Heating, Ventilation and Air-Conditioning Systems, Part of Indoor Air Quality Design Tools for Schools

EPA Pesticide Factsheets

The main purposes of a Heating, Ventilation, and Air-Conditioning system are to help maintain good indoor air quality through adequate ventilation with filtration and provide thermal comfort. HVAC systems are among the largest energy consumers in schools.

The microbiological quality of air improves when using air conditioning systems in cars.

PubMed

Vonberg, Ralf-Peter; Gastmeier, Petra; Kenneweg, Björn; Holdack-Janssen, Hinrich; Sohr, Dorit; Chaberny, Iris F

2010-06-01

Because of better comfort, air conditioning systems are a common feature in automobiles these days. However, its impact on the number of particles and microorganisms inside the vehicle--and by this its impact on the risk of an allergic reaction--is yet unknown. Over a time period of 30 months, the quality of air was investigated in three different types of cars (VW Passat, VW Polo FSI, Seat Alhambra) that were all equipped with a automatic air conditioning system. Operation modes using fresh air from outside the car as well as circulating air from inside the car were examined. The total number of microorganisms and the number of mold spores were measured by impaction in a high flow air sampler. Particles of 0.5 to 5.0 microm diameter were counted by a laser particle counter device. Overall 32 occasions of sampling were performed. The concentration of microorganisms outside the cars was always higher than it was inside the cars. Few minutes after starting the air conditioning system the total number of microorganisms was reduced by 81.7%, the number of mold spores was reduced by 83.3%, and the number of particles was reduced by 87.8%. There were no significant differences neither between the types of cars nor between the types of operation mode of the air conditioning system (fresh air vs. circulating air). All parameters that were looked for in this study improved during utilization of the car's air conditioning system. We believe that the risk of an allergic reaction will be reduced during use also. Nevertheless, we recommend regular maintenance of the system and replacement of older filters after defined changing intervals.

The microbiological quality of air improves when using air conditioning systems in cars

PubMed Central

2010-01-01

Background Because of better comfort, air conditioning systems are a common feature in automobiles these days. However, its impact on the number of particles and microorganisms inside the vehicle - and by this its impact on the risk of an allergic reaction - is yet unknown. Methods Over a time period of 30 months, the quality of air was investigated in three different types of cars (VW Passat, VW Polo FSI, Seat Alhambra) that were all equipped with a automatic air conditioning system. Operation modes using fresh air from outside the car as well as circulating air from inside the car were examined. The total number of microorganisms and the number of mold spores were measured by impaction in a high flow air sampler. Particles of 0.5 to 5.0 μm diameter were counted by a laser particle counter device. Results Overall 32 occasions of sampling were performed. The concentration of microorganisms outside the cars was always higher than it was inside the cars. Few minutes after starting the air conditioning system the total number of microorganisms was reduced by 81.7%, the number of mold spores was reduced by 83.3%, and the number of particles was reduced by 87.8%. There were no significant differences neither between the types of cars nor between the types of operation mode of the air conditioning system (fresh air vs. circulating air). All parameters that were looked for in this study improved during utilization of the car's air conditioning system. Conclusions We believe that the risk of an allergic reaction will be reduced during use also. Nevertheless, we recommend regular maintenance of the system and replacement of older filters after defined changing intervals. PMID:20515449

Application of solar energy to air-conditioning

NASA Technical Reports Server (NTRS)

Harstad, A. J.; Nash, J. M.

1978-01-01

Results of survey of application of solar energy to air-conditioning systems are summarized in report. Survey reviewed air-conditioning techniques that are most likely to find residential applications and that are compatible with solar-energy systems being developed.

New Whole-House Solutions Case Study: Evaluating Through-Wall Air Transfer Fans, Pittsburgh, Pennsylvania

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2014-10-01

In this project, Building America team IBACOS performed field testing in a new construction unoccupied test house in Pittsburgh, Pennsylvania, to evaluate heating, ventilating, and air conditioning (HVAC) distribution systems during heating, cooling, and midseason conditions. The team evaluated a market-available through-wall air transfer fan system that provides air to the bedrooms.The relative ability of this system was considered with respect to relevant Air Conditioning Contractors of America and ASHRAE standards for house temperature uniformity and stability.

Physiological and subjective responses in the elderly when using floor heating and air conditioning systems.

PubMed

Hashiguchi, Nobuko; Tochihara, Yutaka; Ohnaka, Tadakatsu; Tsuchida, Chiaki; Otsuki, Tamio

2004-11-01

The purpose of this study was to investigate the effects of a floor heating and air conditioning system on thermal responses of the elderly. Eight elderly men and eight university students sat for 90 minutes in a chair under the following 3 conditions: air conditioning system (A), floor heating system (F) and no heating system (C). The air temperature of sitting head height for condition A was 25 degrees C, and the maximum difference in vertical air temperature was 4 degrees C. The air and floor temperature for condition F were 21 and 29 degrees C, respectively. The air temperature for condition C was 15 degrees C. There were no significant differences in rectal temperature and mean skin temperature between condition A and F. Systolic blood pressure of the elderly men in condition C significantly increased compared to those in condition A and F. No significant differences in systolic blood pressure between condition A and F were found. The percentage of subjects who felt comfortable under condition F was higher than that of those under condition A in both age groups, though the differences between condition F and A was not significant. Relationships between thermal comfort and peripheral (e.g., instep, calf, hand) skin temperature, and the relationship between thermal comfort and leg thermal sensation were significant for both age groups. However, the back and chest skin temperature and back thermal sensation for the elderly, in contrast to that for the young, was not significantly related to thermal comfort. These findings suggested that thermal responses and physiological strain using the floor heating system did not significantly differ from that using the air conditioning system, regardless of the subject age and despite the fact that the air temperature with the floor heating system was lower. An increase in BP for elderly was observed under the condition in which the air temperature was 15 degrees C, and it was suggested that it was necessary for the elderly people to heat the room somehow in winter. Moreover, it is particularly important for elderly people to avoid a decrease in peripheral skin temperature, and maintain awareness of the warmth of peripheral areas, such as the leg, in order to ensure thermal comfort.

78 FR 32617 - Proposed Modification of Significant New Uses of 1-Propene, 2,3,3,3-tetrafluoro-

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-31

... vehicle air conditioning systems in new passenger cars and vehicles as reported in the original PMN is not... attempting to recharge air conditioning systems in vehicles originally charged with the refrigerant... substance by consumers to recharge air conditioning systems in vehicles originally charged with the...

No-reheat air-conditioning

NASA Technical Reports Server (NTRS)

Obler, H. D.

1980-01-01

Air conditioning system, for environmentally controlled areas containing sensitive equipment, regulates temperature and humidity without wasteful and costly reheating. System blends outside air with return air as dictated by various sensors to ensure required humidity in cooled spaces (such as computer room).

The Effect of Computers on School Air-Conditioning.

ERIC Educational Resources Information Center

Fickes, Michael

2000-01-01

Discusses the issue of increased air-conditioning demand when schools equip their classrooms with computers that require enhanced and costlier air-conditioning systems. Air-conditioning costs are analyzed in two elementary schools and a middle school. (GR)

Heat pipes for terrestrial applications in dehumidification systems

NASA Technical Reports Server (NTRS)

Khattar, Mukesh K.

1988-01-01

A novel application of heat pipes which greatly enhances dehumidification performance of air-conditioning systems is presented. When an air-to-air heat pipe heat exchanger is placed between the warm return air and cold supply air streams of an air conditioner, heat is efficiently transferred from the return air to the supply air. As the warm return air precools during this process, it moves closer to its dew-point temperature. Therefore, the cooling system works less to remove moisture. This paper discusses the concept, its benefits, the challenges of incorporating heat pipes in an air-conditioning system, and the preliminary results from a field demonstration of an industrial application.

Design and demonstration of a storage-assisted air conditioning system

NASA Astrophysics Data System (ADS)

Rizzuto, J. E.

1981-03-01

The system is a peak-shaving system designed to provide a levelized air conditioning load. The system also requires minimum air conditioner and thermal storage capacity. The storage-assisted air conditioning system uses a Glauber's salt-based phase change material in sausage like containers called CHUBS. The CHUBS are two (2) inches in diameter and 20 inches long. They are stacked in modules of 64 CHUBS which are appropriately spaced and oriented in the storage system so that air may pass perpendicular to the long axis of the CHUBS. The phase change material, has a thermal storage capacity in the range of 45 to 50 Btu/lb and a transition temperature of approximately 55 F.

76 FR 59665 - Notice of Intent To Grant Exclusive Patent License; OxiCool, Inc.

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-27

... fields of use on commercial and residential air conditioning systems, to practice in the United States (U... Air-Conditioning System, issued June 05, 2001//U.S. Patent Application No. 12/537,852: Air Conditioning System//Navy Case No. PAX83, filed August 07, 2009; and all U.S. and International applications...

Hygiene guideline for the planning, installation, and operation of ventilation and air-conditioning systems in health-care settings - Guideline of the German Society for Hospital Hygiene (DGKH).

PubMed

Külpmann, Rüdiger; Christiansen, Bärbel; Kramer, Axel; Lüderitz, Peter; Pitten, Frank-Albert; Wille, Frank; Zastrow, Klaus-Dieter; Lemm, Friederike; Sommer, Regina; Halabi, Milo

2016-01-01

Since the publication of the first "Hospital Hygiene Guideline for the implementation and operation of air conditioning systems (HVAC systems) in hospitals" (http://www.krankenhaushygiene.de/informationen/fachinformationen/leitlinien/12) in 2002, it was necessary due to the increase in knowledge, new regulations, improved air-conditioning systems and advanced test methods to revise the guideline. Based on the description of the basic features of ventilation concepts, its hygienic test and the usage-based requirements for ventilation, the DGKH section "Ventilation and air conditioning technology" attempts to provide answers for the major air quality issues in the planning, design and the hygienically safe operation of HVAC systems in rooms of health care.

The necessity of HVAC system for the registered architectural cultural heritage building

NASA Astrophysics Data System (ADS)

Popovici, Cătălin George; Hudişteanu, Sebastian Valeriu; Cherecheş, Nelu-Cristian

2018-02-01

This study is intended to highlight the role of the ventilation and air conditioning system for a theatre. It was chosen as a case study the "Vasile Alecsandri" National Theatre of Jassy. The paper also sought to make a comparison in three distinct scenarios for HVAC Main Hall system - ventilation and air conditioning system of the Main Hall doesn't work; only the ventilation system of the Main Hall works and ventilation and air conditioning system of the Main Hall works. For analysing the comfort parameters, the ANSYS-Fluent software was used to build a 2D model of the building and simulation of HVAC system functionality during winter season, in all three scenarios. For the studied scenarios, the external conditions of Jassy and the indoor conditions of the theatre, when the entire spectacle hall is occupied were considered. The main aspects evaluated for each case were the air temperature, air velocity and relative humidity. The results are presented comparatively as plots and spectra of the interest parameters.

Low-Flow Liquid Desiccant Air Conditioning: General Guidance and Site Considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozubal, E.; Herrmann, L.; Deru, M.

2014-09-01

Dehumidification or latent cooling in buildings is an area of growing interest that has been identified as needing more research and improved technologies for higher performance. Heating, ventilating, and air-conditioning (HVAC) systems typically expend excessive energy by using overcool-and-reheat strategies to dehumidify buildings. These systems first overcool ventilation air to remove moisture and then reheat the air to meet comfort requirements. Another common strategy incorporates solid desiccant rotors that remove moisture from the air more efficiently; however, these systems increase fan energy consumption because of the high airside pressure drop of solid desiccant rotors and can add heat of absorptionmore » to the ventilation air. Alternatively, liquid desiccant air-conditioning (LDAC) technology provides an innovative dehumidification solution that: (1) eliminates the need for overcooling and reheating from traditional cooling systems; and (2) avoids the increased fan energy and air heating from solid desiccant rotor systems.« less

Modeling validation and control analysis for controlled temperature and humidity of air conditioning system.

PubMed

Lee, Jing-Nang; Lin, Tsung-Min; Chen, Chien-Chih

2014-01-01

This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14 °C, 0006 kg(w)/kg(da) in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system.

Modeling Validation and Control Analysis for Controlled Temperature and Humidity of Air Conditioning System

PubMed Central

Lee, Jing-Nang; Lin, Tsung-Min

2014-01-01

This study constructs an energy based model of thermal system for controlled temperature and humidity air conditioning system, and introduces the influence of the mass flow rate, heater and humidifier for proposed control criteria to achieve the controlled temperature and humidity of air conditioning system. Then, the reliability of proposed thermal system model is established by both MATLAB dynamic simulation and the literature validation. Finally, the PID control strategy is applied for controlling the air mass flow rate, humidifying capacity, and heating, capacity. The simulation results show that the temperature and humidity are stable at 541 sec, the disturbance of temperature is only 0.14°C, 0006 kgw/kgda in steady-state error of humidity ratio, and the error rate is only 7.5%. The results prove that the proposed system is an effective controlled temperature and humidity of an air conditioning system. PMID:25250390

Criterion-Referenced Test (CRT) Items for Air Conditioning, Heating and Refrigeration.

ERIC Educational Resources Information Center

Davis, Diane, Ed.

These criterion-referenced test (CRT) items for air conditioning, heating, and refrigeration are keyed to the Missouri Air Conditioning, Heating, and Refrigeration Competency Profile. The items are designed to work with both the Vocational Instructional Management System and Vocational Administrative Management System. For word processing and…

Simplified Space Conditioning in Low-Load Homes: Results from Pittsburgh, Pennsylvania, New Construction Unoccupied Test House

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poerschke, A.; Stecher, D.

2014-06-01

Field testing was performed in a new construction unoccupied test house in Pittsburgh, Pennsylvania. Four air-based heating, ventilation, and air conditioning distribution systems--a typical airflow ducted system to the bedrooms, a low airflow ducted system to the bedrooms, a system with transfer fans to the bedrooms, and a system with no ductwork to the bedrooms--were evaluated during heating, cooling, and midseason conditions. The relative ability of each system was assessed with respect to relevant Air Conditioning Contractors of America and ASHRAE standards for house temperature uniformity and stability, respectively.

Seminar 14 - Desiccant Enhanced Air Conditioning: Desiccant Enhanced Evaporative Air Conditioning (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozubal, E.

2013-02-01

This presentation explains how liquid desiccant based coupled with an indirect evaporative cooler can efficiently produce cool, dry air, and how a liquid desiccant membrane air conditioner can efficiently provide cooling and dehumidification without the carryover problems of previous generations of liquid desiccant systems. It provides an overview to a liquid desiccant DX air conditioner that can efficiently provide cooling and dehumidification to high latent loads without the need for reheat, explains how liquid desiccant cooling and dehumidification systems can outperform vapor compression based air conditioning systems in hot and humid climates, explains how liquid desiccant cooling and dehumidification systemsmore » work, and describes a refrigerant free liquid desiccant based cooling system.« less

RESULTS OF A PILOT FIELD STUDY TO EVALUATE THE EFFECTIVENESS OF CLEANING RESIDENTIAL HEATING AND AIR-CONDITIONING SYSTEMS AND THE IMPACT ON INDOOR AIR QUALITY AND SYSTEM PERFORMANCE

EPA Science Inventory

The report discusses and gives results of a pilot field study to evaluate the effectiveness of air duct cleaning (ADC) as a source removal technique in residential heating and air-conditioning (HAC) systems and its impact on airborne particle, fiber, and bioaerosol concentrations...

[Effectiveness of the maintenance operations on the air conditioning systems of a university building in relation to the microbiological quality of the air indoor].

PubMed

De Filippis, Patrizia; Spinaci, Anna; Coia, Maura; Maggi, Oriana; Panà, Augusto

2003-01-01

The microbiological quality of the air indoor is influenced from various factors and one of the most important is represented from the maintenance of the conditioning systems. In this study it has been estimated the effectiveness of an intervention of cleaning and maintenance on the systems of conditioning of an university building executing sampling before and after such intervention. The two results were confronted and it is observed as the maintenance of the air conditioners has influenced on the quality of the air indoor.

24 CFR 3280.714 - Appliances, cooling.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Systems § 3280.714 Appliances, cooling. (a) Every air conditioning unit or a combination air conditioning...) Mechanical air conditioners shall be rated in accordance with the ARI Standard 210/240-89 Unitary Air Conditioning and Air Source Unitary Heat Pump Equipment and certified by ARI or other nationally recognized...

24 CFR 3280.714 - Appliances, cooling.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Systems § 3280.714 Appliances, cooling. (a) Every air conditioning unit or a combination air conditioning...) Mechanical air conditioners shall be rated in accordance with the ARI Standard 210/240-89 Unitary Air Conditioning and Air Source Unitary Heat Pump Equipment and certified by ARI or other nationally recognized...

Building America Case Study: Evaluating Through-Wall Air Transfer Fans, Pittsburgh, Pennsylvania (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2014-10-01

In this project, Building America team IBACOS performed field testing in a new construction unoccupied test house in Pittsburgh, Pennsylvania to evaluate heating, ventilating, and air conditioning (HVAC) distribution systems during heating, cooling, and midseason conditions. Four air-based HVAC distribution systems were assessed:-a typical airflow ducted system to the bedrooms, a low airflow ducted system to the bedrooms, a system with transfer fans to the bedrooms, and a system with no ductwork to the bedrooms. The relative ability of each system was considered with respect to relevant Air Conditioning Contractors of America and ASHRAE standards for house temperature uniformity andmore » stability, respectively.« less

Bi-level Optimization Method of Air-conditioning System Based on Office Building Energy Storage Characteristics

NASA Astrophysics Data System (ADS)

Wang, Qingze; Chen, Xingying; Ji, Li; Liao, Yingchen; Yu, Kun

2017-05-01

The air-conditioning system of office building is a large power consumption terminal equipment, whose unreasonable operation mode leads to low energy efficiency. Realizing the optimization of the air-conditioning system has become one of the important research contents of the electric power demand response. In this paper, in order to save electricity cost and improve energy efficiency, bi-level optimization method of air-conditioning system based on TOU price is put forward by using the energy storage characteristics of the office building itself. In the upper level, the operation mode of the air-conditioning system is optimized in order to minimize the uses’ electricity cost in the premise of ensuring user’ comfort according to the information of outdoor temperature and TOU price, and the cooling load of the air-conditioning is output to the lower level; In the lower level, the distribution mode of cooling load among the multi chillers is optimized in order to maximize the energy efficiency according to the characteristics of each chiller. Finally, the experimental results under different modes demonstrate that the strategy can improve the energy efficiency of chillers and save the electricity cost for users.

IMPACT OF HEATING AND AIR CONDITIONING SYSTEM OPERATION AND LEAKAGE ON VENTILATION AND INTERCOMPARTMENT TRANSPORT: STUDIES IN UNOCCUPIED AND OCCUPIED TENNESSEE VALLEY HOMES

EPA Science Inventory

Forced-air heating and air conditioning (HAC) systems caused an average and maximum increase in air infiltration rates of 1.8- and 4.3-fold, respectively, during brief whole-house studies of tracer gas decay In 39 occupied houses. An average Increase in air infiltration rate of 0...

76. DETAIL OF AIRCONDITIONING DUCT BETWEEN PORTABLE PAYLOAD AIRCONDITIONING SYSTEM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

76. DETAIL OF AIR-CONDITIONING DUCT BETWEEN PORTABLE PAYLOAD AIR-CONDITIONING SYSTEM AND LSB (BLDG. 770) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Simplified Space Conditioning in Low-Load Homes: Results from Pittsburgh, Pennsylvania, New Construction Unoccupied Test House

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poerschke, Andrew; Stecher, Dave

2014-06-01

Field testing was performed in a new construction unoccupied test house in Pittsburgh, PA. Four air-based heating, ventilation, and air conditioning distribution systems—a typical airflow ducted system to the bedrooms, a low airflow ducted system to the bedrooms, a system with transfer fans to the bedrooms, and a system with no ductwork to the bedrooms—were evaluated during heating, cooling, and midseason conditions. The relative ability of each system was assessed with respect to relevant Air Conditioning Contractors of America and ASHRAE standards for house temperature uniformity and stability, respectively.

Occupational exposure to nitrous oxide - the role of scavenging and ventilation systems in reducing the exposure level in operating rooms.

PubMed

Krajewski, Wojciech; Kucharska, Malgorzata; Wesolowski, Wiktor; Stetkiewicz, Jan; Wronska-Nofer, Teresa

2007-03-01

The aim of this study was to assess the level of occupational exposure to nitrous oxide (N(2)O) in operating rooms (ORs), as related to different ventilation and scavenging systems used to remove waste anaesthetic gases from the work environment. The monitoring of N(2)O in the air covered 35 ORs in 10 hospitals equipped with different systems for ventilation and anaesthetic scavenging. The examined systems included: natural ventilation with supplementary fresh air provided by a pressure ventilation system (up to 6 air changes/h); pressure and exhaust ventilation systems equipped with ventilation units supplying fresh air to and discharging contaminated air outside the working area (more than 10 air changes/h); complete air-conditioning system with laminar air flow (more than 15 air changes/h). The measurements were carried out during surgical procedures (general anaesthesia induced intravenously and maintained with inhaled N(2)O and sevofluran delivered through cuffed endotracheal tubes) with connected or disconnected air scavenging. Air was collected from the breathing zone of operating personnel continuously through the whole time of anaesthesia to Tedlar((R)) bags, and N(2)O concentrations in air samples were analyzed by adsorption gas chromatography/mass spectrometry. N(2)O levels in excess of the occupational exposure limit (OEL) value of 180mg/m(3) were registered in all ORs equipped with ventilation systems alone. The OEL value was exceeded several times in rooms with natural ventilation plus supplementary pressure ventilations and twice or less in those with pressure/exhaust ventilation systems or air conditioning. N(2)O levels below or within the OEL value were observed in rooms where the system of air conditioning or pressure/exhaust ventilation was combined with scavenging systems. Systems combining natural/pressure ventilation with scavenging were inadequate to maintain N(2)O concentration below the OEL value. Air conditioning and an efficient pressure/exhaust ventilation (above 12 air exchanges/h) together with efficient active scavenging systems are sufficient to sustain N(2)O exposure in ORs at levels below or within the OEL value of 180mg/m(3).

Strategy Guideline. Compact Air Distribution Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burdick, Arlan

2013-06-01

This guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balancedmore » HVAC system, and overall improved energy efficiency of the home.« less

Strategy Guideline: Compact Air Distribution Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burdick, A.

2013-06-01

This Strategy Guideline discusses the benefits and challenges of using a compact air distribution system to handle the reduced loads and reduced air volume needed to condition the space within an energy efficient home. Traditional systems sized by 'rule of thumb' (i.e., 1 ton of cooling per 400 ft2 of floor space) that 'wash' the exterior walls with conditioned air from floor registers cannot provide appropriate air mixing and moisture removal in low-load homes. A compact air distribution system locates the HVAC equipment centrally with shorter ducts run to interior walls, and ceiling supply outlets throw the air toward themore » exterior walls along the ceiling plane; alternatively, high sidewall supply outlets throw the air toward the exterior walls. Potential drawbacks include resistance from installing contractors or code officials who are unfamiliar with compact air distribution systems, as well as a lack of availability of low-cost high sidewall or ceiling supply outlets to meet the low air volumes with good throw characteristics. The decision criteria for a compact air distribution system must be determined early in the whole-house design process, considering both supply and return air design. However, careful installation of a compact air distribution system can result in lower material costs from smaller equipment, shorter duct runs, and fewer outlets; increased installation efficiencies, including ease of fitting the system into conditioned space; lower loads on a better balanced HVAC system, and overall improved energy efficiency of the home.« less

Silver zeolite antimicrobial activity in aluminium heating, ventilation and air conditioning system ducts.

PubMed

Rizzetto, R; Mansi, A; Panatto, D; Rizzitelli, E; Tinteri, C; Sasso, T; Gasparini, R; Crovari, P

2008-03-01

Air pollution in confined environments is a serious health problem, in that most people spend long periods indoors (in homes, offices, classrooms etc.). Some people (children, the elderly, heart disease patients, asthmatic or allergic subjects) are at greater risk because of their conditions of frailty. The growing use of air-conditioning systems in many public and private buildings aggravates this health risk, especially when these systems are not correctly installed or regularly serviced. The aim of our study was to verify the capacity of Ag+ ions to stop the growth of bacteria and moulds inside the ducts of Heating, Ventilation and Air Conditioning system ducts (HVAC) systems when these ducts were lined with active Ag+ ions zeolite-coated panels. A Y-shaped HVAC model with two branches was used; one branch was made of traditional galvanized iron, as was the whole system, while the other was lined with active Ag+ zeolite-coated polyurethane panels. During the test, samples of dust present inside both ducts were collected and seeded in liquid and solid media to detect bacteria and moulds. The presence of bacteria was also sought in the air emerging from the outlets of both ducts. Tests made on samples of particulate collected from the two different ducts revealed a lower total bacterial load in the samples collected from the Ag+ zeolite-coated duct than in the samples from the traditional Zn galvanized duct. In addition, the values of bacterial load found in the air emerging from the Ag+ ions zeolite-lined duct were 5 times lower than those found in the air from the traditional galvanized iron duct. The utilization of Ag+ zeolite-coated panels in air-conditioning systems could improve the quality of the emerging air in comparison with traditional installations in galvanized iron. This innovation could prove particularly advantageous in the event of accidents during the installation of air-conditioning systems or of contaminated aerosols coming from outside.

40 CFR 86.165-12 - Air conditioning idle test procedure.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Applicability. This section describes procedures for determining air conditioning-related CO2 emissions from... used to qualify for air conditioning efficiency CO2 credits according to § 86.1866-12(c). (b) Overview... at idle when CO2 emissions are measured without any air conditioning systems operating, followed by a...

40 CFR 86.165-12 - Air conditioning idle test procedure.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Applicability. This section describes procedures for determining air conditioning-related CO2 emissions from... used to qualify for air conditioning efficiency CO2 credits according to § 86.1866-12(c). (b) Overview... at idle when CO2 emissions are measured without any air conditioning systems operating, followed by a...

40 CFR 86.165-12 - Air conditioning idle test procedure.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Applicability. This section describes procedures for determining air conditioning-related CO2 emissions from... used to qualify for air conditioning efficiency CO2 credits according to § 86.1866-12(c). (b) Overview... at idle when CO2 emissions are measured without any air conditioning systems operating, followed by a...

40 CFR 86.165-12 - Air conditioning idle test procedure.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Applicability. This section describes procedures for determining air conditioning-related CO2 emissions from... used to qualify for air conditioning efficiency CO2 credits according to § 86.1866-12(c). (b) Overview... at idle when CO2 emissions are measured without any air conditioning systems operating, followed by a...

Performance analysis of an air drier for a liquid dehumidifier solar air conditioning system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Queiroz, A.G.; Orlando, A.F.; Saboya, F.E.M.

1988-05-01

A model was developed for calculating the operating conditions of a non-adiabatic liquid dehumidifier used in solar air conditioning systems. In the experimental facility used for obtaining the data, air and triethylene glycol circulate countercurrently outside staggered copper tubes which are the filling of an absorption tower. Water flows inside the copper tubes, thus cooling the whole system and increasing the mass transfer potential for drying air. The methodology for calculating the mass transfer coefficient is based on the Merkel integral approach, taking into account the lowering of the water vapor pressure in equilibrium with the water glycol solution.

Managing Refrigerant Emissions

EPA Pesticide Factsheets

Access information on EPA's efforts to address ozone layer depletion by reducing emissions of refrigerants from stationary refrigeration and air conditioning systems and motor vehicle air conditioning systems.

The application of condensate water as an additional cooling media intermittently in condenser of a split air conditioning

NASA Astrophysics Data System (ADS)

Ardita, I. N.; Subagia, I. W. A.

2018-01-01

The condensate water produced by indoor a split air conditioning is usually not utilized and thrown away into the environment. The result of measurement shows that the temperature of condensate water produced by split air conditioning is quite low, that is 19-22 °C at the rate of 16-20 mL / min and it has PH balance. Under such conditions, Air Condensate produced by split air conditioning should still be recovered as an additional cooling medium on the condenser. This research will re-investigate the use of condensate water as an intermittent additional cooling of the condenser to increase the cooling capacity and performance of the air conditioning system. This research is done by experimental method whose implementation includes; designing and manufacturing of experimental equipment, mounting measuring tools, experimental data retrieval, data processing and yield analysis. The experimental results show that the use of condensate water as an intermittent additional cooling medium on split air conditioning condenser can increase the refrigeration effect about 2%, cooling capacity about 4% and 7% of COP system. Experimental results also show a decrease in power consumption in the system compressor about 3%

Multisensor System for Isotemporal Measurements to Assess Indoor Climatic Conditions in Poultry Farms

PubMed Central

Bustamante, Eliseo; Guijarro, Enrique; García-Diego, Fernando-Juan; Balasch, Sebastián; Hospitaler, Antonio; Torres, Antonio G.

2012-01-01

The rearing of poultry for meat production (broilers) is an agricultural food industry with high relevance to the economy and development of some countries. Periodic episodes of extreme climatic conditions during the summer season can cause high mortality among birds, resulting in economic losses. In this context, ventilation systems within poultry houses play a critical role to ensure appropriate indoor climatic conditions. The objective of this study was to develop a multisensor system to evaluate the design of the ventilation system in broiler houses. A measurement system equipped with three types of sensors: air velocity, temperature and differential pressure was designed and built. The system consisted in a laptop, a data acquisition card, a multiplexor module and a set of 24 air temperature, 24 air velocity and two differential pressure sensors. The system was able to acquire up to a maximum of 128 signals simultaneously at 5 second intervals. The multisensor system was calibrated under laboratory conditions and it was then tested in field tests. Field tests were conducted in a commercial broiler farm under four different pressure and ventilation scenarios in two sections within the building. The calibration curves obtained under laboratory conditions showed similar regression coefficients among temperature, air velocity and pressure sensors and a high goodness fit (R2 = 0.99) with the reference. Under field test conditions, the multisensor system showed a high number of input signals from different locations with minimum internal delay in acquiring signals. The variation among air velocity sensors was not significant. The developed multisensor system was able to integrate calibrated sensors of temperature, air velocity and differential pressure and operated succesfully under different conditions in a mechanically-ventilated broiler farm. This system can be used to obtain quasi-instantaneous fields of the air velocity and temperature, as well as differential pressure maps to assess the design and functioning of ventilation system and as a verification and validation (V&V) system of Computational Fluid Dynamics (CFD) simulations in poultry farms. PMID:22778611

Building Component Maintenance and Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems

DTIC Science & Technology

1991-05-01

Building Component Maintenance and Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems by Edgar S. Neely Robert D. Neathammer...Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems RDTE dated 1980EIMB 1984 - 1989 6. AUTHOR(S) Edgar S. Neely, Robert D...Laboratory (USACERL). The Principal Investigators were Dr. Edgar Neely and Mr. Robert Neathammer (USACERL-FS). The primary contractor for much of the

9 CFR 3.65 - Terminal facilities.

Code of Federal Regulations, 2010 CFR

2010-01-01

..., or air conditioning and may be ventilated or air circulated by means of fans, blowers, or an air conditioning system so as to minimize drafts, odors, and moisture condensation. Auxiliary ventilation, such as exhaust fans and vents or fans or blowers or air conditioning shall be used for any animal holding area...

24 CFR 3280.714 - Appliances, cooling.

Code of Federal Regulations, 2014 CFR

2014-04-01

... any air conditioning or comfort-cooling system installed in a manufactured home shall employ a type of...) Every air conditioning unit or a combination air conditioning and heating unit shall be listed or... installed in accordance with the terms of its listing. (1) Mechanical air conditioners shall be rated in...

Small Business Voucher CRADA Report: Natural Gas Powered HVAC System for Commercial and Residential Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Betts, Daniel; Ally, Moonis Raza; Mudiraj, Shyam

Be Power Tech is commercializing BeCool, the first integrated electricity-producing heating, ventilation, and air conditioning (HVAC) system using a non-vapor compression cycle (VCC), packaged rooftop HVAC unit that also produces base-load electricity, heating, ventilation, and air conditioning. BeCool is a distributed energy resource with energy storage that eliminates the tremendous peak electricity demand associated with commonly used electricity-powered vapor compression air conditioning systems.

Floating loop method for cooling integrated motors and inverters using hot liquid refrigerant

DOEpatents

Hsu, John S.; Ayers, Curtis W.; Coomer, Chester; Marlino, Laura D.

2007-03-20

A method for cooling vehicle components using the vehicle air conditioning system comprising the steps of: tapping the hot liquid refrigerant of said air conditioning system, flooding a heat exchanger in the vehicle component with said hot liquid refrigerant, evaporating said hot liquid refrigerant into hot vapor refrigerant using the heat from said vehicle component, and returning said hot vapor refrigerant to the hot vapor refrigerant line in said vehicle air conditioning system.

Floating Loop System For Cooling Integrated Motors And Inverters Using Hot Liquid Refrigerant

DOEpatents

Hsu, John S [Oak Ridge, TN; Ayers, Curtis W [Kingston, TN; Coomer, Chester [Knoxville, TN; Marlino, Laura D [Oak Ridge, TN

2006-02-07

A floating loop vehicle component cooling and air-conditioning system having at least one compressor for compressing cool vapor refrigerant into hot vapor refrigerant; at least one condenser for condensing the hot vapor refrigerant into hot liquid refrigerant by exchanging heat with outdoor air; at least one floating loop component cooling device for evaporating the hot liquid refrigerant into hot vapor refrigerant; at least one expansion device for expanding the hot liquid refrigerant into cool liquid refrigerant; at least one air conditioning evaporator for evaporating the cool liquid refrigerant into cool vapor refrigerant by exchanging heat with indoor air; and piping for interconnecting components of the cooling and air conditioning system.

40 CFR 86.1866-12 - CO2 fleet average credit programs.

Code of Federal Regulations, 2012 CFR

2012-07-01

... technologies designed to reduce air conditioning refrigerant leakage over the useful life of their passenger....1865-12 by implementing specific air conditioning system technologies designed to reduce air... performance improvement for the system of greater than 10% when compared to previous industry standard designs...

Mechanical model for simulating the conditioning of air in the respiratory tract.

PubMed

Bergonse Neto, Nelson; Von Bahten, Luiz Carlos; Moura, Luís Mauro; Coelho, Marlos de Souza; Stori Junior, Wilson de Souza; Bergonse, Gilberto da Fontoura Rey

2007-01-01

To create a mechanical model that could be regulated to simulate the conditioning of inspired and expired air with the same normal values of temperature, pressure, and relative humidity as those of the respiratory system of a healthy young man on mechanical ventilation. Using several types of materials, a mechanical device was built and regulated using normal values of vital capacity, tidal volume, maximal inspiratory pressure, positive end-expiratory pressure, and gas temperature in the system. The device was submitted to mechanical ventilation for a period of 29.8 min. The changes in the temperature of the air circulating in the system were recorded every two seconds. The statistical analysis of the data collected revealed that the device was approximately as efficient in the conditioning of air as is the respiratory system of a human being. By the study endpoint, we had developed a mechanical device capable of simulating the conditioning of air in the respiratory tract. The device mimics the conditions of temperature, pressure, and relative humidity seen in the respiratory system of healthy individuals.

Natural convection liquid desiccant loop as an auxiliary air conditioning system: investigating the operational parameters

NASA Astrophysics Data System (ADS)

Fazilati, Mohammad Ali; Alemrajabi, Ali Akbar; Sedaghat, Ahmad

2018-03-01

Liquid desiccant air conditioning system with natural convection was presented previously as a new generation of AC systems. The system consists of two three-fluid energy exchangers namely absorber and regenerator in which the action of air dehumidifying and desiccant regeneration is done, respectively. The influence of working parameters on system performance including the heat source and heat sink temperature, concentration of desiccant solution fills the system initially and humidity content of inlet air to regenerator is investigated experimentally. The heat source temperatures of 50 °C and 60 °C, heat sink temperatures of 15 °C and 20 °C and desiccant concentrations of 30% and 34%, are examined here. The inlet air to regenerator has temperature of 38.5 °C and three relative humidity of 14%, 38% and 44%. In all experiments, the inlet air to absorber has temperature of 31 °C and relative humidity of 75%. By inspecting evaluation indexes of system, it is revealed that higher startup desiccant concentration solution is more beneficial for all study cases. It is also observed although the highest/lowest temperature heat source/heat sink is most suitable for best system operation, increasing the heat source temperature should be accompanied with decreasing heat sink temperature. Using drier air stream for regenerator inlet does not necessarily improve system performance; and the air stream with proper value of humidity content should be employed. Finally after running the system in its best working condition, the coefficient of performance (COP) reached 4.66 which verified to be higher than when the same air conditioning task done by a conventional vapor compression system, in which case the COP was 3.38.

Environmental Control Systems

NASA Technical Reports Server (NTRS)

Rosenbush, F. M.

1982-01-01

Materials illustrating a presentation on environment control systems for electric flight systems are presented. Schematics and flow diagrams of fresh air source and air conditioning systems, and vapor cycle and air cycle parts lists are presented.

Effects of lighting and air-conditioning systems on growth weight and functional composition of frill-lettuce produced in plant factory

NASA Astrophysics Data System (ADS)

Yoshida, Atsumasa; Okamura, Nobuya; Furukawa, Hajime; Myojin, Chiho; Moriuchi, Koji; Kinoshita, Shinichi

2017-06-01

The aim of the present study was to develop optimal air-conditioning systems for plant factories. To verify the effect of particular air-conditioning and lighting systems, cultivation experiments were performed with frill-lettuce for two weeks. In the present study, the relationship between the cultivation condition, the yield (i.e., increase in edible portion weight), and the functional components were discussed. Based on the measured data, increased photosynthetic photon flux density increased antioxidative activity and edible portion weight, possibly because high light intensities are stressful for frill lettuce. Antioxidative activity also increased under conditions of low CO2 concentration, weak and strong winds, and high air temperature because these conditions became stresses for the plants. However, a decrease in edible portion weight was observed under these conditions, implying there is a negative correlation between antioxidative activity and edible portion weight.

Application of solar energy to air conditioning systems

NASA Technical Reports Server (NTRS)

Nash, J. M.; Harstad, A. J.

1976-01-01

The results of a survey of solar energy system applications of air conditioning are summarized. Techniques discussed are both solar powered (absorption cycle and the heat engine/Rankine cycle) and solar related (heat pump). Brief descriptions of the physical implications of various air conditioning techniques, discussions of status, proposed technological improvements, methods of utilization and simulation models are presented, along with an extensive bibliography of related literature.

40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

Code of Federal Regulations, 2011 CFR

2011-07-01

... conditioning system compressor, converted to an equivalent roadload component, to the normal dynamometer... driving the SC03 cycle with the air conditioning system operating. (1) Engine revolutions/minute (ERPMt...)(i) (A) and (B) are replaced with 76 °F and 50 grains of water/pound of dry air and the solar heat...

Feedback linearization based control of a variable air volume air conditioning system for cooling applications.

PubMed

Thosar, Archana; Patra, Amit; Bhattacharyya, Souvik

2008-07-01

Design of a nonlinear control system for a Variable Air Volume Air Conditioning (VAVAC) plant through feedback linearization is presented in this article. VAVAC systems attempt to reduce building energy consumption while maintaining the primary role of air conditioning. The temperature of the space is maintained at a constant level by establishing a balance between the cooling load generated in the space and the air supply delivered to meet the load. The dynamic model of a VAVAC plant is derived and formulated as a MIMO bilinear system. Feedback linearization is applied for decoupling and linearization of the nonlinear model. Simulation results for a laboratory scale plant are presented to demonstrate the potential of keeping comfort and maintaining energy optimal performance by this methodology. Results obtained with a conventional PI controller and a feedback linearizing controller are compared and the superiority of the proposed approach is clearly established.

Improving the performance of air-conditioning systems in an ASEAN (Association of South East Asian Nations) climate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Busch, J.F.; Warren, M.L.

1988-09-01

This paper describes an analysis of air conditioning performance under hot and humid tropical climate conditions appropriate to the Association of South East Asian Nations (ASEAN) countries. This region, with over 280 million people, has one of the fastest economic and energy consumption growth rates in the world. The work reported here is aimed at estimating the conservation potential derived from good design and control of air conditioning systems in commercial buildings. To test the performance of different air conditioning system types and control options, whole building energy performance was simulated using DOE-2. The 5100 m/sup 2/ (50,000 ft/sup 2/)more » prototype office building module was previously used in earlier commercial building energy standards analysis for Malaysia and Singapore. In general, the weather pattern for ASEAN countries is uniform, with hot and humid air masses known as ''monsoons'' dictating the weather patterns. Since a concentration of cities occurs near the tip of the Malay peninsula, hourly temperature, humidity, and wind speed data for Kuala Lumpur was used for the analysis. Because of the absence of heating loads in ASEAN regions, we have limited air conditioning configurations to two pipe fan coil, constant volume, variable air volume, powered induction, and ceiling bypass configurations. Control strategies were varied to determine the conservation potential in both energy use and peak electric power demands. Sensitivities including fan control, pre-cooling and night ventilation, supply air temperature control, zone temperature set point, ventilation and infiltration, daylighting and internal gains, and system sizing were examined and compared with a base case which was a variable air volume system with no reheat or economizer. Comfort issues, such as over-cooling and space humidity, were also examined.« less

40 CFR 86.311-79 - Miscellaneous equipment; specifications.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Intake air humidity and temperature measurements. (1) Humidity conditioned air supply. Air that has had... supply, the humidity measurements must be made within the intake air supply system, and after the humidity conditioning has taken place. (2) Nonconditioned air supply. Humidity measurements in non...

Small photovoltaic setup for the air conditioning system

NASA Astrophysics Data System (ADS)

Masiukiewicz, Maciej

2017-10-01

The increasing interest in air conditioning systems for residential applications in Poland will certainly increase the demand for electricity during the summer period. Due to this fact a growing interest in solutions that help to lower the electricity consumption in this sector is observed. The problem of increased energy demand for air conditioning purposes can be solved by transfer the consumption of electricity from the grid system to renewable energy sources (RES). The greatest demand for cooling occurs during the biggest sunlight. This is the basis for the analysis of technical power system based on photovoltaic cells (PV) to power the split type air conditioner. The object of the study was the commercial residential airconditioning inverter units with a capacity of 2.5kW. A network electricity production system for their own use with the possibility of buffering energy in batteries (OFF-GRID system). Currently, on the Polish market, there are no developed complete solutions dedicated to air conditioning systems based on PV. In Poland, solar energy is mainly used for heat production in solar collectors. The proposed solution will help to increase the popularity of PV systems in the Polish market as an alternative to other RES. The basic conclusion is that the amount of PV energy generated was sufficient to cover the daily energy requirement of the air conditioner.

Total environmental warming impact (TEWI) calculations for alternative automative air-conditioning systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sand, J.R.; Fischer, S.K.

1997-01-01

The Montreal Protocol phase-out of chlorofluorocarbons (CFCs) has required manufacturers to develop refrigeration and air-conditioning systems that use refrigerants that can not damage stratospheric ozone. Most refrigeration industries have adapted their designs to use hydrochlorofluorocarbon (HCFC) or hydrofluorocarbon (HFC) refrigerants; new automobile air- conditioning systems use HFC-134a. These industries are now being affected by scientific investigations of greenhouse warming and questions about the effects of refrigerants on global warming. Automobile air-conditioning has three separate impacts on global warming; (1) the effects of refrigerant inadvertently released to the atmosphere from accidents, servicing, and leakage; (2) the efficiency of the cooling equipmentmore » (due to the emission of C0{sub 2} from burning fuel to power the system); and (3) the emission of C0{sub 2} from burning fuel to transport the system. The Total Equivalent Warming Impact (TEWI) is an index that should be used to compare the global warming effects of alternative air-conditioning systems because it includes these contributions from the refrigerant, cooling efficiency, and weight. This paper compares the TEWI of current air-conditioning systems using HFC-134a with that of transcritical vapor compression system using carbon dioxide and systems using flammable refrigerants with secondary heat transfer loops. Results are found to depend on both climate and projected efficiency of C0{sub 2}systems. Performance data on manufacturing prototype systems are needed to verify the potential reductions in TEWI. Extensive field testing is also required to determine the performance, reliability, and ``serviceability`` of each alternative to HFC-134a to establish whether the potential reduction of TEWI can be achieved in a viable consumer product.« less

The Maintenance of Heating, Ventilating and Air-Conditioning Systems and Indoor Air Quality in Schools: A Guide for School Facility Managers. Technical Bulletin.

ERIC Educational Resources Information Center

Wheeler, Arthur E.

To help maintain good indoor air quality (IAQ) in schools, guidance for the development and implementation of an effective program for maintenance and operation of heating, ventilating, and air-conditioning (HVAC) systems are discussed. Frequently, a building's occupants will complain about IAQ when the temperature or humidity are at uncomfortable…

Desiccant-based dehumidification system and method

DOEpatents

Fischer, John C.

2004-06-22

The present invention provides an apparatus for dehumidifying air supplied to an enclosed space by an air conditioning unit. The apparatus includes a partition separating the interior of the housing into a supply portion and a regeneration portion. The supply portion has an inlet for receiving supply air from the air conditioning unit and an outlet for supplying air to the enclosed space. A regeneration fan creates the regeneration air stream. The apparatus includes an active desiccant wheel positioned such that a portion of the wheel extends into the supply portion and a portion of the wheel extends into the regeneration portion, so that the wheel can rotate through the supply air stream and the regeneration air stream to dehumidify the supply air stream. A heater warms the regeneration air stream as necessary to regenerate the desiccant wheel. The invention also comprises a hybrid system that combines air conditioning and dehumidifying components into a single integrated unit.

Air conditioning system and component therefore distributing air flow from opposite directions

NASA Technical Reports Server (NTRS)

Obler, H. D.; Bauer, H. B. (Inventor)

1974-01-01

The air conditioning system comprises a plurality of separate air conditioning units coupled to a common supply duct such that air may be introduced into the supply duct in two opposite flow directions. A plurality of outlets such as registers or auxiliary or branch ducts communicate with the supply duct and valve means are disposed in the supply duct at at least some of the outlets for automatically channelling a controllable amount of air from the supply duct to the associated outlet regardless of the direction of air flow within the supply duct. The valve means comprises an automatic air volume control apparatus for distribution within the air supply duct into which air may be introduced from two opposite directions. The apparatus incorporates a freely swinging movable vane in the supply duct to automatically channel into the associated outlet only the deflected air flow which has the higher relative pressure.

24 CFR 201.10 - Loan amounts.

Code of Federal Regulations, 2010 CFR

2010-04-01

... dealer's cost of purchasing and installing a central air conditioning system or heat pump, if not... cost of purchasing and installing a central air conditioning system or heat pump, if not installed by...

[Disinfectants and main sanitary and preventive measures for protection of ventilation and air-conditioning systems from Legionella contamination].

PubMed

Gerasimov, V N; Golov, E A; Khramov, M V; Diatlov, I A

2008-01-01

The study was devoted to selection and assessment of disinfecting preparations for prevention of contamination by Legionella. Using system of criteria for quality assessment of disinfectants, seven newdomestic ones belonging to quaternary ammonium compounds class or to oxygen-containing preparations and designed for disinfecting of air-conditioning and ventilation systems were selected. Antibacterial and disinfecting activities of working solutions of disinfectants were tested in laboratory on the test-surfaces and test-objects of premises' air-conditioning and ventilation systems contaminated with Legionella. High antimicrobial and disinfecting activity of new preparations "Dezactiv-M", "ExtraDez", "Emital-Garant", "Aquasept Plus", "Samarovka", "Freesept", and "Ecobreeze Oxy" during their exposure on objects and materials contaminated with Legionella was shown. Main sanitary and preventive measures for defending of air-conditioning and ventilation systems from contamination by Legionella species were presented.

38 CFR 59.50 - Priority list.

Code of Federal Regulations, 2010 CFR

2010-07-01

... utility systems, such as heating and air conditioning systems or building features, such as roof... Americans with Disabilities Act; building systems and utilities (e.g., electrical; heating, ventilation, and air conditioning (HVAC); boiler; medical gasses; roof; elevators); clinical-support facilities (e.g...

38 CFR 59.50 - Priority list.

Code of Federal Regulations, 2011 CFR

2011-07-01

... utility systems, such as heating and air conditioning systems or building features, such as roof... Americans with Disabilities Act; building systems and utilities (e.g., electrical; heating, ventilation, and air conditioning (HVAC); boiler; medical gasses; roof; elevators); clinical-support facilities (e.g...

Heat tube device

NASA Technical Reports Server (NTRS)

Khattar, Mukesh K. (Inventor)

1990-01-01

The present invention discloses a heat tube device through which a working fluid can be circulated to transfer heat to air in a conventional air conditioning system. The heat tube device is disposable about a conventional cooling coil of the air conditioning system and includes a plurality of substantially U-shaped tubes connected to a support structure. The support structure includes members for allowing the heat tube device to be readily positioned about the cooling coil. An actuatable adjustment device is connected to the U-shaped tubes for allowing, upon actuation thereof, for the heat tubes to be simultaneously rotated relative to the cooling coil for allowing the heat transfer from the heat tube device to air in the air conditioning system to be selectively varied.

[Assessment of the air quality improment of cleaning and disinfection on central air-conditioning ventilation system].

