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Sample records for air-conditioning equipment lorentz

  1. Study of thermodynamic properties of HFC refrigerant mixtures for Loretz-cycled niew generation air-conditioning equipment; Lorentz cycle ka shinsedai kucho kikiyo HFC kei kongo reibai no netsu rikigaku seishitsu ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, K.; Sato, H. [Keio University, Tokyo (Japan). Faculty of Science and Technology

    1997-02-01

    This paper describes thermodynamic properties of HFC refrigerant mixtures for Lorentz-cycled new generation air-conditioning equipment. Equipment has been completed for simultaneous measurement of density and vapor-liquid equilibrium property, accurate measurement of latent heat of vaporization, and accurate measurement of specific heat at constant pressure in liquid phase. Final adjustment and preliminary measurements are currently conducted. Through analytical investigation using actually measured data of thermodynamic properties of HFC refrigerant mixtures, five state equations were obtained, i.e., modified Peng-Robinson state equation which can reproduce the vapor-liquid equilibrium property of refrigerant mixtures, modified Patel-Teja state equation, Helmholtz function type state equation which is applicable in the whole fluid region of refrigerant mixtures, and so on. An evaluation test equipment has been fabricated as a trial for Lorentz-cycled air-conditioning equipments using HFC refrigerant mixtures, and demonstration test is conducted to confirm the validity. 9 refs., 5 figs.

  2. Control of Computer Room Air Conditioning using IT Equipment Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Geoffrey C.; Storey, Bill; Patterson, Michael K.

    2009-09-30

    The goal of this demonstration was to show how sensors in IT equipment could be accessed and used to directly control computer room air conditioning. The data provided from the sensors is available on the IT network and the challenge for this project was to connect this information to the computer room air handler's control system. A control strategy was developed to enable separate control of the chilled water flow and the fans in the computer room air handlers. By using these existing sensors in the IT equipment, an additional control system is eliminated (or could be redundant) and optimal cooling can be provided saving significant energy. Using onboard server temperature sensors will yield significant energy reductions in data centers. Intel hosted the demonstration in its Santa Clara, CA data center. Intel collaborated with IBM, HP, Emerson, Wunderlich-Malec Engineers, FieldServer Technologies, and LBNL to install the necessary components and develop the new control scheme. LBNL also validated the results of the demonstration.

  3. 40 CFR 86.1832-01 - Optional equipment and air conditioning for test vehicles.

    Science.gov (United States)

    2010-07-01

    ... Optional equipment and air conditioning for test vehicles. For test vehicles selected under §§ 86.1822-01... be expected to influence emissions include, but are not limited to: air conditioning, power steering...) Except for air conditioning, where it is expected that 33 percent or less of a car line, within a...

  4. 24 CFR 3280.813 - Outdoor outlets, fixtures, air-conditioning equipment, etc.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Outdoor outlets, fixtures, air-conditioning equipment, etc. 3280.813 Section 3280.813 Housing and Urban Development Regulations Relating to... Electrical Systems § 3280.813 Outdoor outlets, fixtures, air-conditioning equipment, etc. (a)...

  5. An Analysis of Price Determination and Markups in the Air-Conditioning and Heating Equipment Industry

    Energy Technology Data Exchange (ETDEWEB)

    Dale, Larry; Millstein, Dev; Coughlin, Katie; Van Buskirk, Robert; Rosenquist, Gregory; Lekov, Alex; Bhuyan, Sanjib

    2004-01-30

    In this report we calculate the change in final consumer prices due to minimum efficiency standards, focusing on a standard economic model of the air-conditioning and heating equipment (ACHE) wholesale industry. The model examines the relationship between the marginal cost to distribute and sell equipment and the final consumer price in this industry. The model predicts that the impact of a standard on the final consumer price is conditioned by its impact on marginal distribution costs. For example, if a standard raises the marginal cost to distribute and sell equipment a small amount, the model predicts that the standard will raise the final consumer price a small amount as well. Statistical analysis suggest that standards do not increase the amount of labor needed to distribute equipment the same employees needed to sell lower efficiency equipment can sell high efficiency equipment. Labor is a large component of the total marginal cost to distribute and sell air-conditioning and heating equipment. We infer from this that standards have a relatively small impact on ACHE marginal distribution and sale costs. Thus, our model predicts that a standard will have a relatively small impact on final ACHE consumer prices. Our statistical analysis of U.S. Census Bureau wholesale revenue tends to confirm this model prediction. Generalizing, we find that the ratio of manufacturer price to final consumer price prior to a standard tends to exceed the ratio of the change in manufacturer price to the change in final consumer price resulting from a standard. The appendix expands our analysis through a typical distribution chain for commercial and residential air-conditioning and heating equipment.

  6. Proposal for energy saving in air conditioning equipment; Propuesta para ahorro energetico en acondicionadores de aire

    Energy Technology Data Exchange (ETDEWEB)

    Solis Recendez, Daniel H [Division de Ingenieria Electrica, Universidad Nacional Autonoma de Mexico (Mexico)

    2008-10-15

    In the last decades, the air conditioning systems have become a crucial part in the search from comfort in extreme climates. Nevertheless, they have also become one of the greatest energy consumers. In this article it is proposed that the final conditions that the air conditioning equipment looks for not to be fixed, but variable in respect to a certain comfort zone. This zone is a variation of the used one in the bio-climatic chart of Olgyay that considers the rapidity whereupon the reached conditions tend to leave the comfort zone. It is analyzed how to choose the point on the zone that costs less energy in arriving to it. [Spanish] En las ultimas decadas, los sistemas de aire acondicionado se han vuelto una parte crucial en la busqueda de confort en climas extremosos. Sin embargo, tambien se han vuelto de los mayores consumidores de energia. En este articulo se propone que las condiciones finales que busquen lograr los acondicionadores no sean fijas, si no variables respecto a una determinada zona de confort. Dicha zona es una variacion de la utilizada en la carta bioclimatica de Olgyay, que considera la rapidez con que las condiciones alcanzadas tienden a abandonar la zona de confort. Se discute como elegir el punto sobre la zona que cueste menos energia en llegara el.

  7. Refrigeration and Air Conditioning Equipment, 11-9. Military Curriculum Materials for Vocational and Technical Education.

    Science.gov (United States)

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This military-developed text consists of three blocks of instructional materials for use by those studying to become refrigeration and air conditioning specialists. Covered in the individual course blocks are the following topics: refrigeration and trouble analysis, thermodynamics, and principles of refrigeration; major components and domestic and…

  8. COP Evaluation for a Membrane Liquid Desiccant Air Conditioning System Using Four Different Heating Equipment

    OpenAIRE

    Abdel-Salam, Ahmed; Simonson, Carey

    2015-01-01

    Liquid desiccant air conditioning (LDAC) is a promising technology in terms of energy efficiency, comfort and indoor air quality. The major components of a LDAC system are the dehumidifier and regenerator. The most commonly used design of dehumidifiers/regenerators is the packed-bed, which might result in the entrainment of desiccant droplets in air streams. A promising solution for the entrainment of desiccant droplets in air streams is to use a liquid-to-air membrane energy exchanger (LAMEE...

  9. The correct insulation of refrigeration and air-conditioning equipment - Part 1: correct professional workmanship; Die fachgerechte Verklebung

    Energy Technology Data Exchange (ETDEWEB)

    Weber, M.

    2010-07-01

    This first article of series of six takes a look at correct professional workmanship when insulating cooling and air-conditioning equipment. Elastomer insulation materials and their use in refrigeration and air-conditioning installations is discussed. The advantages offered by this type of insulation are noted. Also, the problems that can be encountered if the materials are not correctly installed are discussed. Typical mistakes that can be made are looked at. These include erroneous dimensional measurements and cutting, as well as bad jointing and gluing; especially when jointing to foreign materials and around support structures. In particular, problems that can be encountered when insulating piping in refrigeration installations are discussed. Recommendations for dimensioning and separation distance for piping are made.

  10. R and D opportunities for commercial HVAC (heating, air conditioning, and ventilation) equipment

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, S.A.; Zaloudek, F.R.

    1987-03-01

    The overall objective of this project is to identify and characterize generic HVAC equipment research that will provide the best investment opportunities for DOE R and D funds. The prerequisites of a DOE research program include research efforts that are potentially significant in energy conservation impact and that are cost-effective, long-term, and high risk. These prerequisites form the basic guidelines for the R and D opportunities assessed. The assessment excludes the R and D areas that have potential or current private sector sponsors. Finally, R and D areas which are included in DOE programs generally are not addressed.

  11. Understanding the Dehumidification Performance of Air-Conditioning Equipment at Part-Load Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Don B. Shirey III; Hugh I. Henderson Jr; Richard A. Raustad

    2006-01-01

    Air conditioner cooling coils typically provide both sensible cooling and moisture removal. Data from a limited number of field studies (Khattar et al. 1985; Henderson and Rengarajan 1996; Henderson 1998) have demonstrated that the moisture removal capacity of a cooling coil degrades at part-load conditions--especially when the supply fan operates continuously while the cooling coil cycles on and off. Degradation occurs because moisture that condenses on the coil surfaces during the cooling cycle evaporates back into air stream when the coil is off. This degradation affects the ability of cooling equipment to maintain proper indoor humidity levels and may negatively impact indoor air quality. This report summarizes the results of a comprehensive project to better understand and quantify the moisture removal (dehumidification) performance of cooling coils at part-load conditions. A review of the open literature was initially conducted to learn from previous research on this topic. Detailed performance measurements were then collected for eight cooling coils in a controlled laboratory setting to understand the impact of coil geometry and operating conditions on transient moisture condensation and evaporation by the coils. Measurements of cooling coil dehumidification performance and space humidity levels were also collected at seven field test sites. Finally, an existing engineering model to predict dehumidification performance degradation for single-stage cooling equipment at part-load conditions (Henderson and Rengarajan 1996) was enhanced to include a broader range of fan control strategies and an improved theoretical basis for modeling off-cycle moisture evaporation from cooling coils. The improved model was validated with the laboratory measurements, and this report provides guidance for users regarding proper model inputs. The model is suitable for use in computerized calculation procedures such as hourly or sub-hourly building energy simulation programs (e

  12. Performance and evaluation of gas engine driven rooftop air conditioning equipment at the Willow Grove (PA) Naval Air Station

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, P.R.; Conover, D.R.

    1993-05-01

    In a field evaluation conducted for the US Department of Energy (DOE) Office of Federal Energy Management Program (FEMP), the Pacific Northwest Laboratory (PNL) examined the performance of a new US energy-related technology under the FEMP Test Bed Demonstration Program. The technology was a 15-ton natural gas engine driven roof top air conditioning unit. Two such units were installed on a naval retail building to provide space conditioning to the building. Under the Test Bed Demonstration Program, private and public sector interests are focused to support the installation and evaluation of new US technologies in the federal sector. Participating in this effort under a Cooperative Research and Development Agreement (CRADA) with DOE were the American Gas Cooling Center, Philadelphia Electric Company, Thermo King Corporation, and the US Naval Air Station at Willow Grove, Pennsylvania. Equipment operating and service data as well as building interior and exterior conditions were secured for the 1992 cooling season. Based on a computer assessment of the building using standard weather data, a comparison was made with the energy and operating costs associated with the previous space conditioning system. Based on performance during the 1992 cooling season and adjusted to a normal weather year, the technology will save the site $6,000/yr in purchased energy costs. An additional $9,000 in savings due to electricity demand ratchet charge reductions will also be realized. Detailed information on the technology, the installation, and the results of the technology test are provided to illustrate the advantages to the federal sector of using this technology. A history of the CRADA development process is also reported.

  13. Environmental impact of the programs of substitution of room type air conditioning equipment; Impacto ambiental de los programas de sustitucion de equipos de aire tipo cuarto

    Energy Technology Data Exchange (ETDEWEB)

    Alarcon Aleman, Jose Mauricio [OLADE, Quito (Ecuador)

    2002-09-01

    The present article approaches in a general way the relation that exists between the environment and the saving of electrical energy, especially in the Programs of Demand Side Management (DSM). In particular form the potential environmental impacts are described, derived of the use and the discard of the room type air conditioning equipment, goes deep into the characteristics of their cooling fluids, as well as in the relation that these keep with the protocols of Montreal and Kyoto. Finally, this article comments the incidence which have, the manufacturers as the institutions that implement DSM programs, on the environmental part of the programs of substitution of room type air conditioning equipment. In addition it is briefly described, the pilot program developed by Fideicomiso para el Ahorro de Energia Electrica (FIDE) as a successful case. [Spanish] En forma general, el presente articulo aborda la relacion que existe entre el medio ambiente y el ahorro de energia electrica, especialmente en los Programas de Administracion por el Lado de la Demanda (ALD). En forma particular se describen los impactos ambientales potenciales, derivados del uso y desecho de los equipos de aire acondicionado tipo cuarto, se ahonda en las caracteristicas de sus refrigerantes, asi como en la relacion que estos guardan con los protocolos de Montreal y Kioto. Finalmente, se comenta la incidencia que tienen, tanto los fabricantes como las instituciones que implementan programas de ALD, sobre la parte ambiental de los programas de sustitucion de equipos de aire acondicionado tipo cuarto. Ademas se describe brevemente, el programa piloto desarrollado por el Fideicomiso para el Ahorro de Energia Electrica (FIDE) como un caso exitoso.

  14. SESSA: Expert system for the selection of air conditioning equipment; SESEAA: Sistema experto para la seleccion de equipos de aire acondicionado

    Energy Technology Data Exchange (ETDEWEB)

    Kemper Valverde, Nicolas; Cardenas Perez, Edgar [Laboratorio de Sistemas Inteligentes, Centro de Instrumentos de la Universidad Nacional Autonoma de Mexico (UNAM), Mexico, D. F. (Mexico)

    1998-12-31

    The problem of selecting air conditioning and refrigeration equipment is quite wide and complex, since it encompasses from the application of the basic principles of physics and of thermodynamics up to the classic engineering design problems; these in turn can be numberless since they vary from place to place depending on multiple factors such as the region geographic and economic conditions. On the other hand, account most be taken of several elements such as windows, walls, and its specific geographical orientation, roofs, floors, partitions, equipment, lighting, etc., all this exerts influence in the complexity that represents the selection process. This paper describes a useful informatics tool to make it easy the selection process in air conditioning installations, taking into account multiple saving and efficient use of energy criteria, reflected in the operation process of these installations. [Espanol] El problema de seleccion de sistemas de aire acondicionado y de refrigeracion es bastante amplio y complejo, ya que abarca desde la aplicacion de los principios basicos de la fisica y la termodinamica hasta los problemas clasicos de diseno de ingenieria; estos a la vez pueden ser innumerables ya que varian de un lugar a otro y de un proyecto a otro, dependiendo de multiples factores tales como las condiciones geograficas y economicas de la region. Por otra parte se deben tomar en cuenta diversos elementos como son: ventanas, muros y sus orientaciones especificas, techos, pisos, particiones, equipos, iluminacion, etc., todo esto influye en la complejidad que representa el proceso de seleccion. En el presente trabajo se describe una herramienta informatica para facilitar el proceso de seleccion de instalaciones de aire acondicionado, tomando en cuenta multiples criterios de ahorro y uso eficiente de energia que se reflejan durante el proceso de operacion de estas instalaciones.

  15. REACH. Air Conditioning Units.

    Science.gov (United States)

    Garrison, Joe; And Others

    As a part of the REACH (Refrigeration, Electro-Mechanical, Air-Conditioning, Heating) electromechanical cluster, this student manual contains individualized instructional units in the area of air conditioning. The instructional units focus on air conditioning fundamentals, window air conditioning, system and installation, troubleshooting and…

  16. Performance and evaluation of gas engine driven rooftop air conditioning equipment at the Willow Grove (PA) Naval Air Station. Interim report, 1992 cooling season

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, P.R.; Conover, D.R.

    1993-05-01

    In a field evaluation conducted for the US Department of Energy (DOE) Office of Federal Energy Management Program (FEMP), the Pacific Northwest Laboratory (PNL) examined the performance of a new US energy-related technology under the FEMP Test Bed Demonstration Program. The technology was a 15-ton natural gas engine driven roof top air conditioning unit. Two such units were installed on a naval retail building to provide space conditioning to the building. Under the Test Bed Demonstration Program, private and public sector interests are focused to support the installation and evaluation of new US technologies in the federal sector. Participating in this effort under a Cooperative Research and Development Agreement (CRADA) with DOE were the American Gas Cooling Center, Philadelphia Electric Company, Thermo King Corporation, and the US Naval Air Station at Willow Grove, Pennsylvania. Equipment operating and service data as well as building interior and exterior conditions were secured for the 1992 cooling season. Based on a computer assessment of the building using standard weather data, a comparison was made with the energy and operating costs associated with the previous space conditioning system. Based on performance during the 1992 cooling season and adjusted to a normal weather year, the technology will save the site $6,000/yr in purchased energy costs. An additional $9,000 in savings due to electricity demand ratchet charge reductions will also be realized. Detailed information on the technology, the installation, and the results of the technology test are provided to illustrate the advantages to the federal sector of using this technology. A history of the CRADA development process is also reported.

  17. Rational use of energy in air conditioning equipment, through an appropriate selection of the main equipment; Uso racional de la energia en equipos de aire acondicionado, mediante la eleccion apropiada del equipo principal

    Energy Technology Data Exchange (ETDEWEB)

    Reyes Zuniga, Jose de Jesus; Herrera Ramos, Manuel [Instituto Mexicano del Petroleo (Mexico)

    1996-07-01

    This paper presents an analysis to diminish the consumption of energy in central air conditioning equipment through an appropriate selection of the equipment. The analysis shows the levels of security and toxicity of the refrigerant, the operational, constructive and economic advantages of the equipment, taking as reference the cooling demand and expenses of energy consumption, as well as the ecological impact derived from the use of the refrigerant. Finally, an economic analysis is presented, involving the expenses of the equipment, operation, maintenance, costs of the consumption of used fluids, et cetera. [Spanish] Uso racional de la energia en equipos de aire acondicionado, mediante la eleccion apropiada del equipo principal. Este trabajo presenta un analisis para disminuir el consumo de energia en los equipos centrales de aire acondicionado mediante la seleccion apropiada del equipo. El analisis muestra los niveles de seguridad y toxicidad del refrigerante, las ventajas operativas, constructivas y economicas del equipo, tomando como referencia la demanda de enfriamiento y gastos de consumo de energia, asi como el impacto ecologico derivado de su empleo del refrigerante. Finalmente, se presenta un analisis economico, involucrando los gastos del equipo, operacion, mantenimiento, costos de consumos de fluidos utilizados, etcetera.

