric study of dynamic response for a satellite power system is desired. As an example, an approximate governing equation of algebraic eigenvalue problem is given for a dual microwave power transmission system. Controller design is discussed.

  18. Solar Drinking Water Disinfection (SODIS) to Reduce Childhood Diarrhoea in Rural Bolivia: A Cluster-Randomized, Controlled Trial

    PubMed Central

    Mäusezahl, Daniel; Christen, Andri; Pacheco, Gonzalo Duran; Tellez, Fidel Alvarez; Iriarte, Mercedes; Zapata, Maria E.; Cevallos, Myriam; Hattendorf, Jan; Cattaneo, Monica Daigl; Arnold, Benjamin; Smith, Thomas A.; Colford, John M.

    2009-01-01

    Background Solar drinking water disinfection (SODIS) is a low-cost, point-of-use water purification method that has been disseminated globally. Laboratory studies suggest that SODIS is highly efficacious in inactivating waterborne pathogens. Previous field studies provided limited evidence for its effectiveness in reducing diarrhoea. Methods and Findings We conducted a cluster-randomized controlled trial in 22 rural communities in Bolivia to evaluate the effect of SODIS in reducing diarrhoea among children under the age of 5 y. A local nongovernmental organisation conducted a standardised interactive SODIS-promotion campaign in 11 communities targeting households, communities, and primary schools. Mothers completed a daily child health diary for 1 y. Within the intervention arm 225 households (376 children) were trained to expose water-filled polyethyleneteraphtalate bottles to sunlight. Eleven communities (200 households, 349 children) served as a control. We recorded 166,971 person-days of observation during the trial representing 79.9% and 78.9% of the total possible person-days of child observation in intervention and control arms, respectively. Mean compliance with SODIS was 32.1%. The reported incidence rate of gastrointestinal illness in children in the intervention arm was 3.6 compared to 4.3 episodes/year at risk in the control arm. The relative rate of diarrhoea adjusted for intracluster correlation was 0.81 (95% confidence interval 0.59–1.12). The median length of diarrhoea was 3 d in both groups. Conclusions Despite an extensive SODIS promotion campaign we found only moderate compliance with the intervention and no strong evidence for a substantive reduction in diarrhoea among children. These results suggest that there is a need for better evidence of how the well-established laboratory efficacy of this home-based water treatment method translates into field effectiveness under various cultural settings and intervention intensities. Further global

  19. Attitude Control Flight Experience: Coping with Solar Radiation and Ion Engines Leak Thrust in Hayabusa (MUSES-C)

    NASA Technical Reports Server (NTRS)

    Kawaguchi, Jun'ichiro; Kominato, Takashi; Shirakawa, Ken'ichi

    2007-01-01

    The paper presents the attitude reorientation taking the advantage of solar radiation pressure without use of any fuel aboard. The strategy had been adopted to make Hayabusa spacecraft keep pointed toward the Sun for several months, while spinning. The paper adds the above mentioned results reported in Sedona this February showing another challenge of combining ion engines propulsion tactically balanced with the solar radiation torque with no spin motion. The operation has been performed since this March for a half year successfully. The flight results are presented with the estimated solar array panel diffusion coefficient and the ion engine's swirl torque.

  20. From Fullerene-Polymer to All-Polymer Solar Cells: The Importance of Molecular Packing, Orientation, and Morphology Control.

    PubMed

    Kang, Hyunbum; Lee, Wonho; Oh, Jiho; Kim, Taesu; Lee, Changyeon; Kim, Bumjoon J

    2016-11-15

    All-polymer solar cells (all-PSCs), consisting of conjugated polymers as both electron donor (PD) and acceptor (PA), have recently attracted great attention. Remarkable progress has been achieved during the past few years, with power conversion efficiencies (PCEs) now approaching 8%. In this Account, we first discuss the major advantages of all-PSCs over fullerene-polymer solar cells (fullerene-PSCs): (i) high light absorption and chemical tunability of PA, which affords simultaneous enhancement of both the short-circuit current density (JSC) and the open-circuit voltage (VOC), and (ii) superior long-term stability (in particular, thermal and mechanical stability) of all-PSCs due to entangled long PA chains. In the second part of this Account, we discuss the device operation mechanism of all-PSCs and recognize the major challenges that need to be addressed in optimizing the performance of all-PSCs. The major difference between all-PSCs and fullerene-PSCs originates from the molecular structures and interactions, i.e., the electron transport ability in all-PSCs is significantly affected by the packing geometry of two-dimensional PA chains relative to the electrodes (e.g., face-on or edge-on orientation), whereas spherically shaped fullerene acceptors can facilitate isotropic electron transport properties in fullerene-PSCs. Moreover, the crystalline packing structures of PD and PA at the PD-PA interface greatly affect their free charge carrier generation efficiencies. The design of PA polymers (e.g., main backbone, side chain, and molecular weight) should therefore take account of optimizing three major aspects in all-PSCs: (1) the electron transport ability of PA, (2) the molecular packing structure and orientation of PA, and (3) the blend morphology. First, control of the backbone and side-chain structures, as well as the molecular weight, is critical for generating strong intermolecular assembly of PA and its network, thus enabling high electron transport ability

  1. Pioneering with Solar Power.

    ERIC Educational Resources Information Center

    Pollack, George; Pollack, Mary

    1982-01-01

    Describes the development of Mississippi County Community College's (MCCC's) solar energy system. Explains the functioning of the campus's computer-controlled photovoltaic concentrator system, MCCC's cooperative agreement with the Arkansas-Missouri Power Company, program funding, the integration of the solar system with other building components,…

  2. New Directions for Solar Energy

    ERIC Educational Resources Information Center

    Glaser, Peter E.; Burke, James C.

    1973-01-01

    Describes new applications being found for solar energy as a result of technical advances and a variety of economic and social forces. Discusses the basic requirements for a solar climate control system and outlines factors that should stimulate greater use of solar energy in the near future. (JR)

  3. Solar Water Heater Installation Package

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A 48-page report describes water-heating system, installation (covering collector orientation, mounting, plumbing and wiring), operating instructions and maintenance procedures. Commercial solar-powered water heater system consists of a solar collector, solar-heated-water tank, electrically heated water tank and controls. Analysis of possible hazards from pressure, electricity, toxicity, flammability, gas, hot water and steam are also included.

  4. The Alfven Mach Number Control of the Solar Wind-Magnetosphere Coupling Efficiency and the Saturation of the Geomagnetic Indices

    NASA Astrophysics Data System (ADS)

    Myllys, M. E.; Kilpua, E.; Lavraud, B.

    2015-12-01

    We have investigated the effect of key solar wind driving parameters on the solar wind-magnetosphere coupling efficiency and saturation of the cross polar cap potential (CPCP) during sheath and magnetic cloud driven storms. The particular focus of the study was on the coupling efficiency dependence with Alfven Mach number (MA).Since we are studying the instantaneous coupling efficiency instead of the average efficiency over the whole solar wind structure, we needed to take into account the communication time between the solar wind and the magnetosphere. We present the results of the time delay analysis between geomagnetic indices (PCN, AE and SYM-H) and the interplanetary electric field y-component (EY, GSM coordinate system) and Newell and Borovsky functions. The study shows that the MA has a clear effect to the saturation of the PCN index, which can be used as a proxy of the polar cap potential. The higher the MA the higher the limit EY value after which the saturation starts to occur. Thus, the coupling efficiency increases as a function of MA. Also, the AE index saturates during high solar wind driving but the saturation is not MA depended. However, the results also suggest that the MA it is not the primary cause for the PCN saturation.

  5. Solar Sails

    NASA Technical Reports Server (NTRS)

    Young, Roy

    2006-01-01

    The Solar Sail Propulsion investment area has been one of the three highest priorities within the In-Space Propulsion Technology (ISPT) Project. In the fall of 2003, the NASA Headquarters' Science Mission Directorate provided funding and direction to mature the technology as far as possible through ground research and development from TRL 3 to 6 in three years. A group of experts from government, industry, and academia convened in Huntsville, Alabama to define technology gaps between what was needed for science missions to the inner solar system and the current state of the art in ultra1ightweight materials and gossamer structure design. This activity set the roadmap for development. The centerpiece of the development would be the ground demonstration of scalable solar sail systems including masts, sails, deployment mechanisms, and attitude control hardware and software. In addition, new materials would be subjected to anticipated space environments to quantify effects and assure mission life. Also, because solar sails are huge structures, and it is not feasible to validate the technology by ground test at full scale, a multi-discipline effort was established to develop highly reliable analytical models to serve as mission assurance evidence in future flight program decision-making. Two separate contractor teams were chosen to develop the SSP System Ground Demonstrator (SGD). After a three month conceptual mission/system design phase, the teams developed a ten meter diameter pathfinder set of hardware and subjected it to thermal vacuum tests to compare analytically predicted structural behavior with measured characteristics. This process developed manufacturing and handling techniques and refined the basic design. In 2005, both contractor teams delivered 20 meter, four quadrant sail systems to the largest thermal vacuum chamber in the world in Plum Brook, Ohio, and repeated the tests. Also demonstrated was the deployment and articulation of attitude control

  6. Controlling adverse and beneficial effects of solar UV radiation by wearing suitable clothes - spectral transmission of different kinds of fabrics.

    PubMed

    Sobolewski, Piotr S; Krzyścin, Janusz W; Jarosławski, Janusz; Wink, Jakub; Lesiak, Aleksandra; Narbutt, Joanna

    2014-11-01

    Humans should avoid prolonged exposure to the Sun during the warm subperiod of the year with naturally high solar UV level. One of the known recommendations to avoid excessive UV radiation is wearing clothes with UV protection additives. However there is an important question: how do we get an adequate solar UV radiation, which maintains a healthy status of vitamin D, without facing overexposure risks? It is found that some kind of 100% cotton knitted fabric, used in the production of normal daily clothing, has ∼15% transmittance of solar UV. Model studies show that a garment made of this fabric allows larger synthesis of vitamin D3 in human body without the erythema risks (skin redness). Thus the adequate level of vitamin D could be attained safely by a person exposing only small part of the body (face, palms) during the period (May-August) of the year.

  7. Controlling the texture and crystallinity of evaporated lead phthalocyanine thin films for near-infrared sensitive solar cells.

    PubMed

    Vasseur, Karolien; Broch, Katharina; Ayzner, Alexander L; Rand, Barry P; Cheyns, David; Frank, Christian; Schreiber, Frank; Toney, Michael F; Froyen, Ludo; Heremans, Paul

    2013-09-11

    To achieve organic solar cells with a broadened spectral absorption, we aim to promote the growth of the near-infrared (NIR)-active polymorph of lead phthalocyanine (PbPc) on a relevant electrode for solar cell applications. We studied the effect of different substrate modification layers on PbPc thin film structure as a function of thickness and deposition rate (rdep). We characterized crystallinity and orientation by grazing incidence X-ray diffraction (GIXD) and in situ X-ray reflectivity (XRR) and correlated these data to the performance of bilayer solar cells. When deposited onto a self-assembled monolayer (SAM) or a molybdenum oxide (MoO3) buffer layer, the crystallinity of the PbPc films improves with thickness. The transition from a partially crystalline layer close to the substrate to a more crystalline film with a higher content of the NIR-active phase is enhanced at low rdep, thereby leading to solar cells that exhibit a higher maximum in short circuit current density (JSC) for thinner donor layers. The insertion of a CuI layer induces the formation of strongly textured, crystalline PbPc layers with a vertically homogeneous structure. Solar cells based on these templated donor layers show a variation of JSC with thickness that is independent of rdep. Consequently, without decreasing rdep we could achieve JSC=10 mA/cm2, yielding a bilayer solar cell with a peak external quantum efficiency (EQE) of 35% at 900 nm, and an overall power conversion efficiency (PCE) of 2.9%.

  8. Solar Generator

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The Vanguard I dish-Stirling module program, initiated in 1982, produced the Vanguard I module, a commercial prototype erected by the Advanco Corporation. The module, which automatically tracks the sun, combines JPL mirrored concentrator technology, an advanced Stirling Solar II engine/generator, a low cost microprocessor-controlled parabolic dish. Vanguard I has a 28% sunlight to electricity conversion efficiency. If tests continue to prove the system effective, Advanco will construct a generating plant to sell electricity to local utilities. An agreement has also been signed with McDonnell Douglas to manufacture a similar module.

  9. Solar dynamic modules for Space Station Freedom: The relationship between fine-pointing control and thermal loading of the aperture plate

    NASA Technical Reports Server (NTRS)

    Quinn, Roger D.; Kerslake, Thomas W.

    1992-01-01

    Dynamic simulations of Space Station Freedom (SSF) configured with solar dynamic (SD) power modules were performed. The structure was subjected to Space Shuttle docking disturbances, while being controlled with a 'natural' vibration and tracking control approach. Three control cases were investigated for the purpose of investigating the relationship between actuator effort, SD pointing, and thermal loading on the receiver aperture plate. Transient, one-dimensional heat transfer analyses were performed to conservatively predict temperatures of the multi-layered receiver aperture plate assembly and thermal stresses in its shield layer. Results indicate that the proposed aperture plate is tolerant of concentrated flux impingement during short-lived structural disturbances. Pointing requirements may be loosened and the requirement control torques lessened from that previously specified. Downsizing and simplifying the joint drive system should result in a considerable savings mass.

  10. Improved performance by morphology control via fullerenes in PBDT-TBT-alkoBT based organic solar cells

    SciTech Connect

    Khatiwada, Devendra; Venkatesan, Swaminathan; Chen, QIliang; Chen, Jihua; Adhikari, Nirmal; Dubey, Ashish; Mitul, Abu Farzan; Mohammed, Lal; Qiao, Qiquan

    2015-01-01

    In this work, we report improved performance by controlling morphology using different fullerene derivatives in poly{2-octyldodecyloxy-benzo[1,2-b;3,4-b]dithiophene-alt-5,6-bis(dodecyloxy)-4,7- di(thieno[3,2-b]thiophen-2-yl)-benzo[c][1,2,5]thiadiazole} (PBDT-TBT-alkoBT) based organic solar cells. PC60BM and PC70BM fullerenes were used to investigate the characteristic change in morphology and device performance. Fullerene affects device efficiency by changing active layer morphology. PC70BM with broader absorption than PC60BM resulted in reduced device performance which was elucidated by the intermixed granular morphology separating each larger grain in the PC70BM/polymer composite layer which created higher density of traps. However after adding additive 1,8-diiodooctane (DIO), the fibrous morphology was observed due to reduced solubility of polymer and increased solubility of PC70BM in chloroform. The fibrous morphology improved charge transport leading to increase in overall device performance. Atomic force microscopies (AFM), photo induced charge extraction by linearly increasing voltage (photo-CELIV), and Kelvin prove force microscope (KPFM) were used to investigate nanoscale morphology of active layer with different fullerene derivatives. For PC60BM based active layer, AFM images revealed dense fibrous morphology and more distinct fibrous morphology was observed by adding DIO. The PC70BM based active layer only exhibited intermixed granular morphology instead of fibrous morphology observed in PC60BM based active layer. However, addition of DIO in PC70BM based active layer led to fibrous morphology. When additive DIO was not used, a wider distribution of surface potential was observed for PC70BM than PC60BM based active layer by KPFM measurements, indicating 2 polymer and fullerene domains are separated. When DIO was used, narrower distribution of surface potential for both PC70

  11. Improved performance by morphology control via fullerenes in PBDT-TBT-alkoBT based organic solar cells

    DOE PAGES

    Khatiwada, Devendra; Venkatesan, Swaminathan; Chen, QIliang; ...

    2015-01-01

    In this work, we report improved performance by controlling morphology using different fullerene derivatives in poly{2-octyldodecyloxy-benzo[1,2-b;3,4-b]dithiophene-alt-5,6-bis(dodecyloxy)-4,7- di(thieno[3,2-b]thiophen-2-yl)-benzo[c][1,2,5]thiadiazole} (PBDT-TBT-alkoBT) based organic solar cells. PC60BM and PC70BM fullerenes were used to investigate the characteristic change in morphology and device performance. Fullerene affects device efficiency by changing active layer morphology. PC70BM with broader absorption than PC60BM resulted in reduced device performance which was elucidated by the intermixed granular morphology separating each larger grain in the PC70BM/polymer composite layer which created higher density of traps. However after adding additive 1,8-diiodooctane (DIO), the fibrous morphology was observed due to reduced solubility of polymer and increasedmore » solubility of PC70BM in chloroform. The fibrous morphology improved charge transport leading to increase in overall device performance. Atomic force microscopies (AFM), photo induced charge extraction by linearly increasing voltage (photo-CELIV), and Kelvin prove force microscope (KPFM) were used to investigate nanoscale morphology of active layer with different fullerene derivatives. For PC60BM based active layer, AFM images revealed dense fibrous morphology and more distinct fibrous morphology was observed by adding DIO. The PC70BM based active layer only exhibited intermixed granular morphology instead of fibrous morphology observed in PC60BM based active layer. However, addition of DIO in PC70BM based active layer led to fibrous morphology. When additive DIO was not used, a wider distribution of surface potential was observed for PC70BM than PC60BM based active layer by KPFM measurements, indicating 2 polymer and fullerene domains are separated. When DIO was used, narrower distribution of surface potential for both PC70BM and PC60BM based active layers was observed. Photo-CELIV experiment

  12. Mechanism and control of the structural evolution of a polymer solar cell from a bulk heterojunction to a thermally unstable hierarchical structure.