PubMed

Liu, Hongliang; Zhang, Lei; Feng, Lihong; Wang, Fei; Xue, Zhiming

2009-09-01

To assess the effect of air quality of cleaning and disinfection on central air-conditioning ventilation systems. 102 air-conditioning ventilation systems in 46 public facilities were sampled and investigated based on Hygienic assessment criterion of cleaning and disinfection of public central air-conditioning systems. Median dust volume decreased from 41.8 g/m2 to 0.4 g/m2, and the percentage of pipes meeting the national standard for dust decreased from 17.3% (13/60) to 100% (62/62). In the dust, median aerobic bacterial count decreased from 14 cfu/cm2 to 1 cfu/cm2. Median aerobic fungus count decreased from 10 cfu/cm2 to 0 cfu/cm2. The percentage of pipes with bacterial and fungus counts meeting the national standard increased from 92.4% (171/185) and 82.2% (152/185) to 99.4% (165/166) and 100% (166/166), respectively. In the ventilation air, median aerobic bacterial count decreased from 756 cfu/m3 to 229 cfu/m3. Median aerobic fungus count decreased from 382 cfu/m3 to 120 cfu/m3. The percentage of pipes meeting the national standard for ventilation air increased from 33.3% (81/243) and 62.1% (151/243) to 79.8% (292/366) and 87.7% (242/276), respectively. But PM10 rose from 0.060 mg/m3 to 0.068 mg/m3, and the percentage of pipes meeting the national standard for PM10 increased from 74.2% (13/60) to 90.2% (46/51). The cleaning and disinfection of central air-conditioning ventilation systems could have a beneficial effect of air quality.

Investigation of the effect of ambient conditions on the performance of solid desiccant cooling cycles

NASA Astrophysics Data System (ADS)

Panaras, G.; Mathioulakis, E.; Belessiotis, V.

2018-01-01

The operation of desiccant air-conditioning systems is characterised by processes implemented to the moist air of the environment; it is, thus, expected to be affected by ambient conditions. The present work aims at quantifying this influence on the basis of an easy-to-implement, steady-state model of the system, presenting an efficiency factors approach, which has been experimentally validated. The analysis examines the behaviour of the ventilation and the recirculation cycles, which constitute the marginal cases regarding the achieved values of the outside air fraction, given the ambient conditions, the desired regeneration temperature and the efficiency of the involved components. The fact of a desiccant cycle undergoing a set of changing ambient conditions by its actual operation is also considered in the analysis. The results provide useful information for the selection of the optimum configuration to the designer of a desiccant air-conditioning system.

Performance and economics of the ACES and alternative residential heating and air conditioning systems in 115 US cities

NASA Astrophysics Data System (ADS)

Abbatiello, L. A.; Nephew, E. A.; Ballou, M. L.

1981-03-01

The efficiency and life cycle costs of the brine chiller minimal annual cycle energy system (ACES) for residential space heating, air conditioning, and water heating requirements are compared with three conventional systems. The conventional systems evaluated are a high performance air-to-air heat pump with an electric resistance water heater, an electric furnace with a central air conditioner and an electric resistance water heater, and a high performance air-to-air heat pump with a superheater unit for hot water production. Monthly energy requirements for a reference single family house are calculated, and the initial cost and annual energy consumption of the systems, providing identical energy services, are computed and compared. The ACES consumes one third to one half ot the electrical energy required by the conventional systems and delivers the same annual loads at comparable costs.

Evaluation of the response of tritium-in-air instrumentation to HT in dry and humid conditions and to HTO vapor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, H.; Dean, J.; Privas, E.

2015-03-15

Nuclear plant operators (power generation, decommissioning and reprocessing operations) are required to monitor releases of tritium species for regulatory compliance and radiation protection purposes. Tritium monitoring is performed using tritium-in-air gas monitoring instrumentation based either on flow-through ion chambers or proportional counting systems. Tritium-in-air monitors are typically calibrated in dry conditions but in service may operate at elevated levels of relative humidity. The NPL (National Physical Laboratory) radioactive gas-in-air calibration system has been used to study the effect of humidity on the response to tritium of two tritium-in-air ion chamber based monitors and one proportional counting system which uses amore » P10/air gas mixture. The response of these instruments to HTO vapour has also been evaluated. In each case, instrument responses were obtained for HT in dry conditions (relative humidity (RH) about 2%), HT in 45% RH, and finally HTO at 45% RH. Instrumentation response to HT in humid conditions has been found to slightly exceed that in dry conditions. (authors)« less

Ecological succession of the microbial communities of an air-conditioning cooling coil in the tropics.

PubMed

Acerbi, E; Chénard, C; Miller, D; Gaultier, N E; Heinle, C E; Chang, V W-C; Uchida, A; Drautz-Moses, D I; Schuster, S C; Lauro, F M

2017-03-01

Air-conditioning systems harbor microorganisms, potentially spreading them to indoor environments. While air and surfaces in air-conditioning systems are periodically sampled as potential sources of indoor microbes, little is known about the dynamics of cooling coil-associated communities and their effect on the downstream airflow. Here, we conducted a 4-week time series sampling to characterize the succession of an air-conditioning duct and cooling coil after cleaning. Using an universal primer pair targeting hypervariable regions of the 16S/18S ribosomal RNA, we observed a community succession for the condensed water, with the most abundant airborne taxon Agaricomycetes fungi dominating the initial phase and Sphingomonas bacteria becoming the most prevalent taxa toward the end of the experiment. Duplicate air samples collected upstream and downstream of the coil suggest that the system does not act as ecological filter or source/sink for specific microbial taxa during the duration of the experiment. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Heat pipes for low-humidity applications

NASA Technical Reports Server (NTRS)

Khattar, Mukesh K.

1989-01-01

A novel application of an air-to-air heat pipe heat exchanger (HPHX) in a cooling and dehumidification process of an air-conditioning system is described which provides significant energy savings in applications requiring reheat of cold supply air to maintain low humidity. The efficiency of the system has been demonstrated in an application requiring a humidity of 40 percent. The use of the HPHX and fine tuning of the air-conditioning system and controls has resulted in significant energy savings. The technology can be advantageously used in many low-humidity applications commonly encountered in high-tech and aerospace facilities.

Actual measurement, hygrothermal response experiment and growth prediction analysis of microbial contamination of central air conditioning system in Dalian, China

PubMed Central

Lv, Yang; Hu, Guangyao; Wang, Chunyang; Yuan, Wenjie; Wei, Shanshan; Gao, Jiaoqi; Wang, Boyuan; Song, Fangchao

2017-01-01

The microbial contamination of central air conditioning system is one of the important factors that affect the indoor air quality. Actual measurement and analysis were carried out on microbial contamination in central air conditioning system at a venue in Dalian, China. Illumina miseq method was used and three fungal samples of two units were analysed by high throughput sequencing. Results showed that the predominant fungus in air conditioning unit A and B were Candida spp. and Cladosporium spp., and two fungus were further used in the hygrothermal response experiment. Based on the data of Cladosporium in hygrothermal response experiment, this paper used the logistic equation and the Gompertz equation to fit the growth predictive model of Cladosporium genera in different temperature and relative humidity conditions, and the square root model was fitted based on the two environmental factors. In addition, the models were carried on the analysis to verify the accuracy and feasibility of the established model equation. PMID:28367963

Actual measurement, hygrothermal response experiment and growth prediction analysis of microbial contamination of central air conditioning system in Dalian, China.

PubMed

Lv, Yang; Hu, Guangyao; Wang, Chunyang; Yuan, Wenjie; Wei, Shanshan; Gao, Jiaoqi; Wang, Boyuan; Song, Fangchao

2017-04-03

The microbial contamination of central air conditioning system is one of the important factors that affect the indoor air quality. Actual measurement and analysis were carried out on microbial contamination in central air conditioning system at a venue in Dalian, China. Illumina miseq method was used and three fungal samples of two units were analysed by high throughput sequencing. Results showed that the predominant fungus in air conditioning unit A and B were Candida spp. and Cladosporium spp., and two fungus were further used in the hygrothermal response experiment. Based on the data of Cladosporium in hygrothermal response experiment, this paper used the logistic equation and the Gompertz equation to fit the growth predictive model of Cladosporium genera in different temperature and relative humidity conditions, and the square root model was fitted based on the two environmental factors. In addition, the models were carried on the analysis to verify the accuracy and feasibility of the established model equation.

Monitoring results and analysis of thermal comfort conditions in experimental buildings for different heating systems and ventilation regimes during heating and cooling seasons

NASA Astrophysics Data System (ADS)

Gendelis, S.; Jakovičs, A.; Ratnieks, J.; Bandeniece, L.

2017-10-01

This paper focuses on the long-term monitoring of thermal comfort and discomfort parameters in five small test buildings equipped with different heating and cooling systems. Calculations of predicted percentage of dissatisfied people (PPD) index and discomfort factors are provided for the room in winter season running three different heating systems - electric heater, air-air heat pump and air-water heat pump, as well as for the summer cooling with split type air conditioning systems. It is shown that the type of heating/cooling system and its working regime has an important impact on thermal comfort conditions in observed room. Recommendations for the optimal operating regimes and choice of the heating system from the thermal comfort point of view are summarized.

Transitioning to Low-GWP Alternatives in Motor Vehicle Air Conditioning Systems

EPA Pesticide Factsheets

This fact sheet provides information on low-GWP alternatives in newly manufactured motor vehicle air conditioning systems. It discusses HFC alternatives, market trends, challenges to market entry for alternatives, and potential solutions.

ACHP | News | ACHP Issues Program Comment for GSA on Select Repairs and

Science.gov Websites

to windows, lighting, roofing, and heating, ventilating, and air-conditioning (HVAC) systems within Upgrades Windows Lighting Roofing Heating, Ventilation, and Air Conditioning (HVAC) Systems Updated March

Solar Absorption Refrigeration System for Air-Conditioning of a Classroom Building in Northern India

NASA Astrophysics Data System (ADS)

Agrawal, Tanmay; Varun; Kumar, Anoop

2015-10-01

Air-conditioning is a basic tool to provide human thermal comfort in a building space. The primary aim of the present work is to design an air-conditioning system based on vapour absorption cycle that utilizes a renewable energy source for its operation. The building under consideration is a classroom of dimensions 18.5 m × 13 m × 4.5 m located in Hamirpur district of Himachal Pradesh in India. For this purpose, cooling load of the building was calculated first by using cooling load temperature difference method to estimate cooling capacity of the air-conditioning system. Coefficient of performance of the refrigeration system was computed for various values of strong and weak solution concentration. In this work, a solar collector is also designed to provide required amount of heat energy by the absorption system. This heat energy is taken from solar energy which makes this system eco-friendly and sustainable. A computer program was written in MATLAB to calculate the design parameters. Results were obtained for various values of solution concentrations throughout the year. Cost analysis has also been carried out to compare absorption refrigeration system with conventional vapour compression cycle based air-conditioners.

Air filtration systems and restrictive access conditions improve indoor air quality in clinical units: Penicillium as a general indicator of hospital indoor fungal levels.

PubMed

Araujo, Ricardo; Cabral, João Paulo; Rodrigues, Acácio Gonçalves

2008-03-01

High-efficiency particulate air (HEPA) filters do not completely prevent nosocomial fungal infections. The first aim of this study was to evaluate the impact of different filters and access conditions upon airborne fungi in hospital facilities. Additionally, this study identified fungal indicators of indoor air concentrations. Eighteen rooms and wards equipped with different air filter systems, and access conditions were sampled weekly, during 16 weeks. Tap water samples were simultaneously collected. The overall mean concentration of atmospheric fungi for all wards was 100 colony forming units/m(3). We found a direct proportionality between the levels of the different fungi in the studied atmospheres. Wards with HEPA filters at positive air flow yielded lower fungal levels. Also, the existence of an anteroom and the use of protective clothes were associated to the lowest fungal levels. Principal component analysis showed that penicillia afforded the best separation between wards' air fungal levels. Fungal strains were rarely recovered from tap water samples. In addition to air filtration systems, some access conditions to hospital units, like presence of anteroom and use of protective clothes, may prevent high fungal air load. Penicillia can be used as a general indicator of indoor air fungal levels at Hospital S. João.

Experimental temperature analysis of simple & hybrid earth air tunnel heat exchanger in series connection at Bikaner Rajasthan India

NASA Astrophysics Data System (ADS)

Jakhar, O. P.; Sharma, Chandra Shekhar; Kukana, Rajendra

2018-05-01

The Earth Air Tunnel Heat Exchanger System is a passive air-conditioning system which has no side effect on earth climate and produces better cooling effect and heating effect comfortable to human body. It produces heating effect in winter and cooling effect in summer with the minimum power consumption of energy as compare to other air-conditioning devices. In this research paper Temperature Analysis was done on the two systems of Earth Air Tunnel Heat Exchanger experimentally for summer cooling purpose. Both the system was installed at Mechanical Engineering Department Government Engineering College Bikaner Rajasthan India. Experimental results concludes that the Average Air Temperature Difference was found as 11.00° C and 16.27° C for the Simple and Hybrid Earth Air Tunnel Heat Exchanger in Series Connection System respectively. The Maximum Air Temperature Difference was found as 18.10° C and 23.70° C for the Simple and Hybrid Earth Air Tunnel Heat Exchanger in Series Connection System respectively. The Minimum Air Temperature Difference was found as 5.20° C and 11.70° C for the Simple and Hybrid Earth Air Tunnel Heat Exchanger in Series Connection System respectively.

Evaluation of Rankine cycle air conditioning system hardware by computer simulation

NASA Technical Reports Server (NTRS)

Healey, H. M.; Clark, D.

1978-01-01

A computer program for simulating the performance of a variety of solar powered Rankine cycle air conditioning system components (RCACS) has been developed. The computer program models actual equipment by developing performance maps from manufacturers data and is capable of simulating off-design operation of the RCACS components. The program designed to be a subroutine of the Marshall Space Flight Center (MSFC) Solar Energy System Analysis Computer Program 'SOLRAD', is a complete package suitable for use by an occasional computer user in developing performance maps of heating, ventilation and air conditioning components.

Capability of air filters to retain airborne bacteria and molds in heating, ventilating and air-conditioning (HVAC) systems.

PubMed

Möritz, M; Peters, H; Nipko, B; Rüden, H

2001-07-01

The capability of air filters (filterclass: F6, F7) to retain airborne outdoor microorganisms was examined in field experiments in two heating, ventilating and air conditioning (HVAC) systems. At the beginning of the 15-month investigation period, the first filter stages of both HVAC systems were equipped with new unused air filters. The number of airborne bacteria and molds before and behind the filters were determined simultaneously in 14 days-intervals using 6-stage Andersen cascade impactors. Under relatively dry (< 80% R. H.) and warm (> 12 degrees C) outdoor air conditions air filters led to a marked reduction of airborne microorganism concentrations (bacteria by approximately 70% and molds by > 80%). However, during long periods of high relative humidity (> 80% R. H.) a proliferation of bacteria on air filters with subsequent release into the filtered air occurred. These microorganisms were mainly smaller than 1.1 microns therefore being part of the respirable fraction. The results showed furthermore that one possibility to avoid microbial proliferation is to limit the relative humidity in the area of the air filters to 80% R. H. (mean of 3 days), e.g. by using preheaters in front of air filters in HVAC-systems.

Design and implementation of an air-conditioning system with storage tank for load shifting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Y.Y.; Wu, C.J.; Liou, K.L.

1987-11-01

The experience with the design, simulation and implementation of an air-conditioning system with chilled water storage tank is presented in this paper. The system is used to shift air-conditioning load of residential and commercial buildings from on-peak to off-peak period. Demand-side load management can thus be achieved if many buildings are equipped with such storage devices. In the design of this system, a lumped-parameter circuit model is first employed to simulate the heat transfer within the air-conditioned building such that the required capacity of the storage tank can be figured out. Then, a set of desirable parameters for the temperaturemore » controller of the system are determined using the parameter plane method and the root locus method. The validity of the proposed mathematical model and design approach is verified by comparing the results obtained from field tests with those from the computer simulations. Cost-benefit analysis of the system is also discussed.« less

Optimal coupling and feasibility of a solar-powered year-round ejector air conditioner

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sokolov, M.; Hershgal, D.

1993-06-01

An ejector refrigeration system that uses a conventional refrigerant (R-114) is introduced as a possible mechanism for providing solar-based air-conditioning. Optimal coupling conditions between the collectors' energy output and energy requirements of the cooling system, are investigated. Operation at such optimal conditions assures maximized overall efficiency. Procedures leading to the evaluation of the performance of a real system are disclosed. Design curves for such a system with R-114 as refrigerant are provided. A multi-ejectors arrangement that provides an efficient adjustment for variations of ambient conditions, is described. Year-round air-conditioning is facilitated by rerouting the refrigerant flow through a heating modemore » of the system. Calculations are carried out for illustrative configurations in which relatively low condensing temperature (water reservoirs, cooling towers, or moderate climate) can be maintained.« less

Bio-Defense Now: 56 Suggestions for Immediate Improvements

DTIC Science & Technology

2005-05-01

Air Education and Training Command HVAC Heating, Ventilation and Air Conditioning ICAM Improved Chemical Agent Monitor ICD-9-CM Internal...conditioning ( HVAC ) system capabilities, making a big difference in removal of many BW agents. High Efficiency Particulate Air (HEPA) filters are also...agents. This program has developed biological sensor-activated heating, ventilation, and air conditioning ( HVAC ) control sys- tems, high efficiency

77 FR 8178 - Test Procedures for Central Air Conditioners and Heat Pumps: Public Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-14

... distribution of those central air conditioning systems and heat pump systems manufactured after January 1, 2010... system central air conditioners and heat pumps be tested using ``the evaporator coil that is likely to... issued two guidance documents surrounding testing central air conditioner and heat pump systems utilizing...

Experimental research on the indoor temperature and humidity fields in radiant ceiling air-conditioning system under natural ventilation

NASA Astrophysics Data System (ADS)

Huang, Tao; Xiang, Yutong; Wang, Yonghong

2017-05-01

In this paper, the indoor temperature and humidity fields of the air in a metal ceiling radiant panel air conditioning system with fresh air under natural ventilation were researched. The temperature and humidity distributions at different height and different position were compared. Through the computation analysis of partial pressure of water vapor, the self-recovery characteristics of humidity after the natural ventilation was discussed.

Energy savings potential in air conditioners and chiller systems

DOE PAGES

Kaya, Durmus; Alidrisi, Hisham

2014-01-22

In the current paper we quantified and evaluated the energy saving potential in air conditioners and chiller systems. Here, we also showed how to reduce the cost of air conditioners and chiller systems in existing facilities on the basis of payback periods. Among the measures investigated were: (1) installing higher efficiency air conditioners, (2) installing higher efficiency chillers, (3) duty cycling air conditioning units, and (4) utilizing existing economizers on air conditioning units. For each method, examples were provided from Arizona, USA. In these examples, the amount of saved energy, the financial evaluation of this energy, and the investment costmore » and pay back periods were calculated.« less

[Biological contamination in office buildings related to ventilation/air conditioning system].

PubMed

Bródka, Karolina; Sowiak, Małgorzata; Kozajda, Anna; Cyprowski, Marcin; Irena, Szadkowska-Stańczyk

2012-01-01

Indoor air is contaminated with microorganisms coming from both the atmospheric air and sources present in premises. The aim of this study was to analyze the concentrations of biological agents in office buildings, dependending on ventilation/air conditioning system and season. The study covered office buildings (different in the system of ventila-tion/air conditioning). Air samples for assessing the levels of inhalable dust, endotoxins and (1-->3)-beta-D-glucans, were taken at the selected stationary points of each building during summer and winter. The air was sampled for 6 h, using portable sets consisting of the GilAir 5 pump and the head filled with a filter of fiber glass. The samples for the presence of airborne bacteria and fungi were collected twice during the day using the impaction method. Average concentrations of inhalable dust, bacteria, fungi, endotoxins and (1-->3)-beta-D-glucans in office premises were 0.09 mg/m3, 6.00 x 10(2) cfu/m3, 4.59 x 10(1) cfu/m3, 0.42 ng/m3 and 3.91 ng/m3, respectively. Higher concentrations of the investigated agents were found in summer. In premises with air conditioning concentrations of airborne fungi, (1-->3)-beta-D-glucans and inhalable dust were significantly lower in winter. In summer the trend was reverse except for (1-->3)-beta-D-glucans. Concentrations of biological agents were affected by the season and the presence of air conditioning. Concentrations of inhalable dust, bacteria, fungi, endotoxins and (1-->3)-beta-D-glucans, observed inside the office buildings, were significantly higher in summer than in winter. The presence of the air conditioning system modified in various ways the levels of biological agents. Its influence was greater on the concentration of fungi and (1-->3)-beta-D-glucans than on that of bacteria and endotoxins.

76 FR 52678 - Buy American Exceptions Under the American Recovery and Reinvestment Act of 2009

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-23

... Housing Authority for the purchase and installation of ductless split air conditioning systems for its... manufactured goods (ductless split air conditioning systems) are not produced in the U.S. in sufficient and...

Performance characteristic of hybrid cooling system based on cooling pad and evaporator

NASA Astrophysics Data System (ADS)

Yoon, J. I.; Son, C. H.; Choi, K. H.; Kim, Y. B.; Sung, Y. H.; Roh, S. J.; Kim, Y. M.; Seol, S. H.

2018-01-01

In South Korea, most of domestic animals such as pigs and chickens might die due to thermal diseases if they are exposed to the high temperature consistently. In order to save them from the heat wave, numerous efforts have been carried out: installing a shade net, adjusting time of feeding, spraying mist and setting up a circulation fan. However, these methods have not shown significant improvements. Thus, this study proposes a hybrid cooling system combining evaporative cooler and air-conditioner in order to resolve the conventional problems caused by the high temperature in the livestock industry. The problem of cooling systems using evaporative cooling pads is that they are not effective for eliminating huge heat load due to their limited capacity. And, temperature of the supplied air cannot be low enough compared to conventional air-conditioning systems. On the other hand, conventional air-conditioning systems require relatively expensive installation cost, and high operating cost compared to evaporative cooling system. The hybrid cooling system makes up for the lack of cooling capacity of the evaporative cooler by employing the conventional air-conditioner. Additionally, temperature of supplied air can be lowered enough. In the hybrid cooling system, induced air by a fan is cooled by the evaporation of water in the cooling pad, and it is cooled again by an evaporator in the air-conditioner. Therefore, the more economical operation is possible due to additionally obtained cooling capacity from the cooling pads. Major results of experimental analysis of hybrid cooling system are as follows. The compressor power consumption of the hybrid cooling system is about 23% lower, and its COP is 17% higher than that of the conventional air-conditioners. Regarding the condition of changing ambient temperature, the total power consumption decreased by about 5% as the ambient temperature changed from 28.7°C to 31.7°C. Cooling capacity and COP also presented about 3% and 1% of minor difference at the same comparison condition.

LINKING ETA MODEL WITH THE COMMUNITY MULTISCALE AIR QUALITY (CMAQ) MODELING SYSTEM: OZONE BOUNDARY CONDITIONS

EPA Science Inventory

A prototype surface ozone concentration forecasting model system for the Eastern U.S. has been developed. The model system is consisting of a regional meteorological and a regional air quality model. It demonstrated a strong prediction dependence on its ozone boundary conditions....

TEWI Evaluation for Refrigeration and Air-Conditioning Systems in Office Buildings with Different Regional Heat Demand

NASA Astrophysics Data System (ADS)

Sobue, Atsushi; Watanabe, Koichi

In the present study, we quantitatively evaluated the global warming impact by refrigeration and air-conditioning systems in office buildings on the basis of reliable TEWI information. This paper proposes an improved TEWI evaluation procedure by considering regional heat demands and part load of air-conditioning systems. In the TEWI evaluation of commercial chillers, a percentage of the impact by refrigerant released to the atmosphere (direct effect) is less than 19.9% in TEWI values. Therefore, a reduction of the impact by CO2 released as a result of the energy consumed to drive the refrigeration or air-conditioning systems through out their lifetime (indirect effect) is the most effective measure in reducing the global warming impact. On the other hand, we have also pointed out energy loss that might be generated by an excess investment to the equipment. We have also showed a usefulness in dividing the heating / cooling system into several small-capacity units so as to improve the energy utilization efficiency.

Exposure of Mammalian Cells to Air-Pollutant Mixtures at the Air-Liquid Interface

EPA Science Inventory

It has been widely accepted that exposure of mammalian cells to air-pollutant mixtures at the air-liquid interface is a more realistic approach than exposing cell under submerged conditions. The VITROCELL systems, are commercially available systems for air-liquid interface expo...

Colonization by Cladosporium spp. of painted metal surfaces associated with heating and air conditioning systems

NASA Technical Reports Server (NTRS)

Ahearn, D. G.; Simmons, R. B.; Switzer, K. F.; Ajello, L.; Pierson, D. L.

1991-01-01

Cladosporium cladosporioides and C. hebarum colonized painted metal surfaces of covering panels and register vents of heating, air conditioning and ventilation systems. Hyphae penetrated the paint film and developed characteristic conidiophores and conidia. The colonies were tightly appressed to the metal surface and conidia were not readily detectable via standard air sampling procedures.

High Efficiency Variable Speed Versatile Power Air Conditioning System for Military Vehicles

DTIC Science & Technology

2013-08-01

MOBILITY (P&M) MINI-SYMPOSIUM AUGUST 21-22, 2013 - TROY , MICHIGAN High efficiency variable speed versatile power air conditioning system for...power draw was measured using a calibrated Watt meter. The schematic of the setup is shown in Figure 5 and the setup is shown in Figure 6. Figure...Rocky Research environmental chamber. Cooling Capacity was directly measured in Btu/hr or Watts via measuring the Air flow velocity and the air

Thermal conditions and perceived air quality in an air-conditioned auditorium

NASA Astrophysics Data System (ADS)

Polednik, Bernard; Guz, Łukasz; Skwarczyński, Mariusz; Dudzińska, Marzenna R.

2016-07-01

The study reports measurements of indoor air temperature (T) and relative humidity (RH), perceived air quality (PAQ) and CO2, fine aerosol particle number (PN) and mass (PM1) concentrations in an air conditioned auditorium. The measurements of these air physical parameters have been carried out in the unoccupied auditorium with the air conditioning system switched off (AC off mode) and in the unoccupied and occupied auditorium with the air conditioning system switched off during the night and switched on during the day (AC on/off mode). The average indoor air thermal parameters, CO2 concentration and the PAQ value (in decipols) were elevated, while average PM1 concentration was lower in the AC on/off mode. A statistically significant (p < 0.001) positive correlation has been observed between T and PAQ values and CO2 concentrations (r = 0.66 and r = 0.59, respectively) in that AC mode. A significant negative correlation has been observed between T and PN and PM1 concentrations (r = -0.38 and r = -0.49, respectively). In the AC off mode the above relations between T and the particle concentrations were not that unequivocal. These findings may be of importance as they indicate that in certain AC operation modes the indoor air quality deteriorates along with the variation of the indoor air microclimate and room occupation. This, in turn, may adversely affect the comfort and productivity of the users of air conditioned premises.

The influence of air-conditioning on street temperatures in the city of Paris

NASA Astrophysics Data System (ADS)

de Munck, C. S.; Pigeon, G.; Masson, V.; Marchadier, C.; Meunier, F.; Tréméac, B.; Merchat, M.

2010-12-01

A consequence of urban heat islands in summer is the increased use of air-conditioning during extreme heat events : the use of air-conditioning systems, while cooling the inside of buildings releases waste heat (as latent and sensible heat) in the lower part of the urban atmosphere, hence potentially increasing air street temperatures where the heat is released. This may lead locally to a further increase in air street temperatures, therefore increasing the air cooling demand, while at the same time lowering the efficiency of air-conditioning units. A coupled model consisting of a meso-scale meteorological model (MESO-NH) and an urban energy balance model (TEB) has been implemented with an air-conditioning module and used in combination to real spatialised datasets to understand and quantify potential increases in temperature due to air-conditioning heat releases for the city of Paris . In a first instance, the current types of air-conditioning systems co-existing in the city were simulated (underground chilled water network, wet cooling towers and individual air-conditioning units) to study the effects of latent and sensible heat releases on street temperatures. In a third instance, 2 scenarios were tested to characterise the impacts of likely future trends in air-conditioning equipment in the city : a first scenario for which current heat releases were converted to sensible heat, and a second based on 2030s projections of air-conditioning equipment at the scale of the city. All the scenarios showed an increase in street temperature which, as expected, was greater at night time than day time. For the first two scenarios, this increase in street temperatures was localised at or near the sources of air-conditioner heat releases, while the 2030s air-conditioning scenario impacted wider zones in the city. The amplitude of the increase in temperature varied from 0,25°C to 1°C for the air-conditioning current state, between 0,25°C and 2°C for the sensible heat release only scenario, and finally from 0,25°C to 2 °C for the 2030s scenario, with impacts of up to 3°C locally. Overall, these results demonstrated to which extend the use air-conditioning could enhance street temperatures in the city of Paris and the importance of a spatialised approach.

Summarized Data of Test Space Heating, Ventilation and Air Conditioning Inspections from the Building Assessment Survey and Evaluation Study

EPA Pesticide Factsheets

Information on the characteristics of the heating, ventilation, and air conditioning (HVAC) system(s) in the entire BASE building including types of ventilation, equipment configurations, and operation and maintenance issues

21. DETAIL OF AIR HANDLER 1 (MST AIRCONDITIONING SYSTEM) INTERIOR, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. DETAIL OF AIR HANDLER 1 (MST AIR-CONDITIONING SYSTEM) INTERIOR, SOUTHEAST CORNER, STATION 30, SLC-3W MST - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

A problem of hospital hygiene: the presence of aspergilli in hospital wards with different air-conditioning features.

PubMed

Perdelli, Fernanda; Sartini, Marina; Spagnolo, Anna Maria; Dallera, Maurizio; Lombardi, Roberto; Cristina, Maria Luisa

2006-06-01

A total of 1,030 microbiological samples were taken in 3 hospital wards with different air-conditioning features: no conditioning system (ward A), a conditioning system equipped with minimum efficiency reporting value (MERV) filters (ward B), and a conditioning system thoroughly maintained and equipped with high-efficiency particulate air (HEPA) filters (absolute) (ward C). The air in each ward was sampled, and the bacterial and fungal concentrations were determined by active and passive methods. The concentration of fungi on surfaces was also determined. Active sampling showed positive samples in wards A and B only, with average values of 0.50 colony-forming units (CFU)/m(3) (95% CI, 0.30 to 0.70) in A and 0.16 CFU/m(3) (95% CI, 0.13 to 0.20) in B. Passive sampling was positive only in ward A (mean, 0.14 CFU/cm(2)/h; 95% CI, 0.13 to 0.15). Aspergillus was found in 27% and 22% of sampled surfaces in wards A and B, respectively, but in no samples from ward C. The most commonly found species was A. fumigatus (76% of cases in A and 34% of cases in B). The results show that the use of air-conditioning systems markedly reduces the concentration of aspergilli in the environment. Proper maintenance of these systems is clearly fundamental if their efficacy is to be ensured.

Tests of a High Temperature Sample Conditioner for the Waste Treatment Plant LV-S2, LV-S3, HV-S3A and HV-S3B Exhaust Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flaherty, Julia E.; Glissmeyer, John A.

2015-03-18

Tests were performed to evaluate a sample conditioning unit for stack monitoring at Hanford Tank Waste Treatment and Immobilization Plant (WTP) exhaust stacks with elevated air temperatures. The LV-S2, LV-S3, HV-S3A and HV-S3B exhaust stacks are expected to have elevated air temperature and dew point. At these emission points, exhaust temperatures are too high to deliver the air sample directly to the required stack monitoring equipment. As a result, a sample conditioning system is considered to cool and dry the air prior to its delivery to the stack monitoring system. The method proposed for the sample conditioning is a dilutionmore » system that will introduce cooler, dry air to the air sample stream. This method of sample conditioning is meant to reduce the sample temperature while avoiding condensation of moisture in the sample stream. An additional constraint is that the ANSI/HPS N13.1-1999 standard states that at least 50% of the 10 μm aerodynamic diameter (AD) particles present in the stack free stream must be delivered to the sample collector. In other words, depositional loss of particles should be limited to 50% in the sampling, transport, and conditioning systems. Based on estimates of particle penetration through the LV-S3 sampling system, the diluter should perform with about 80% penetration or better to ensure that the total sampling system passes the 50% or greater penetration criterion.« less

14 CFR 27.1091 - Air induction.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating conditions...

14 CFR 27.1091 - Air induction.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating conditions...

14 CFR 27.1091 - Air induction.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating conditions...

14 CFR 27.1091 - Air induction.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating conditions...

14 CFR 27.1091 - Air induction.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Air induction. 27.1091 Section 27.1091... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Induction System § 27.1091 Air induction. (a) The air induction system for each engine must supply the air required by that engine under the operating conditions...

The Effect of Air-Conditioning on Student and Teacher Performance.

ERIC Educational Resources Information Center

Phoenix Union High School District, AZ. Dept. of Research and Planning.

The literature is reviewed to see if research shows a relationship between student and teacher performance and air conditioning of classrooms. The benefits of air conditioning in promoting learning are substantiated by studies that are summarized but not cited. The relationship of the report to the Phoenix Union High School System Advisory…

40 CFR 86.166-12 - Method for calculating emissions due to air conditioning leakage.

Code of Federal Regulations, 2012 CFR

2012-07-01

... determine a refrigerant leakage rate in grams per year from vehicle-based air conditioning units. The... using the following equation: Grams/YRTOT = Grams/YRRP + Grams/YRSP + Grams/YRFH + Grams/YRMC + Grams/YRC Where: Grams/YRTOT = Total air conditioning system emission rate in grams per year and rounded to...

76 FR 25705 - Buy American Exceptions Under the American Recovery and Reinvestment Act of 2009

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-05

... the basis that the relevant manufactured goods (through-the-wall air conditioning systems) are not..., PA, for the purchase and installation of through-the-wall air-conditioning units for the Frank... the purchase and installation of a ductless split air conditioning unit at the Colleen Loney Manor...

Air Conditioning. FOS: Fundamentals of Service.

ERIC Educational Resources Information Center

Employment and Training Administration (DOL), Washington, DC. Office of Youth Programs.

This manual on air conditioning is one of a series of power mechanics texts and visual aids covering theory of operation, diagnosis, and repair. Information is presented for use by vocational students and teachers as well as shop servicemen and laymen. Focus is on air conditioning systems for mobile machines, but most of the information also…

40 CFR 86.1866-12 - CO2 fleet average credit programs.

Code of Federal Regulations, 2010 CFR

2010-07-01

... technologies designed to reduce air conditioning refrigerant leakage over the useful life of their passenger... implementing specific air conditioning system technologies designed to reduce air conditioning-related CO2... than 10% when compared to previous industry standard designs): 1.1 g/mi. (viii) Oil separator: 0.6 g/mi...

40 CFR 86.1866-12 - CO2 fleet average credit programs.

Code of Federal Regulations, 2011 CFR

2011-07-01

... technologies designed to reduce air conditioning refrigerant leakage over the useful life of their passenger... implementing specific air conditioning system technologies designed to reduce air conditioning-related CO2... than 10% when compared to previous industry standard designs): 1.1 g/mi. (viii) Oil separator: 0.6 g/mi...

Combined comfort model of thermal comfort and air quality on buses in Hong Kong.

PubMed

Shek, Ka Wing; Chan, Wai Tin

2008-01-25

Air-conditioning settings are important factors in controlling the comfort of passengers on buses. The local bus operators control in-bus air quality and thermal environment by conforming to the prescribed levels stated in published standards. As a result, the settings are merely adjusted to fulfill the standards, rather than to satisfy the passengers' thermal comfort and air quality. Such "standard-oriented" practices are not appropriate; the passengers' preferences and satisfaction should be emphasized instead. Thus a "comfort-oriented" philosophy should be implemented to achieve a comfortable in-bus commuting environment. In this study, the achievement of a comfortable in-bus environment was examined with emphasis on thermal comfort and air quality. Both the measurement of physical parameters and subjective questionnaire surveys were conducted to collect practical in-bus thermal and air parameters data, as well as subjective satisfaction and sensation votes from the passengers. By analyzing the correlation between the objective and subjective data, a combined comfort models were developed. The models helped in evaluating the percentage of dissatisfaction under various combinations of passengers' sensation votes towards thermal comfort and air quality. An effective approach integrated the combined comfort model, hardware and software systems and the bus air-conditioning system could effectively control the transient in-bus environment. By processing and analyzing the data from the continuous monitoring system with the combined comfort model, air-conditioning setting adjustment commands could be determined and delivered to the hardware. This system adjusted air-conditioning settings depending on real-time commands along the bus journey. Therefore, a comfortable in-bus air quality and thermal environment could be achieved and efficiently maintained along the bus journey despite dynamic outdoor influences. Moreover, this model can help optimize air-conditioning control by striking a beneficial balance between energy conservation and passengers' satisfaction level.

Increasing EDV Range through Intelligent Cabin Air Handling Strategies: Annual Progress Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leighton, Daniel; Rugh, John

Computational fluid dynamics (CFD) simulations of a Ford Focus Electric demonstrated that a split flow heating, ventilating and air conditioning (HVAC) system with rear recirculation ducts can reduce cabin heating loads by up to 57.4% relative to full fresh air usage under some conditions (steady state, four passengers, ambient temperature of -5 deg C). Simulations also showed that implementing a continuous recirculation fraction control system into the original equipment manufacturer (OEM) HVAC system can reduce cabin heating loads by up to 50.0% relative to full fresh air usage under some conditions (steady state, four passengers, ambient temperature of -5 degmore » C). Identified that continuous fractional recirculation control of the OEM system can provide significant energy savings for EVs at minimal additional cost, while a split flow HVAC system with rear recirculation ducts only provides minimal additional improvement at significant additional cost.« less

Practical Guide to HVAC for Schools.

ERIC Educational Resources Information Center

ASHRAE Journal, 1998

1998-01-01

Features six articles on heating, ventilation, and air-conditioning systems for schools. Examines how to avoid air temperature complaints when choosing a system; special system features; engineers, indoor air quality, and schools; mechanical systems noise in classrooms; operation and management issues related to design; and details on bids and…

Technology evaluation of heating, ventilation, and air conditioning for MIUS application

NASA Technical Reports Server (NTRS)

Gill, W. L.; Keough, M. B.; Rippey, J. O.

1974-01-01

Potential ways of providing heating, ventilation, and air conditioning for a building complex serviced by a modular integrated utility system (MIUS) are examined. Literature surveys were conducted to investigate both conventional and unusual systems to serve this purpose. The advantages and disadvantages of the systems most compatible with MIUS are discussed.

Particulate matter in animal rooms housing mice in microisolation caging.

PubMed

Langham, Gregory L; Hoyt, Robert F; Johnson, Thomas E

2006-11-01

Reactions to allergens created by laboratory animals are among the most frequently encountered occupational illnesses associated with research animals. Personnel are exposed to these allergens through airborne particulate matter. Although the use of microisolation caging systems can reduce particulate matter concentrations in rooms housing mice, the operating parameters of ventilated caging systems vary extensively. We compared room air in mouse rooms containing 5 different types of caging: 1) individually ventilated caging under positive pressure with filtered intake air and exhaust air returned to the room (VCR+), 2) individually ventilated caging under negative pressure with exhaust air returned to the room (VCR-), 3) individually ventilated caging under positive pressure with exhaust air returned to the heating, ventilation, and air-conditioning (HVAC) system, 4) individually ventilated caging under negative pressure with exhaust air returned to the HVAC system, and 5) static microisolation cages. We found that rooms under VCR conditions had fewer large particles than did those under other conditions, but the numbers of 0.3 microm particles did not differ significantly among systems. Static, positive or negative pressure applied to caging units as well as route of air exhaust were found to have little influence on the total number of particles in the atmosphere. Therefore, considering the heat load, odor, and overall particulate concentration in the room, placing individually ventilated caging under negative pressure with exhaust air returned to the HVAC system appears to be the optimal overall choice when using microisolation housing for rodents.

System and method of providing quick thermal comfort with reduced energy by using directed spot conditioning

DOEpatents

Wang, Mingyu; Kadle, Prasad S.; Ghosh, Debashis; Zima, Mark J.; Wolfe, IV, Edward; Craig, Timothy D

2016-10-04

A heating, ventilation, and air conditioning (HVAC) system and a method of controlling a HVAC system that is configured to provide a perceived comfortable ambient environment to an occupant seated in a vehicle cabin. The system includes a nozzle configured to direct an air stream from the HVAC system to the location of a thermally sensitive portion of the body of the occupant. The system also includes a controller configured to determine an air stream temperature and an air stream flow rate necessary to establish the desired heat supply rate for the sensitive portion and provide a comfortable thermal environment by thermally isolating the occupant from the ambient vehicle cabin temperature. The system may include a sensor to determine the location of the sensitive portion. The nozzle may include a thermoelectric device to heat or cool the air stream.

Noncontact Monitoring of Respiration by Dynamic Air-Pressure Sensor.

PubMed

Takarada, Tohru; Asada, Tetsunosuke; Sumi, Yoshihisa; Higuchi, Yoshinori

2015-01-01

We have previously reported that a dynamic air-pressure sensor system allows respiratory status to be visually monitored for patients in minimally clothed condition. The dynamic air-pressure sensor measures vital information using changes in air pressure. To utilize this device in the field, we must clarify the influence of clothing conditions on measurement. The present study evaluated use of the dynamic air-pressure sensor system as a respiratory monitor that can reliably detect change in breathing patterns irrespective of clothing. Twelve healthy volunteers reclined on a dental chair positioned horizontally with the sensor pad for measuring air-pressure signals corresponding to respiration placed on the seat back of the dental chair in the central lumbar region. Respiratory measurements were taken under 2 conditions: (a) thinly clothed (subject lying directly on the sensor pad); and (b) thickly clothed (subject lying on the sensor pad covered with a pressure-reducing sheet). Air-pressure signals were recorded and time integration values for air pressure during each expiration were calculated. This information was compared with expiratory tidal volume measured simultaneously by a respirometer connected to the subject via face mask. The dynamic air-pressure sensor was able to receive the signal corresponding to respiration regardless of clothing conditions. A strong correlation was identified between expiratory tidal volume and time integration values for air pressure during each expiration for all subjects under both clothing conditions (0.840-0.988 for the thinly clothed condition and 0.867-0.992 for the thickly clothed condition). These results show that the dynamic air-pressure sensor is useful for monitoring respiratory physiology irrespective of clothing.

Possible Economies in Air-Conditioning by Accepting Temperature Swings.

ERIC Educational Resources Information Center

Loudon, A. G.; Petherbridge, P.

Public building air conditioning systems, which use constant and varying heat and cooling loads, are compared and investigated. Experiments indicated that constant temperature controls based on outside air temperature alone were inefficient. Ventilating a building with outside air and the methods of doing so are cited as being the most economical…

Calibration of NASA Turbulent Air Motion Measurement System

NASA Technical Reports Server (NTRS)

Barrick, John D. W.; Ritter, John A.; Watson, Catherine E.; Wynkoop, Mark W.; Quinn, John K.; Norfolk, Daniel R.

1996-01-01

A turbulent air motion measurement system (TAMMS) was integrated onboard the Lockheed 188 Electra airplane (designated NASA 429) based at the Wallops Flight Facility in support of the NASA role in global tropospheric research. The system provides air motion and turbulence measurements from an airborne platform which is capable of sampling tropospheric and planetary boundary-layer conditions. TAMMS consists of a gust probe with free-rotating vanes mounted on a 3.7-m epoxy-graphite composite nose boom, a high-resolution inertial navigation system (INS), and data acquisition system. A variation of the tower flyby method augmented with radar tracking was implemented for the calibration of static pressure position error and air temperature probe. Additional flight calibration maneuvers were performed remote from the tower in homogeneous atmospheric conditions. System hardware and instrumentation are described and the calibration procedures discussed. Calibration and flight results are presented to illustrate the overall ability of the system to determine the three-component ambient wind fields during straight and level flight conditions.

The air-conditioning capacity of the human nose.

PubMed

Naftali, Sara; Rosenfeld, Moshe; Wolf, Michael; Elad, David

2005-04-01

The nose is the front line defender of the respiratory system. Unsteady simulations in three-dimensional models have been developed to study transport patterns in the human nose and its overall air-conditioning capacity. The results suggested that the healthy nose can efficiently provide about 90% of the heat and the water fluxes required to condition the ambient inspired air to near alveolar conditions in a variety of environmental conditions and independent of variations in internal structural components. The anatomical replica of the human nose showed the best performance and was able to provide 92% of the heating and 96% of the moisture needed to condition the inspired air to alveolar conditions. A detailed analysis explored the relative contribution of endonasal structural components to the air-conditioning process. During a moderate breathing effort, about 11% reduction in the efficacy of nasal air-conditioning capacity was observed.

Comparative study on the reactivity of Fe/Cu bimetallic particles and zero valent iron (ZVI) under different conditions of N2, air or without aeration.

PubMed

Xiong, Zhaokun; Lai, Bo; Yang, Ping; Zhou, Yuexi; Wang, Juling; Fang, Shuping

2015-10-30

In order to further compare the degradation capacity of Fe(0) and Fe/Cu bimetallic system under different aeration conditions, the mineralization of PNP under different aeration conditions has been investigated thoroughly. The results show that the removal of PNP by Fe(0) or Fe/Cu system followed the pseudo-first-order reaction kinetics. Under the optimal conditions, the COD removal efficiencies obtained through Fe(0) or Fe/Cu system under different aeration conditions followed the trend that Fe/Cu (air)>Fe/Cu (N2: 0-30 min, air: 30-120 min)>control-Fe (air)>Fe/Cu (without aeration)>Fe/Cu (N2)>control-Fe (N2). It revealed that dissolved oxygen (DO) could improve the mineralization of PNP, and Cu could enhance the reactivity of Fe(0). In addition, the degradation of PNP was further analyzed by using UV-vis, FTIR and GC/MS, and the results suggest that Fe/Cu bimetallic system with air aeration could completely break the benzene ring and NO2 structure of PNP and could generate the nontoxic and biodegradable intermediate products. Meanwhile, most of these intermediate products were further mineralized into CO2 and H2O, which brought about a high COD removal efficiency (83.8%). Therefore, Fe/Cu bimetallic system with air aeration would be a promising process for toxic refractory industry wastewater. Copyright © 2015 Elsevier B.V. All rights reserved.

Reduced bleed air extraction for DC-10 cabin air conditioning

NASA Technical Reports Server (NTRS)

Newman, W. H.; Viele, M. R.; Hrach, F. J.

1980-01-01

It is noted that a significant fuel savings can be achieved by reducing bleed air used for cabin air conditioning. Air in the cabin can be recirculated to maintain comfortable ventilation rates but the quality of the air tends to decrease due to entrainment of smoke and odors. Attention is given to a development system designed and fabricated under the NASA Engine Component Improvement Program to define the recirculation limit for the DC-10. It is shown that with the system, a wide range of bleed air reductions and recirculation rates is possible. A goal of 0.8% fuel savings has been achieved which results from a 50% reduction in bleed extraction from the engine.

Effects of anthropogenic heat due to air-conditioning systems on an extreme high temperature event in Hong Kong

NASA Astrophysics Data System (ADS)

Wang, Y.; Li, Y.; Di Sabatino, S.; Martilli, A.; Chan, P. W.

2018-03-01

Anthropogenic heat flux is the heat generated by human activities in the urban canopy layer, which is considered the main contributor to the urban heat island (UHI). The UHI can in turn increase the use and energy consumption of air-conditioning systems. In this study, two effective methods for water-cooling air-conditioning systems in non-domestic areas, including the direct cooling system and central piped cooling towers (CPCTs), are physically based, parameterized, and implemented in a weather research and forecasting model at the city scale of Hong Kong. An extreme high temperature event (June 23-28, 2016) in the urban areas was examined, and we assessed the effects on the surface thermal environment, the interaction of sea-land breeze circulation and urban heat island circulation, boundary layer dynamics, and a possible reduction of energy consumption. The results showed that both water-cooled air-conditioning systems could reduce the 2 m air temperature by around 0.5 °C-0.8 °C during the daytime, and around 1.5 °C around 7:00-8:00 pm when the planetary boundary layer (PBL) height was confined to a few hundred meters. The CPCT contributed around 80%-90% latent heat flux and significantly increased the water vapor mixing ratio in the atmosphere by around 0.29 g kg-1 on average. The implementation of the two alternative air-conditioning systems could modify the heat and momentum of turbulence, which inhibited the evolution of the PBL height (a reduction of 100-150 m), reduced the vertical mixing, presented lower horizontal wind speed and buoyant production of turbulent kinetic energy, and reduced the strength of sea breeze and UHI circulation, which in turn affected the removal of air pollutants. Moreover, the two alternative air-conditioning systems could significantly reduce the energy consumption by around 30% during extreme high temperature events. The results of this study suggest potential UHI mitigation strategies and can be extended to other megacities to enable them to be more resilient to UHI effects.

Heating, ventilation and air conditioning system optimization: a study of the effect of climate, building design, system selection and control strategy on the energy consumption of a typical office building in London and Athens

NASA Astrophysics Data System (ADS)

Spasis, Georgios

The increasing demand for air conditioning in commercial buildings imposes a serious threat to Europe's CO2 reduction targets. Architects and engineers are therefore in a key position to help reduce the impact of buildings on the environment by taking appropriate decisions concerning the design of the building and the associated heating, ventilation and air conditioning (HVAC) system. The thesis studies the effect of a number of building and HVAC system related design factors on the energy performance of a notional air-conditioned office building employing either a variable air volume (VAV) system with terminal re-heaters, or a four-pipe fan coil unit (FCU) system with fresh air supply from a central plant, using mainly a dynamic simulation tool and the response surface methodology. The evaluation of the energy performance of the HVAC systems is for two types of climate, using typical weather data for London (UK) and Athens (Greece). It has been found that the design variables associated with the solar radiation through the transparent building elements and the internal heat gains should be the main concern of the building designer. On the other hand, the HVAC system engineer should give emphasis to the parameters associated with the plant performance and operation, as well as the temperature control set-points. It has been shown that it is possible to reduce the carbon emissions of the base case scenario by up to 88% depending on the HVAC system and the climate for which it is simulated. The carbon savings, however, are reduced by up to 22% where humidification is provided. This reduction differs depending on the HVAC system and the climatic conditions. The VAV system is more energy efficient than the FCU system, mainly due to the exploitation of the free cooling capacity of the outdoor air. The difference in carbon emissions between the two systems drops when both of them are simulated for the Athens as opposed to the London typical weather conditions. It has been found that it is possible to turn the carbon scales in favour of the FCU system when humidification to a high RH set-point is provided throughout the year, since the adjustment of the RH of the air is particularly energy wasteful for the VAV system.