  18. 制冷空调设备绿色设计的技术和实践探讨%Technical and Practical Discussions on Green Design of Refrigeration and Air Conditioning Equipments

    Institute of Scientific and Technical Information of China (English)

    朱斌祥; 张缓缓; 曲本连; 彭飞; 李韶强

    2015-01-01

    空调行业作为能源消耗和环境污染的重要源流,对于节能环保承担着重要责任。制冷空调设备绿色设计的应用研究日益受到人们的重视。本文指出了制冷空调产品进行绿色设计的必要性,分析了制冷空调绿色设计中的主要因素及主要内容,对于目前制冷空调产品提出了相应的绿色设计方法,还提出了绿色设计在制冷空调产品中的应用策略,以及绿色产品的评价指标。%As an important part of energy consumption and environment pollution, the air conditioning industry takes a great responsibility for energy saving and environment protection. More and more attentions have been paid on the application investigation in the green design of refrigeration and air conditioning equipments. In the paper the necessity to conduct the green design of refrigeration and air conditioning equipments is pointed out. A series of major factors and technologies are analyzed. The green design methods are proposed for the practical refrigeration and air conditioning equipment. In addition, the application strategy of green design in the air conditioning and refrigeration field is presented and the evaluation indicators on green products are concluded.

  19. Evaluation of energy saving in pilot projects of window type air conditioning equipment in the domestic sector; Evaluacion del ahorro de energia en proyectos pilotos en equipos de aire acondicionado tipo ventana en el sector domestico

    Energy Technology Data Exchange (ETDEWEB)

    Duran Ramirez, Ricardo [Comision Nacional para el Ahorro de Energia, Mexico, D.F. (Mexico)

    2001-07-01

    The present work shows the energy saving when replacing low efficiency window type air conditioning equipment, for higher efficiency equipment, as well as the necessary parameters to identify the results obtained by the pilot projects of substitution of conventional equipment for other more efficient in the domestic sector. [Spanish] El presente trabajo muestra los ahorros de energia al sustituir equipos de aire acondicionado tipo ventana de baja eficiencia, por equipos de mayor eficiencia, asi como los parametros necesarios para identificar los resultados obtenidos, por los proyectos pilotos de sustitucion de equipos convencionales por otros mas eficientes en el sector domestico.

  20. Performance and evaluation of gas-engine-driven rooftop air conditioning equipment at the Willow Grove Naval Air Station. Final report (revised October 21, 1996)

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, P.R.; Katipamula, S.

    1996-10-01

    The performance was evaluated of a new US cooling technology that has been installed for the first time at a federal facility. The technology is a 15-ton natural gas-engine-driven rooftop air conditioning unit made by Thermo King. Two units were installed to serve the Navy Exchange at Willow Grove. The savings potential at Willow Grove is described and that in the federal sector estimated. Conditions for implementation are discussed. In summary, the new technology is generally cost-effective at sites where marginal electricity cost (per MBtu at the meter) is more than 4 times the marginal gas cost (per MBtu at the meter) and annual full-load-equivalent cooling hours exceed 2,000.

  1. Energy saving by means of air conditioning equipment replacement and the household application of thermal insulation; Ahorro de energia electrica por reemplazo de equipos de aire acondicionado y aplicacion de aislamiento termico en viviendas

    Energy Technology Data Exchange (ETDEWEB)

    Peralta Solorio, Jose Luis [Fideicomiso para el Ahorro de la Energia (Mexico)

    2005-07-15

    An extension study of the Financing Program for Energy Saving looked for the evaluation of the electric energy saving potential obtained by the replacement of air conditioning equipment and the application of thermal insulation in 30 houses of two Mexican cities with warmth climate. In a joint effort with Comision Federal de Electricidad the consumption files of the users were analyzed and field measurements of electric demand and of refrigeration were made. As a following step the change of the refrigeration necessities derived from the application of thermal insulation were evaluated as well as the energy efficiency improvement obtained by the substitution of the air conditioning equipment and the favorable results obtained by the implementation of both measures - thermal insulation and change of air conditioning equipment in a joint form. This way, as a conclusion, the optimum sequence of application of these measures is revealed. [Spanish] Un estudio extension del Programa de Financiamiento para el Ahorro de Energia Electrica busco evaluar el potencial de ahorro de energia electrica alcanzado por el reemplazo de equipos de aire acondicionado y la aplicacion de aislamiento termico en 30 viviendas de dos ciudades mexicanas con clima calido. En un esfuerzo conjunto con la Comision Federal de Electricidad se analizaron los historiales de consumo de los usuarios y se efectuaron las mediciones de campo de demanda electrica y de refrigeracion. Como paso siguiente se valoro el cambio en las necesidades de refrigeracion derivado de la aplicacion de aislamiento termico al igual que la mejora en eficiencia energetica obtenida por la sustitucion de aire acondicionado y se identificaron los resultados favorecedores arrojados por la implementacion de ambas medidas -aislamiento termico y cambio de equipo de aire acondicionado- en forma conjunta. De esta manera, como conclusion, se devela la mas optima secuencia de aplicacion de estas medidas.

  2. Energy saving: optimal use of air conditioning equipment by means of the solar control; Ahorro de energia: uso optimo de los acondicionadores de aire mediante el control solar

    Energy Technology Data Exchange (ETDEWEB)

    Mejia D, David; Morillon G, David; Rodriguez V, Luis [Universidad Nacional Autonoma de Mexico (Mexico)

    2001-09-01

    In this article the evaluation of the solar heat gains through the transparent parts of a building (houses of social interest) is presented; with the purpose of determining the heat gains through windows during summer time and under the following conditions: without solar protection, with the use of eaves, solar breakers and, finally, with the use of both elements. With the determined percentage of the diminution of heat gains, the considered potential of energy saving in air conditioning was obtained that would be available if the houses were constructed with solar control. [Spanish] En este articulo se presenta la evaluacion de las ganancias de calor solar a traves de las partes transparentes de un edificio (viviendas de interes social); con el objeto de determinar las ganancias de calor a traves de ventanas para la epoca de verano y bajo las siguientes condiciones: sin proteccion solar, con el empleo de aleros, con quiebrasoles y, finalmente, con el empleo de ambos elementos. Con el porcentaje determinado de la disminucion de ganancias de calor, se obtuvo el potencial estimado de ahorro de energia en aire acondicionado que se tendria si las viviendas se construyen con control solar.

  3. Flow in air conditioned rooms

    DEFF Research Database (Denmark)

    Nielsen, Peter V.

    1974-01-01

    Flow in air conditioned r ooms is examined by means of model experiments . The different gearnetries giving unsteady, steady three- dimensional and steady twodimensional flow are determined . Velacity profiles and temperature profiles are measured in some of the geometries. A numerical solution...... of the flow equations is demonstrated and the flow in air conditioned rooms in case of steady two dimensional flow is predi cted. Compari son with measured results is shown i n the case of small Archimedes numbers, and predictions are shown at high Archimedes numbers. A numerical prediction of f low and heat...

  4. Ventilation-air conditioning system

    International Nuclear Information System (INIS)

    Heretofore, in ventilation-air conditioning systems in a nuclear power plant, exhaust gases from each of the ventilation-air conditioning systems of a reactor building, a turbine building, a waste processing building are joined and they are released into atmosphere from the top of a high main exhaustion stack. In order to build such a high main exhaustion stack, a considerable construction cost is required and, in addition, there is a worry of lacking balance with surrounding scenery. Then, in the present invention, exhaust gases are heated by waste heat in a turbine during their introduction from the ventilation-air conditioning facility in the building of a power plant to the main exhaust stack. With such a constitution, since the exhaust gases are heated and their temperature is elevated, they uprise by natural convection when they are released from the top of the main exhaustion stack to the atmosphere. Accordingly, they are released to a level higher than the conventional case in view of the volume of the blower which sends the exhaust gases under pressure, to diffuse them to the atmosphere more sufficiently compared with a conventional case. Further, the height of the main exhaustion stack can be reduced, enabling to minimize the cost for moving the blower. (T.M.)

  5. Air conditioning system with supplemental ice storing and cooling capacity

    Science.gov (United States)

    Weng, Kuo-Lianq; Weng, Kuo-Liang

    1998-01-01

    The present air conditioning system with ice storing and cooling capacity can generate and store ice in its pipe assembly or in an ice storage tank particularly equipped for the system, depending on the type of the air conditioning system. The system is characterized in particular in that ice can be produced and stored in the air conditioning system whereby the time of supplying cooled air can be effectively extended with the merit that the operation cycle of the on and off of the compressor can be prolonged, extending the operation lifespan of the compressor in one aspect. In another aspect, ice production and storage in great amount can be performed in an off-peak period of the electrical power consumption and the stored ice can be utilized in the peak period of the power consumption so as to provide supplemental cooling capacity for the compressor of the air conditioning system whereby the shift of peak and off-peak power consumption can be effected with ease. The present air conditioning system can lower the installation expense for an ice-storing air conditioning system and can also be applied to an old conventional air conditioning system.

  6. Solar air-conditioning. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    Within the 3rd International Conference on solar air-conditioning in Palermo (Italy) at 30th September to 2nd October, 2009 the following lectures were held: (1) Removal of non-technological barriers to solar cooling technology across Southern European islands (Stefano Rugginenti); (2) The added economic and environmental value of solar thermal systems in microgrids with combined heat and power (Chris Marney); (3) Australian solar cooling interest group (Paul Kohlenbach); (4) Designing of a technology roadmap for solar assisted air conditioning in Austria (Hilbert Focke); (5) Solar cooling in the new context of renewable policies at European level (Raffaele Piria); (6) Prototype of a solar driven steam jet ejector chiller (Clemens Pollerberg); (7) New integrated solar air conditioning system (Joan Carlos Bruno); (8) Primary energy optimised operation of solar driven desiccant evaporative cooling systems through innovative control strategies; (9) Green chiller association (Uli Jakob); (10) Climate Well {sup registered} (Olof Hallstrom); (11) Low capacity absorption chillers for solar cooling applications (Gregor Weidner); (12) Solar cooling in residential, small scale commercial and industrial applications with adsorption technology (Walter Mittelbach); (13) French solar heating and cooling development programme based on energy performance (Daniel Mugnier); (14) Mirrox fresnel process heat collectors for industrial applications and solar cooling (Christian Zahler); (15) Modelling and analyzing solar cooling systems in polysun (Seyen Hossein Rezaei); (16) Solar cooling application in Valle Susa Italy (Sufia Jung); (17) Virtual case study on small solar cooling systems within the SolarCombi+Project (Bjoern Nienborg); (18) Design of solar cooling plants under uncertainty (Fernando Dominguez-Munoz); (19) Fast pre-design of systems using solar thermally driven chillers (Hans-Martin Henning); (20) Design of a high fraction solar heating and cooling plant in southern

  7. Air Conditioning, Heating, and Refrigeration. Competency-Based Curriculum Manual.

    Science.gov (United States)

    Gourley, Frank A., Jr.

    This manual was developed to serve as an aid to administrators and instructors involved with postsecondary air conditioning, heating, and refrigeration programs. The first of six chapters contains general information on program implementation, the curriculum design, facilities and equipment requirements, and textbooks and references. Chapter 2…

  8. Intelligent Control System of Textile Mill's Air-conditioning

    Institute of Scientific and Technical Information of China (English)

    WU Fu-zhuan; ZHAO Fang

    2009-01-01

    This paper briefly analyzes the present situation of textile mill's air-conditioning system. Since it is difficult to establish detailed math model to control a textile mill's air-conditioning system because of the influence of various factors such as the differences in seasons, regions, etc., most air-conditioning equipment can not he controlled automatically. This paper suggests utilizing multi-function data acquisition card to collect the data about the temperature and humidity of a workshop, processing the data on a PC, comparing them with the expert database, and then using the 485 serial port expanding module to output the parameters, which are used to control the inverter, so that the purpose of adjusting the temperature and humidity of the workshop is achieved.

  9. HEATING AND AIR CONDITIONING EDUCATIONAL PROGRAM.

    Science.gov (United States)

    Lennox Industries, Inc., Marshalltown, IA.

    INCREASED MOTIVATION, INCREASED INITIAL COMPREHENSION, AND INCREASED RETENTION ARE THE PRIME GOALS OF THE LENNOX HEATING AND AIR CONDITIONING EDUCATION PROGRAM. IT IS A COMPLETE PROGRAM WITH ALL THE TEACHING TOOLS REQUIRED TO PRODUCE A KNOWLEDGEABLE HEATING AND AIR-CONDITIONING INSTALLER OR SERVICE MAN. THIS INSTRUCTIONAL PROGRAM IS DESIGNED…

  10. Air Conditioning. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Long, William

    Several intermediate performance objectives and corresponding criterion measures are listed for each of seven terminal objectives for an intermediate air conditioning course. The titles of the seven terminal objectives are Refrigeration Cycle, Job Requirement Skills, Air Conditioning, Trouble Shooting, Performance Test, Shop Management, and S.I.E.…

  11. Fungal colonization of air-conditioning systems

    Directory of Open Access Journals (Sweden)

    Ljaljević-Grbić Milica

    2008-01-01

    Full Text Available Fungi have been implicated as quantitatively the most important bioaerosol component of indoor air associated with contaminated air-conditioning systems. rarely, indoor fungi may cause human infections, but more commonly allergenic responses ranging from pneumonitis to asthma-like symptoms. From all air conditioner filters analyzed, 16 fungal taxa were isolated and identified. Aspergillus fumigatus causes more lethal infections worldwide than any other mold. Air-conditioning filters that adsorb moisture and volatile organics appear to provide suitable substrates for fungal colonization. It is important to stress that fungal colonization of air-conditioning systems should not be ignored, especially in hospital environments.

  12. Refrigerating and air conditioning systems: dilemmas in the future development

    International Nuclear Information System (INIS)

    harmful influence of CFC fluids, depletion on the ozone layer and global warming of Earth. Survey on the most applied refrigerants and their potentials for harmful influence on the ozone layer and global warming. Montreal protocol and additional regulations (amendments). Measures for a phase-out of CFCs in Republic of Macedonia, projects, forming of training centers, training courses for good maintenance and servicing of refrigerating and air conditioning systems, equipment for recovery and recycling of refrigerants. The newest alternative refrigerants and their properties. Specifics in application of the new HFC fluids. Natural refrigerants: ammonia, carbon-hydrogen's, carbon-dioxide, water, air. Failing (toxicity and flammability) and advantages in their appliance. New concepts of refrigerating and air conditioning systems. Cross way in the future development of refrigerating and air conditioning systems. Crossing of opposite views and interest on the international level. Missing of strategy in Republic of Macedonia in the field of refrigeration and air conditioning. paradox in R. Macedonia: ammonia refrigerating systems go out of use. (Author)

  13. Air Conditioning Does Reduce Air Pollution Indoors

    Science.gov (United States)

    Healy, Bud

    1970-01-01

    Report of the winter meeting of the American Society of Heating, Refrigerating and Air-Conditioning Engineers. Subjects covered are--(1) title subject, (2) predictions for the human habitat in 1994, (3) fans, and (4) fire safety in buildings. (JW)

  14. Heating, ventilation and air conditioning system modelling

    Energy Technology Data Exchange (ETDEWEB)

    Whalley, R.; Abdul-Ameer, A. [British University in Dubai (United Arab Emirates)

    2011-03-15

    Heating, ventilation and air conditioning modelling methods, for large scale, spatially dispersed systems are considered. Existing techniques are discussed and proposals for the application of novel analysis approaches are outlined. The use of distributed-lumped parameter procedures enabling the incorporation of the relatively concentrated and significantly dispersed, system element characteristics, is advocated. A dynamic model for a heating, ventilation and air conditioning system comprising inlet and exhaust fans, with air recirculation, heating/cooling and filtration units is presented. Pressure, airflow and temperature predictions within the system are computed following input, disturbance changes and purging operations. The generalised modelling advancements adopted and the applicability of the model for heating, ventilation and air conditioning system simulation, re-configuration and diagnostics is emphasised. The employment of the model for automatic, multivariable controller design purposes is commented upon. (author)

  15. ALTERNATIVE TECHNOLOGIES FOR REFRIGERATION AND AIR-CONDITIONING APPLICATIONS

    Science.gov (United States)

    The report gives results of an assessment of refrigeration technologies that are alternatives to vapor compression refrigeration for use in five application categories: domestic air conditioning, commercial air conditioning, mobile air conditioning, domestic refrigeration, and co...

  16. Carbon Emissions from air-Conditioning

    Directory of Open Access Journals (Sweden)

    Rajesh Kumar

    2013-01-01

    Full Text Available This paper explores electricity consumption and carbon emissions associated with air-conditioning. The total heat load of a room fitted with air conditioner of 1.5 ton capacity has been calculated by calculating conduction and ventilation losses. Solar heat gain and internal gain were taken as the other two parameters for the total heat calculation.

  17. Air Conditioning and Refrigeration Book IV.

    Science.gov (United States)

    Eckes, William; Fulkerson, Dan

    This publication is the concluding text in a four-part curriculum for air conditioning and refrigeration. Materials in Book 4 are designed to complement theoretical and functional elements in Books 1-3. Instructional materials in this publication are written in terms of student performance using measurable objectives. The course includes six…

  18. Fundamentals of Air Conditioning and Refrigeration.

    Science.gov (United States)

    Clemons, Mark

    This set of instructional materials provides secondary and postsecondary students with a state-of-the-art curriculum for the air conditioning and refrigeration industry that includes the many changes brought by new Environmental Protection Agency (EPA) regulations. Introductory materials explain the use of this publication and provide the…

  19. Air Conditioning and Refrigeration Supplementary Units.

    Science.gov (United States)

    Winston, Del; And Others

    This document contains supplemental materials for special needs high school students intended to facilitate their mainstreaming in regular air conditioning and refrigeration courses. Teacher's materials precede the materials for students and include general notes for the instructor, additional suggestions, two references, a questionnaire on the…

  20. Air Conditioning and Refrigeration. Book Two.

    Science.gov (United States)

    Wantiez, Gary W.

    This curriculum guide (book II), along with book I, is designed to provide students with the basic skills for an occupation in air conditioning and refrigeration. Six major areas are included, each consisting of one or more units of instruction. These areas and their respective units are titled as follows: Electricity (fundamentals of electricity,…

  1. Readings in Air Conditioning and Refrigeration.

    Science.gov (United States)

    Uberto, Jeffrey A.