    PubMed

    Chen, Charn-Ying; Tsao, Cheng-Si; Huang, Yu-Ching; Liu, Hung-Wei; Chiu, Wen-Yen; Chuang, Chih-Min; Jeng, U-Ser; Su, Chun-Jen; Wu, Wei-Ru; Su, Wei-Fang; Wang, Leeyih

    2013-08-21

    We simultaneously employed grazing incidence small-angle and wide-angle X-ray scattering (GISAXS and GIWAXS) techniques to quantitatively study the structural evolution and kinetic behavior of poly(3-hexylthiophene) (P3HT) crystallization, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) aggregation and amorphous P3HT/PCBM domains from a bulk heterojunction (BHJ) to a thermally unstable structure. The independent phase separation regimes on the nanoscale (∼10 nm), mesoscale (∼100 nm) and macroscale (∼μm) are revealed for the first time. Bis-PCBM molecules as inhibitors incorporated into the P3HT/PCBM blend films were adopted as a case study of a control strategy for improving the thermal stability of P3HT/PCBM solar cell. The detailed information on the formation, growth, transformation and mutual interaction between different phases during the hierarchical structural evolution of P3HT/PCBM:xbis-PCBM (x = 8-100%) blend films are presented herein. This systematic study proposes the mechanisms of thermal instability for a polymer/fullerene-based solar cell. We demonstrate a new fundamental concept that the structural evolution and thermal stability of mesoscale amorphous P3HT/PCBM domains during heating are the origin of controlling thermal instability rather than those of nanoscale thermally-stable BHJ structures. It leads to a low-cost and easy-fabrication control strategy for effectively tailoring the hierarchical morphology against thermal instability from molecular to macro scales. The optimum treatment achieving high thermal stability, control of mesoscale domains, can be effectively designed. It is independent of the original BHJ nanostructure design of a polymer/fullerene-based solar cell with high performance. It advances the general knowledge on the thermal instability directly arising from the nanoscale structure.

  13. Solar Energy.

    ERIC Educational Resources Information Center

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  14. Solar energy

    NASA Technical Reports Server (NTRS)

    Rapp, D.

    1981-01-01

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  15. Solar or meteorological control of lower ionospheric fluctuations (2-15 and 27 days) in middle latitudes

    NASA Technical Reports Server (NTRS)

    Pancheva, D.; Lastovicka, Jan

    1989-01-01

    Several types of short and long term effects of solar activity on the lower ionosphere are related to solar flares, the sector structure of the interplanetary magnetic field and some periodicities in sunspots or solar radio flux. The most evident periodicities of the Sun are the 11 year cycle of its activity and the differential rotation period near 27 days (25 to 30 days). Here, the following questions are discussed: which periods between 2 and 15 days and near 27 days occur in ionospheric absorption during the interval July 1980 to July 1985 and are these periods related to similar periods in solar Ly-alpha flux, geomagnetic activity, or neutral wind near 95 km observed in Collm (GDR). Day-time absorption data obtained by the A3 method was used for the following radio-paths: (164 kHz), (1539 kHz), (6090 kHz). With the use of these data the electron density variations in the lower ionosphere can be analyzed. An attempt was made to clarify the nature of the observed fluctuations in absorption.

  16. Effect of Morphology Control of Light Absorbing Layer on CH3NH3PbI3 Perovskite Solar Cells.

    PubMed

    Lei, Binglong; Eze, Vincent Obiozo; Mori, Tatsuo

    2016-04-01

    As one of the most significant components of perovskite solar cells, the perovskite light absorbing layer demands high quality to guarantee extraordinary power conversion efficiency (PCE). We have fabricated series of CH3NH3PbI3 perovskite solar cells by virtue of gas-flowing assisting (GFA), spin coating twice for the Pbl2 layer and dipping the semi-samples in a thermal CH3NH3I solution, by which some undesirable perovskite morphologies can be effectively avoided. The modified conductions have also dramatically improved the perovskite layer and elevated the coverage ratio from 53.6% to 79.5%. All the fabrication processes, except the steps for deposition of the hole transport material (HTM) and back gold electrode, have been conducted in air and an average PCE of 6.6% has been achieved by initiatively applying N,N'-bis(1-naphtyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (α-NPD) doped by MoO3 as HTM. The CH3NH3PbI3 perovskite's morphology and its coverage ratio to the underneath TiO2 mesoporic layer are evaluated to account for the cells' performance. It has demonstrated that higher homogeneity and coverage ratio of the CH3NH3PbI3 layer have most significantly contributed to the solar cells' light conversion efficiency. Keywords: Perovskite, Solar Cell, Morphology, Coverage Ratio, Hole Transport Material.

  17. Influence of para substituents in controlling photophysical behavior and different non-covalent weak interactions in zinc complexes of a phenol based "end-off" compartmental ligand.

    PubMed

    Chakraborty, Prateeti; Adhikary, Jaydeep; Samanta, Sugata; Majumder, Ishani; Massera, Chiara; Escudero, Daniel; Ghosh, Sanjib; Bauza, Antonio; Frontera, Antonio; Das, Debasis

    2015-12-14

    Three dinuclear zinc(II) complexes with "end-off" compartmental ligands, namely 2,6-bis(N-ethylmorpholine-iminomethyl)-4-R-phenol (R = -CH3, Cl, (t)Bu) have been synthesized with the aim of exploring the role of the para substituent present in the ligand backbone in controlling the structural diversity, photophysical properties and different weak interactions of the complexes. All three species, with the general formula {2[Zn2L(CH3COO)2][Zn(NCS)4]}, show the complex anion Zn(NCS)4(2-) as a common structural feature decisive for crystallization. Interestingly, all of them possess several non-covalent weak interactions where the nature of the "R" group plays an essential role as exposed by DFT study. Besides exhibiting fluorescence behavior, the complexes also show para substitution controlled phosphorescence both at room and low temperature. Anisotropy studies suggest the existence of complexes 2 and 3 as dimers in solution. The origins of the unusual room temperature phosphorescence and fluorescence behavior of the complexes have been rationalized in the light of theoretical calculations.

  18. Solar Systems

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The solar collectors shown are elements of domestic solar hot water systems produced by Solar One Ltd., Virginia Beach, Virginia. Design of these systems benefited from technical expertise provided Solar One by NASA's Langley Research Center. The company obtained a NASA technical support package describing the d e sign and operation of solar heating equipment in NASA's Tech House, a demonstration project in which aerospace and commercial building technology are combined in an energy- efficient home. Solar One received further assistance through personal contact with Langley solar experts. The company reports that the technical information provided by NASA influenced Solar One's panel design, its selection of a long-life panel coating which increases solar collection efficiency, and the method adopted for protecting solar collectors from freezing conditions.

  19. Crystallization of a perovskite film for higher performance solar cells by controlling water concentration in methyl ammonium iodide precursor solution

    NASA Astrophysics Data System (ADS)

    Adhikari, Nirmal; Dubey, Ashish; Gaml, Eman A.; Vaagensmith, Bjorn; Reza, Khan Mamun; Mabrouk, Sally Adel Abdelsalam; Gu, Shaopeng; Zai, Jiantao; Qian, Xuefeng; Qiao, Qiquan

    2016-01-01

    An optimal small amount of water added into methyl ammonium iodide (MAI) solution in isopropyl alcohol (IPA) helps perovskite crystallization and leads to larger grain size from sequential deposition of perovskite films. The concentration of water was varied from 1% to 7% (vol% of IPA) in MAI solution and optical absorption, crystallization, morphology of perovskite films and their photovoltaic performance were studied in perovskite solar cells. 5% by volume was found to lead to preferential crystallization in the (110) plane with grain size about three times that of perovskite films prepared without adding water into the MAI solution. The optimal water concentration of 5% by volume in the MAI solution led to average perovskite grain size of ~600 nm and solar cell efficiency of 12.42% at forward scan with a rate of 0.5 V s-1. Device performance decreases after increasing water concentration beyond 5% in the MAI solution due to formation of the PbI2 phase. Transient photocurrent and photovoltage measurements show the shortest charge transport time at 0.99 μs and the longest charge carrier life time at 13.6 μs for perovskite films prepared from 5% water in MAI solution, which improved perovskite solar cell efficiency from 9.04% to 12.42%.An optimal small amount of water added into methyl ammonium iodide (MAI) solution in isopropyl alcohol (IPA) helps perovskite crystallization and leads to larger grain size from sequential deposition of perovskite films. The concentration of water was varied from 1% to 7% (vol% of IPA) in MAI solution and optical absorption, crystallization, morphology of perovskite films and their photovoltaic performance were studied in perovskite solar cells. 5% by volume was found to lead to preferential crystallization in the (110) plane with grain size about three times that of perovskite films prepared without adding water into the MAI solution. The optimal water concentration of 5% by volume in the MAI solution led to average perovskite

  20. Nanostructure control of graphene-composited TiO2 by a one-step solvothermal approach for high performance dye-sensitized solar cells.

    PubMed

    He, Ziming; Guai, Guanhong; Liu, Jing; Guo, Chunxian; Loo, Joachim Say Chye; Li, Chang Ming; Tan, Timothy Thatt Yang

    2011-11-01

    We present a one-step solvothermal approach to prepare uniform graphene-TiO(2) nanocomposites with delicately controlled TiO(2) nanostructures, including ultra-small 2 nm nanoparticles, 12 nm nanoparticles and nanorods. Using three composites as photoanode materials, the effect of nanostructure of graphene-composited TiO(2) on the performance of dye-sensitized solar cells was investigated, and results showed that the ultra-small 2 nm TiO(2)-graphene composite based photoanode exhibited the highest power conversion efficiency of 7.25%.

  1. Light-scattering properties of a woven shade-screen material used for daylighting and solar heat-gain control

    NASA Astrophysics Data System (ADS)

    Jonsson, Jacob C.; Lee, Eleanor S.; Rubin, Mike

    2008-08-01

    Shade-screens are widely used in commercial buildings as a way to limit the amount of direct sunlight that can disturb people in the building. The shade screens also reduce the solar heat-gain through glazing the system. Modern energy and daylighting analysis software such as EnergyPlus and Radiance require complete scattering properties of the scattering materials in the system. In this paper a shade screen used in the LBNL daylighting testbed is characterized using a photogoniometer and a normal angle of incidence integrating sphere. The data is used to create a complete bi-directional scattering distribution function (BSDF) that can be used in simulation programs. The resulting BSDF is compared to a model BSDFs, both directly and by calculating the solar heat-gain coefficient for a dual pane system using Window 6.

  2. Light-scattering properties of a woven shade-screen material used for daylighting and solar heat-gain control

    SciTech Connect

    Jonsson, Jacob; Jonsson, Jacob C.; Lee, Eleanor S.; Rubin, Mike

    2008-08-01

    Shade-screens are widely used in commercial buildings as a way to limit the amount of direct sunlight that can disturb people in the building. The shade screens also reduce the solar heat-gain through glazing the system. Modern energy and daylighting analysis software such as EnergyPlus and Radiance require complete scattering properties of the scattering materials in the system. In this paper a shade screen used in the LBNL daylighting testbed is characterized using a photogoniometer and a normal angle of incidence integrating sphere. The data is used to create a complete bi-directional scattering distribution function (BSDF) that can be used in simulation programs. The resulting BSDF is compared to a model BADFs, both directly and by calculating the solar heat-gain coefficient for a dual pane system using Window 6.

  3. Molecular control of quantum-dot internal electric field and its application to CdSe-based solar cells

    NASA Astrophysics Data System (ADS)

    Yaacobi-Gross, Nir; Soreni-Harari, Michal; Zimin, Marina; Kababya, Shifi; Schmidt, Asher; Tessler, Nir

    2011-12-01

    Inorganic nanocrystals are attractive materials for solar-cell applications. However, the performance of such devices is often limited by an insufficient alignment of energy levels in the nanocrystals. Here, we report that by attaching two different molecules to a single quantum dot or nanocrystal one can induce electric fields large enough to significantly alter the electronic and optoelectronic properties of the quantum dot. This electric field is created within the nanocrystals owing to a mixture of amine- and thiol-anchor-group ligands. Examining the steady state as well as temporal evolution of the optical properties and the nuclear magnetic resonances of the nanocrystals we found that the first excitonic peak shifts as a function of the capping-layer composition. We also demonstrate that the use of a mixed-ligand-induced electric field markedly enhances the charge generation efficiency in layer-by-layer CdSe-nanocrystal-based solar cells, thus improving the overall cell efficiency.

  4. An 18.2%-efficient black-silicon solar cell achieved through control of carrier recombination in nanostructures.

    PubMed

    Oh, Jihun; Yuan, Hao-Chih; Branz, Howard M

    2012-11-01

    Silicon nanowire and nanopore arrays promise to reduce manufacturing costs and increase the power conversion efficiency of photovoltaic devices. So far, however, photovoltaic cells based on nanostructured silicon exhibit lower power conversion efficiencies than conventional cells due to the enhanced photocarrier recombination associated with the nanostructures. Here, we identify and separately measure surface recombination and Auger recombination in wafer-based nanostructured silicon solar cells. By identifying the regimes of junction doping concentration in which each mechanism dominates, we were able to design and fabricate an independently confirmed 18.2%-efficient nanostructured 'black-silicon' cell that does not need the antireflection coating layer(s) normally required to reach a comparable performance level. Our results suggest design rules for efficient high-surface-area solar cells with nano- and microstructured semiconductor absorbers.

  5. The solar optical telescope

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Objectives of the Solar Optical Telescope are to study the physics of the Sun on the scale at which many of the important physical processes occur and to attain a resolution of 73km on the Sun or 0.1 arc seconds of angular resolution. Topics discussed in this overview of the Solar Optical Telescope include: why is the Solar Optical Telescope needed; current picture of the Sun's atmosphere and convection zone; scientific problems for the Solar Optical Telescope; a description of the telescope; the facility - science management, contamination control, and accessibility to the instruments; the scientific instruments - a coordinated instrument package for unlocking the Sun's secrets; parameters of the coordinated instrument package; science operations from the Space Shuttle; and the dynamic solar atmosphere.

  6. Control of dark current in photoelectrochemical (TiO2/I--I3-)) and dye-sensitized solar cells.

    PubMed

    Ito, Seigo; Liska, Paul; Comte, Pascal; Charvet, Raphaël; Péchy, Peter; Bach, Udo; Schmidt-Mende, Lukas; Zakeeruddin, Shaik Mohammed; Kay, Andreas; Nazeeruddin, Mohammad K; Grätzel, Michael

    2005-09-14

    The ruthenium complex bis-tetrabutylammonium cis-dithiocyanato-N,N'-bis-2,2'-bipyridine-4-carboxylic acid, 4'-carboxylate ruthenium(II), N-719, was found to block the dark current of dye sensitized solar cells (DSC), based on mesoporous TiO2 films deposited on a F-doped tin oxide electrode and the effect was compared to surface treatment by TiCl4 and the introduction of a compact TiO2 blocking layer.

  7. Facile control of intra- and inter-particle porosity in template-free synthesis of size-controlled nanoporous titanium dioxides beads for efficient organic-inorganic heterojunction solar cells

    NASA Astrophysics Data System (ADS)

    Veerappan, Ganapathy; Yu, Sora; Wang, Dong Hwan; Lee, Wan In; Park, Jong Hyeok

    2015-04-01

    In thin film solid-state heterojunction solar cells (HSCs), titanium-dioxide (TiO2) electrodes need to be optimized to have large specific surface area, controllable pore sizes, and superior light scattering properties. In this study, we synthesize hierarchical nanoporous TiO2 beads with sub-micron diameters by a template-free, fast, and low-temperature synthetic scheme to satisfy the aforementioned requirements for HSCs. These nanoporous TiO2 beads are composed of numerous TiO2 nano crystallites that provide mesopores, and the inter-particle distances of size-controlled TiO2 beads can provide additional controllable macropores. We report the first successful application of TiO2 bead films (SP250, SP450) with controllable hierarchical nanostructure to be sensitized with Sb2S3 for all-solid-state heterojunction solar cells (Sb-HSCs). The Sb-HSCs made using the controlled TiO2 beads as photoanodes exhibit a superior light-to electricity conversion efficiency of 4.8%, yielding more than 15% enhancement in comparison with that (3.6%) of commercial TiO2 nanoparticle (NP40) electrodes. The well-tailored photoanode with high surface area, fewer grain boundaries, multi-scale pore structure, and enhanced optical scattering results in much better infiltration of hole-conducting materials, decreased recombination with increased electron lifetime, and enhanced light scattering, which result in the enhanced photovoltaic properties.