Impact of the electric compressor for automotive air conditioning system on fuel consumption and performance analysis

NASA Astrophysics Data System (ADS)

Zulkifli, A. A.; Dahlan, A. A.; Zulkifli, A. H.; Nasution, H.; Aziz, A. A.; Perang, M. R. M.; Jamil, H. M.; Misseri, M. N.

2015-12-01

Air conditioning system is the biggest auxiliary load in a vehicle where the compressor consumed the largest. Problem with conventional compressor is the cooling capacity cannot be control directly to fulfill the demand of thermal load inside vehicle cabin. This study is conducted experimentally to analyze the difference of fuel usage and air conditioning performance between conventional compressor and electric compressor of the air conditioning system in automobile. The electric compressor is powered by the car battery in non-electric vehicle which the alternator will recharge the battery. The car is setup on a roller dynamometer and the vehicle speed is varied at 0, 30, 60, 90 and 110 km/h at cabin temperature of 25°C and internal heat load of 100 and 400 Watt. The results shows electric compressor has better fuel consumption and coefficient of performance compared to the conventional compressor.

[MICROCLIMATE CONDITION IN SUBWAY CARS IN THE SUMMER PERIOD OF THE YEAR].

PubMed

Leksin, A G; Evlampieva, M N; Timoshenkova, E V; Morgunov, A V; Kaptsov, V A

2015-01-01

There are presented the results of the work, which aims to identify the relationship between the temperature of air in the salons of subway cars from the heat output of passengers in different people occupancy of cars during "peak hours", and to determine the efficacy offorced air handling regular ventilation or air conditioning system to remove the elevated heat load on passengers. In the work there was used the method of calculating the amount of heat output of 215 passengers (nominal fullness of the chamber) and the simulation method of heat and moisture output of the same number of passengers. The operating system of ventilation has been shown to fail to decline the average temperature of the air in the passenger compartment to the optimum values and most efficient approach for the reducing the heat load on the passengers is the use of air conditioning systems.

System and method for conditioning intake air to an internal combustion engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sellnau, Mark C.

A system for conditioning the intake air to an internal combustion engine includes a means to boost the pressure of the intake air to the engine and a liquid cooled charge air cooler disposed between the output of the boost means and the charge air intake of the engine. Valves in the coolant system can be actuated so as to define a first configuration in which engine cooling is performed by coolant circulating in a first coolant loop at one temperature, and charge air cooling is performed by coolant flowing in a second coolant loop at a lower temperature. Themore » valves can be actuated so as to define a second configuration in which coolant that has flowed through the engine can be routed through the charge air cooler. The temperature of intake air to the engine can be controlled over a wide range of engine operation.« less

Smart grid integration of small-scale trigeneration systems

NASA Astrophysics Data System (ADS)

Vacheva, Gergana; Kanchev, Hristiyan; Hinov, Nikolay

2017-12-01

This paper presents a study on the possibilities for implementation of local heating, air-conditioning and electricity generation (trigeneration) as distributed energy resource in the Smart Grid. By the means of microturbine-based generators and absorption chillers buildings are able to meet partially or entirely their electrical load curve or even supply power to the grid by following their heating and air-conditioning daily schedule. The principles of small-scale cooling, heating and power generation systems are presented at first, then the thermal calculations of an example building are performed: the heat losses due to thermal conductivity and the estimated daily heating and air-conditioning load curves. By considering daily power consumption curves and weather data for several winter and summer days, the heating/air-conditioning schedule is estimated and the available electrical energy from a microturbine-based cogeneration system is estimated. Simulation results confirm the potential of using cogeneration and trigeneration systems for local distributed electricity generation and grid support in the daily peaks of power consumption.

One-man electrochemical air revitalization system evaluation

NASA Technical Reports Server (NTRS)

Schbert, F. H.; Marshall, R. D.; Hallick, T. M.; Woods, R. R.

1976-01-01

A program to evaluate the performance of a one man capacity, self contained electrochemical air revitalization system was successfully completed. The technology readiness of this concept was demonstrated by characterizing the performance of this one man system over wide ranges in cabin atmospheric conditions. The electrochemical air revitalization system consists of a water vapor electrolysis module to generate oxygen from water vapor in the cabin air, and an electrochemical depolarized carbon dioxide concentrator module to remove carbon dioxide from the cabin air. A control/monitor instrumentation package that uses the electrochemical depolarized concentrator module power generated to partially offset the water vapor electrolysis module power requirements and various structural fluid routing components are also part of the system. The system was designed to meet the one man metabolic oxygen generation and carbon dioxide removal requirements, thereby controlling cabin partial pressure of oxygen at 22 kN/sq m and cabin pressure of carbon dioxide at 400 N/sq m over a wide range in cabin air relative humidity conditions.

Air regenerating and conditioning

NASA Technical Reports Server (NTRS)

Grishayenkov, B. G.

1975-01-01

Various physicochemical methods of regenerating and conditioning air for spacecraft are described with emphasis on conditions which affect efficiency of the system. Life support systems used in closed, hermetically sealed environments are discussed with references to actual application in the Soviet Soyuz and Voskhod manned spacecraft. Temperature and humidity control, removal of carbon dioxide, oxygen regeneration, and removal of bacteria and viruses are among the factors considered.

Effects of oxygen partial pressure on Li-air battery performance

NASA Astrophysics Data System (ADS)

Kwon, Hyuk Jae; Lee, Heung Chan; Ko, Jeongsik; Jung, In Sun; Lee, Hyun Chul; Lee, Hyunpyo; Kim, Mokwon; Lee, Dong Joon; Kim, Hyunjin; Kim, Tae Young; Im, Dongmin

2017-10-01

For application in electric vehicles (EVs), the Li-air battery system needs an air intake system to supply dry oxygen at controlled concentration and feeding rate as the cathode active material. To facilitate the design of such air intake systems, we have investigated the effects of oxygen partial pressure (≤1 atm) on the performance of the Li-air cell, which has not been systematically examined. The amounts of consumed O2 and evolved CO2 from the Li-air cell are measured with a custom in situ differential electrochemical gas chromatography-mass spectrometry (DEGC-MS). The amounts of consumed O2 suggest that the oxygen partial pressure does not affect the reaction mechanism during discharge, and the two-electron reaction occurs under all test conditions. On the other hand, the charging behavior varies by the oxygen partial pressure. The highest O2 evolution ratio is attained under 70% O2, along with the lowest CO2 evolution. The cell cycle life also peaks at 70% O2 condition. Overall, an oxygen partial pressure of about 0.5-0.7 atm maximizes the Li-air cell capacity and stability at 1 atm condition. The findings here indicate that the appropriate oxygen partial pressure can be a key factor when developing practical Li-air battery systems.

Verification of Energy Reduction Effect through Control Optimization of Supply Air Temperature in VRF-OAP System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Je; Yoon, Hyun; Im, Piljae

This paper developed an algorithm that controls the supply air temperature in the variable refrigerant flow (VRF), outdoor air processing unit (OAP) system, according to indoor and outdoor temperature and humidity, and verified the effects after applying the algorithm to real buildings. The VRF-OAP system refers to a heating, ventilation, and air conditioning (HVAC) system to complement a ventilation function, which is not provided in the VRF system. It is a system that supplies air indoors by heat treatment of outdoor air through the OAP, as a number of indoor units and OAPs are connected to the outdoor unit inmore » the VRF system simultaneously. This paper conducted experiments with regard to changes in efficiency and the cooling capabilities of each unit and system according to supply air temperature in the OAP using a multicalorimeter. Based on these results, an algorithm that controlled the temperature of the supply air in the OAP was developed considering indoor and outdoor temperatures and humidity. The algorithm was applied in the test building to verify the effects of energy reduction and the effects on indoor temperature and humidity. Loads were then changed by adjusting the number of conditioned rooms to verify the effect of the algorithm according to various load conditions. In the field test results, the energy reduction effect was approximately 15–17% at a 100% load, and 4–20% at a 75% load. However, no significant effects were shown at a 50% load. The indoor temperature and humidity reached a comfortable level.« less

Verification of Energy Reduction Effect through Control Optimization of Supply Air Temperature in VRF-OAP System

DOE PAGES

Lee, Je; Yoon, Hyun; Im, Piljae; ...

2017-12-27

This paper developed an algorithm that controls the supply air temperature in the variable refrigerant flow (VRF), outdoor air processing unit (OAP) system, according to indoor and outdoor temperature and humidity, and verified the effects after applying the algorithm to real buildings. The VRF-OAP system refers to a heating, ventilation, and air conditioning (HVAC) system to complement a ventilation function, which is not provided in the VRF system. It is a system that supplies air indoors by heat treatment of outdoor air through the OAP, as a number of indoor units and OAPs are connected to the outdoor unit inmore » the VRF system simultaneously. This paper conducted experiments with regard to changes in efficiency and the cooling capabilities of each unit and system according to supply air temperature in the OAP using a multicalorimeter. Based on these results, an algorithm that controlled the temperature of the supply air in the OAP was developed considering indoor and outdoor temperatures and humidity. The algorithm was applied in the test building to verify the effects of energy reduction and the effects on indoor temperature and humidity. Loads were then changed by adjusting the number of conditioned rooms to verify the effect of the algorithm according to various load conditions. In the field test results, the energy reduction effect was approximately 15–17% at a 100% load, and 4–20% at a 75% load. However, no significant effects were shown at a 50% load. The indoor temperature and humidity reached a comfortable level.« less

Evaluation of fuel preparation systems for lean premixing-prevaporizing combustors

NASA Technical Reports Server (NTRS)

Dodds, W. J.; Ekstedt, E. E.

1985-01-01

A series of experiments was carried out in order to produce design data for a premixing prevaporizing fuel-air mixture preparation system for aircraft gas turbine engine combustors. The fuel-air mixture uniformity of four different system design concepts was evaluated over a range of conditions representing the cruise operation of a modern commercial turbofan engine. Operating conditions including pressure, temperature, fuel-to-air ratio, and velocity, exhibited no clear effect on mixture uniformity of systems using pressure-atomizing fuel nozzles and large-scale mixing devices. However, the performance of systems using atomizing fuel nozzles and large-scale mixing devices was found to be sensitive to operating conditions. Variations in system design variables were also evaluated and correlated. Mixing uniformity was found to improve with system length, pressure drop, and the number of fuel injection points per unit area. A premixing system capable of providing mixing uniformity to within 15 percent over a typical range of cruise operating conditions is demonstrated.

49 CFR 232.217 - Train brake tests conducted using yard air.

Code of Federal Regulations, 2010 CFR

2010-10-01

... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... potential overcharge conditions to the train brake system are avoided, the yard air test device may be... section, when yard air is used the train air brake system must be charged and tested as prescribed by...

Optimization Parameters of Air-conditioning and Heat Insulation Systems of a Pressurized Cabins of Long-distance Airplanes

NASA Astrophysics Data System (ADS)

Gusev, Sergey A.; Nikolaev, Vladimir N.

2018-01-01

The method for determination of an aircraft compartment thermal condition, based on a mathematical model of a compartment thermal condition was developed. Development of solution techniques for solving heat exchange direct and inverse problems and for determining confidence intervals of parametric identification estimations was carried out. The required performance of air-conditioning, ventilation systems and heat insulation depth of crew and passenger cabins were received.

77 FR 38857 - Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Normal...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-29

... Treatment, Heating Ventilation and Air Conditioning Systems.'' This new standard provides comprehensive test... Criteria for Air Filtration and Adsorption Units of Normal Atmosphere Cleanup Systems in Light-Water-Cooled... NUCLEAR REGULATORY COMMISSION [NRC-2012-0152] Design, Inspection, and Testing Criteria for Air...

[Hygienic Inspections of Ventilation Systems Under Resting Conditions (According to DIN 1946-4:1999-03) - A Retrospective Assessment].

PubMed

Friedrich, Lena; Boeckelmann, Irina

2018-01-11

Hygienic and microbiologically sterile air quality is essential for successful guideline-based work in operating theatres. To ensure clean air and to reduce contamination during surgery, ventilation systems are indispensable. Ventilation systems should be especially designed to keep the number of particles and germs under statutory limits. Therefore, they must be operated to recognised standards of good practice and be periodically inspected and maintained. The objective of this study was to prove, through the analysis of observation outside surgery time (rest condition), the effects of ventilation systems on air quality in a medical facility. Measurements were taken in 34 operating theatres annually over a period of ten years outside surgery time (resting condition) but with the air ventilation system operating under full load. 29 operating theatres were provided with laminar air flow and five theatres with turbulent air flow systems. In each operating theatre, air cleanliness was analysed by measuring the amount of airborne particles and airborne germs. Measuring points were determined 10 mm beneath the supply-air ceiling in the centre of the operating theatre and at one position outside the supply-air ceiling. The number of airborne particles at the supply-air ceiling was between 0/m³ and 4,441/m³ of air and, as such, the limiting factor was never exceeded. However, airborne germ measurements of between 0 CFU/m³ and 200 CFU/m³ (CFU: colony forming units) demonstrated that the limiting factor for this criterion was exceeded in 10.9% of occasions. In general, the values in the middle of the room were higher than at the supply-air ceiling. There were significant differences (p < 0.001) between the values at the supply-air ceiling, the surgery table and the values outside the supply-air ceiling. The results show the positive impact of ventilation systems on the air cleanliness in operating theatres. However, laminar airflow systems seem to create cleaner air than conventional ventilation systems. The size of the supply-air ceiling plays an important role in the prevention of the contamination of the staff, the surgical field, the instrument table and the patient. However, the effect on surgical site infections has not been verified. Improved measuring methods should be considered. Georg Thieme Verlag KG Stuttgart · New York.

Control Technologies for Room Air-conditioner and Packaged Air-conditioner

NASA Astrophysics Data System (ADS)

Ito, Nobuhisa

Trends of control technologies about air-conditioning machineries, especially room or packaged air conditioners, are presented in this paper. Multiple air conditioning systems for office buildings are mainly described as one application of the refrigeration cycle control technologies including sensors for thermal comfort and heating/ cooling loads are also described as one of the system control technologies. Inverter systems and related technologies for driving variable speed compressors are described in both case of including induction motors and brushless DC motors. Technologies for more accurate control to meet various kind of regulations such as ozone layer destruction, energy saving and global warming, and for eliminating harmonic distortion of power source current, as a typical EMC problem, will be urgently desired.

Impact of surface disinfection and sterile draping of furniture on room air quality in a cardiac procedure room with a ventilation and air-conditioning system (extrusion airflow, cleanroom class 1b (DIN 1946-4)).

PubMed

Below, Harald; Ryll, Sylvia; Empen, Klaus; Dornquast, Tina; Felix, Stefan; Rosenau, Heike; Kramer, Sebastian; Kramer, Axel

2010-09-21

In a cardiac procedure room, ventilated by a ventilation and air-conditioning system with turbulent mixed airflow, a protection zone in the operating area could be defined through visualization of airflows. Within this protection zone, no turbulence was detectable in the room air.Under the given conditions, disinfection of all surfaces including all furniture and equipment after the last operation and subsequent draping of furniture and all equipment that could not be removed from the room with sterile surgical drapes improved the indoor room air quality from cleanroom class C to cleanroom class B. This also allows procedures with elevated requirements to be performed in room class 1b.

Environmental Control System Installer/Servicer (Residential Air Conditioning Mechanic). V-TECS Guide.

ERIC Educational Resources Information Center

Meyer, Calvin F.; Benson, Robert T.

This guide provides job relevant tasks, performance objectives, performance guides, resources, learning activitites, evaluation standards, and achievement testing in the occupation of environmental control system installer/servicer (residential air conditioning mechanic). It is designed to be used with any chosen teaching method. The course…

77 FR 237 - Protection of Stratospheric Ozone: Adjustments to the Allowance System for Controlling HCFC...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-04

..., Heating, and Air-Conditioning Contractors (NAICS code 238220), including Central air-conditioning system and commercial refrigeration installation; HVAC contractors. This list is not intended to be... selecting its highest ODP- weighted consumption year from among the years 1994 through 1997. [[Page 241...

AIR CLEANING FOR ACCEPTABLE INDOOR AIR QUALITY

EPA Science Inventory

The paper discusses air cleaning for acceptable indoor air quality. ir cleaning has performed an important role in heating, ventilation, and air-conditioning systems for many years. raditionally, general ventilation air-filtration equipment has been used to protect cooling coils ...

Design of a solar energy assisted air conditioning system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varlet, J.L.P.; Johnson, B.R.; Vora, J.N.

1976-03-24

Energy consumption in air conditioning systems can be reduced by reducing the water content of air before cooling. This reduction in humidity can be accomplished by contacting the humid air with a hygroscopic solution in a spray tower. The hydroscopic solution, diluted by water from the air, can be reconcentrated in a solar evaporator. A solar evaporator for this purpose was evaluated by formulating simultaneous energy and mass balances for forced air convection through the evaporator. Temperatures in the evaporator were calculated by numerical integration of the mathematical model. The calculations indicated that the salt solution cannot be reconcentrated inmore » a forced convection evaporator because of the large energy losses associated with the air stream passing through the evaporator.« less

Simulation of a solar-assisted absorption air conditioning system for applications in Puerto Rico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khan, A.Y.; Hernandez, H.R.; Gonzalez, J.E.

1995-11-01

Regions without conventional fuel sources have felt the need for the development of new technologies for air conditioning applications as cost of electrical energy production has continually risen the cost of air conditioning by conventional means. This paper deals with the simulation of a solar-assisted absorption system for air conditioning application in Puerto Rico. A simple thermodynamic model for the solar assisted absorption system has been developed. A solar energy based thermal storage system along with an auxiliary heater is used to provide the required energy in the generator of this absorption system. Results from a parametric analysis to studymore » the influence of the absorber, generator, condenser and evaporator temperatures, on the COP of the system are presented in this paper. The influence of two different refrigerant/absorbent pairs, water/lithium bromide and water/lithium-chloride have also been studied. A sub-system consisting of an array of flat plate solar collectors along with a hot water storage is modeled and verified with the data from an already existing system operating in Sacramento. Finally, off-design performance of a 35 kW solar-assisted absorption system is simulated to report the auxiliary heating requirement for a typical summer day operation in southern Puerto Rico.« less

78 FR 63183 - Information Collection Request Submitted to OMB for Review and Approval; Comment Request; Mobile...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-23

... of air conditioning systems and recovery/recycling equipment. Form Numbers: None. Respondents... automotive repair shops, automotive repair shops not elsewhere classified, including air conditioning and... Request Submitted to OMB for Review and Approval; Comment Request; Mobile Air Conditioner Retrofitting...

Development of a Dosimeter System for Unsymmetrical Dimethylhydrazine, Monomethylhydrazine and Hydrazine

DTIC Science & Technology

1994-06-27

the amount of dilution air . Conditioned house- compressed air was used as the diluent. The conditioning procedure consisted of passing the house air ...unsymmetrical dlmethylhydrazine (UDMI-) in air has been developed. The dosimeter consists of a replaceable dosimeter card and a reusable...Department of Defense and NASA require air monitoring for hydrazines in areas where they are handled and/or stored. A real-time dosimeter using vanillin

Responses of the circadian system of rats to conditioned and unconditioned stimuli.

PubMed

de Groot, M H; Rusak, B

2000-08-01

The circadian systems of rodents respond to light pulses presented during the subjective night with phase shifts and altered cellular activity in the suprachiasmatic nuclei (SCN), including expression of immediate-early genes (IEGs) such as c-fos. A recent study showed that a nonphotic stimulus (an air disturbance generated by a fan) that does not normally induce the expression of c-fos-like immunoreactivity in the SCN of rats can be made to do so after being paired repeatedly with a light pulse in a Pavlovian conditioning paradigm. Furthermore, after conditioning (but not after noncontingent exposure to these stimuli), the fan also induced phase shifts in activity and body temperature rhythms comparable to those produced by light. The authors performed three experiments designed to replicate and extend these findings in rats. In experiment 1, rats were tested for conditioning effects of repeated pairings of a light pulse with a neutral air disturbance under a full photoperiod. In experiment 2, a modified conditioning paradigm was used in which a skeleton photoperiod served as both the entraining zeitgeber and the unconditioned stimulus. Animals in the paired and unpaired training conditions were exposed to both the light pulse and the air disturbance, but the air disturbance signaled the onset of light in the paired condition only. Phase shifts of wheel-running activity rhythms and gene expression in the SCN, intergeniculate leaflet, and paraventricular nucleus of the thalamus were assessed in animals following either of the training conditions or the control procedures. Experiment 3 assessed whether the air disturbance could entrain the circadian activity rhythms of rats with or without previous pairing with light in a classical conditioning paradigm. No evidence for classical conditioning, nor for unconditioned effects of the air disturbance on the circadian system, was found in these studies.

Modification split type air conditioning unit by installing internal heat exchanger and condenser precooling

NASA Astrophysics Data System (ADS)

Ambarita, H.

2018-03-01

In this paper, a modified of air conditioning (AC) system is proposed. In the modified system, an internal heat exchanger and condenser precooling unit are installed. The objective is to explore the effect of the additional equipment to the performance of the system. An AC with compressor power of 1 PK is modified and compared with the original one. The results show that ER of the modified system is higher than the original one in order of 3.6%. The work of the compressor of the modified system is 12.5% lower than work of the compressor without modification. Finally, the COP of the modified system is 11.71% higher than the original one. These facts reveal that the combination of IHX and condenser precooling shows positive impact on the performance of the AC. It is recommended to use the modified system to improve the energy efficiency of the Air Conditioning system.

HVAC SYSTEMS AS A TOOL IN CONTROLLING INDOOR AIR QUALITY: A LITERATURE REVIEW

EPA Science Inventory

The report gives results of a review of literature on the use of heating, ventilating, and air-conditioning (HVAC) systems to control indoor air quality (IAQ). Although significant progress has been made in reducing the energy consumption of HVAC systems, their effect on indoor a...

The Design of Large Geothermally Powered Air-Conditioning Systems Using an Optimal Control Approach

NASA Astrophysics Data System (ADS)

Horowitz, F. G.; O'Bryan, L.

2010-12-01

The direct use of geothermal energy from Hot Sedimentary Aquifer (HSA) systems for large scale air-conditioning projects involves many tradeoffs. Aspects contributing towards making design decisions for such systems include: the inadequately known permeability and thermal distributions underground; the combinatorial complexity of selecting pumping and chiller systems to match the underground conditions to the air-conditioning requirements; the future price variations of the electricity market; any uncertainties in future Carbon pricing; and the applicable discount rate for evaluating the financial worth of the project. Expanding upon the previous work of Horowitz and Hornby (2007), we take an optimal control approach to the design of such systems. By building a model of the HSA system, the drilling process, the pumping process, and the chilling operations, along with a specified objective function, we can write a Hamiltonian for the system. Using the standard techniques of optimal control, we use gradients of the Hamiltonian to find the optimal design for any given set of permeabilities, thermal distributions, and the other engineering and financial parameters. By using this approach, optimal system designs could potentially evolve in response to the actual conditions encountered during drilling. Because the granularity of some current models is so coarse, we will be able to compare our optimal control approach to an exhaustive search of parameter space. We will present examples from the conditions appropriate for the Perth Basin of Western Australia, where the WA Geothermal Centre of Excellence is involved with two large air-conditioning projects using geothermal water from deep aquifers at 75 to 95 degrees C.

40 CFR Appendix B to Subpart G of... - Substitutes Subject to Use Restrictions and Unacceptable Substitutes

Code of Federal Regulations, 2011 CFR

2011-07-01

... unique fittings —must be used with detailed labels —all CFC-12 must be removed from the system prior to... potential failure of both air conditioning systems and recovery/recycling equipment. For the purposes of... use a new refrigerant includes all procedures that result in the air conditioning system using a new...

78 FR 48864 - Limited Public Interest Waiver Under the American Recovery and Reinvestment Act of 2009 (Recovery...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-12

... the installation of a heating, ventilation, and air conditioning (HVAC) system at the City of La Ca... EE0000905, for the installation of a heating, ventilation, and air conditioning (HVAC) system at the at the... efforts and MEP's scouting process, it was determined that if the described HVAC system was manufactured...

[Degradation of 2, 4-dichlorophenol in aqueous solution by ZVI/EDDS/air system].

PubMed

Sun, Qian; Zhou, Hai-Yan; Cao, Meng-Hua; Wu, Lin-Na; Wang, Lin-Ling; Chen, Jing; Lu, Xiao-Hua

2012-11-01

A new oxidation system of Fenton-like system (ZVI/EDDS/Air) has been developed to degrade 2,4-chlorophenols (2,4-DCP) in aqueous solution. The influences of initial conditions, i. e., EDDS concentration, iron dosage, aeration rate, 2,4-DCP concentration and pH as well as reaction temperature on the degradation of 2,4-DCP were studied. The results demonstrated that this ZVI/EDDS/Air system was able to effectively degrade 2,4-DCP in aqueous solution, and the degradation of 2,4-DCP conforms to the pseudo-first-order reaction kinetics equation. Removal of above 99% 2,4-DCP was achieved in ZVI/EDDS/Air system at room temperature and pressure after 1 h reaction when the initial conditions were 2,4-DCP 100 mg x L(-1), EDDS 0.80 mmo x L(-1), ZVI 20 g x L(-1), aeration rate 2 L x (min x L)(-1). Compared with ZVI/EDTA/Air system, ZVI/EDDS/Air system showed higher efficiency in the degradation of 2,4-DCP at ambient circumstance and was more environmentally benign.

[Air quality control systems: heating, ventilating, and air conditioning (HVAC)].

PubMed

Bellucci Sessa, R; Riccio, G

2004-01-01

After a brief illustration of the principal layout schemes of Heating, Ventilating, and Air Conditioning (HVAC), the first part of this paper summarizes the standards, both voluntary and compulsory, regulating HVAC facilities design and installation with regard to the question of Indoor Air Quality (IAQ). The paper then examines the problem of ventilation systems maintenance and the essential hygienistic requirements in whose absence HVAC facilities may become a risk factor for people working or living in the building. Lastly, the paper deals with HVAC design strategies and methods, which aim not only to satisfy comfort and air quality requirements, but also to ensure easy and effective maintenance procedures.

Legionella species colonization of water distribution systems, pools and air conditioning systems in cruise ships and ferries

PubMed Central

Goutziana, Georgia; Mouchtouri, Varvara A; Karanika, Maria; Kavagias, Antonios; Stathakis, Nikolaos E; Gourgoulianis, Kostantinos; Kremastinou, Jenny; Hadjichristodoulou, Christos

2008-01-01

Background Legionnaires' disease continues to be a public health concern in passenger ships. This study was scheduled in order to investigate Legionella spp. colonization of water distribution systems (WDS), recreational pools, and air-conditioning systems on board ferries and cruise ships in an attempt to identify risk factors for Legionella spp. colonization associated with ship water systems and water characteristics. Methods Water systems of 21 ferries and 10 cruise ships including WDS, air conditioning systems and pools were investigated for the presence of Legionella spp. Results The 133 samples collected from the 10 cruise ships WDS, air conditioning systems and pools were negative for Legionella spp. Of the 21 ferries WDS examined, 14 (66.7%) were legionellae-positive. A total of 276 samples were collected from WDS and air conditioning systems. Legionella spp. was isolated from 37.8% of the hot water samples and 17.5% of the cold water samples. Of the total 96 positive isolates, 87 (90.6%) were L. pneumophila. Legionella spp. colonization was positively associated with ship age. The temperature of the hot water samples was negatively associated with colonization of L. pneumophila serogroup (sg) 1 and that of L. pneumophila sg 2 to 14. Increases in pH ≥7.8 and total plate count ≥400 CFU/L, correlated positively with the counts of L. pneumophila sg 2 to 14 and Legionella spp. respectively. Free chlorine of ≥0.2 mg/L inhibited colonization of Legionella spp. Conclusion WDS of ferries can be heavily colonized by Legionella spp. and may present a risk of Legionnaires' disease for passengers and crew members. Guidelines and advising of Legionnaires' disease prevention regarding ferries are needed, in particular for operators and crew members. PMID:19025638

Legionella species colonization of water distribution systems, pools and air conditioning systems in cruise ships and ferries.

PubMed

Goutziana, Georgia; Mouchtouri, Varvara A; Karanika, Maria; Kavagias, Antonios; Stathakis, Nikolaos E; Gourgoulianis, Kostantinos; Kremastinou, Jenny; Hadjichristodoulou, Christos

2008-11-24

Legionnaires' disease continues to be a public health concern in passenger ships. This study was scheduled in order to investigate Legionella spp. colonization of water distribution systems (WDS), recreational pools, and air-conditioning systems on board ferries and cruise ships in an attempt to identify risk factors for Legionella spp. colonization associated with ship water systems and water characteristics. Water systems of 21 ferries and 10 cruise ships including WDS, air conditioning systems and pools were investigated for the presence of Legionella spp. The 133 samples collected from the 10 cruise ships WDS, air conditioning systems and pools were negative for Legionella spp. Of the 21 ferries WDS examined, 14 (66.7%) were legionellae-positive. A total of 276 samples were collected from WDS and air conditioning systems. Legionella spp. was isolated from 37.8% of the hot water samples and 17.5% of the cold water samples. Of the total 96 positive isolates, 87 (90.6%) were L. pneumophila. Legionella spp. colonization was positively associated with ship age. The temperature of the hot water samples was negatively associated with colonization of L. pneumophila serogroup (sg) 1 and that of L. pneumophila sg 2 to 14. Increases in pH >/=7.8 and total plate count > or =400 CFU/L, correlated positively with the counts of L. pneumophila sg 2 to 14 and Legionella spp. respectively. Free chlorine of > or =0.2 mg/L inhibited colonization of Legionella spp. WDS of ferries can be heavily colonized by Legionella spp. and may present a risk of Legionnaires' disease for passengers and crew members. Guidelines and advising of Legionnaires' disease prevention regarding ferries are needed, in particular for operators and crew members.

75 FR 70106 - Airworthiness Directives; Viking Air Limited (Type Certificate Previously Held by Bombardier, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-17

... states: Viking Air Limited has completed a system safety review of the aircraft fuel system against fuel... safety review of the aircraft fuel system against fuel tank safety standards introduced in Chapter 525 of... describes the unsafe condition as: Viking Air Limited has completed a system safety review of the aircraft...

A Context-Aware Indoor Air Quality System for Sudden Infant Death Syndrome Prevention

PubMed Central

De Paz, Juan F.; Barriuso, Alberto L.

2018-01-01

Context-aware monitoring systems designed for e-Health solutions and ambient assisted living (AAL) play an important role in today’s personalized health-care services. The majority of these systems are intended for the monitoring of patients’ vital signs by means of bio-sensors. At present, there are very few systems that monitor environmental conditions and air quality in the homes of users. A home’s environmental conditions can have a significant influence on the state of the health of its residents. Monitoring the environment is the key to preventing possible diseases caused by conditions that do not favor health. This paper presents a context-aware system that monitors air quality to prevent a specific health problem at home. The aim of this system is to reduce the incidence of the Sudden Infant Death Syndrome, which is triggered mainly by environmental factors. In the conducted case study, the system monitored the state of the neonate and the quality of air while it was asleep. The designed proposal is characterized by its low cost and non-intrusive nature. The results are promising. PMID:29498653

A Context-Aware Indoor Air Quality System for Sudden Infant Death Syndrome Prevention.

PubMed

De La Iglesia, Daniel H; De Paz, Juan F; Villarrubia González, Gabriel; Barriuso, Alberto L; Bajo, Javier

2018-03-02

Context-aware monitoring systems designed for e-Health solutions and ambient assisted living (AAL) play an important role in today's personalized health-care services. The majority of these systems are intended for the monitoring of patients' vital signs by means of bio-sensors. At present, there are very few systems that monitor environmental conditions and air quality in the homes of users. A home's environmental conditions can have a significant influence on the state of the health of its residents. Monitoring the environment is the key to preventing possible diseases caused by conditions that do not favor health. This paper presents a context-aware system that monitors air quality to prevent a specific health problem at home. The aim of this system is to reduce the incidence of the Sudden Infant Death Syndrome, which is triggered mainly by environmental factors. In the conducted case study, the system monitored the state of the neonate and the quality of air while it was asleep. The designed proposal is characterized by its low cost and non-intrusive nature. The results are promising.

Visualization of the influence of the air conditioning system to the high-power laser beam quality with the modulation coherent imaging method.

PubMed

Tao, Hua; Veetil, Suhas P; Pan, Xingchen; Liu, Cheng; Zhu, Jianqiang

2015-08-01

Air conditioning systems can lead to dynamic phase change in the laser beams of high-power laser facilities for the inertial confinement fusion, and this kind of phase change cannot be measured by most of the commonly employed Hartmann wavefront sensor or interferometry due to some uncontrollable factors, such as too large laser beam diameters and the limited space of the facility. It is demonstrated that this problem can be solved using a scheme based on modulation coherent imaging, and thus the influence of the air conditioning system on the performance of the high-power facility can be evaluated directly.

Uncertainty Evaluation of Residential Central Air-conditioning Test System

NASA Astrophysics Data System (ADS)

Li, Haoxue

2018-04-01

According to national standards, property tests of air-conditioning are required. However, test results could be influenced by the precision of apparatus or measure errors. Therefore, uncertainty evaluation of property tests should be conducted. In this paper, the uncertainties are calculated on the property tests of Xinfei13.6 kW residential central air-conditioning. The evaluation result shows that the property tests are credible.

[Hygienic evaluation of direct heating of the air delivered to the shaft].

PubMed

Velichkovskiĭ, B T; Malikov, Iu K; Troitskaia, N A; Belen'kaia, M A; Sergeeva, N V; Shirokova, O V; Kashanskiĭ, S V; Slyshkina, T V; Simonova, O V; Zykova, V A

2011-01-01

The paper gives the results of exploring a test pre-heating system for the air (APHS) delivered to the shaft. The system has been first used in the Urals. The supply air is heated by burning natural gas in the air current. The APHS system with a RG air heater (000 "Gas-Engineering") is equipped in addition to the existing heaters to enhance heat supply reliability in northern conditions. The data of the studies show that in all periods of the heating season (interseason, moderate frosts, the coldest month), the concentrations of hazardous substances, such as nitric oxides, nitric dioxide, sulfur dioxide, carbon dioxide, benz(a)pyrene, solid aerosol in the shaft-delivered air, do not exceed those given in the existing regulation provided that the design operating conditions are met. With the maximum gas consumption, the coldest month only was marked by the nitric dioxide content being greater than the standard values, causing the maximum projected natural gas consumption to be lower in the APHS system. The air level of nitric dioxide proved to be a major hygiene indicator while using this air heater.

An Investigation of Energy Consumption and Cost in Large Air-Conditioned Buildings. An Interim Report.

ERIC Educational Resources Information Center

Milbank, N. O.

Two similarly large buildings and air conditioning systems are comparatively analyzed as to energy consumption, costs, and inefficiency during certain measured periods of time. Building design and velocity systems are compared to heating, cooling, lighting and distribution capabilities. Energy requirements for pumps, fans and lighting are found to…

Design and demonstration of a storage assisted air conditioning system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1982-04-01

One phase-change material, sodium sulfate decahydrate, has generated considerable interest for thermal storage. A form of this material containing salts to adjust the transition point to approximately 55/sup 0/F and a gelling agent to prevent segregation of the salts has been developed. This material is packaged in the form of a CHUB, (a cylinder two inches in diameter and twenty inches long) having a weight of 3.25 pounds and a thermal storage capability of 50 Btu per pound. Under this project, a storage-assisted (partial storage) air conditioning system was designed, installed, monitored and evaluated in a typical residential application. Thismore » feasibility demonstration was conducted under the direction of the Long Island Lighting Company in a single family residence in Melville, Long Island, New York. The demonstration system consisted of a CHUB thermal storage system utilized in conjunction with a one and one-half ton air conditioning unit to cool a house that would normally require a two and one half ton air conditioning unit.« less

Cooperation of Horizontal Ground Heat Exchanger with the Ventilation Unit During Summer - Case Study

NASA Astrophysics Data System (ADS)

Romańska-Zapała, Anna; Furtak, Marcin; Dechnik, Mirosław

2017-10-01

Renewable energy sources are used in the modern energy-efficient buildings to improve their energy balance. One of them is used in the mechanical ventilation system ground air heat exchanger (earth-air heat exchanger - EAHX). This solution, right after heat recovery from exhaust air (recuperation), allows the reduction in the energy needed to obtain the desired temperature of supply air. The article presents the results of "in situ" measurements of pipe ground air heat exchanger cooperating with the air handling unit, supporting cooling the building in the summer season, in Polish climatic conditions. The laboratory consists of a ventilation unit intake - exhaust with rotor for which the source of fresh air is the air intake wall and two air intakes field cooperating with the tube with ground air heat exchangers. Selection of the source of fresh air is performed using sprocket with actuators. This system is part of the ventilation system of the Malopolska Laboratory of Energy-Efficient Building (MLBE) building of Cracow University of Technology. The measuring system are, among others, the sensors of parameters of air inlets and outlets of the heat exchanger channels EAHX and weather station that senses the local weather conditions. The measurement data are recorded and archived by the integrated process control system in the building of MLBE. During the study measurements of operating parameters of the ventilation unit cooperating with the selected source of fresh air were performed. Two cases of operation of the system: using EAHX heat exchanger and without it, were analyzed. Potentially the use of ground air heat exchanger in the mechanical ventilation system can reduce the energy demand for heating or cooling rooms by the pre-adjustment of the supply air temperature. Considering the results can be concluded that the continuous use of these exchangers is not optimal. This relationship is appropriate not only on an annual basis for the transitional periods (spring and autumn), but also in individual days in the potentially most favorable periods of work exchanger (summer and winter). Inappropriate operation of the heat exchanger, will lead to a temporary increase in energy consumption for the preparation of the desired air temperature, relative to the fresh air unit which is non-pretreated. For optimal energy system operation: exchanger EAHX - air handling unit, to preserve the most favourable parameters of inlet air to handling unit, there is a need to dynamically adjust the source of fresh air, depending on changing external conditions and the required outlet temperature of central unit (temperature of air forced to the rooms).

HVAC SYSTEMS AS EMISSION SOURCES AFFECTING INDOOR AIR QUALITY: A CRITICAL REVIEW

EPA Science Inventory

The study evaluates heating, ventilating, and air-conditioning (HVAC) systems as contaminant emission sources that affect indoor air quality (IAQ). Various literature sources and methods for characterizing HVAC emission sources are reviewed. Available methods include in situ test...

Impact of surface disinfection and sterile draping of furniture on room air quality in a cardiac procedure room with a ventilation and air-conditioning system (extrusion airflow, cleanroom class 1b (DIN 1946-4))

PubMed Central

Below, Harald; Ryll, Sylvia; Empen, Klaus; Dornquast, Tina; Felix, Stefan; Rosenau, Heike; Kramer, Sebastian; Kramer, Axel

2010-01-01

In a cardiac procedure room, ventilated by a ventilation and air-conditioning system with turbulent mixed airflow, a protection zone in the operating area could be defined through visualization of airflows. Within this protection zone, no turbulence was detectable in the room air. Under the given conditions, disinfection of all surfaces including all furniture and equipment after the last operation and subsequent draping of furniture and all equipment that could not be removed from the room with sterile surgical drapes improved the indoor room air quality from cleanroom class C to cleanroom class B. This also allows procedures with elevated requirements to be performed in room class 1b. PMID:20941336

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

PubMed

Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems

PubMed Central

Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency. PMID:28594862

Energy saving effect of desiccant ventilation system using Wakkanai siliceous shale

NASA Astrophysics Data System (ADS)

Nabeshima, Yuki; Togawa, Jun-ya; Nagano, Katsunori; Kazuyo, Tsuzuki

2017-10-01

The nuclear power station accident resulting from the Great East Japan Earthquake disaster has resulted in a constrained electricity supply. However, in this Asian region there is high temperature and high humidity and consequently dehumidification process requires a huge amount of energy. This is the reason for the increasing energy consumption in the residential and commercial sectors. Accordingly, a high efficiency air-conditioning system is needed to be developed. The desiccant ventilation system is effective to reduce energy consumption for the dehumidification process. This system is capable of dehumidifying without dew condensing unlike a conventional air-conditioning system. Then we focused on Wakkanai Siliceous Shale (WSS) as a desiccant material to develop a new desiccant ventilation system. This is low priced, high performance, new type of thing. The aim of this study is to develop a desiccant ventilation unit using the WSS rotor which can be regenerated with low-temperature by numerical calculation. The results of performance prediction of the desiccant unit, indicate that it is possible to regenerate the WSS rotor at low-temperature of between 35 - 45 °C. In addition, we produced an actual measurement for the desiccant unit and air-conditioning unit. This air-conditioning system was capable to reduce roughly 40 % of input energy consumption.

[Hygienic assessment of a recirculatory combined air-conditioning extract-and-input system in office building].

PubMed

Malysheva, A G; Abramov, E G

2006-01-01

The high concentrations of lead were reveled in the air and dust of some premises and on the filters of a combined air-conditioning extract-and-input system in the high-rise office buildings located in the ecologically lead favorable environment. The dust content of lead in some premises on the first floors dust was as high as 200 mg/kg, which was more than 6 times higher than that in the soil at the highway near the office buildings. The use of new technologies and devices for cleaning and optimizing the air in the premises requires analytical studies to assess the quality of the environment, by taking into account the optimal conditions of their operation.

Experimental performance study of a proposed desiccant based air conditioning system.

PubMed

Bassuoni, M M

2014-01-01

An experimental investigation on the performance of a proposed hybrid desiccant based air conditioning system referred as HDBAC is introduced in this paper. HDBAC is mainly consisted of a liquid desiccant dehumidification unit integrated with a vapor compression system (VCS). The VCS unit has a cooling capacity of 5.27 kW and uses 134a as refrigerant. Calcium chloride (CaCl2) solution is used as the working desiccant material. HDBAC system is used to serve low sensible heat factor applications. The effect of different parameters such as, process air flow rate, desiccant solution flow rate, evaporator box and condenser box solution temperatures, strong solution concentration and regeneration temperature on the performance of the system is studied. The performance of the system is evaluated using some parameters such as: the coefficient of performance (COPa), specific moisture removal and energy saving percentage. A remarkable increase of about 54% in the coefficient of performance of the proposed system over VCS with reheat is achieved. A maximum overall energy saving of about 46% is observed which emphasizes the use of the proposed system as an energy efficient air conditioning system.

Experimental performance study of a proposed desiccant based air conditioning system

PubMed Central

Bassuoni, M.M.

2013-01-01

An experimental investigation on the performance of a proposed hybrid desiccant based air conditioning system referred as HDBAC is introduced in this paper. HDBAC is mainly consisted of a liquid desiccant dehumidification unit integrated with a vapor compression system (VCS). The VCS unit has a cooling capacity of 5.27 kW and uses 134a as refrigerant. Calcium chloride (CaCl2) solution is used as the working desiccant material. HDBAC system is used to serve low sensible heat factor applications. The effect of different parameters such as, process air flow rate, desiccant solution flow rate, evaporator box and condenser box solution temperatures, strong solution concentration and regeneration temperature on the performance of the system is studied. The performance of the system is evaluated using some parameters such as: the coefficient of performance (COPa), specific moisture removal and energy saving percentage. A remarkable increase of about 54% in the coefficient of performance of the proposed system over VCS with reheat is achieved. A maximum overall energy saving of about 46% is observed which emphasizes the use of the proposed system as an energy efficient air conditioning system. PMID:25685475

Fungal endophthalmitis caused by Paecilomyces variotii following cataract surgery: a presumed operating room air-conditioning system contamination.

PubMed

Tarkkanen, Ahti; Raivio, Virpi; Anttila, Veli-Jukka; Tommila, Petri; Ralli, Reijo; Merenmies, Lauri; Immonen, Ilkka

2004-04-01

To report a case of delayed fungal endophthalmitis by Paecilomyces variotii following uncomplicated cataract surgery. To our knowledge this is the first reported case of postoperative endophthalmitis by this species. We report the longterm clinical follow-up of an 83-year-old female who underwent uncomplicated sutureless, small-incision cataract surgery. She developed recurring uveitis 4 months after surgery. Vitreous tap and finally complete vitrectomy with removal of the capsular bag including the intraocular lens were performed. Fungi were studied by histopathology and culture. At histopathological examination, the fungi were found to be closely related with the capsular bag. A few mononuclear inflammatory cells were encountered. At culture, Paecilomyces variotii, a common ubiquitous non-pathogenic saprophyte, was identified. Despite systemic, intravitreal and topical antifungal therapy after vitrectomy the uveitis recurred several times, but no fungal organisms were isolated from the repeat intraocular specimen. At 18 months postoperatively the subject's visual acuity was finger counting at 2 metres. At the time of surgery the operating room air-conditioning system was undergoing repairs. Cases of fungal endophthalmitis after contamination from air-conditioning ventilation systems have been reported before, but none of the cases reported have been caused by P. variotii. P. variotii, a non-pathogenic environmental saprophyte, may be disastrous if introduced into the eye. International recommendations on the environmental control of the operating room air-conditioning ventilation system should be strictly followed. No intraoperative surgery should be undertaken while the air-conditioning system is undergoing repairs or service.

Selecting HVAC Systems for Schools To Balance the Needs for Indoor Air Quality, Energy Conservation and Maintenance. Technical Bulletin.

ERIC Educational Resources Information Center

Wheeler, Arthur E.; Kunz, Walter S., Jr.

Although poor air quality in a school can have multiple causes, the heating, ventilating, and air-conditioning (HVAC) system plays a major role. Suggestions that architects, facilities managers, school board members, and administrators can use in selecting HVAC systems are discussed. Focus is on the performance criteria for classroom systems, and…

40 CFR 86.167-17 - AC17 Air Conditioning Emissions Test Procedure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... tolerances (such as may occur during gear changes) are acceptable provided they occur for less than 2 seconds... setting changed to “outside air.” (l) Test procedure. The AC17 air conditioning test is composed of the..., interior volume, climate control system type and characteristics, refrigerant used, compressor type, and...

Air Conditioning, Heating, and Ventilating: Construction, Supervision, and Inspection. Course of Study.

ERIC Educational Resources Information Center

Messer, John D.

This course of study on air conditioning, heating, and ventilating is part of a construction, supervision, and inspection series, which provides instructional materials for community or junior college technical courses in the inspection program. Material covered pertains to: piping and piping systems; air movers; boilers; heat exchangers; cooling…

14 CFR 1310.15 - Amendment or Waiver of a term or condition of a guaranteed loan.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Amendment or Waiver of a term or condition of a guaranteed loan. 1310.15 Section 1310.15 Aeronautics and Space AIR TRANSPORTATION SYSTEM STABILIZATION AIR TRANSPORTATION STABILIZATION BOARD AIR CARRIER GUARANTEE LOAN PROGRAM ADMINISTRATIVE...

Vein-style air pumping tube and tire system and method of assembly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benedict, Robert Leon; Gobinath, Thulasiram; Lin, Cheng-Hsiung

An air pumping tube and tire system and method of assembling is provided in which a tire groove is formed to extend into a flexing region of a tire sidewall and a complementary air pumping tube inserts into the tire groove. In the green, uncured air pumping tube condition, one or more check valves are assembled into the air pumping tube through access shafts and align with an internal air passageway of the air pumping tube. Plug components of the system enclose the check valves in the air pumping tube and the check valve-containing green air pumping tube is thenmore » cured.« less

24 CFR 3280.709 - Installation of appliances.

Code of Federal Regulations, 2011 CFR

2011-04-01

... systems designed only to accept external cooling (i.e., self contained air conditioning systems, etc.) (7) The installation of a self contained air conditioner comfort cooling appliance shall meet the... fireplace or fireplace stove, air intake assembly, hearth extension and the chimney shall be installed in...

HVAC SYSTEMS AS EMISSION SOURCES AFFECTING INDOOR AIR QUALITY: A CRITICAL REVIEW

EPA Science Inventory

The paper discusses results of an evaluation of literature on heating, ventilating, and air-conditioning (HVAC) systems as contaminant emission sources that affect indoor air quality (IAQ). The various literature sources and methods for characterizing HVAC emission sources are re...

Thermal storage HVAC system retrofit provides economical air conditioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, S.F.