    Designed to encourage vocational high school students to read by offering reading materials relevant to their vocational goals, this document contains thirty-seven articles related to air conditioning and refrigeration which have been selected from trade journals, magazines, and newspapers and adapted to the students' reading capabilities. A…

  2. Air Conditioning and Refrigeration. Book One.

    Science.gov (United States)

    Wantiez, Gary W.

    Designed to provide students with the basic skills for an occupation in air conditioning and refrigeration, this curriculum guide includes seven major areas, each consisting of one or more units of instruction. These areas and their respective units are titled as follows: Orientation (history and development, and job opportunities), Safety…

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

    OpenAIRE

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

    2010-01-01

    Abstract 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...

  4. Air Conditioning System using Rankine Cycle

    Science.gov (United States)

    Nagatomo, Shigemi; Yamaguchi, Hiroichi; Hattori, Hitoshi; Futamura, Motonori

    Natural gas is used as the energy source to cope with the recent situation of increasing demand for electricity especially in summer. In this paper, the performance of a Rankine cycle air conditioning system driven by natural gas was studied. The following results were obtained : (1) Basic equations of performance, refrigerant mass flow rate and expander volume were developed by using the values of heating efficiency, regeneration efficiency, expander efficiency and compressor efficiency. (2) R134a refrigerant has been considered to be suitable for the Rankine cycle air conditioning system, compared with other refrigerants. (3)A Rankine cycle cooling system using R134a refrigerant as a single working fluid was developed. System COP of 0.47 was attained at typical operating condition.

  5. Smart Sensors Enable Smart Air Conditioning Control

    OpenAIRE

    Chin-Chi Cheng; Dasheng Lee

    2014-01-01

    In this study, mobile phones, wearable devices, temperature and human motion detectors are integrated as smart sensors for enabling smart air conditioning control. Smart sensors obtain feedback, especially occupants’ information, from mobile phones and wearable devices placed on human body. The information can be used to adjust air conditioners in advance according to humans’ intentions, in so-called intention causing control. Experimental results show that the indoor temperature can be contr...

  6. Innovative Air Conditioning and Climate Control

    Science.gov (United States)

    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.

  7. Air conditioning for data processing system areas

    Directory of Open Access Journals (Sweden)

    Hernando Camacho García

    2011-06-01

    Full Text Available The appropiate selection of air conditioners for data processing system areas requires the knowledge of the environmental desing conditions, the air conditioning systems succssfully used computer and the cooling loads to handle. This work contains information about a wide variety of systems designed for computer room applications. a complete example of calculation to determine the amount of heat to be removed for satisfactory operation, is also included.

  8. Low Energy Air Conditioning for Hot Climates

    OpenAIRE

    Almutairi, Hamad Hhn

    2012-01-01

    Fossil fuels are the major sources of electrical power generation in the world. Among all fossil fuels, oil is considered as the most sought-after fuel. The burden on countries that provide subsidized electricity produced from oil-fired power plants is noteworthy. Kuwait is a notable example of these countries. Electricity in Kuwait is heavily consumed by residential air conditioning, which comprises 60% of the total electricity generated at peak times on a hot summer day. From this perspecti...

  9. Evaporative Condensers in Comfortable Air Conditioning System

    Institute of Scientific and Technical Information of China (English)

    YIN Ying-de; ZHU Dong-sheng; DU Gui-mei; LI Yuan-xi; SUN He-jing; LIU Qing-ming

    2009-01-01

    The operating theory of an evaporative condenser was expatiated.The difference between an e-vaporative condensing refrigeration system and a general refrigeration system was analyzed.Compared with the air-cooled and the water-cooled,the virtues of energy-conservation and water-conservation of evaporative con-densers were analyzed.Some questions existing in the application of evaporative condensers were pointed out,the corresponding solving methods were analyzed accordingly,and the development trend of evaporative con-densing technique in mechanical refrigeration system field and the applied foreground of evaporative condensers in comfortable air conditioning were prospected.

  10. Thermal analysis of car air conditioning

    Science.gov (United States)

    Trzebiński, Daniel; Szczygieł, Ireneusz

    2010-10-01

    Thermodynamic analysis of car air cooler is presented in this paper. Typical refrigerator cycles are studied. The first: with uncontrolled orifice and non controlled compressor and the second one with the thermostatic controlled expansion valve and externally controlled compressor. The influence of the refrigerant decrease and the change of the air temperature which gets to exchangers on the refrigeration efficiency of the system; was analysed. Also, its effectiveness and the power required to drive the compressor were investigated. The impact of improper refrigerant charge on the performance of air conditioning systems was also checked.

  11. Refrigeration, Heating & Air Conditioning. Post Secondary Curriculum Guide.

    Science.gov (United States)

    Garrison, Joe C.; And Others

    This curriculum guide was designed for use in postsecondary refrigeration, heating and air conditioning education programs in Georgia. Its purpose is to provide for the development of entry level skills in refrigeration, heating, and air conditioning in the areas of air conditioning knowledge, theoretical structure, tool usage, diagnostic ability,…

  12. Instructional Guide for Air Conditioning and Refrigeration. V & TECC Curriculum Guide.

    Science.gov (United States)

    Duenk, Lester G.; And Others

    This trade and industrial curriculum guide is intended for use in vocational programs that prepare students to enter the air conditioning/refrigeration field. The introductory section provides a statement of philosophy, objectives, block time schedule, and recommended facilities and equipment. Following the introductory section, eighteen blocks of…

  13. Smart sensors enable smart air conditioning control.

    Science.gov (United States)

    Cheng, Chin-Chi; Lee, Dasheng

    2014-01-01

    In this study, mobile phones, wearable devices, temperature and human motion detectors are integrated as smart sensors for enabling smart air conditioning control. Smart sensors obtain feedback, especially occupants' information, from mobile phones and wearable devices placed on human body. The information can be used to adjust air conditioners in advance according to humans' intentions, in so-called intention causing control. Experimental results show that the indoor temperature can be controlled accurately with errors of less than ±0.1 °C. Rapid cool down can be achieved within 2 min to the optimized indoor capacity after occupants enter a room. It's also noted that within two-hour operation the total compressor output of the smart air conditioner is 48.4% less than that of the one using On-Off control. The smart air conditioner with wearable devices could detect the human temperature and activity during sleep to determine the sleeping state and adjusting the sleeping function flexibly. The sleeping function optimized by the smart air conditioner with wearable devices could reduce the energy consumption up to 46.9% and keep the human health. The presented smart air conditioner could provide a comfortable environment and achieve the goals of energy conservation and environmental protection. PMID:24961213

  14. Smart Sensors Enable Smart Air Conditioning Control

    Directory of Open Access Journals (Sweden)

    Chin-Chi Cheng

    2014-06-01

    Full Text Available In this study, mobile phones, wearable devices, temperature and human motion detectors are integrated as smart sensors for enabling smart air conditioning control. Smart sensors obtain feedback, especially occupants’ information, from mobile phones and wearable devices placed on human body. The information can be used to adjust air conditioners in advance according to humans’ intentions, in so-called intention causing control. Experimental results show that the indoor temperature can be controlled accurately with errors of less than ±0.1 °C. Rapid cool down can be achieved within 2 min to the optimized indoor capacity after occupants enter a room. It’s also noted that within two-hour operation the total compressor output of the smart air conditioner is 48.4% less than that of the one using On-Off control. The smart air conditioner with wearable devices could detect the human temperature and activity during sleep to determine the sleeping state and adjusting the sleeping function flexibly. The sleeping function optimized by the smart air conditioner with wearable devices could reduce the energy consumption up to 46.9% and keep the human health. The presented smart air conditioner could provide a comfortable environment and achieve the goals of energy conservation and environmental protection.

  15. Alternative non-CFC mobile air conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Mei, V.C.; Chen, F.C.; Kyle, D.M.

    1992-09-01

    Concern about the destruction of the global environment by chlorofluorocarbon (CFC) fluids has become an impetus in the search for alternative, non-CFC refrigerants and cooling methods for mobile air conditioning (MAC). While some alternative refrigerants have been identified, they are not considered a lasting solution because of their high global warming potential, which could result in their eventual phaseout. In view of this dilemma, environmentally acceptable alternative cooling methods have become important. This report, therefore, is aimed mainly at the study of alternative automotive cooling methodologies, although it briefly discusses the current status of alternative refrigerants. The alternative MACs can be divided into work-actuated and heat-actuated systems. Work-actuated systems include conventional MAC, reversed Brayton air cycle, rotary vane compressor air cycle, Stirling cycle, thermoelectric (TE) cooling, etc. Heat-actuated MACs include metal hydride cooling, adsorption cooling, ejector cooling, absorption cycle, etc. While we are better experienced with some work-actuated cycle systems, heat-actuated cycle systems have a high potential for energy savings with possible waste heat applications. In this study, each altemative cooling method is discussed for its advantages and its limits.

  16. Siamese twins. [Relationship between lighting and air conditioning systems

    Energy Technology Data Exchange (ETDEWEB)

    Bauschke, P.

    1981-01-01

    The paper investigates the connection between lighting and air-conditioning technics. For the engineer planning an air-conditioning plant it is a must to find out the heat produced by the lighting in a room and to include it in his calculation of the air-conditioning plant. This means cooling in summer and using the thermal energy of lighting for heating purposes in winter.

  17. DESIGN a solar hybrid air conditioning compressor system

    OpenAIRE

    Khalaji Assadi M.; Gilani S. I.; Jun Yen T. C.

    2016-01-01

    To develop and integrate solar hybrid system into conventional air conditioning system which provides the same cooling load with considerably less electricity demand. Solar evacuated tube and DC compressor are used for compressing the refrigerant in an air conditioning system, thus effectively reducing the air conditioning electricity consumption by up to 45%. For the flow through type selected geometry of the designed evacuated U-tube collector, a three dimensional simulation and analysis of...

  18. On the history of air conditioning; Zur Geschichte der Raumklimatechnik

    Energy Technology Data Exchange (ETDEWEB)

    Fitzner, Klaus; Finke, Ulrich [Klimakonzept Ingenieurgesellschaft, Berlin (Germany)

    2010-01-15

    The theoretical bases of indoor air conditioning originates from the time of enlightenment (Lavoisier 1792). For the first time air conditioning is applied 1836 in the House of Commons in London. Wide application begins in the USA in the 1930s, in Germany due to the war after the 1950s. Starting from 1970 there are advancements in Germany and Northern Europe, which make it possible not to only air-condition but to fulfil thermally comfortable conditions. (orig.)

  19. Quaternions and Lorentz transformations

    International Nuclear Information System (INIS)

    In the last years, it was argued by some authors that number systems with non-commutative multiplication laws can provide a deeper physical insight into many open theoretical problems. The generalization of the Lorentz group to transformations with faster-than-light speed parameters (the so-called 'extended theory of relativity') has shown itself - apart from the real existence of tachyons - to be a useful tool in order to deal, within a purely classical (i.e. relativistic but not quantum-mechanical) frame work, with antiparticles, discrete symmetries, CPT-covariance, and so on. Therefore, it seems worthwhile looking for possible connections between non-commutative number systems and 'superluminal' Lorentz transformations. In this paper, the author reviews how Lorentz transformations (both subluminal and superluminal) have been translated in quaterion language. Besides, some considerations are made on possible, further developments of the theory, according to the suggestions by the group properties of quaternionic (generalized) Lorentz transformations (QGLT). (Auth.)

  20. Lorentz Violation and Gravity

    CERN Document Server

    Bailey, Quentin G

    2009-01-01

    In the last decade, a variety of high-precision experiments have searched for miniscule violations of Lorentz symmetry. These searches are largely motivated by the possibility of uncovering experimental signatures from a fundamental unified theory. Experimental results are reported in the framework called the Standard-Model Extension (SME), which describes general Lorentz violation for each particle species in terms of its coefficients for Lorentz violation. Recently, the role of gravitational experiments in probing the SME has been explored in the literature. In this talk, I will summarize theoretical and experimental aspects of these works. I will also discuss recent lunar laser ranging and atom interferometer experiments, which place stringent constraints on gravity coefficients for Lorentz violation.

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

    Energy Technology Data Exchange (ETDEWEB)

    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 systems work, and describes a refrigerant free liquid desiccant based cooling system.

  2. 2015 German refrigeration and air conditioning meeting. Abstracts

    International Nuclear Information System (INIS)

    The volume contains the abstracts of the 2015 German refrigeration and air conditioning meeting in 5 chapters: cryo-technology, fundamentals of materials for refrigeration engineering and heat pump technology, facilities and components for the refrigeration and heat pump technology; application of refrigeration engineering; air conditioning technology and heat pump application.

  3. DEVELOPMENT OF NEURO FUZZY CONTROLLER ALGORITHM FOR AIR CONDITIONING SYSTEM

    OpenAIRE

    AMRIT KAUR; ARSHDEEP KAUR

    2012-01-01

    The paper presents the neuro-fuzzy controller algorithm for air conditioning system. Neuro-fuzzy control combines the learning capabilities of neural networks and control capabilities of fuzzy logic control. The neurofuzzy controller for air conditioning system takes two inputs from temperature and humidity sensors and controls the compressor speed. The experimental results of the developed system are also shown.

  4. DEVELOPMENT OF NEURO FUZZY CONTROLLER ALGORITHM FOR AIR CONDITIONING SYSTEM

    Directory of Open Access Journals (Sweden)

    AMRIT KAUR

    2012-04-01

    Full Text Available The paper presents the neuro-fuzzy controller algorithm for air conditioning system. Neuro-fuzzy control combines the learning capabilities of neural networks and control capabilities of fuzzy logic control. The neurofuzzy controller for air conditioning system takes two inputs from temperature and humidity sensors and controls the compressor speed. The experimental results of the developed system are also shown.

  5. Thermal Environment for Classrooms. Central System Approach to Air Conditioning.

    Science.gov (United States)

    Triechler, Walter W.

    This speech compares the air conditioning requirements of high-rise office buildings with those of large centralized school complexes. A description of one particular air conditioning system provides information about the system's arrangement, functions, performance efficiency, and cost effectiveness. (MLF)

  6. Air Conditioning and Refrigeration Program Articulation, 1981-1982.

    Science.gov (United States)

    Dallas County Community Coll. District, TX.

    Based on a survey of high school programs and courses in the Dallas County Community College District (DCCCD), this articulated program is designed to prepare students for entry-level employment in the air conditioning and refrigeration industry, including residential and commercial air conditioning and commercial refrigeration. The skills and…

  7. Mountain Plains Learning Experience Guide: Heating, Refrigeration, & Air Conditioning.

    Science.gov (United States)

    Carey, John

    This Heating, Refrigeration, and Air Conditioning course is comprised of eleven individualized units: (1) Refrigeration Tools, Materials, and Refrigerant; (2) Basic Heating and Air Conditioning; (3) Sealed System Repairs; (4) Basic Refrigeration Systems; (5) Compression Systems and Compressors; (6) Refrigeration Controls; (7) Electric Circuit…

  8. Vibration Analysis of Air Condition Unit on Subway

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2013-06-01

    Full Text Available Subway system has many merits including large passenger carrying ability, high speed, strong controllability and reliability of driving. Nevertheless, subways also have brought many disadvantages for human. In many subway systems, noisy environments are clearly observed and passengers are exposed to higher noise levels than permissible limit. This study presents a study of noise and vibration of subway air condition system, so as to grasp the vibration distribution laws of the air condition system. By the tested of noise and vibration, the researcher find the sound distribution rule of air condition is very important Based on the consequence of the testing, the acceleration of air condition has little to do with the subway speed and more to do with the vibration of fan; When the train driving on the viaduct bridge, the acceleration of air condition is biggish in 125 Hz and In 50-1000 Hz the vibration of air condition is obviously. When the train running underground line, as a result of the resonance of body, air condition’s vibration is biggish in 630 Hz and the vibration is obviously in 125-1250 Hz. With the increase of the speed, the influence of the ground’s second radiation on body vibration is enhanced. The superfine gross wool which is used to air condition can achieve good results for noise reduction. This research has higher reference for the vibration and noise reduction of the subway air condition system.

  9. Lorentz violation naturalness revisited

    CERN Document Server

    Belenchia, Alessio; Liberati, Stefano

    2016-01-01

    We revisit here the naturalness problem of Lorentz invariance violations on a simple toy model of a scalar field coupled to a fermion field via a Yukawa interaction. We first review some well-known results concerning the low-energy percolation of Lorentz violation from high energies, presenting some details of the analysis not explicitly discussed in the literature and discussing some previously unnoticed subtleties. We then show how a separation between the scale of validity of the effective field theory and that one of Lorentz invariance violations can hinder this low-energy percolation. While such protection mechanism was previously considered in the literature, we provide here a simple illustration of how it works and of its general features. Finally, we consider a case in which dissipation is present, showing that the dissipative behaviour does not percolate generically to lower mass dimension operators albeit dispersion does. Moreover, we show that a scale separation can protect from unsuppressed low-en...

  10. Sea Water Air Conditioning [SWAC]: A Cost Effective Alternative

    Directory of Open Access Journals (Sweden)

    A.F. Elsafty

    2009-09-01

    Full Text Available The energy demand for air conditioning is quite extensive due to the hot and humid summer climate in Egypt. The rapid increase in non industrial electricity consumption is due to the rural electrification and the presence of many buildings that are air conditioned in summer using electricity. Deep cold ocean and sea water is a valuable natural resource that can be used for energy production, cooling, desalination, aquaculture and agriculture. The most economic viable use of this deep water is to air-condition buildings through a sea water air conditioning system (SWAC. This study reports the results of a technical and economical assessment of the potential use of sea water air conditioning (SWAC other than the conventional vapor compression systems used to air condition hotels at a new tourists resort called “Sahl-Hasheesh”,18km south of Hurghada, Egypt. This study analyzed and sized the major components of the Sea water Air Conditioning (SWAC system, determined the operational performance, and estimated the probable costs. The economic analysis was based on two different methods, the simple pay back and the net present value (NPV method. The results showed that the SWAC system is the preferred option for its short payback period as well as the minimum net present value when being applied at Sahl-Hasheesh area. Large energy savings approaching 80% compared to the conventional ones. This is in addition to the low green house gas emissions.