  8. Highly Efficient Copper-Indium-Selenide Quantum Dot Solar Cells: Suppression of Carrier Recombination by Controlled ZnS Overlayers.

    PubMed

    Kim, Jae-Yup; Yang, Jiwoong; Yu, Jung Ho; Baek, Woonhyuk; Lee, Chul-Ho; Son, Hae Jung; Hyeon, Taeghwan; Ko, Min Jae

    2015-11-24

    Copper-indium-selenide (CISe) quantum dots (QDs) are a promising alternative to the toxic cadmium- and lead-chalcogenide QDs generally used in photovoltaics due to their low toxicity, narrow band gap, and high absorption coefficient. Here, we demonstrate that the photovoltaic performance of CISe QD-sensitized solar cells (QDSCs) can be greatly enhanced simply by optimizing the thickness of ZnS overlayers on the QD-sensitized TiO2 electrodes. By roughly doubling the thickness of the overlayers compared to the conventional one, conversion efficiency is enhanced by about 40%. Impedance studies reveal that the thick ZnS overlayers do not affect the energetic characteristics of the photoanode, yet enhance the kinetic characteristics, leading to more efficient photovoltaic performance. In particular, both interfacial electron recombination with the electrolyte and nonradiative recombination associated with QDs are significantly reduced. As a result, our best cell yields a conversion efficiency of 8.10% under standard solar illumination, a record high for heavy metal-free QD solar cells to date.

  9. Crystallization of a perovskite film for higher performance solar cells by controlling water concentration in methyl ammonium iodide precursor solution.

    PubMed

    Adhikari, Nirmal; Dubey, Ashish; Gaml, Eman A; Vaagensmith, Bjorn; Reza, Khan Mamun; Mabrouk, Sally Adel Abdelsalam; Gu, Shaopeng; Zai, Jiantao; Qian, Xuefeng; Qiao, Qiquan

    2016-02-07

    An optimal small amount of water added into methyl ammonium iodide (MAI) solution in isopropyl alcohol (IPA) helps perovskite crystallization and leads to larger grain size from sequential deposition of perovskite films. The concentration of water was varied from 1% to 7% (vol% of IPA) in MAI solution and optical absorption, crystallization, morphology of perovskite films and their photovoltaic performance were studied in perovskite solar cells. 5% by volume was found to lead to preferential crystallization in the (110) plane with grain size about three times that of perovskite films prepared without adding water into the MAI solution. The optimal water concentration of 5% by volume in the MAI solution led to average perovskite grain size of ∼600 nm and solar cell efficiency of 12.42% at forward scan with a rate of 0.5 V s(-1). Device performance decreases after increasing water concentration beyond 5% in the MAI solution due to formation of the PbI2 phase. Transient photocurrent and photovoltage measurements show the shortest charge transport time at 0.99 μs and the longest charge carrier life time at 13.6 μs for perovskite films prepared from 5% water in MAI solution, which improved perovskite solar cell efficiency from 9.04% to 12.42%.

  10. Solar Collectors

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Solar Energy's solar panels are collectors for a solar energy system which provides heating for a drive-in bank in Akron, OH. Collectors were designed and manufactured by Solar Energy Products, a firm established by three former NASA employees. Company President, Frank Rom, an example of a personnel-type technology transfer, was a Research Director at Lewis Research Center, which conducts extensive solar heating and cooling research, including development and testing of high-efficiency flat-plate collectors. Rom acquired solar energy expertise which helped the company develop two types of collectors, one for use in domestic/commercial heating systems and the other for drying grain.

  11. Solar skylight

    DOEpatents

    Adamson, James C.

    1984-01-01

    A reflective shutter rotates within a skylight housing in such a fashion as to control solar energy thereby providing a combination of heating, lighting, and ventilation. The skylight housing has three faces: a glazed southern face, a glazed northern face, and an open downwardly oriented face to the interior of the structure. Counter-weighted pivot arms support the shutter at either end causing the center of rotation to pass through the center of gravity. The shutter has three basic positions: In the first position, during the winter day, the shutter closes off the northern face, allowing solar energy to enter directly into the supporting structure providing heat gain and daylighting. In the second position, during the winter night, the shutter closes off the open face to the interior, providing insulation between the structure and the skylight housing. In the third position, during the non-heating season, the shutter closes off the southern face blocking unwanted heat gain but allowing diffuse northern light to penetrate for daylighting. In this last position, a means is provided for ventilating by natural convection. The apparatus can be operated either manually or by motor.

  12. Controllable perovskite crystallization at a gas-solid interface for hole conductor-free solar cells with steady power conversion efficiency over 10%.

    PubMed

    Hao, Feng; Stoumpos, Constantinos C; Liu, Zhao; Chang, Robert P H; Kanatzidis, Mercouri G

    2014-11-19

    Depositing a pinhole-free perovskite film is of paramount importance to achieve high performance perovskite solar cells, especially in a heterojunction device format that is free of hole transport material (HTM). Here, we report that high-quality pinhole-free CH3NH3PbI3 perovskite film can be controllably deposited via a facile low-temperature (<150 °C) gas-solid crystallization process. The crystallite formation process was compared with respect to the conventional solution approach, in which the needle-shaped solvation intermediates (CH3NH3PbI3·DMF and CH3NH3PbI3·H2O) have been recognized as the main cause for the incomplete coverage of the resultant film. By avoiding these intermediates, the films crystallized at the gas-solid interface offer several beneficial features for device performance including high surface coverage, small surface roughness, as well as controllable grain size. Highly efficient HTM-free perovskite solar cells were constructed with these pinhole-free CH3NH3PbI3 films, exhibiting significant enhancement of the light harvesting in the long wavelength regime with respect to the conventional solution processed one. Overall, the gas-solid method yields devices with an impressive power conversion efficiency of 10.6% with high reproducibility displaying a negligible deviation of 0.1% for a total of 30 cells.

  13. Water contamination control: Guide for project planning and financing. Technical paper. Control de la contaminacion del agua: Guias para la planificacion y financiamiento de proyectos

    SciTech Connect

    Palange, R.C.; Zavala, A.

    1989-01-01

    This report provides guidelines for administrators, supervisors, and others involved in decision making to satisfy the need for facilities to control water contamination, but who possibly lack specialized training in engineering, economics, financial administration, or other pertinent specialties.

  14. A Transferencia do Controle da Educacao da Igreja para o Estado (The Transfer of Educational Control from the Church to the State).

    ERIC Educational Resources Information Center

    Silva, Marcos

    2000-01-01

    Analyzes the principal phases in the historical process of the occidental world that resulted in the transfer of educational control from the church to the state, demonstrating some of the consequences of this historic turn. (BT)

  15. Solar powered aircraft

    SciTech Connect

    Phillips, W.H.

    1983-11-15

    A cruciform wing structure for a solar powered aircraft is disclosed. Solar cells are mounted on horizontal wing surfaces. Wing surfaces with spanwise axis perpendicular to surfaces maintain these surfaces normal to the sun's rays by allowing aircraft to be flown in a controlled pattern at a large bank angle. The solar airplane may be of conventional design with respect to fuselage, propeller and tail, or may be constructed around a core and driven by propeller mechanisms attached near the tips of the airfoils.

  16. Solar collectors

    SciTech Connect

    Cassidy, V.M.

    1981-11-01

    Practical applications of solar energy in commercial, industrial and institutional buildings are considered. Two main types of solar collectors are described: flat plate collectors and concentrating collectors. Efficiency of air and hydronic collectors among the flat plate types are compared. Also several concentrators are described, including their sun tracking mechanisms. Descriptions of some recent solar installations are presented and a list representing the cross section of solar collector manufacturers is furnished.

  17. Solar Equipment

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A medical refrigeration and a water pump both powered by solar cells that convert sunlight directly into electricity are among the line of solar powered equipment manufactured by IUS (Independent Utility Systems) for use in areas where conventional power is not available. IUS benefited from NASA technology incorporated in the solar panel design and from assistance provided by Kerr Industrial Applications Center.

  18. Solar reflector

    SciTech Connect

    Stone, D. C.

    1981-02-17

    A solar reflector having a flexible triangular reflective sheet or membrane for receiving and reflecting solar energy therefrom. The reflector is characterized by the triangular reflective sheet which is placed under tension thereby defining a smooth planar surface eliminating surface deflection which heretofore has reduced the efficiency of reflectors or heliostats used in combination for receiving and transmitting solar energy to an absorber tower.

  19. Buying Solar.

    ERIC Educational Resources Information Center

    Dawson, Joe

    Presented are guidelines for buying solar systems for the individual consumer. This is intended to help the consumer reduce many of the risks associated with the purchase of solar systems, particularly the risks of fraud and deception. Engineering terms associated with solar technology are presented and described to enable the consumer to discuss…

  20. Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

    SciTech Connect

    None,

    1981-09-01

    Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

  1. High-efficiency inverted polymer solar cells controlled by the thickness of polyethylenimine ethoxylated (PEIE) interfacial layers.

    PubMed

    Li, Ping; Wang, Gang; Cai, Lun; Ding, Baofu; Zhou, Dachen; Hu, Yi; Zhang, Yujun; Xiang, Jin; Wan, Keming; Chen, Lijia; Alameh, Kamal; Song, Qunliang

    2014-11-21

    In this work, we investigate the effect of the thickness of the polyethylenimine ethoxylated (PEIE) interface layer on the performance of two types of polymer solar cells based on inverted poly(3-hexylthiophene) (P3HT):phenyl C61-butryric acid methyl ester (PCBM) and thieno[3,4-b]thiophene/benzodithiophene (PTB7):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM). Maximum power conversion efficiencies of 4.18% and 7.40% were achieved at a 5.02 nm thick PEIE interface layer, for the above-mentioned solar cell types, respectively. The optimized PEIE layer provides a strong enough dipole for the best charge collection while maintaining charge tunneling ability. Optical transmittance and atomic force microscopy measurements indicate that all PEIE films have the same high transmittance and smooth surface morphology, ruling out the influence of the PEIE layer on these two parameters. The measured external quantum efficiencies for the devices with thick PEIE layers are quite similar to those of the optimized devices, indicating the poor charge collection ability of thick PEIE layers. The relatively low performance of devices with a PEIE layer of thickness less than 5 nm is the result of a weak dipole and partial coverage of the PEIE layer on ITO.

  2. Controlled Deposition and Performance Optimization of Perovskite Solar Cells Using Ultrasonic Spray-Coating of Photoactive Layers.

    PubMed

    Chang, Wei-Chieh; Lan, Ding-Hung; Lee, Kun-Mu; Wang, Xiao-Feng; Liu, Cheng-Liang

    2016-12-27

    This study investigated a new film-deposition technique, ultrasonic spray-coating, for use in the production of a photoactive layer of perovskite solar cells. Stable atomization and facile fabrication of perovskite thin films by ultrasonic spray-coating were achieved in a one-step method through manipulating the ink formulation (e.g., solution concentration, precursor composition, and mixing solvent ratio) and the drying kinetics (e.g., post-annealing temperature). The performance of the perovskite solar cells was mainly influenced by the intrinsic film morphology and crystalline orientation of the deposited perovskite layer. By suitable optimization of the spreading and drying conditions of the ink, ultrasonic spray-coated perovskite photovoltaic devices were obtained with a maximum power conversion efficiency of 11.30 %, a fill factor of 73.6 %, a short-circuit current of 19.7 mA cm(-1) , and an open-circuit voltage of 0.78 V, respectively. Notably, the average power efficiency reached above 10 %, attributed to the large flower-like perovskite crystal with orientation along the (1 1 2)/(2 0 0) and (2 2 4)/(4 0 0) directions. Thus, the ultrasonic spray-coating method for perovskite photoactive layers, combining advantages of good photovoltaic performance results and benefits from cost and processing, has the potential for large-scale commercial production.

  3. Solar flair.

    PubMed Central

    Manuel, John S

    2003-01-01

    Design innovations and government-sponsored financial incentives are making solar energy increasingly attractive to homeowners and institutional customers such as school districts. In particular, the passive solar design concept of daylighting is gaining favor among educators due to evidence of improved performance by students working in daylit classrooms. Electricity-generating photovoltaic systems are also becoming more popular, especially in states such as California that have high electric rates and frequent power shortages. To help spread the word about solar power, the U.S. Department of Energy staged its first-ever Solar Decathlon in October 2002. This event featured solar-savvy homes designed by 14 college teams. PMID:12573926

  4. Solar Meter

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The instrument pictured is an inexpensive solar meter which is finding wide acceptance among architects, engineers and others engaged in construction of solar energy facilities. It detects the amount of solar energy available at a building site, information necessary to design the most efficient type of solar system for a particular location. Incorporating technology developed by NASA's Lewis Research Center, the device is based upon the solar cell, which provides power for spacecraft by converting the sun's energy to electricity. The meter is produced by Dodge Products, Inc., Houston, Texas, a company formed to bring the technology to the commercial marketplace.

  5. Solar flair.

    PubMed

    Manuel, John S

    2003-02-01

    Design innovations and government-sponsored financial incentives are making solar energy increasingly attractive to homeowners and institutional customers such as school districts. In particular, the passive solar design concept of daylighting is gaining favor among educators due to evidence of improved performance by students working in daylit classrooms. Electricity-generating photovoltaic systems are also becoming more popular, especially in states such as California that have high electric rates and frequent power shortages. To help spread the word about solar power, the U.S. Department of Energy staged its first-ever Solar Decathlon in October 2002. This event featured solar-savvy homes designed by 14 college teams.

  6. Un modelo para el control de calidad academica de los textos de instruccion a distancia (A Model for Controlling the Academic Quality of Distance Education Texts).

    ERIC Educational Resources Information Center

    Bolanos-Mora, Guiselle; And Others

    1992-01-01

    In response to the need for a system of control over the academic quality of distance education texts, this article proposes a methodological model based on criteria that evaluate written materials based on their instructional quality, design, and production. A discussion and figures evaluate educational aspects of content, communication,…

  7. Solar Energy: Solar System Economics.

    ERIC Educational Resources Information Center

    Knapp, Henry H., III

    This module on solar system economics is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies.…

  8. Solar Sailing

    NASA Technical Reports Server (NTRS)

    Johnson, Les

    2009-01-01

    Solar sailing is a topic of growing technical and popular interest. Solar sail propulsion will make space exploration more affordable and offer access to destinations within (and beyond) the solar system that are currently beyond our technical reach. The lecture will describe solar sails, how they work, and what they will be used for in the exploration of space. It will include a discussion of current plans for solar sails and how advanced technology, such as nanotechnology, might enhance their performance. Much has been accomplished recently to make solar sail technology very close to becoming an engineering reality and it will soon be used by the world s space agencies in the exploration of the solar system and beyond. The first part of the lecture will summarize state-of-the-art space propulsion systems and technologies. Though these other technologies are the key to any deep space exploration by humans, robots, or both, solar-sail propulsion will make space exploration more affordable and offer access to distant and difficult destinations. The second part of the lecture will describe the fundamentals of space solar sail propulsion and will describe the near-, mid- and far-term missions that might use solar sails as a propulsion system. The third part of the lecture will describe solar sail technology and the construction of current and future sailcraft, including the work of both government and private space organizations.

  9. D-sorbitol-induced phase control of TiO2 nanoparticles and its application for dye-sensitized solar cells.

    PubMed

    Shaikh, Shoyebmohamad F; Mane, Rajaram S; Min, Byoung Koun; Hwang, Yun Jeong; Joo, Oh-shim

    2016-02-09

    Using a simple hydrothermal synthesis, the crystal structure of TiO2 nanoparticles was controlled from rutile to anatase using a sugar alcohol, D-sorbitol. Adding small amounts of D-sorbitol to an aqueous TiCl4 solution resulted in changes in the crystal phase, particle size, and surface area by affecting the hydrolysis rate of TiCl4. These changes led to improvements of the solar-to-electrical power conversion efficiency (η) of dye-sensitized solar cells (DSSC) fabricated using these nanoparticles. A postulated reaction mechanism concerning the role of D-sorbitol in the formation of rutile and anatase was proposed. Fourier-transform infrared spectroscopy, (13)C NMR spectroscopy, and dynamic light scattering analyses were used to better understand the interaction between the Ti precursor and D-sorbitol. The crystal phase and size of the synthesized TiO2 nanocrystallites as well as photovoltaic performance of the DSSC were examined using X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and photocurrent density-applied voltage spectroscopy measurement techniques. The DSSC fabricated using the anatase TiO2 nanoparticles synthesized in the presence of D-sorbitol, exhibited an enhanced η (6%, 1.5-fold improvement) compared with the device fabricated using the rutile TiO2 synthesized without D-sorbitol.