1993-03-01

This article describes an EMS-controlled HVAC system that meets the ventilation and cooling needs of an 18,000-seat indoor ice hockey arena. The Buffalo Memorial Auditorium (affectionately referred to as the Aud) was built in 1937 under the Works Project Administration of the federal government. Its original configuration included a 12,000-seat arena with an ice skating rink. By the late 1980s, the city was unsuccessfully attempting to attract events and tenants to the auditorium, which lacked air conditioning and other modern amenities. Thus, it was decided to renovate the facility to make it marketable. The first phase of the renovation includedmore » installing an air-conditioning system in the arena and repairing the existing building systems that were inoperable because of deferred maintenance. After considering the existing conditions (such as size of the space, intermittent usage, construction restrictions, operating budgets and the limited operations staff), the engineering team designed an innovative HVAC system. The system's features include: a carbon dioxide monitoring device that controls the intake of outside air; an ice storage system that provides chilled water and shifts electrical demand to off-peak hours; and a design that uses the building mass as a heat sink. A new energy management system (EMS) determines building cooling needs based on the type of event, ambient conditions and projected audience size. Then, it selects the most economical method to obtain the desired arena temperature.« less

Effect of central ventilation and air conditioner system on the concentration and health risk from airborne polycyclic aromatic hydrocarbons.

PubMed

Lv, Jinze; Zhu, Lizhong

2013-03-01

Central ventilation and air conditioner systems are widely utilized nowadays in public places for air exchange and temperature control, which significantly influences the transfer of pollutants between indoors and outdoors. To study the effect of central ventilation and air conditioner systems on the concentration and health risk from airborne pollutants, a spatial and temporal survey was carried out using polycyclic aromatic hydrocarbons (PAHs) as agent pollutants. During the period when the central ventilation system operated without air conditioning (AC-off period), concentrations of 2-4 ring PAHs in the model supermarket were dominated by outdoor levels, due to the good linearity between indoor air and outdoor air (r(p) > 0.769, p < 0.05), and the slopes (1.2-4.54) indicated that ventilating like the model supermarket increased the potential health risks from low molecular weight PAHs. During the period when the central ventilation and air conditioner systems were working simultaneously (AC-on period), although the total levels of PAHs were increased, the concentrations and percentage of the particulate PAHs indoors declined significantly. The BaP equivalency (BaPeq) concentration indicated that utilization of air conditioning reduced the health risks from PAHs in the model supermarket.

Geothermal as a heat sink application for raising air conditioning efficency

NASA Astrophysics Data System (ADS)

Ibrahim, Hesham Safwat Osman Mohamed

2016-04-01

Objective: Geothermal applications in heating, ventilation, air-conditioning is a US technology for more than 30 years old ,which saves more than 30% average energy cost than the traditional air-conditioning systems systems. Applying this technology in Middle East and African countries would be very feasible specially in Egypt specially as it suffers Electric crisis --The temperature of the condensers and the heat rejecting equipment is much higher than the Egyptian land at different depth which is a great advantages, and must be measured, recorded, and studied accurately -The Far goal of the proposal is to construct from soil analysis a temperature gradient map for Egypt and , African countries on different depth till 100 m which is still unclear nowadays and must be measured and recorded in databases through researches - The main model of the research is to study the heat transfer gradient through the ground earth borehole,grout,high density polyethylene pipes , and water inlet temperature which affect the electric efficiency of the ground source heat pump air conditioning unit Impact on the Region: Such research result will contribute widely in Energy saving sector specially the air conditioning sector in Egypt and the African countries which consumes more than 30% of the electric consumption of the total consumption . and encouraging Green systems such Geothermal to be applied

Fuel consumption and CO2/pollutant emissions of mobile air conditioning at fleet level - new data and model comparison.

PubMed

Weilenmann, Martin F; Alvarez, Robert; Keller, Mario

2010-07-01

Mobile air conditioning (MAC) systems are the second-largest energy consumers in cars after driving itself. While different measurement series are available to illustrate their behavior in hot ambient conditions, little data are available for lower temperatures. There are also no data available on diesel vehicles, despite these being quite common in Europe (up to 70% of the fleet in some countries). In the present study, six representative modern diesel passenger cars were tested. In combination with data from previous measurements on gasoline cars, a new model was developed - EEMAC = Empa Emission model for Mobile Air Conditioning systems - to predict emissions from air conditioning. The measurements obtained show that A/C activity still occurs at temperatures below the desired interior temperature. The EEMAC model was applied to the average meteorological year of a central European region and compared with the US EPA MOBILE6 model. As temperatures in central Europe are often below 20 degrees C (the point below which the two models differ), the overall results differ clearly. The estimated average annual CO(2) output according to EEMAC is six times higher than that of MOBILE6. EEMAC also indicates that around two-thirds of the fuel used for air conditioning could be saved by switching the MAC system off below 18 degrees C.

Status Report on Medical Materiel Items Tested and Evaluated for Use in the USAF Aeromedical Evacuation System

DTIC Science & Technology

1990-12-01

Volumetric Infusion Pump is conditionally acceptable for use. The Air -In- Line detector does not sense air bubbles 0.95 cm (3/8 inch) or smaller...been fitted with an improved brushless air circulation motor, Brailsford model T- 2NFR. Using the new motor, the 185 passed EMI and is acceptable for...USAF School of Aerospace Medicine, Human Systems Division, Air Force Systems Command, Brooks Air Force Base, Texas, under job order 7930-16- 12. This

V-TECS Guide for Automobile Air Conditioning and Electrical System Technician.

ERIC Educational Resources Information Center

Meyer, Calvin F.; Benson, Robert T.

This curriculum guide provides an outline for an eight-unit course to train automobile air conditioning and electrical system technicians. Each unit focuses on a duty that is composed of a number of performance objectives. For each objective, these materials are provided: a task, a standard of performance of task, source of standard, conditions…

76 FR 48147 - Notice of Intent To Grant Exclusive Patent License Agreement; OxiCool, Inc.

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-08

... fields of use on commercial and residential air conditioning systems, to practice in the United States, the Government-Owned invention, as identified in U.S. Patent Number 7,836,732 b2: Air Conditioning System, issued on November 23, 2010. DATES: Anyone wishing to object to granting of this license must...

Heat Pipes

NASA Technical Reports Server (NTRS)

1991-01-01

Phoenix Refrigeration Systems, Inc.'s heat pipe addition to the Phoenix 2000, a supermarket rooftop refrigeration/air conditioning system, resulted from the company's participation in a field test of heat pipes. Originally developed by NASA to control temperatures in space electronic systems, the heat pipe is a simple, effective, heat transfer system. It has been used successfully in candy storage facilities where it has provided significant energy savings. Additional data is expected to fully quantify the impact of the heat pipes on supermarket air conditioning systems.

Residential air-conditioning and climate change: voices of the vulnerable.

PubMed

Farbotko, Carol; Waitt, Gordon

2011-12-01

Decreasing the risk of heat-stress is an imperative in health promotion, and is widely accepted as necessary for successful adaptation to climate change. Less well understood are the vulnerabilities that air-conditioning use exacerbates, and conversely, the need for the promotion of alternative strategies for coping with heat wave conditions. This paper considers these issues with a focus on the role of air-conditioning in the everyday life of elderly public housing tenants living alone, a sector of the population that has been identified as being at high risk of suffering heat stress. A vulnerability analysis of domestic air-conditioning use, drawing on literature and policy on air-conditioning practices and ethnographic research with households. Residential air-conditioning exacerbated existing inequities. Case studies of two specifically selected low-income elderly single person households revealed that such households were unlikely to be able to afford this 'solution' to increasing exposure to heat waves in the absence of energy subsidies. Residential air-conditioning use during heat waves caused unintended side-effects, such as system-wide blackouts, which, in turn, led to escalating electricity costs as power companies responded by upgrading infrastructure to cope with periods of excess demand. Air-conditioning also contributed to emissions that cause climate change. Residential air-conditioning is a potentially maladaptive technology for reducing the risk of heat stress.

Transitioning to Low-GWP Alternatives in Residential and Commercial Air Conditioning

EPA Pesticide Factsheets

This fact sheet provides information on low-GWP alternatives in newly manufactured residential and commercial air conditioning systems. It discusses HFC alternatives, market trends, challenges to market entry for alternatives, and potential solutions.

Air Conditioning Modifications to AMG Buses

DOT National Transportation Integrated Search

1983-12-01

This report presents the documentation and evaluation of air conditioning system modifications devised by Miami (Florida) Metrobus and Los Angeles SCRTD for the AM General Model B bus. The objective of these modifications was to reduce the frequency ...

Potential emission savings from refrigeration and air conditioning systems by using low GWP refrigerants

DOE PAGES

Beshr, Mohamed; Aute, Vikrant; Abdelaziz, Omar; ...

2016-08-24

Refrigeration and air conditioning systems have high, negative environmental impacts due to refrigerant charge leaks from the system and their corresponding high global warming potential. Thus, many efforts are in progress to obtain suitable low GWP alternative refrigerants and more environmentally friendly systems for the future. In addition, the system’s life cycle climate performance (LCCP) is a widespread metric proposed for the evaluation of the system’s environmental impact.

Potential emission savings from refrigeration and air conditioning systems by using low GWP refrigerants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beshr, Mohamed; Aute, Vikrant; Abdelaziz, Omar

Refrigeration and air conditioning systems have high, negative environmental impacts due to refrigerant charge leaks from the system and their corresponding high global warming potential. Thus, many efforts are in progress to obtain suitable low GWP alternative refrigerants and more environmentally friendly systems for the future. In addition, the system’s life cycle climate performance (LCCP) is a widespread metric proposed for the evaluation of the system’s environmental impact.

40 CFR 89.326 - Engine intake air humidity measurement.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine intake air humidity measurement... Test Equipment Provisions § 89.326 Engine intake air humidity measurement. (a) Humidity conditioned air... type of intake air supply, the humidity measurements must be made within the intake air supply system...

Risk factors in heating, ventilating, and air-conditioning systems for occupant symptoms in US office buildings: the US EPA BASE study.

PubMed

Mendell, M J; Lei-Gomez, Q; Mirer, A G; Seppänen, O; Brunner, G

2008-08-01

Building-related symptoms in office workers worldwide are common, but of uncertain etiology. One cause may be contaminants related to characteristics of heating, ventilating, and air-conditioning (HVAC) systems. We analyzed data from 97 representative air-conditioned US office buildings in the Building Assessment and Survey Evaluation (BASE) study. Using logistic regression models with generalized estimating equations, we estimated odds ratios (OR) and 95% confidence intervals for associations between building-related symptom outcomes and HVAC characteristics. Outdoor air intakes less than 60 m above ground level were associated with significant increases in most symptoms: e.g. for upper respiratory symptoms, OR for intake heights 30 to 60 m, 0 to <30 m, and below ground level were 2.7, 2.0, and 2.1. Humidification systems with poor condition/maintenance were associated with significantly increased upper respiratory symptoms, eye symptoms, fatigue/difficulty concentrating, and skin symptoms, with OR = 1.5, 1.5, 1.7, and 1.6. Less frequent cleaning of cooling coils and drain pans was associated with significantly increased eye symptoms and headache, with OR = 1.7 and 1.6. Symptoms may be due to microbial exposures from poorly maintained ventilation systems and to greater levels of vehicular pollutants at air intakes nearer the ground level. Replication and explanation of these findings is needed. These findings support current beliefs that moisture-related HVAC components such as cooling coils and humidification systems, when poorly maintained, may be sources of contaminants that cause adverse health effects in occupants, even if we cannot yet identify or measure the causal exposures. While finding substantially elevated risks for poorly maintained humidification systems, relative to no humidification systems, the findings do not identify important (symptom) benefits from well-maintained humidification systems. Findings also provide an initial suggestion, needing corroboration, that outdoor air intakes lower than 18 stories in office buildings may be associated with substantial increases in many symptoms. If this is corroborated and linked to ground-level vehicle emissions, urban ventilation air intakes may need to be located as far above ground level as possible or to incorporate air cleaners that remove gaseous pollutants.

Air ion exposure system for plants

NASA Technical Reports Server (NTRS)

Morrow, R. C.; Tibbitts, T. W.

1987-01-01

A system was developed for subjecting plants to elevated air ion levels. This system consisted of a rectangular Plexiglas chamber lined with a Faraday cage. Air ions were generated by corona discharge from frayed stainless steel fibers placed at one end of the chamber. This source was capable of producing varying levels of either positive or negative air ions. During plant exposures, environmental conditions were controlled by operating the unit in a growth chamber.

Air ion exposure system for plants.

PubMed

Morrow, R C; Tibbitts, T W

1987-02-01

A system was developed for subjecting plants to elevated air ion levels. This system consisted of a rectangular Plexiglas chamber lined with a Faraday cage. Air ions were generated by corona discharge from frayed stainless steel fibers placed at one end of the chamber. This source was capable of producing varying levels of either positive or negative air ions. During plant exposures, environmental conditions were controlled by operating the unit in a growth chamber.

High Technology Centrifugal Compressor for Commercial Air Conditioning Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruckes, John

2006-04-15

R&D Dynamics, Bloomfield, CT in partnership with the State of Connecticut has been developing a high technology, oil-free, energy-efficient centrifugal compressor called CENVA for commercial air conditioning systems under a program funded by the US Department of Energy. The CENVA compressor applies the foil bearing technology used in all modern aircraft, civil and military, air conditioning systems. The CENVA compressor will enhance the efficiency of water and air cooled chillers, packaged roof top units, and other air conditioning systems by providing an 18% reduction in energy consumption in the unit capacity range of 25 to 350 tons of refrigeration Themore » technical approach for CENVA involved the design and development of a high-speed, oil-free foil gas bearing-supported two-stage centrifugal compressor, CENVA encompassed the following high technologies, which are not currently utilized in commercial air conditioning systems: Foil gas bearings operating in HFC-134a; Efficient centrifugal impellers and diffusers; High speed motors and drives; and System integration of above technologies. Extensive design, development and testing efforts were carried out. Significant accomplishments achieved under this program are: (1) A total of 26 builds and over 200 tests were successfully completed with successively improved designs; (2) Use of foil gas bearings in refrigerant R134a was successfully proven; (3) A high speed, high power permanent magnet motor was developed; (4) An encoder was used for signal feedback between motor and controller. Due to temperature limitations of the encoder, the compressor could not operate at higher speed and in turn at higher pressure. In order to alleviate this problem a unique sensorless controller was developed; (5) This controller has successfully been tested as stand alone; however, it has not yet been integrated and tested as a system; (6) The compressor successfully operated at water cooled condensing temperatures Due to temperature limitations of the encoder, it could not be operated at air cooled condensing temperatures. (7) The two-stage impellers/diffusers worked well separately but combined did not match well.« less

New Whole-House Solutions Case Study: Hydronic Heating Coil Versus Propane Furnace, Rehoboth Beach, Delaware

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2014-01-01

In this project involving two homes, the IBACOS team evaluated the performance of the two space conditioning systems and the modeled efficiency of the two tankless domestic hot water systems relative to actual occupant use. Each house was built by Insight Homes and is 1,715-ft2 with a single story, three bedrooms, two bathrooms, and the heating, ventilation, and air conditioning systems and ductwork located in conditioned crawlspaces. The standard house, which the builder offers as its standard production house, uses an air source heat pump (ASHP) with supplemental propane furnace heating. The Building America test house uses the same ASHPmore » unit with supplemental heat provided by the DHW heater (a combined DHW and hydronic heating system, where the hydronic heating element is in the air handler).« less

A Study of Demand Response Effect of Thermal Storage Air-Conditioning Systems in Consideration of Electricity Market Prices

NASA Astrophysics Data System (ADS)

Omagari, Yuko; Sugihara, Hideharu; Tsuji, Kiichiro

This paper evaluates the economic impact of the introduction of customer-owned Thermal Storage Air-conditioning (TSA) systems, in an electricity market, from the viewpoint of the load service entity. We perform simulations on the condition that several thousand customers install TSA systems and shift peak demand in an electricity market by one percent. Our numerical results indicate that the purchase cost of the LSE was reduced through load management of customers with TSA systems. The introduction of TSA systems also reduced the volatility of market clearing price and reduced the whole-trade cost in an electricity market.

Air Conditioning with Magnetic Refrigeration : An Efficient, Green Compact Cooling System Using Magnetic Refrigeration

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-09-01

BEETIT Project: Astronautics is developing an air conditioning system that relies on magnetic fields. Typical air conditioners use vapor compression to cool air. Vapor compression uses a liquid refrigerant to circulate within the air conditioner, absorb the heat, and pump the heat out into the external environment. Astronautics’ design uses a novel property of certain materials, called “magnetocaloric materials”, to achieve the same result as liquid refrigerants. These magnetocaloric materials essentially heat up when placed within a magnetic field and cool down when removed, effectively pumping heat out from a cooler to warmer environment. In addition, magnetic refrigeration uses nomore » ozone-depleting gases and is safer to use than conventional air conditioners which are prone to leaks.« less

Ceiling-mounted personalized ventilation system integrated with a secondary air distribution system--a human response study in hot and humid climate.

PubMed

Yang, B; Sekhar, S C; Melikov, A K

2010-08-01

The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration of PV systems with the work station. A newly developed ceiling-mounted PV system addresses these challenges and provides a practical solution while retaining much of the apparent benefits of PV systems. Assessments of thermal environment, air movement, and air quality for ceiling-mounted PV system were performed with tropically acclimatized subjects in a Field Environmental Chamber. Thirty-two subjects performed normal office work and could choose to be exposed to four different PV airflow rates (4, 8, 12, and 16 L/s), thus offering themselves a reasonable degree of individual control. Ambient temperatures of 26 and 23.5 degrees C and PV air temperatures of 26, 23.5, and 21 degrees C were employed. The local and whole body thermal sensations were reduced when PV airflow rates were increased. Inhaled air temperature was perceived cooler and perceived air quality and air freshness improved when PV airflow rate was increased or temperature was reduced. The newly developed ceiling-mounted PV system offers a practical solution to the integration of PV air terminal devices (ATDs) in the vicinity of the workstation. By remotely locating the PV ATDs on the ceiling directly above the occupants and under their control, the conditioned outdoor air is now provided to the occupants through the downward momentum of the air. A secondary air-conditioning and air distribution system offers additional cooling in the room and maintains a higher ambient temperature, thus offering significant benefits in conserving energy. The results of this study provide designers and consultants with needed knowledge for design of PV systems.

Resources and Fact Sheets on Servicing Motor Vehicle Air Conditioners (Summary Page)

EPA Pesticide Factsheets

Page provides links to resources that can assist motor vehicle air-conditioning system technicians in understanding system servicing requirements and best practices, and learn about alternative refrigerants.

Environmental impacts and sustainability of egg production systems.

PubMed

Xin, H; Gates, R S; Green, A R; Mitloehner, F M; Moore, P A; Wathes, C M

2011-01-01

As part of a systemic assessment toward social sustainability of egg production, we have reviewed current knowledge about the environmental impacts of egg production systems and identified topics requiring further research. Currently, we know that 1) high-rise cage houses generally have poorer air quality and emit more ammonia than manure belt (MB) cage houses; 2) manure removal frequency in MB houses greatly affects ammonia emissions; 3) emissions from manure storage are largely affected by storage conditions, including ventilation rate, manure moisture content, air temperature, and stacking profile; 4) more baseline data on air emissions from high-rise and MB houses are being collected in the United States to complement earlier measurements; 5) noncage houses generally have poorer air quality (ammonia and dust levels) than cage houses; 6) noncage houses tend to be colder during cold weather due to a lower stocking density than caged houses, leading to greater feed and fuel energy use; 7) hens in noncage houses are less efficient in resource (feed, energy, and land) utilization, leading to a greater carbon footprint; 8) excessive application of hen manure to cropland can lead to nutrient runoff to water bodies; 9) hen manure on open (free) range may be subject to runoff during rainfall, although quantitative data are lacking; 10) mitigation technologies exist to reduce generation and emission of noxious gases and dust; however, work is needed to evaluate their economic feasibility and optimize design; and 11) dietary modification shows promise for mitigating emissions. Further research is needed on 1) indoor air quality, barn emissions, thermal conditions, and energy use in alternative hen housing systems (1-story floor, aviary, and enriched cage systems), along with conventional housing systems under different production conditions; 2) environmental footprint for different US egg production systems through life cycle assessment; 3) practical means to mitigate air emissions from different production systems; 4) process-based models for predicting air emissions and their fate; and 5) the interactions between air quality, housing system, worker health, and animal health and welfare.

Indoor air quality and health in two office buildings with different ventilation systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hedge, A.; Sterling, T.D.; Sterling, E.M.

1989-01-01

Measurements of indoor air pollutants were taken in (1) an air conditioned and (2) an adjacent, naturally ventilated office of a public sector organization. Self-administered questionnaires on the work environment and health were distributed to all workers. No differences in concentrations of carbon monoxide, carbon dioxide, ozone, and total oxidants were found between buildings. Concentrations of formaldehyde, volatile organic compounds, and respirable particulates were higher in the air conditioned offices. Symptoms of sleepiness, nasal irritation, concentration difficulties, cold/flu-like symptoms, and eye focusing problems were significantly more prevalent in the air conditioned offices. In the air conditioned offices, most symptoms weremore » significantly more prevalent among women than men. Passive smoking was associated with symptom prevalence, but alcohol, tea, and coffee consumption was unrelated. No significant correlations between pollutant concentrations and symptom prevalence were found, however, recalled reports of leaving work early because of feeling ill were significantly correlated with formaldehyde levels in the air conditioned building.« less

System design and analysis of the trans-critical carbon-dioxide automotive air-conditioning system.

PubMed

Mu, Jing-Yang; Chen, Jiang-Ping; Chen, Zhi-Jiu

2003-01-01

As an environmentally harmless and feasible alternate refrigerant, CO2 has attracted worldwide attention, especially in the area of automobile air-conditioning (AAC). The thermal property of CO2 and its trans-critical refrigeration cycle is very different from that of the traditional CFC or HCFC system. The detailed process of CO2 system thermal cycle design and optimization is described in this paper. System prototype and performance test bench were developed to analyze the performance of the CO2 AAC system.

PAN AIR: A computer program for predicting subsonic or supersonic linear potential flows about arbitrary configurations using a higher order panel method. Volume 2: User's manual (version 3.0)

NASA Technical Reports Server (NTRS)

Sidwell, Kenneth W.; Baruah, Pranab K.; Bussoletti, John E.; Medan, Richard T.; Conner, R. S.; Purdon, David J.

1990-01-01

A comprehensive description of user problem definition for the PAN AIR (Panel Aerodynamics) system is given. PAN AIR solves the 3-D linear integral equations of subsonic and supersonic flow. Influence coefficient methods are used which employ source and doublet panels as boundary surfaces. Both analysis and design boundary conditions can be used. This User's Manual describes the information needed to use the PAN AIR system. The structure and organization of PAN AIR are described, including the job control and module execution control languages for execution of the program system. The engineering input data are described, including the mathematical and physical modeling requirements. Version 3.0 strictly applies only to PAN AIR version 3.0. The major revisions include: (1) inputs and guidelines for the new FDP module (which calculates streamlines and offbody points); (2) nine new class 1 and class 2 boundary conditions to cover commonly used modeling practices, in particular the vorticity matching Kutta condition; (3) use of the CRAY solid state Storage Device (SSD); and (4) incorporation of errata and typo's together with additional explanation and guidelines.

The Evaluation of Unitary & Central Type Air-Conditioning Systems in Selected Florida Schools.

ERIC Educational Resources Information Center

Bradley, William B.

The study reported here was conducted in an effort to obtain data for comparing the combined owning and operating costs of two different types of air-conditioning systems in two elementary schools. Both schools were built during 1969-70 in the same geographical area along the southeast coast of Florida and are also served by the same electric…

26 CFR 6a.103A-3 - Qualified veterans' mortgage bonds.

Code of Federal Regulations, 2010 CFR

2010-04-01

... renovation of plumbing or electric systems, the installation of improved heating or air conditioning systems... the active military, naval, or air service, and who was discharged or released therefrom under...

Research on the operation control strategy of the cooling ceiling combined with fresh air system

NASA Astrophysics Data System (ADS)

Huang, Tao; Li, Hao

2018-03-01

The cooling ceiling combined with independent fresh air system was built by TRNSYS. And the cooling effects of the air conditioning system of an office in Beijing in a summer typical day were simulated. Based on the “variable temperature” control strategy, the operation strategy of “variable air volume auxiliary adjustment” was put forward. The variation of the indoor temperature, the indoor humidity, the temperature of supplying water and the temperature of returning water were simulated under the two control strategies. The energy consumption of system during the whole summer was compared by utilizing the two control strategies, and the indoor thermal comfort was analyzed. The optimal control strategy was proposed under the condition that the condensation on the surface of the cooling ceiling is not occurred and the indoor thermal comfort is satisfied.

Buildings operations and ETS exposure.

PubMed Central

Spengler, J D

1999-01-01

Mechanical systems are used in buildings to provide conditioned air, dissipate thermal loads, dilute contaminants, and maintain pressure differences. The characteristics of these systems and their operations h implications for the exposures of workers to environmental tobacco smoke (ETS) and for the control of these exposures. This review describes the general features of building ventilation systems and the efficacy of ventilation for controlling contaminant concentrations. Ventilation can reduce the concentration of ETS through dilution, but central heating, ventilating, and air conditioning (HVAC) can also move air throughout a building that has been contaminated by ETS. An understanding of HVAC systems is needed to develop models for exposures of workers to ETS. Images Figure 1 Figure 2 Figure 3 PMID:10375293

26 CFR 52.4682-4 - Floor stocks tax.

Code of Federal Regulations, 2010 CFR

2010-04-01

...-conditioning system are not used as materials in the manufacture of articles produced in the factory. (v... conditioners. Example 4. D operates an air-conditioning repair service and holds an ODC for use in repairing... sale. However, the tax is imposed on a can of ODC used to recharge an air conditioning unit because the...

Discussion on fresh air volume in Temperature and Humidity Independent Control of Air-conditioning System

NASA Astrophysics Data System (ADS)

Cheng, Xiaolong; Liu, Jinxiang; Wang, Yu; Yuan, Xiaolei; Jin, Hui

2018-05-01

The fresh air volume in Temperature and Humidity Independent Control of Air-conditioning System(THIC) of a typical office was comfirmed, under the premise of adopting the refrigeration dehumidifying fresh air unit(7°C/12°C). By detailed calculating the space moisture load and the fresh air volume required for dehumidification in 120 selected major cities in China, it can be inferred that the minimum fresh air volume required for dehumidification in THIC is mainly determined by the local outdoor air moisture and the outdoor wind speed; Then the mathematical fitting software Matlab was used to fit the three parameters, and a simplified formula for calculating the minimum per capita fresh air volume required for dehumidification was obtained; And the indoor relative humidity was simulated by the numerical software Airpak and the results by using the formula data and the data for hygiene were compared to verify the relibility of the simplified formula.

Clinical Issues-November 2017.

PubMed

Johnstone, Esther M

2017-11-01

Heating, ventilation, and air-conditioning (HVAC) systems in the OR Key words: airborne contaminants, HVAC system, air pressure, air quality, temperature and humidity. Air changes and positive pressure Key words: air changes, positive pressure airflow, unidirectional airflow, outdoor air, recirculated air. Product selection Key word: product evaluation, product selection, selection committee. Entry into practice Key words: associate degree in nursing, bachelor of science in nursing, entry-level position, advanced education, BSN-prepared RNs. Mentoring in perioperative nursing Key words: mentor, novice, practice improvement, nursing workforce. Copyright © 2017 AORN, Inc. Published by Elsevier Inc. All rights reserved.

24 CFR 902.21 - Physical condition standards for public housing-decent, safe, and sanitary housing in good repair...

Code of Federal Regulations, 2013 CFR

2013-04-01

..., electrical system, elevators, emergency power, fire protection, heating/ventilation/air conditioning (HVAC... HOUSING ASSESSMENT SYSTEM Physical Condition Indicator § 902.21 Physical condition standards for public... the major physical areas of public housing: Site, building exterior, building systems, dwelling units...

24 CFR 902.21 - Physical condition standards for public housing-decent, safe, and sanitary housing in good repair...

Code of Federal Regulations, 2014 CFR

2014-04-01

..., electrical system, elevators, emergency power, fire protection, heating/ventilation/air conditioning (HVAC... HOUSING ASSESSMENT SYSTEM Physical Condition Indicator § 902.21 Physical condition standards for public... the major physical areas of public housing: Site, building exterior, building systems, dwelling units...

24 CFR 902.21 - Physical condition standards for public housing-decent, safe, and sanitary housing in good repair...

Code of Federal Regulations, 2011 CFR

2011-04-01

..., electrical system, elevators, emergency power, fire protection, heating/ventilation/air conditioning (HVAC... HOUSING ASSESSMENT SYSTEM Physical Condition Indicator § 902.21 Physical condition standards for public... the major physical areas of public housing: Site, building exterior, building systems, dwelling units...

24 CFR 902.21 - Physical condition standards for public housing-decent, safe, and sanitary housing in good repair...

Code of Federal Regulations, 2012 CFR

2012-04-01

..., electrical system, elevators, emergency power, fire protection, heating/ventilation/air conditioning (HVAC... HOUSING ASSESSMENT SYSTEM Physical Condition Indicator § 902.21 Physical condition standards for public... the major physical areas of public housing: Site, building exterior, building systems, dwelling units...

Estimation and Control of Nonlinear and Hybrid Systems with Applications to Air-to-Air Guidance

DTIC Science & Technology

1989-03-31

systems. flexible structures [13], and last but not least Hence, some conditions for detariniing the macroeconomic models (5]. stability of hybrid...equation being defined almost everywhere, the propagation of the characteristic function is introduced. Denote the characteristic function of Pa as Oa (v,w...initial condition is ( Da (v,w;Ox,zo;O)=ejvxoejwzo and the auxilary conditions correspond to (13), i.e., 0a(O,O;TlxO,zO;O)=. Similar to the case for the

Prototype of a computer method for designing and analyzing heating, ventilating and air conditioning proportional, electronic control systems

NASA Astrophysics Data System (ADS)

Barlow, Steven J.

1986-09-01

The Air Force needs a better method of designing new and retrofit heating, ventilating and air conditioning (HVAC) control systems. Air Force engineers currently use manual design/predict/verify procedures taught at the Air Force Institute of Technology, School of Civil Engineering, HVAC Control Systems course. These existing manual procedures are iterative and time-consuming. The objectives of this research were to: (1) Locate and, if necessary, modify an existing computer-based method for designing and analyzing HVAC control systems that is compatible with the HVAC Control Systems manual procedures, or (2) Develop a new computer-based method of designing and analyzing HVAC control systems that is compatible with the existing manual procedures. Five existing computer packages were investigated in accordance with the first objective: MODSIM (for modular simulation), HVACSIM (for HVAC simulation), TRNSYS (for transient system simulation), BLAST (for building load and system thermodynamics) and Elite Building Energy Analysis Program. None were found to be compatible or adaptable to the existing manual procedures, and consequently, a prototype of a new computer method was developed in accordance with the second research objective.

Effectiveness of photocatalytic filter for removing volatile organic compounds in the heating, ventilation, and air conditioning system.

PubMed

Yu, Kuo-Pin; Lee, Grace Whei-May; Huang, Wei-Ming; Wu, Chih-Cheng; Lou, Chia-ling; Yang, Shinhao

2006-05-01

Nowadays, the heating, ventilation, and air conditioning (HVAC) system has been an important facility for maintaining indoor air quality. However, the primary function of typical HVAC systems is to control the temperature and humidity of the supply air. Most indoor air pollutants, such as volatile organic compounds (VOCs), cannot be removed by typical HVAC systems. Thus, some air handling units for removing VOCs should be added in typical HVAC systems. Among all of the air cleaning techniques used to remove indoor VOCs, photocatalytic oxidation is an attractive alternative technique for indoor air purification and deodorization. The objective of this research is to investigate the VOC removal efficiency of the photocatalytic filter in a HVAC system. Toluene and formaldehyde were chosen as the target pollutants. The experiments were conducted in a stainless steel chamber equipped with a simplified HVAC system. A mechanical filter coated with Degussa P25 titania photocatalyst and two commercial photocatalytic filters were used as the photocatalytic filters in this simplified HVAC system. The total air change rates were controlled at 0.5, 0.75, 1, 1.25, and 1.5 hr(-1), and the relative humidity (RH) was controlled at 30%, 50%, and 70%. The ultraviolet lamp used was a 4-W, ultraviolet-C (central wavelength at 254 nm) strip light bulb. The first-order decay constant of toluene and formaldehyde found in this study ranged from 0.381 to 1.01 hr(-1) under different total air change rates, from 0.34 to 0.433 hr(-1) under different RH, and from 0.381 to 0.433 hr(-1) for different photocatalytic filters.

Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency

DTIC Science & Technology

2016-11-21

This project involved a field demonstration of subsurface thermal energy storage for improving the geothermal heat pump air conditioning efficiency... geothermal heat pump systems, undesirable heating of the ground may occur. This demonstration was performed at the MCAS, Beaufort, SC, where several...buildings with geothermal heat pump systems were exhibiting excessively high ground loop temperatures. These buildings were retrofitted with dry fluid

Innovative Air Conditioning and Climate Control

NASA Technical Reports Server (NTRS)

Graf, John

2015-01-01

NASA needed to develop a desiccant wheel based humidity removal system to enable the long term testing of the Orion CO2 scrubber on the International Space Station. In the course of developing that system, we learned three things that are relevant to energy efficient air conditioning of office towers. NASA developed a conceptual design for a humidity removal system for an office tower environment. We are looking for interested partners to prototype and field test this concept.

Variable temperature seat climate control system

DOEpatents

Karunasiri, Tissa R.; Gallup, David F.; Noles, David R.; Gregory, Christian T.

1997-05-06

A temperature climate control system comprises a variable temperature seat, at least one heat pump, at least one heat pump temperature sensor, and a controller. Each heat pump comprises a number of Peltier thermoelectric modules for temperature conditioning the air in a main heat exchanger and a main exchanger fan for passing the conditioned air from the main exchanger to the variable temperature seat. The Peltier modules and each main fan may be manually adjusted via a control switch or a control signal. Additionally, the temperature climate control system may comprise a number of additional temperature sensors to monitor the temperature of the ambient air surrounding the occupant as well as the temperature of the conditioned air directed to the occupant. The controller is configured to automatically regulate the operation of the Peltier modules and/or each main fan according to a temperature climate control logic designed both to maximize occupant comfort during normal operation, and minimize possible equipment damage, occupant discomfort, or occupant injury in the event of a heat pump malfunction.

Cooling Computers.

ERIC Educational Resources Information Center

Birken, Marvin N.

1967-01-01

Numerous decisions must be made in the design of computer air conditioning, each determined by a combination of economics, physical, and esthetic characteristics, and computer requirements. Several computer air conditioning systems are analyzed--(1) underfloor supply and overhead return, (2) underfloor plenum and overhead supply with computer unit…

Joint Precision Approach and Landing System Nunn-McCurdy Breach Root Cause Analysis and Portfolio Assessment Metrics for DoD Weapons Systems. Volume 8

DTIC Science & Technology

2015-01-01

system that would help in adverse weather conditions. U.S. operations in Bosnia, which were run from a relatively austere airfield with limited air... operations beginning in 2013 (CVN21, Joint Strike Fighter, Joint Unmanned Combat Air System ). cAccording to multiple FAA ofcial planning documents...Positioning System Next Generation Operational Control System HMS Handheld, Manpack and Small Form Fit HUD Head up Display IAMD Integrated Air and

Improving indoor air quality and thermal comfort in office building by using combination filters

NASA Astrophysics Data System (ADS)

Kabrein, H.; Yusof, M. Z. M.; Hariri, A.; Leman, A. M.; Afandi, A.

2017-09-01

Poor indoor air quality and thermal comfort condition in the workspace affected the occupants’ health and work productivity, especially when adapting the recirculation of air in heating ventilation and air-conditioning (HVAC) system. The recirculation of air was implemented in this study by mixing the circulated returned indoor air with the outdoor fresh air. The aims of this study are to assess the indoor thermal comfort and indoor air quality (IAQ) in the office buildings, equipped with combination filters. The air filtration technique consisting minimum efficiency reporting value (MERV) filter and activated carbon fiber (ACF) filter, located before the fan coil units. The findings of the study show that the technique of mixing recirculation air with the fresh air through the combination filters met the recommended thermal comfort condition in the workspace. Furthermore, the result of the post-occupancy evaluation (POE) and the environmental measurements comply with the ASHRAE 55 standard. In addition, the level of CO2 concentration continued to decrease during the period of the measurement.

Solar Heating System installed at Belz Investment Company, Memphis, Tennessee

NASA Technical Reports Server (NTRS)

1981-01-01

A hot air solar system which utilizes flat plate air collectors is discussed. Collector areas for each of four buildings cover 780 sq ft, with storage capacity of 390 cu ft per building. The air system has a special air handling unit to move air through the collectors and into and out of the rock storage, with connection to the air duct distribution system. The heat of the motor is added to the heat delivered to the system. The solar system also includes four motorized special low leakage dampers and two gravity fabric dampers. The system is automatically controlled by a solid state controller with three thermistors: one located in the collectors, one in the rock box to plenum, one in the return air duct from the heated space. A three stage heating thermostat, located in the conditioned space, controls the operation.

An Application of the Methodology for Assessment of the Sustainability of Air Transport System

NASA Technical Reports Server (NTRS)

Janic, Milan

2003-01-01

An assessment and operationalization of the concept of sustainable air transport system is recognized as an important but complex research, operational and policy task. In the scope of the academic efforts to properly address the problem, this paper aims to assess the sustainability of air transport system. It particular, the paper describes the methodology for assessment of sustainability and its potential application. The methodology consists of the indicator systems, which relate to the air transport system operational, economic, social and environmental dimension of performance. The particular indicator systems are relevant for the particular actors such users (air travellers), air transport operators, aerospace manufacturers, local communities, governmental authorities at different levels (local, national, international), international air transport associations, pressure groups and public. In the scope of application of the methodology, the specific cases are selected to estimate the particular indicators, and thus to assess the system sustainability under given conditions.

The study of operating an air conditioning system using Maisotsenko-Cycle

NASA Astrophysics Data System (ADS)

Khan, Mohammad S.; Tahan, Sami; Toufic El-Achkar, Mohamad; Abou Jamus, Saleh

2018-03-01

The project aims to design and build an air conditioning system that runs on the Maisotsenko cycle. The system is required to condition and cool down ambient air for a small residential space with the reduction in the use of electricity and eliminating the use of commercial refrigerants. This project can operate at its optimum performance in remote areas like oil diggers and other projects that run in the desert or any site that would not have a very high relative humidity level. The Maisotsenko cycle is known as the thermodynamic concept that captures energy from the air by using the psychometric renewable energy available in the latent heat in water evaporating in air. The heat and mass exchanger design was based on choosing a material that would-be water resistant and breathable, which was found to be layers of cardboard placed on top of each other and thus creating channels for air to pass through. Aiming for this design eliminates any high power electrical equipment such as compressors, condensers and evaporators that would be used in an AC system with the exception of a 600 W blower and a 10 W fan, thus making it a more environmentally friendly project. Moreover, the project is limited by the ambient temperature and humidity, as the model operates at an optimum when the relative humidity is lower.

Natural ventilation systems to enhance sustainability in buildings: a review towards zero energy buildings in schools

NASA Astrophysics Data System (ADS)

Gil-Baez, Maite; Barrios-Padura, Ángela; Molina-Huelva, Marta; Chacartegui, Ricardo

2017-11-01

European regulations set the condition of Zero Energy Buildings for new buildings since 2020, with an intermediate milestone in 2018 for public buildings, in order to control greenhouse gases emissions control and climate change mitigation. Given that main fraction of energy consumption in buildings operation is due to HVAC systems, advances in its design and operation conditions are required. One key element for energy demand control is passive design of buildings. On this purpose, different recent studies and publications analyse natural ventilation systems potential to provide indoor air quality and comfort conditions minimizing electric power consumption. In these passive systems are of special relevance their capacities as passive cooling systems as well as air renovation systems, especially in high-density occupied spaces. With adequate designs, in warm/mild climates natural ventilation systems can be used along the whole year, maintaining indoor air quality and comfort conditions with small support of other heating/cooling systems. In this paper is analysed the state of the art of natural ventilation systems applied to high density occupied spaces with special focus on school buildings. The paper shows the potential and applicability of these systems for energy savings and discusses main criteria for their adequate integration in school building designs.

Filters from taxis air conditioning system: A tool to characterize driver's occupational exposure to bioburden?

PubMed

Viegas, Carla; Monteiro, Ana; Dos Santos, Mateus; Faria, Tiago; Caetano, Liliana Aranha; Carolino, Elisabete; Quintal Gomes, Anita; Marchand, Geneviève; Lacombe, Nancy; Viegas, Susana

2018-07-01

Bioburden proliferation in filters from air conditioning systems of taxis represents a possible source of occupational exposure. The aim of this study was to determine the occurrence of fungi and bacteria in filters from the air conditioning system of taxis used for patient transportation and to assess the exposure of drivers to bioburden. Filters from the air conditioning systems of 19 taxis and 28 personal vehicles (used as controls) operating in three Portuguese cities including the capital Lisbon, were collected during the winter season. The occurrence and significance of bioburden detected in the different vehicles are reported and discussed in terms of colony-forming units (CFU) per 1 m 2 of filter area and by the identification of the most frequently detected fungal isolates based on morphology. Azole-resistant mycobiota, fungal biomass, and molecular detection of Aspergillus species/strains were also determined. Bacterial growth was more prevalent in taxis (63.2%) than in personal vehicles (26.3%), whereas fungal growth was more prevalent in personal vehicles (53.6%) than in taxis (21.1-31.6%). Seven different azole-resistant species were identified in this study in 42.1% taxi filters. Levels of fungal biomass were above the detection limit in 63% taxi filters and in 75% personal vehicle filters. No toxigenic species were detected by molecular analysis in the assessed filters. The results obtained show that bioburden proliferation occurs widely in filters from the air conditioning systems of taxis, including the proliferation of azole-resistant fungal species, suggesting that filters should be replaced more frequently. The use of culture based-methods and molecular tools combined enabled an improved risk characterization in this setting. Copyright © 2018 Elsevier Inc. All rights reserved.

An Award Winning Design for Downtown Manhattan High School

ERIC Educational Resources Information Center

Modern Schools, 1974

1974-01-01

New York City's downtown Commercial High School will be completely air conditioned with an unusual all-air, variable air volume system that will keep students and teachers comfortable throughout the year. (Author/MF)

40 CFR 63.401 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., ventilation, or air conditioning system. Initial startup means the initiation of recirculation water flow... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for...

Recognizing Airborne Hazards.

ERIC Educational Resources Information Center

Schneider, Christian M.

1990-01-01

The heating, ventilating, and air conditioning (HVAC) systems in older buildings often do not adequately handle air-borne contaminants. Outlines a three-stage Indoor Air Quality (IAQ) assessment and describes a case in point at a Pittsburgh, Pennsylvania, school. (MLF)

Application of AirCell Cellular AMPS Network and Iridium Satellite System Dual Mode Service to Air Traffic Management

NASA Technical Reports Server (NTRS)

Shamma, Mohammed A.

2004-01-01

The AirCell/Iridium dual mode service is evaluated for potential applications to Air Traffic Management (ATM) communication needs. The AirCell system which is largely based on the Advanced Mobile Phone System (AMPS) technology, and the Iridium FDMA/TDMA system largely based on the Global System for Mobile Communications(GSM) technology, can both provide communication relief for existing or future aeronautical communication links. Both have a potential to serve as experimental platforms for future technologies via a cost effective approach. The two systems are well established in the entire CONUS and globally hence making it feasible to utilize in all regions, for all altitudes, and all classes of aircraft. Both systems have been certified for air usage. The paper summarizes the specifications of the AirCell/Iridium system, as well as the ATM current and future links, and application specifications. the paper highlights the scenarios, applications, and conditions under which the AirCell/Iridium technology can be suited for ATM Communication.

Indoor Air Quality in Schools.

ERIC Educational Resources Information Center

Torres, Vincent M.

Asserting that the air quality inside schools is often worse than outdoor pollution, leading to various health complaints and loss of productivity, this paper details factors contributing to schools' indoor air quality. These include the design, operation, and maintenance of heating, ventilating, and air conditioning (HVAC) systems; building…

Instituting a filtration/pressurization system to reduce dust concentrations in a control room at a mineral processing plant

PubMed Central

Noll, J.; Cecala, A.; Hummer, J.

2016-01-01

The National Institute for Occupational Safety and Health has observed that many control rooms and operator compartments in the U.S. mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room that had no cleaning system for intake air, a filtration and pressurization system originally designed for enclosed cabs was modified and installed. This system was composed of two filtering units: one to filter outside air and one to filter and recirculate the air inside the control room. Eighty-seven percent of submicrometer particles were reduced by the system under static conditions. This means that greater than 87 percent of respirable dust particles should be reduced as the particle-size distribution of respirable dust particles is greater than that of submicrometer particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced, which is an important component of an effective system and minimizes the entry of particles, such as dust, into the room. The intake airflow was around 118 cfm, greater than the airflow suggested by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for acceptable indoor air quality. After one year, the loading of the filter caused the airflow to decrease to 80 cfm, which still produces acceptable indoor air quality. Due to the loading of the filters, the reduction efficiency for submicrometer particles under static conditions increased to 94 percent from 87 percent. PMID:26834293

Control systems for heating, ventilating, and air conditioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haines, R.W.

1977-01-01

Hundreds of ideas for designing and controlling sophisticated heating, ventilating and air conditioning (HVAC) systems are presented. Information is included on enthalpy control, energy conservation in HVAC systems, on solar heating, cooling and refrigeration systems, and on a self-draining water collector and heater. Computerized control systems and the economics of supervisory systems are discussed. Information is presented on computer system components, software, relevant terminology, and computerized security and fire reporting systems. Benefits of computer systems are explained, along with optimization techniques, data management, maintenance schedules, and energy consumption. A bibliography, glossaries of HVAC terminology, abbreviations, symbols, and a subject indexmore » are provided. (LCL)« less

[Age factor in a complex evaluation of health of air staff].

PubMed

Ushakov, I B; Batishcheva, G A; Chernov, Iu N; Khomenko, M N; Soldatov, S K

2010-03-01

Was elaborated program of a complex of estimation of health condition of air staff with determination of capability of early diagnostic of functional tension of physiological systems. According to this system there were observed 73 airmen using a complex of tests (estimation of level of pectoral control, of personal and reactive anxiety, vegetal regulation etc.). Was detected, that length of service and sympato-adrenaline activeness with vicarious decrease of adrenoreactiveness are in direct proportion. Were marked the most informative indexes of estimation of functional tension of psycho-physiological functions, vegetative regulation and cardiovascular system. Was shown that the elaborated system of individual estimation of health of air staff permits diagnose prenosological conditions and determine indexes for rehabilitation treatment.

Modeling Hybrid Nuclear Systems With Chilled-Water Storage

DOE PAGES

Misenheimer, Corey T.; Terry, Stephen D.

2016-06-27

Air-conditioning loads during the warmer months of the year are large contributors to an increase in the daily peak electrical demand. Traditionally, utility companies boost output to meet daily cooling load spikes, often using expensive and polluting fossil fuel plants to match the demand. Likewise, heating, ventilation, and air conditioning (HVAC) system components must be sized to meet these peak cooling loads. However, the use of a properly sized stratified chilled-water storage system in conjunction with conventional HVAC system components can shift daily energy peaks from cooling loads to off-peak hours. This process is examined in light of the recentmore » development of small modular nuclear reactors (SMRs). In this paper, primary components of an air-conditioning system with a stratified chilled-water storage tank were modeled in FORTRAN 95. A basic chiller operation criterion was employed. Simulation results confirmed earlier work that the air-conditioning system with thermal energy storage (TES) capabilities not only reduced daily peaks in energy demand due to facility cooling loads but also shifted the energy demand from on-peak to off-peak hours, thereby creating a more flattened total electricity demand profile. Thus, coupling chilled-water storage-supplemented HVAC systems to SMRs is appealing because of the decrease in necessary reactor power cycling, and subsequently reduced associated thermal stresses in reactor system materials, to meet daily fluctuations in cooling demand. Finally and also, such a system can be used as a thermal sink during reactor transients or a buffer due to renewable intermittency in a nuclear hybrid energy system (NHES).« less

Modeling Hybrid Nuclear Systems With Chilled-Water Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Misenheimer, Corey T.; Terry, Stephen D.

Air-conditioning loads during the warmer months of the year are large contributors to an increase in the daily peak electrical demand. Traditionally, utility companies boost output to meet daily cooling load spikes, often using expensive and polluting fossil fuel plants to match the demand. Likewise, heating, ventilation, and air conditioning (HVAC) system components must be sized to meet these peak cooling loads. However, the use of a properly sized stratified chilled-water storage system in conjunction with conventional HVAC system components can shift daily energy peaks from cooling loads to off-peak hours. This process is examined in light of the recentmore » development of small modular nuclear reactors (SMRs). In this paper, primary components of an air-conditioning system with a stratified chilled-water storage tank were modeled in FORTRAN 95. A basic chiller operation criterion was employed. Simulation results confirmed earlier work that the air-conditioning system with thermal energy storage (TES) capabilities not only reduced daily peaks in energy demand due to facility cooling loads but also shifted the energy demand from on-peak to off-peak hours, thereby creating a more flattened total electricity demand profile. Thus, coupling chilled-water storage-supplemented HVAC systems to SMRs is appealing because of the decrease in necessary reactor power cycling, and subsequently reduced associated thermal stresses in reactor system materials, to meet daily fluctuations in cooling demand. Finally and also, such a system can be used as a thermal sink during reactor transients or a buffer due to renewable intermittency in a nuclear hybrid energy system (NHES).« less

High efficiency stoichiometric internal combustion engine system

DOEpatents

Winsor, Richard Edward; Chase, Scott Allen

2009-06-02

A power system including a stoichiometric compression ignition engine in which a roots blower is positioned in the air intake for the engine to control air flow. Air flow is decreased during part power conditions to maintain the air-fuel ratio in the combustion chamber of the engine at stoichiometric, thus enabling the use of inexpensive three-way catalyst to reduce oxides of nitrogen. The roots blower is connected to a motor generator so that when air flow is reduced, electrical energy is stored which is made available either to the roots blower to temporarily increase air flow or to the system electrical load and thus recapture energy that would otherwise be lost in reducing air flow.