  11. Decoupling dehumidification and cooling for energy saving and desirable space air conditions in hot and humid Hong Kong

    International Nuclear Information System (INIS)

    Highlights: ► The combined use of dedicated ventilation and dry cooling (DCDV) system was investigated. ► Investigations were based actual equipment performance data and realistic building and system characteristics. ► DCDV system could save 54% of the annual energy use for air-conditioning. ► DCDV system could better achieve the desired space air conditions. ► DCDV system could decouple dehumidification and cooling. - Abstract: The combined use of dedicated outdoor air ventilation (DV) and dry cooling (DC) air-conditioning system to decouple sensible and latent cooling for desirable space air conditions, better indoor air quality, and energy efficiency is proposed for hot and humid climates like Hong Kong. In this study, the performance and energy saving potential of DCDV system in comparison to conventional systems (constant air volume (CAV) system with and without reheat) for air conditioning of a typical office building in Hong Kong are evaluated. Through hour-by-hour simulations, using actual equipment performance data and realistic building and system characteristics, the cooling load profile, resultant indoor air conditions, condensation at the DC coil, and energy consumptions are calculated and analyzed. The results indicate that with the use of DCDV system, the desirable indoor conditions could be achieved and the annual energy use could be reduced by 54% over CAV system with reheat. The condensate-free characteristic at the DC coil to reduce risk of catching disease could also be realized.

  12. DESIGN a solar hybrid air conditioning compressor system

    Directory of Open Access Journals (Sweden)

    Khalaji Assadi M.

    2016-01-01

    Full Text Available To develop and integrate solar hybrid system into conventional air conditioning system which provides the same cooling load with considerably less electricity demand. Solar evacuated tube and DC compressor are used for compressing the refrigerant in an air conditioning system, thus effectively reducing the air conditioning electricity consumption by up to 45%. For the flow through type selected geometry of the designed evacuated U-tube collector, a three dimensional simulation and analysis of the thermal performance was done, using the solar ray-tracing model provided by the ANSYS-FLUENT software.

  13. Simulation technology for refrigeration and air conditioning appliances

    Institute of Scientific and Technical Information of China (English)

    DING Guoliang

    2006-01-01

    Simulation technology has been widely used for performance prediction and optimal design of refrigeration and air conditioning appliances. A brief history of simulation technology for refrigeration and air conditioning appliances is reviewed. The models for evaporator, condenser, compressor, capillary tube and thermal insulation layer are summarized, and a fast calculation method for thermodynamic properties of refrigerant is introduced in this paper. The model-based intelligent simulation technology and the simulation technology based on graph theory are also illustrated. Finally, an updated trend of simulation technology development for refrigeration and air conditioning appliances is discussed.

  14. Geothermal as a heat sink application for raising air conditioning efficency

    Science.gov (United States)

    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

  15. PROSPECTS FOR THE DEVELOPMENT OF TECHNOLOGY AIR CONDITIONING

    Directory of Open Access Journals (Sweden)

    O. V. Chernyshova

    2008-03-01

    Full Text Available In the article the evaporation cooling and spray (aqueous and air-to-water types of the air-conditioning systems are considered, their merits and demerits are analyzed; the new scheme of a conditioner is offered.

  16. 2014 German refrigeration and air conditioning meeting. Proceedings

    International Nuclear Information System (INIS)

    The proceedings of the 2014 German refrigeration and air conditioning meeting contain contributions on the following topics: cryotechnology, fundamentals and materials for the refrigeration and heat pump technology, devices and components for the refrigeration and heat pump technology, applications of refrigeration technologies, air conditioning technology and heat pump applications, cryotechnology in biology and medicine, heat transfer and ventilation, guidelines and legal topics, refrigerant fluid - oil mixtures, control and surveillance, simulation and control, ambient air.

  17. RESOURCES MECHANISM OF REFRIGERATION AND AIR CONDITIONING TECHNOLOGY

    OpenAIRE

    Eugenio A. Ermac, Ph.D.

    2016-01-01

    This paper is an extensive analytical addendum of the research data utilized in a published research. This study determined the resources mechanism in refrigeration and air conditioning technology at CTU systems. It was conducted for the purpose of providing the administrators and its constituents the basic information on the present status of the refrigeration and air conditioning technology of the Cebu Technological University System Further, it can be inferred that insufficiency is paralle...

  18. Computer Model to Estimate Reliability Engineering for Air Conditioning Systems

    International Nuclear Information System (INIS)

    Reliability engineering is used to predict the performance and optimize design and maintenance of air conditioning systems. Air conditioning systems are expose to a number of failures. The failures of an air conditioner such as turn on, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply and loss of air flow entirely can be due to a variety of problems with one or more components of an air conditioner or air conditioning system. Forecasting for system failure rates are very important for maintenance. This paper focused on the reliability of the air conditioning systems. Statistical distributions that were commonly applied in reliability settings: the standard (2 parameter) Weibull and Gamma distributions. After distributions parameters had been estimated, reliability estimations and predictions were used for evaluations. To evaluate good operating condition in a building, the reliability of the air conditioning system that supplies conditioned air to the several The company's departments. This air conditioning system is divided into two, namely the main chilled water system and the ten air handling systems that serves the ten departments. In a chilled-water system the air conditioner cools water down to 40-45 degree F (4-7 degree C). The chilled water is distributed throughout the building in a piping system and connected to air condition cooling units wherever needed. Data analysis has been done with support a computer aided reliability software, this is due to the Weibull and Gamma distributions indicated that the reliability for the systems equal to 86.012% and 77.7% respectively. A comparison between the two important families of distribution functions, namely, the Weibull and Gamma families was studied. It was found that Weibull method performed for decision making.

  19. 2013 German refrigeration and air conditioning meeting. Proceedings

    International Nuclear Information System (INIS)

    These proceedings cover the following main topics: cryoengineering - superconduction / energy storage; cryoapplications in biology and medicine; metrology; adsorption processes; condensation/evaporation; working fluids / simulation; ice production; plants and compressors; expansion and ejectors or recooling; use of cooling (passenger car air conditioning, supermarket); refrigerants; plant efficiency; emissions and legislation; air conditioning and use of heat pumps; air quality and control; building technology and block-type thermal power stations.

  20. Performance and evaluation of desiccant based air conditioning system.

    Directory of Open Access Journals (Sweden)

    Gaurav S. Wani

    2014-12-01

    Full Text Available This Project work presents study and experimental analysis of Desiccant based air conditioning system.The main purpose of this project is to increase the efficency of air conditioning system.In the convenstional air conditioning system cooling coli has two load latent load and sensible load. Cooling has to cool the air and simultaneously to dehumidify it.It increases load on cooling coil and affects performance to the system. To increase the efficiency the air conditioning system desiccant materials are used at the inlet of the air conditioning test rig. Desiccant materials attract moisture based on differences in vapor pressure. Due to their enormous affinity to absorb water and considerable ability to hold water. Due to use of desiccant material load on the cooling coil reduces since moisture is absorbed by desiccant; cooling coil has to take only sensible load. Analysis is done using different desiccant materials and based on the observation, power consumption before and after desiccant is calculated. From this conclusion is made that desiccant material improves the efficiency of air conditioning test rig

  1. Lorentz Contracted Proton

    OpenAIRE

    Bedoya Fierro, D.; Kelkar, N.(Dept. de Fisica, Universidad de los Andes, Cra. 1E No. 18A-10, Santafe de Bogota, Colombia); Nowakowski, M.

    2014-01-01

    The proton charge and magnetization density distributions can be related to the well known Sachs electromagnetic form factors $G_{E,M}({\\bm q}^{2})$ through Fourier transforms, only in the Breit frame. The Breit frame however moves with relativistic velocities in the Lab and a Lorentz boost must be applied to the form factors before extracting the static properties of the proton from the corresponding densities. Apart from this, the Fourier transform relating the densities and form factors is...

  2. Monitoring and analysis of an absorption air-conditioning system

    Energy Technology Data Exchange (ETDEWEB)

    Perez de Vinaspre, M.; Bourouis, M.; Coronas, A. [Centro de Innovacion Tecnologica en Revalorizacion Energetica y Refrigeracion, Tarragona (Spain); Garcia, A.; Soto, V.; Pinazo, J.M. [E.T.S. Ingenieros Industriales, Valencia (Spain)

    2004-09-01

    In the last few years, high-energy consumption due to air-conditioning has led to a growing interest in the efficient use of energy in buildings. Although simulation programs have always been the main tools for analyzing energy in buildings, the reliability of their results is often compromised by a lack of certainty to reflect real conditions. The aim of this work is to monitorize and analyze the thermal behavior of an absorption-based air-conditioning installation of a university building in Tarragona, Spain. The existing monitoring system of the installation has been improved by implementing additional sensors and flow meters. The data has been stored during summer 2002 and used to assess the energy balance of the air-conditioning installation and the operational regime of the absorption chiller. [Author].

  3. Energy consumption in air-conditioning; Improvement and Reduction

    Directory of Open Access Journals (Sweden)

    Yacoub Yousef Ahmad Alotaibi

    2015-06-01

    Full Text Available Anew technique to reduce latent heat to improve energy consumption in air-conditioning is by using Desiccant . The aim of dehumidification process is to remove the water vapor from the processed air to liquid desiccants. Dehumidification is considered as a key feature of HVAC systems for thermal comfort. Chemical dehumidification is remove the water vapour from the air by transferring it towards a desiccant material (adsorption or absorption. Results illustrate that the application of liquid desiccant in air conditioning can improve indoor air quality, reduce energy consumption and bring environmentally friendly products, also. Lewis number increased rapidly with the increase of solution concentration Therefore liquid desiccant air conditioning systems are drawing more and more attention in recent years.

  4. A RADIANT AIR-CONDITIONING SYSTEM USING SOLAR-DRIVEN

    Directory of Open Access Journals (Sweden)

    S. A. ABDALLA

    2006-12-01

    Full Text Available Every air-conditioning system needs some fresh air to provide adequate ventilation air required to remove moisture, gases like ammonia and hydrogen sulphide, disease organisms, and heat from occupied spaces. However, natural ventilation is difficult to control because urban areas outside air is often polluted and cannot be supplied to inner spaces before being filtered. Besides the high electrical demand of refrigerant compression units used by most air-conditioning systems, and fans used to transport the cool air through the thermal distribution system draw a significant amount of electrical energy in comparison with electrical energy used by the building thermal conditioning systems. Part of this electricity heats the cooled air; thereby add to the internal thermal cooling peak load. In addition, refrigerant compression has both direct and indirect negative effects on the environment on both local and global scales. In seeking for innovative air-conditioning systems that maintain and improve indoor air quality under potentially more demanding performance criteria without increasing environmental impact, this paper presents radiant air-conditioning system which uses a solar-driven liquid desiccant evaporative cooler. The paper describes the proposed solar-driven liquid desiccant evaporative cooling system and the method used for investigating its performance in providing cold water for a radiant air-conditioning system in Khartoum (Central Sudan. The results of the investigation show that the system can operate in humid as well as dry climates and that employing such a system reduces air-conditioning peak electrical demands as compared to vapour compression systems.

  5. Lorentz Transformation and General Covariance Principle

    CERN Document Server

    Kleyn, Aleks

    2008-01-01

    I tell about different mathematical tool that is important in general relativity. The text of the book includes definition of geometrical object, concept of reference frame, geometry of metric-affinne manifold. Using this concept I learn few physical applications: dynamics and Lorentz transformation in gravitational fields, Doppler shift. A reference frame in event space is a smooth field of orthonormal bases. Every reference frame is equipped by anholonomic coordinates. Using anholonomic coordinates allows to find out relative speed of two observers and appropriate Lorentz transformation. Synchronization of a reference frame is an anholonomic time coordinate. Simple calculations show how synchronization influences time measurement in the vicinity of the Earth. Measurement of Doppler shift from the star orbiting the black hole helps to determine mass of the black hole. We call a manifold with torsion and nonmetricity the metric\\hyph affine manifold. The nonmetricity leads to a difference between the auto para...

  6. Applicability of sewage heat pump air-conditioning system

    Institute of Scientific and Technical Information of China (English)

    陈金华; 刘猛; 刘勇; 靳鸣; 陈洁

    2009-01-01

    A sewage heat pump system and its application based on a project in Chongqing,China,were discussed. Based on the sewage conditions,a feasibility analysis of the sewage heat pump air conditioning system was conducted. The theoretical and quantitative calculations indicate that sewage flux in the city sewage main pipe in the project can satisfy heat exchange requirements,and taking water from the pipes has relatively small influence on the pipe net in summer and winter. The sewage heat pump air-conditioning system can save 21.5% operating cost in one year,which is energy efficient and environmentally friendly.

  7. Breakthrough for greener air-conditioning in cars

    International Nuclear Information System (INIS)

    Alter more than a decade of research and development work at SINTEF and NTNU, a patented CO2-based car air-conditioning system is now being adopted by the automotive industry. The Japanese company Denso Corporation has acquired a licence for the use of the CO2-technology in air conditioning and heat pump systems for cars. The new system offers improved energy efficiency, eliminates the emission of greenhouse gas refrigerants, and can be operated in the heat-pump mode for rapid heating in the winter season. (author)

  8. Modern Tests of Lorentz Invariance

    Directory of Open Access Journals (Sweden)

    Mattingly David

    2005-09-01

    Full Text Available Motivated by ideas about quantum gravity, a tremendous amount of effort over the past decade has gone into testing Lorentz invariance in various regimes. This review summarizes both the theoretical frameworks for tests of Lorentz invariance and experimental advances that have made new high precision tests possible. The current constraints on Lorentz violating effects from both terrestrial experiments and astrophysical observations are presented.

  9. Advanced Print Reading. Heating, Ventilation and Air Conditioning.

    Science.gov (United States)

    Oregon State Dept. of Education, Salem.

    This is a workbook for students learning advanced blueprint reading for heating, ventilation, and air conditioning applications. The workbook contains eight units covering the following material: architectural working drawings; architectural symbols and dimensions; basic architectural electrical symbols; wiring symbols; basic piping symbols;…

  10. Solar air conditioning researches and demonstrations in China

    Institute of Scientific and Technical Information of China (English)

    Wang Ruzhu

    2009-01-01

    This paper mainly shows the demonstration of solar air conditioning systems in China, which includes LiBr-H2O absorption cooling, silica gel-water adsorption chiller, desiccant cooling and hybrid integrated energy systems for buildings. The match of solar collector types and chiller types have been discussed and suggested.

  11. Energy performance of supermarket refrigeration and air conditioning integrated systems

    OpenAIRE

    Cecchinato, Luca; Corradi, Marco; Minetto, Silvia

    2008-01-01

    Abstract The electricity consumption for air conditioning and refrigerated cases in large supermarkets represents a substantial share of the total electricity consumption. The energy efficiency of supermarkets can be improved by optimising components design, recovering thermal and refrigerating energy, adopting innovative technology solutions, integrating the HVAC system with medium temperature and low temperature refrigeration plants and, finally, reducing thermal loads on refrige...

  12. State Skill Standards: Heating, Ventilation, Air Conditioning, and Refrigeration

    Science.gov (United States)

    Ball, Larry; Soukup, Dennis

    2006-01-01

    The Department of Education has undertaken an ambitious effort to develop statewide career and technical education skill standards. The standards in this document are for Heating, Ventilation, Air Conditioning and Refrigeration (HVAC&R) programs and are designed to clearly state what the student should know and be able to do upon completion of an…

  13. Human requirements in future air-conditioned environments

    DEFF Research Database (Denmark)

    Fanger, Povl Ole

    2002-01-01

    Air-conditioning of buildings has played a very positive role for economic development in warm climates. Still its image is globally mixed. Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from SBS symptoms, even...

  14. Human requirements in future air-conditioned environments

    DEFF Research Database (Denmark)

    Fanger, Povl Ole

    1999-01-01

    Although air-conditioning has played a positive role for economic development in warm climates, its image is globally mixed. Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from Sick Building Syndrome (SBS) symptoms...

  15. Human requirements in future air-conditioned environments

    DEFF Research Database (Denmark)

    Fanger, Povl Ole

    2001-01-01

    Although air-conditioning has played a positive role for economic development in warm climates, its image is globally mixed. Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from Sick Building Syndrome (SBS) symptoms...

  16. Design of energy efficient ventilation and air-conditioning systems

    CERN Document Server

    Seppänen, Olli; Bertilsson, Thore; Maripuu, Mari-Liis; Lamy, Hervé; Vanden Borre, Alex

    2012-01-01

    This guidebook covers numerous system components of ventilation and air-conditioning systems and shows how they can be improved by applying the latest technology products. Special attention is paid to details, which are often overlooked in the daily design practice, resulting in poor performance of high quality products once they are installed in the building system.

  17. Step response and frequency response of an air conditioning system

    NARCIS (Netherlands)

    Crommelin, R.D.; Jackman, P.J.

    1978-01-01

    A system of induction units of an existing air conditioning system has been analyzed with respect to its dynamic properties. Time constants were calculated and measured by analogue models. Comparison with measurements at the installation itself showed a reasonable agreement. Frequency responses were

  18. Non-CFC air conditioning for transit buses

    Energy Technology Data Exchange (ETDEWEB)

    Pesaran, A.A.; Parent, Y.O.; Bharathan, D.

    1992-11-01

    In the United Sates, more than 80% of transit city buses are air conditioned. Vapor compression refrigeration systems are standard for air conditioning buses and account for up to 25% of fuel consumption in the cooling season. Vapor compression devices use chlorofluorocarbons (CFCs), chemicals that contributes to Earths`s ozone depletion and to global warming. Currently, evaporative cooling is an economical alternative to CFC vapor compression refrigeration for air conditioning buses. It does not use CFCs but is restricted in use to arid climates. This limitation can be eliminated by dehumidifying the supply air using desiccants. We studied desiccant systems for cooling transit buses and found that the use of a desiccant-assisted evaporative cooling system is feasible and can deliver the required cooling. The weight and the size of the desiccant system though larger than vapor compression systems, can be easily accommodated within a bus. Fuel consumption for naming desiccant systems was about 70% less than CFC refrigeration system, resulting in payback periods of less than 2.5 years under most circumstances. This preliminary study indicated that desiccant systems combined with evaporative cooling is a CFC-free option to vapor compression refrigeration for air conditioning of transit buses. The concept is ready to be tested in a fun prototype scale in a commercial bus.

  19. Non-CFC air conditioning for transit buses

    Energy Technology Data Exchange (ETDEWEB)

    Pesaran, A.A.; Parent, Y.O.; Bharathan, D.