  10. D-sorbitol-induced phase control of TiO2 nanoparticles and its application for dye-sensitized solar cells

    PubMed Central

    Shaikh, Shoyebmohamad F.; Mane, Rajaram S.; Min, Byoung Koun; Hwang, Yun Jeong; Joo, Oh-shim

    2016-01-01

    Using a simple hydrothermal synthesis, the crystal structure of TiO2 nanoparticles was controlled from rutile to anatase using a sugar alcohol, D-sorbitol. Adding small amounts of D-sorbitol to an aqueous TiCl4 solution resulted in changes in the crystal phase, particle size, and surface area by affecting the hydrolysis rate of TiCl4. These changes led to improvements of the solar-to-electrical power conversion efficiency (η) of dye-sensitized solar cells (DSSC) fabricated using these nanoparticles. A postulated reaction mechanism concerning the role of D-sorbitol in the formation of rutile and anatase was proposed. Fourier-transform infrared spectroscopy, 13C NMR spectroscopy, and dynamic light scattering analyses were used to better understand the interaction between the Ti precursor and D-sorbitol. The crystal phase and size of the synthesized TiO2 nanocrystallites as well as photovoltaic performance of the DSSC were examined using X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and photocurrent density-applied voltage spectroscopy measurement techniques. The DSSC fabricated using the anatase TiO2 nanoparticles synthesized in the presence of D-sorbitol, exhibited an enhanced η (6%, 1.5-fold improvement) compared with the device fabricated using the rutile TiO2 synthesized without D-sorbitol. PMID:26857963

  11. Highly efficient CdS/CdSe-sensitized solar cells controlled by the structural properties of compact porous TiO2 photoelectrodes.

    PubMed

    Zhang, Quanxin; Guo, Xiaozhi; Huang, Xiaoming; Huang, Shuqing; Li, Dongmei; Luo, Yanhong; Shen, Qing; Toyoda, Taro; Meng, Qingbo

    2011-03-14

    At present, the photovoltaic performance of quantum dot-sensitized solar cells (QDSCs) is still much lower than conventional DSCs. Appropriate porous TiO(2) photoanodes for QDSCs need to be further investigated, and optimization of the nanoparticle-based photoanodes is highly desirable as well. In this article, the influence of the structural properties of various TiO(2) photoanodes on CdS/CdSe-sensitized solar cells have been systematically studied. Quantitative analyses of light-harvesting efficiency (LHE) and electron-transfer yield (Φ(ET)) for the QDSCs are investigated for the first time. It is revealed that the LHE increases in the long wavelength region with the addition of large size TiO(2) particles to the transparent film. In the meantime, the balance between the light scattering and surface area also needs to be controlled, which can significantly restrain the dark current of the device. A double-layer photoanodic structure can give 4.92% of light-to-electricity conversion efficiency with a photoactive area of 0.15 cm(2).

  12. D-sorbitol-induced phase control of TiO2 nanoparticles and its application for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Shaikh, Shoyebmohamad F.; Mane, Rajaram S.; Min, Byoung Koun; Hwang, Yun Jeong; Joo, Oh-Shim

    2016-02-01

    Using a simple hydrothermal synthesis, the crystal structure of TiO2 nanoparticles was controlled from rutile to anatase using a sugar alcohol, D-sorbitol. Adding small amounts of D-sorbitol to an aqueous TiCl4 solution resulted in changes in the crystal phase, particle size, and surface area by affecting the hydrolysis rate of TiCl4. These changes led to improvements of the solar-to-electrical power conversion efficiency (η) of dye-sensitized solar cells (DSSC) fabricated using these nanoparticles. A postulated reaction mechanism concerning the role of D-sorbitol in the formation of rutile and anatase was proposed. Fourier-transform infrared spectroscopy, 13C NMR spectroscopy, and dynamic light scattering analyses were used to better understand the interaction between the Ti precursor and D-sorbitol. The crystal phase and size of the synthesized TiO2 nanocrystallites as well as photovoltaic performance of the DSSC were examined using X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and photocurrent density-applied voltage spectroscopy measurement techniques. The DSSC fabricated using the anatase TiO2 nanoparticles synthesized in the presence of D-sorbitol, exhibited an enhanced η (6%, 1.5-fold improvement) compared with the device fabricated using the rutile TiO2 synthesized without D-sorbitol.

  13. p- to n-type conductivity transition in 1.0 eV GaInNAs solar cells controlled by the V/III ratio

    SciTech Connect

    Langer, Fabian Perl, Svenja; Kamp, Martin; Höfling, Sven

    2015-02-09

    In this work, we report a p- to n-type conductivity transition of GaInNAs (1.0 eV bandgap) layers in p-i-n dilute nitride solar cells continuously controlled by the V/III ratio during growth. Near the transition region, we were able to produce GaInNAs layers with very low effective electrically active doping concentrations resulting in wide depleted areas. We obtained internal quantum efficiencies (IQEs) up to 85% at 0.2 eV above the bandgap. However, the high IQE comes along with an increased dark current density resulting in a decreased open circuit voltage of about 0.2 V. This indicates the formation of non-radiant defect centers related to the p-type to n-type transition. Rapid-thermal annealing of the solar cells on the one hand helps to anneal some of these defects but on the other hand increases the effective doping concentrations.

  14. Proceedings of the second US Department of Energy environmental control symposium. Volume 2. Nuclear energy, conservation, and solar energy

    SciTech Connect

    1980-06-01

    These proceedings document the presentations given at the Second Environmental Control Symposium. Symposium presentations highlighted environmental control activities which span the entire DOE. Volume II contains papers relating to: environmental control aspects of nuclear energy use and development; nuclear waste management; renewable energy sources; transportation and building conservation (fuel economy, gasohol, building standards, and industry); and geothermal energy, power transmission, and energy storage. (DMC)

  15. Development of bifacial inverted polymer solar cells using a conductivity-controlled transparent PEDOT:PSS and a striped Au electrode on the hole collection side

    NASA Astrophysics Data System (ADS)

    Kuwabara, Takayuki; Katori, Shinji; Arima, Kazuhiro; Omura, Yoshihiro; Yamaguchi, Takahiro; Taima, Tetsuya; Takahashi, Kohshin

    2014-02-01

    An inverted bifacial polymer solar cell was developed using a conductivity-controlled transparent poly(3,4-ethylenedioxylenethiophene):poly(4-styrene sulfonic acid) (PEDOT:PSS) as a hole collection layer and a striped Au electrode with a large open aperture ratio (Rap) as a hole collection electrode. We investigated the performance of the device by varying the interelectrode distance of the striped Au electrode and the sheet resistance of the PEDOT:PSS film. The device using untreated Clevios P (PEDOT:PSS) showed a maximum electric output (Pw) in the Rap range of 50 to 65%. When alcohol-treated Clevios P (Clevios P+) with a lower electrical resistance was used, the maximum Pw increased by 40% compared with that of the device using Clevios P. The maximum Pw was obtained in the Rap range of 84% as the hole collection efficiency of the striped Au electrode improved with the decreased sheet resistance of the PEDOT:PSS.

  16. One-impulse targeting strategy for longitudinal drift control of geosynchronous spacecraft subject to tesseral harmonics and luni-solar gravity perturbations

    NASA Technical Reports Server (NTRS)

    Kechichian, J. A.

    1984-01-01

    Kamel's (1973) East-West Stationkeeping Analysis is extended and an algorithm is presented that targets the geosynchronous spacecraft to the ideal initial conditions starting from any given relative longitude deviation within a given tolerance deadband in order to repeat the ideal longitudinal drift cycle that results in the longest possible period of time between maneuvers. The motion description takes into account the perturbations introduced by earth's tesseral harmonics and by the luni-solar gravity, assuming a near-circular orbit that requires only the control of orbital energy to repeat the ideal drift cycle via a single impulsive velocity change. The location of the maneuver along the orbit is such that the post-Delta-V eccentricity is always minimized.

  17. Solar Simulator

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Oriel Corporation's simulators have a high pressure xenon lamp whose reflected light is processed by an optical system to produce a uniform solar beam. Because of many different types of applications, the simulators must be adjustable to replicate many different areas of the solar radiation spectrum. Simulators are laboratory tools for such purposes as testing and calibrating solar cells, or other solar energy systems, testing dyes, paints and pigments, pharmaceuticals and cosmetic preparations, plant and animal studies, food and agriculture studies and oceanographic research.

  18. Solar Physics

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    2000-01-01

    The areas of emphasis are: (1) develop theoretical models of the transient release of magnetic energy in the solar atmosphere, e.g., in solar flares, eruptive prominences, coronal mass ejections, etc.; (2) investigate the role of the Sun's magnetic field in the structuring of solar corona by the development of three-dimensional numerical models that describe the field configuration at various heights in the solar atmosphere by extrapolating the field at the photospheric level; (3) develop numerical models to investigate the physical parameters obtained by the ULYSSES mission; (4) develop numerical and theoretical models to investigate solar activity effects on the solar wind characteristics for the establishment of the solar-interplanetary transmission line; and (5) develop new instruments to measure solar magnetic fields and other features in the photosphere, chromosphere transition region and corona. We focused our investigation on the fundamental physical processes in solar atmosphere which directly effect our Planet Earth. The overall goal is to establish the physical process for the Sun-Earth connections.

  19. Tin doped indium oxide anodes with artificially controlled nano-scale roughness using segregated Ag nanoparticles for organic solar cells

    PubMed Central

    Kim, Hyo-Joong; Ko, Eun-Hye; Noh, Yong-Jin; Na, Seok-In; Kim, Han-Ki

    2016-01-01

    Nano-scale surface roughness in transparent ITO films was artificially formed by sputtering a mixed Ag and ITO layer and wet etching of segregated Ag nanoparticles from the surface of the ITO film. Effective removal of self-segregated Ag particles from the grain boundaries and surface of the crystalline ITO film led to a change in only the nano-scale surface morphology of ITO film without changes in the sheet resistance and optical transmittance. A nano-scale rough surface of the ITO film led to an increase in contact area between the hole transport layer and the ITO anode, and eventually increased the hole extraction efficiency in the organic solar cells (OSCs). The heterojunction OSCs fabricated on the ITO anode with a nano-scale surface roughness exhibited a higher power conversion efficiency of 3.320%, than that (2.938%) of OSCs made with the reference ITO/glass. The results here introduce a new method to improve the performance of OSCs by simply modifying the surface morphology of the ITO anodes. PMID:27640723

  20. Tin doped indium oxide anodes with artificially controlled nano-scale roughness using segregated Ag nanoparticles for organic solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Hyo-Joong; Ko, Eun-Hye; Noh, Yong-Jin; Na, Seok-In; Kim, Han-Ki

    2016-09-01

    Nano-scale surface roughness in transparent ITO films was artificially formed by sputtering a mixed Ag and ITO layer and wet etching of segregated Ag nanoparticles from the surface of the ITO film. Effective removal of self-segregated Ag particles from the grain boundaries and surface of the crystalline ITO film led to a change in only the nano-scale surface morphology of ITO film without changes in the sheet resistance and optical transmittance. A nano-scale rough surface of the ITO film led to an increase in contact area between the hole transport layer and the ITO anode, and eventually increased the hole extraction efficiency in the organic solar cells (OSCs). The heterojunction OSCs fabricated on the ITO anode with a nano-scale surface roughness exhibited a higher power conversion efficiency of 3.320%, than that (2.938%) of OSCs made with the reference ITO/glass. The results here introduce a new method to improve the performance of OSCs by simply modifying the surface morphology of the ITO anodes.

  1. Tin doped indium oxide anodes with artificially controlled nano-scale roughness using segregated Ag nanoparticles for organic solar cells.

    PubMed

    Kim, Hyo-Joong; Ko, Eun-Hye; Noh, Yong-Jin; Na, Seok-In; Kim, Han-Ki

    2016-09-19

    Nano-scale surface roughness in transparent ITO films was artificially formed by sputtering a mixed Ag and ITO layer and wet etching of segregated Ag nanoparticles from the surface of the ITO film. Effective removal of self-segregated Ag particles from the grain boundaries and surface of the crystalline ITO film led to a change in only the nano-scale surface morphology of ITO film without changes in the sheet resistance and optical transmittance. A nano-scale rough surface of the ITO film led to an increase in contact area between the hole transport layer and the ITO anode, and eventually increased the hole extraction efficiency in the organic solar cells (OSCs). The heterojunction OSCs fabricated on the ITO anode with a nano-scale surface roughness exhibited a higher power conversion efficiency of 3.320%, than that (2.938%) of OSCs made with the reference ITO/glass. The results here introduce a new method to improve the performance of OSCs by simply modifying the surface morphology of the ITO anodes.

  2. Controlled growth of Cu2ZnSnS4 (CZTS) thin films for heterojunction solar-cell applications

    NASA Astrophysics Data System (ADS)

    Inamdar, A. I.; Jeon, Ki-Young; Woo, Hyeon Seok; Jung, Woong; Im, Hyunsik; Kim, Hyungsang

    2012-05-01

    Cu2ZnSnS4 (CZTS) thin films (absorber layers) were successfully synthesized on glass substrates by using a RF magnetron sputtering system. The films were rapidly thermally annealed in a nitrogen atmosphere for 20 minutes to improve the crytallinity. The formation of kesterite structures (JCPDS-26-0575) in the film was confirmed using X-ray diffraction (XRD) measurements. The improved crytallinity of the CZTS with a (112) orientation was observed with increasing annealing temperature. The band gaps of all the as-deposited and annealed films were found to be in the range from 1.97 to 1.55 eV. The films' stoichiometry and morphologies were investigated using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX) measurements. The sample annealed at 500 °C showed a uniform granular structure with an elemental composition near stoichiometric CZTS. Next, a buffer layer of ZnS for a heterojuntion solar cell was fabricated using a chemical bath deposition (CBD) technique. The films adhered well, were optically transparent and had band gap energy of 3.6 eV.

  3. Solar-Cell String Conveyor

    NASA Technical Reports Server (NTRS)

    Frasch, W.; Ciavola, S.

    1982-01-01

    String-conveyor portion of solar-array assembly line holds silicon solar cells while assembled into strings and tested. Cells are transported collector-side-down, while uniform cell spacing and registration are maintained. Microprocessor on machine controls indexing of cells.

  4. Passive-solar construction handbook

    SciTech Connect

    Levy, E.; Evans, D.; Gardstein, C.

    1981-02-01

    Many of the basic elements of passive solar design are reviewed. Passive solar construction is covered according to system type, each system type discussion including a general discussion of the important design and construction issues which apply to the particular system and case studies illustrating designed and built examples of the system type. The three basic types of passive solar systems discussed are direct gain, thermal storage wall, and attached sunspace. Thermal performance and construction information is presented for typical materials used in passive solar collector components, storage components, and control components. Appended are an overview of analysis methods and a technique for estimating performance. (LEW)

  5. Management of plant species for controlling pests, by peasant farmers at Lagoa Seca, Paraíba state, Brazil: an ethnoecological approach

    PubMed Central

    Guimarães, Andréia de Souza; Mourão, José da Silva

    2006-01-01

    Ethnoecological knowledge may be understood as spontaneous knowledge, culturally referenced of any society's members, learned and transmitted through social interactions and that are targeted at resolution of daily routine situations. The traditional knowledge in small scale economy societies as well as the non-academic knowledge in urban-industrial societies might be included in this concept. An ethnoecological approach study was performed here on people living at the communities of Alvinho, Almeida, Chã do Marinho, Floriano, and Chã de Oiti, all located in the municipality of Lagoa Seca, Paraíba state, Northeast Brazil. The general objective pursued here was to study the knowledge that peasant farmers have on management of plant species utilized for pest control. For this, the methodological instruments employed here to investigate the ethnoecological knowledge were: direct observation, structured and semi-structured interviews, and tours conducted by local peasant farmers. We analyzed the data obtained under an emic/etic view and also by comparing the local knowledge with those obtained from the literature. The results showed that people in those communities utilize management alternatives for controlling pests, which are mainly: (i) fallowing; (ii) crop rotation; (iii) destruction of crop remains and fruits attacked by pests; (iv) alternations of crops with repellent plants; and/or (v) mixed cropping; (vi) insect's larvae covered with soil; (vii) crops irrigated abundantly; and (viii) soil preparation. The recovery and comprehension we get about this knowledge as well as the farmers' savoir faire, are extremely important to the revival of ancient agricultural practices, which have been forgotten due to advances in modern agriculture. The data obtained here showed that a huge body of knowledge the farmers have on many forms or strategies of management are generally compatible with scientific knowledge. PMID:17026748

  6. The solar terrestrial observatory

    NASA Technical Reports Server (NTRS)

    Chappell, C. R.

    1978-01-01

    The larger system of the earth environment is controlled externally by electromagnetic and particle energy from the sun. Recent studies have shown that the sun is a variable star with changes in its radiation which produce significant effects in the earth's climate and weather. The study of the solar-terrestrial system requires simultaneous, long-duration observations of the different elements or 'links' in the solar-terrestrial chain. Many investigations must be conducted in space from a vantage point above the earth's atmosphere where all of the sun's emissions can be observed free from atmospheric distortion, where the magnetospheric particles and fields can be measured directly, and where the atmosphere can be observed on a global scale. The extension of the Shuttle on-orbit capability in connection with the development of the power module will offer an important near-term step in an evolutionary process leading toward a permanent manned Solar Terrestrial Observatory capability in low-earth orbit. Attention is given to the required solar-terrestrial measurements, the operation of the Solar Terrestrial Observatory, and an evolutionary approach to the Solar Terrestrial Observatory.