Automatic humidification system to support the assessment of food drying processes

NASA Astrophysics Data System (ADS)

Ortiz Hernández, B. D.; Carreño Olejua, A. R.; Castellanos Olarte, J. M.

2016-07-01

This work shows the main features of an automatic humidification system to provide drying air that match environmental conditions of different climate zones. This conditioned air is then used to assess the drying process of different agro-industrial products at the Automation and Control for Agro-industrial Processes Laboratory of the Pontifical Bolivarian University of Bucaramanga, Colombia. The automatic system allows creating and improving control strategies to supply drying air under specified conditions of temperature and humidity. The development of automatic routines to control and acquire real time data was made possible by the use of robust control systems and suitable instrumentation. The signals are read and directed to a controller memory where they are scaled and transferred to a memory unit. Using the IP address is possible to access data to perform supervision tasks. One important characteristic of this automatic system is the Dynamic Data Exchange Server (DDE) to allow direct communication between the control unit and the computer used to build experimental curves.

Acanthamoeba belonging to T3, T4, and T11: genotypes isolated from air-conditioning units in Santiago, Chile.

PubMed

Astorga, Berbeli; Lorenzo-Morales, Jacob; Martín-Navarro, Carmen M; Alarcón, Verónica; Moreno, Johanna; González, Ana C; Navarrete, Elizabeth; Piñero, José E; Valladares, Basilio

2011-01-01

Free-living amoebae (FLA) of the genus Acanthamoeba are widely distributed in the environment, in the air, soil, and water, and have also been isolated from air-conditioning units. The objective of this work was to investigate the presence of this genus of FLA in the air-conditioning equipment at the Institute of Public Health of Chile in Santiago, Chile. Water and air samples were collected from air-conditioning systems and were checked for the presence of Acanthamoeba spp. Positive samples were further classified at the genotype level after sequencing the highly variable diagnostic fragment 3 (DF3) region of the 18S rRNA gene. This is the first report of the T3, T4, and T11 genotypes of Acanthamoeba in air-conditioning units from Chile. Overall, the widespread distribution of potentially pathogenic Acanthamoeba strains in the studied source demands more awareness within the public and health professionals in Chile as this pathogen is emerging as a risk for human health worldwide. © 2011 The Author(s) Journal of Eukaryotic Microbiology © 2011 International Society of Protistologists.

Adsorption of PFOA at the Air-Water Interface during Transport in Unsaturated Porous Media.

PubMed

Lyu, Ying; Brusseau, Mark L; Chen, Wei; Yan, Ni; Fu, Xiaori; Lin, Xueyu

2018-06-26

Miscible-displacement experiments are conducted with perfluorooctanoic acid (PFOA) to determine the contribution of adsorption at the air-water interface to retention during transport in water-unsaturated porous media. Column experiments were conducted with two sands of different diameter at different PFOA input concentrations, water saturations, and pore-water velocities to evaluate the impact of system variables on retardation. The breakthrough curves for unsaturated conditions exhibited greater retardation than those obtained for saturated conditions, demonstrating the significant impact of air-water interfacial adsorption on PFOA retention. Retardation was greater for lower water saturations and smaller grain diameter, consistent with the impact of system conditions on the magnitude of air-water interfacial area in porous media. Retardation was greater for lower input concentrations of PFOA for a given water saturation, consistent with the nonlinear nature of surfactant fluid-fluid interfacial adsorption. Retardation factors predicted using independently determined parameter values compared very well to the measured values. The results showed that adsorption at the air-water interface is a significant source of retention for PFOA, contributing approximately 50-75% of total retention, for the test systems. The significant magnitude of air-water interfacial adsorption measured in this work has ramifications for accurate determination of PFAS migration potential in vadose zones.

Experimental investigation of static ice refrigeration air conditioning system driven by distributed photovoltaic energy system

NASA Astrophysics Data System (ADS)

Xu, Y. F.; Li, M.; Luo, X.; Wang, Y. F.; Yu, Q. F.; Hassanien, R. H. E.

2016-08-01

The static ice refrigeration air conditioning system (SIRACS) driven by distributed photovoltaic energy system (DPES) was proposed and the test experiment have been investigated in this paper. Results revealed that system energy utilization efficiency is low because energy losses were high in ice making process of ice slide maker. So the immersed evaporator and co-integrated exchanger were suggested in system structure optimization analysis and the system COP was improved nearly 40%. At the same time, we have researched that ice thickness and ice super-cooled temperature changed along with time and the relationship between system COP and ice thickness was obtained.

Section 609 Technician Training and Certification Programs

EPA Pesticide Factsheets

EPA-approved programs for technicians who service motor vehicle air conditioning (MVAC) systems. Any person who repairs or services a MVAC system for consideration must be certified under section 609 of the Clean Air Act by an EPA-approved program.

49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

Code of Federal Regulations, 2014 CFR

2014-10-01

... normal operating temperature. (5) The heating, ventilation and air conditioning (HVAC) system or a dedicated heating or air conditioner system must be operating on high, and the vents must be open and...

49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

Code of Federal Regulations, 2013 CFR

2013-10-01

... normal operating temperature. (5) The heating, ventilation and air conditioning (HVAC) system or a dedicated heating or air conditioner system must be operating on high, and the vents must be open and...

49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

Code of Federal Regulations, 2012 CFR

2012-10-01

... normal operating temperature. (5) The heating, ventilation and air conditioning (HVAC) system or a dedicated heating or air conditioner system must be operating on high, and the vents must be open and...

49 CFR Appendix H to Part 229 - Static Noise Test Protocols-In-Cab Static

Code of Federal Regulations, 2011 CFR

2011-10-01

... normal operating temperature. (5) The heating, ventilation and air conditioning (HVAC) system or a dedicated heating or air conditioner system must be operating on high, and the vents must be open and...

31. View of mezzanine floor level in transmitter building no. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. View of mezzanine floor level in transmitter building no. 102 showing various electronic central indicator panel to control building air conditioning, steam pressure, supply temperature, discharge temperature, supply pressure, transformer vault status, and radome conditioning system. - Clear Air Force Station, Ballistic Missile Early Warning System Site II, One mile west of mile marker 293.5 on Parks Highway, 5 miles southwest of Anderson, Anderson, Denali Borough, AK

Deep Desulfurization of Diesel Fuels with Plasma/Air as Oxidizing Medium, Diperiodatocuprate (III) as Catalyzer and Ionic Liquid as Extraction Solvent

NASA Astrophysics Data System (ADS)

Ban, Lili; Liu, Ping; Ma, Cunhua; Dai, Bin

2013-12-01

In this paper, the oxidative desulfurization (ODS) system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge (DBD) plasma in the presence of air plus an extraction step with the oxidation-treated fuel put over ionic liquid [BMIM]FeCl4 (1-butyl-3-methylimidazolium tetrachloroferrate). This new system exhibited an excellent desulfurization effect. The sulfur content of DBT in diesel oil decreased from 200 ppm to 4.92 ppm (S removal rate up to 97.5%) under the following optimal reaction conditions: air flow rate (ν) of 60 mL/min, amplitude of applied voltage (U) on DBD of 16 kV, input frequency (f) of 79 kHz, catalyst amount (ω) of 1.25 wt%, reaction time (t) of 10 min. Moreover, a high desulfurization rate was obtained during oxidation of benzothiophene (BT) or 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) under the aforementioned conditions. The oxidation reactivity of different S compounds was decreased in the order of DBT, 4,6-DMDBT and BT. The remarkable advantage of the novel ODS system is that the desulfurization condition applies in the presence of air at ambient conditions without peroxides, aqueous solvent or biphasic oil-aqueous solution system.

HVAC System Automatic Controls and Indoor Air Quality in Schools. Technical Bulletin.

ERIC Educational Resources Information Center

Wheeler, Arthur E.

Fans, motors, coils, and other control components enable a heating, ventilating, and air-conditioning (HVAC) system to function smoothly. An explanation of these control components and how they make school HVAC systems work is provided. Different systems may be compared by counting the number of controlled devices that are required. Control…

75 FR 43092 - Airworthiness Directives; Viking Air Limited (Type Certificate Previously Held by Bombardier, Inc...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-23

... completed a system safety review of the aircraft fuel system against fuel tank safety standards introduced... Limited has completed a system safety review of the aircraft fuel system against fuel tank safety... describes the unsafe condition as: Viking Air Limited has completed a system safety review of the aircraft...

LiCl Dehumidifier LiBr absorption chiller hybrid air conditioning system with energy recovery

DOEpatents

Ko, Suk M.

1980-01-01

This invention relates to a hybrid air conditioning system that combines a solar powered LiCl dehumidifier with a LiBr absorption chiller. The desiccant dehumidifier removes the latent load by absorbing moisture from the air, and the sensible load is removed by the absorption chiller. The desiccant dehumidifier is coupled to a regenerator and the desiccant in the regenerator is heated by solar heated hot water to drive the moisture therefrom before being fed back to the dehumidifier. The heat of vaporization expended in the desiccant regenerator is recovered and used to partially preheat the driving fluid of the absorption chiller, thus substantially improving the overall COP of the hybrid system.

THE EFFECTS OF BUILDING FEATURES ON INDOOR AIR AND POLLUTANT MOVEMENTS

EPA Science Inventory

The paper discusses full-scale residential building tests to determine the effects of building features on indoor air and pollutant movement. It was found that the activated heating and air-conditioning (HAC) system served as a conductor that enhanced the indoor air movement and ...

HPAC Info-dex 2: Locating a product

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-06-01

This is the 1995/1996 listing of products for heating, ventilation, air conditioning and refrigeration systems published by Heating, Piping, and Air Conditioning magazine. The manufacturers are listed alphabetically along with their abbreviated address and telephone and FAX numbers. Some product information is included for certain manufacturers.

Flight control with adaptive critic neural network

NASA Astrophysics Data System (ADS)

Han, Dongchen

2001-10-01

In this dissertation, the adaptive critic neural network technique is applied to solve complex nonlinear system control problems. Based on dynamic programming, the adaptive critic neural network can embed the optimal solution into a neural network. Though trained off-line, the neural network forms a real-time feedback controller. Because of its general interpolation properties, the neurocontroller has inherit robustness. The problems solved here are an agile missile control for U.S. Air Force and a midcourse guidance law for U.S. Navy. In the first three papers, the neural network was used to control an air-to-air agile missile to implement a minimum-time heading-reverse in a vertical plane corresponding to following conditions: a system without constraint, a system with control inequality constraint, and a system with state inequality constraint. While the agile missile is a one-dimensional problem, the midcourse guidance law is the first test-bed for multiple-dimensional problem. In the fourth paper, the neurocontroller is synthesized to guide a surface-to-air missile to a fixed final condition, and to a flexible final condition from a variable initial condition. In order to evaluate the adaptive critic neural network approach, the numerical solutions for these cases are also obtained by solving two-point boundary value problem with a shooting method. All of the results showed that the adaptive critic neural network could solve complex nonlinear system control problems.

Towards energy efficient operation of Heating, Ventilation and Air Conditioning systems via advanced supervisory control design

NASA Astrophysics Data System (ADS)

Oswiecinska, A.; Hibbs, J.; Zajic, I.; Burnham, K. J.

2015-11-01

This paper presents conceptual control solution for reliable and energy efficient operation of heating, ventilation and air conditioning (HVAC) systems used in large volume building applications, e.g. warehouse facilities or exhibition centres. Advanced two-level scalable control solution, designed to extend capabilities of the existing low-level control strategies via remote internet connection, is presented. The high-level, supervisory controller is based on Model Predictive Control (MPC) architecture, which is the state-of-the-art for indoor climate control systems. The innovative approach benefits from using passive heating and cooling control strategies for reducing the HVAC system operational costs, while ensuring that required environmental conditions are met.

Understanding Air-Liquid Interface Cell Exposure Systems: A Comprehensive Assessment of Various Systems Under Identical Conditions

EPA Science Inventory

Exposure of cells to atmospheric pollutants at the air-liquid interface (ALI) is a more realistic approach than exposures of attached cells submerged in liquid medium. However, there is still limited understanding of the ideal ALI system design features that permit reproducible a...

Breathing Easier: HVAC Specifications for Schools.

ERIC Educational Resources Information Center

Trent, C. Curtis; Trent, Warren C.

1996-01-01

A major source of indoor air contamination in schools originates within the heating, ventilating, and air-conditioning systems (HVAC), with draw-through systems being the worst offenders. Lists provisions for designing an HVAC system and a set of criteria to adhere to when planning new construction or renovations. (nine references) (MLF)

The research and application of green computer room environmental monitoring system based on internet of things technology

NASA Astrophysics Data System (ADS)

Wei, Wang; Chongchao, Pan; Yikai, Liang; Gang, Li

2017-11-01

With the rapid development of information technology, the scale of data center increases quickly, and the energy consumption of computer room also increases rapidly, among which, energy consumption of air conditioning cooling makes up a large proportion. How to apply new technology to reduce the energy consumption of the computer room becomes an important topic of energy saving in the current research. This paper study internet of things technology, and design a kind of green computer room environmental monitoring system. In the system, we can get the real-time environment data from the application of wireless sensor network technology, which will be showed in a creative way of three-dimensional effect. In the environment monitor, we can get the computer room assets view, temperature cloud view, humidity cloud view, microenvironment view and so on. Thus according to the condition of the microenvironment, we can adjust the air volume, temperature and humidity parameters of the air conditioning for the individual equipment cabinet to realize the precise air conditioning refrigeration. And this can reduce the energy consumption of air conditioning, as a result, the overall energy consumption of the green computer room will reduce greatly. At the same time, we apply this project in the computer center of Weihai, and after a year of test and running, we find that it took a good energy saving effect, which fully verified the effectiveness of this project on the energy conservation of the computer room.

Section 609 of the Clean Air Act: MVAC

EPA Pesticide Factsheets

Fact sheet provides a general overview of EPA regulations under Section 609 of the Clean Air Act, which is focused on preventing the release of refrigerants during the servicing of motor vehicle air-conditioning systems and similar appliances.

Vapor compression heat pump system field tests at the TECH complex

NASA Astrophysics Data System (ADS)

Baxter, V. D.

1985-07-01

The Tennessee Energy Conservation In Housing (TECH) complex has been utilized since 1977 as a field test site for several novel and conventional heat pump systems for space conditioning and water heating. Systems tested include the Annual Cycle Energy System (ACES), solar assisted heat pumps (SAHP) both parallel and series, two conventional air-to-air heat pumps, an air-to-air heat pump with desuperheater water heater, and horizontal coil and multiple shallow vertical coil ground-coupled heat pumps (GCHP). A direct comparison of the measured annual performance of the test systems was not possible. However, a cursory examination revealed that the ACES had the best performance. However, its high cost makes it unlikely that it will achieve widespread use. Costs for the SAHP systems are similar to those of the ACES but their performance is not as good. Integration of water heating and space conditioning functions with a desuperheater yielded significant efficiency improvement at modest cost. The GCHP systems performed much better for heating than for cooling and may well be the most efficient alternative for residences in cold climates.

Vapor compression heat pump system field tests at the tech complex

NASA Astrophysics Data System (ADS)

Baxter, Van D.

1985-11-01

The Tennessee Energy Conservation In Housing (TECH) complex has been utilized since 1977 as a field test site for several novel and conventional heat pump systems for space conditioning and water heating. Systems tested include the Annual Cycle Energy System (ACES), solar assisted heat pumps (SAHP) both parallel and series, two conventional air-to-air heat pumps, an air-to-air heat pump with desuperheater water heater, and horizontal coil and multiple shallow vertical coil ground-coupled heat pumps (GCHP). A direct comparison of the measured annual performance of the test systems was not possible. However, a cursory examination revealed that the ACES had the best performance, however, its high cost makes it unlikely that it will achieve wide-spread use. Costs for the SAHP systems are similar to those of the ACES but their performance is not as good. Integration of water heating and space conditioning functions with a desuperheater yielded significant efficiency improvement at modest cost. The GCHP systems performed much better for heating than for cooling and may well be the most efficient alternative for residences in cold climates.

A two-dimensional air-to-air combat game - Toward an air-combat advisory system

NASA Technical Reports Server (NTRS)

Neuman, Frank

1987-01-01

Air-to-air combat is modeled as a discrete differential game, and by constraining the game to searching for the best guidance laws from the sets of those considered for each opponent, feedback and outcome charts are obtained which can be used to turn one of the automatic opponents into an intelligent opponent against a human pilot. A one-on-one two-dimensional fully automatic, or manned versus automatic, air-to-air combat game has been designed which includes both attack and evasion alternatives for both aircraft. Guidance law selection occurs by flooding the initial-condition space with four simulated fights for each initial condition, depicting the various attack/evasion strategies for the two opponents, and recording the outcomes. For each initial condition, the minimax method from differential games is employed to determine the best choice from the available strategies.

[ESTIMATION OF THE EFFICIENCY OF THE TREATMENT OF SPLIT-SYSTEMS IN RESIDENTIAL AREAS IN ORDER TO REDUCE THE LEVEL OF THE PREVALENCE OF DISEASES OF THE RESPIRATORY SYSTEM].

PubMed

Rakhmanin Yu A; Shibanov, S E; Kozulya, S V

2016-01-01

The purpose of work: comparison of prevalence among residents, which use or fail to use to clean split systems. Collected information about morbidity rate in 235 cases people during 3 years. The usage of split-systems without their regular cleaning leads to the gain in the level of the prevalence of respiratory diseases by 172.7% if compared with persons, who have no air conditioning systems at home. Also, the average number of disability days increases by 218.1%) and average time of the duration of the disease increases by 71.9%. The annual treatment of split-systems and regular cleaning of filters allowed to reduce the number of diseases. In comparison with the group of people, who fail to clean air conditioning systems, the drop of morbidity rate by 56.6%, average number of disability days by 63.3% and average time of diseases by 30.9% was observed. Regular treatment of air conditioning systems cannot completely repay the morbidity rates to the level of the control group. In comparison with the people, who use no air conditioning systems, the owners of split-systems with regular treatment have lung diseases by 18.4% more often. The average number of disability days and the average time of diseases increased by 16.9% and 18.8%. These changes can be explained by the impact of unfavorable (cooling) microclimate. The impact of split-systems on the health of the population requires a comprehensive study and the subsequent development of normative documents regulating their safe use.

HPAC Info-dex 1: Locating a manufacturer

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-06-01

This is the 1995/1996 listing of manufacturers of products for heating, ventilation, air conditioning and refrigeration systems published by Heating, Piping, and Air Conditioning magazine. The manufacturers are listed alphabetically along with their complete addresses and telephone and FAX numbers. Some product information is included for certain manufacturers.

FAULT TREE ANALYSIS FOR EXPOSURE TO REFRIGERANTS USED FOR AUTOMOTIVE AIR CONDITIONING IN THE U.S.

EPA Science Inventory

A fault tree analysis was used to estimate the number of refrigerant exposures of automotive service technicians and vehicle occupants in the United States. Exposures of service technicians can occur when service equipment or automotive air-conditioning systems leak during servic...

Air Conditioning, Heating, and Refrigeration: Scope and Sequence.

ERIC Educational Resources Information Center

Nashville - Davidson County Metropolitan Public Schools, TN.

This scope and sequence guide, developed for an air conditioning, heating, and refrigeration vocational education program, represents an initial step in the development of a systemwide articulated curriculum sequence for all vocational programs within the Metropolitan Nashville Public School System. It was developed as a result of needs expressed…

Crawl space assisted heat pump. [using stored ground heat

NASA Technical Reports Server (NTRS)

Ternes, M. P.

1980-01-01

A variety of experiments and simulations, currently being designed or underway, to determine the feasibility of conditioning the source air of an air to air heat pump using stored ground heat or cool to produce higher seasonal COP's and net energy savings are discussed. The ground would condition ambient air as it is drawn through the crawl space of a house. Tests designed to evaluate the feasibility of the concept, to determine the amount of heat or cool available from the ground, to study the effect of the system on the heating and cooling loads of the house, to study possible mechanisms which could enhance heat flow through the ground, and to determine if diurnal temperature swings are necessary to achieve successful system performance are described.

Characterization of Francisella species isolated from the cooling water of an air conditioning system.

PubMed

Gu, Quan; Li, Xunde; Qu, Pinghua; Hou, Shuiping; Li, Juntao; Atwill, Edward R; Chen, Shouyi

2015-01-01

Strains of Francisella spp. were isolated from cooling water from an air conditioning system in Guangzhou, China. These strains are Gram negative, coccobacilli, non-motile, oxidase negative, catalase negative, esterase and lipid esterase positive. In addition, these bacteria grow on cysteine-supplemented media at 20 °C to 40 °C with an optimal growth temperature of 30 °C. Analysis of 16S rRNA gene sequences revealed that these strains belong to the genus Francisella. Biochemical tests and phylogenetic and BLAST analyses of 16S rRNA, rpoB and sdhA genes indicated that one strain was very similar to Francisella philomiragia and that the other strains were identical or highly similar to the Francisella guangzhouensis sp. nov. strain 08HL01032 we previously described. Biochemical and molecular characteristics of these strains demonstrated that multiple Francisella species exist in air conditioning systems.

Characterization of urban air quality using GIS as a management system.

PubMed

Puliafito, E; Guevara, M; Puliafito, C

2003-01-01

Keeping the air quality acceptable has become an important task for decision makers as well as for non-governmental organizations. Particulate and gaseous emissions of pollutant from industries and auto-exhausts are responsible for rising discomfort, increasing airway diseases, decreasing productivity and the deterioration of artistic and cultural patrimony in urban centers. A model to determine the air quality in urban areas using a geographical information system will be presented here. This system permits the integration, handling, analysis and simulation of spatial and temporal data of the ambient concentration of the main pollutant. It allows the users to characterize and recognize areas with a potential increase or improvement in its air pollution situation. It is also possible to compute past or present conditions by changing basic input information as traffic flow, or stack emission rates. Additionally the model may be used to test the compliance of local standard air quality, to study the environmental impact of new industries or to determine the changes in the conditions when the vehicle circulation is increased.

Development and Design of a User Interface for a Computer Automated Heating, Ventilation, and Air Conditioning System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, B.; /Fermilab

1999-10-08

A user interface is created to monitor and operate the heating, ventilation, and air conditioning system. The interface is networked to the system's programmable logic controller. The controller maintains automated control of the system. The user through the interface is able to see the status of the system and override or adjust the automatic control features. The interface is programmed to show digital readouts of system equipment as well as visual queues of system operational statuses. It also provides information for system design and component interaction. The interface is made easier to read by simple designs, color coordination, and graphics.more » Fermi National Accelerator Laboratory (Fermi lab) conducts high energy particle physics research. Part of this research involves collision experiments with protons, and anti-protons. These interactions are contained within one of two massive detectors along Fermilab's largest particle accelerator the Tevatron. The D-Zero Assembly Building houses one of these detectors. At this time detector systems are being upgraded for a second experiment run, titled Run II. Unlike the previous run, systems at D-Zero must be computer automated so operators do not have to continually monitor and adjust these systems during the run. Human intervention should only be necessary for system start up and shut down, and equipment failure. Part of this upgrade includes the heating, ventilation, and air conditioning system (HVAC system). The HVAC system is responsible for controlling two subsystems, the air temperatures of the D-Zero Assembly Building and associated collision hall, as well as six separate water systems used in the heating and cooling of the air and detector components. The BYAC system is automated by a programmable logic controller. In order to provide system monitoring and operator control a user interface is required. This paper will address methods and strategies used to design and implement an effective user interface. Background material pertinent to the BYAC system will cover the separate water and air subsystems and their purposes. In addition programming and system automation will also be covered.« less

Retrofitting Air Conditioning and Duct Systems in Hot, Dry Climates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shapiro, C.; Aldrich, R.; Arena, L.

2012-07-01

This technical report describes CARB's work with Clark County Community Resources Division in Las Vegas, Nevada, to optimize procedures for upgrading cooling systems on existing homes in the area to implement health, safety, and energy improvements. Detailed monitoring of five AC systems showed that three of the five systems met or exceeded air flow rate goals.

Development of ZL400 Mine Cooling Unit Using Semi-Hermetic Screw Compressor and Its Application on Local Air Conditioning in Underground Long-Wall Face

NASA Astrophysics Data System (ADS)

Chu, Zhaoxiang; Ji, Jianhu; Zhang, Xijun; Yan, Hongyuan; Dong, Haomin; Liu, Junjie

2016-12-01

Aiming at heat injuries occurring in the process of deep coal mining in China, a ZL400 mine-cooling unit employing semi-hermetic screw compressor with a cooling capacity of 400 kW is developed. This paper introduced its operating principle, structural characteristics and technical indexes. By using the self-built testing platform, some parameters for indication of its operation conditions were tested on the ground. The results show that the aforementioned cooling unit is stable in operation: cooling capacity of the unit was 420 kW underground-test conditions, while its COP (coefficient of performance) reached 3.4. To address the issue of heat injuries existing in No. 16305 U-shaped long-wall ventilation face of Jining No. 3 coal mine, a local air conditioning system was developed with ZL400 cooling unit as the system's core. The paper presented an analysis of characteristics of the air current flowing in the air-mixing and cooling mode of ZL400 cooling unit used in air intake way. Through i-d patterns we described the process of the airflow treatment, such as cooling, mixing and heating, etc. The cooling system decreased dry bulb temperature on working face by 3°C on average and 3.8°C at most, while lowered the web bulb temperature by 3.6°C on average and 4.8°C at most. At the same time, it reduced relative humidity by 5% on average and 8.6% at most. The field application of the ZL400 cooling unit had gain certain effects in air conditioning and provided support for the solution of mine heat injuries in China in terms of technology and equipment.

Fault tree analysis for exposure to refrigerants used for automotive air conditioning in the United States.

PubMed

Jetter, J J; Forte, R; Rubenstein, R

2001-02-01

A fault tree analysis was used to estimate the number of refrigerant exposures of automotive service technicians and vehicle occupants in the United States. Exposures of service technicians can occur when service equipment or automotive air-conditioning systems leak during servicing. The number of refrigerant exposures of service technicians was estimated to be 135,000 per year. Exposures of vehicle occupants can occur when refrigerant enters passenger compartments due to sudden leaks in air-conditioning systems, leaks following servicing, or leaks caused by collisions. The total number of exposures of vehicle occupants was estimated to be 3,600 per year. The largest number of exposures of vehicle occupants was estimated for leaks caused by collisions, and the second largest number of exposures was estimated for leaks following servicing. Estimates used in the fault tree analysis were based on a survey of automotive air-conditioning service shops, the best available data from the literature, and the engineering judgement of the authors and expert reviewers from the Society of Automotive Engineers Interior Climate Control Standards Committee. Exposure concentrations and durations were estimated and compared with toxicity data for refrigerants currently used in automotive air conditioners. Uncertainty was high for the estimated numbers of exposures, exposure concentrations, and exposure durations. Uncertainty could be reduced in the future by conducting more extensive surveys, measurements of refrigerant concentrations, and exposure monitoring. Nevertheless, the analysis indicated that the risk of exposure of service technicians and vehicle occupants is significant, and it is recommended that no refrigerant that is substantially more toxic than currently available substitutes be accepted for use in vehicle air-conditioning systems, absent a means of mitigating exposure.

75. GENERAL VIEW OF PORTABLE PAYLOAD AIRCONDITIONING SYSTEM LOCATED ON ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

75. GENERAL VIEW OF PORTABLE PAYLOAD AIR-CONDITIONING SYSTEM LOCATED ON NORTH SIDE OF SLC-3W LIQUID OXYGEN APRON - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

22. DETAIL OF CHILLERS 1 AND 2 (MST AIRCONDITIONING SYSTEM) ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. DETAIL OF CHILLERS 1 AND 2 (MST AIR-CONDITIONING SYSTEM) INTERIOR, NORTHEAST CORNER, STATION 30, SLC-3W MST - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Low-Flow Liquid Desiccant Air-Conditioning: Demonstrated Performance and Cost Implications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozubal, E.; Herrmann, L.; Deru, M.

2014-09-01

Cooling loads must be dramatically reduced when designing net-zero energy buildings or other highly efficient facilities. Advances in this area have focused primarily on reducing a building's sensible cooling loads by improving the envelope, integrating properly sized daylighting systems, adding exterior solar shading devices, and reducing internal heat gains. As sensible loads decrease, however, latent loads remain relatively constant, and thus become a greater fraction of the overall cooling requirement in highly efficient building designs, particularly in humid climates. This shift toward latent cooling is a challenge for heating, ventilation, and air-conditioning (HVAC) systems. Traditional systems typically dehumidify by firstmore » overcooling air below the dew-point temperature and then reheating it to an appropriate supply temperature, which requires an excessive amount of energy. Another dehumidification strategy incorporates solid desiccant rotors that remove water from air more efficiently; however, these systems are large and increase fan energy consumption due to the increased airside pressure drop of solid desiccant rotors. A third dehumidification strategy involves high flow liquid desiccant systems. These systems require a high maintenance separator to protect the air distribution system from corrosive desiccant droplet carryover and so are more commonly used in industrial applications and rarely in commercial buildings. Both solid desiccant systems and most high-flow liquid desiccant systems (if not internally cooled) add sensible energy which must later be removed to the air stream during dehumidification, through the release of sensible heat during the sorption process.« less

Field test and simulation evaluation of variable refrigerant flow systems performance

DOE PAGES

Lee, Je Hyeon; Im, Piljae; Song, Young-hak

2017-10-24

Our study aims to compare the performance of a Variable Refrigerant Flow (VRF) system with a Roof Top Unit, (RTU) and a variable-air-volume (VAV) system through field tests and energy simulations. The field test was conducted in as similar conditions as possible between the two systems, such as the installation and operating environments of heating, the ventilation and air conditioning (HVAC) system, including internal heat gain and outdoor conditions, including buildings to compare the performance of the two systems accurately. A VRF system and RTU were installed at the test building located in Oak Ridge, Tennessee, in the USA. Themore » same internal heat gain was generated at the same operating time of the two systems using lighting, electric heaters, and humidifiers inside the building. The HVAC system was alternately operated between cooling and heating operations to acquire energy performance data and to compare energy usage. Furthermore, an hourly building energy simulation model was developed with regard to the VRF system and RTU, and then the model was calibrated using actual measured data. Then, annual energy consumption of the two systems were compared and analyzed using the calibrated model. Moreover, additional analysis was conducted when the controlled discharge air temperature in the RTU was changed. The field test result showed that when energy consumptions of two systems were compared at the same outdoor conditions, using the weather-normalized model, the VRF system exhibited an energy reduction of approximately 17% during cooling operation and of approximately 74% during heating operations. A comparison on the annual energy consumption using simulations showed that the VRF system reduced energy consumption more than that of the RTU by 60%. Furthermore, when the discharge air temperature in the RTU was controlled according to the outdoor air temperature, energy consumption of the RTU was reduced by 6% in cooling operations and by 18% in heating operation. As a result, energy consumption of the VRF system was reduced by more than that of the RTU by 55% approximately.« less

Field test and simulation evaluation of variable refrigerant flow systems performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Je Hyeon; Im, Piljae; Song, Young-hak

Our study aims to compare the performance of a Variable Refrigerant Flow (VRF) system with a Roof Top Unit, (RTU) and a variable-air-volume (VAV) system through field tests and energy simulations. The field test was conducted in as similar conditions as possible between the two systems, such as the installation and operating environments of heating, the ventilation and air conditioning (HVAC) system, including internal heat gain and outdoor conditions, including buildings to compare the performance of the two systems accurately. A VRF system and RTU were installed at the test building located in Oak Ridge, Tennessee, in the USA. Themore » same internal heat gain was generated at the same operating time of the two systems using lighting, electric heaters, and humidifiers inside the building. The HVAC system was alternately operated between cooling and heating operations to acquire energy performance data and to compare energy usage. Furthermore, an hourly building energy simulation model was developed with regard to the VRF system and RTU, and then the model was calibrated using actual measured data. Then, annual energy consumption of the two systems were compared and analyzed using the calibrated model. Moreover, additional analysis was conducted when the controlled discharge air temperature in the RTU was changed. The field test result showed that when energy consumptions of two systems were compared at the same outdoor conditions, using the weather-normalized model, the VRF system exhibited an energy reduction of approximately 17% during cooling operation and of approximately 74% during heating operations. A comparison on the annual energy consumption using simulations showed that the VRF system reduced energy consumption more than that of the RTU by 60%. Furthermore, when the discharge air temperature in the RTU was controlled according to the outdoor air temperature, energy consumption of the RTU was reduced by 6% in cooling operations and by 18% in heating operation. As a result, energy consumption of the VRF system was reduced by more than that of the RTU by 55% approximately.« less

Stirling Air Conditioner for Compact Cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2010-09-01

BEETIT Project: Infinia is developing a compact air conditioner that uses an unconventional high efficient Stirling cycle system (vs. conventional vapor compression systems) to produce cool air that is energy efficient and does not rely on polluting refrigerants. The Stirling cycle system is a type of air conditioning system that uses a motor with a piston to remove heat to the outside atmosphere using a gas refrigerant. To date, Stirling systems have been expensive and have not had the right kind of heat exchanger to help cool air efficiently. Infinia is using chip cooling technology from the computer industry tomore » make improvements to the heat exchanger and improve system performance. Infinia’s air conditioner uses helium gas as refrigerant, an environmentally benign gas that does not react with other chemicals and does not burn. Infinia’s improvements to the Stirling cycle system will enable the cost-effective mass production of high-efficiency air conditioners that use no polluting refrigerants.« less

Transient states of air parameters after a stoppage and re-start of the main fan / Stany przejściowe parametrów powietrza po postoju i załączeniu wentylatora głównego

NASA Astrophysics Data System (ADS)

Wasilewski, Stanisław

2012-12-01

A stoppage of the main ventilation fan constitutes a disturbance of ventilation conditions of a deepmine and its effects can cause serious hazards by generating transient states of air and gas flow. Main ventilation fans are the basic deep-mine facilities; therefore, under mining regulations it is only allowed to stop them with the consent and under the conditions specified by the mine maintenance manager. The stoppage of the main ventilation fan may be accompanied by transient air parameters, including the air pressure and flow patterns. There is even the likelihood of reversing the direction of air flow, which, in case of methane mines, can pose a major hazard, particularly in sections of the mine with fire fields or large goaf areas. At the same time, stoppages of deep-mine main ventilation fans create interesting research conditions, which if conducted under the supervision of the monitoring systems, can provide much information about the transient processes of pressure, air and gas flow in underground workings. This article is a discussion of air parameter observations in mine workings made as part of such experiments. It also presents the procedure of the experiments, conducted in three mines. They involved the observation of transient processes of mine air parameters, and most interestingly, the recording of pressure and air and gas flow in the workings of the mine ventilation networks by mine monitoring systems and using specialist recording instruments. In mining practice, both in Poland and elsewhere, software tools and computer modelling methods are used to try and reproduce the conditions prior to and during disasters based on the existing network model and monitoring system data. The use of these tools to simulate the alternatives of combating and liquidation of the gas-fire hazard after its occurrence is an important issue. Measurement data collected during the experiments provides interesting research material for the verification and validation of the software tools used for the simulation of processes occurring in deep-mine ventilation systems.

Drying Characteristics and Water-soluble Polysaccharides Evaluation of Kidney Shape Ganoderma lucidum Drying in Air Circulation System

NASA Astrophysics Data System (ADS)

Prasetyo, D. J.; Jatmiko, T. H.; Poeloengasih, C. D.; Kismurtono, M.

2017-12-01

In this project, drying kinetic of kidney shape Ganoderma lucidum fruiting body in air circulation system was studied. The drying experiments were conducted at 40, 50 and 60°C with air flow rate of 1.3 ms-1. Samples were weighted periodically until no change in sample weight was recorded, and then the samples were analyzed for its moisture content. Four different thin-layer mathematical models (Newton, Page, Two-term, Midilli) were used and compare to evaluate the drying curves of kidney shape G. lucidum. The water-soluble polysaccharides were evaluated in order to find the best drying temperature condition. The results indicates that Midilli model was the fittest model to describe the characteristic of kidney shape G. lucidum in the air circulation drying system and temperature of 50°C was the best drying condition to get highest value of water-soluble polysaccharides.

Considerations to Prevent Growth and Spread of Legionella in HVAC Systems.

ERIC Educational Resources Information Center

Coleman, Jeff

1998-01-01

Discusses the threat posed by the Legionnaire's Disease bacterium and the germ's ability to thrive in heating, ventilating, and air conditioning (HVAC) systems, especially in standing water. Describes ways to minimize disease risk through HVAC system design (such as locating cooling towers away from air intakes) and ways to maintain a clean…

14 CFR Appendix E to Part 43 - Altimeter System Test and Inspection

Code of Federal Regulations, 2011 CFR

2011-01-01

... made that would affect the relationship between air pressure in the static pressure system and true ambient static air pressure for any flight condition. (b) Altimeter: (1) Test by an appropriately rated... inspections required by § 91.411 shall comply with the following: (a) Static pressure system: (1) Ensure...

Coordinated Parallel Runway Approaches

NASA Technical Reports Server (NTRS)

Koczo, Steve

1996-01-01

The current air traffic environment in airport terminal areas experiences substantial delays when weather conditions deteriorate to Instrument Meteorological Conditions (IMC). Expected future increases in air traffic will put additional pressures on the National Airspace System (NAS) and will further compound the high costs associated with airport delays. To address this problem, NASA has embarked on a program to address Terminal Area Productivity (TAP). The goals of the TAP program are to provide increased efficiencies in air traffic during the approach, landing, and surface operations in low-visibility conditions. The ultimate goal is to achieve efficiencies of terminal area flight operations commensurate with Visual Meteorological Conditions (VMC) at current or improved levels of safety.

Preliminary study of TEC application in cooling system

NASA Astrophysics Data System (ADS)

Sulaiman, A. C.; Amin, N. A. M.; Saidon, M. S.; Majid, M. S. A.; Rahman, M. T. A.; Kazim, M. N. F. M.

2017-10-01

Integration of thermoelectric cooling (TEC) within a space cooling system in the lecturer room is studied. The studied area (air conditioned surrounding) is encapsulated with wall, floor, roof, and glass window. TEC module is placed on the glass window. The prototype of the studied compartment is designed using cabin container. The type and number of TEC module are studied and the effects on the cooling performance are analyzed as it is assumed to be tested within an air conditioned lecturer room. The experimental and mathematical modeling of the cooling system developed. It is expected that the mathematical modeling derived from this study will be used to estimate the use of the number of TEC module to be integrated with air conditioner unit where possible.

Air Sample Conditioner Helps the Waste Treatment Plant Meet Emissions Standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

Glissmeyer, John A.; Flaherty, Julia E.; Pekour, Mikhail S.

2014-12-02

The air in three of the Hanford Site Waste Treatment and Immobilization Plant (WTP) melter off-gas discharge stacks will be hot and humid after passing through the train of emission abatement equipment. The off-gas temperature and humidity levels will be incompatible with the airborne emissions monitoring equipment required for this type of stack. To facilitate sampling from these facilities, an air sample conditioner system will be installed to introduce cool, dry air into the sample stream to reduce the temperature and dew point. This will avoid thermal damage to the instrumentation and problematic condensation. The complete sample transport system mustmore » also deliver at least 50% of the particles in the sample airstream to the sample collection and on-line analysis equipment. The primary components of the sample conditioning system were tested in a laboratory setting. The sample conditioner itself is based on a commercially-available porous tube filter design. It consists of a porous sintered metal tube inside a coaxial metal jacket. The hot gas sample stream passes axially through the porous tube, and the dry, cool air is injected into the jacket and through the porous wall of the inner tube, creating an effective sample diluter. The dilution and sample air mix along the entire length of the porous tube, thereby simultaneously reducing the dew point and temperature of the mixed sample stream. Furthermore, because the dilution air enters through the porous tube wall, the sample stream does not come in contact with the porous wall and particle deposition is reduced in this part of the sampling system. Tests were performed with an environmental chamber to supply air with the temperature and humidity needed to simulate the off-gas conditions. Air from the chamber was passed through the conditioning system to test its ability to reduce the temperature and dew point of the sample stream. To measure particle deposition, oil droplets in the range of 9 to 11 micrometer aerodynamic diameter were injected into the environmental chamber and drawn through the conditioning system, which included a filter to capture droplets that passed through the conditioner. The droplets were tagged with a fluorescent dye which allowed quantification of droplet deposition on each component of the system. The tests demonstrated the required reductions in temperature and moisture, with no condensation forming when heat tracing was added on the upstream end of the sample conditioner. Additionally, tests indicated that the system, operating at several flow rates and in both vertical and horizontal orientations, delivers nearly all of the sampled particles for analysis. Typical aerosol penetration values were between 98 and 99%. PNNL, Bechtel National Inc., and the instrument vendor are working to implement the sample conditioner into the air monitoring systems used for the melter off-gas exhaust streams. Similar technology may be useful for processes in other facilities with air exhaust streams with elevated temperature and/or humidity.« less

Solar heating system at Quitman County Bank, Marks, Mississippi

NASA Technical Reports Server (NTRS)

1980-01-01

Information on the Solar Energy Heating System installed in a single story wood frame, cedar exterior, sloped roof building is presented. The system has on-site temperature and power measurements readouts. The 468 square feet of Solaron air flat plate collectors provide for 2,000 square feet of space heating, an estimated 60 percent of the heating load. Solar heated air is distributed to the 235 cubic foot rock storage box or to the load (space heating) by a 960 cubic feet per minute air handler unit. A 7.5 ton Carrier air-to-air heat pump with 15 kilowatts of electric booster strips serve as a back-up (auxiliary) to the solar system. Motorized dampers control the direction of airflow and back draft dampers prevent thermal siphoning of conditioned air.

Investigation of air cleaning system response to accident conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrae, R.W.; Bolstad, J.W.; Foster, R.D.

1980-01-01

Air cleaning system response to the stress of accident conditions are being investigated. A program overview and hghlight recent results of our investigation are presented. The program includes both analytical and experimental investigations. Computer codes for predicting effects of tornados, explosions, fires, and material transport are described. The test facilities used to obtain supportive experimental data to define structural integrity and confinement effectiveness of ventilation system components are described. Examples of experimental results for code verification, blower response to tornado transients, and filter response to tornado and explosion transients are reported.

Waking the sleeping giant: Introducing new heat exchanger technology into the residential air-conditioning marketplace

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapp, T.; Voss, M.; Stephens, C.

1998-07-01

The Air Conditioning Industry has made tremendous strides in improvements to the energy efficiency and reliability of its product offerings over the past 40 years. These improvement can be attributed to enhancements of components, optimization of the energy cycle, and modernized and refined manufacturing techniques. During this same period, energy consumption for space cooling has grown significantly. In January of 1992, the minimum efficiency requirement for central air conditioning equipment was raised to 10 SEER. This efficiency level is likely to increase further under the auspices of the National Appliance Energy Conservation Act (NAECA). A new type of heat exchangermore » was developed for air conditioning equipment by Modine Manufacturing Company in the early 1990's. Despite significant advantages in terms of energy efficiency, dehumidification, durability, and refrigerant charge there has been little interest expressed by the air conditioning industry. A cooperative effort between Modine, various utilities, and several state energy offices has been organized to test and demonstrate the viability of this heat exchanger design throughout the nation. This paper will review the fundamentals of heat exchanger design and document this simple, yet novel technology. These experiences involving equipment retrofits have been documented with respect to the performance potential of air conditioning system constructed with PF{trademark} Heat Exchangers (generically referred to as microchannel heat exchangers) from both an energy efficiency as well as a comfort perspective. The paper will also detail the current plan to introduce 16 to 24 systems into an extended field test throughout the US which commenced in the Fall of 1997.« less

Causes of Indoor Air Quality Problems in Schools: Summary of Scientific Research. Revised Edition.

ERIC Educational Resources Information Center

Bayer, Charlene W.; Crow, Sidney A.; Fischer, John

Understanding the primary causes of indoor air quality (IAQ) problems and how controllable factors--proper heating, ventilation and air-conditioning (HVAC) system design, allocation of adequate outdoor air, proper filtration, effective humidity control, and routine maintenance--can avert problems may help all building owners, operators, and…

PTR-MS assessment of photocatalytic and sorption-based purification of recirculated cabin air during simulated 7-h flights with high passenger density.

PubMed

Wisthaler, Armin; Strøm-Tejsen, Peter; Fang, Lei; Arnaud, Timothy J; Hansel, Armin; Märk, Tilmann D; Wyon, David P

2007-01-01

Four different air purification conditions were established in a simulated 3-row 21-seat section of an aircraft cabin: no air purifier; a photocatalytic oxidation unit with an adsorptive prefilter; a second photocatalytic unit with an adsorptive prefilter; and a two-stage sorption-based air filter (gas-phase absorption and adsorption). The air purifiers placed in the cabin air recirculation system were commercial prototypes developed for use in aircraft cabin systems. The four conditions were established in balanced order on 4 successive days of each of 4 successive weeks during simulated 7-h flights with 17 occupants. Proton-transfer reaction mass spectrometry was used to assess organic gas-phase pollutants and the performance of each air purifier. The concentration of most organic pollutants present in aircraft cabin air was efficiently reduced by all three units. The photocatalytic units were found to incompletely oxidize ethanol released by the wet wipes commonly supplied with airline mealsto produce unacceptably high levels of acetaldehyde and formaldehyde.

Talaromyces rubrifaciens, a new species discovered from heating, ventilation and air conditioning systems in China.

PubMed

Luo, Yi; Lu, Xiaohong; Bi, Wu; Liu, Fan; Gao, Weiwei

2016-01-01

A new Talaromyces species, T. rubrifaciens, was isolated from supply air outlets of heating, ventilation and air conditioning (HVAC) systems in three kinds of public building in Beijing and Nanjing, China. Morphologically it exhibits many characters of section Trachyspermi but is distinguished from other species of this section by restricted growth and broad and strictly biverticillate conidiophores. Phylogenetic analyses based on the internal transcribed spacer rDNA (ITS), β-tubulin (BenA), calmodulin (CaM) and RNA polymerase second largest subunit (RPB2) genes reveal that T. rubrifaciens is a distinct species in section Trachyspermi. © 2016 by The Mycological Society of America.

Integration of a photocatalytic multi-tube reactor for indoor air purification in HVAC systems: a feasibility study.

PubMed

van Walsem, Jeroen; Roegiers, Jelle; Modde, Bart; Lenaerts, Silvia; Denys, Siegfried

2018-04-24

This work is focused on an in-depth experimental characterization of multi-tube reactors for indoor air purification integrated in ventilation systems. Glass tubes were selected as an excellent photocatalyst substrate to meet the challenging requirements of the operating conditions in a ventilation system in which high flow rates are typical. Glass tubes show a low-pressure drop which reduces the energy demand of the ventilator, and additionally, they provide a large exposed surface area to allow interaction between indoor air contaminants and the photocatalyst. Furthermore, the performance of a range of P25-loaded sol-gel coatings was investigated, based on their adhesion properties and photocatalytic activities. Moreover, the UV light transmission and photocatalytic reactor performance under various operating conditions were studied. These results provide vital insights for the further development and scaling up of multi-tube reactors in ventilation systems which can provide a better comfort, improved air quality in indoor environments, and reduced human exposure to harmful pollutants.

How to be Green and Stay in the Black: Environmental Guideline Document.

DTIC Science & Technology

1997-10-01

of the studies were within the American Society of Heating, Refrigera- tion, and Air conditioning Engineers (ASHRAE) Guidelines. Polaroid plans to...Whitney, Texas Instru- ments-Defense Group, Hughes Missile Systems, Boeing Defense Systems, and General Electric Air - craft Engines . The methodology...boxes, and the need to install space air thermostats. Description For Polaroid’s needs, engineers installed inte- grated, self-contained, thermally

Primary Exhaust Cooler at the Propulsion Systems Laboratory

NASA Image and Video Library

1952-09-21

One of the two primary coolers at the Propulsion Systems Laboratory at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. Engines could be run in simulated altitude conditions inside the facility’s two 14-foot-diameter and 24-foot-long test chambers. The Propulsion Systems Laboratory was the nation’s only facility that could run large full-size engine systems in controlled altitude conditions. At the time of this photograph, construction of the facility had recently been completed. Although not a wind tunnel, the Propulsion Systems Laboratory generated high-speed airflow through the interior of the engine. The air flow was pushed through the system by large compressors, adjusted by heating or refrigerating equipment, and de-moisturized by air dryers. The exhaust system served two roles: reducing the density of the air in the test chambers to simulate high altitudes and removing hot gases exhausted by the engines being tested. It was necessary to reduce the temperature of the extremely hot engine exhaust before the air reached the exhauster equipment. As the air flow exited through exhaust section of the test chamber, it entered into the giant primary cooler seen in this photograph. Narrow fins or vanes inside the cooler were filled with water. As the air flow passed between the vanes, its heat was transferred to the cooling water. The cooling water was cycled out of the system, carrying with it much of the exhaust heat.

14 CFR 1310.4 - Offices.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Offices. 1310.4 Section 1310.4 Aeronautics and Space AIR TRANSPORTATION SYSTEM STABILIZATION AIR TRANSPORTATION STABILIZATION BOARD AIR CARRIER GUARANTEE LOAN PROGRAM ADMINISTRATIVE REGULATIONS AND AMENDMENT OR WAIVER OF A TERM OR CONDITION OF...