    1992-11-01

    In the United Sates, more than 80% of transit city buses are air conditioned. Vapor compression refrigeration systems are standard for air conditioning buses and account for up to 25% of fuel consumption in the cooling season. Vapor compression devices use chlorofluorocarbons (CFCs), chemicals that contributes to Earths's ozone depletion and to global warming. Currently, evaporative cooling is an economical alternative to CFC vapor compression refrigeration for air conditioning buses. It does not use CFCs but is restricted in use to arid climates. This limitation can be eliminated by dehumidifying the supply air using desiccants. We studied desiccant systems for cooling transit buses and found that the use of a desiccant-assisted evaporative cooling system is feasible and can deliver the required cooling. The weight and the size of the desiccant system though larger than vapor compression systems, can be easily accommodated within a bus. Fuel consumption for naming desiccant systems was about 70% less than CFC refrigeration system, resulting in payback periods of less than 2.5 years under most circumstances. This preliminary study indicated that desiccant systems combined with evaporative cooling is a CFC-free option to vapor compression refrigeration for air conditioning of transit buses. The concept is ready to be tested in a fun prototype scale in a commercial bus.

  20. Heating, Air-Conditioning, and Refrigeration Technician. National Skill Standards.

    Science.gov (United States)

    Vocational Technical Education Consortium of States, Decatur, GA.

    This guide contains information on the knowledge and skills identified by industry as essential to the job performance of heating, air-conditioning, and refrigeration technicians. It is intended to assist training providers in public and private institutions, as well as in industry, to develop and implement training that will provide workers with…

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

    Science.gov (United States)

    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…

  2. Inspection and auditing of air-conditioning facilities in Europe - A new efficiency target

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, Maxime; Adnot, Jerome [Ecole des Mines de Paris (France).Center for Energy and Processes

    2005-07-01

    In coming years, the European stock of air conditioning equipment in use will partly become obsolete. In 2012, 50% of the Air-Conditioning market of EU-15 will be used to replace existing obsolete equipment (more than 15 years of operation) so that an opportunity exists to introduce higher efficiency systems. Indeed, the EPBD (European Energy Performance of Building Directive) introduced the technical obsolescence as a possible cause of replacement in addition to simple failure. A regular inspection of buildings equipped with Air-Conditioning systems is now obligatory. First of all, the paper details the EPBD Article 9 (European Parliament 2003) on the inspection and explains its scope, objectives and stakes. Indeed, too costly or too frequent inspections could create market distortions by leading building owners to prefer low capacity equipment that can be less energy-efficient. The paper focuses on the definition and the relevance of the 12-kilowatt limit and then on the type of installations included in the scope of that inspection. Despite problems, stakes are important in terms of energy savings because there is a strong link between the inspection and the audit, which is the first step toward Energy-Efficiency. After that first phase, we model inspection and audit markets in the European Union, especially in the five biggest markets. The model shows that the Air-Conditioning market will increase a lot in the future and that present stock will become obsolete very soon. Inspection and audit markets are therefore enormous and Member States have to prepare the transposition as quickly as possible. Last of all, standardisation is one way to accelerate the adoption process for this regulation. The draft standard (CEN 2004) developed by CEN (European Committee of Standardization) is a step in that direction but seems to be imperfect and several questions remain. However, facing with the quantity of buildings and the lack of time, several Member States could adopt

  3. Automobile air-conditioning its energy and environmental impact; La climatisation automobile impact energetique et environnemental

    Energy Technology Data Exchange (ETDEWEB)

    Barbusse, St.; Gagnepain, L.

    2003-05-01

    Over the last three decades, automobile manufacturers have made a lot of progress in specific fuel consumption and engine emissions of pollutants. Yet the impact of these improvements on vehicle consumption has been limited by increased dynamic performances (maxi-mum speed, torque), increased safety (power steering and power brakes) and increased comfort (noise and vibration reduction, electric windows and thermal comfort). Because of this, the real CO{sub 2}-emission levels in vehicles is still high in a context where road transport is a major factor in the balance sheet of greenhouse gas emissions, thus in complying with the inter-national climate convention. Although European, Japanese and Korean manufacturers signed an important agreement with the European Commission for voluntarily reducing CO{sub 2} emissions from their vehicles, with a weighted average emission goal by sales of 140 grams per km on the MVEG approval cycle by 2008, it has to be noted that the European procedures for measuring fuel consumption and CO{sub 2} emissions do not take accessories into account, especially air-condition ng (A/C). The big dissemination of this equipment recognized as a big energy consumer and as using a refrigerant with a high global warming potential ed ADEME to implement a set of assessments of A/C's energy and environmental impact. In particular these assessments include studies of vehicle equipment rates, analyses of impact on fuel consumption as well as regulated pollutant emissions in the exhaust, a characterization of the refrigerant leakage levels and an estimate of greenhouse gas emissions for all air-conditioned vehicles. This leaflet summarizes the results of these actions. All of these studies and additional data are presented in greater detail in the document,-'Automobile Air-conditioning' (ADEME reference no. 4985). (author)

  4. Greenhouse effect: effects on refrigerating and air conditioning industries; Effet de serre: impacts sur les professions du froid et de la climatisation

    Energy Technology Data Exchange (ETDEWEB)

    Le Boru, B. [Association Francaise de Froid, Alliance Froid Climatisation Environnement, 75 - Paris (France)

    1997-12-31

    The various factors (refrigerant characteristics, design and operating performance, insulation type, etc.) involved in greenhouse gas emission from refrigerating and air conditioning equipment are listed with the potential actions that may be taken at the different stages of equipment design, engineering, installation, operation, maintenance and dismantling, in order to reduce pollutant emissions

  5. Solar air-conditioning-active, hybrid and passive

    Energy Technology Data Exchange (ETDEWEB)

    Yellott, J. I.

    1981-04-01

    After a discussion of summer air conditioning requirements in the United States, active, hybrid, and passive cooling systems are defined. Active processes and systems include absorption, Rankine cycle, and a small variety of miscellaneous systems. The hybrid solar cooling and dehumidification technology of desiccation is covered as well as evaporative cooling. The passive solar cooling processes covered include convective, radiative and evaporative cooling. Federal and state involvement in solar cooling is then discussed. (LEW)

  6. Alternative air-conditioning with the use of solar energy

    International Nuclear Information System (INIS)

    The paper concerns the investigation of the alternative air condition systems on the basis of the open absorbtion cycle with the use of solar energy as a heat source. Schematic solution of systems has been carried. The design analysis of working characteristics was performed for a wide rang of initial parameters (teperature and humidity of ambient air, the type and concentration of liquid sorbents, etc.) and construction features of heat and mass transfer.(Author)

  7. Novel Reduced GWP Refrigerant Compositions for Stationary Air Conditioning

    OpenAIRE

    Leck, Thomas J.; Naicker, Pavan K.; Hughes, Joshua; Hydutsky, Bianca

    2014-01-01

    The current fluids most widely used for small and mid-sized air conditioning systems globally are R-410A and R-22. While these fluids have many positive attributes for cooling, they are the subject of valid criticisms regarding their high direct global warming potential (GWP) and, in the case of R-22, ozone depletion potential (ODP) also. In the interest of improved environmental sustainability, a new class of refrigerant molecule has been developed, the hydrofluoroolefin, or HFO. While the v...

  8. Hybrid liquid desiccant air-conditioning system: Experiments and simulations

    International Nuclear Information System (INIS)

    This study focuses on a hybrid liquid desiccant air-conditioning system consisting of a conventional liquid desiccant system and a vapour compression heat pump. The hybrid liquid desiccant air-conditioning system is expected to enhance the system efficiency of a conventional liquid desiccant system. In this study, the liquid desiccant is aqueous solution of lithium chloride and the refrigerant of the vapour compression heat pump is R407C. The main feature of this system is that the absorber and regenerator are integrated with the evaporator and condenser respectively. The performance evaluation test is conducted to obtain the primary data. Additionally, the improvement method for the system efficiency is discussed by the mathematical calculations. As a result, the system can dehumidify 5.9 g/kg(DA) under the conditions of summer in Tokyo, Japan. Then, the calculation results show that COPs can become higher by improving the compressor isentropic efficiency and the temperature efficiency of solution heat exchanger. - Highlights: → We focus on a hybrid liquid desiccant air-conditioning system. → The feature of the system is that the absorber is integrated with the evaporator. → We develop a mathematical model considering heat and mass transfer in the absorber. → The simulation and experiment are carried out to reveal the system performance. → COP becomes higher by improving the compressor and the solution heat exchanger.

  9. TEWI Evaluation for Household Refrigeration and Air-Conditioning Systems

    Science.gov (United States)

    Sobue, Atsushi; Watanabe, Koichi

    In the present study, we have quantitatively evaluated the global warming impact by household refrigerator and air-conditioning systems on the basis of reliable TEWI information. In TEWI evaluation of household refrigerators, the percentage of the impact by refrigerant released to the atmosphere (direct effect) is less than 18.6% in TEWI. In case of room air-conditioners, however, the percentage of direct effect is less than 5.4% in TEWI. Therefore, it was confirmed that impact by CO2 released as a result of the energy consumed to drive the refrigeration or air-conditioning systems throughout their lifetime (indirect effect) is far larger than direct effect by the entire system. A reduction of indirect effect by energy saving is the most effective measure in reducing the global warming impact by refrigeration and air-conditioning systems, For a realization of the energy saving, not only the advanced improvement in energy efficiency by household appliance manufacturers but also the improvement of consumer's mind in selecting the systems and a way of using are concluded important.

  10. Indoor air quality investigation at air-conditioned and non-air-conditioned markets in Hong Kong

    International Nuclear Information System (INIS)

    To characterize indoor air quality at the markets in Hong Kong, three non-air-conditioned and two air-conditioned markets were selected for this study. The indoor air pollutants measured included PM10 (particulate matters with aerodynamic diameter less than 10 μm), total bacteria count (TBC), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO2). The indoor and outdoor concentrations of these target air pollutants at these markets were measured and compared. The effects of air conditioning, temperature/relative humidity variation and different stalls on the indoor air quality were also investigated. The results indicated that all of the average indoor concentrations of PM10, TBC, CO and NO2 at the markets were below the Hong Kong Indoor Air Quality Objectives (HKIAQO) standards with a few exceptions for PM10 and TBC. The elevated PM10 concentrations at Hung Hom, Ngau Tau Kok and Wan Chai markets were probably due to the air filtration of outdoor airborne particulates emitted from vehicular exhaust, whereas high concentrations of airborne bacteria at Sai Ying Pun and Tin Shing markets were linked to the use of air conditioning. Correlation analysis demonstrated that indoor bacteria concentrations were correlated with temperature and relative humidity. The operation of air conditioning did not significantly reduce the levels of air pollutants at the markets. However, the higher indoor/outdoor ratios demonstrated that the operation of air conditioning had influence on the levels of bacteria at the markets. It was found that average PM10 concentration at poultry stalls was higher than the HKIAQO standard of 180 μg/m3, and was over two times that measured at vegetable, fish and meat stalls. Furthermore, the concentration of airborne bacteria at the poultry stalls was as high as 1031 CFU/m3, which was above the HKIAQO standard of 1000 CFU/m3. The bacteria levels at other three stalls were all below the HKIAQO standard. Statistical

  11. Containment vessel, its auxiliary system and plant air conditioning system of advanced thermal reactor Fugen

    International Nuclear Information System (INIS)

    The functional requirement for, the design and the construction of, and the functional test on the containment vessel, its auxiliary system, the plant air conditioning and ventilation system of the advanced thermal reactor, Fugen, are described in detail. The main specifications of the containment vessel are as follows: The type enclosed cylinder, the maximum operating pressure 1.35 kg/cm2g, the maximum operating temperature 100 deg C, the leak rate 0.4%/day, the inner diameter 36 m. The height 64 m, the volume 40,900 m3, and the material JIS G3118, SGV-49. The containment vessel is provided with an hatch of 5 m diameter for carrying equipments in two air locks, many high and low voltage cable penetrations, pipe penetrations, a transfer shoot and isolation values. The functions and the specifications of the containment vessel and its auxiliary equipments are explained. The relating auxiliary systems are composed of the containment vessel spray system, the pool facility for steam blow-down, the recirculation system for the air in the vessel, the annulus evacuation system and its pressure control devices, the pressure measuring instruments and pressure relief valves and the temperature measuring devices for the containment vessel, and the object, function, layout and installation of these systems are explained. Concerning the air conditioning system, each main building has the special subsystem, and they are introduced. The progress stage of construction works and the procedure and results of the functional test at the site are described. (Nakai, Y.)

  12. Report of study 7.3: cooling and air conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Russo, F.

    2000-07-01

    This report describes the results of the study carried out by the study group 7.3 in the triennium 1997-2000. The study was focused on industrial refrigeration and air conditioning for the large building utilising natural gas. The goal of this study, carried out in collaboration of the members of study group 7.3, was to analyse the markets of industrial refrigeration and air conditioning for large buildings to identify possibilities to increase the natural gas share in these sectors. The available technology in the two sectors of the market are described in a single section, i.e. the 'State of the art of the technology'. In this section, technical characteristics, applications, performances, new developments and others topics are discussed for absorbers, gas engines, gas turbines and fuel cells. In the 'Industrial Refrigeration' section an analysis of the present global market for the industrial sector is presented. Economics, advantages and barriers to gas units compared with the electrical units are discussed. Information on existing industrial plants, possible application options and new technology developments are described as well. The 'Air conditioning for the large building' section deals with offices, hotels, commercial buildings, hospitals and shopping centres with a cooling capacity of 350 kW or higher. It appears that the use of natural gas for cooling of large buildings has been increasing during the last decade, thanks to the greater availability of natural gas and the development of new technologies. A marketing survey of gas air-conditioning was carried out in cooperation with a group of Intergas Marketing. Based on the survey, the report describes the market position of natural gas relative to electricity. It provides the strategic prospects for further developing natural gas as a competitive option for air-conditioning of large buildings using a combination of state-of-the-art technologies. It is important to highlight

  13. Air conditioning: Low-cost autonomous air conditioning systems for bionic buildings; Klimatechnik: Bezahlbare, autarke Klimatisierung von bionischen Gebaeuden

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, H. [ARCADIS, Maastricht (Netherlands); Kutzker, A. [RUBITHERM GmbH, Hamburg (Germany)

    2005-05-01

    Termites in Africa construct buildings that are respectfully referred to as ''cathedrals'' by experts. Millions of insects inhabit these structures that are efficiently air conditioned: While the outside temperatures vary from 10 C at night to 45 C in daytime, the air inside has a constant temperature of 29 C +/- 1 C. The contribution presents a low-cost solution for human buildings. (orig.)

  14. Control strategies study of a complete solar assisted air conditioning system in an office building using TRNSYS

    OpenAIRE

    Thomas, Sébastien; Andre, Philippe

    2009-01-01

    It is now clearly assumed that solar assisted air conditioning is able to minimize environmental impact and CO2 production of buildings operation. How to reach highest energy savings is still a work in progress. In former literature, equipment control has been point out as a critical feature of energy consumption. Control becomes more and more important as system is complex. The complete simulation environment was developed in previous work, it includes the absorption chiller ...

  15. The Lorentz force and superconductivity

    OpenAIRE

    Hirsch, J. E.

    2003-01-01

    To change the velocity of an electron requires that a Lorentz force acts on it, through an electric or a magnetic field. We point out that within the conventional understanding of superconductivity electrons appear to change their velocity in the absence of Lorentz forces. This indicates a fundamental problem with the conventional theory of superconductivity. A hypothesis is proposed to resolve this difficulty. This hypothesis is consistent with the theory of hole superconductivity.

  16. Engine-driven hybrid air-conditioning system

    Institute of Scientific and Technical Information of China (English)

    Chaokui QIN; Hongmei LU; Xiong LIU; Gerhard SCHMITZ

    2009-01-01

    A hybrid air-conditioning system that com-bines an engine-driven chiller with desiccant dehumidifi-cation was configured and experimentally tested to provide reliable data for energy consumption and operation cost. The engine performance and the desiccant wheel perfor-mance were measured and a numeric model previously set up for dehumidification capacity prediction was validated. For a reference building, the results based upon measured data show that under present electricity/gas price ratio, more than 40% of operation cost can be saved by the hybrid system.

  17. Do-It-Yourself Additives Recharge Auto Air Conditioning

    Science.gov (United States)

    2010-01-01

    In planning for a return mission to the Moon, NASA aimed to improve the thermal control systems that keep astronauts comfortable and cool while inside a spacecraft. Goddard Space Flight Center awarded a Small Business Innovation Research (SBIR) contract to Mainstream Engineering Corporation, of Rockledge, Florida, to develop a chemical/mechanical heat pump. IDQ Inc., of Garland, Texas, exclusively licensed the technology and incorporates it into its line of Arctic Freeze products for automotive air conditioning applications. While working on the design, Mainstream Engineering came up with a unique liquid additive called QwikBoost to enhance the performance of the advanced heat pump design.

  18. Air Conditioning Systems from a 2nd Law Perspective

    OpenAIRE

    Luigi Marletta

    2010-01-01

    In this paper exergy analysis is used to assess the performance of the three most common air conditioning plant schemes: all-air, dual-duct and fan-coil systems. The results are presented in terms of flow diagrams to provide a clear picture of the exergy flow across the systems. The most relevant outcomes are that the air cooling and dehumidification is the process most responsible for the exergy loss and that the exergy efficiency of the overall systems is rather low; thus the quest for more...

  19. Solar desiccant air-conditioning. Practical experience regarding operation and performance

    Energy Technology Data Exchange (ETDEWEB)

    Haller, A.; Trinkl, C.; Wittmann, R.; Zoerner, W. [Ingolstadt Univ. of Applied Sciences (Germany). Kompetenzzentrum Solartechnik; Hanby, V. [De Montfort Univ., Leicester (GB). Inst. of Energy and Sustainable Development (IESD)

    2007-07-01

    The Kompetenzzentrum Solartechnik of Ingolstadt University of Applied Sciences (Centre of Excellence for Solar Engineering) investigates the renewable-only based HVAC system of a multipurpose building. The 10.000 m{sup 2} gross floor area building is part of the biggest logistic-centre in the region serving the AUDI automobile production facilities. On the one hand, the investigation is supposed to demonstrate the potential of solar-assisted cooling, on the other hand, the monitoring, financed by the Bavarian Ministry of Environmental Affairs, focuses on the total energy balance of the building and the various innovative building technologies. Next to a ground source heat pump plant for base-load heating and cooling, the building is equipped with two arrays of solar-thermal flat-plate collectors (100 m{sup 2} of Conergy, Germany, and 180 m{sup 2} of Solahart, Australia) and a desiccant air-conditioning system (DEC, WOLF Anlagen-Technik, Germany). This consists of two plants with an air flow of 8.000 m{sup 3}/h and a nominal cooling capacity of 42 kW each. One of the two plants is monitored. The plant itself is considered a black box in a first approach, i.e. all incoming and outgoing energy flows and the air condition are measured. Apart from the investigation of the performance of the solar-assisted air-conditioning system, the feasibility of DEC-operation using flat-plate collectors available on the market is investigated. (orig.)