  7. Solar Thermal Propulsion Test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. This image, taken during the test, depicts the light being concentrated into the focal point inside the vacuum chamber. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

  8. PbI2-Based Dipping-Controlled Material Conversion for Compact Layer Free Perovskite Solar Cells.

    PubMed

    Zheng, Enqiang; Wang, Xiao-Feng; Song, Jiaxing; Yan, Lulin; Tian, Wenjing; Miyasaka, Tsutomu

    2015-08-19

    A two-step sequential deposition method has been extensively employed to prepare the CH3NH3PbI3 active layer from the PbI2 precursor in perovskite solar cells (PSCs). The variation of the photovoltaic performance of PSCs made by this method was always attributed to different dipping times that induce complete/incomplete conversion of PbI2 into CH3NH3PbI3. To solve this issue, we employed a solvent vapor annealing (SVA) method to prepare PbI2 crystallites with large grain size for preparation of high quality perovskite. With this method, the increased PbI2 dipping time in CH3NH3I solution was found to reduce the photovoltaic performance of resulting PSCs without a significant change in PbI2/CH3NH3PbI3 contents in the perovskite films. We attribute this abnormal reduction of the photovoltaic performance to intercalation/deintercalation of the PbI2 core with a CH3NH3PbI3 shell, which causes the doping effect on both the PbI2 and CH3NH3PbI3 crystal lattices and the formation of a CH3NH3PbI3 capping layer on the surface, as revealed by UV-vis absorption, X-ray diffraction, FT-IR, and scanning electron microscope measurements. Based on our findings, a multistep dipping-drying process was employed as an alternative method to improve the crystalline quality. The method achieved power conversion efficiency up to 11.4% for the compact layer free PSC sharing a simple device structure of ITO/perovskite/spiro-OMeTAD/Ag.

  9. Solar Eclipse

    Atmospheric Science Data Center

    2013-04-16

    ... a solar eclipse where an observer on Earth can watch the Moon's shadow obscure more than 90% the Sun's disk, the Multiangle Imaging ... total solar eclipse of November 23, 2003. The path of the Moon's umbral shadow began in the Indian Ocean in the far Southern Hemisphere, ...

  10. Solar Eclipse

    Atmospheric Science Data Center

    2013-04-19

    ...   View Larger Image On June 10, 2002 the Moon obscured the central portion of the solar disk in a phenomenon known as an ... in which 99.6 percent of the solar disk was shadowed by the Moon, was situated in the central Pacific Ocean. Since there are no populated ...

  11. Solar Sprint

    ERIC Educational Resources Information Center

    Tabor, Richard; Anderson, Stephen

    2007-01-01

    In the "Solar Sprint" activity, students design, test, and race a solar-powered car built with Legos. The use of ratios is incorporated to simulate the actual work of scientists and engineers. This method encourages fourth-grade students to think about multiple variables and stimulates their curiosity when an activity doesn't come out as…

  12. Solar Technologies

    ERIC Educational Resources Information Center

    von Hippel, Frank; Williams, Robert H.

    1975-01-01

    As fossil fuels decrease in availability and environmental concerns increase, soalr energy is becoming a potential major energy source. Already solar energy is used for space heating in homes. Proposals for solar-electric generating systems include land-based or ocean-based collectors and harnessing wind and wave power. Photosynthesis can also…

  13. Adaptive, full-spectrum solar energy system

    DOEpatents

    Muhs, Jeffrey D.; Earl, Dennis D.

    2003-08-05

    An adaptive full spectrum solar energy system having at least one hybrid solar concentrator, at least one hybrid luminaire, at least one hybrid photobioreactor, and a light distribution system operably connected to each hybrid solar concentrator, each hybrid luminaire, and each hybrid photobioreactor. A lighting control system operates each component.

  14. Solar-powered hot-water system

    NASA Technical Reports Server (NTRS)

    Collins, E. R.

    1979-01-01

    Hot-water system requires no external power except solar energy. System is completely self-controlling. It includes solar-powered pump, solar-thermally and hydrothermally operated valves, and storage tank filled with open-celled foam, to maintain thermal stratification in stored water.

  15. Hybrid solar lighting systems and components

    DOEpatents

    Muhs, Jeffrey D.; Earl, Dennis D.; Beshears, David L.; Maxey, Lonnie C.; Jordan, John K.; Lind, Randall F.

    2007-06-12

    A hybrid solar lighting system and components having at least one hybrid solar concentrator, at least one fiber receiver, at least one hybrid luminaire, and a light distribution system operably connected to each hybrid solar concentrator and each hybrid luminaire. A controller operates each component.

  16. Hybrid solar lighting distribution systems and components

    DOEpatents

    Muhs, Jeffrey D.; Earl, Dennis D.; Beshears, David L.; Maxey, Lonnie C.; Jordan, John K.; Lind, Randall F.

    2011-07-05

    A hybrid solar lighting distribution system and components having at least one hybrid solar concentrator, at least one fiber receiver, at least one hybrid luminaire, and a light distribution system operably connected to each hybrid solar concentrator and each hybrid luminaire. A controller operates all components.

  17. Controlled electrodeposition of Cu-Ga from a deep eutectic solvent for low cost fabrication of CuGaSe2 thin film solar cells.

    PubMed

    Steichen, Marc; Thomassey, Matthieu; Siebentritt, Susanne; Dale, Phillip J

    2011-03-14

    The electrochemical deposition of Ga and Cu-Ga alloys from the deep eutectic solvent choline chloride/urea (Reline) is investigated to prepare CuGaSe(2) (CGS) semiconductors for their use in thin film solar cells. Ga electrodeposition is difficult from aqueous solution due to its low standard potential and the interfering hydrogen evolution reaction (HER). Ionic liquid electrolytes offer a better thermal stability and larger potential window and thus eliminate the interference of solvent breakdown reactions during Ga deposition. We demonstrate that metallic Ga can be electrodeposited from Reline without HER interference with high plating efficiency on Mo and Cu electrodes. A new low cost synthetic route for the preparation of CuGaSe(2) absorber thin films is presented and involves the one-step electrodeposition of Cu-Ga precursors from Reline followed by thermal annealing. Rotating disk electrode (RDE) cyclic voltammetry (CV) is used in combination with viscosity measurements to determine the diffusion coefficients of gallium and copper ions in Reline. The composition of the codeposited Cu-Ga precursor layers can be controlled to form Cu/Ga thin films with precise stoichiometry, which is important for achieving good optoelectronic properties of the final CuGaSe(2) absorbers. The morphology, the chemical composition and the crystal structure of the deposited thin films are analysed by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX) and X-ray diffraction (XRD). Annealing of the Cu-Ga films in a selenium atmosphere allowed the formation of high quality CuGaSe(2) absorber layers. Completed CGS solar cells achieved a 4.1% total area power conversion efficiency.

  18. Solar atrium: A hybrid solar heating and cooling system

    NASA Astrophysics Data System (ADS)

    Ueland, M.

    1980-06-01

    The atrium is designed to be constructed of materials and equipment that are economical and readily available. Cost effectiveness of installation and operation is a primary design objective. The solar atrium is a further development of efforts begun in the 1930's and 1940's to design houses that would obtain a major portion of their heating from the Sun. The early solar house experiments proved the benefits of large glazed areas for trapping solar energy. However, they were not equipped to collect and store surplus solar energy, nor were they equipped to control heat losses through glass areas at night or during cloudy days. The solar atrium incorporates the large glass areas of the earlier houses and adds facilities for heat storage and control of heat losses through glass. Progress and plans are outlined.

  19. STATCOM-Based Wind-Solar-Hydro Electric Power System with Modified Real and Reactive Power Controls

    NASA Astrophysics Data System (ADS)

    Ram Prabhakar, J.; Ragavan, K.

    2014-01-01

    This paper presents a control of distributed generation (DG) system subjected to sudden rise in demand, faults on the distribution feeder and unbalanced load condition. The effects of line to ground faults on the system are investigated and control measures are taken to stabilize the generator speed and to improve voltage quality at the point of common coupling (PCC). The static shunt compensator (STATCOM) is connected at PCC to provide voltage support during sudden demand rise and fault on feeder. Moreover, the STATCOM control is devised such that even during unbalanced load condition the converter current and hydro-turbine-driven induction generator current is balanced. Owing to this, the double power frequency oscillations in the dc-link voltage and torque pulsations in generator can be averted. The STATCOM also supplies reactive power to the load. In addition to this, generation-demand mismatch is moderated using real and reactive power controllers. To demonstrate the performance of the DG system with the said control approach, model of system is simulated in Matlab-Simulink environment and the results are presented.

  20. Solar Variability Controls on Rainfall in the Last Millennia: Evidence from a Highly Resolved Stalagmite Record from DeSoto Caverns (USA)

    NASA Astrophysics Data System (ADS)

    Aharon, P.; Lambert, W.; Hellstrom, J.

    2009-12-01

    Moisture transport from the Gulf of Mexico (GOM) inland has a considerable influence on both regional and continental rainfall patterns. Recent episodes of drought in the Southeastern USA exposed the vulnerability of the regional infrastructure to climate changes and gave rise to inter-state “water wars”. In order to better understand the cause of these periodic droughts and their controlling climate factors we have initiated a study of stalagmites from the DeSoto Caverns (Alabama, USA) that intersect the moisture flow from GOM. Combination of unusually high growth rates (up to 2 mm/decade), prominent dark and light seasonal layers, pristine aragonite mineralogy, precise U/Th dates acquired from mg-size samples and tight sampling (n=195) afforded generation of biannual (δ18O and δ13C of exceptional clarity spanning the last 700 yrs. The stalagmite (DSSG1) top yields isotope values (δ18O=-5.5 per-mill VPDB; δ13C=-10.1 per-mill VPDB) that are in good agreement with the predicted equilibrium isotope values. The oxygen and carbon isotope records exhibit a number of alternating negative and positive phase changes of solar maxima and minima, respectively, as being primarily an expression of rapid shifts in rainfall sourced from GOM moisture and alternating between low and high rainfall intervals. The low and high rainfall intervals discerned in the stalagmite correspond to contemporaneous SST rise and fall in GOM and the Caribbean of about 1 oC amplitude. We suggest that small but measurable SST changes in the Western Hemisphere Warm Pool (WHWP), controlled by solar

  1. Controlled fabrication of mesoporous TiO2 hierarchical structures as scattering layers to enhance the power conversion efficiency of dye-sensitized solar cells.

    PubMed

    Hwang, Dae-Kue; Sung, Shi-Joon

    2016-11-09

    To meet the nanofabrication requirements, such as control of structure and scalability, we investigated an electrospray-based method to manufacture scattering layers (SLs) for dye-sensitized solar cells (DSSCs). TiO2 spherical and disk-shaped particles with a large surface area, high crystallinity, uniform nanostructure and good light scattering properties were fabricated via a simple electrospray method. We showed how the morphology and structure of the resulting films can be controlled by varying the droplet evaporation rates before impact on the substrate. Thus, by tuning the process conditions, high-quality TiO2 spheres and disks were obtained. Then, these mesoporous TiO2 particles were used as the SLs in photoelectrodes, which resulted in enhanced power conversion efficiency (PCE). Compared with conventional SLs (8.45%), DSSCs based on spherical and disk-shaped particle SLs yield higher PCEs of 9.0% and 9.53%, respectively. This is because the generated TiO2 spheres and disks provide a large surface area and exhibit excellent light scattering capabilities, allowing a low total internal resistance and a long electron lifetime.

  2. Nanocrystal Solar Cells

    SciTech Connect

    Gur, Ilan

    2006-01-01

    This dissertation presents the results of a research agenda aimed at improving integration and stability in nanocrystal-based solar cells through advances in active materials and device architectures. The introduction of 3-dimensional nanocrystals illustrates the potential for improving transport and percolation in hybrid solar cells and enables novel fabrication methods for optimizing integration in these systems. Fabricating cells by sequential deposition allows for solution-based assembly of hybrid composites with controlled and well-characterized dispersion and electrode contact. Hyperbranched nanocrystals emerge as a nearly ideal building block for hybrid cells, allowing the controlled morphologies targeted by templated approaches to be achieved in an easily fabricated solution-cast device. In addition to offering practical benefits to device processing, these approaches offer fundamental insight into the operation of hybrid solar cells, shedding light on key phenomena such as the roles of electrode-contact and percolation behavior in these cells. Finally, all-inorganic nanocrystal solar cells are presented as a wholly new cell concept, illustrating that donor-acceptor charge transfer and directed carrier diffusion can be utilized in a system with no organic components, and that nanocrystals may act as building blocks for efficient, stable, and low-cost thin-film solar cells.

  3. In-situ microfluidic controlled, low temperature hydrothermal growth of nanoflakes for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Zhao, Chao; Zhang, Jia; Hu, Yue; Robertson, Neil; Hu, Ping An; Child, David; Gibson, Desmond; Fu, Yong Qing

    2015-12-01

    In this paper, an in-situ microfluidic control unit (MCU) was designed and applied in a hydrothermal synthesis process, which provides an easy way to localize liquid-phase reaction and realize selective synthesis and direct growth of nanostructures as well as their morphology, all in a low-temperature and atmospheric environment. The morphology was controlled through controlling the amount of additivities using the MCU. This achieved a facile fabrication of Al doped ZnO (AZO) nanoflakes vertically grown on flexible polymer substrates with enhanced light scattering and dye loading capabilities. Flexible DSSCs with a significant enhancement (410% compare to ZnO NRs based devices) in power conversion efficiency were obtained using AZO nanoflake photoanodes of 6 μm thick, due to the enhancement in electron mobility and reduction in recombination. This hydrothermal synthesis using the in-situ MCU provides an efficient and scalable technique to synthesize controllable nanostructures with characteristics of easy set-up, low energy consumption and low cost.

  4. In-situ microfluidic controlled, low temperature hydrothermal growth of nanoflakes for dye-sensitized solar cells

    PubMed Central

    Zhao, Chao; Zhang, Jia; Hu, Yue; Robertson, Neil; Hu, Ping An; Child, David; Gibson, Desmond; Fu, Yong Qing

    2015-01-01

    In this paper, an in-situ microfluidic control unit (MCU) was designed and applied in a hydrothermal synthesis process, which provides an easy way to localize liquid-phase reaction and realize selective synthesis and direct growth of nanostructures as well as their morphology, all in a low-temperature and atmospheric environment. The morphology was controlled through controlling the amount of additivities using the MCU. This achieved a facile fabrication of Al doped ZnO (AZO) nanoflakes vertically grown on flexible polymer substrates with enhanced light scattering and dye loading capabilities. Flexible DSSCs with a significant enhancement (410% compare to ZnO NRs based devices) in power conversion efficiency were obtained using AZO nanoflake photoanodes of 6 μm thick, due to the enhancement in electron mobility and reduction in recombination. This hydrothermal synthesis using the in-situ MCU provides an efficient and scalable technique to synthesize controllable nanostructures with characteristics of easy set-up, low energy consumption and low cost. PMID:26631685

  5. Solar Power Satellite antenna phase control system hardware simulation, phase 4. Volume 2: Analytical simulation of SPS system performance

    NASA Technical Reports Server (NTRS)

    Lindsey, W. C.; Kantak, A. V.; Chie, C. M.

    1981-01-01

    The pilot signal parameter optimization and power transponder analyses are presented. The SPS antenna phase control system is modeled and the hardware simulation study described. Ionospheric and system phase error effects and the effects of high power amplifier phase and amplitude jitters are considered. Parameter optimization of the spread spectrum receiver, consisting of the carrier tracking loop and the code tracking loop, is described.

  6. Solar ponds

    SciTech Connect

    Jayadev, T.S.; Edesess, M.

    1980-04-01

    This report first describes the different types of solar ponds including the nonconvecting salt gradient pond and various saltless pond designs. It then discusses the availability and cost of salts for salt gradient ponds, and compares the economics of salty and saltless ponds as a function of salt cost. A simple computational model is developed to approximate solar pond performance. This model is later used to size solar ponds for district heating and industrial process heat applications. For district heating, ponds are sized to provide space conditioning for a group of homes, in different regions of the United States. Size requirements is on the order of one acre for a group of 25 to 50 homes. An economic analysis is performed of solar ponds used in two industrial process heat applications. The analysis finds that solar ponds are competitive when conventional heat sources are priced at $5 per million Btu and expected to rise in price at a rate of 10% per year. The application of solar ponds to the generation of electricity is also discussed. Total solar pond potential for displacing conventional energy sources is estimated in the range of from one to six quadrillion Btu per year in the near and intermediate future.