14 CFR 1310.20 - Amendments.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Amendments. 1310.20 Section 1310.20 Aeronautics and Space AIR TRANSPORTATION SYSTEM STABILIZATION AIR TRANSPORTATION STABILIZATION BOARD AIR CARRIER GUARANTEE LOAN PROGRAM ADMINISTRATIVE REGULATIONS AND AMENDMENT OR WAIVER OF A TERM OR CONDITION...

Liquid-Desiccant Vapor Separation Reduces the Energy Requirements of Atmospheric Moisture Harvesting.

PubMed

Gido, Ben; Friedler, Eran; Broday, David M

2016-08-02

An innovative atmospheric moisture harvesting system is proposed, where water vapor is separated from the air prior to cooling and condensation. The system was studied using a model that simulates its three interconnected cycles (air, desiccant, and water) over a range of ambient conditions, and optimal configurations are reported for different operation conditions. Model results were compared to specifications of commercial atmospheric moisture harvesting systems and found to represent saving of 5-65% of the electrical energy requirements due to the vapor separation process. We show that the liquid desiccant separation stage that is integrated into atmospheric moisture harvesting systems can work under a wide range of environmental conditions using low grade or solar heating as a supplementary energy source, and that the performance of the combined system is superior.

Study on the marine ejector refrigeration-rotary desiccant air-conditioning system

NASA Astrophysics Data System (ADS)

Zheng, C. Y.; Zheng, G. J.; Yu, W. S.; Chen, W.

2017-08-01

A newly developed ejector refrigeration-rotary desiccant air-conditioning (ERRD A/C) system is proposed to recover ship waste heat as far as possible. Its configuration is built firstly, then its advantages are analyzed, after that, with the help of psychrometric chart, some important parameters such as power consumption, steam consumption and COP of ERRD A/C system are calculated theoretically under design conditions of a real marine A/C, and comparative analysis with conventional A/C is deployed. The results show that the power consumption of ERRD A/C system is only 32.87% of conventional A/C, which meant that ERRD A/C system has potential to make full use of ship waste heat to realize energy saving and environmental protection when using green refrigerant such as water.

Hyperbaric Chamber Equipment: A Consolidated Equipment List from Selected Multiplace Hyperbaric Facilities.

DTIC Science & Technology

1983-12-01

carbon dioxide scrubbers , air conditioning, communications, lighting, and fire detecting and fire extinguishing systems. Medical support equipment was...10 14 Humidity...............................11 5. Hydrocarb on...........................11 B. Carbon Dioxide Scrubbers .....................11 C...and ancillary equipment included gas/vapor monitoring equipment, carbon dioxide scrubbers , air conditioning, communications, lighting, and fire

HPAC Info-dex 3: Locating a trade name

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-06-01

This is the 1995/1996 listing of trade names of manufacturers of products for heating, ventilation, air conditioning and refrigeration systems published by Heating, Piping, and Air Conditioning magazine. The manufacturers are listed alphabetically along with their complete addresses and telephone and FAX numbers. Some product information is included for certain manufacturers.

Effects of air velocity on laying hen production from 24 to 27 weeks under simulated evaporatively cooled conditions

USDA-ARS?s Scientific Manuscript database

Thermal conditions play a major role in production efficiency in commercial poultry production. Mitigation of thermal stress can improve productivity, but must be achieved economically. Weather and system design can limit effectiveness of evaporative cooling and increased air movement has been sho...

Non-Print Instructional Materials for the Air Conditioning and Refrigeration Maintenance Field.

ERIC Educational Resources Information Center

Golitko, Raymond L., Ed.; And Others

This catalog contains a listing of air conditioning/refrigeration maintenance audiovisual training materials from the Houston Community College System library media collection. The material is organized by subject heading. The media titles are listed in alphabetical order by title under each subject heading in the catalog. The citation for each…

The Energy Implications of Air-Side Fouling in Constant Air Volume HVAC Systems

NASA Astrophysics Data System (ADS)

Wilson, Eric J. H.

2011-12-01

This thesis examines the effect of air-side fouling on the energy consumption of constant air volume (CAV) heating, ventilating, and air conditioning (HVAC) systems in residential and small commercial buildings. There is a particular focus on evaluating the potential energy savings that may result from the remediation of such fouling from coils, filters, and other air system components. A computer model was constructed to simulate the behavior of a building and its duct system under various levels of fouling. The model was verified through laboratory and field testing and then used to run parametric simulations to examine the range of energy impacts for various climates and duct system characteristics. A sensitivity analysis was conducted to determine the impact of parameters like duct insulation, duct leakage, duct location, and duct design on savings potential. Duct system pressures, temperatures, and energy consumption for two houses were monitored for one month. The houses' duct systems, which were both in conditioned space, were given a full cleaning, and were then monitored for another month. The flow rates at the houses improved by 10% and 6%. The improvements were primarily due to installing a new filter, as both houses had only light coil fouling. The results indicate that there was negligible change in heating energy efficiency due to the system cleaning. The parametric simulation results are in agreement with the field experiment: for systems in all eight climates, with flowrates degraded by 20% or less, if ducts are located within the thermal zone, HVAC source energy savings from cleaning are negligible or even slightly negative. However, if ducts are outside the thermal zone, savings are in the 1 to 5% range. For systems with flowrates degraded by 40%, if ducts are within the thermal zone, savings from cleaning occurs only for air conditioning energy, up to 8% in climates like Miami, FL. If ducts are outside the thermal zone, savings occurs with both heating and cooling energy, and ranges from 7% in Los Angeles, CA to 13% in Fairbanks, AK. These results assume a leaky and uninsulated duct system. The potential for savings from cleaning decreases if duct insulation is in place or sealing has been performed. The potential for energy savings is directly related to the distribution system's thermal efficiency, with air conditioner performance also playing a minor role. Results for small commercial buildings with constant air volume HVAC systems and leaky and uninsulated duct systems span a wider range: from -12% in Miami, FL to 30% in Minneapolis, MN. However, for improved ducts or ducts in the conditioned space, small commercial HVAC source energy savings is always negative (down to -17%) for flowrates degradation in the 0--40% range. The sensitivity of these results to duct characteristics (location, leakage, and insulation) and the after-cleaning flowrate, as it varies from an ideal flowrate, was also evaluated. Energy savings can reach up to 80% for some scenarios where clean airflow is severely restricted down to 20% of ideal by poor duct layout or other obstructions not removable by cleaning. In addition, a simplified spreadsheet tool was developed for technicians to use in the field to estimate potential savings resulting from a system cleaning. Measuring the temperature rise across the furnace was found to give less uncertainty than measuring the pressure rise and assuming a fan curve. Despite the uncertainty, the tool can give a general idea of the range of savings possible under various conditions.

46 CFR 194.15-5 - Ventilation.

Code of Federal Regulations, 2011 CFR

2011-10-01

....15-5 Ventilation. (a) Operations, reactions or experiments which produce toxic, noxious or corrosive...) Ventilation of air conditioning systems serving the chemical laboratory shall be designed so that air cannot...

Oceanic Whitecaps and Associated, Bubble-Mediated, Air-Sea Exchange Processes

DTIC Science & Technology

1992-10-01

experiments performed in laboratory conditions using Air-Sea Exchange Monitoring System (A-SEMS). EXPERIMENTAL SET-UP In a first look, the Air-Sea Exchange...Model 225, equipped with a Model 519 plug-in module. Other complementary information on A-SEMS along with results from first tests and calibration...between 9.50C and 22.40C within the first 24 hours after transferring the water sample into laboratory conditions. The results show an enhancement of

Land Combat Systems Industry Study 2004

DTIC Science & Technology

2004-01-01

David Barnhart, Florida Air National Guard Lt Col Warren Anderson, United States Air Force Lt Col Phillip Chudoba, United States Marine Corps Mr...beginning with the current condition of GD. CURRENT CONDITION In the business world, the rearview mirror is always clearer than the windshield. Warren ... Buffett The ICAF coursework and field trips presented the study team with ample historic data for assessing the current condition of the LCS firms

Evaluation of air-liquid interface exposure systems for in vitro assessment of airborne pollutants

EPA Science Inventory

Exposure of cells to airborne pollutants at the air-liquid interface (ALI) is a more realistic approach than exposures of submerged cells. The published literature, however, describes irreproducible and/or unrealistic experimental conditions using ALI systems. We have compared fi...

Development of a solar-powered residential air conditioner. Program review

NASA Technical Reports Server (NTRS)

1975-01-01

Progress in the effort to develop a residential solar-powered air conditioning system is reported. The topics covered include the objectives, scope and status of the program. The results of state-of-art, design, and economic studies and component and system data are also presented.

Changes in airborne fungi from the outdoors to indoor air; large HVAC systems in nonproblem buildings in two different climates.

PubMed

Kemp, P C; Neumeister-Kemp, H G; Esposito, B; Lysek, G; Murray, F

2003-01-01

Little is known about the changes in occurrence and distribution of airborne fungi as they are transported in the airstream from the outdoor air through the heating, ventilation, and air conditioning (HVAC) system to the indoor air. To better understand this, airborne fungi were analyzed in the HVAC systems of two large office buildings in different climate zones. Fungal samples were taken in each of the walk-in chambers of the HVAC systems using a six-stage Andersen Sampler with malt extract agar. Results showed that fungal species changed with different locations in the HVAC systems. The outdoor air intake produced the greatest filtration effect for both the counts and species of outdoor air fungi. The colony forming unit (CFU) counts and species diversity was further reduced in the air directly after the filters. The cooling coils also had a substantial filtration effect. However, in room air the CFU counts were double and the mixture of fungal species was different from the air leaving the HVAC system at the supply air outlet in most locations. Diffusion of outdoor air fungi to the indoors did not explain the changes in the mixture of airborne fungi from the outdoor air to the indoor air, and some of the fungi present in the indoor air did not appear to be transported indoors by the HVAC systems.

Energy Performance and Optimal Control of Air-conditioned Buildings Integrated with Phase Change Materials

NASA Astrophysics Data System (ADS)

Zhu, Na

This thesis presents an overview of the previous research work on dynamic characteristics and energy performance of buildings due to the integration of PCMs. The research work on dynamic characteristics and energy performance of buildings using PCMs both with and without air-conditioning is reviewed. Since the particular interest in using PCMs for free cooling and peak load shifting, specific research efforts on both subjects are reviewed separately. A simplified physical dynamic model of building structures integrated with SSPCM (shaped-stabilized phase change material) is developed and validated in this study. The simplified physical model represents the wall by 3 resistances and 2 capacitances and the PCM layer by 4 resistances and 2 capacitances respectively while the key issue is the parameter identification of the model. This thesis also presents the studies on the thermodynamic characteristics of buildings enhanced by PCM and on the investigation of the impacts of PCM on the building cooling load and peak cooling demand at different climates and seasons as well as the optimal operation and control strategies to reduce the energy consumption and energy cost by reducing the air-conditioning energy consumption and peak load. An office building floor with typical variable air volume (VAV) air-conditioning system is used and simulated as the reference building in the comparison study. The envelopes of the studied building are further enhanced by integrating the PCM layers. The building system is tested in two selected cities of typical climates in China including Hong Kong and Beijing. The cold charge and discharge processes, the operation and control strategies of night ventilation and the air temperature set-point reset strategy for minimizing the energy consumption and electricity cost are studied. This thesis presents the simulation test platform, the test results on the cold storage and discharge processes, the air-conditioning energy consumption and demand reduction potentials in typical air-conditioning seasons in typical China cites as well as the impacts of operation and control strategies.

An expert system for the design of heating, ventilating, and air-conditioning systems

NASA Astrophysics Data System (ADS)

Camejo, Pedro Jose

1989-12-01

Expert systems are computer programs that seek to mimic human reason. An expert system shelf, a software program commonly used for developing expert systems in a relatively short time, was used to develop a prototypical expert system for the design of heating, ventilating, and air-conditioning (HVAC) systems in buildings. Because HVAC design involves several related knowledge domains, developing an expert system for HVAC design requires the integration of several smaller expert systems known as knowledge bases. A menu program and several auxiliary programs for gathering data, completing calculations, printing project reports, and passing data between the knowledge bases are needed and have been developed to join the separate knowledge bases into one simple-to-use program unit.

MODELING THE AMBIENT CONDITION EFFECTS OF AN AIR-COOLED NATURAL CIRCULATION SYSTEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Rui; Lisowski, Darius D.; Bucknor, Matthew

The Reactor Cavity Cooling System (RCCS) is a passive safety concept under consideration for the overall safety strategy of advanced reactors such as the High Temperature Gas-Cooled Reactor (HTGR). One such variant, air-cooled RCCS, uses natural convection to drive the flow of air from outside the reactor building to remove decay heat during normal operation and accident scenarios. The Natural convection Shutdown heat removal Test Facility (NSTF) at Argonne National Laboratory (“Argonne”) is a half-scale model of the primary features of one conceptual air-cooled RCCS design. The facility was constructed to carry out highly instrumented experiments to study the performancemore » of the RCCS concept for reactor decay heat removal that relies on natural convection cooling. Parallel modeling and simulation efforts were performed to support the design, operation, and analysis of the natural convection system. Throughout the testing program, strong influences of ambient conditions were observed in the experimental data when baseline tests were repeated under the same test procedures. Thus, significant analysis efforts were devoted to gaining a better understanding of these influences and the subsequent response of the NSTF to ambient conditions. It was determined that air humidity had negligible impacts on NSTF system performance and therefore did not warrant consideration in the models. However, temperature differences between the building exterior and interior air, along with the outside wind speed, were shown to be dominant factors. Combining the stack and wind effects together, an empirical model was developed based on theoretical considerations and using experimental data to correlate zero-power system flow rates with ambient meteorological conditions. Some coefficients in the model were obtained based on best fitting the experimental data. The predictive capability of the empirical model was demonstrated by applying it to the new set of experimental data. The empirical model was also implemented in the computational models of the NSTF using both RELAP5-3D and STARCCM+ codes. Accounting for the effects of ambient conditions, simulations from both codes predicted the natural circulation flow rates very well.« less

Air quality and passenger comfort in an air-conditioned bus micro-environment.

PubMed

Zhu, Xiaoxuan; Lei, Li; Wang, Xingshen; Zhang, Yinghui

2018-04-12

In this study, passenger comfort and the air pollution status of the micro-environmental conditions in an air-conditioned bus were investigated through questionnaires, field measurements, and a numerical simulation. As a subjective analysis, passengers' perceptions of indoor environmental quality and comfort levels were determined from questionnaires. As an objective analysis, a numerical simulation was conducted using a discrete phase model to determine the diffusion and distribution of pollutants, including particulate matter with a diameter < 10 μm (PM 10 ), which were verified by experimental results. The results revealed poor air quality and dissatisfactory thermal comfort conditions in Jinan's air-conditioned bus system. To solve these problems, three scenarios (schemes A, B, C) were designed to alter the ventilation parameters. According to the results of an improved simulation of these scenarios, reducing or adding air outputs would shorten the time taken to reach steady-state conditions and weaken the airflow or lower the temperature in the cabin. The airflow pathway was closely related to the layout of the air conditioning. Scheme B lowered the temperature by 0.4 K and reduced the airflow by 0.01 m/s, while scheme C reduced the volume concentration of PM 10 to 150 μg/m 3 . Changing the air supply angle could further improve the airflow and reduce the concentration of PM 10 . With regard to the perception of airflow and thermal comfort, the scheme with an airflow provided by a 60° nozzle was considered better, and the concentration of PM 10 was reduced to 130 μg/m 3 .

Preliminary design package for residential heating/cooling system: Rankine air conditioner redesign

NASA Technical Reports Server (NTRS)

1978-01-01

A summary of the preliminary redesign and development of a marketable single family heating and cooling system is presented. The interim design and schedule status of the residential (3-ton) redesign, problem areas and solutions, and the definition of plans for future design and development activities were discussed. The proposed system for a single-family residential heating and cooling system is a single-loop, solar-assisted, hydronic-to-warm-air heating subsystem with solar-assisted domestic water heating and a Rankine-driven expansion air-conditioning subsystem.

Characteristics of indoor radon and its progeny in a Japanese dwelling while using air appliances.

PubMed

Pornnumpa, C; Tokonami, S; Sorimachi, A; Kranrod, C

2015-11-01

Characteristics of radon and its progeny were investigated in different air conditions by turning four types of indoor air appliances on and off in a two-story concrete Japanese dwelling. The four appliances were air conditioner, air cleaner, gas heater and cooker hood. The measurements were done using two devices: (1) a Si-based semiconductor detector for continuous measurement of indoor radon concentration and (2) a ZnS(Ag) scintillation counting system for equilibrium-equivalent radon concentration. Throughout the entire experiment, the cooker hood was the most effective in decreasing indoor radon concentration over a long period of time and the less effective was the air conditioner, while the air cleaner and gas heater did not affect the concentration of radon. However, the results measured in each air condition will differ according to the lifestyles and activities of the inhabitants. In this study, indoor radon and its progeny in a Japanese dwelling will be characterised by the different air conditions. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Development of a solar-powered residential air conditioner

NASA Technical Reports Server (NTRS)

1975-01-01

The initial objective of the program was the optimization (in terms of cost and performance) of a Rankine cycle mechanical refrigeration system which utilizes thermal energy from a flat solar collector for air conditioning residential buildings. However, feasibility investigations of the adsorption process revealed that a dessicant-type air conditioner offers many significant advantages. As a result, limited efforts were expended toward the optimization of such a system.

Joint Service Chemical and Biological Defense Program FY 08-09 Overview

DTIC Science & Technology

2007-10-01

of human plasma-derived butyrylcholinesterase Electronmicrograph of bacillus spores adhering to cell membrane processes Jo i n t Se rv i c e ch e m i...human performance within CB-protective systems. Carbon monolith for electro-swing adsorption Bacillus globigii spores collecting on an...integrated with the ship’s heating, ventilation, and air-conditioning ( HVAC ) systems and provides a filter air supply air for overpressurization of

Impact of cool storage air-conditioning in commercial sector on power system operation in Thailand

DOE Office of Scientific and Technical Information (OSTI.GOV)

Surapong, C.; Bundit, L.

The results are presented from an investigation into the potential application for cool storage air-conditioning, and the resultant beneficial impact on power system operation in Thailand is discussed. Field assessment through interviews with decision makers in the identified customer groups produces results that show good potential for cool storage application. Results from a computer program used to calculate power production cost and other characteristics show that substantial benefits would also accrue to the generating utility.

Thermal comfort in naturally ventilated and air-conditioned buildings in humid subtropical climate zone in China

NASA Astrophysics Data System (ADS)

Yang, Wei; Zhang, Guoqiang

2008-05-01

A thermal comfort field study has been carried out in five cities in the humid subtropical climate zone in China. The survey was performed in naturally ventilated and air-conditioned buildings during the summer season in 2006. There were 229 occupants from 111 buildings who participated in this study and 229 questionnaire responses were collected. Thermal acceptability assessment reveals that the indoor environment in naturally ventilated buildings could not meet the 80% acceptability criteria prescribed by ASHRAE Standard 55, and people tended to feel more comfortable in air-conditioned buildings with the air-conditioned occupants voting with higher acceptability (89%) than the naturally ventilated occupants (58%). The neutral temperatures in naturally ventilated and air-conditioned buildings were 28.3°C and 27.7°C, respectively. The range of accepted temperature in naturally ventilated buildings (25.0˜31.6°C) was wider than that in air-conditioned buildings (25.1˜30.3°C), which suggests that occupants in naturally ventilated buildings seemed to be more tolerant of higher temperatures. Preferred temperatures were 27.9°C and 27.3°C in naturally ventilated and air-conditioned buildings, respectively, both of which were 0.4°C cooler than neutral temperatures. This result suggests that people of hot climates may use words like “slightly cool” to describe their preferred thermal state. The relationship between draught sensation and indoor air velocity at different temperature ranges indicates that indoor air velocity had a significant influence over the occupants’ comfort sensation, and air velocities required by occupants increased with the increasing of operative temperatures. Thus, an effective way of natural ventilation which can create the preferred higher air movement is called for. Finally, the indoor set-point temperature of 26°C or even higher in air-conditioned buildings was confirmed as making people comfortable, which supports the regulation in China that in public and office buildings the set-point temperature of air-conditioning system should not be lower than 26°C.

Gas-Dynamic Designing of the Exhaust System for the Air Brake

NASA Astrophysics Data System (ADS)

Novikova, Yu; Goriachkin, E.; Volkov, A.

2018-01-01

Each gas turbine engine is tested some times during the life-cycle. The test equipment includes the air brake that utilizes the power produced by the gas turbine engine. In actual conditions, the outlet pressure of the air brake does not change and is equal to atmospheric pressure. For this reason, for the air brake work it is necessary to design the special exhaust system. Mission of the exhaust system is to provide the required level of backpressure at the outlet of the air brake. The backpressure is required for the required power utilization by the air brake (the air brake operation in the required points on the performance curves). The paper is described the development of the gas dynamic canal, designing outlet guide vane and the creation of a unified exhaust system for the air brake. Using a unified exhaust system involves moving the operating point to the performance curve further away from the calculated point. However, the applying of one exhaust system instead of two will significantly reduce the cash and time costs.

Going Straight to the Source.

ERIC Educational Resources Information Center

Crawford, Gary N.

1998-01-01

Explains how a well-designed heating and air conditioning system with good facility maintenance can prevent most indoor air quality problems in schools. Stresses attention to issues of leak prevention and sanitation. (GR)

Evaluation of Passive Vents in New Construction Multifamily Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxwell, Sean; Berger, David; Zuluaga, Marc

Exhaust ventilation and corresponding outdoor air strategies are being implemented in high-performance new construction multifamily buildings to meet program or code requirements for improved indoor air quality, but a lack of clear design guidance is resulting in poor performance of these systems despite the best intentions of the programs or standards. CARB's 2014 'Evaluation of Ventilation Strategies in New Construction Multifamily Buildings' consistently demonstrated that commonly used outdoor air strategies are not performing as expected. Of the four strategies evaluated in 2014, the exhaust ventilation system that relied on outdoor air from a pressurized corridor was ruled out as amore » potential best practice due to its conflict with meeting requirements within most fire codes. Outdoor air that is ducted directly to the apartments was a strategy determined to have the highest likelihood of success, but with higher first costs and operating costs. Outdoor air through space conditioning systems was also determined to have good performance potential, with proper design and execution. The fourth strategy, passive systems, was identified as the least expensive option for providing outdoor air directly to apartments, with respect to both first costs and operating costs. However, little is known about how they actually perform in real-world conditions or how to implement them effectively. Based on the lack of data available on the performance of these low-cost systems and their frequent use in the high-performance building programs that require a provision for outdoor air, this research project sought to further evaluate the performance of passive vents.« less

Building America Case Study: Evaluation of Passive Vents in New-Construction Multifamily Buildings, New York, New York

DOE Office of Scientific and Technical Information (OSTI.GOV)

Exhaust ventilation and corresponding outdoor air strategies are being implemented in high-performance new construction multifamily buildings to meet program or code requirements for improved indoor air quality, but a lack of clear design guidance is resulting in poor performance of these systems despite the best intentions of the programs or standards. CARB's 2014 'Evaluation of Ventilation Strategies in New Construction Multifamily Buildings' consistently demonstrated that commonly used outdoor air strategies are not performing as expected. Of the four strategies evaluated in 2014, the exhaust ventilation system that relied on outdoor air from a pressurized corridor was ruled out as amore » potential best practice due to its conflict with meeting requirements within most fire codes. Outdoor air that is ducted directly to the apartments was a strategy determined to have the highest likelihood of success, but with higher first costs and operating costs. Outdoor air through space conditioning systems was also determined to have good performance potential, with proper design and execution. The fourth strategy, passive systems, was identified as the least expensive option for providing outdoor air directly to apartments, with respect to both first costs and operating costs. However, little is known about how they actually perform in real-world conditions or how to implement them effectively. Based on the lack of data available on the performance of these low-cost systems and their frequent use in the high-performance building programs that require a provision for outdoor air, this research project sought to further evaluate the performance of passive vents.« less

Solar-powered air-conditioning

NASA Technical Reports Server (NTRS)

Clark, D. C.; Rousseau, J.

1977-01-01

Report focuses on recent study on development of solar-powered residential air conditioners and is based on selected literature through 1975. Its purposes are to characterize thermal and mechanical systems that might be useful in development of Rankine-cycle approach to solar cooling and assessment of a Lithium Bromide/Water absorption cycle system.

Terminal Air Flow Planning

NASA Technical Reports Server (NTRS)

Denery, Dallas G.; Erzberger, Heinz; Edwards, Thomas A. (Technical Monitor)

1998-01-01

The Center TRACON Automation System (CTAS) will be the basis for air traffic planning and control in the terminal area. The system accepts arriving traffic within an extended terminal area and optimizes the flow based on current traffic and airport conditions. The operational use of CTAS will be presented together with results from current operations.

Training for a Place in the Sun.

ERIC Educational Resources Information Center

Fillippini, W. L.

1979-01-01

To train sheet metal workers in energy conservation technology, the National Training Fund (NTF) of the Sheet Metal and Air Conditioning Industry collaborated with universities in developing their apprenticeship curricula on solar-powered environmental systems, a solar air system training film, and NTF instructor training courses and workshops.…

40 CFR 86.1868-12 - CO2 credits for improving the efficiency of air conditioning systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., engine displacement, transmission class and configuration, interior volume, climate control system type... Creditvalue (g/mi) Reduced reheat, with externally-controlled, variable-displacement compressor (e.g. a compressor that controls displacement based on temperature setpoint and/or cooling demand of the air...

Fact Sheet: Protection of the Stratospheric Ozone: New Substitute in the Motor Vehicle Air Conditioning Sector under the Significant New Alternatives Policy (SNAP) Program

EPA Pesticide Factsheets

Under the Significant New Alternatives Policy (SNAP) program, EPA is listing HFO-1234yf as an acceptable substitute for ozone depleting substances (ODS) in motor vehicle air conditioning (MVAC) systems in new cars and other light duty-vehicles and is speci

Heating, Air Conditioning and Refrigeration Curriculum Guide. Michigan Trade and Industrial Education.

ERIC Educational Resources Information Center

Michigan State Univ., East Lansing. Coll. of Agriculture and Natural Resources Education Inst.

This task-based curriculum guide for heating, air conditioning, and refrigeration is intended to help the teacher develop a classroom management system where students learn by doing. Introductory materials include a Dictionary of Occupational Titles job code and title sheet, a career ladder, a matrix relating duty/task numbers to job titles, and a…

Motor Transportation Technology: Automechanics. [Air Conditioning.] Block IX. A-IX.

ERIC Educational Resources Information Center

Texas A and M Univ., College Station. Vocational Instructional Services.

This packet contains 13 teacher lesson plans with related student information, job sheets, and task sheets for a block of instruction on motor vehicle refrigeration (air conditioning) systems in a course on auto mechanics. Lesson plans, which are either informational or manipulative in format, take the teacher step-by-step through each lesson.…

Cost-effective retrofit technology for reducing peak power demand in small and medium commercial buildings

DOE PAGES

Nutaro, James J.; Fugate, David L.; Kuruganti, Teja; ...

2015-05-27

We describe a cost-effective retrofit technology that uses collective control of multiple rooftop air conditioning units to reduce the peak power consumption of small and medium commercial buildings. The proposed control uses a model of the building and air conditioning units to select an operating schedule for the air conditioning units that maintains a temperature set point subject to a constraint on the number of units that may operate simultaneously. A prototype of this new control system was built and deployed in a large gymnasium to coordinate four rooftop air conditioning units. Based on data collected while operating this prototype,more » we estimate that the cost savings achieved by reducing peak power consumption is sufficient to repay the cost of the prototype within a year.« less

The Integrated Air Transportation System Evaluation Tool

NASA Technical Reports Server (NTRS)

Wingrove, Earl R., III; Hees, Jing; Villani, James A.; Yackovetsky, Robert E. (Technical Monitor)

2002-01-01

Throughout U.S. history, our nation has generally enjoyed exceptional economic growth, driven in part by transportation advancements. Looking forward 25 years, when the national highway and skyway systems are saturated, the nation faces new challenges in creating transportation-driven economic growth and wealth. To meet the national requirement for an improved air traffic management system, NASA developed the goal of tripling throughput over the next 20 years, in all weather conditions while maintaining safety. Analysis of the throughput goal has primarily focused on major airline operations, primarily through the hub and spoke system.However, many suggested concepts to increase throughput may operate outside the hub and spoke system. Examples of such concepts include the Small Aircraft Transportation System, civil tiltrotor, and improved rotorcraft. Proper assessment of the potential contribution of these technologies to the domestic air transportation system requires a modeling capability that includes the country's numerous smaller airports, acting as a fundamental component of the National Air space System, and the demand for such concepts and technologies. Under this task for NASA, the Logistics Management Institute developed higher fidelity demand models that capture the interdependence of short-haul air travel with other transportation modes and explicitly consider the costs of commercial air and other transport modes. To accomplish this work, we generated forecasts of the distribution of general aviation based aircraft and GA itinerant operations at each of nearly 3.000 airport based on changes in economic conditions and demographic trends. We also built modules that estimate the demand for travel by different modes, particularly auto, commercial air, and GA. We examined GA demand from two perspectives: top-down and bottom-up, described in detail.

Feasibility of CO/sub 2/ monitoring to assess air quality in mines using diesel equipment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, J.H. Jr.

1987-01-01

The methodology includes: (1) establishing pollutant to CO/sub 2/ ratios for in-service equipment, (2) estimating pollutant concentrations from the ratios and in-mine CO/sub 2/ measurements, and (3) using an air quality index to combine the pollutants into a single number, which indicates the health hazard associated with the pollutants. For the methodology to be valid, the pollutant to CO/sub 2/ ratios must remain constant if engine operating conditions do not significantly change. However, due to the complex dynamics of the fuel injection system, the fuel-air combustion process, and the engine speed-load governing system, the pollutant to CO/sub 2/ ratios maymore » vary during repetitive, but transient engine speed-and-load operation. These transient effects were investigated. In addition, the influence of changing engine conditions due to engine maladjustment, and a practical means to evaluate engine condition were investigated to advance the methodology. The laboratory investigation determined that CO/sub 2/ is an effective indicator of engine exhaust pollutants. It was shown that the exhaust concentrations of carbon monoxide, carbon dioxide, oxides of nitrogen, hydrocarbons, and particulate matter do not significantly vary among repetitive, but transient engine speed-and-load duty cycles typical of in-service equipment. Based on an air quality index and threshold limit values, particulate matter exhibited the greatest adverse effect on air quality. Particulate mass was separated into volatile (organic soluble fraction) and nonvolatile (insoluble carbon fraction) components. Due to particulate concentrations, the engine operating conditions of overfueling and advanced injector timing had greater adverse effects on air quality than the conditions of retarded injector timing, intake air restriction, and Federal certification specifications.« less

Bond strength of poly(methyl methacrylate) denture base material to cast titanium and cobalt-chromium alloy.

PubMed

Matsuda, Yasuhiro; Yanagida, Hiroaki; Ide, Takako; Matsumura, Hideo; Tanoue, Naomi

2010-06-01

The shear bond strength of an auto-polymerizing poly(methyl methacrylate) denture base resin material to cast titanium and cobalt-chromium alloy treated with six conditioning methods was investigated. Disk specimens (10 mm in diameter and 2.5 mm in thickness) were cast from pure titanium and cobalt-chromium alloy. The specimens were wet ground to a final surface finish of 600 grit, air dried, and treated with the following bonding systems: 1) air abraded with 50-70-microm-grain alumina (SAN); 2) air abraded with 50-70-microm-grain alumina + conditioned with Alloy Primer (ALP); 3) air abraded with 50-70-microm-grain alumina + conditioned with AZ Primer (AZP); 4) air abraded with 50-70-microm-grain alumina + conditioned with Estenia Opaque Primer (EOP); 5) air abraded with 50-70-microm-grain alumina + conditioned with Metal Link Primer (MLP), and 6) treated with ROCATEC system (ROC). A denture base material (Palapress Vario) was then applied to each metal specimen. Shear bond strengths were determined before and after 10,000 thermocycles. The strengths decreased after thermocycling in all combinations. Among the treatment methods assessed, groups 2 and 4 showed significantly (p < 0.05) enhanced shear bond strengths for both metals. In group 4, the strength in MPa (n = 7) after thermocycling for cobalt-chromium alloy was 38.3, which was statistically (p < 0.05) higher than that for cast titanium (34.7). Air abrasion followed by the application of two primers containing a hydrophobic phosphate monomer (MDP) effectively improved the strength of the bond of denture base material to cast titanium and cobalt-chromium alloy.

The passive control of air pollution exposure in Dublin, Ireland: a combined measurement and modelling case study.

PubMed

Gallagher, J; Gill, L W; McNabola, A

2013-08-01

This study investigates the potential real world application of passive control systems to reduce personal pollutant exposure in an urban street canyon in Dublin, Ireland. The implementation of parked cars and/or low boundary walls as a passive control system has been shown to minimise personal exposure to pollutants on footpaths in previous investigations. However, previous research has been limited to generic numerical modelling studies. This study combines real-time traffic data, meteorological conditions and pollution concentrations, in a real world urban street canyon before and after the implementation of a passive control system. Using a combination of field measurements and numerical modelling this study assessed the potential impact of passive controls on personal exposure to nitric oxide (NO) concentrations in the street canyon in winter conditions. A calibrated numerical model of the urban street canyon was developed, taking into account the variability in traffic and meteorological conditions. The modelling system combined the computational fluid dynamic (CFD) simulations and a semi-empirical equation, and demonstrated a good agreement with measured field data collected in the street canyon. The results indicated that lane distribution, fleet composition and vehicular turbulence all affected pollutant dispersion, in addition to the canyon geometry and local meteorological conditions. The introduction of passive controls displayed mixed results for improvements in air quality on the footpaths for different wind and traffic conditions. Parked cars demonstrated the most comprehensive passive control system with average improvements in air quality of up to 15% on the footpaths. This study highlights the potential of passive controls in a real street canyon to increase dispersion and improve air quality at street level. Copyright © 2013 Elsevier B.V. All rights reserved.

Indoor air quality and the law in Singapore.

PubMed

Chan, P

1999-12-01

With the greater use of air-conditioned offices in Singapore, achieving good indoor air quality has become an important issue. The laws that impose duties upon designers and contractors with respect to the design and construction of air-conditioning and mechanical ventilation (ACMV) systems are set out in the Building Control Regulations and the Singapore Standard Code of Practice for Mechanical Ventilation and Air-conditioning in Buildings (hereinafter "SS CP 13:1980"). ACMV maintenance is governed by the Environmental Public Health Act, the Building and Common Property (Maintenance and Management) Act, and the Land Titles (Strata) Act, as well as by lease or tenancy agreements. Designers, contractors, developers, building owners and management corporations may also be liable to the workers, occupants and other premises users for indoor air quality (IAQ)-related injuries under the general principles of contract and tort. Recently, the Guidelines for Good Indoor Air Quality in Office Premises was issued by the Ministry of Environment to complement SS CP 13:1980 toward improving the indoor air quality of air-conditioned office premises. Although the Guidelines have no statutory effect, they may be adopted as contractual requirements in construction, lease and maintenance contracts. They may also be used to determine the relevant standard of duty of care required to discharge tortious liability. This paper looks at the existing laws and rules affecting the design, construction and maintenance of air-conditioned offices in light of Part III of the Ministry's Guidelines.

Stay away from asthma triggers

MedlinePlus

... cleaner with a HEPA (high-efficiency particulate arrestor) filter. Replace wall-to-wall carpet with wood or ... a central air conditioning system, use a HEPA filter to remove pet allergens from indoor air. Use ...

Liquid over-feeding air conditioning system and method

DOEpatents

Mei, Viung C.; Chen, Fang C.

1993-01-01

A refrigeration air conditioning system utilizing a liquid over-feeding operation is described. A liquid refrigerant accumulator-heat exchanger is placed in the system to provide a heat exchange relationship between hot liquid refrigerant discharged from condenser and a relatively cool mixture of liquid and vaporous refrigerant discharged from the evaporator. This heat exchange relationship substantially sub-cools the hot liquid refrigerant which undergoes little or no evaporation across the expansion device and provides a liquid over-feeding operation through the evaporator for effectively using 100 percent of evaporator for cooling purposes and for providing the aforementioned mixture of liquid and vaporous refrigerant.

Relevance of air conditioning for 222Radon concentration in shops of the Savona Province, Italy.

PubMed

Panatto, Donatella; Ferrari, Paola; Lai, Piero; Gallelli, Giovanni

2006-02-15

Radon (222Rn) concentration was evaluated in shops of the Savona Province, Italy, between summer 2002 and winter 2002-2003. The main characteristics of each shops were recorded through a questionnaire investigating the ventilation rate and factors related to 222Rn precursors in the soil and the construction materials. The main variables that were related to radon concentration were the following: age of the building, level of the shop above ground, season of the year, wind exposure, active windows, and type of heating system. Shops equipped with individual air heating/conditioning systems exhibited radon concentrations that were three times higher than those of shops heated by centralized furnaces. Our data indicate that the level of pollution in the shops was of medium level, with an expected low impact on the salespersons' health. Only in wintertime, the action level of 200 Bq m(-3) for the confined environment was reached in 10 shops equipped with individual air heating/conditioning systems.

Characterization of a starch based desiccant wheel dehumidifier

NASA Astrophysics Data System (ADS)

Beery, Kyle Edward

Starch, cellulose, and hemicellulose have an affinity for water, and adsorb water vapor from air. Materials made from combinations of these biobased sugar polymers also have been found to possess adsorptive properties. An interesting possible application of these starch-based adsorbents is the desiccant wheel dehumidifier. The desiccant wheel dehumidifier is used in conjunction with a standard air conditioning system. In this process, ambient air is passed through a stationary section while a wheel packed with desiccant rotates through that section. The desiccant adsorbs humidity (latent load) from the air, and the air conditioning system then cools the air (sensible load). Several starch based adsorbents were developed and tested for adsorptive capacity in a new high throughput screening system. The best formulations from the high throughput screening system, also taking into account economic considerations and structural integrity, were considered for use in the desiccant wheel dehumidifier. A suitable adsorbent was chosen and formulated into a matrix structure for the desiccant wheel system. A prototype desiccant wheel system was constructed and the performance was investigated under varying regeneration temperatures and rotation speeds. The results from the experiments showed that the starch based desiccant wheel dehumidification system does transfer moisture from the inlet process stream to the outlet regeneration stream. The DESSIM model was modified for the starch based adsorbent and compared to the experimental results. Also, the results when the wheel parameters were varied were compared to the predicted results from the model. The results given by the starch based desiccant wheel system show the desired proof of concept.

DOE Office of Scientific and Technical Information (OSTI.GOV)

This study tests the performance of a variable airflow small-diameter duct heating, ventilation, and air conditioning (HVAC) system in a new construction unoccupied low-load test house in Pittsburgh, Pennsylvania. The duct system was installed entirely in conditioned space and was operated from the winter through summer seasons. Measurements were collected on the in-room temperatures and energy consumed by the air handler and heat pump unit. Operation modes with three different volumes of airflow were compared to determine the ideal airflow scenario that maximizes room-to-room thermal uniformity while minimizing fan energy consumption. Black felt infrared imagery was used as a measuremore » of diffuser throw and in-room air mixing. Measured results indicate the small-diameter, high velocity airflow system can provide comfort under some conditions. Solar heat gains resulted in southern rooms drifting beyond acceptable temperature limits. Insufficient airflow to some bedrooms also resulted in periods of potential discomfort. Homebuilders or HVAC contractors can use these results to assess whether this space conditioning strategy is an attractive alternative to a traditional duct system. The team performed a cost analysis of two duct system configurations: (1) a conventional diameter and velocity duct system, and (2) the small-diameter duct system. This work applies to both new and retrofit homes that have achieved a low heating and cooling density either by energy conservation or by operation in a mild climate with few heating or cooling degree days. Guidance is provided on cost trade-offs between the conventional duct system and the small-diameter duct system.« less

Challenges in Commercial Buildings | Buildings | NREL

Science.gov Websites

generation prototype desiccant-enhanced evaporative air conditioner that links to a fact sheet about NREL's Energy-Saving Technology for Air Conditioning Cuts Peak Power Loads Without Using Harmful Refrigerants . Photo of a SolarWall solar ventilation air preheating system on the AVUM helicopter maintenance hangar

24 CFR 3280.702 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-04-01

... (in the case of a heat pump) heating system which includes the refrigerant pump (compressor) and the external heat exchanger. Air conditioning evaporator section means a heat exchanger used to cool or (in the case of a heat pump) heat air for use in comfort cooling (or heating) the living space. Air...

24 CFR 3280.702 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-04-01

... (in the case of a heat pump) heating system which includes the refrigerant pump (compressor) and the external heat exchanger. Air conditioning evaporator section means a heat exchanger used to cool or (in the case of a heat pump) heat air for use in comfort cooling (or heating) the living space. Air...

24 CFR 3280.702 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-04-01

... means that portion of a refrigerated air cooling or (in the case of a heat pump) heating system which includes the refrigerant pump (compressor) and the external heat exchanger. Air conditioning evaporator section means a heat exchanger used to cool or (in the case of a heat pump) heat air for use in comfort...

Drop transfer between superhydrophobic wells using air logic control.

PubMed

Vuong, Thach; Cheong, Brandon Huey-Ping; Huynh, So Hung; Muradoglu, Murat; Liew, Oi Wah; Ng, Tuck Wah

2015-02-21

Superhydrophobic surfaces aid biochemical analysis by limiting sample loss. A system based on wells here tolerated tilting up to 20° and allowed air logic transfer with evidence of mixing. Conditions for intact transfer on 15 to 60 μL drops using compressed air pressure operation were also mapped.

Clearing the Air about IAQ.

ERIC Educational Resources Information Center

Seyffer, Charles

1999-01-01

Discusses how to spot indoor air quality (IAQ) problems in schools and possible actions to take to eliminate them. Highlights the types of pollutants that contribute to IAQ deterioration and the physical symptoms commonly associated with them, and suggests ways of addressing older heating, ventilation, and air conditioning systems to improve air…

High Temperatures Health Monitoring of the Condensed Water Height in Steam Pipe Systems

NASA Technical Reports Server (NTRS)

Lih, Shyh-Shiuh; Bar-Cohen, Yoseph; Lee, Hyeong Jae; Badescu, Mircea; Bao, Xiaoqi; Sherrit, Stewart; Takano, Nobuyuki; Ostlund, Patrick; Blosiu, Julian

2013-01-01

Ultrasonic probes were designed, fabricated and tested for high temperature health monitoring system. The goal of this work was to develop the health monitoring system that can determine the height level of the condensed water through the pipe wall at high temperature up to 250 deg while accounting for the effects of surface perturbation. Among different ultrasonic probe designs, 2.25 MHz probes with air backed configuration provide satisfactory results in terms of sensitivity, receiving reflections from the target through the pipe wall. A series of tests were performed using the air-backed probes under irregular conditions, such as surface perturbation and surface disturbance at elevated temperature, to qualify the developed ultrasonic system. The results demonstrate that the fabricated air-backed probes combined with advanced signal processing techniques offer the capability of health monitoring of steam pipe under various operating conditions.

Assessment of Natural Ventilation System for a Typical Residential House in Poland

NASA Astrophysics Data System (ADS)

Antczak-Jarząbska, Romana; Krzaczek, Marek

2016-09-01

The paper presents the research results of field measurements campaign of natural ventilation performance and effectiveness in a residential building. The building is located in the microclimate whose parameters differ significantly in relation to a representative weather station. The measurement system recorded climate parameters and the physical variables characterizing the air flow in the rooms within 14 days of the winter season. The measurement results showed that in spite of proper design and construction of the ventilation system, unfavorable microclimatic conditions that differed from the predicted ones caused significant reduction in the efficiency of the ventilation system. Also, during some time periods, external climate conditions caused an opposite air flow direction in the vent inlets and outlets, leading to a significant deterioration of air quality and thermal comfort measured by CO2 concentration and PMV index in a residential area.

Development of a solar-powered residential air conditioner: System optimization preliminary specification

NASA Technical Reports Server (NTRS)

Rousseau, J.; Hwang, K. C.

1975-01-01

Investigations aimed at the optimization of a baseline Rankine cycle solar powered air conditioner and the development of a preliminary system specification were conducted. Efforts encompassed the following: (1) investigations of the use of recuperators/regenerators to enhance the performance of the baseline system, (2) development of an off-design computer program for system performance prediction, (3) optimization of the turbocompressor design to cover a broad range of conditions and permit operation at low heat source water temperatures, (4) generation of parametric data describing system performance (COP and capacity), (5) development and evaluation of candidate system augmentation concepts and selection of the optimum approach, (6) generation of auxiliary power requirement data, (7) development of a complete solar collector-thermal storage-air conditioner computer program, (8) evaluation of the baseline Rankine air conditioner over a five day period simulating the NASA solar house operation, and (9) evaluation of the air conditioner as a heat pump.

CFD simulation research on residential indoor air quality.

PubMed

Yang, Li; Ye, Miao; He, Bao-Jie

2014-02-15

Nowadays people are excessively depending on air conditioning to create a comfortable indoor environment, but it could cause some health problems in a long run. In this paper, wind velocity field, temperature field and air age field in a bedroom with wall-hanging air conditioning running in summer are analyzed by CFD numerical simulation technology. The results show that wall-hanging air conditioning system can undertake indoor heat load and conduct good indoor thermal comfort. In terms of wind velocity, air speed in activity area where people sit and stand is moderate, most of which cannot feel wind flow and meet the summer indoor wind comfort requirement. However, for air quality, there are local areas without ventilation and toxic gases not discharged in time. Therefore it is necessary to take effective measures to improve air quality. Compared with the traditional measurement method, CFD software has many advantages in simulating indoor environment, so it is hopeful for humans to create a more comfortable, healthy living environment by CFD in the future. Copyright © 2013 Elsevier B.V. All rights reserved.

Characteristic Boundary Conditions for ARO-1

DTIC Science & Technology

1983-05-01

I As shown in Fig. 3, the point designated II is the interior point that was used to define the barred coordinate system , evaluated at time t=. All...L. Jacocks Calspan Field Services, Inc. May 1983 Final Report for Period October 1981 - September 1982 r Approved for public release; destribut ...on unlimited I ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AIR FORCE STATION, TENNESSEE AIR FORCE SYSTEMS COMMAND UNITED STATES AIR FORCE N O T I

Air removal device. [life support systems

NASA Technical Reports Server (NTRS)

Booth, F. W.; Bruce, R. A.

1981-01-01

The disclosure concerns a device suitable for removing air from water under both zero and one 'g' gravity conditions. The device is comprised of a pair of spaced membranes on being hydrophobic and the other being hydrophilic. The air-water mixture is introduced into the space therebetween, and the selective action of the membranes yields removal of the air from the water.

Comparison of freezing control strategies for residential air-to-air heat recovery ventilators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, E.G.; Bradley, L.C.; Chant, R.E.

1989-01-01

A comparison of the energy performance of defrost and frost control strategies for residential air-to-air heat recovery ventilators (HRV) has been carried out by using computer simulations for various climatic conditions. This paper discusses the results and conclusions from the comparisons and their implications for the heat recovery ventilator manufacturers and system designers.

Short-term airing by natural ventilation - implication on IAQ and thermal comfort.

PubMed

Heiselberg, P; Perino, M

2010-04-01

The need to improve the energy efficiency of buildings requires new and more efficient ventilation systems. It has been demonstrated that innovative operating concepts that make use of natural ventilation seem to be more appreciated by occupants. Among the available ventilation strategies that are currently available, buoyancy driven, single-sided natural ventilation has proved to be very effective and can provide high air change rates for temperature and Indoor Air Quality (IAQ) control. However, to promote a wider distribution of these systems an improvement in the knowledge of their working principles is necessary. The present study analyses and presents the results of an experimental evaluation of airing performance in terms of ventilation characteristics, IAQ and thermal comfort. It includes investigations of the consequences of opening time, opening frequency, opening area and expected airflow rate, ventilation efficiency, thermal comfort and dynamic temperature conditions. A suitable laboratory test rig was developed to perform extensive experimental analyses of the phenomenon under controlled and repeatable conditions. The results showed that short-term window airing is very effective and can provide both acceptable IAQ and thermal comfort conditions in buildings. Practical Implications This study gives the necessary background and in-depth knowledge of the performance of window airing by single-sided natural ventilation necessary for the development of control strategies for window airing (length of opening period and opening frequency) for optimum IAQ and thermal comfort in naturally ventilated buildings.

Assessment of microbiological indoor air quality in an Italian office building equipped with an HVAC system.

PubMed

Bonetta, Sa; Bonetta, Si; Mosso, S; Sampò, S; Carraro, E

2010-02-01

The purpose of this study was to evaluate the level and composition of bacteria and fungi in the indoor air of an Italian office building equipped with a heating, ventilation and air conditioning (HVAC) system. Airborne bacteria and fungi were collected in three open-space offices during different seasons. The microbial levels in the outdoor air, supply air diffusers, fan coil air flow and air treatment unit humidification water tank were used to evaluate the influence of the HVAC system on indoor air quality (IAQ). A medium-low level of bacterial contamination (50-500 CFU/m(3)) was found in indoor air. Staphylococcus and Micrococcus were the most commonly found genera, probably due to human presence. A high fungal concentration was measured due to a flood that occurred during the winter. The indoor seasonal distribution of fungal genera was related to the fungal outdoor distribution. Significant seasonal and daily variation in airborne microorganisms was found, underlining a relationship with the frequency of HVAC system switching on/off. The results of this monitoring highlight the role of the HVAC system on IAQ and could be useful to better characterise bacterial and fungal population in the indoor air of office buildings.