  20. Analysis on a hybrid desiccant air-conditioning system

    International Nuclear Information System (INIS)

    Hybrid desiccant-assisted preconditioner and split cooling coil system, which combines the merits of moisture removal by desiccant and cooling coil for sensible heat removal, is a potential alternative to conventional vapor compression cooling systems. In this paper, experiments on a hybrid desiccant air-conditioning system, which is actually an integration of a rotary solid desiccant dehumidification and a vapor compression air-conditioning unit, had been carried out. It is found that, compared with the conventional VC (vapor compression) system, the hybrid desiccant cooling system economizes 37.5% electricity powers when the process air temperature and relative humidity are maintained at 30 oC, and 55% respectively. The reason why the hybrid desiccant cooling system features better performance relative to the VC system lies in the improvement brought about in the performance of the evaporator in VC unit due to desiccant dehumidification. A thermodynamic model of the hybrid desiccant system with R-22 as the refrigerant has been developed and the impact of operating parameters on the sensible heat ratio of the evaporator and the electric power saving rate has been analyzed. It is found that a majority of evaporators can operate in the dry condition even if the regeneration temperature is lower (i.e. 80 oC)

  1. Measurement of Vehicle Air Conditioning Pull-Down Period

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, John F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Huff, Shean P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moore, Larry G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); West, Brian H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-07-01

    Air conditioner usage was characterized for high heat-load summer conditions during short driving trips using a 2009 Ford Explorer and a 2009 Toyota Corolla. Vehicles were parked in the sun with windows closed to allow the cabin to become hot. Experiments were conducted by entering the instrumented vehicles in this heated condition and driving on-road with the windows up and the air conditioning set to maximum cooling, maximum fan speed and the air flow setting to recirculate cabin air rather than pull in outside humid air. The main purpose was to determine the length of time the air conditioner system would remain at or very near maximum cooling power under these severe-duty conditions. Because of the variable and somewhat uncontrolled nature of the experiments, they serve only to show that for short vehicle trips, air conditioning can remain near or at full cooling capacity for 10-minutes or significantly longer and the cabin may be uncomfortably warm during much of this time.

  2. Performance enhancement of a subcooled cold storage air conditioning system

    International Nuclear Information System (INIS)

    This article experimentally investigates the enhancement of thermal performance for an air conditioning system utilizing a cold storage unit as a subcooler. The cold storage unit is composed of an energy storage tank, liquid-side heat exchanger, suction-side heat exchanger and energy storage material (ESM), water. When the cooling load is lower than the nominal cooling capacity of the system, the cold storage unit can store extra cold energy of the system to subcool the condenser outlet refrigerant. Hence, both the cooling capacity and coefficient of performance (COP) of the system will be increased. This experiment tests the two operation modes: subcooled mode with energy storage and non-subcooled mode without energy storage. The results show that for fixed cooling loads at 3.05 kW, 3.5 kW and 3.95 kW, the COP of the subcooled mode are 16.0%, 15.6% and 14.1% higher than those of the non-subcooled mode, respectively. In the varied cooling load experiments, the COP of the subcooled cold storage air conditioning system is 15.3% higher than the conventional system.

  3. Design and Implementation of Air Conditioning System in Operating Room

    Directory of Open Access Journals (Sweden)

    Htet Htet Aung

    2014-10-01

    Full Text Available The system is air conditioning system in operating room. The main objective of the system was implemented to provide air balance and temperature necessary conditions and to control airflow system for ventilation units in operating room. The operation room can be controlled with fuzzy expert system and describes the desired outputs. Input parameters such as temperature, humidity, oxygen and particle are used and output parameters are chosen as air conditioning motor speed and exhaust motor speed. Input parameters of the system are taken into account optimal conditions based on oxygen as medium and other parameters are chosen minimum condition for operating room. The airflow control system is determined the two components: the airflow block and the thermal block for ventilation units in operating room. The mathematical modeling of each such system based on a computational procedure and to combine them together in an efficient manner. Whether it supports to the most suitable control for the system prototype was determined by simulating the operation with varying the number of personnel and duration of time. Finally, according to the combination of temperature and airflow regulations with PI controller, the results of simulation of the entire ventilation unit control system is obtained.

  4. Risk assessment for radon in an air-conditioned workplace

    International Nuclear Information System (INIS)

    The International Commission on Radiological Protection (ICRP) has proposed a conversion of 5mSv/WLM for risk assessment from workplace exposure to radon progeny. Currently the new ICRP Respiratory Tract Model leads to dose conversion factors (DCF) that are higher by at least a factor of 2.5 and the ICRP Model has not been recommended for assessment of risk for inhalation of radon progeny. However the model can he used to investigate the dependency of the DCF values on the atmospheric conditions. This paper describes measurements made using wire screen diffusion batteries of the radon progeny activity size distributions in the air-conditioned basement of a scientific laboratory. The results show that during work hours with the air-conditioning operating the average radon equilibrium factor was 0.11 while the average unattached fraction was ∼28%. The average radon progeny-based DCF values were found to be more than a factor of two greater than the conversion convention. Also it was found that a DCF value derived in terms of radon exposure (Bq m-3 h) had a range of a factor of 6 over the two week period of the measurements, suggesting that radon levels are not an adequate indicator of inhalation risk in these circumstances. 10 refs., 1 tab., 4 figs

  5. Classification and terms of evaporative air conditioning technology%蒸发冷却空调技术分类及术语探讨

    Institute of Scientific and Technical Information of China (English)

    黄翔; 夏青; 孙铁柱

    2012-01-01

    提出了蒸发冷却空调术语标准化的基础性框架,按照技术形式将蒸发冷却空调技术分为直接蒸发冷却空调技术、间接蒸发冷却空调技术、间接-直接蒸发冷却复合空调技术及蒸发冷却-机械制冷联合空调技术;按照产出介质(获得冷量)形式分为:风侧蒸发冷却空调技术和水侧蒸发冷却空调技术,并结合相关机组设备探讨了这些术语的定义,以图文形式介绍了各种蒸发冷却技术的工作原理.%Puts forward the basic framework for standardization of evaporative air conditioning terms. According to technical forms, the evaporative air conditioning technology is divided into direct evaporative air conditioning technology, indirect evaporative air conditioning technology, indirect-direct complex evaporative air conditioning technology and evaporative-cooling combined with mechanical-refrigeration air conditioning technology. In accordance with the forms of the output medium (cooling quantity obtained), it is divided into air side evaporative air conditioning technology and water side evaporative air conditioning technology. In the light of relevant unit equipment, discusses the definition of these terms. Presents the operating principles of various evaporative air conditioning technologies with charts and words.

  6. Energy performance assessment on central air-conditioning system of commercial building:A case study in China

    Institute of Scientific and Technical Information of China (English)

    周璇; 练斯甄; 闫军威; 康英姿

    2015-01-01

    Energy performance assessment on central air-conditioning system is essential to optimize operating, reduce operating costs, improve indoor environmental quality, and determine whether the retrofitting of the equipment is necessary. But it is difficult to evaluate it reasonably and comprehensively due to its complexity.A “holistic” approach was discussed to evaluate the energy performance of central air-conditioning system for an extra-large commercial building in a subtropical city. All procedures were described in detail, including field investigation method, field measurement instruments, data processing and data analyzing. The main factors affecting energy consumption of air-conditioning system were analyzed and the annual cooling-energy use intensity of this building was calculated and also compared with other shopping malls and other types of buildings in Guangzhou. And COP (coefficient of performance) of chiller, water transfer factor of chilled water system and cooling water system were taken into consideration. At last, the thermal comfort and indoor air quality issues were addressed. The results show that the chilled water pumps are over-sized and the indoor environmental quality should be improved. The purpose of this work is to provide reference for energy performance assessment method for air-conditioning system.

  7. Benefits of Leapfrogging to Superefficiency and Low Global Warming Potential Refrigerants in Room Air Conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Nihar K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wei, Max [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Letschert, Virginie [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Phadke, Amol A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-10-01

    Hydrofluorocarbons (HFCs) emitted from uses such as refrigerants and thermal insulating foam, are now the fastest growing greenhouse gases (GHGs), with global warming potentials (GWP) thousands of times higher than carbon dioxide (CO2). Because of the short lifetime of these molecules in the atmosphere,1 mitigating the amount of these short-lived climate pollutants (SLCPs) provides a faster path to climate change mitigation than control of CO2 alone. This has led to proposals from Africa, Europe, India, Island States, and North America to amend the Montreal Protocol on Substances that Deplete the Ozone Layer (Montreal Protocol) to phase-down high-GWP HFCs. Simultaneously, energy efficiency market transformation programs such as standards, labeling and incentive programs are endeavoring to improve the energy efficiency for refrigeration and air conditioning equipment to provide life cycle cost, energy, GHG, and peak load savings. In this paper we provide an estimate of the magnitude of such GHG and peak electric load savings potential, for room air conditioning, if the refrigerant transition and energy efficiency improvement policies are implemented either separately or in parallel.

  8. The conference of Russian Association of Engineers for Heating, Ventilation, Air-Conditioning, Heat Supply and Building Thermal Physics (ABOK

    Directory of Open Access Journals (Sweden)

    V.M. Yakubson

    2014-04-01

    Full Text Available On April, 11th, in Lenexpo the XVI conference of Russian Association of Engineers for Heating, Ventilation, Air-Conditioning, Heat Supply and Building Thermal Physics (ABOK “Effective HVAC and Heat Supply Systems” took place. There were a lot of presentations of new equipment for building systems and networks. All these reports were dedicated to the ways to make buildings more comfortable for people, to increase the energy efficiency, to reduce expenses and to improve the production efficiency. But besides the specific equipment, there were some reports dedicated to more general problems in design, installation and maintenance of building systems and networks

  9. 77 FR 16769 - Energy Conservation Program for Certain Industrial Equipment: Energy Conservation Standards and...

    Science.gov (United States)

    2012-03-22

    ... Period The DOE test procedure for commercial air-conditioning equipment does not provide for a compressor... commercial air-conditioning equipment, manufacturers may direct AHRI to run the tested unit's compressor for... Conservation Standards and Test Procedures for Commercial Heating, Air-Conditioning, and...

  10. Human requirements in future air-conditioned environments

    DEFF Research Database (Denmark)

    Fanger, Povl Ole

    1999-01-01

    : better indoor air quality increases productivity and decreases SBS symptoms; unnecessary indoor pollution sources should be avoided; the air should be served cool and dry to the occupants; small amounts of clean air should be served gently, close to the breathing zone of each individual; individual......Although air-conditioning has played a positive role for economic development in warm climates, its image is globally mixed. Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from Sick Building Syndrome (SBS) symptoms......, even though existing standards and guidelines are met. A paradigm shift from rather mediocre to excellent indoor environments is foreseen in the 21st century. Based on existing information and on new research results, five principles are suggested as elements behind a new philosophy of excellence...

  11. Human requirements in future air-conditioned environments

    DEFF Research Database (Denmark)

    Fanger, Povl Ole

    in the built environment: better indoor air quality increases productivity and decreases SBS symptoms; unnecessary indoor pollution sources should be avoided; the air should be served cool and dry to the occupants; personalized ventilation, i.e. small amounts of clean air, should be provided gently......Air-conditioning of buildings has played a very positive role for economic development in warm climates. Still its image is globally mixed. Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from SBS symptoms, even...... though existing standards and guidelines are met. A paradigm shift from rather mediocre to excellent indoor environments is foreseen in buildings in the 21st century. Based on existing information and on new research results, five principles are suggested as elements behind a new philosophy of excellence...

  12. Energy performance of supermarket refrigeration and air conditioning integrated systems

    International Nuclear Information System (INIS)

    The electricity consumption for air conditioning and refrigerated cases in large supermarkets represents a substantial share of the total electricity consumption. The energy efficiency of supermarkets can be improved by optimising components design, recovering thermal and refrigerating energy, adopting innovative technology solutions, integrating the HVAC system with medium temperature and low-temperature refrigeration plants and, finally, reducing thermal loads on refrigerated cases. This study is aimed at investigating the performance of different lay-out and technological solutions and at finding the potential for improving energy efficiency over the traditional systems in different climates. In the analysis chillers and heat pumps working with R410A, medium temperature systems working with R404A and low-temperature systems working both with R404A and R744 were considered. The investigated solutions enable an annual energy saving higher than 15% with respect to the baseline solution for the considered climates.

  13. Experimental Research on Liquid Desiccant Air-conditioning Unit

    Directory of Open Access Journals (Sweden)

    Feng Yueyan

    2016-01-01

    Full Text Available An experimental device of liquid desiccant air conditioning system is established. Experimental tests about the temperature difference between diluted solution of inlet and concentrated solution of exit in the solution heat exchanger are carried on, and CaCl2 solution is used as desiccant. Results show that: the fluctuation range in the day at different times of the basic difference of the measured temperature does not exceed 1°C, and the temperature difference between diluted solution of inlet and concentrated solution of exit in solution heat exchanger appears the minimum value of 2.7°C and the maximum value of 10.2°C. Also, the percent of the additional load and the ratio of additional load to the evaporator load are analyzed.

  14. 8th International Symposium on Heating, Ventilation and Air Conditioning

    CERN Document Server

    Zhu, Yingxin; Li, Yuguo; Vol.1 Indoor and Outdoor Environment; Vol.2 HVAC&R Component and Energy System; Vol.3 Building Simulation and Information Management

    2014-01-01

    Proceedings of the 8th International Symposium on Heating, Ventilation and Air Conditioning is based on the 8th International Symposium of the same name (ISHVAC2013), which took place in Xi’an on October 19-21, 2013. The conference series was initiated at Tsinghua University in 1991 and has since become the premier international HVAC conference initiated in China, playing a significant part in the development of HVAC and indoor environmental research and industry around the world. This international conference provided an exclusive opportunity for policy-makers, designers, researchers, engineers and managers to share their experience. Considering the recent attention on building energy consumption and indoor environments, ISHVAC2013 provided a global platform for discussing recent research on and developments in different aspects of HVAC systems and components, with a focus on building energy consumption, energy efficiency and indoor environments. These categories span a broad range of topics, and the proce...

  15. Reduced bleed air extraction for DC-10 cabin air conditioning

    Science.gov (United States)

    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.

  16. Preventive maintenance plan of the air-conditioning duct using the ACM-sensor

    International Nuclear Information System (INIS)

    Air-conditioning duct is difficult to predict the date to occur of corrosion such as affect the function. Therefore, the current conservation method is mostly corrective maintenance. Therefore, we used the test pieces of six types and ACM-sensor in order to solve the corrosion speed from corrosion environment and relationship of corrosion quantity of test pieces. In addition, was used the duct molded articles various in order to check the corrosion degree of when processed the duct. As a result, we were selected crust body constituting a duct and optimal combination of the flange by solve the corrosion speed of the test pieces various. Thus, it performs preventive disposal before to occur of corrosion such as affect the function by predicting the duct life from corrosion speed, and lead to stability and safe operating by appropriate maintenance of equipment. (author)

  17. Air Conditioning Compressor Air Leak Detection by Image Processing Techniques for Industrial Applications

    OpenAIRE

    Pookongchai Kritsada; Nakornrat Prasit; Sookananta Bongkoj; Buasri Panhathai

    2015-01-01

    This paper presents method to detect air leakage of an air conditioning compressor using image processing techniques. Quality of air conditioning compressor should not have air leakage. To test an air conditioning compressor leak, air is pumped into a compressor and then submerged into the water tank. If air bubble occurs at surface of the air conditioning compressor, that leakage compressor must be returned for maintenance. In this work a new method to detect leakage and search leakage point...

  18. Lorentz transformations: Einstein's derivation simplified

    CERN Document Server

    Rothenstein, B; Popescu, Stefan; Rothenstein, Bernhard

    2007-01-01

    We show that the Lorentz transformations for the space-time coordinates of the same event are a direct consequence of the principle of relativity and of Einstein's distant clocks synchronization procedure. In our approach, imposing the linear character of the Lorentz transformations we guess that the transformation equation for the space coordinate has the form x=ax'+cbt'. Imposing the condition that it accounts for the time dilation relativistic effect and taking into account the fact that due to the clock synchronization a la Einstein the space-time coordinates of the same event in the two frames are related by x=ct and x'=ct', we find out expressions for a and b. Dividing the transformation equation for the space coordinate by c we obtain the transformation equation for the time coordinate t=at'+b/cx'. Combining the two transformation equations we obtain directly the inverse Lorentz transformations.

  19. Prediction of Air Conditioning Load Response for Providing Spinning Reserve - ORNL Report

    Energy Technology Data Exchange (ETDEWEB)

    Kueck, John D [ORNL; Kirby, Brendan J [ORNL; Ally, Moonis Raza [ORNL; Rice, C Keith [ORNL

    2009-02-01

    This report assesses the use of air conditioning load for providing spinning reserve and discusses the barriers and opportunities. Air conditioning load is well suited for this service because it often increases during heavy load periods and can be curtailed for short periods with little impact to the customer. The report also provides an appendix describing the ambient temperature effect on air conditioning load.

  20. 40 CFR 86.161-00 - Air conditioning environmental test facility ambient requirements.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Air conditioning environmental test... conditioning environmental test facility ambient requirements. The goal of an air conditioning test facility is..., within the test cell, during all phases of the air conditioning test sequence to 95 ±2 °F on average...

  1. 40 CFR 86.162-03 - Approval of alternative air conditioning test simulations.

    Science.gov (United States)

    2010-07-01

    ... alternative air conditioning test simulations. (a) Upon petition from a manufacturer or upon the Agency's own initiative, the Administrator will approve a simulation of the environmental cell for air conditioning test... the tailpipe emissions, air conditioning compressor load, and fuel economy. (2) For any...

  2. 40 CFR 86.166-12 - Method for calculating emissions due to air conditioning leakage.