  7. Solar Cell Panel and the Method for Manufacturing the Same

    NASA Technical Reports Server (NTRS)

    Richards, Benjamin C. (Inventor); Sarver, Charles F. (Inventor); Naidenkova, Maria (Inventor)

    2016-01-01

    According to an aspect of an embodiment of the present disclosure, there is provided a solar cell panel and a method for manufacturing the same. The solar cell panel comprises: a solar cell for generating electric power from sunlight; a coverglass for covering the solar cell; transparent shims, which are disposed between the solar cell and the coverglass at the points where the distance between the solar cell and the coverglass needs to be controlled, and form a space between the solar cell and the coverglass; and adhesive layer, which fills the space between the solar cell and the coverglass and has the thickness the same as that of the transparent shims.

  8. Solar pruritus.

    PubMed

    Bech-Thomsen, N; Thomsen, K

    1995-11-01

    A case of solar pruritus is reported. Severe pruritus of the back, shoulders and upper lateral aspects of the arms, without any eruption, developed in a 28-year-old outdoor worker during 4 to 6 weeks of intensive solar exposure. The pruritus was intense and described as a burning sensation deep in the skin. Only a few excoriations and slight xerosis were found. Solar pruritus or brachioradial pruritus is a condition primarily seen in Caucasian people living in the tropics or subtropics. Previously the disease has only been reported once outside these areas.

  9. Solar Two

    SciTech Connect

    Not Available

    1998-04-01

    Solar Two is a concentrating solar power plant that can supply electric power on demand to the local utility, Southern California Edison Company. It can do so because it operates not only during sunny parts of the day, but it can store enough thermal energy from the sun to operate during cloudy periods and after dark, for up to three hours, at its rated output of 10 megawatts (MW). For the first time ever, a utility scale solar power plant can supply electricity when the utility needs it most, to satisfy the energy requirements of its customers.

  10. Manhattan Solar Cannon

    NASA Astrophysics Data System (ADS)

    Treffers, Richard R.; Loisos, George; Ubbelohde, Susan; Douglas, Susanna; Pintos, Eduardo; Mulherin, James; Pasley, David

    2015-01-01

    We describe a 2.4 m hexagonal solar collector atop a Manhattan office building used for a solar / arts project. The collector uses an afocal design to concentrate the sunlight into a 0.6 m diameter beam which is directed by mirrors into a 80 m long fiber optic sculpture which descends an interior stairwell. The collector is fully steerable and follows the sun each day robotically. The control system and the optical design of the collector as well as the fiber optic sculpture will be discussed.

  11. Solar fuels

    NASA Astrophysics Data System (ADS)

    Viitanen, M.

    1990-12-01

    The aim of this paper is to give a review concerning the storage of solar energy by converting it to chemical energy. This is based on several articles published during the last fifteen years. The methods to convert solar energy to chemical energy, e.g., to produce hydrogen, can be divided into three different methods. The most common one is probably the usage of solar cells; thus the solar energy is first converted into electrical energy and further the water is split electrochemically to produce hydrogen. It could be also done in a photoelectrochemical cell, or simply photochemically. A photobiological system can also be considered as a photochemical system, although it is discussed separately from the photochemical systems. These three last mentioned methods will be discussed in this paper.

  12. Solar Nexus.

    ERIC Educational Resources Information Center

    Murphy, Jim

    1980-01-01

    The design team for the Solar Energy Research Institute (SERI) has pushed the state of the energy art to its current limits for the initial phase, with provisions for foreseeable and even speculative future applications. (Author/MLF)

  13. Solar chulha

    NASA Astrophysics Data System (ADS)

    Jadhao, P. H.; Patrikar, S. R.

    2016-05-01

    The main goal of the proposed system is to transfer energy from sun to the cooking load that is located in the kitchen. The energy is first collected by the solar collector lens system and two curve bars of same radius of curvature are mounted parallel and adjacent to each other at different height the solar collector is clamed on this two bars such that solar collector is exactly perpendicular to sunlight. The topology includes an additional feature which is window in the wall through which the beam is collimated is directed in the of kitchen. The solar energy that is collected is directed by the mirror system into the kitchen, where it is redirected to cooking platform located in the kitchen. The special feature in this system full Indian meal can be made since cooking platform is indoors.

  14. Nanoimprinted polymer solar cell.

    PubMed

    Yang, Yi; Mielczarek, Kamil; Aryal, Mukti; Zakhidov, Anvar; Hu, Walter

    2012-04-24

    Among the various organic photovoltaic devices, the conjugated polymer/fullerene approach has drawn the most research interest. The performance of these types of solar cells is greatly determined by the nanoscale morphology of the two components (donor/acceptor) and the molecular orientation/crystallinity in the photoactive layer. A vertically bicontinuous and interdigitized heterojunction between donor and acceptor has been regarded as one of the ideal structures to enable both efficient charge separation and transport. Synergistic control of polymer orientation in the nanostructured heterojunction is also critical to improve the performance of polymer solar cells. Nanoimprint lithography has emerged as a new approach to simultaneously control both the heterojunction morphology and polymer chains in organic photovoltaics. Currently, in the area of nanoimprinted polymer solar cells, much progress has been achieved in the fabrication of nanostructured morphology, control of molecular orientation/crystallinity, deposition of acceptor materials, patterned electrodes, understanding of structure-property correlations, and device performance. This review article summarizes the recent studies on nanoimprinted polymer solar cells and discusses the outstanding challenges and opportunities for future work.

  15. Solar Pump

    NASA Technical Reports Server (NTRS)

    Pique, Charles

    1987-01-01

    Proposed pump moves liquid by action of bubbles formed by heat of sun. Tube of liquid having boiling point of 100 to 200 degrees F placed at focal axis of cylindrical reflector. Concentrated sunlight boils liquid at focus, and bubbles of vapor rise in tube, carrying liquid along with them. Pressure difference in hot tube sufficient to produce flow in large loop. Used with conventional flat solar heating panel in completely solar-powered heat-storage system.

  16. Solar Cells

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The Heat Exchanger Method (HEM) produces high efficiency crystal ingots in an automated well-insulated furnace offering low equipment, labor and energy costs. The "grown" silicon crystals are used to make solar cells, or photovoltaic cells which convert sunlight directly into electricity. The HEM method is used by Crystal Systems, Inc. and was developed under a NASA/Jet Propulsion Laboratory contract. The square wafers which are the result of the process are sold to companies manufacturing solar panels.

  17. Solar Schematic

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The home shown at right is specially designed to accommodate solar heating units; it has roof planes in four directions, allowing placement of solar collectors for best exposure to the sun. Plans (bottom) and complete working blueprints for the solar-heated house are being marketed by Home Building Plan Service, Portland, Oregon. The company also offers an inexpensive schematic (center) showing how a homeowner only moderately skilled in the use of tools can build his own solar energy system, applicable to new or existing structures. The schematic is based upon the design of a low-cost solar home heating system built and tested by NASA's Langley Research Center; used to supplement a warm-air heating system, it can save the homeowner about 40 percent of his annual heating bill for a modest investment in materials and components. Home Building Plan Service saved considerable research time by obtaining a NASA technical report which details the Langley work. The resulting schematic includes construction plans and simplified explanations of solar heat collection, collectors and other components, passive heat factors, domestic hot water supply and how to work with local heating engineers.

  18. Effects of size-controlled TiO2 nanopowders synthesized by chemical vapor condensation process on conversion efficiency of dye-sensitized solar cells.

    PubMed

    Kim, Woo-Byoung; Lee, Jai-Sung

    2013-07-01

    To investigate the microstructural effects of the synthesized TiO2 nanopowders such as particle size, specific surface area, pore size and pore distributions for the application of an anode material of dye-sensitized solar cells (DSSC), size-controlled and well-dispersed TiO2 nanopowders were synthesized by chemical vapor condensation (CVC) process in the range of 800-1000 degreesC under a pressure of 50 mbar. The average particle size of synthesized TiO2 nanopowders was increased with increasing temperature from 13 nm for 800 degreesC, 15 nm for 900 degreesC and 26 nm. The specific surface area of synthesized nanoparticles were measured as 119.1 m2/g for 800 degreesC, 104.7 m2/g for 900 degreesC and 59.5 m2/g for 1000 degreesC, respectively. The conversion efficiency values (eta%) of DSSC with the synthesized TiO2 nanopowders at 800 degreesC, 900 degreesC, and 1000 degreesC were 2.59%, 5.96% and 3.66%, respectively. The highest conversion efficiency obtained in the 900 degreesC (5.96%) sample is thought to be attributable to homogeneous particle size and pore distributions, large specific surface area, and high transmittance in regions of dye absorption wavelength.

  19. Control of charge dynamics by blending ZnO nanoparticles with poly(3-hexylthiophene) for efficient hybrid ZnO nanorods/polymer solar cells

    NASA Astrophysics Data System (ADS)

    Ruankham, Pipat; Choopun, Supab; Sagawa, Takashi

    2015-10-01

    Photovoltaic performances of hybrid ZnO nanorods/polymer solar cells have been improved by controlling their charge dynamics through addition of ZnO nanoparticles into poly(3-hexylthiophene) (P3HT) photoactive layer. The inter-rod space of ZnO nanorod substrates is completely filled with the solution-processed ZnO nanoparticles/P3HT blends, forming homogeneous junction among the components. The optimum PCE of 1.020 % has been achieved from the device with 13 vol % ZnO nanoparticles loaded. The enhancement in external quantum efficiency has been also observed, indicating the improved excitons separation at the ZnO/P3HT interface. The information on charge dynamics in the system has been investigated by electrochemical impedance spectroscopy. It has been found that the additional space-charge layer formed at the ZnO nanoparticles-contact electrode interface is a reason behind the improvement of open-circuit voltage. Moreover, the formation of ZnO nanoparticles domain extending across the active layer and the percolation path for charge carriers promotes charge transport by reducing transit time of the carriers, extending charge carrier lifetime and enhancing the charge transfer at the ZnO/P3HT interface. Interestingly, it has been found that charge transport in the devices does not limit the device performances, even for the 400-nm-thick active layer.

  20. Morphology-controlled cactus-like branched anatase TiO2 arrays with high light-harvesting efficiency for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Wu, Wu-Qiang; Rao, Hua-Shang; Feng, Hao-Lin; Guo, Xin-Dong; Su, Cheng-Yong; Kuang, Dai-Bin

    2014-08-01

    The present work establishes a facile process for one-step hydrothermal growth of vertically aligned anatase cactus-like branched TiO2 (CBT) arrays on a transparent conducting oxide (TCO) substrate. Various CBT morphologies are obtained by adjusting the potassium titanium oxide oxalate (PTO) reactant concentration (from 0.05 M to 0.15 M) and this yields a morphologically-controllable branched TiO2 arrays geometry. The CBT arrays consist of a vertically oriented nanowire (NW) or nanosheet (NS) stem and a host of short nanorod (NR) branches. The hierarchical CBT arrays demonstrate their excellent candidatures as photoanodes, which are capable of exhibiting high light-harvesting efficiency in dye-sensitized solar cells (DSSCs). Consequently, DSSCs based on 7 μm long optimized CBT arrays (0.05 M PTO), which are assembled with high density and high aspect-ratio NR branches, exhibit an impressive power conversion efficiency of 6.43% under AM 1.5G one sun illumination. The high performance can be attributed to the prominent light-harvesting efficiency, resulting from larger surface area and superior light-scattering capability.

  1. Stability and controllability of InGaAs/GaAsP wire-on-well (WoW) structure for multi-junction solar cells

    NASA Astrophysics Data System (ADS)

    Cho, Hirofumi; Toprasertpong, Kasidit; Sodabanlu, Hassanet; Watanabe, Kentaroh; Sugiyama, Masakazu; Nakano, Yoshiaki

    2017-04-01

    Wire on Well (WoW) structure embedded in a matrix is naturally formed by growing InxGa1-xAs/GaAs1-yPy strained multiple quantum wells (MQW) on vicinal substrates and employing triethylgallium (TEGa) as a precursor in low-temperature MOVPE. The structure is useful for the subcell in current-matched mult-junction solar cells with lattice-matched materials because of its ability of band-gap tuning. In this research, high density and uniform In0.30Ga0.70As/GaAs0.6P0.4 WoW was obtained up to 200 stacks and its structure was analyzed by X-ray diffraction reciprocal space mapping, atomic force microscopy and scanning transmission electron microscopy. The structure of the wire can be controlled by changing the equivalent layer thicknesses of In0.30Ga0.70As and GaAs0.6P0.4. The photoluminescence peak from the WoW shifted according to the size of InGaAs wires and the intensity was dependent on the accumulation of lattice-mismatch stress.

  2. Thickness-self-controlled synthesis of porous transparent polyaniline-reduced graphene oxide composites towards advanced bifacial dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Sheng; Li, Shin-Ming; Hsiao, Sheng-Tsung; Liao, Wei-Hao; Yang, Shin-Yi; Tien, Hsi-Wen; Ma, Chen-Chi M.; Hu, Chi-Chang

    2014-08-01

    A powerful synthesis strategy is proposed for fabricating porous polyaniline-reduced graphene oxide (PANI-RGO) composites with transparency up to 80% and thickness from 300 to 1000 nm for the counter electrode (CE) of bifacial dye-sensitizing solar cells (DSSCs). The first step is to combine the in-situ positive charge transformation of graphene oxide (GO) through aniline (ANI) prepolymerization and the electrostatic adsorption of ANI oligomer-GO to effectively control the thickness of ultrathin PANI-GO films by adjusting pH of the polymerization media. In the second step, PANI-GO films are reduced with hydroiodic acid to simultaneously enhance the apparent redox activity for the I3-/I- couple and their electronic conductivity. Incorporating the RGO increases the transparency of PANI and facilitates the light-harvesting from the rear side. A DSSC assembled with such a transparent PANI-RGO CE exhibits an excellent efficiency of 7.84%, comparable to 8.19% for a semi-transparent Pt-based DSSC. The high light-harvesting ability of PANI-RGO enhances the efficiency retention between rear- and front-illumination modes to 76.7%, compared with 69.1% for a PANI-based DSSC. The higher retention reduces the power-to-weight ratio and the total cost of bifacial DSSCs, which is also promising in other applications, such as windows, power generators, and panel screens.

  3. On the Cause of Solar Differential Rotations in the Solar Interior and Near the Solar Surface

    NASA Astrophysics Data System (ADS)

    Lyu, L.

    2012-12-01

    A theoretical model is proposed to explain the cause of solar differential rotations observed in the solar interior and near the solar surface. We propose that the latitudinal differential rotation in the solar convection zone is a manifestation of an easterly wind in the mid latitude. The speed of the easterly wind is controlled by the magnitude of the poleward temperature gradient in the lower part of the solar convection zone. The poleward temperature gradient depends on the orientation and strength of the magnetic fields at different latitudes in the solar convection zone. The north-south asymmetry in the wind speed can lead to north-south asymmetry in the evolution of the solar cycle. The easterly wind is known to be unstable for a west-to-east rotating star or planet. Based on the observed differential rotations in the solar convection zone, we can estimate the easterly wind speed at about 60-degree latitude and determine the azimuthal wave number of the unstable wave modes along the zonal flow. The lowest azimuthal wave number is about m=7~8. This result is consistent with the average width of the elephant-trunk coronal hole shown in the solar X-ray images. The nonlinear evolution of the unstable easterly wind can lead to transpolar migration of coronal holes and can change the poloidal magnetic field in a very efficient way. In the study of radial differential rotation near the solar surface, we propose that the radial differential rotation depends on the radial temperature gradient. The radial temperature gradient depends on the magnetic field structure above the solar surface. The non-uniform magnetic field distribution above the solar surface can lead to non-uniform radial convections and formation of magnetic flux rope at different spatial scales. The possible cause of continuous formation and eruption of prominences near an active region will also be discussed.

  4. SMART Solar Sail

    NASA Technical Reports Server (NTRS)

    Curtis, Steven A.

    2005-01-01

    A report summarizes the design concept of a super miniaturized autonomous reconfigurable technology (SMART) solar sail a proposed deployable, fully autonomous solar sail for use in very fine station keeping of a spacecraft. The SMART solar sail would include a reflective film stretched among nodes of a SMART space frame made partly of nanotubule struts. A microelectromechanical system (MEMS) at each vertex of the frame would spool and unspool nanotubule struts between itself and neighboring nodes to vary the shape of the frame. The MEMSs would be linked, either wirelessly or by thin wires within the struts, to an evolvable neural software system (ENSS) that would control the MEMSs to reconfigure the sail as needed. The solar sail would be highly deformable from an initially highly compressed configuration, yet also capable of enabling very fine maneuvering of the spacecraft by means of small sail-surface deformations. The SMART Solar Sail would be connected to the main body of the spacecraft by a SMART multi-tether structure, which would include MEMS actuators like those of the frame plus tethers in the form of longer versions of the struts in the frame.

  5. Molecular level control of nanoscale composition and morphology: Toward photocatalytic nanocomposites for solar-to-chemical energy conversion of biomass

    SciTech Connect

    Ruberu, Thanthrige P.