Expert system for the design of heating, ventilating, and air-conditioning systems. Master's thesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Camejo, P.J.

1989-12-01

Expert systems are computer programs that seek to mimic human reason. An expert system shelf, a software program commonly used for developing expert systems in a relatively short time, was used to develop a prototypical expert system for the design of heating, ventilating, and air-conditioning (HVAC) systems in buildings. Because HVAC design involves several related knowledge domains, developing an expert system for HVAC design requires the integration of several smaller expert systems known as knowledge bases. A menu program and several auxiliary programs for gathering data, completing calculations, printing project reports, and passing data between the knowledge bases are neededmore » and have been developed to join the separate knowledge bases into one simple-to-use program unit.« less

Air conditioned suit

NASA Technical Reports Server (NTRS)

Carl, G. R. (Inventor)

1973-01-01

An environmentally controlled suit is described consisting of an airtight outergarment attached by an airtight bellows to the wall of a sterile chamber, an undergarment providing for circulation of air near the skin of the wearer, and a circulation system comprised of air supply and distribution to the extremities of the undegarment and central collection and exhaust of air from the midsection of the undergarment. A workman wearing the undergarment and attached circulation system enters the outer garment through a tunnel in the chamber wall and the attached bellows to work in the chamber without any danger of spreading bacteria.

Investigation of the Intake of a Stationary Gas Turbine to Prevent Ice Formation

NASA Astrophysics Data System (ADS)

Tramposch, Andreas; Molnár, Vojtech; Ridzoň, František

2011-12-01

Repeated emergency shutdowns of a stationary gas turbine under conditions of sub-freezing temperatures and moist air have led to the suspicion that ice formation in the intake channel and compressor may be a contributing factor. To understand the reason, why the installed ice protection system is not effective, a numerical investigation of the intake channel with the installed hot air ice protection system has been performed. It is shown that mixing of hot air with cold outside air is incomplete, explaining the ice accretion.

Effect of timed secondary-air injection on automotive emissions

NASA Technical Reports Server (NTRS)

Coffin, K. P.

1973-01-01

A single cylinder of an automotive V-8 engine was fitted with an electronically timed system for the pulsed injection of secondary air. A straight-tube exhaust minimized any mixing other than that produced by secondary-air pulsing. The device was operated over a range of engine loads and speeds. Effects attributable to secondary-air pulsing were found, but emission levels were generally no better than using the engine's own injection system. Under nontypical fast-idle, no-load conditions, emission levels were reduced by roughly a factor of 2.

WASTE HANDLING BUILDING VENTILATION SYSTEM DESCRIPTION DOCUMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

P.A. Kumar

2000-06-21

The Waste Handling Building Ventilation System provides heating, ventilation, and air conditioning (HVAC) for the contaminated, potentially contaminated, and uncontaminated areas of the Monitored Geologic Repository's (MGR) Waste Handling Building (WHB). In the uncontaminated areas, the non-confinement area ventilation system maintains the proper environmental conditions for equipment operation and personnel comfort. In the contaminated and potentially contaminated areas, in addition to maintaining the proper environmental conditions for equipment operation and personnel comfort, the contamination confinement area ventilation system directs potentially contaminated air away from personnel in the WHB and confines the contamination within high-efficiency particulate air (HEPA) filtration units. Themore » contamination confinement areas ventilation system creates airflow paths and pressure zones to minimize the potential for spreading contamination within the building. The contamination confinement ventilation system also protects the environment and the public by limiting airborne releases of radioactive or other hazardous contaminants from the WHB. The Waste Handling Building Ventilation System is designed to perform its safety functions under accident conditions and other Design Basis Events (DBEs) (such as earthquakes, tornadoes, fires, and loss of the primary electric power). Additional system design features (such as compartmentalization with independent subsystems) limit the potential for cross-contamination within the WHB. The system provides status of important system parameters and equipment operation, and provides audible and/or visual indication of off-normal conditions and equipment failures. The Waste Handling Building Ventilation System confines the radioactive and hazardous material within the building such that the release rates comply with regulatory limits. The system design, operations, and maintenance activities incorporate ALARA (as low as is reasonably achievable) principles to maintain personnel radiation doses to all occupational workers below regulatory limits and as low as is reasonably achievable. The Waste Handling Building Ventilation System interfaces with the Waste Handling Building System by being located within the WHB and by maintaining specific pressures, temperatures, and humidity within the building. The system also depends on the WHB for water supply. The system interfaces with the Site Radiological Monitoring System for continuous monitoring of the exhaust air; the Waste Handling Building Fire Protection System for detection of fire and smoke; the Waste Handling Building Electrical System for normal, emergency, and standby power; and the Monitored Geologic Repository Operations Monitoring and Control System for monitoring and control of the system.« less

Using real-time syndromic surveillance systems to help explore the acute impact of the air pollution incident of March/April 2014 in England.

PubMed

Smith, Gillian E; Bawa, Zharain; Macklin, Yolande; Morbey, Roger; Dobney, Alec; Vardoulakis, Sotiris; Elliot, Alex J

2015-01-01

During March and early April 2014 there was widespread poor air quality across the United Kingdom. Public Health England used existing syndromic surveillance systems to monitor community health during the period. Short lived statistically significant rises in a variety of respiratory conditions, including asthma and wheeze, were detected. This incident has demonstrated the value of real-time syndromic surveillance systems, during an air pollution episode, for helping to explore the impact of poor air quality on community health in real-time. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

An Investigation of the Icing and Heated-air De-icing Characteristics of the R-2600-13 Induction System

NASA Technical Reports Server (NTRS)

Chapman, Gilbert E.

1946-01-01

A laboratory investigation was made on a Holley 1685-HB carburetor mounted on an R-2600-13 supercharger assembly to determine the icing characteristics and the heated-air de-icing requirements of this portion of the B-25D airplane induction system. Icing has been found to be most prevalent at relatively small throttle openings and, consequently, all runs were made at simulated 60-percent normal rated power condition. Icing characteristics were determined during a series of 15-minute runs over a range of inlet-air conditions. For the de-icing investigation severe impact ice was allowed to form in the induction system and the time required for the recovery of 95 percent of the maximum possible air flow at the original throttle setting was then determined for a range of wet-bulb temperatures. Results of these runs showed that ice on the walls of the carburetor adapter and on the rim of the impeller-shroud portion of the supercharger diffuser plate did not affect engine operation at 60-percent normal rated power. Ice that adversely affected the air flow and the fuel-air ratio was formed only on the central web of the carburetor and then only when the inlet air was saturated or contained free moisture in excess of saturation. No serious ice formations were observed at inlet-air temperatures above 66 0 F or with an inlet-air enthalpy greater than 34 Btu per pound. The maximum temperature at. which any trace of icing could be detected was 1110 F with a relative humidity of approximately 28 percent, The air-flow recovery time for emergency de-icing was 0.3 minute for.an enthalpy of 35 Btu per pound or wet-bulb temperature of 68 0 F. Further increase in enthalpy and wet-bulb temperature above these values resulted in very slight improvement in recovery time. The fuel-air ratio restored by a 5-Minute application of heated air was approximately 7 percent less than the initial value for cold-air conditions.

Implementation of a WRF-CMAQ Air Quality Modeling System in Bogotá, Colombia

NASA Astrophysics Data System (ADS)

Nedbor-Gross, R.; Henderson, B. H.; Pachon, J. E.; Davis, J. R.; Baublitz, C. B.; Rincón, A.

2014-12-01

Due to a continuous economic growth Bogotá, Colombia has experienced air pollution issues in recent years. The local environmental authority has implemented several strategies to curb air pollution that have resulted in the decrease of PM10 concentrations since 2010. However, more activities are necessary in order to meet international air quality standards in the city. The University of Florida Air Quality and Climate group is collaborating with the Universidad de La Salle to prioritize regulatory strategies for Bogotá using air pollution simulations. To simulate pollution, we developed a modeling platform that combines the Weather Research and Forecasting Model (WRF), local emissions, and the Community Multi-scale Air Quality model (CMAQ). This platform is the first of its kind to be implemented in the megacity of Bogota, Colombia. The presentation will discuss development and evaluation of the air quality modeling system, highlight initial results characterizing photochemical conditions in Bogotá, and characterize air pollution under proposed regulatory strategies. The WRF model has been configured and applied to Bogotá, which resides in a tropical climate with complex mountainous topography. Developing the configuration included incorporation of local topography and land-use data, a physics sensitivity analysis, review, and systematic evaluation. The threshold, however, was set based on synthesis of model performance under less mountainous conditions. We will evaluate the impact that differences in autocorrelation contribute to the non-ideal performance. Air pollution predictions are currently under way. CMAQ has been configured with WRF meteorology, global boundary conditions from GEOS-Chem, and a locally produced emission inventory. Preliminary results from simulations show promising performance of CMAQ in Bogota. Anticipated results include a systematic performance evaluation of ozone and PM10, characterization of photochemical sensitivity, and air quality predictions under proposed regulatory scenarios.

Air conditioning a vaccine laboratory. [Connaught Medical Research Laboratory, Toronto, Canada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross J.

1976-05-01

In 1974, the new Bacterial Vaccine Building of Connaught Medical Research Laboratories, Toronto, Canada, was opened to produce such vaccines as pertussis, typhoid, paratyphoids, and cholera and such toxoids as staphylococcus, diphtheria, and tetanus. It also produces other medicinal products. The layout of the complex and the air conditioning system necessary in all zones are described and schematically shown. (MCW)

Refrigeration and Air Conditioning Mechanic: Apprenticeship Course Outline. Apprenticeship and Industry Training. 1411.2

ERIC Educational Resources Information Center

Alberta Advanced Education and Technology, 2011

2011-01-01

The graduate of the Refrigeration and Air Conditioning Mechanic apprenticeship training is a journeyman who will: (1) supervise, train and coach apprentices; (2) use and maintain hand and power tools to the standards of competency and safety required in the trade; (3) have a thorough knowledge of the principle components of refrigeration systems,…

Competency Index for Air Conditioning and Refrigeration Programs in Missouri. A Crosswalk of Selected Instructional Materials against Missouri's Competency Profile.

ERIC Educational Resources Information Center

Missouri Univ., Columbia. Instructional Materials Lab.

This index was developed to help air conditioning and refrigeration instructors in Missouri use existing instructional materials and keep track of student progress on the VAMS system. The list was compiled by a committee of instructors who selected appropriate references and identified areas that pertained to Missouri competencies. The index lists…

Articulated, Performance-Based Instruction Objectives Guide for Air Conditioning, Refrigeration, and Heating (Environmental Control System Installer/Servicer). Edition I.

ERIC Educational Resources Information Center

Henderson, William Edward, Jr., Ed.

This articulation guide contains 17 units of instruction for the first year of a two-year vocational program designed to prepare the high school graduate to install, maintain, and repair various types of residential and commercial heating, air conditioning, and refrigeration equipment. The units are to introduce the student to fundamental theories…

Effects of suspension of air-conditioning on airtight-type racks.

PubMed

Kanzaki, M; Fujieda, M; Furukawa, T

2001-10-01

Although isolation racks are superior to open-type racks in terms of securing breeding conditions for laboratory animals, the contingency-proofing capability of the former has yet to be determined. Therefore, from the view of risk management, we studied the environmental change in isolation racks by forcibly suspending ventilation and air-conditioning and confirming the maximal time length for complete recovery to the original condition after restarting their operations. The isolation racks were placed in a room that was equipped with an independent air-conditioning system. When the inside condition of the racks reached 22-24 degrees C and 59-64% of relative humidity, the air-conditioning and ventilation were forcibly suspended and the subsequent temperature, relative humidity, ammonium and CO2 concentrations in the racks were measured over time. We found that after suspending the air-conditioning and ventilation, it took 40-60 min for temperature, and about 10 min for relative humidity to exceed the maximum values (temperature and relative humidity) referred to in the Showa 58 Nenban Guideline Jikken Doubutsu Shisetsu no Kenchiku oyobi Setsubi (Guidelines of buildings and facilities for experimental animals in Japan; Year 1983 edition). After 17 hr 25 min of the suspension of air-conditioning and ventilation, two rats were found dead. Then, the air-conditioning and ventilation were restarted. It took about 2 hr for temperature, and 50 min for relative humidity to regain the guideline values. The ammonium concentration stayed within the guideline value with a maximum concentration of 2 ppm in the experimental period, whereas the CO2 concentration was found to exceed 9% at the time of animal death.

Field Commissioning of a Daylight-Dimming Lighting System.

ERIC Educational Resources Information Center

Floyd, David B.; Parker, Danny S.

A Florida elementary school cafeteria, retrofitted with a fluorescent lighting system that dims in response to available daylight, was evaluated through real time measurement of lighting and air conditioning power, work plane illumination, and interior/exterior site conditions. The new system produced a 27 percent reduction in lighting power due…

Aspergillus prevalence in air conditioning filters from vehicles: taxis for patient transportation, forklifts, and personal vehicles.

PubMed

Viegas, Carla; Moreira, Ricardo; Faria, Tiago; Caetano, Liliana Aranha; Carolino, Elisabete; Gomes, Anita Quintal; Viegas, Susana

2018-05-04

The frequency and importance of Aspergillus infections is increasing worldwide. This study aimed to assess the occupational exposure of forklifts and taxi drivers to Aspergillus spp. Nineteen filters from air conditioning system of taxis, 17 from forklifts and 37 from personal vehicles were assessed. Filters extract were streaked onto MEA, DG18 and in azole-supplemented media. Real-time quantitative PCR amplification of selected Aspergillus species-complex was also performed. Forklifts filter samples presented higher median values. Aspergillus section Nigri was the most observed in forklifts filters in MEA (28.2%) and in azole-supplemented media. DNA from Aspergillus sections Fumigati and Versicolores was successfully amplified by qPCR. This study enlightens the added value of using filters from the air conditioning system to assess Aspergillus spp. occupational exposure. Aspergillus azole resistance screening should be included in future occupational exposure assessments.

Remote Sensing of Battlefield Weather Conditions Using Unmanned Air Vehicles

DTIC Science & Technology

1982-09-01

November 1981 - 1 September 1982 September 1982 DTIC S•’ ELECTE FEB 1 o1983 AIR FORCE GEMPHYSICS LABORATORY j AIR FORCE SYSTEMS COMMAND UNITED STATES AIR...1982 AIR VEHICLES 6. PERFORMING ORG, REPORT NUMBER 7. AUTHOR(@) 8 a. CONTRACT OR GRANT NUMBER(a) Maynard L. Hill Contributors: E. Lucero, J . Rowland...of MQM107A BWOFS Mission ........... . . . 27 Table 3 Roller-coaster Mission Analysis Summary . . . . . . . . . . . . . 30 J Table 4 Metfly Mission

Evaluation of malodor for automobile air conditioner evaporator by using laboratory-scale test cooling bench.

PubMed

Kim, Kyung Hwan; Kim, Sun Hwa; Jung, Young Rim; Kim, Man Goo

2008-09-12

As one of the measures to improve the environment in an automobile, malodor caused by the automobile air-conditioning system evaporator was evaluated and analyzed using laboratory-scale test cooling bench. The odor was simulated with an evaporator test cooling bench equipped with an airflow controller, air temperature and relative humidity controller. To simulate the same odor characteristics that occur from automobiles, one previously used automobile air conditioner evaporator associated with unpleasant odors was selected. The odor was evaluated by trained panels and collected with aluminum polyester bags. Collected samples were analyzed by thermal desorption into a cryotrap and subsequent gas chromatographic separation, followed by simultaneous olfactometry, flame ionization detector and identified by atomic emission detection and mass spectrometry. Compounds such as alcohols, aldehydes, and organic acids were identified as responsible odor-active compounds. Gas chromatography/flame ionization detection/olfactometry combined sensory method with instrumental analysis was very effective as an odor evaluation method in an automobile air-conditioning system evaporator.

Glacioclimatological study of Perennial Ice in the Fuji Ice Cave, Japan. Part I. Seasonal variation and mechanism of maintenance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ohata, Tetsuo; Furukawa, Teruo; Higuchi, Keiji

1994-08-01

Perennial cave ice in a cave located at Mt. Fuji in central Japan was studied to investigate the basic characteristics and the cause for existence of such ice under warm ground-level climate considering the ice cave as a thermal and hydrological system. Fuji Ice Cave is a lava tube cave 150 m in length with a collapsed part at the entrance. Measurements from 1984 to 1986 showed that the surface-level change of floor ice occurred due to freezing and melting at the surface and that melting at the bottom of the ice was negligible. The annual amplitude of change inmore » surface level was larger near the entrance. Meterological data showed that the cold air inflow to the cave was strong in winter, but in summer the cave was maintained near 0[degrees]C with only weak inflow of warm air. The predominant wind system was from the entrance to the interior in both winter and summer, but the spatial scale of the wind system was different. Heat budget consideration of the cave showed that the largest component was the strong inflow of subzero dry air mass in winter. Cooling in winter was compensated for by summer inflow of warm air, heat transport from the surrounding ground layer, and loss of sensible heat due to cooling of the cave for the observed year. Strong inflow of cold air and weak inflow of warm air, which is extremely low compared to the ground level air, seemed to be the most important condition. Thus the thermal condition of the cave is quasi-balanced at the presence condition below 0[degrees]C with ice. It can be said that the interrelated result of the climatological and special structural conditions makes this cave very cold, and allows perennial ice to exist in the cave. Other climatological factors such as precipitation seem to be minor factors. 17 refs., 3 figs., 3 tabs.« less

[The health status of children from industrial towns due ambient air pollution].

PubMed

Meĭbaliev, M T

2008-01-01

The author's observations suggest that hygienic monitoring in an industrial city should be made in two areas: 1) ambient air quality and 2) human health. Ambient air quality should be monitored in each town in accordance with an individual program, by taking into account the volume and nature of hazardous substances from the stationary stations, as well as weather conditions, the planning system of residential areas, and the layout of an industrial zone. Monitoring of the population's health in the industrial town should be adapted to the forms and conditions of ambient air quality monitoring in order to reveal environmental pollution-induced changes.

Engine starting and stopping

NASA Astrophysics Data System (ADS)

Curnock, Barry

Different starter systems for jet engines are discussed: electric, cartridge, iso-propyl-nitrate, air, gas turbine, and hydraulic. The fuel system, ignition system, air flow control system, and actual starting mechanism of an air starter motor system are considered. The variation of engine parameters throughout a typical starting sequence are described, with reference to examples for an RB211-535 engine. Physical constraints on engine starting are considered: rotating stall, light up, the window between hang and stall, hang, compressor stall, and the effects of ambient conditions. The following are also discussed: contractual and airworthiness requirements; windmilling; inflight relighting; afterburning light up; combustion stability; and broken shafts. Graphics illustrating the above are presented.

Vanadium Inhalation in a Mouse Model for the Understanding of Air-Suspended Particle Systemic Repercussion

PubMed Central

Fortoul, T. I.; Rodriguez-Lara, V.; Gonzalez-Villalva, A.; Rojas-Lemus, M.; Cano-Gutierrez, G.; Ustarroz-Cano, M.; Colin-Barenque, L.; Montaño, L. F.; García-Pelez, I.; Bizarro-Nevares, P.; Lopez-Valdez, N.; Falcon-Rodriguez, C. I.; Jimenez-Martínez, R. S.; Ruiz-Guerrero, M. L.; López-Zepeda, L. S.; Morales-Rivero, A.; Muñiz-Rivera-Cambas, A.

2011-01-01

There is an increased concern about the health effects that air-suspended particles have on human health which have been dissected in animal models. Using CD-1 mouse, we explore the effects that vanadium inhalation produce in different tissues and organs. Our findings support the systemic effects of air pollution. In this paper, we describe our findings in different organs in our conditions and contrast our results with the literature. PMID:21716674

Design and experimental investigation of an ejector in an air-conditioning and refrigeration system

DOE Office of Scientific and Technical Information (OSTI.GOV)

AL-Khalidy, N.; Zayonia, A.

1995-12-31

This paper discusses the conservation of energy in a refrigerant ejector refrigerating machine using heat driven from the concentrator collectors. The working refrigerant was R-113. The design of an ejector operating in an air-conditioning and refrigerating system with a low thermal source (70 C to 100 C) is presented. The influence of three major parameters--boiler, condenser, and evaporator temperature--on ejector efficiency is discussed. Experimental results show that the condenser temperature is the major influence at a low evaporator temperature. The maximum ejector efficiency was 31%.

Next Generation Refrigeration Lubricants for Low Global Warming Potential/Low Ozone Depleting Refrigeration and Air Conditioning Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hessell, Edward Thomas

The goal of this project is to develop and test new synthetic lubricants that possess high compatibility with new low ozone depleting (LOD) and low global warming potential (LGWP) refrigerants and offer improved lubricity and wear protection over current lubricant technologies. The improved compatibility of the lubricants with the refrigerants, along with improved lubricating properties, will resulted in lower energy consumption and longer service life of the refrigeration systems used in residential, commercial and industrial heating, ventilating and air-conditioning (HVAC) and refrigeration equipment.

Instrumentation, control and data management for the MIST (Modular Integrated Utility System) Facility

NASA Technical Reports Server (NTRS)

Celino, V. A.

1977-01-01

An appendix providing the technical data required for computerized control and/or monitoring of selected MIST subsystems is presented. Specific computerized functions to be performed are as follows: (1) Control of the MIST heating load simulator and monitoring of the diesel engine generators' cooling system; (2) Control of the MIST heating load simulator and MIST heating subsystem including the heating load simulator; and (3) Control of the MIST air conditioning load simulator subsystem and the MIST air conditioning subsystem, including cold thermal storage and condenser water flows.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poerschke, Andrew; Rudd, Armin

This report investigates the feasibility of using a home-run manifold small-diameter duct system to provide space-conditioning air to individual thermal zones in a low-load home. This compact layout allows duct systems to easily be brought within conditioned space via interior partition walls. Centrally locating the air handling unit in the house significantly reduces duct lengths. The plenum box is designed so that each connected duct receives a similar amount of airflow—regardless of its position on the box. Furthermore, within a reasonable set of length restrictions each duct continues to receive similar airflow.

Computer package for the design and optimization of absorption air conditioning system operated by solar energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sofrata, H.; Khoshaim, B.; Megahed, M.

1980-12-01

In this paper a computer package for the design and optimization of the simple Li-Br absorption air conditioning system, operated by solar energy, is developed in order to study its performance. This was necessary, as a first step, before carrying out any computations regarding the dual system (1-3). The computer package has the facilities of examining any parameter which may control the system; namely generator, evaporator, condenser, absorber temperatures and pumping factor. The output may be tabulated and also fed to the graph plotter. The flow chart of the programme is explained in an easy way and a typical examplemore » is included.« less

The MIST /MIUS Integration and Subsystems Test/ laboratory - A testbed for the MIUS /Modular Integrated Utility System/ program

NASA Technical Reports Server (NTRS)

Beckham, W. S., Jr.; Keune, F. A.

1974-01-01

The MIUS (Modular Integrated Utility System) concept is to be an energy-conserving, economically feasible, integrated community utility system to provide five necessary services: electricity generation, space heating and air conditioning, solid waste processing, liquid waste processing, and residential water purification. The MIST (MIUS Integration and Subsystem Test) integrated system testbed constructed at the Johnson Space Center in Houston includes subsystems for power generation, heating, ventilation, and air conditioning (HVAC), wastewater management, solid waste management, and control and monitoring. The key design issues under study include thermal integration and distribution techniques, thermal storage, integration of subsystems controls and displays, incinerator performance, effluent characteristics, and odor control.

Measured Performance of a Varied Airflow Small-Diameter Duct System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poerschke, Andrew

2017-03-01

This study tests the performance of a variable airflow small-diameter duct heating, ventilation, and air conditioning (HVAC) system in a new construction unoccupied low-load test house in Pittsburgh, Pennsylvania. The duct system was installed entirely in conditioned space and was operated from the winter through summer seasons. Measurements were collected on the in-room temperatures and energy consumed by the air handler and heat pump unit. Operation modes with three different volumes of airflow were compared to determine the ideal airflow scenario that maximizes room-to-room thermal uniformity while minimizing fan energy consumption. Black felt infrared imagery was used as a measuremore » of diffuser throw and in-room air mixing. Measured results indicate the small-diameter, high velocity airflow system can provide comfort under some conditions. Solar heat gains resulted in southern rooms drifting beyond acceptable temperature limits. Insufficient airflow to some bedrooms also resulted in periods of potential discomfort. Homebuilders or HVAC contractors can use these results to assess whether this space conditioning strategy is an attractive alternative to a traditional duct system. The team performed a cost analysis of two duct system configurations: (1) a conventional diameter and velocity duct system, and (2) the small-diameter duct system. This work applies to both new and retrofit homes that have achieved a low heating and cooling density either by energy conservation or by operation in a mild climate with few heating or cooling degree days. Guidance is provided on cost trade-offs between the conventional duct system and the small-diameter duct system.« less

Measured Performance of a Varied Airflow Small-Diameter Duct System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poerschke, Andrew

This study tests the performance of a variable airflow small-diameter duct heating, ventilation, and air conditioning (HVAC) system in a new construction unoccupied low-load test house in Pittsburgh, Pennsylvania. The duct system was installed entirely in conditioned space and was operated from the winter through summer seasons. Measurements were collected on the in-room temperatures and energy consumed by the air handler and heat pump unit. Operation modes with three different volumes of airflow were compared to determine the ideal airflow scenario that maximizes room-to-room thermal uniformity while minimizing fan energy consumption. Black felt infrared imagery was used as a measuremore » of diffuser throw and in-room air mixing. Measured results indicate the small-diameter, high velocity airflow system can provide comfort under some conditions. Solar heat gains resulted in southern rooms drifting beyond acceptable temperature limits. Insufficient airflow to some bedrooms also resulted in periods of potential discomfort. Homebuilders or HVAC contractors can use these results to assess whether this space conditioning strategy is an attractive alternative to a traditional duct system. The team performed a cost analysis of two duct system configurations: (1) a conventional diameter and velocity duct system, and (2) the small-diameter duct system. This work applies to both new and retrofit homes that have achieved a low heating and cooling density either by energy conservation or by operation in a mild climate with few heating or cooling degree days. Guidance is provided on cost trade-offs between the conventional duct system and the small-diameter duct system.« less

Building America Case Study: High-Velocity Small-Diameter Duct System, Pittsburgh, Pennsylvania

DOE Office of Scientific and Technical Information (OSTI.GOV)

A. Poerschke

This study tests the performance of a variable airflow small-diameter duct heating, ventilation, and air conditioning (HVAC) system in a new construction unoccupied low-load test house in Pittsburgh, Pennsylvania. The duct system was installed entirely in conditioned space and was operated from the winter through summer seasons. Measurements were collected on the in-room temperatures and energy consumed by the air handler and heat pump unit. Operation modes with three different volumes of airflow were compared to determine the ideal airflow scenario that maximizes room-to-room thermal uniformity while minimizing fan energy consumption. Black felt infrared imagery was used as a measuremore » of diffuser throw and in-room air mixing. Measured results indicate the small-diameter, high velocity airflow system can provide comfort under some conditions. Solar heat gains resulted in southern rooms drifting beyond acceptable temperature limits. Insufficient airflow to some bedrooms also resulted in periods of potential discomfort. Homebuilders or HVAC contractors can use these results to assess whether this space conditioning strategy is an attractive alternative to a traditional duct system. The team performed a cost analysis of two duct system configurations: (1) a conventional diameter and velocity duct system, and (2) the small-diameter duct system. This work applies to both new and retrofit homes that have achieved a low heating and cooling density either by energy conservation or by operation in a mild climate with few heating or cooling degree days. Guidance is provided on cost trade-offs between the conventional duct system and the small-diameter duct system.« less

New control design principles based on measured performance and energy analysis of HVAC (Heating, Ventilating, and Air-Conditioning) systems

NASA Astrophysics Data System (ADS)

Hittle, D. C.; Johnson, D. L.

1985-01-01

This report is one of a series on the development of heating, ventilating, and air-conditioning (HVAC) control systems that are simple, efficient, reliable, maintainable, and well-documented. This report identifies major problems associated with three currently used HVAC control systems. It also describes the development of a retrofit control system applicable to military buildings that will allow easy identification of component failures, facilitate repair, and minimize system failures. Evaluation of currently used controls showed that pneumatic temperature control equipment requires a very clean source of supply air and is also not very accurate. Pneumatic, rather than electronic, actuators should be used because they are cheaper and require less maintenance. Thermistor temperature detectors should not be used for HVAC applications because they require frequent calibration. It was found that enthalpy economy cycles cannot be used for control because the humidity sensors required for their use are prone to rapid drift, inaccurate, and hard to calibrate in the field. Performance of control systems greatly affects HVAC operating costs. Significant savings can be achieved if proportional-plus-integral control schemes are used. Use of the retrofit prototype control panel developed in this study on variable-air-volume systems should provide significant energy cost savings, improve comfort and reliability, and reduce maintenance costs.

A new device for dynamic sampling of radon in air

NASA Astrophysics Data System (ADS)

Lozano, J. C.; Escobar, V. Gómez; Tomé, F. Vera

2000-08-01

A new system is proposed for the active sampling of radon in air, based on the well-known property of activated charcoal to retain radon. Two identical carbon-activated cartridges arranged in series remove the radon from the air being sampled. The air passes first through a desiccant cell and then the carbon cartridges for short sampling times using a low-flow pump. The alpha activity for each cartridge is determined by a liquid scintillation counting system. The cartridge is placed in a holder into a vial that also contains the appropriate amount of scintillation cocktail, in a way that avoids direct contact between cocktail and charcoal. Once dynamic equilibrium between the phases has been reached, the vials can be counted. Optimum sampling conditions concerning flow rates and sampling times are determined. Using those conditions, the method was applied to environmental samples, straightforwardly providing good results for very different levels of activity.

Autoignition in a premixing-prevaporizing fuel duct using 3 different fuel injection systems at inlet air temperatures to 1250 K

NASA Technical Reports Server (NTRS)

Tacina, R. R.

1983-01-01

Conditions were determined in a continuous-flow, premixing-prevaporizing duct at which autoignition occurred. Test conditions were representative of an advanced, regenerative-cycle, automotive gas turbine. The test conditions inlet air temperatures from 600 to 1250 K (a vitiated preheater was used), pressures from 170 to 600 kPa, air velocities of 10 to 30 m/sec, equivalence ratios from 0.3 to 1.0, mixing lengths from 10 to 60 cm, and residence times of 2 to 100 ms. The fuel was diesel number 2. The duct was insulated and had an inside diameter of 12 cm. Three different fuel injection systems were used: One was a single simplex pressure atomizer, and the other two were multiple-source injectors. The data obtained with the simplex and one of the multiple-source injectors agreed satisfactorily with the references and correlated with an Arrenhius expression. The data obtained with the other multiple source injector, which used multiple cones to improve the fuel-air distribution, did not correlate well with residence time.

Performance of a convective, infrared and combined infrared- convective heated conveyor-belt dryer.

PubMed

El-Mesery, Hany S; Mwithiga, Gikuru

2015-05-01

A conveyor-belt dryer was developed using a combined infrared and hot air heating system that can be used in the drying of fruits and vegetables. The drying system having two chambers was fitted with infrared radiation heaters and through-flow hot air was provided from a convective heating system. The system was designed to operate under either infrared radiation and cold air (IR-CA) settings of 2000 W/m(2) with forced ambient air at 30 °C and air flow of 0.6 m/s or combined infrared and hot air convection (IR-HA) dryer setting with infrared intensity set at 2000 W/m(2) and hot at 60 °C being blown through the dryer at a velocity of 0.6 m/s or hot air convection (HA) at an air temperature of 60 °C and air flow velocity 0.6 m/s but without infrared heating. Apple slices dried under the different dryer settings were evaluated for quality and energy requirements. It was found that drying of apple (Golden Delicious) slices took place in the falling rate drying period and no constant rate period of drying was observed under any of the test conditions. The IR-HA setting was 57.5 and 39.1 % faster than IR-CA and HA setting, respectively. Specific energy consumption was lower and thermal efficiency was higher for the IR-HA setting when compared to both IR-CA and HA settings. The rehydration ratio, shrinkage and colour properties of apples dried under IR-HA conditions were better than for either IR-CA or HA.

Analysis of AIRS and IASI System Performance Under Clear and Cloudy Conditions

NASA Technical Reports Server (NTRS)

Aumann, Hartmut H.; Strow, L. Larrabee

2010-01-01

The radiometric and spectral system performance of space-borne infrared radiometers is generally specified and analyzed under strictly cloud-free, spatially uniform and warm conditions, with the assumption that the observed performance applies to the full dynamic range under clear and cloudy conditions and that random noise cancels for the evaluation of the radiometric accuracy. Such clear conditions are found in only one percent of the data. Ninety nine percent of the data include clouds, which produce spatially highly non-uniform scenes with 11 micrometers window brightness temperatures as low as 200K. We use AIRS and IASI radiance spectra to compare system performance under clear and a wide range of cloudy conditions. Although the two instruments are in polar orbits, with the ascending nodes separated by four hours, daily averages already reveal surprisingly similar measurements. The AIRS and IASI radiometric performance based on the mean of large numbers of observation is comparable and agrees within 200 mK over a wide range of temperatures. There are also some unexpected differences at the 200 -500 mK level, which are of significance for climate applications. The results were verified with data from July 2007 through January 2010, but many can already be gleaned from the analysis of a single day of data.

Analysis of economic and environmental benefits of a new heat pump air conditioning system with a heat recovery device

NASA Astrophysics Data System (ADS)

Li, lingxue

2017-08-01

The paper designs a new wind-water cooling and heating water conditioner system, connects cooling tower with heat recovery device, which uses cooling water to completely remove the heat that does not need heat recollection, in order to ensure that the system can work efficiently with higher performance coefficient. After the test actual engineering operation, the system’s maximum cooling coefficient of performance can reach 3.5. Its maximum comprehensive coefficient of performance can reach 6.5. After the analysis of its economic and environmental, we conclude that the new system can save 89822 kw per year. It reflects energy-saving and environmental benefits of the cold and hot water air conditioning system.

[Distribution of environmental temperature and relative humidity according to the number of conditioned air changes in laboratory animals rooms].

PubMed

Fujita, S; Obara, T; Tanaka, I; Yamauchi, C

1981-01-01

The relation of the rate of circulating air change to room temperature and relative humidity in animal quarters with a central air-conditioning system during heating and cooling seasons was investigated, with the results as follows: During the period of heating, the ambient temperature generally rose with a fall of relative humidity as the number of conditioned air changes per hour was increased. Vertical differences in temperature and humidity between levels of 0.5 and 1.5 m above the floor also diminished with increasing air change rate. This tendency was more conspicuous in small animals rooms with outer walls facing north and west. With increasing rate of air changes, the room temperature was prone to decline and the relative humidity to rise during the period of cooling. There were less vertical differences in temperature and humidity during this period. The velocity of air circulation within the animal quarters and its variations tended to increase progressively with increasing rate of ventilation, though the changes were modest.

Liquid over-feeding air conditioning system and method

DOEpatents

Mei, V.C.; Chen, F.C.

1993-09-21

A refrigeration air conditioning system utilizing a liquid over-feeding operation is described. A liquid refrigerant accumulator-heat exchanger is placed in the system to provide a heat exchange relationship between hot liquid refrigerant discharged from condenser and a relatively cool mixture of liquid and vaporous refrigerant discharged from the evaporator. This heat exchange relationship substantially sub-cools the hot liquid refrigerant which undergoes little or no evaporation across the expansion device and provides a liquid over-feeding operation through the evaporator for effectively using 100 percent of evaporator for cooling purposes and for providing the aforementioned mixture of liquid and vaporous refrigerant. 1 figure.

Effect of heating-ventilation-air conditioning system sanitation on airborne fungal populations in residential environments.

PubMed

Garrison, R A; Robertson, L D; Koehn, R D; Wynn, S R

1993-12-01

Commercial air duct sanitation services are advertised to the public as being effective in reducing indoor aeroallergen levels despite the absence of published supporting data. Eight residential heat-ventilation-air conditioning (HVAC) systems in six homes and seven HVAC systems in five homes in winter and summer, respectively, were sampled to determine fungal colony forming units (CFUs) prior to and after an HVAC sanitation procedure was performed by a local company. Two houses in which no sanitation procedure was performed served as controls in each study phase. Two sample sets were obtained at each HVAC system prior to cleaning in order to determine baseline CFU levels. The test HVAC systems were then cleaned, and the HVAC systems allowed to operate as desired by the residents. Posttreatment sampling was performed 48 hours and then weekly after cleaning for 8 weeks. The HVAC systems were analyzed by exposing sterile 2% malt extract media plates at a 90-degree angle to the air flow at the air supply and air return vents. The baseline CFUs were similar in the control and study houses. Eight weeks after sanitation, the study houses demonstrated an overall CFU reduction of 92% during winter and 84% during summer. No reduction in CFU values was observed over the 8-week study period for the houses selected as controls. Further, HVAC sanitation appeared to reduce the number of fungal colonies entering and leaving the HVAC system, suggesting that the HVAC contained a significant percentage of the total fungal load in these homes. These data suggest that HVAC sanitation may be an effective tool in reducing airborne fungal populations in residential environments.

40 CFR 86.1867-12 - CO2 credits for reducing leakage of air conditioning refrigerant.

Code of Federal Regulations, 2013 CFR

2013-07-01

... shall calculate an annual rate of refrigerant leakage from an air conditioning system in grams per year... shall be rounded to the nearest tenth of a gram per year. The procedures of SAE J2727 may be used to... be rounded to the nearest tenth of a gram per year. (b) The CO2-equivalent gram per mile leakage...

40 CFR 86.1867-12 - CO2 credits for reducing leakage of air conditioning refrigerant.

Code of Federal Regulations, 2014 CFR

2014-07-01

... annual rate of refrigerant leakage from an air conditioning system in grams per year according to the... to the nearest tenth of a gram per year. The procedures of SAE J2727 may be used to determine leakage... nearest tenth of a gram per year. (b) The CO2-equivalent gram per mile leakage reduction used to calculate...

Development of an environmental chamber for evaluating the performance of low-cost air quality sensors under controlled conditions

NASA Astrophysics Data System (ADS)

Papapostolou, Vasileios; Zhang, Hang; Feenstra, Brandon J.; Polidori, Andrea

2017-12-01

A state-of-the-art integrated chamber system has been developed for evaluating the performance of low-cost air quality sensors. The system contains two professional grade chamber enclosures. A 1.3 m3 stainless-steel outer chamber and a 0.11 m3 Teflon-coated stainless-steel inner chamber are used to create controlled aerosol and gaseous atmospheres, respectively. Both chambers are temperature and relative humidity controlled with capability to generate a wide range of environmental conditions. The system is equipped with an integrated zero-air system, an ozone and two aerosol generation systems, a dynamic dilution calibrator, certified gas cylinders, an array of Federal Reference Method (FRM), Federal Equivalent Method (FEM), and Best Available Technology (BAT) reference instruments and an automated control and sequencing software. Our experiments have demonstrated that the chamber system is capable of generating stable and reproducible aerosol and gas concentrations at low, medium, and high levels. This paper discusses the development of the chamber system along with the methods used to quantitatively evaluate sensor performance. Considering that a significant number of academic and research institutions, government agencies, public and private institutions, and individuals are becoming interested in developing and using low-cost air quality sensors, it is important to standardize the procedures used to evaluate their performance. The information discussed herein provides a roadmap for entities who are interested in characterizing air quality sensors in a rigorous, systematic and reproducible manner.

Wall System Saves Initial HVAC Costs

ERIC Educational Resources Information Center

Modern Schools, 1976

1976-01-01

The superior insulating characteristics of an exterior wall system has enabled a Massachusetts school district to realize a savings on electric heating, ventilating, and air-conditioning systems. (Author/MLF)

Testing an Algae-Based Air-Regeneration System

NASA Technical Reports Server (NTRS)

Nienow, James

1998-01-01

The potential of an air-regeneration system based on the growth of unicellular algae on the surface of porous ceramic tubes was evaluated. The system is fairly robust with respect to environmental conditions and is capable of maintaining algal cultures for up to 365 days. Under standard conditions (50-66 micro mol/sq mm s (PPF), 450 micro mol mol of CO2), mature tubes can remove CO2 at a rate of up to 90 micro mol/sq m min. Under these conditions, approximately 200 square meters of area would be required for each member of the crew. However, the rate of uptake increases with both photon flux and CO2 concentration in accordance with Michaelis-Menton dynamics. An extrapolation to conditions of saturating light and carbon dioxide indicates that the area required can be reduced by a factor of at least 2.5.

29. DETAIL OF OUTLET DUCTS FOR MST AIRCONDITIONING SYSTEM IN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. DETAIL OF OUTLET DUCTS FOR MST AIR-CONDITIONING SYSTEM IN NORTHWEST CORNER OF SLC-3W MST STATION 70.5 (LOWEST PAYLOAD SERVICE STATION). NOTE RING ATTACHMENT FOR PERSONNEL SAFETY HARNESS IN LEFT FOREGROUND. - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

Icing-Protection Requirements for Reciprocating-Engine Induction System

NASA Technical Reports Server (NTRS)

Coles, Willard D; Rollin, Vern G; Mulholland, Donald R

1950-01-01

Despite the development of relatively ice-free fuel-metering systems, the widespread use of alternate and heated-air intakes, and the use of alcohol for emergency de-icing, icing of aircraft-engine induction systems is a serious problem. Investigations have been made to study and to combat all phases of this icing problem. From these investigations, criterions for safe operation and for design of new induction systems have been established. The results were obtained from laboratory investigations of carburetor-supercharger combinations, wind-tunnel investigations of air scoops, multicylinder-engine studies, and flight investigations. Characteristics of three forms of ice, impact, throttling, and fuel evaporation were studied. The effects of several factors on the icing characteristics were also studied and included: (1) atmospheric conditions, (2) engine and air-scoop configurations, including light-airplane system, (3) type fuel used, and (4) operating variables, such as power condition, use of a manifold pressure regulator, mixture setting, carburetor heat, and water-alcohol injection. In addition, ice-detection methods were investigated and methods of preventing and removing induction-system ice were studied. Recommendations are given for design and operation with regard to induction-system design.

Navier-Stokes Simulation of Airconditioning Facility of a Large Modem Computer Room

NASA Technical Reports Server (NTRS)

2005-01-01

NASA recently assembled one of the world's fastest operational supercomputers to meet the agency's new high performance computing needs. This large-scale system, named Columbia, consists of 20 interconnected SGI Altix 512-processor systems, for a total of 10,240 Intel Itanium-2 processors. High-fidelity CFD simulations were performed for the NASA Advanced Supercomputing (NAS) computer room at Ames Research Center. The purpose of the simulations was to assess the adequacy of the existing air handling and conditioning system and make recommendations for changes in the design of the system if needed. The simulations were performed with NASA's OVERFLOW-2 CFD code which utilizes overset structured grids. A new set of boundary conditions were developed and added to the flow solver for modeling the roomls air-conditioning and proper cooling of the equipment. Boundary condition parameters for the flow solver are based on cooler CFM (flow rate) ratings and some reasonable assumptions of flow and heat transfer data for the floor and central processing units (CPU) . The geometry modeling from blue prints and grid generation were handled by the NASA Ames software package Chimera Grid Tools (CGT). This geometric model was developed as a CGT-scripted template, which can be easily modified to accommodate any changes in shape and size of the room, locations and dimensions of the CPU racks, disk racks, coolers, power distribution units, and mass-storage system. The compute nodes are grouped in pairs of racks with an aisle in the middle. High-speed connection cables connect the racks with overhead cable trays. The cool air from the cooling units is pumped into the computer room from a sub-floor through perforated floor tiles. The CPU cooling fans draw cool air from the floor tiles, which run along the outside length of each rack, and eject warm air into the center isle between the racks. This warm air is eventually drawn into the cooling units located near the walls of the room. One major concern is that the hot air ejected to the middle isle might recirculate back into the cool rack side and cause thermal short-cycling. The simulations analyzed and addressed the following important elements of the computer room: 1) High-temperature build-up in certain regions of the room; 2) Areas of low air circulation in the room; 3) Potential short-cycling of the computer rack cooling system; 4) Effectiveness of the perforated cooling floor tiles; 5) Effect of changes in various aspects of the cooling units. Detailed flow visualization is performed to show temperature distribution, air-flow streamlines and velocities in the computer room.

75 FR 22581 - Energy Conservation Program for Commercial Equipment: Decision and Order Granting a Waiver to...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-29

.... (Mitsubishi) for a similar line of commercial multi-split air-conditioning systems: Testing laboratories...-conditioning systems: (1) Testing laboratories cannot test products with so many indoor units; (2) there are too many possible combinations of indoor and outdoor unit to test. The Daikin VRV-WIII systems have...

Improving Forecast Skill by Assimilation of Quality-controlled AIRS Temperature Retrievals under Partially Cloudy Conditions

NASA Technical Reports Server (NTRS)

Reale, O.; Susskind, J.; Rosenberg, R.; Brin, E.; Riishojgaard, L.; Liu, E.; Terry, J.; Jusem, J. C.

2007-01-01

The National Aeronautics and Space Administration (NASA) Atmospheric Infrared Sounder (AIRS) on board the Aqua satellite has been long recognized as an important contributor towards the improvement of weather forecasts. At this time only a small fraction of the total data produced by AIRS is being used by operational weather systems. In fact, in addition to effects of thinning and quality control, the only AIRS data assimilated are radiance observations of channels unaffected by clouds. Observations in mid-lower tropospheric sounding AIRS channels are assimilated primarily under completely clear-sky conditions, thus imposing a very severe limitation on the horizontal distribution of the AIRS-derived information. In this work it is shown that the ability to derive accurate temperature profiles from AIRS observations in partially cloud-contaminated areas can be utilized to further improve the impact of AIRS observations in a global model and forecasting system. The analyses produced by assimilating AIRS temperature profiles obtained under partial cloud cover result in a substantially colder representation of the northern hemisphere lower midtroposphere at higher latitudes. This temperature difference has a strong impact, through hydrostatic adjustment, in the midtropospheric geopotential heights, which causes a different representation of the polar vortex especially over northeastern Siberia and Alaska. The AIRS-induced anomaly propagates through the model's dynamics producing improved 5-day forecasts.

Impact of Charge Degradation on the Life Cycle Climate Performance of a Residential Air-Conditioning System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beshr, Mohamed; Aute, Vikrant; Abdelaziz, Omar

2014-01-01

Vapor compression systems continuously leak a small fraction of their refrigerant charge to the environment, whether during operation or servicing. As a result of the slow leak rate occurring during operation, the refrigerant charge decreases until the system is serviced and recharged. This charge degradation, after a certain limit, begins to have a detrimental effect on system capacity, energy consumption, and coefficient of performance (COP). This paper presents a literature review and a summary of previous experimental work on the effect of undercharging or charge degradation of different vapor compression systems, especially those without a receiver. These systems include residentialmore » air conditioning and heat pump systems utilizing different components and refrigerants, and water chiller systems. Most of these studies show similar trends for the effect of charge degradation on system performance. However, it is found that although much experimental work exists on the effect of charge degradation on system performance, no correlation or comparison between charge degradation and system performance yet exists. Thus, based on the literature review, three different correlations that characterize the effect of charge on system capacity and energy consumption are developed for different systems as follows: one for air-conditioning systems, one for vapor compression water-to-water chiller systems, and one for heat pumps. These correlations can be implemented in vapor compression cycle simulation tools to obtain a better prediction of the system performance throughout its lifetime. In this paper, these correlations are implemented in an open source tool for life cycle climate performance (LCCP) based design of vapor compression systems. The LCCP of a residential air-source heat pump is evaluated using the tool and the effect of charge degradation on the results is studied. The heat pump is simulated using a validated component-based vapor compression system model and the LCCP results obtained using the three charge degradation correlations are compared.« less

Space Cooling in North America: Market Overview and Future Impacts

DOE PAGES

Baxter, Van D; Khowailed, Gannate; Sikes, Karen; ...

2015-01-01

The North American space cooling market, particularly in the United States, is experiencing shifts in regulatory regimes, population patterns, economic conditions, and consumer preferences-all catalyzed further by rapid technological innovation. Taken together these factors may result in a slight reduction in air conditioning shipments in the short term, however the longer term trends indicate a continuing increase in the number of air conditioning systems in the U.S. markets. These increases will be greatest in the warmer and more humid (e.g. higher load demand) regions. This will result in increasing pressure on the U.S. electricity supply system to meet the energymore » peak and consumption demands for building space cooling.« less

Low temperature air with high IAQ for dry climates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scofield, C.M.; Des Champs, N.H.