    Science.gov (United States)

    2010-07-01

    ... to air conditioning leakage. 86.166-12 Section 86.166-12 Protection of Environment ENVIRONMENTAL... for calculating emissions due to air conditioning leakage. This section describes procedures used to determine a refrigerant leakage rate in grams per year from vehicle-based air conditioning units....

  3. 40 CFR 86.165-12 - Air conditioning idle test procedure.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Air conditioning idle test procedure... Complete Heavy-Duty Vehicles; Test Procedures § 86.165-12 Air conditioning idle test procedure. (a) Applicability. This section describes procedures for determining air conditioning-related CO2 emissions...

  4. 76 FR 17487 - Protection of Stratospheric Ozone: New Substitute in the Motor Vehicle Air Conditioning Sector...

    Science.gov (United States)

    2011-03-29

    ...: New Substitute in the Motor Vehicle Air Conditioning Sector Under the Significant New Alternatives... Stratospheric Ozone: New Substitute in the Motor Vehicle Air Conditioning Sector Under the Significant New... expanding the list of acceptable substitutes for use in the motor vehicle air conditioning end-use as...

  5. Air Conditioner Charging. Automotive Mechanics. Air Conditioning. Instructor's Guide [and] Student Guide.

    Science.gov (United States)

    Spignesi, B.

    This instructional package, one in a series of individualized instructional units on automobile air conditioning, consists of a student guide and an instructor guide dealing with air conditioning charging. Covered in the module are checking the air conditioning system for leaks, checking and adding refrigerant oil as needed, evacuating the system,…

  6. Multiple Fiztgerald-Lorentz contractions

    CERN Document Server

    Geurdes, J F

    2001-01-01

    In a recent paper, Harada and Sachs suggested that the Fitzgerald-Lorentz contraction does not refer to a physical contraction but can perhaps best be seen as a 'currency conversion'. In the present paper, this view is inspected, and it is found, beyond the immediate frame of the interpretation, that the Fitzgerald-Lorentz contraction leads to a contradiction in a system of more than two observers. A possible physical system in which this can occur is a relativistic (ideal) gas or fluid.

  7. Relationship between the merit factor of thermoelectric materials and the air conditioning unit of urban electric cars

    International Nuclear Information System (INIS)

    The main benefit of electric cars is to reduce air pollution in cities that is thus desirable to equip them with non polluting air conditioning units and this rules out frigorific compressors operating with CFC. The planned replacement of CFC by HFC is at best an interim solution. The best solution is certainly to use thermoelectric air conditioning units, which are inherently pollution-free. However, these have a fairly low COPF when compared to traditional compressor units. We study the relationship between the cooling of the interior of urban electric cars and the merit factor of the thermoelectric material in their Peltier unit. This should help provide concrete target properties of future T E materials. copyright 1995 American Institute of Physics

  8. Evaluation of rotor-bearing system dynamic response to unbalance. [air conditioning equipment

    Science.gov (United States)

    Thaller, R. E.; Ozimek, D. W.

    1979-01-01

    The vibration environment within air conditioner rotating machinery referred to as an air cycle machine (ACM) was investigated to effectively increase ACM reliability. To assist in the selection of design changes which would result in improved ACM performance, various design modifications were incorporated into a baseline ACM configuration. For each design change, testing was conducted with the best balance achieveable (baseline) and with various degrees of unbalance. Relationships between unbalance (within the context of design changes) and the parameters associated with design goals were established. The results of rotor dynamics tests used to establish these relationships are presented.

  9. Fractional Fourier transform of Lorentz beams

    Institute of Scientific and Technical Information of China (English)

    Zhou Guo-Quan

    2009-01-01

    This paper introduces Lorentz beams to describe certain laser sources that produce highly divergent fields. The fractional Fourier transform (FRFT) is applied to treat the propagation of Lorentz beams. Based on the definition of convolution and the convolution theorem of the Fourier transform, an analytical expression for a Lorentz beam passing through a FRFT system has been derived. By using the derived formula, the properties of a Lorentz beam in the FRFT plane are illustrated numerically.

  10. Lorentz transformations of open systems

    OpenAIRE

    Peres, Asher; Terno, Daniel R.

    2001-01-01

    We consider open dynamical systems, subject to external interventions by agents that are not completely described by the theory (classical or quantal). These interventions are localized in regions that are relatively spacelike. Under these circumstances, no relativistic transformation law exists that relates the descriptions of the physical system by observers in relative motion. Still, physical laws are the same in all Lorentz frames.

  11. Lorentz invariance and gauge equivariance

    International Nuclear Information System (INIS)

    Trying to place Lorentz and gauge transformations on the same foundation, it turns out that the first one generates invariance, the second one equivariance, at least for the abelian case. This similarity is not a hypothesis but is supported by and a consequence of the path integral formalism in quantum field theory.

  12. Lorentz contraction and accelerated systems

    OpenAIRE

    Tartaglia, Angelo; Ruggiero, Matteo Luca

    2003-01-01

    The paper discusses the problem of the Lorentz contraction in accelerated systems, in the context of the special theory of relativity. Equal proper accelerations along different world lines are considered, showing the differences arising when the world lines correspond to physically connected or disconnected objects. In all cases the special theory of relativity proves to be completely self-consistent

  13. One way to Lorentz's Transformations

    CERN Document Server

    Bessonov, E G

    2012-01-01

    The derivation of Lorentz Transformations (LT) based on the Principle of Relativity and dependence of the rate of clocks tick (time dilation) on their velocity is presented. The analysis of different ways of the LT derivation allows to look at LT and their consequences from different standpoints, to make them more accessible to a wide circle of readers interested in the relativistic physics.

  14. Cross Sections and Lorentz Violation

    OpenAIRE

    Colladay, Don; Kostelecky, Alan

    2001-01-01

    The derivation of cross sections and decay rates in the Lorentz-violating standard-model extension is discussed. General features of the physics are described, and some conceptual and calculational issues are addressed. As an illustrative example, the cross section for the specific process of electron-positron pair annihilation into two photons is obtained.

  15. Lorentz contraction and accelerated systems

    International Nuclear Information System (INIS)

    The paper discusses the problem of the Lorentz contraction in accelerated systems, in the context of the special theory of relativity. Equal proper accelerations along different world lines are considered, showing the differences arising when the world lines correspond to physically connected or disconnected objects. In all cases the special theory of relativity proves to be completely self-consistent

  16. Testing local Lorentz invariance with gravitational waves

    Science.gov (United States)

    Kostelecký, V. Alan; Mewes, Matthew

    2016-06-01

    The effects of local Lorentz violation on dispersion and birefringence of gravitational waves are investigated. The covariant dispersion relation for gravitational waves involving gauge-invariant Lorentz-violating operators of arbitrary mass dimension is constructed. The chirp signal from the gravitational-wave event GW150914 is used to place numerous first constraints on gravitational Lorentz violation.

  17. Testing local Lorentz invariance with gravitational waves

    OpenAIRE

    Kostelecky, Alan; Mewes, Matthew

    2016-01-01

    The effects of local Lorentz violation on dispersion and birefringence of gravitational waves are investigated. The covariant dispersion relation for gravitational waves involving gauge-invariant Lorentz-violating operators of arbitrary mass dimension is constructed. The chirp signal from the gravitational-wave event GW150914 is used to place numerous first constraints on gravitational Lorentz violation.

  18. Modelling and simulation of air-conditioning cycles

    Science.gov (United States)

    Rais, Sandi; Kadono, Yoshinori; Murayama, Katsunori; Minakuchi, Kazuya; Takeuchi, Hisae; Hasegawa, Tatsuya

    2016-05-01

    The heat-pump cycle for air conditioning was investigated both numerically and experimentally by evaluating the coefficient of performance (COP) under Japanese Industrial Standard (JIS B 8619:1999) and ANSI/AHRI standard 750-2007 operating conditions. We used two expansion valve coefficients Cv_{(\\varphi )} = 0.12 for standard operating conditions (Case 1) approaching 1.3 MPa at high pressure and 0.2 MPa at low pressure, and Cv_{(\\varphi )} = 0.06 namely poor operating conditions (Case 2). To improve the performance of the air conditioner, we compared the performance for two outside air temperatures, 35 and 40 °C (Case 3). The simulation and experiment comparison resulted the decreasing of the COP for standard operating condition is equal to 14 %, from 3.47 to 2.95 and a decrease of the cooling capacity is equal to 18 %, from 309.72 to 253.53 W. This result was also occurred in poor operating condition which the COP was superior at 35 °C temperature.

  19. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System

    Science.gov (United States)

    Zhao, Baiwang; Peng, Na; Liang, Canzeng; Yong, Wai Fen; Chung, Tai-Shung

    2015-01-01

    In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18–22 g/m3 to a range of 13.5–18.3 g/m3. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process. PMID:26580660

  20. Central air conditioning based on adsorption and solar energy

    International Nuclear Information System (INIS)

    This paper presents the characterization and the pre-dimensioning of an adsorption chiller as part of a 20 kW air conditioning central unit for cooling a set of rooms that comprises an area of 110 m2. The system is basically made up of a cold water storage tank supplied by an activated carbon-methanol adsorption chiller, a hot water storage tank, fed by solar energy and natural gas, and a fan-coil. During an acclimatization of 8 h (9-17 h), the following parameters were obtained for dimensioning the cooling system: 504 kg of activated carbon, 180 L of methanol, 7000 L of hot water, 10,300 L of cold water with its temperature varying in the fan-coil from 1 deg. C to 14 C. Considering the mean value of the total daily irradiation in Joao Pessoa (7o8'S, 34o50'WG), and a cover of regenerating heat supplied by solar energy equivalent to 70%, the adsorption chiller's expected coefficient of performance (COP) was found to be around 0.6.

  1. Thermoeconomic evaluation of air conditioning system with chilled water storage

    International Nuclear Information System (INIS)

    Highlights: • A new thermoeconomic evaluation methodology has been presented. • The relationship between thermodynamic and economic performances has been revealed. • A key point for thermal storage technology further application is discovered. • A system has been analyzed via the new method and EUD method. - Abstract: As a good load shifting technology for power grid, chilled energy storage has been paid more and more attention, but it always consumes more energy than traditional air conditioning system, and the performance analysis is mostly from the viewpoint of peak-valley power price to get cost saving. The paper presents a thermoeconomic evaluation methodology for the system with chilled energy storage, by which thermodynamic performance influence on cost saving has been revealed. And a system with chilled storage has been analyzed, which can save more than 15% of power cost with no energy consumption increment, and just certain difference between peak and valley power prices can make the technology for good economic application. The results show that difference between peak and valley power prices is not the only factor on economic performance, thermodynamic performance of the storage system is the more important factor, and too big price difference is a barrier for its application, instead of for more cost saving. All of these give a new direction for thermal storage technology application

  2. Control Techniques in Heating, Ventilating and Air Conditioning Systems

    Directory of Open Access Journals (Sweden)

    H. Mirinejad

    2008-01-01

    Full Text Available Problem statement: Heating, Ventilating and Air Conditioning (HVAC systems are among the main installations in residential, commercial and industrial buildings. The purpose of the HVAC systems is normally to provide a comfortable environment in terms of temperature, humidity and other environmental parameters for the occupants as well as to save energy. Achieving these objectives requires a suitable control system design. Approach: In this overview, thermal comfort level and ISO comfort field is introduced, followed by a review and comparison of the main existing control techniques used in HVAC systems to date. Results: The present overview shows that intelligent controllers which are based on the human sensation of thermal comfort have a better performance in providing thermal comfort as well as energy saving than the traditional controllers and those based on a model of the HVAC system. Conclusion: Such an overview provides an insight into current control methods in HVAC systems and can help scholars and HVAC learners to have the comprehensive information about a variety of control techniques in the field of HVAC and therefore to better design a proper controller for their work

  3. Assessing summertime urban air conditioning consumption in a semiarid environment

    Science.gov (United States)

    Salamanca, F.; Georgescu, M.; Mahalov, A.; Moustaoui, M.; Wang, M.; Svoma, B. M.

    2013-09-01

    Evaluation of built environment energy demand is necessary in light of global projections of urban expansion. Of particular concern are rapidly expanding urban areas in environments where consumption requirements for cooling are excessive. Here, we simulate urban air conditioning (AC) electric consumption for several extreme heat events during summertime over a semiarid metropolitan area with the Weather Research and Forecasting (WRF) model coupled to a multilayer building energy scheme. Observed total load values obtained from an electric utility company were split into two parts, one linked to meteorology (i.e., AC consumption) which was compared to WRF simulations, and another to human behavior. WRF-simulated non-dimensional AC consumption profiles compared favorably to diurnal observations in terms of both amplitude and timing. The hourly ratio of AC to total electricity consumption accounted for ˜53% of diurnally averaged total electric demand, ranging from ˜35% during early morning to ˜65% during evening hours. Our work highlights the importance of modeling AC electricity consumption and its role for the sustainable planning of future urban energy needs. Finally, the methodology presented in this article establishes a new energy consumption-modeling framework that can be applied to any urban environment where the use of AC systems is prevalent.

  4. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System.

    Science.gov (United States)

    Zhao, Baiwang; Peng, Na; Liang, Canzeng; Yong, Wai Fen; Chung, Tai-Shung

    2015-01-01

    In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18-22 g/m³ to a range of 13.5-18.3 g/m³. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process. PMID:26580660

  5. Hollow Fiber Membrane Dehumidification Device for Air Conditioning System

    Directory of Open Access Journals (Sweden)

    Baiwang Zhao

    2015-11-01

    Full Text Available In order to provide a comfortable living and working environment indoors in tropical countries, the outdoor air often needs to be cooled and dehumidified before it enters the rooms. Membrane separation is an emerging technology for air dehumidification and it is based on the solution diffusion mechanism. Water molecules are preferentially permeating through the membranes due to its smaller kinetic diameter and higher condensability than the other gases. Compared to other dehumidification technologies such as direct cooling or desiccation, there is no phase transition involved in membrane dehumidification, neither the contact between the fresh air stream and the desiccants. Hence, membrane dehumidification would not only require less energy consumption but also avoid cross-contamination problems. A pilot scale air dehumidification system is built in this study which comprises nine pieces of one-inch PAN/PDMS hollow fiber membrane modules. A 150 h long-term test shows that the membrane modules has good water vapor transport properties by using a low vacuum force of only 0.78 bar absolute pressure at the lumen side. The water vapor concentration of the feed humid air decreases dramatically from a range of 18–22 g/m3 to a range of 13.5–18.3 g/m3. Most importantly, the total energy saving is up to 26.2% compared with the conventional air conditioning process.

  6. Assessing summertime urban air conditioning consumption in a semiarid environment

    International Nuclear Information System (INIS)

    Evaluation of built environment energy demand is necessary in light of global projections of urban expansion. Of particular concern are rapidly expanding urban areas in environments where consumption requirements for cooling are excessive. Here, we simulate urban air conditioning (AC) electric consumption for several extreme heat events during summertime over a semiarid metropolitan area with the Weather Research and Forecasting (WRF) model coupled to a multilayer building energy scheme. Observed total load values obtained from an electric utility company were split into two parts, one linked to meteorology (i.e., AC consumption) which was compared to WRF simulations, and another to human behavior. WRF-simulated non-dimensional AC consumption profiles compared favorably to diurnal observations in terms of both amplitude and timing. The hourly ratio of AC to total electricity consumption accounted for ∼53% of diurnally averaged total electric demand, ranging from ∼35% during early morning to ∼65% during evening hours. Our work highlights the importance of modeling AC electricity consumption and its role for the sustainable planning of future urban energy needs. Finally, the methodology presented in this article establishes a new energy consumption-modeling framework that can be applied to any urban environment where the use of AC systems is prevalent. (letter)

  7. Shakedown Test and Function of Removable Onboard Air-conditioning System%车载移动式空调机的性能与调试

    Institute of Scientific and Technical Information of China (English)

    孙琦; 嵇翠川

    2011-01-01

    This article introduces the main functions and applications of removable onboard air-conditioning system, introduces the design of vehicles equipped with removable onboard air-conditioning, introduces the integrated debug methods and results.%介绍了研制车载移动式空调机的用途、主要技术性能,叙述了移动式空调机装载厢车的设计、设备联合调试的方法和调试结果。

  8. Energy Savings Potential and Research, Development, & Demonstration Opportunities for Commercial Building Heating, Ventilation, and Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2011-09-01

    This report covers an assessment of 182 different heating, ventilation, and air-conditioning (HVAC) technologies for U.S. commercial buildings to identify and provide analysis on 17 priority technology options in various stages of development. The analyses include an estimation of technical energy-savings potential, description of technical maturity, description of non-energy benefits, description of current barriers for market adoption, and description of the technology’s applicability to different building or HVAC equipment types. From these technology descriptions, are suggestions for potential research, development and demonstration (RD&D) initiatives that would support further development of the priority technology options.

  9. Energy Savings Potential and Research, Development, & Demonstration Opportunities for Residential Building Heating, Ventilation, and Air Conditioning Systems

    Energy Technology Data Exchange (ETDEWEB)

    Goetzler, William [Navigant Consulting, Inc., Burlington, MA (United States); Zogg, Robert [Navigant Consulting, Inc., Burlington, MA (United States); Young, Jim [Navigant Consulting, Inc., Burlington, MA (United States); Schmidt, Justin [Navigant Consulting, Inc., Burlington, MA (United States)

    2012-10-01

    This report is an assessment of 135 different heating, ventilation, and air-conditioning (HVAC) technologies for U.S. residential buildings to identify and provide analysis on 19 priority technology options in various stages of development. The analyses include an estimation of technical energy-savings potential, descriptions of technical maturity, descriptions of non-energy benefits, descriptions of current barriers for market adoption, and descriptions of the technology's applicability to different building or HVAC equipment types. From these technology descriptions, are suggestions for potential research, development and demonstration (RD&D) initiatives that would support further development of the priority technology options.

  10. Lorentz Force Electrical Impedance Tomography

    CERN Document Server

    Grasland-Mongrain, Pol; Chapelon, Jean-Yves; Lafon, Cyril

    2014-01-01

    This article describes a method called Lorentz Force Electrical Impedance Tomography. The electrical conductivity of biological tissues can be measured through their sonication in a magnetic field: the vibration of the tissues inside the field induces an electrical current by Lorentz force. This current, detected by electrodes placed around the sample, is proportional to the ultrasonic pressure, to the strength of the magnetic field and to the electrical conductivity gradient along the acoustic axis. By focusing at different places inside the sample, a map of the electrical conductivity gradient can be established. In this study experiments were conducted on a gelatin phantom and on a beef sample, successively placed in a 300 mT magnetic field and sonicated with an ultrasonic transducer focused at 21 cm emitting 500 kHz bursts. Although all interfaces are not visible, in this exploratory study a good correlation is observed between the electrical conductivity image and the ultrasonic image. This method offers...