    2013-01-01

    Understanding the factors influencing nanocrystal formation is a challenge yet to be realized. In comparison to the large number of studies on nanocrystal synthesis and their applications, the number of studies on the effect of the precursor chemistry on nanocrystal composition and shape remains low. Although photochemical fabrication of metalsemiconductor nano-heterostructures is reported in literature, control over the free particle formation and the site of metal deposition have not been achieved. Moreover, utilization of metal- semiconductor nano-heterostructures in photocatalytic reactions other than water splitting is hardly explored. In this thesis, we studied the effect of chalcogenide precursor reactivity on the composition, morphology and the axial anisotropy of cadmiumchalcogenide nanocrystals. We also investigated the influence of the irradiation wavelength in synthesizing metal-semiconductor nano-heterostructures. Finally, we showed that metal semiconductor nano-heterostructures can be used as a photocatalyst for alcohol dehydrogenation reactions. We explored the pathways for the formation of Pt and Pd nanoparticles on CdS and CdS{sub 0.4}Se{sub 0.6} nanorods. This study revealed that the wavelength of irradiation is critical to control free-standing vs. bound metal (Pt and Pd) nanoparticles to semiconductor. Additionally, we observed that metal photodeposition occurs on specific segments of axially anisotropic, compositionally graded CdS0.4Se0.6 nanorods due to the band-gap differential between their nano-domains. We used semiconductor-metal heterostructures for sunlightdriven dehydrogenation and hydrogenolysis of benzyl alcohol. Heterostructure composition dictates activity (turnovers) and product distribution. A few metal (Pt, Pd) islands on the semiconductor surface significantly enhance activity and selectivity and also greatly stabilize the semiconductor against photoinduced etching and degradation.

  6. Actividad Solar Desde EL Espacio

    NASA Astrophysics Data System (ADS)

    Rovira, M. G.

    1990-11-01

    RESUMEN. Se describen los principales descubrimientos realizados por los arti+iciales con instrumentos dedicados a la observaci6n del Sol, durante los dos ultimos ciclos de su acti vi dad. La observaci6n el espacio ha permitido cubrir todas las zonas del espectro no observables desde tierra1 desde el ultravioleta hasta la radiaci6n gamma. Se hace referencia, en particular, a los resultados producidos por los dos grandes observatorios: el Skylab y el SMM. Este ultimo incluy6 un conjunto de instrumentos especialmente coordinados para observar en detalle las fulguraciones solares. Es un resumen para astr6nomos no especializados en la fisica solar, en el que se muestra que la gran riqueza del material observacional acumulado ha resuelto problemas preexistentes y, al mismo tiempo, ha abierto numerosos interrogantes a los que se buscar respuesta con la instrumentaci6n en desarrollo. Finalmente, se mencionan las caracteristicas de los proyectados para la pr6xima decada. : The main discoveries performed by artificial satellites instrumented for the observation of the Sun, during the last two cycles of its activity, are described. The space observations allowed of almost all the spectral regions which are not observable from the ground, from the ultraviolet to the gamma radiation. In particular, we ref er' to the two large solar space observatories: the Skylab and the SMM. The last one included a set 0+ coordinated instruments to observe in detail the solar flares. This is a summary for astronomers not dedicated to solar physics, where we show that the of observational material have solv# d many of the preexistent problems but, at the ame time, it opened many new questions to which the improved instrumentation will try to answer. , the characteristics of the satellites planned the next decade are mentioned. Key : SUN-ACTIVITY - SUN-CORONA - SUN-X-RAYS

  7. The LEO Archipelago: A system of earth-rings for communications, mass-transport to space, solar power, and control of global warming

    NASA Astrophysics Data System (ADS)

    Meulenberg, Andrew; Karthik Balaji, P. S.

    2011-06-01

    Man's quest to get into space is hindered by major problems (e.g., system-development and capital costs, expense of putting mass into orbit, trapped-radiation belts, and environmental impact of a large increase in rocket launches). A multi-purpose low-earth-orbit system of rings circling the earth - the "LEO ARCHIPELAGO TM" - is proposed as a means of solving or bypassing many of them. A fiber-optic ring about the earth would be an initial testing and developmental stage for the Ring Systems, while providing cash-flow through a LEO-based, high-band-width, world-wide communication system. A low-earth-orbit-based space-elevator system, "Sling-on-a-Ring TM", is proposed as the crucial developmental stage of the LEO Archipelago. Being a LEO-based heavy-mass lifter, rather than earth- or GEO-based, it is much less massive and therefore less costly than other proposed space-elevators. With the advent of lower-cost, higher-mass transport to orbit, the options for further space development (e.g., space solar power, radiation, and space-debris dampers, sun shades, and permanent LEO habitation) are greatly expanded. This paper provides an update of the Sling-on-a-Ring concept in terms of new materials, potential applications, and trade-offs associated with an earlier model. The impact of Colossal Carbon Tubes, CCT, a new material with high tensile strength, extremely-low density, and other favorable properties, and other new technologies (e.g., solar-powered lasers, power beaming to near-space and earth, and thermal-control systems) on the development of associated LEO-Ring systems is also explored. The material's effect on the timeline for the system development indicates the feasibility of near-term implementation of the system (possibly within the decade). The Sling-on-a-Ring can provide a less-expensive, environment-friendly mode of access to space. This would pave the way (via eventual operation at >1000 t per day by 2050) for large scale development of space

  8. Fine control of perovskite-layered morphology and composition via sequential deposition crystallization process towards improved perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Luo, Yi; Meng, Fanli; Zhao, Erfei; Zheng, Yan-Zhen; Zhou, Yali; Tao, Xia

    2016-04-01

    The ability to prepare high coverage and compact perovskite films via solution-based crystallization manipulation processes still represents a vital issue towards improving the ultimate photoelectric conversion efficiency of devices. In this work, we prepare the active perovskite layer by means of sequential deposition crystallization process i.e. dipping PbI2-infiltrated TiO2 film within CH3NH3I solution from 20s to 60s. The morphology and thickness of the as-prepared perovskite layer, and its overall performance superiority are investigated. X-ray diffraction (XRD) reveals that a maximum conversion of PbI2 to perovskite is completed upon applying a sequential deposition crystallization process of 40s. Field emission scanning electron microscope (FESEM) demonstrates that the coverage of the perovskite capping layer exhibits a trend from rise to decline in the whole dipping time from 20s to 60s. By fine control of the dipping time, a 620 nm-thickness compact perovskite active layer is obtained at the optimized dipping time of 40s and is verified to possess strong light absorption and high electron extraction efficiency, leading to a higher photocurrent. By further optimizing the mesoporous TiO2 film thickness, a high photocurrent of 23.98 mA cm-2 and an efficiency of 13.47% are achieved.

  9. Particle shape inhomogeneity and plasmon-band broadening of solar-control LaB{sub 6} nanoparticles

    SciTech Connect

    Machida, Keisuke; Adachi, Kenji

    2015-07-07

    An ensemble inhomogeneity of non-spherical LaB{sub 6} nanoparticles dispersion has been analyzed with Mie theory to account for the observed broad plasmon band. LaB{sub 6} particle shape has been characterized using small-angle X-ray scattering (SAXS) and electron tomography (ET). SAXS scattering intensity is found to vary exponentially with exponent −3.10, indicating the particle shape of disk toward sphere. ET analysis disclosed dually grouped distribution of nanoparticle dispersion; one is large-sized at small aspect ratio and the other is small-sized with scattered high aspect ratio, reflecting the dual fragmentation modes during the milling process. Mie extinction calculations have been integrated for 100 000 particles of varying aspect ratio, which were produced randomly by using the Box-Muller method. The Mie integration method has produced a broad and smooth absorption band expanded towards low energy, in remarkable agreement with experimental profiles by assuming a SAXS- and ET-derived shape distribution, i.e., a majority of disks with a little incorporation of rods and spheres for the ensemble. The analysis envisages a high potential of LaB{sub 6} with further-increased visible transparency and plasmon peak upon controlled particle-shape and its distribution.

  10. High Performance Perovskite Solar Cells.

    PubMed

    Tong, Xin; Lin, Feng; Wu, Jiang; Wang, Zhiming M

    2016-05-01

    Perovskite solar cells fabricated from organometal halide light harvesters have captured significant attention due to their tremendously low device costs as well as unprecedented rapid progress on power conversion efficiency (PCE). A certified PCE of 20.1% was achieved in late 2014 following the first study of long-term stable all-solid-state perovskite solar cell with a PCE of 9.7% in 2012, showing their promising potential towards future cost-effective and high performance solar cells. Here, notable achievements of primary device configuration involving perovskite layer, hole-transporting materials (HTMs) and electron-transporting materials (ETMs) are reviewed. Numerous strategies for enhancing photovoltaic parameters of perovskite solar cells, including morphology and crystallization control of perovskite layer, HTMs design and ETMs modifications are discussed in detail. In addition, perovskite solar cells outside of HTMs and ETMs are mentioned as well, providing guidelines for further simplification of device processing and hence cost reduction.

  11. High Performance Perovskite Solar Cells

    PubMed Central

    Tong, Xin; Lin, Feng; Wu, Jiang

    2015-01-01

    Perovskite solar cells fabricated from organometal halide light harvesters have captured significant attention due to their tremendously low device costs as well as unprecedented rapid progress on power conversion efficiency (PCE). A certified PCE of 20.1% was achieved in late 2014 following the first study of long‐term stable all‐solid‐state perovskite solar cell with a PCE of 9.7% in 2012, showing their promising potential towards future cost‐effective and high performance solar cells. Here, notable achievements of primary device configuration involving perovskite layer, hole‐transporting materials (HTMs) and electron‐transporting materials (ETMs) are reviewed. Numerous strategies for enhancing photovoltaic parameters of perovskite solar cells, including morphology and crystallization control of perovskite layer, HTMs design and ETMs modifications are discussed in detail. In addition, perovskite solar cells outside of HTMs and ETMs are mentioned as well, providing guidelines for further simplification of device processing and hence cost reduction. PMID:27774402

  12. Installation package for a domestic solar heating and hot water system

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The installation of two prototype solar heating and hot water systems is described. The systems consists of the following subsystems: solar collector, storage, control, transport, and auxiliary energy.

  13. Maximum collectible solar energy by different solar tracking systems

    SciTech Connect

    Helwa, N.H.; Bahgat, A.B.G.; El Shafee, A.M.R.; El Shenawy, E.T.

    2000-01-01

    The output energy from any solar energy system depends on the solar energy input to that system. Using different ways to track the solar energy system to follow the sun can increase solar energy input according to the type of the tracker. A practical study was carried out on difference solar tract systems. The layout of these systems are a fixed system facing south and tilted 40{degree}, a vertical-axis tracker, a 6{degree} tilted-axis tracker, and a two-axis tracker. All the trackers are microprocessor controlled systems, and all systems have photovoltaic arrays for electric energy production. The evaluation of the different systems is based on a complete year of measurements for solar radiation input to the systems and the electric power output from them. The study also includes the effect of some operating parameters on the tracker operation. These studies showed that the collected solar energy as well as the electrical output energy of the tracking solar system are more than that of the stationary system. These gains are higher in the case of the two-axis tracker and decrease gradually from the vertical-axis tracker to the tilted-axis tracker.

  14. ¡Cocinar Para Su Salud!: Randomized controlled trial of a culturally-based dietary intervention among Hispanic breast cancer survivors

    PubMed Central

    Greenlee, Heather; Gaffney, Ann Ogden; Aycinena, A. Corina; Koch, Pam; Contento, Isobel; Karmally, Wahida; Richardson, John M.; Lim, Emerson; Tsai, Wei-Yann; Crew, Katherine; Maurer, Matthew; Kalinsky, Kevin; Hershman, Dawn L.

    2015-01-01

    BACKGROUND There is a need for culturally-relevant nutrition programs targeted to underserved cancer survivors. OBJECTIVE To examine the effect of a culturally-based approach to dietary change on increasing fruit/vegetable intake and decreasing fat intake among Hispanic breast cancer (BC) survivors. DESIGN Participants were randomized to intervention (IG) and control (CG) groups. Diet recalls, detailed interviews, fasting blood, and anthropometric measures were collected at baseline, 3-, 6- and 12-months. PARTICIPANTS/SETTING Hispanic women (n=70) with stage 0-III BC who completed adjuvant treatment and lived in New York City were randomized between April 2011 and March 2012. INTERVENTION The IG (n=34) participated in ¡Cocinar Para Su Salud! (¡CPSS!), a culturally-based 9-session (24-hours over 12 weeks) intervention including nutrition education, cooking classes and food shopping field trips. The CG (n=36) received written dietary recommendations for BC survivors. MAIN OUTCOME MEASURES Change at 6 months in daily fruit/vegetable servings and % calories from total fat. STATISTICAL ANALYSES Linear regression models adjusted for stratification factors and estimated marginal means were used to compare changes in diet from baseline to 3- and 6-months. RESULTS Baseline characteristics: mean age 56.6 years (SD 9.7), mean time since diagnosis 3.4 years (SD 2.7), mean BMI 30.9 kg/m2 (SD 6.0), 62.9% with annual household income ≤$15,000, average daily servings of all fruits/vegetables 5.3 (targeted fruits/vegetables 3.7 servings excluding legumes/juices/starchy vegetables/fried foods) and 27.7% of daily calories from fat. Over 60% in the IG attended ≥7/9 classes with overall study retention of 87% retention at 6 months. At month 6, the IG compared to CG reported an increase in mean servings of fruits/vegetables from baseline (all fruits/vegetables: +2.0 vs. −0.1, P=0.005; targeted fruits/vegetables: +2.7 vs. +0.5, P=0.002) and a non-significant decrease in

  15. ISS Solar Array Management

    NASA Technical Reports Server (NTRS)

    Williams, James P.; Martin, Keith D.; Thomas, Justin R.; Caro, Samuel

    2010-01-01

    The International Space Station (ISS) Solar Array Management (SAM) software toolset provides the capabilities necessary to operate a spacecraft with complex solar array constraints. It monitors spacecraft telemetry and provides interpretations of solar array constraint data in an intuitive manner. The toolset provides extensive situational awareness to ensure mission success by analyzing power generation needs, array motion constraints, and structural loading situations. The software suite consists of several components including samCS (constraint set selector), samShadyTimers (array shadowing timers), samWin (visualization GUI), samLock (array motion constraint computation), and samJet (attitude control system configuration selector). It provides high availability and uptime for extended and continuous mission support. It is able to support two-degrees-of-freedom (DOF) array positioning and supports up to ten simultaneous constraints with intuitive 1D and 2D decision support visualizations of constraint data. Display synchronization is enabled across a networked control center and multiple methods for constraint data interpolation are supported. Use of this software toolset increases flight safety, reduces mission support effort, optimizes solar array operation for achieving mission goals, and has run for weeks at a time without issues. The SAM toolset is currently used in ISS real-time mission operations.

  16. Solar ponds

    NASA Astrophysics Data System (ADS)

    Tabor, H.

    1981-01-01

    The history and current status of salt-gradient non-convecting solar ponds are presented. These ponds are large-area collectors, capable of providing low-cost thermal, mechanical, or electrical energy using low-temperature turbo-generators. The basic theory of salt-gradient solar ponds is sketched; the effects of wind, leakage, and fouling and their constraints on location selection for solar ponds are discussed. The methods of building and filling the ponds, as well as extracting heat from them are explained in detail. Practical operating temperatures of 90 C can be obtained with collection efficiencies between 15% and 25%, demonstrating the practical use of the ponds for heating and cooling purposes, power production, and desalination. A condensed account of solar pond experience in several countries is given. This includes the 150 kW solar pond power station (SPPS) operating in Israel since December, 1979 and a 5000 kW unit currently under development. A study of the economics involved in using the ponds is presented: despite a low conversion efficiency, the SPPS is shown to have applications in many countries.

  17. Design of a Traditional Solar Tracking System

    NASA Astrophysics Data System (ADS)

    Barsoum, Nader; Vasant, Pandian

    2010-06-01

    Solar energy is rapidly advancing as an important means of renewable energy resource. More energy is produced by tracking the solar panel to remain aligned to the sun at a right angle to the rays of light. This paper describes in detail the design and construction of a prototype for solar tracking system with two degrees of freedom, which detects the sunlight using photocells. The control circuit for the solar tracker is based on a PIC16F84A microcontroller (MCU). This is programmed to detect the sunlight through the photocells and then actuate the motor to position the solar panel where it can receive maximum sunlight.

  18. The solar wind-magnetosphere-ionosphere system

    PubMed

    Lyon

    2000-06-16

    The solar wind, magnetosphere, and ionosphere form a single system driven by the transfer of energy and momentum from the solar wind to the magnetosphere and ionosphere. Variations in the solar wind can lead to disruptions of space- and ground-based systems caused by enhanced currents flowing into the ionosphere and increased radiation in the near-Earth environment. The coupling between the solar wind and the magnetosphere is mediated and controlled by the magnetic field in the solar wind through the process of magnetic reconnection. Understanding of the global behavior of this system has improved markedly in the recent past from coordinated observations with a constellation of satellite and ground instruments.