1995-01-01

This article describes how low temperature supply air and air-to-air heat exchangers can furnish 100% outdoor air with reduced peak energy demands. The use of low temperature supply air systems in arid climates greatly simplifies the air-conditioning design. Risks associated with moisture migration and sweating of duct and terminal equipment are reduced. Insulation and vapor barrier design requirements are not nearly as critical as they are in the humid, ambient conditions that exist in the eastern United States. The introduction of outdoor air to meet ASHRAE Standard 62-1989 becomes far less taxing on the mechanical cooling equipment because of themore » lower enthalpy levels of the dry western climate. Energy costs to assure indoor air quality (IAQ) are lower than for more tropical climates. In arid regions, maintaining acceptable indoor relative humidity (RH) levels becomes a major IAQ concern. For the western United States, coupling an air-to-air heat exchanger to direct (adiabatic) evaporative coolers can greatly reduce low temperature supply air refrigeration energy requirements and winter humidification costs while ensuring proper ventilation.« less

Experimental evaluation of refrigerant mass charge and ambient air temperature effects on performance of air-conditioning systems

NASA Astrophysics Data System (ADS)

Deymi-Dashtebayaz, Mahdi; Farahnak, Mehdi; Moraffa, Mojtaba; Ghalami, Arash; Mohammadi, Nima

2018-03-01

In this paper the effects of refrigerant charge amount and ambient air temperature on performance and thermodynamic condition of refrigerating cycle in the split type air-conditioner have been investigated. Optimum mass charge is the point at which the energy efficiency ratio (EER) of refrigeration cycle becomes the maximum. Experiments have been conducted over a range of refrigerant mass charge from 540 to 840 g and a range of ambient temperature from 27 to 45 °C, in a 12,000 Btu/h split air-conditioner as case study. The various parameters have been considered to evaluate the cooling rate, energy efficiency ratio (EER), mass charge effect and thermodynamic cycle of refrigeration system with R22 refrigerant gas. Results confirmed that the lack of appropriate refrigerant mass charge causes the refrigeration system not to reach its maximum cooling capacity. The highest cooling capacity achieved was 3.2 kW (11,000 Btu/h). The optimum mass charge and corresponding EER of studied system have been obtained about 640 g and 2.5, respectively. Also, it is observed that EER decreases by 30% as ambient temperature increases from 27 °C to 45 °C. By optimization of the refrigerant mass charge in refrigerating systems, about 785 GWh per year of electric energy can be saved in Iran's residential sector.

Air-breathing behavior, oxygen concentrations, and ROS defense in the swimbladders of two erythrinid fish, the facultative air-breathing jeju, and the non-air-breathing traira during normoxia, hypoxia and hyperoxia.

PubMed

Pelster, Bernd; Wood, Chris M; Jung, Ellen; Val, Adalberto L

2018-05-01

The jeju Hoplerythrinus unitaeniatus and the traira Hoplias malabaricus are two neighboring genera from the family of erythrinid fish, both possessing a two-chambered physostomous swimbladder. In the jeju the anterior section of the posterior bladder is highly vascularized, and the swimbladder is used for aerial respiration; the traira, in turn, is a water-breather that uses the swimbladder as a buoyancy organ and not for aerial oxygen uptake. Measurement of swimbladder oxygen partial pressure (PO 2 ) of fish kept at 26 °C in normoxic, hyperoxic (28-32 mg O 2 L - 1 ) or hypoxic (1-1.5 mg O 2 L - 1 ) water revealed constant values in traira swimbladder. Under normoxic conditions in the jeju swimbladder PO 2 was higher than in traira, and the PO 2 significantly increased under hyperoxic conditions, even in the absence of air breathing. In jeju, air-breathing activity increased significantly under hypoxic conditions. Hypoxic air-breathing activity was negatively correlated to swimbladder PO 2 , indicating that the swimbladder was intensely used for gas exchange under these conditions. In traira, the capacity of the ROS defense system, as assessed by measurement of activities of enzymes involved in ROS degradation and total glutathione (GSH + GSSG) concentration, was elevated after 4 h of hyperoxic and/or hypoxic exposure, although swimbladder PO 2 was not affected. In jeju, experiencing a higher variability in swimbladder PO 2 due to the air-breathing activity, only a reduced responsiveness of the ROS defense system to changing environmental PO 2 was detected.

Hydronic rooftop cooling systems

DOEpatents

Bourne, Richard C [Davis, CA; Lee, Brian Eric [Monterey, CA; Berman, Mark J [Davis, CA

2008-01-29

A roof top cooling unit has an evaporative cooling section that includes at least one evaporative module that pre-cools ventilation air and water; a condenser; a water reservoir and pump that captures and re-circulates water within the evaporative modules; a fan that exhausts air from the building and the evaporative modules and systems that refill and drain the water reservoir. The cooling unit also has a refrigerant section that includes a compressor, an expansion device, evaporator and condenser heat exchangers, and connecting refrigerant piping. Supply air components include a blower, an air filter, a cooling and/or heating coil to condition air for supply to the building, and optional dampers that, in designs that supply less than 100% outdoor air to the building, control the mixture of return and ventilation air.

10 CFR 1022.5 - Applicability.

Code of Federal Regulations, 2011 CFR

2011-01-01

...) Minor modification (e.g., upgrading lighting, heating, ventilation, and air conditioning systems....g., activities such as reroofing, plumbing repair, door and window replacement); (2) Site... water and air quality, flora and fauna abundance, and soil properties) in a floodplain or wetland...

10 CFR 1022.5 - Applicability.

Code of Federal Regulations, 2012 CFR

2012-01-01

...) Minor modification (e.g., upgrading lighting, heating, ventilation, and air conditioning systems....g., activities such as reroofing, plumbing repair, door and window replacement); (2) Site... water and air quality, flora and fauna abundance, and soil properties) in a floodplain or wetland...

10 CFR 1022.5 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-01-01

...) Minor modification (e.g., upgrading lighting, heating, ventilation, and air conditioning systems....g., activities such as reroofing, plumbing repair, door and window replacement); (2) Site... water and air quality, flora and fauna abundance, and soil properties) in a floodplain or wetland...

10 CFR 1022.5 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-01-01

...) Minor modification (e.g., upgrading lighting, heating, ventilation, and air conditioning systems....g., activities such as reroofing, plumbing repair, door and window replacement); (2) Site... water and air quality, flora and fauna abundance, and soil properties) in a floodplain or wetland...

Temperature offset control system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fried, M.

1987-07-28

This patent describes a temperature offset control system for controlling the operation of both heating and air conditioning systems simultaneously contained within the same premises each of which is set by local thermostats to operate at an appropriate temperature, the offset control system comprising: a central control station having means for presetting an offset temperature range, means for sensing the temperature at a central location, means for comparing the sensed temperature with the offset temperature range, means responsive to the comparison for producing a control signal indicative of whether the sensed temperature is within the offset temperature range or beyondmore » the offset temperature range, and means for transmitting the control signal onto the standard energy lines servicing the premises; and a receiving station respectively associated with each heating and air conditioning system, the receiving stations each comprising means for receiving the same transmitted control signal from the energy lines, and switch means for controlling the energization of the respective system in response to the received control signal. The heating systems and associated local thermostat are disabled by the control signal when the control signal originates from a sensed temperature above the lower end of the offset temperature range. The air conditioning systems and associated thermostats are disabled by the same control signal when the control signal originates from a sensed temperature below the upper end of the offset temperature range.« less

Cascade Reverse Osmosis Air Conditioning System: Cascade Reverse Osmosis and the Absorption Osmosis Cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

BEETIT Project: Battelle is developing a new air conditioning system that uses a cascade reverse osmosis (RO)-based absorption cycle. Analyses show that this new cycle can be as much as 60% more efficient than vapor compression, which is used in 90% of air conditioners. Traditional vapor-compression systems use polluting liquids for a cooling effect. Absorption cycles use benign refrigerants such as water, which is absorbed in a salt solution and pumped as liquid—replacing compression of vapor. The refrigerant is subsequently separated from absorbing salt using heat for re-use in the cooling cycle. Battelle is replacing thermal separation of refrigerant withmore » a more efficient reverse osmosis process. Research has shown that the cycle is possible, but further investment will be needed to reduce the number of cascade reverse osmosis stages and therefore cost.« less

An Intelligent Harmonic Synthesis Technique for Air-Gap Eccentricity Fault Diagnosis in Induction Motors

NASA Astrophysics Data System (ADS)

Li, De Z.; Wang, Wilson; Ismail, Fathy

2017-11-01

Induction motors (IMs) are commonly used in various industrial applications. To improve energy consumption efficiency, a reliable IM health condition monitoring system is very useful to detect IM fault at its earliest stage to prevent operation degradation, and malfunction of IMs. An intelligent harmonic synthesis technique is proposed in this work to conduct incipient air-gap eccentricity fault detection in IMs. The fault harmonic series are synthesized to enhance fault features. Fault related local spectra are processed to derive fault indicators for IM air-gap eccentricity diagnosis. The effectiveness of the proposed harmonic synthesis technique is examined experimentally by IMs with static air-gap eccentricity and dynamic air-gap eccentricity states under different load conditions. Test results show that the developed harmonic synthesis technique can extract fault features effectively for initial IM air-gap eccentricity fault detection.

An inventory of aeronautical ground research facilities. Volume 2: Air breathing engine test facilities

NASA Technical Reports Server (NTRS)

Pirrello, C. J.; Hardin, R. D.; Heckart, M. V.; Brown, K. R.

1971-01-01

The inventory covers free jet and direct connect altitude cells, sea level static thrust stands, sea level test cells with ram air, and propulsion wind tunnels. Free jet altitude cells and propulsion wind tunnels are used for evaluation of complete inlet-engine-exhaust nozzle propulsion systems under simulated flight conditions. These facilities are similar in principal of operation and differ primarily in test section concept. The propulsion wind tunnel provides a closed test section and restrains the flow around the test specimen while the free jet is allowed to expand freely. A chamber of large diameter about the free jet is provided in which desired operating pressure levels may be maintained. Sea level test cells with ram air provide controlled, conditioned air directly to the engine face for performance evaluation at low altitude flight conditions. Direct connect altitude cells provide a means of performance evaluation at simulated conditions of Mach number and altitude with air supplied to the flight altitude conditions. Sea level static thrust stands simply provide an instrumented engine mounting for measuring thrust at zero airspeed. While all of these facilities are used for integrated engine testing, a few provide engine component test capability.

Predictability Analysis of PM10 Concentrations in Budapest

NASA Astrophysics Data System (ADS)

Ferenczi, Zita

2013-04-01

Climate, weather and air quality may have harmful effects on human health and environment. Over the past few hundred years we had to face the changes in climate in parallel with the changes in air quality. These observed changes in climate, weather and air quality continuously interact with each other: pollutants are changing the climate, thus changing the weather, but climate also has impacts on air quality. The increasing number of extreme weather situations may be a result of climate change, which could create favourable conditions for rising of pollutant concentrations. Air quality in Budapest is determined by domestic and traffic emissions combined with the meteorological conditions. In some cases, the effect of long-range transport could also be essential. While the time variability of the industrial and traffic emissions is not significant, the domestic emissions increase in winter season. In recent years, PM10 episodes have caused the most critical air quality problems in Budapest, especially in winter. In Budapest, an air quality network of 11 stations detects the concentration values of different pollutants hourly. The Hungarian Meteorological Service has developed an air quality prediction model system for the area of Budapest. The system forecasts the concentration of air pollutants (PM10, NO2, SO2 and O3) for two days in advance. In this work we used meteorological parameters and PM10 data detected by the stations of the air quality network, as well as the forecasted PM10 values of the air quality prediction model system. In this work we present the evaluation of PM10 predictions in the last two years and the most important meteorological parameters affecting PM10 concentration. The results of this analysis determine the effect of the meteorological parameters and the emission of aerosol particles on the PM10 concentration values as well as the limits of this prediction system.

Development of the Dual Aerodynamic Nozzle Model for the NTF Semi-Span Model Support System

NASA Technical Reports Server (NTRS)

Jones, Greg S.; Milholen, William E., II; Goodliff, Scott L.

2011-01-01

The recent addition of a dual flow air delivery system to the NASA Langley National Transonic Facility was experimentally validated with a Dual Aerodynamic Nozzle semi-span model. This model utilized two Stratford calibration nozzles to characterize the weight flow system of the air delivery system. The weight flow boundaries for the air delivery system were identified at mildly cryogenic conditions to be 0.1 to 23 lbm/sec for the high flow leg and 0.1 to 9 lbm/sec for the low flow leg. Results from this test verified system performance and identified problems with the weight-flow metering system that required the vortex flow meters to be replaced at the end of the test.

DoD Can Save Millions by Using Energy Efficient Centralized Aircraft Support Systems.

DTIC Science & Technology

1982-05-07

recommends that the Secretary of the Air Force: -- Reevaluate the decision not to install centralized systems at tactical bases. If the systems can be...discontinue using the aircraft’s onboard auxillary power units. These units consume tremendous amounts of jet fuel in providing cabin air-conditioning...requirements. Each command has been asked to analyze its bases to determine if centralized systems should be installed. Although a final decision has not

Highly integrated system solutions for air conditioning.

PubMed

Bartz, Horst

2002-08-01

Starting with the air handling unit, new features concerning energy efficient air treatment in combination with optimisation of required space were presented. Strategic concepts for the supply of one or more operating suites with a modular based air handling system were discussed. The operating theatre ceiling itself, as a major part of the whole integrated system, is no longer a simple air outlet: additional functions have been added in so-called media-bridges, so that it has changed towards a medical apparatus serving as a daily tool for the physicians and the operating staff. Last and not least, the servicing of the whole system has become an integral part of the facility management with remote access to the main functions and controls. The results are understood to be the basis for a discussion with specialists from medical and hygienic disciplines as well as with technically orientated people representing the hospital and building-engineering.

Pilot study of high-performance air filtration for classroom applications.

PubMed

Polidori, A; Fine, P M; White, V; Kwon, P S

2013-06-01

A study was conducted to investigate the effectiveness of three air purification systems in reducing the exposure of children to air contaminants inside nine classrooms of three Southern California schools. Continuous and integrated measurements were conducted to monitor the indoor and outdoor concentrations of ultrafine particles (UFPs), fine and coarse particulate matter (PM2.5 and PM10 , respectively), black carbon (BC), and volatile organic compounds. An heating, ventilating, and air conditioning (HVAC)-based high-performance panel filter (HP-PF), a register-based air purifier (RS), and a stand-alone air cleaning system (SA) were tested alone and in different combinations for their ability to remove the monitored pollutants. The combination of a RS and a HP-PF was the most effective solution for lowering the indoor concentrations of BC, UFPs, and PM2.5 , with study average reductions between 87% and 96%. When using the HP-PF alone, reductions close to 90% were also achieved. In all cases, air quality conditions were improved substantially with respect to the corresponding baseline (preexisting) conditions. Data on the performance of the gas-absorbing media included in the RS and SA unit were inconclusive, and their effectiveness, lifetime, costs, and benefits must be further assessed before conclusions and recommendations can be made. The installation of effective air filtration devices in classrooms may be an important mitigation measure to help reduce the exposure of school children to indoor pollutants of outdoor origin including ultrafine particles and diesel particulate matter, especially at schools located near highly trafficked freeways, refineries, and other important sources of air toxics. Published 2012. This article is a US Government work and is in the public domain in the USA.

A Procedure for the Design of Air-Heated Ice-Prevention Systems

NASA Technical Reports Server (NTRS)

Neel, C. B.

1954-01-01

A procedure proposed for use in the design of air-heated systems for the continuous prevention of ice formation on airplane components is set forth. Required heat-transfer and air-pressure-loss equations are presented, and methods of selecting appropriate meteorological conditions for flight over specified geographical areas and for the calculation of water-drop-impingement characteristics are suggested. In order to facilitate the design, a simple electrical analogue was devised which solves the complex heat-transfer relationships existing in the thermal-system analysis. The analogue is described and an illustration of its application to design is given.

Fungal colonization of air filters for use in heating, ventilating, and air conditioning (HVAC) systems.

PubMed

Simmons, R B; Crow, S A

1995-01-01

New and used cellulosic air filters for HVAC systems including those treated with antimicrobials were suspended in vessels with a range of relative humidities (55-99%) and containing non-sterile potting soil which stimulates fungal growth. Most filters yielded fungi prior to suspension in the chambers but only two of 14 nontreated filters demonstrated fungal colonization following use in HVAC systems. Filters treated with antimicrobials, particularly a phosphated amine complex, demonstrated markedly less fungal colonization than nontreated filters. In comparison with nontreated cellulosic filters, fungal colonization of antimicrobial-treated cellulosic filters was selective and delayed.

Method and graphs for the evaluation of air-induction systems

NASA Technical Reports Server (NTRS)

Brajnikoff, George B

1953-01-01

Graphs have been developed for rapid evaluation of air-induction systems from considerations of their aerodynamic-performance parameters in combination with power-plant characteristics. The graphs cover the range of supersonic Mach numbers to 3.0. Examples are presented for an air-induction system and engine combination of two Mach numbers and two altitudes in order to illustrate the method and application of the graphs. The examples show that jet-engine characteristics impose restrictions on the use of fixed inlets if the maximum net thrusts are to be realized at all flight conditions. (author)

Fungal colonization of fiberglass insulation in the air distribution system of a multi-story office building: VOC production and possible relationship to a sick building syndrome.

PubMed

Ahearn, D G; Crow, S A; Simmons, R B; Price, D L; Noble, J A; Mishra, S K; Pierson, D L

1996-05-01

Complaints characteristic of those for sick building syndrome prompted mycological investigations of a modern multi-story office building on the Gulf coast in the Southeastern United States (Houston-Galveston area). The air handling units and fiberglass duct liner of the heating, ventilating and air conditioning system of the building, without a history of catastrophic or chronic water damage, demonstrated extensive colonization with Penicillium spp and Cladosporium herbarum. Although dense fungal growth was observed on surfaces within the heating-cooling system, most air samples yielded fewer than 200 CFU m-3. Several volatile compounds found in the building air were released also from colonized fiberglass. Removal of colonized insulation from the floor receiving the majority of complaints of mouldy air and continuous operation of the units supplying this floor resulted in a reduction in the number of complaints.

Fungal colonization of fiberglass insulation in the air distribution system of a multi-story office building: VOC production and possible relationship to a sick building syndrome

NASA Technical Reports Server (NTRS)

Ahearn, D. G.; Crow, S. A.; Simmons, R. B.; Price, D. L.; Noble, J. A.; Mishra, S. K.; Pierson, D. L.

1996-01-01

Complaints characteristic of those for sick building syndrome prompted mycological investigations of a modern multi-story office building on the Gulf coast in the Southeastern United States (Houston-Galveston area). The air handling units and fiberglass duct liner of the heating, ventilating and air conditioning system of the building, without a history of catastrophic or chronic water damage, demonstrated extensive colonization with Penicillium spp and Cladosporium herbarum. Although dense fungal growth was observed on surfaces within the heating-cooling system, most air samples yielded fewer than 200 CFU m-3. Several volatile compounds found in the building air were released also from colonized fiberglass. Removal of colonized insulation from the floor receiving the majority of complaints of mouldy air and continuous operation of the units supplying this floor resulted in a reduction in the number of complaints.

Design, construction, testing and evaluation of a residential ice storage air conditioning system

NASA Astrophysics Data System (ADS)

Santos, J. J.; Ritz, T. A.

1982-12-01

The experimental system was used to supply cooling to a single wide trailer and performance data were compared to a conventional air conditioning system of the some capacity. Utility rate information was collected from over one hundred major utility companies and used to evaluate economic comparison of the two systems. The ice storage system utilized reduced rate time periods to accommodate ice while providing continuous cooling to the trailer. The economic evaluation resulted in finding that the ice storage system required over 50% more energy than the conventional system. Although a few of the utility companies offered rate structures which would result in savings of up to $200 per year, this would not be enough to offset higher initial costs over the life of the storage system. Recommendations include items that would have to be met in order for an ice storage system to be an economically viable alternative to the conventional system.

Fungal contamination in hospital environments.

PubMed

Perdelli, F; Cristina, M L; Sartini, M; Spagnolo, A M; Dallera, M; Ottria, G; Lombardi, R; Grimaldi, M; Orlando, P

2006-01-01

To assess the degree of fungal contamination in hospital environments and to evaluate the ability of air conditioning systems to reduce such contamination. We monitored airborne microbial concentrations in various environments in 10 hospitals equipped with air conditioning. Sampling was performed with a portable Surface Air System impactor with replicate organism detection and counting plates containing a fungus-selective medium. The total fungal concentration was determined 72-120 hours after sampling. The genera most involved in infection were identified by macroscopic and microscopic observation. The mean concentration of airborne fungi in the set of environments examined was 19 +/- 19 colony-forming units (cfu) per cubic meter. Analysis of the fungal concentration in the different types of environments revealed different levels of contamination: the lowest mean values (12 +/- 14 cfu/m(3)) were recorded in operating theaters, and the highest (45 +/- 37 cfu/m(3)) were recorded in kitchens. Analyses revealed statistically significant differences between median values for the various environments. The fungal genus most commonly encountered was Penicillium, which, in kitchens, displayed the highest mean airborne concentration (8 +/- 2.4 cfu/m(3)). The percentage (35%) of Aspergillus documented in the wards was higher than that in any of the other environments monitored. The fungal concentrations recorded in the present study are comparable to those recorded in other studies conducted in hospital environments and are considerably lower than those seen in other indoor environments that are not air conditioned. These findings demonstrate the effectiveness of air-handling systems in reducing fungal contamination.

A new system to reduce formaldehyde levels improves safety conditions during gross veterinary anatomy learning.

PubMed

Nacher, Víctor; Llombart, Cristina; Carretero, Ana; Navarro, Marc; Ysern, Pere; Calero, Sebastián; Fígols, Enric; Ruberte, Jesús

2007-01-01

Dissection is a very useful method of learning veterinary anatomy. However, formaldehyde, which is widely used to preserve cadavers, is an irritant, and it has recently been classified as a carcinogen. In 1997, the Instituto Nacional de Seguridad e Higiene en el Trabajo [National Institute of Workplace Security and Hygiene] found that the levels of formaldehyde in our dissection room were above the threshold limit values. Unfortunately, no optimal substitute for formaldehyde is currently available. Therefore, we designed a new ventilation system that combines slow propulsion of fresh air from above the dissection table and rapid aspiration of polluted air from the perimeter. Formaldehyde measurements performed in 2004, after the introduction of this new system into our dissection laboratory, showed a dramatic reduction (about tenfold, or 0.03 ppm). A suitable propelling/aspirating air system successfully reduces the concentration of formaldehyde in the dissection room, significantly improving safety conditions for students, instructors, and technical staff during gross anatomy learning.

Center for Corporate Climate Leadership: Direct Fugitive Emissions from Refrigeration, Air Conditioning, Fire Suppression, and Industrial Gases

EPA Pesticide Factsheets

This guidance document focuses on several fugitive emissions sources that are common for organizations in many sectors: refrigeration and air conditioningsystems, fire suppression systems, and the purchase and release of industrial gases.

Development and evaluation of a radar air traffic control research task.

DOT National Transportation Integrated Search

1965-12-01

A system is described in which various elements of the radar air traffic controller's task can be presented repeatedly, reliably, and concurrently to each of six experimental subjects seated at separate task consoles. Programming of display condition...

UPDATE ON RADON MITIGATION RESEARCH IN SCHOOLS

EPA Science Inventory

The paper is an overview of research by EPA's Air and Energy Engineering Research Laboratory (AEERL) on radon mitigation in 47 schools since 1988. he structural and heating, ventilating, and air-conditioning (HVAC) system characteristics of the research schools are presented, alo...

Underground storage systems for high-pressure air and gases

NASA Technical Reports Server (NTRS)

Beam, B. H.; Giovannetti, A.

1975-01-01

This paper is a discussion of the safety and cost of underground high-pressure air and gas storage systems based on recent experience with a high-pressure air system installed at Moffett Field, California. The system described used threaded and coupled oil well casings installed vertically to a depth of 1200 ft. Maximum pressure was 3000 psi and capacity was 500,000 lb of air. A failure mode analysis is presented, and it is shown that underground storage offers advantages in avoiding catastrophic consequences from pressure vessel failure. Certain problems such as corrosion, fatigue, and electrolysis are discussed in terms of the economic life of such vessels. A cost analysis shows that where favorable drilling conditions exist, the cost of underground high-pressure storage is approximately one-quarter that of equivalent aboveground storage.

Physiological Responses to Microclimate Cooling Used By the Air Soldier Dressed at MOPP 4 in an Extreme Desert Condition: Effects of Six Configurations

DTIC Science & Technology

2012-12-01

USARIEM TECHNICAL REPORT PHYSIOLOGICAL RESPONSES TO MICROCLIMATE COOLING USED BY THE AIR SOLDIER DRESSED AT MOPP 4 IN AN...2012 2. REPORT TYPE 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Physiological Responses to Microclimate Cooling Used By the Air Soldier 5b. GRANT... Microclimate Cooling System MCG HI – Air Warrior Microclimate Cooling Garment Used in High Cooling Configuration MCG LO - Air Warrior Microclimate

75 FR 28632 - Federal Housing Administration (FHA)-Temporary Exemption From Compliance With FHA's Regulation on...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

... and balconies, walkways and driveways. iii The roofing, plumbing systems, electrical systems, heating and air conditioning systems; iv. All interiors; and v. All insulation and ventilation systems, as...

77 FR 34344 - Circular Welded Non-Alloy Steel Pipe From the Republic of Korea: Final Results of the Antidumping...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-11

... known as standard pipes and tubes and are intended for the low-pressure conveyance of water, steam, natural gas, air, and other liquids and gases in plumbing and heating systems, air- conditioning units, automatic sprinkler systems, and other related uses. Standard pipe may also be used for light load-bearing...

Time-Domain Finite Element Analysis of Nonlinear Breakdown Problems in High-Power-Microwave Devices and Systems

DTIC Science & Technology

2015-12-24

simulation of the electromagnetic- plasma interaction and the high-power microwave breakdown in air. Under the high pressure and high frequency condition of...the high-power air breakdown, the physical phenomenon is described using a nonlinearly coupled full-wave Maxwell and fluid plasma system. This...Challenges ........................................................................... 3 3.1.1 Plasma Fluid Model

Performance analysis of the electric vehicle air conditioner by replacing hydrocarbon refrigerant

NASA Astrophysics Data System (ADS)

Santoso, Budi; Tjahjana, D. D. D. P.

2017-01-01

The thermal comfort in passenger cabins needs an automotive air-conditioning system. The electric vehicle air conditioner system is driven by an electric compressor which includes a compressor and an electric motor. Almost air-conditioning system uses CFC-12, CFC-22 and HFC-134a as refrigerant. However, CFC-12 and CFC-22 will damage the ozone layer. The extreme huge global warming potentials (GWP) values of CFC-12, CFC-22, and HFC-134a represent the serious greenhouse effect of Earth. This article shows new experimental measurements and analysis by using a mixture of HC-134 to replace HFC-134a. The result is a refrigerating effect, the coefficient of performance and energy factor increase along with cooling capacity, both for HFC-134a and HC-134. The refrigerating effect of HC-134 is almost twice higher than HFC-134a. The coefficient of performance value of HC-134 is also 36.42% greater than HFC-134a. Then, the energy factor value of HC-134 is 3.78% greater than HFC-134a.

DOE Office of Scientific and Technical Information (OSTI.GOV)

C. Withers; Cummings, J.; Nigusse, B.

A new generation of full variable-capacity, central, ducted air-conditioning (AC) and heat pump units has come on the market, and they promise to deliver increased cooling (and heating) efficiency. They are controlled differently than standard single-capacity (fixed-capacity) systems. Instead of cycling on at full capacity and then cycling off when the thermostat is satisfied, they can vary their capacity over a wide range (approximately 40% to 118% of nominal full capacity), thus staying “on” for up to twice as many hours per day compared to fixed-capacity systems of the same nominal capacity. The heating and cooling capacity is varied bymore » adjusting the indoor fan air flow rate, compressor, and refrigerant flow rate as well as the outdoor unit fan air flow rate. Note that two-stage AC or heat pump systems were not evaluated in this research effort. The term dwell is used to refer to the amount of time distributed air spends inside ductwork during space-conditioning cycles. Longer run times mean greater dwell time and therefore greater exposure to conductive gains and losses.« less

System monitoring feedback in cinemas and harvesting energy of the air conditioning condenser

NASA Astrophysics Data System (ADS)

Pop, P. P.; Pop-Vadean, A.; Barz, C.; Latinovic, T.; Chiver, O.

2017-05-01

Our article monitors the degree of emotional involvement of the audience in the action film in theaters by measuring the concentration of CO2. The software performs data processing obtained dispersion sensors and displays data during the film. The software will also trigger the start of the air conditioning condenser where we can get harvesting energy by installing a piezoelectric device. Useful energy can be recovered from various waste produced in cinema. The time lag between actions and changes in environmental systems determines that decisions made now will affect subsequent generations and the future of our environment.

Measure Guideline: Optimizing the Configuration of Flexible Duct Junction Boxes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beach, R.; Burdick, A.

2014-03-01

This measure guideline offers additional recommendations to heating, ventilation, and air conditioning (HVAC) system designers for optimizing flexible duct, constant-volume HVAC systems using junction boxes within Air Conditioning Contractors of America (ACCA) Manual D guidance (Rutkowski, H. Manual D -- Residential Duct Systems, 3rd edition, Version 1.00. Arlington, VA: Air Conditioning Contractors of America, 2009.). IBACOS used computational fluid dynamics software to explore and develop guidance to better control the airflow effects of factors that may impact pressure losses within junction boxes among various design configurations (Beach, R., Prahl, D., and Lange, R. CFD Analysis of Flexible Duct Junction Boxmore » Design. Golden, CO: National Renewable Energy Laboratory, submitted for publication 2013). These recommendations can help to ensure that a system aligns more closely with the design and the occupants' comfort expectations. Specifically, the recommendations described herein show how to configure a rectangular box with four outlets, a triangular box with three outlets, metal wyes with two outlets, and multiple configurations for more than four outlets. Designers of HVAC systems, contractors who are fabricating junction boxes on site, and anyone using the ACCA Manual D process for sizing duct runs will find this measure guideline invaluable for more accurately minimizing pressure losses when using junction boxes with flexible ducts.« less

Experimental investigation on the thermal performance of heat storage walls coupled with active solar systems

NASA Astrophysics Data System (ADS)

Zhao, Chunyu; You, Shijun; Zhu, Chunying; Yu, Wei

2016-12-01

This paper presents an experimental investigation of the performance of a system combining a low-temperature water wall radiant heating system and phase change energy storage technology with an active solar system. This system uses a thermal storage wall that is designed with multilayer thermal storage plates. The heat storage material is expanded graphite that absorbs a mixture of capric acid and lauric acid. An experiment is performed to study the actual effect. The following are studied under winter conditions: (1) the temperature of the radiation wall surface, (2) the melting status of the thermal storage material in the internal plate, (3) the density of the heat flux, and (4) the temperature distribution of the indoor space. The results reveal that the room temperature is controlled between 16 and 20 °C, and the thermal storage wall meets the heating and temperature requirements. The following are also studied under summer conditions: (1) the internal relationship between the indoor temperature distribution and the heat transfer within the regenerative plates during the day and (2) the relationship between the outlet air temperature and inlet air temperature in the thermal storage wall in cooling mode at night. The results indicate that the indoor temperature is approximately 27 °C, which satisfies the summer air-conditioning requirements.

Capillary Tube and Thermostatic Expansion Valve Comparative Analysis in Water Chiller Air Conditioning

NASA Astrophysics Data System (ADS)

Wijaya Sunu, Putu; Made Rasta, I.; Anakottapary, Daud Simon; Made Suarta, I.; Cipta Santosa, I. D. M.

2018-01-01

The aims of this study to compares the performance characteristics of a water chiller air conditioning simulation equipped with thermostatic expansion valve (TEV) with those of a capillary tube. Water chiller system filled with the same charge of refrigerant. Comparative analyses were performed based on coefficient of performance (COP) and performance parameter of the refrigeration system, carried out at medium cooling load level with the ambient temperature of 29-31°C, constant compressor speed and fixed chilled water volume flowrate at 15 lpm. It was shown that the TEV system showed better energy consumption compared to that of capillary tube. From the coefficient of performance perspective, the thermostatic expansion valve system showed higher COP (± 21.4%) compared to that of capillary tube system.

[Hygienic assessment of conditions of the exploitation of facilities of the urban drainage system].

PubMed

Alikbayeva, L A; Iakubova, I Sh; Ryzhkov, A L; Lavrinova, A A; Sidorov, A A

The aim of the study was the hygienic characteristics of the location of sewage pumping stations (SPSs) in the residential area of the city and the assessment of working conditions for the staff. The features of the technological process at the SPSs resulted in the formation of specific working conditions characterized by the presence of a cooling microclimate, noise production, technological vibration, air pollution by microorganisms. The assessment of working conditions has allowed to refer them to the 3 class (harmful working conditions) of the 2 and 3 degree. Preventive measures for SPSs should include the use of equipment for cleaning the air of working zone, having a combined odourremoving and microbicidal action; the automation of the labor process; the installation of additional equipment for filtering air circulating in workplaces and emitting into the atmosphere; provision of sealing equipment with the use of noise insulating materials.

Analysis of the performance and space-conditioning impacts of dedicated heat-pump water heaters

NASA Astrophysics Data System (ADS)

Morrison, L.; Swisher, J.

1980-12-01

The operation of a newly marketed dedicated heat pump water heater (HPWH) which utilizes an air to water heat pump, costs about $1000 installed, and obtains a coefficient of performance (COP) of about 2.0 in laboratory and field tests, is a space conditioning benefit if an air conditioning load exists and a penalty if a space heating load exists. A simulation was developed to model the thermal performance of a residence with resistance baseboard heat, air conditioning, and either heat pump or resistance water heating. The building characteristics were adapted (Madison, Wisconsin; Washington, DC; and Ft. Worth, Texas) and the system was simulated for a year with typical weather data. For each city, HPWH COPs are calculated monthly and yearly. The water heating and space conditioning energy requirements of HPWH operation are compared with those of resistance water heater operation to determine the relative performance ratio of the HPWH.

Development of fuzzy air quality index using soft computing approach.

PubMed

Mandal, T; Gorai, A K; Pathak, G

2012-10-01

Proper assessment of air quality status in an atmosphere based on limited observations is an essential task for meeting the goals of environmental management. A number of classification methods are available for estimating the changing status of air quality. However, a discrepancy frequently arises from the quality criteria of air employed and vagueness or fuzziness embedded in the decision making output values. Owing to inherent imprecision, difficulties always exist in some conventional methodologies like air quality index when describing integrated air quality conditions with respect to various pollutants parameters and time of exposure. In recent years, the fuzzy logic-based methods have demonstrated to be appropriated to address uncertainty and subjectivity in environmental issues. In the present study, a methodology based on fuzzy inference systems (FIS) to assess air quality is proposed. This paper presents a comparative study to assess status of air quality using fuzzy logic technique and that of conventional technique. The findings clearly indicate that the FIS may successfully harmonize inherent discrepancies and interpret complex conditions.

Energy Retrofits Can Ease the Budget Squeeze.

ERIC Educational Resources Information Center

Nordeen, Howard

1983-01-01

Computer-based building management systems can cut the energy costs of heating, ventilating, and air conditioning (HVAC) systems in school buildings. Administrators are advised on how to choose the best system. (MLF)

Airborne irritant contact dermatitis due to synthetic fibres from an air-conditioning filter.

PubMed

Patiwael, Jiska A; Wintzen, Marjolein; Rustemeyer, Thomas; Bruynzeel, Derk P

2005-03-01

We describe 8 cases of occupational airborne irritant contact dermatitis in intensive care unit (ICU) employees caused by synthetic (polypropylene and polyethylene) fibres from an air-conditioning filter. Not until a workplace investigation was conducted, was it possible to clarify the unusual sequence of events. High filter pressure in the intensive care air-conditioning system, maintained to establish an outward airflow and prevent microorganisms from entering the ward, probably caused fibres from the filter to become airborne. Upon contact with air-exposed skin, fibres subsequently provoked skin irritation. Test periods in the ICU with varying filter pressures, in an attempt to improve environmental conditions, led to even higher filter pressure levels and more complaints. The sometimes-very-low humidity might have contributed to development of skin irritation. The fact that most patients recovered quickly after treatment with emollients and changing the filters made it most likely that the airborne dermatitis was of an irritant nature.

Implementation of pressurized air injection system in a Kaplan prototype for the reduction of vibration caused by tip vortex cavitation

NASA Astrophysics Data System (ADS)

Rivetti, A.; Angulo, M.; Lucino, C.; Hene, M.; Capezio, O.; Liscia, S.

2016-11-01

Blade tip cavitation is a well-known phenomenon that affects the performance of large-diameter Kaplan turbines and induces structural vibration. Injection of pressurized air has been found to yield promising results in reducing those damaging effects. In this work, the results of an experimental test of air injection on a 9.5-m-diameter Kaplan turbine are reported. Experiments were performed for several load conditions and for two different net heads. Accelerations, pressure pulsation and noise emission were monitored for every tested condition. Results show that, at the expense of a maximum efficiency drop of 0.2%, air injection induces a decrease on the level of vibration from 57% up to 84%, depending on the load condition. Such decrease is seen to be proportional to the air flow rate, in the range from 0.06 to 0.8‰ (respect to the discharge at the best efficiency point).

Programmatic Environmental Assessment for Base General Plan Development, Schriever Air Force Base, Colorado

DTIC Science & Technology

2012-06-01

will not involve an element of high risk or uncertainty on the human environment, and its effects on the quality of the human environment are not...Information System HAPs Hazardous air pollutants HAZMAT Hazardous Material HVAC heating, ventilation , and air conditioning HUD U.S. Housing and...Engineers USAF Unites States Air Force USC United States Code USEPA United States Environmental Protection Agency USFWS United States Fish and Wildlife

Pilot retrofit test of refrigerant R-134a for GDSCC

NASA Technical Reports Server (NTRS)

Albus, J.; Brown, B.; Dungao, M.; Spencer, G.

1994-01-01

NASA has issued an interim policy requiring all of its Centers to eliminate consumption (purchase) of stratospheric ozone-depleting substances, including chlorofluorocarbons (CFC's), by 1995. Also, plans must be outlined for the eventual phase out of their usage. The greatest source of CFC consumption and usage at the Goldstone Deep Space Communications Complex is refrigerant R-12, which is used in many of the facility's air-conditioning systems. A pilot retrofit test shows that retrofitting R-12 air-conditioning systems with hydrofluorocarbon R-13a would be a workable means to comply with the R-12 portion of NASA's policy. Results indicate acceptable cost levels and nearly equivalent system performance.

3D quantification of microclimate volume in layered clothing for the prediction of clothing insulation.

PubMed

Lee, Yejin; Hong, Kyunghi; Hong, Sung-Ae

2007-05-01

Garment fit and resultant air volume is a crucial factor in thermal insulation, and yet, it has been difficult to quantify the air volume of clothing microclimate and relate it to the thermal insulation value just using the information on the size of clothing pattern without actual 3D volume measurement in wear condition. As earlier methods for the computation of air volume in clothing microclimate, vacuum over suit and circumference model have been used. However, these methods have inevitable disadvantages in terms of cost or accuracy due to the limitations of measurement equipment. In this paper, the phase-shifting moiré topography was introduced as one of the 3D scanning tools to measure the air volume of clothing microclimate quantitatively. The purpose of this research is to adopt a non-contact image scanning technology, phase-shifting moiré topography, to ascertain relationship between air volume and insulation value of layered clothing systems in wear situations where the 2D fabric creates new conditions in 3D spaces. The insulation of vests over shirts as a layered clothing system was measured with a thermal manikin in the environmental condition of 20 degrees C, 65% RH and air velocity of 0.79 m/s. As the pattern size increased, the insulation of the clothing system was increased. But beyond a certain limit, the insulation started to decrease due to convection and ventilation, which is more apparent when only the vest was worn over the torso of manikin. The relationship between clothing air volume and insulation was difficult to predict with a single vest due to the extreme openings which induced active ventilation. But when the vest was worn over the shirt, the effects of thickness of the fabrics on insulation were less pronounced compared with that of air volume. In conclusion, phase-shifting moiré topography was one of the efficient and accurate ways of quantifying air volume and its distribution across the clothing microclimate. It is also noted that air volume becomes more crucial factor in predicting thermal insulation when clothing is layered.

5. VIEW OF VENTILATION HOUSES AND ROOF MONITOR FROM SOUTHEAST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. VIEW OF VENTILATION HOUSES AND ROOF MONITOR FROM SOUTHEAST CORNER OF ROOF. ROOF MONITOR WINDOWS HAVE BEEN INFILLED WITH BRICK. THE VENTILATION HOUSES ARE PART OF THE ORIGINAL CENTRAL AIR CONDITIONING SYSTEM AND CONTAINED AIR WASHERS, FANS AND OTHER HUMIDFYING EQUIPMENT FROM PARKS-CRAMER COMPANY OF FITCHBURG, MASSACHUSETTS. LOCATING THIS EQUIPMENT ON THE ROOF MADE IT UNNECESSARY TO CONSTRUCT A FULL BASEMENT, AND THEREFORE LOWERED CONSTRUCTION COSTS. THIS ARRANGEMENT ALSO PUT THE AIR CONDITIONING EQUIPMENT CLOSEST TO THE TOP FLOOR SPINNING ROOM, WHICH HAD THE GREATEST COOLING REQUIREMENTS. - Stark Mill, 117 Corinth Road, Hogansville, Troup County, GA

The 10 MWe Solar Thermal Central Receiver Pilot Plant: Solar facilities design integration. Pilot-plant station manual (RADL Item 2-1). Volume 1: System description

NASA Astrophysics Data System (ADS)

1982-09-01

The complete Barstow Solar Pilot Plant is described. The plant requirements and general description are presented, the mechanical, electric power, and control and instrumentation systems as well as civil engineering and structural aspects and the station buildings are described. Included in the mechanical systems are the heliostats, receiver, thermal storage system, beam characterization system, steam, water, nitrogen, and compressed air systems, chemical feed system, fire protection system, drains, sumps and the waste disposal systems, and heating, ventilating, and air conditioning systems.

[Immunologic response to microorganisms from a polluted ventilation system in a working environment].

PubMed

Cernelc, S; Vozelj, M

1991-01-01

Authors point out the morbidity of employees working in ventilation systems contaminated with various microorganisms. They analysed 96 workers exposed to air conditioning system (Group A), and 71 workers (Group B) breathing normal ambient air. The workers of both groups were subjected clinically by functionally and immunologically. Preparation of antigens "MMM" (Monday morning miseries) was used as an original method by Ajello et al. for producing antigens from systemic mycotic agents and subsequently modified. The aim of the present study is to evaluate the possibility of using ELISA in clinical practice for respiratory allergy diagnosis, and especially Hypersensitivity pneumonitis. Atopic status was determined by skin prick tests with common airborne allergens including Dermatophagoides pteronyssinus, ragweed, grasses and Aspergillus fumigatus., by Enzygnost--IgE (Behringwerke AG, Marburg) and for specific IgE by RAST technique (Pharmacia, Uppsala). The skin prick tests were performed with "MMM"-antigens. PEFR (Peak Expiratory Flow-Rate) was measured by using a Wright's peak flow meter. PEFR was recorded on Monday (first day at work) and Friday (the end of the working week). Measured values of PEFR in both groups of employees from Monday to Friday were elaborated by the Wilcoxon test. Culture of scrapings from air conditioning vents were obtained and water from the humidifier system also cultured. They were grown: T. vulgaris, Aspergillus fumigatus, Thermoactinomyces vulgaris and others. Results of questionnaires, clinical evaluation and diagnostical procedures in employees of Group A and B are as follows: Thirty eight workers in Group A had a positive clinical history of "Monday illness". In the symptomatic Group A we found in 8 cases abnormal chest roentgenogram. Further, there was no correlation between the presence of antibodies (ELISA) against MMM and pulmonary function abnormalities, as measured by either spirometry or DLCO. Further, we found good agreement between ELISA and prick test results with antigen MMM. Wilcoxon test showed a statistically significant difference between the two groups (0.01). The median or central value of PEFR reduction in Group A is 10.23 per cent, and in Group B 1.49 per cent. A 30 per cent reduction of PEFR was observed in 5.21 per cent of subjects in Group A. Exposure to ventilation systems contaminated with Thermophilic actinomyces may be responsible for increased morbidity and reduced performance of employees working in air conditioning systems. Particularly the main filter should be checked regularly. Moreover, regular microbiologic examinations of dust and water from air preventing chronic obstructive lung diseases in employees working in areas served by contaminated air conditioning systems.

Design and Sizing of the Air Revitalization System for Altair Lunar Lander

NASA Technical Reports Server (NTRS)

Allada, Rama Kumar

2009-01-01

Designing closed-loop Air Revitalization Systems (ARS) for human spaceflight applications requires a delicate balance between designing for system robustness while minimizing system power and mass requirements. This presentation will discuss the design of the ARS for the Altair Lunar Lander. The presentation will illustrate how dynamic simulations, using Aspen Custom Modeler, were used to develop a system configuration with the ability to control atmospheric conditions under a wide variety of circumstances while minimizing system mass/volume and the impact on overall power requirements for the Lander architecture.

A System Dynamic Model of Leader Emergence

DTIC Science & Technology

2008-03-01

Engineering and Management Air Force Institute of Technology Air University Air Education and Training Command In Partial Fulfillment of the...which in turn, have impacts on the success of the leader and the organization (Jung & Avolio, 1999). Group members can modify behaviors such as dissent...Contingency approaches to leadership suggest that environmental conditions combined with leader behavoirs, determine leader effectiveness (Judge

Causes of Indoor Air Quality Problems in Schools: Summary of Scientific Research.

ERIC Educational Resources Information Center

Bayer, Charlene W.; Crow, Sidney A.; Fischer, John

Research show that one in five U.S. schools has indoor air quality (IAQ) problems; 36 percent have inadequate heating, ventilation, and air conditioning (HVAC) systems; and there appears to be a correlation between IAQs and the proportion of a school's students coming from low-income households. This report examines the IAQ issue in U.S. public…

CleAir Monitoring System for Particulate Matter: A Case in the Napoleonic Museum in Rome

PubMed Central

Bonacquisti, Valerio; Di Michele, Marta; Frasca, Francesca; Chianese, Angelo; Siani, Anna Maria

2017-01-01

Monitoring the air particulate concentration both outdoors and indoors is becoming a more relevant issue in the past few decades. An innovative, fully automatic, monitoring system called CleAir is presented. Such a system wants to go beyond the traditional technique (gravimetric analysis), allowing for a double monitoring approach: the traditional gravimetric analysis as well as the optical spectroscopic analysis of the scattering on the same filters in steady-state conditions. The experimental data are interpreted in terms of light percolation through highly scattering matter by means of the stretched exponential evolution. CleAir has been applied to investigate the daily distribution of particulate matter within the Napoleonic Museum in Rome as a test case. PMID:28892016

Indoor air quality at the Correr Museum, Venice, Italy.

PubMed

Camuffo, D; Brimblecombe, P; Van Grieken, R; Busse, H J; Sturaro, G; Valentino, A; Bernardi, A; Blades, N; Shooter, D; De Bock, L; Gysels, K; Wieser, M; Kim, O

1999-09-15

Two multidisciplinary field surveys, one in winter and the other in summer have monitored the indoor microclimate, air pollution, deposition and origin of the suspended particulate matter and microorganisms of the Correr Museum, Venice. In addition, this study was focused to identify the problems caused by the heating and air conditioning system (HAC) and the effects due to the presence of carpets. Heating and air conditioning systems (HACs), when chiefly designed for human welfare, are not suitable for conservation and can cause dangerous temperature and humidity fluctuations. Improvements at the Correr Museum have been achieved with the assistance of environmental monitoring. The carpet has a negative influence as it retains particles and bacteria which are resuspended each time people walk on it. The indoor/outdoor pollutants ratio is greater in the summertime, when doors and windows are more frequently open to allow for better ventilation, illustrating that this ratio is mainly governed by the free exchange of the air masses. The chemical composition, size and origin of the suspended particulate matter have been identified, as well as the bacteria potentially dangerous to the paintings. Some general suggestions for improving indoor air quality are reported in the conclusions.

Factors defining value and direction of thermal pressure between the mine shafts and impact of the general mine natural draught on ventilation process of underground mining companies

NASA Astrophysics Data System (ADS)

Nikolaev, A. V.; Alymenko, N. I.; Kamenskikh, A. A.; Alymenko, D. N.; Nikolaev, V. A.; Petrov, A. I.

2017-10-01

The article specifies measuring data of air parameters and its volume flow in the shafts and on the surface, collected in BKPRU-2 (Berezniki potash plant and mine 2) («Uralkali» PJSC) in normal operation mode, after shutdown of the main mine fan (GVU) and within several hours. As a result of the test it has been established that thermal pressure between the mine shafts is active continuously regardless of the GVU operation mode or other draught sources. Also it has been discovered that depth of the mine shafts has no impact on thermal pressure value. By the same difference of shaft elevation marks and parameters of outer air between the shafts, by their different depth, thermal pressure of the same value will be active. Value of the general mine natural draught defined as an algebraic sum of thermal pressure values between the shafts depends only on the difference of temperature and pressure of outer air and air in the shaft bottoms on condition of shutdown of the air handling system (unit-heaters, air conditioning systems).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scofield, C.M.; Des Champs, N.H.

This article examines a design concept for classroom air conditioning systems that guarantees minimum ventilation rates are met. The topics of the article include new ventilation requirements, design concept, outside air induction diffuser, low-velocity ducts and plenums, the relationship of humidity to school absenteeism rates, retrofit applications, and saving energy.

46 CFR 194.15-5 - Ventilation.

Code of Federal Regulations, 2014 CFR

2014-10-01

... CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory § 194... be equipped with acceptable flame screens. (b) Chemical laboratories shall be equipped with power...) Ventilation of air conditioning systems serving the chemical laboratory shall be designed so that air cannot...

46 CFR 194.15-5 - Ventilation.

Code of Federal Regulations, 2012 CFR

2012-10-01

... CONTROL OF EXPLOSIVES AND OTHER HAZARDOUS MATERIALS Chemistry Laboratory and Scientific Laboratory § 194... be equipped with acceptable flame screens. (b) Chemical laboratories shall be equipped with power...) Ventilation of air conditioning systems serving the chemical laboratory shall be designed so that air cannot...