  19. Solar ADEPT: Efficient Solar Energy Systems

    SciTech Connect

    2011-01-01

    Solar ADEPT Project: The 7 projects that make up ARPA-E's Solar ADEPT program, short for 'Solar Agile Delivery of Electrical Power Technology,' aim to improve the performance of photovoltaic (PV) solar energy systems, which convert the sun's rays into electricity. Solar ADEPT projects are integrating advanced electrical components into PV systems to make the process of converting solar energy to electricity more efficient.

  20. Solar Minimum

    NASA Astrophysics Data System (ADS)

    Lopresto, James C.; Mathews, John; Manross, Kevin

    1995-12-01

    Calcium K plage, H alpha plage and sunspot area have been monitored daily on the INTERNET since November of 1992. The plage and sunspot area have been measured by image processing. The purpose of the project is to investigate the degree of correlation between plage area and solar irradiance. The plage variation shows the expected variation produced by solar rotation and the longer secular changes produced by the solar cycle. The H alpha and sunspot plage area reached a minimum in about late 1994 or early 1995. This is in agreement with the K2 spectral index obtained daily from Sacramento Peak Observatory. The Calcium K plage area minimum seems delayed with respect to the others mentioned above. The minimum of the K line plage area is projected to come within the last few months of 1995.

  1. Solar Neutrinos

    DOE R&D Accomplishments Database

    Davis, R. Jr.; Harmer, D. S.

    1964-12-01

    The prospect of studying the solar energy generation process directly by observing the solar neutrino radiation has been discussed for many years. The main difficulty with this approach is that the sun emits predominantly low energy neutrinos, and detectors for observing low fluxes of low energy neutrinos have not been developed. However, experimental techniques have been developed for observing neutrinos, and one can foresee that in the near future these techniques will be improved sufficiently in sensitivity to observe solar neutrinos. At the present several experiments are being designed and hopefully will be operating in the next year or so. We will discuss an experiment based upon a neutrino capture reaction that is the inverse of the electron-capture radioactive decay of argon-37. The method depends upon exposing a large volume of a chlorine compound, removing the radioactive argon-37 and observing the characteristic decay in a small low-level counter.

  2. Solar flare particle radiation

    NASA Technical Reports Server (NTRS)

    Lanzerotti, L. J.

    1972-01-01

    The characteristics of the solar particles accelerated by solar flares and subsequently observed near the orbit of the earth are studied. Considered are solar particle intensity-time profiles, the composition and spectra of solar flare events, and the propagation of solar particles in interplanetary space. The effects of solar particles at the earth, riometer observations of polar cap cosmic noise absorption events, and the production of solar cell damage at synchronous altitudes by solar protons are also discussed.

  3. The Controlling Mechanism for Potential Loss in CH 3 NH 3 PbBr 3 Hybrid Solar Cells

    SciTech Connect

    Zheng, Xiaojia; Chen, Bo; Yang, Mengjin; Wu, Congcong; Orler, Bruce; Moore, Robert B.; Zhu, Kai; Priya, Shashank

    2016-08-12

    We investigated moisture and thermal stability of MAPbBr3 perovskite material. Cubic MAPbBr3 was found to be moisture-insensitive and can avoid the thermal stability issues introduced by low-temperature phase transition in MAPbI3. MAPbBr3 and MAPbI3 hybrid solar cells with efficiencies of ~7.1% and ~15.5%, respectively, were fabricated, and we identified the correlation between the working temperature, light intensity, and the photovoltaic performance. No charge-carrier transport barriers were found in the MAPbBr3 and MAPbI3 solar cells. The MAPbBr3 solar cell displays a better stability under high working temperature because of its close-packed crystal structure. Temperature-dependent photocurrent-voltage characteristics indicate that, unlike the MAPbI3 solar cell with an activation energy (EA) nearly equal to its band gap (Eg), the EA for the MAPbBr3 solar cell is much lower than its Eg. This indicates that a high interface recombination process limits the photovoltage and consequently the device performance of the MAPbBr3 solar cell.

  4. Solar panel

    SciTech Connect

    Bayles, B.R.

    1981-09-29

    A solar panel includes a base within which are mounted transversely extending conduits. A heat collector plate in the base is in heat conductive relationship with the conduits for the heating of a fluid medium. The base additionally supports a transparent cover outwardly spaced from the heat collector plate to provide a protective insulative air space over the plate. A manifold communicates one series of panels with those of an adjacent series. A modified base dispenses with a collector plate and is formed so as to define integral lengthwise extending passageways for the solar heated medium. Inserted nipples interconnect the passageways of adjacent panels.

  5. Solar trap

    SciTech Connect

    Lew, H.S.

    1988-02-09

    A solar trap for collecting solar energy at a concentrated level is described comprising: (a) a compound light funnel including a pair of light reflecting substantially planar members arranged into a trough having a substantially V-shaped cross section; (b) a two dimensional Fresnel lens cover covering the opening of the compound light funnel, the opening being the open diverging end of the substantially V-shaped cross section of the compound light funnel; (c) at least one conduit for carrying a heat transfer fluid disposed substantially adjacent and substantially parallel to the apex line of the compound light funnel.

  6. Solar Energy and You.

    ERIC Educational Resources Information Center

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    This booklet provides an introduction to solar energy by discussing: (1) how a home is heated; (2) how solar energy can help in the heating process; (3) the characteristics of passive solar houses; (4) the characteristics of active solar houses; (5) how solar heat is stored; and (6) other uses of solar energy. Also provided are 10 questions to…

  7. Solar maximum: Solar array degradation

    NASA Technical Reports Server (NTRS)

    Miller, T.

    1985-01-01

    The 5-year in-orbit power degradation of the silicon solar array aboard the Solar Maximum Satellite was evaluated. This was the first spacecraft to use Teflon R FEP as a coverglass adhesive, thus avoiding the necessity of an ultraviolet filter. The peak power tracking mode of the power regulator unit was employed to ensure consistent maximum power comparisons. Telemetry was normalized to account for the effects of illumination intensity, charged particle irradiation dosage, and solar array temperature. Reference conditions of 1.0 solar constant at air mass zero and 301 K (28 C) were used as a basis for normalization. Beginning-of-life array power was 2230 watts. Currently, the array output is 1830 watts. This corresponds to a 16 percent loss in array performance over 5 years. Comparison of Solar Maximum Telemetry and predicted power levels indicate that array output is 2 percent less than predictions based on an annual 1.0 MeV equivalent election fluence of 2.34 x ten to the 13th power square centimeters space environment.

  8. Biomolecule-controlled hydrothermal synthesis of C-N-S-tridoped TiO2 nanocrystalline photocatalysts for NO removal under simulated solar light irradiation.

    PubMed

    Wang, Yawen; Huang, Yu; Ho, Wingkei; Zhang, Lizhi; Zou, Zhigang; Lee, Shuncheng

    2009-09-30

    In this study, C-N-S-tridoped titanium dioxide (TiO(2)) nanocrystals were synthesized by using a facile hydrothermal method in the presence of a biomolecule l-cysteine. This biomolecule could not only serve as the common source for the carbon, sulfur and nitrogen tridoping, but also could control the final crystal phases and morphology. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption and UV-vis diffuse reflectance spectroscopy. XPS analysis revealed that S was incorporated into the lattice of TiO(2) through substituting oxygen atoms, N might coexist in the forms of N-Ti-O and Ti-O-N in tridoped TiO(2) and most C could form a mixed layer of carbonate species deposited on the surface of TiO(2) nanoparticles. The photocatalytic activities of the samples were tested on the removal of NO at typical indoor air level in a flow system under simulated solar light irradiation. The tridoped TiO(2) samples showed much higher removal efficiency than commercial P25 and the undoped counterpart photocatalyst. The enhanced visible light photocatalytic activity of C-N-S-tridoped TiO(2) nanocrystals was explained on the basis of characterizations. The possible formation process of the monodispersed C-N-S-tridoped anatase TiO(2) nanocrystals was also proposed. This study provides a new method to prepare visible light active TiO(2) photocatalyst.

  9. Telescopio Solar en Hα (HASTA)

    NASA Astrophysics Data System (ADS)

    Fernández Borda, R.; Francile, C.; Bagala, G.; Bauer, O.; Haerendel, G.; Rieger, E.; Rovira, M.

    El Telescopio Solar en Hα (Hα Solar Telescope for Argentina (-HASTA-) fue recientemente instalado en la Estación Astronómica de Altura Carlos Ulrrico Cesco (OAFA) en El Leoncito. Este instrumento estudiará la evolución de las fulguraciones solares desde tierra con alta resolución temporal y espacial. HASTA es un telescopio refractor de 110 mm con una distancia focal de 165 cm, un filtro Lyot sintonizable (±1Å) con un ancho de banda de 0.3 Å y una cámara CCD de alta resolución (1280×1024 pixels). Todo el conjunto es controlado en forma remota por una PC, la cual además adquiere datos del Sistema de Posicionamiento Global (GPS) y de la estación meteorológica. Diseñado para detectar fulguraciones, el instrumento trabaja en dos modos (patrullaje y fulguración) con una resolución espacial de 1.5 arcseg por pixel y una resolución temporal de 2 seg. HASTA comenzó a operar en Mayo de 1998 y, junto con otros tres instrumentos solares, que se están instalando o se instalaron, harán de El Leoncito un polo de observación solar importante en el Hemisferio Sur.

  10. Solar Power

    ERIC Educational Resources Information Center

    Ford, Norman C.; Kane, Joseph W.

    1971-01-01

    Proposes a method of collecting solar energy by using available plastics for Fresnel lenses to focus heat onto a converter where thermal dissociation of water would produce hydrogen. The hydrogen would be used as an efficient non-polluting fuel. Cost estimates are included. (AL)

  11. Solar Directory.

    ERIC Educational Resources Information Center

    Pesko, Carolyn, Ed.

    This directory is designed to help the researcher and developer, the manufacturer and distributor, and the general public communicate together on a mutually beneficial basis. Its content covers the wide scope of solar energy activity in the United States primarily, but also in other countries, at the academic, governmental, and industrial levels.…

  12. Solar cooker

    SciTech Connect

    Long, J. B.; Ware, R. R.

    1985-12-31

    A solar cooking device made of a flat array of concentric mirrors tilted to focus at a small area, the array being movable mounted on a stand to be movable around a ball joint and with a carrier for a cooking vessel held by a double crank to be at the focal area of the mirrors.

  13. Solar heat receiver

    DOEpatents

    Hunt, A.J.; Hansen, L.J.; Evans, D.B.

    1982-09-29

    A receiver is described for converting solar energy to heat a gas to temperatures from 700 to 900/sup 0/C. The receiver is formed to minimize impingement of radiation on the walls and to provide maximum heating at and near the entry of the gas exit. Also, the receiver is formed to provide controlled movement of the gas to be heated to minimize wall temperatures. The receiver is designed for use with gas containing fine heat absorbing particles, such as carbon particles.

  14. Solar heat receiver

    DOEpatents

    Hunt, Arlon J.; Hansen, Leif J.; Evans, David B.

    1985-01-01

    A receiver for converting solar energy to heat a gas to temperatures from 700.degree.-900.degree. C. The receiver is formed to minimize impingement of radiation on the walls and to provide maximum heating at and near the entry of the gas exit. Also, the receiver is formed to provide controlled movement of the gas to be heated to minimize wall temperatures. The receiver is designed for use with gas containing fine heat absorbing particles, such as carbon particles.

  15. Interface control of semiconducting metal oxide layers for efficient and stable inverted polymer solar cells with open-circuit voltages over 1.0 volt.

    PubMed

    Yin, Zhigang; Zheng, Qingdong; Chen, Shan-Ci; Cai, Dongdong

    2013-09-25

    Inverted polymer solar cells (PSCs) with high open-circuit voltages of 1.00-1.06 V are fabricated by using an indenofluorene-containing copolymer (PIFTBT8) as an electron donor material and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an electron acceptor material. To improve the photovoltaic performance, interface control of various low-temperature processed ZnO films as cathode buffer layers is systematically investigated for effective electron transportation, while transition metal oxides including MoO3, WO3, NiO, and Cu2O are employed as anode buffer layers for hole-extraction. Incorporation of optimized semiconducting metal oxide interlayers can minimize interfacial power losses, which thus affords large open-circuit voltages (Voc), increased short-circuit current densities (Jsc), and fill factors (FF), eventually contributing to higher power conversion efficiencies (PCEs) as well as better device stability. Due to the improved interfacial contacts and fine-matching energy levels, inverted PSCs with a device configuration of ITO/ZnO/PIFTBT8:PC71BM/MoO3/Ag exhibit a high PCE of 5.05% with a large Voc of 1.04 V, a Jsc of 9.74 mA cm(-2), and an FF of 50.1%. For the single junction inverted PSCs with efficiencies over 5.0%, 1.04 V is the largest Voc ever achieved. By controlling the processing conditions of the active layer, the Voc can further be improved to 1.05 and 1.06 V, with PCEs of 4.70% and 4.18%, respectively. More importantly, the inverted PSCs are ascertained to maintain a PCE of 4.55% (>90% of its initial efficiency) and a Voc of 1.05 V over 180 days, demonstrating good long-term stability, which is much better than that of the conventional devices. The results suggest that the interface engineering of metal oxide interlayers is an important strategy to develop PSCs with good performance.

  16. Solar Sail Model Validation from Echo Trajectories

    NASA Technical Reports Server (NTRS)

    Heaton, Andrew F.; Brickerhoff, Adam T.

    2007-01-01

    The NASA In-Space Propulsion program has been engaged in a project to increase the technology readiness of solar sails. Recently, these efforts came to fruition in the form of several software tools to model solar sail guidance, navigation and control. Furthermore, solar sails are one of five technologies competing for the New Millennium Program Space Technology 9 flight demonstration mission. The historic Echo 1 and Echo 2 balloons were comprised of aluminized Mylar, which is the near-term material of choice for solar sails. Both spacecraft, but particularly Echo 2, were in low Earth orbits with characteristics similar to the proposed Space Technology 9 orbit. Therefore, the Echo balloons are excellent test cases for solar sail model validation. We present the results of studies of Echo trajectories that validate solar sail models of optics, solar radiation pressure, shape and low-thrust orbital dynamics.

  17. Characterizing the Solar Wind at L1

    NASA Astrophysics Data System (ADS)

    Jahn, J.; Elliott, H. A.

    2008-12-01

    The nature of solar wind-magnetosphere energy transfer plays a big role in understanding the time history and types of global-scale magnetospheric phenomena. However, systematic approaches to quantifying how the specific magnetospheric "modes" (if they can be called that) of substorms, SMCs, sawtooth events, and geomagnetic storms could be controlled by the solar wind are still difficult. We present a fresh approach to characterizing the solar wind and its time history using self-organizing maps. The thrust of this effort is geared towards detecting and classifying solar wind structure on time scales relevant for the magnetospheric responses of interest. Performing this characterization at the L1 point is ideal for uncovering solar wind- magnetosphere relationships. It also provides a very long, contiguous time series that helps us explore these relationships over a complete solar cycle. We present the technique and initial results of solar wind comparisons during and leading up to SMCs and sawtooth events.

  18. Solar electric systems

    SciTech Connect

    Warfield, G.

    1984-01-01

    Electricity from solar sources is the subject. The state-of-the-art of photovoltaics, wind energy and solar thermal electric systems is presented and also a broad range of solar energy activities throughout the Arab world is covered. Contents, abridged: Solar radiation fundamentals. Basic theory solar cells. Solar thermal power plants. Solar energy activities at the scientific research council in Iraq. Solar energy program at Kuwait Institute for Scientific Research. Prospects of solar energy for Egypt. Non-conventional energy in Syria. Wind and solar energies in Sudan. Index.

  19. Solar Powered Refrigeration System

    NASA Technical Reports Server (NTRS)

    Ewert, Michael K. (Inventor); Bergeron, David J., III (Inventor)

    2002-01-01

    A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.

  20. Solar Powered Refrigeration System

    NASA Astrophysics Data System (ADS)

    Ewert, Michael K.; Bergeron, David J., III

    2002-09-01

    A solar powered vapor compression refrigeration system is made practicable with thermal storage and novel control techniques. In one embodiment, the refrigeration system includes a photovoltaic panel, a variable speed compressor, an insulated enclosure, and a thermal reservoir. The photovoltaic (PV) panel converts sunlight into DC (direct current) electrical power. The DC electrical power drives a compressor that circulates refrigerant through a vapor compression refrigeration loop to extract heat from the insulated enclosure. The thermal reservoir is situated inside the insulated enclosure and includes a phase change material. As heat is extracted from the insulated enclosure, the phase change material is frozen, and thereafter is able to act as a heat sink to maintain the temperature of the insulated enclosure in the absence of sunlight. The conversion of solar power into stored thermal energy is optimized by a compressor control method that effectively maximizes the compressor's usage of available energy. A capacitor is provided to smooth the power voltage and to provide additional current during compressor start-up. A controller monitors the rate of change of the smoothed power voltage to determine if the compressor is operating below or above the available power maximum, and adjusts the compressor speed accordingly. In this manner, the compressor operation is adjusted to convert substantially all available solar power into stored thermal energy.