  11. Lorentz violation of quantum gravity

    International Nuclear Information System (INIS)

    A quantum gravity theory which becomes renormalizable at short distances due to a spontaneous symmetry breaking of Lorentz invariance and diffeomorphism invariance is studied. A breaking of Lorentz invariance with the breaking patterns SO(3, 1) → O(3) and SO(3, 1) → O(2), describing 3 + 1 and 2 + 1 quantum gravity, respectively, is proposed. A complex time-dependent Schroedinger equation (generalized Wheeler-DeWitt equation) for the wavefunction of the universe exists in the spontaneously broken symmetry phase at Planck energy and in the early universe, uniting quantum mechanics and general relativity. An explanation of the second law of thermodynamics and the spontaneous creation of matter in the early universe can be obtained in the symmetry broken phase of gravity.

  12. Testing Lorentz Symmetry with Gravity

    OpenAIRE

    Bailey, Quentin G.

    2007-01-01

    In this talk, results from the gravitational sector of the Standard-Model Extension (SME) are discussed. The weak-field phenomenology of the resulting modified gravitational field equations is explored. The application of the results to a variety of modern gravity experiments, including lunar laser ranging, Gravity Probe B, binary pulsars, and Earth-laboratory tests, shows promising sensitivity to gravitational coefficients for Lorentz violation in the SME.

  13. Cooling Performance Characteristics on Mobile Air-Conditioning System for Hybrid Electric Vehicles

    OpenAIRE

    Ho-Seong Lee; Moo-Yeon Lee

    2013-01-01

    This study investigates the cooling performance characteristics of the mobile air-conditioning system using R744 (CO2) for the hybrid electric vehicle as an alternative to both the R-134a and the conventional air-conditioning system. The developed air-conditioning system is operated with an electric driven compressor in the battery driving mode and a belt driven compressor in the engine driving mode. The cooling performance characteristics of the developed system have been analyzed by experim...

  14. MAGNETOHYDRODYNAMICS: A METHOD FOR PERFORMANCE ENHANCEMENT IN AIR CONDITIONING AND REFRIGERATION

    OpenAIRE

    N.S.Mane; , H.M.Dange; P. P. Awate

    2015-01-01

    The refrigeration and air conditioning system having low energy consumption and environment friendliness is the main focus of the research department Refrigeration and Air conditioning industry and technical institutes. Efficiency of the refrigeration or air conditioning system working on vapour compression refrigeration cycle can be increased by using the Magneto hydrodynamic principles. Many researchers indicated that the behavior of the refrigerant flowing through vapour compre...

  15. Performance advancement of solar air-conditioning through integrated system design for building

    International Nuclear Information System (INIS)

    This study is to advance the energy performance of solar air-conditioning system through appropriate component integration from the absorption refrigeration cycle and proper high-temperature cooling. In the previous studies, the solar absorption air-conditioning using the working pair of water – lithium bromide (H2O–LiBr) is found to have prominent primary energy saving than the conventional compression air-conditioning for buildings in the hot-humid climate. In this study, three integration strategies have been generated for solar cooling, namely integrated absorption air-conditioning; integrated absorption-desiccant air-conditioning; and integrated absorption-desiccant air-conditioning for radiant cooling. To realize these ideas, the working pair of ammonia – water (NH3–H2O) was used in the absorption cycle, rather than H2O–LiBr. As such, the evaporator and the condenser can be separate from the absorption refrigeration cycle for the new configuration of various integrated design alternatives. Through dynamic simulation, the year-round primary energy saving of the proposed integration strategies for solar NH3–H2O absorption air-conditioning systems could be up to 50.6% and 25.5%, as compared to the conventional compression air-conditioning and the basic solar H2O–LiBr absorption air-conditioning respectively. Consequently, carbon reduction of building air-conditioning can be achieved more effectively through the integrated system design in the hot and humid cities. - Highlights: • Three integration strategies, IAAU, IADAU and IADAU-RC, are proposed to advance solar air-conditioning. • NH3–H2O is adopted for absorption refrigeration instead of H2O–LiBr. • Separate evaporator and condenser, desiccant cooling and radiant cooling are designed for IADAU-RC. • IADAU-RC can have 50.6% primary energy saving against the conventional air-conditioning

  16. A study of energy use for ventilation and air-conditioning systems in Hong Kong

    Science.gov (United States)

    Yu, Chung Hoi Philip

    Most of the local modern buildings are high-rise with enclosed structure. Mechanical ventilation and air conditioning (MVAC) systems are installed for thermal comfort. Various types of MVAC systems found in Hong Kong were critically reviewed with comments on their characteristics in energy efficiency as well as application. The major design considerations were also discussed. Besides MVAC, other energy-consuming components in commercial buildings were also identified, such as lighting, lifts and escalators, office equipment, information technology facilities, etc. A practical approach has been adopted throughout this study in order that the end results will have pragmatic value to the heating, ventilating and air-conditioning (HVAC) industry in Hong Kong. Indoor Air Quality (IAQ) has become a major issue in commercial buildings worldwide including Hong Kong. Ventilation rate is no doubt a critical element in the design of HVAC systems, which can be realized more obviously in railway train compartments where the carbon dioxide level will be built up quickly when the compartments are crowded during rush hours. A study was carried out based on a simplified model using a train compartment that is equipped with an MVAC system. Overall Thermal Transfer Value (OTTV) is a single-value parameter for controlling building energy use and is relatively simple to implement legislatively. The local government has taken a first step in reacting to the worldwide concern of energy conservation and environmental protection since 1995. Different methods of OTTV calculation were studied and the computation results were compared. It gives a clear picture of the advantages and limitations for each method to the building designers. However, due to the limitations of using OTTV as the only parameter for building energy control, some new approaches to a total control of building energy use were discussed and they might be considered for future revision of the building energy codes in Hong

  17. Observational Constraints on Local Lorentz Invariance

    CERN Document Server

    Bluhm, Robert

    2013-01-01

    The idea that local Lorentz invariance might be violated due to new physics that goes beyond the Standard Model of particle physics and Einstein's General Relativity has received a great deal of interest in recent years. At the same time, new experiments have been designed and conducted that are able to test Lorentz symmetry at unprecedented levels. Much of this theoretical and experimental progress has been driven by the development of the framework for investigating Lorentz violation known as the Standard Model Extension (SME). The SME is the lagrangian-based effective field theory that by definition contains all Lorentz-violating interaction terms that can be written as observer scalars involving particle fields in the Standard Model and gravitational fields in a generalized theory of gravity. This includes all terms that could arise from a process of spontaneous Lorentz violation as well as terms that explicitly break Lorentz symmetry. In this article, an overview of the SME is presented, including its mo...

  18. Are Maxwell's equations Lorentz-covariant?

    CERN Document Server

    Redzic, D V

    2016-01-01

    The statement that Maxwell's electrodynamics in vacuum is already covariant under Lorentz transformations is commonplace in the literature. We analyse the actual meaning of that statement and demonstrate that Maxwell's equations are perfectly fit to be Lorentz-covariant; they become Lorentz-covariant if we construct to be so, by postulating certain transformation properties of field functions. In Aristotelian terms, the covariance is a plain potentiality, but not necessarily entelechy.

  19. Lorentz violation dispersion relation and its application

    CERN Document Server

    Xiao, Zhi

    2008-01-01

    We derive modified dispersion relation (MDR) in the Lorentz violation extension of quantum electrodynamics (QED) sector in the standard model extension (SME) framework. Based on the extended Dirac equation and corresponding MDR, we observe the resemblance of the Lorentz violation coupling with spin-gravity coupling. We also develop a neutrino oscillation mechanism induced by the presence of nondiagonal terms of Lorentz violation couplings in 2-flavor space in a 2-spinor formalism by explicitly assuming neutrinos to be Marjorana fermions. We also obtain a much stringent bound ($\\backsim10^{-25}$) on one of the Lorentz violation parameters by applying MDR to the ultrahigh energy cosmic ray (UHECR) problem.

  20. 77 FR 33315 - Protection of Stratospheric Ozone: Alternative for the Motor Vehicle Air Conditioning Sector...

    Science.gov (United States)

    2012-06-06

    ... Air Conditioning Sector Under the Significant New Alternatives Policy (SNAP) Program AGENCY...) within the refrigeration and air-conditioning sector. This final rule only concerns the use of CO 2 in... their suppliers with a refrigerant option subject to use conditions for motor vehicle air...

  1. Automotive Air Conditioning and Heating; Automotive Mechanics (Advanced): 9047.04.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    This document presents an outline for a 135-hour course designed to provide the student with all the foundations necessary to become employable in the automotive air conditioning and heating trade. The course of study includes an orientation to the world of work, the elementary physics of air conditioning and heating, and laboratory experiments…

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

    Science.gov (United States)

    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…

  3. Fast simulation of temperature distribution in air conditioned rooms by using proper orthogonal decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Sempey, A.; Inard, C.; Allery, C. [Laboratoire d' etude des phenomenes de transfert appliques au batiment (LEPTAB), Universite de La Rochelle, pole sciences et technologie, avenue Michel Crepeau, 17042 La Rochelle cedex 1 (France); Ghiaus, C. [Centre Thermique de Lyon (CETHIL) UMR 5008, INSA Lyon, 9, rue de la Physique, 69621 Villeurbanne cedex (France)

    2009-02-15

    Real-time control of air conditioning needs dynamic models of temperature distribution and air velocity field in rooms. Complete models, based on computational fluid dynamics (CFD), give this information, but they are too time-consuming for real-time applications. Therefore, a reduced model is needed. In mixed convection, when the air temperature has negligible variations, the velocity field may be considered fixed. In this case, the size of a CFD model may be reduced by solving only the energy balance equation, then putting this equation in the form of state-space and finally by reducing its order by proper orthogonal decomposition (POD). This algorithm was applied to a room equipped with a fan coil. Four fixed airflow fields, corresponding to negligible air temperature variation, were considered, resulting in four airflow patterns: the air jet sticks to the ceiling and reaches the opposite wall, the air jet falls before reaching the opposite wall, the air jet reaches the ceiling without extending along it, and the air jet falls before reaching the ceiling. The reduced model obtained from these airflow patterns was validated by comparing with CFD results for step variation of inlet temperature. As the order of the reduced model is always lower than seven, it may be used for real-time control applications. (author)

  4. New principle of organization of working process of air conditioning systems at railway and sea transport

    Directory of Open Access Journals (Sweden)

    Andrey KRAJNIUK

    2008-01-01

    Full Text Available An indispensable component of ensuring safe control of railway and sea transport in conditions of hot climate is maintenance of comfortable temperature of air in control cabins and living spaces. Now the interest is restored to use the Air Refrigerating Plants (ARP as they have a wide potential of low-temperature cooling without use of ozone-destructive cooling agents prohibited by decision of the Montreal meeting. At the same time, air conditioning installations on the basis of turbo-expanders have low refrigerating factor, they are very expensive in manufacturing and require a high level of maintenance service.Alternative trend of perfection of air refrigeration units is connected with a new principle of organization of working process, based on the use as expander and compressor of aggregates of cascade exchanger of pressure (CPE. Besides of unsurpassed efficiency of exchange processes, CPE is characterized by simplicity of design and high reliability, including, due to low frequency of rotation (2000-3000 min-1 with practically absence of consumption of mechanical energy on the drive of the rotor. The attractive aspect of application of equipment of conditioning with CPE is the opportunity of organization of working process only due to thermal energy including the utilization in the heat-power installation of transport vehicle.

  5. Radon mitigation in schools utilising heating, ventilating and air conditioning systems

    International Nuclear Information System (INIS)

    As part of a continuing radon in schools technology development effort, EPA's School Evaluation Team has performed radon mitigation in schools by the method of ventilation/pressurisation control technology. Ventilation rates were increased, at a minimum, to meet the American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) standard, Ventilation for Acceptable Indoor Air Quality (ASHRAE 62-1989). This paper presents the results and the preliminary evaluations which led to the team's decision to implement this technology. Factors considered include energy penalties, comfort, indoor air quality (IAQ), building shell tightness, and equipment costs. Cost benefit of heat recovery ventilation was also considered. Earlier results of the SEP team's efforts have indicated a severe ventilation problem within the schools of the United States. Two case studies are presented where HVAC technology was implemented for controlling radon concentrations. One involved the installation of a heat recovery ventilator to depressurise a crawl space and provide ventilation to the classrooms which previously had no mechanical ventilation. The other involved the restoration of a variable air volume system in a two-storey building. The HVAC system's controls were restored and modified to provide a constant building pressure differential to control the entry of radon. Pre-mitigation and post-mitigation indoor air pollutant measurements were taken, including radon, carbon dioxide (CO2), particulates, and bio-aerosols. Long-term monitoring of radon, CO2, building pressure differentials, and indoor/outdoor temperature and relative humidity is presented. (author)

  6. Constraining Lorentz violation with cosmology.

    Science.gov (United States)

    Zuntz, J A; Ferreira, P G; Zlosnik, T G

    2008-12-31

    The Einstein-aether theory provides a simple, dynamical mechanism for breaking Lorentz invariance. It does so within a generally covariant context and may emerge from quantum effects in more fundamental theories. The theory leads to a preferred frame and can have distinct experimental signatures. In this Letter, we perform a comprehensive study of the cosmological effects of the Einstein-aether theory and use observational data to constrain it. Allied to previously determined consistency and experimental constraints, we find that an Einstein-aether universe can fit experimental data over a wide range of its parameter space, but requires a specific rescaling of the other cosmological densities. PMID:19113765

  7. Application of Fuzzy Comprehensive Evaluation to Air-conditioning Competitive Power Analysis

    Institute of Scientific and Technical Information of China (English)

    LU Congda; LIU Gaojin; JIANG Shaofei; LV Chaoqun

    2006-01-01

    As the conceptual design of air-conditioning is done using the theory of Quality Function Deployment (QFD), customer requirements should be understood and the product competitive power be analyzed as exactly as possible for new product designing. Lots of information in the process of this research is fuzzy and uncertain, but traditional QFD can not deal with it well. Fuzzy theory can solve the problem. So a fuzzy model for analyzing product competitive power is formulated in this paper to improve traditional QFD, after that it is applied to analyze air-conditioning competitive power. When air-conditioning competitive power is analyzed using this model, firstly the importance weight of the customer requirements of air-conditioning is determined using the Analytic Hierarchy Process (AHP) weighting process, then air-conditioning competitive power is evaluated using fuzzy comprehensive evaluation. It is proved that the model is feasible and has good applicability.

  8. Opportunities to Reduce Air-Conditioning Loads Through Lower Cabin Soak Temperatures

    International Nuclear Information System (INIS)

    Air-conditioning loads can significantly reduce electric vehicle (EV) range and hybrid electric vehicle (HEV) fuel economy. In addition, a new U. S. emissions procedure, called the Supplemental Federal Test Procedure (SFTP), has provided the motivation for reducing the size of vehicle air-conditioning systems in the United States. The SFTP will measure tailpipe emissions with the air-conditioning system operating. If the size of the air-conditioning system is reduced, the cabin soak temperature must also be reduced, with no penalty in terms of passenger thermal comfort. This paper presents the impact of air-conditioning on EV range and HEV fuel economy, and compares the effectiveness of advanced glazing and cabin ventilation. Experimental and modeled results are presented

  9. Interaction of temperature, humidity, driver preferences, and refrigerant type on air conditioning compressor usage.

    Science.gov (United States)

    Levine, C; Younglove, T; Barth, M

    2000-10-01

    Recent studies have shown large increases in vehicle emissions when the air conditioner (AC) compressor is engaged. Factors that affect the compressor-on percentage can have a significant impact on vehicle emissions and can also lead to prediction errors in current emissions models if not accounted for properly. During 1996 and 1997, the University of California, Riverside, College of Engineering-Center for Environmental Research and Technology (CE-CERT) conducted a vehicle activity study for the California Air Resources Board (CARB) in the Sacramento, CA, region. The vehicles were randomly selected from all registered vehicles in the region. As part of this study, ten vehicles were instrumented to collect AC compressor on/off data on a second-by-second basis in the summer of 1997. Temperature and humidity data were obtained and averaged on an hourly basis. The ten drivers were asked to complete a short survey about AC operational preferences. This paper examines the effects of temperature, humidity, refrigerant type, and driver preferences on air conditioning compressor activity. Overall, AC was in use in 69.1% of the trips monitored. The compressor was on an average of 64% of the time during the trips. The personal preference settings had a significant effect on the AC compressor-on percentage but did not interact with temperature. The refrigerant types, however, exhibited a differential response across temperature, which may necessitate separate modeling of the R12 refrigerant-equipped vehicles from the R134A-equipped vehicles. It should be noted that some older vehicles do get retrofitted with new compressors that use R134A; however, none of the vehicles in this study had been retrofitted. PMID:11288304

  10. Lorentz-Force Hydrophone Characterization

    CERN Document Server

    Grasland-Mongrain, Pol; Gilles, Bruno; Poizat, Adrien; Chapelon, Jean-Yves; Lafon, Cyril

    2014-01-01

    A Lorentz-force hydrophone consists of a thin wire placed inside a magnetic field. When under the influence of an ultrasound pulse, the wire vibrates and an electrical signal is induced by the Lorentz force that is proportional to the pulse amplitude. In this study a compact prototype of such a hydrophone is introduced and characterized, and the hydrodynamic model previously developed is refined. It is shown that the wire tension has a negligible effect on the measurement of pressure. The frequency response of the hydrophone reaches 1 MHz for wires with a diameter ranging between 70 and 400 \\micro m. The hydrophone exhibits a directional response such that the signal amplitude differs by less than 3dB as the angle of the incident ultrasound pulse varies from -20$^o$ and +20$^o$. The linearity of the measured signal is confirmed across the 50 kPa to 10 MPa pressure range, and an excellent resistance to cavitation is observed. This hydrophone is of interest for high pressure ultrasound measurements including Hi...

  11. Lorentz violating kinematics: threshold theorems

    Science.gov (United States)

    Baccetti, Valentina; Tate, Kyle; Visser, Matt

    2012-03-01

    Recent tentative experimental indications, and the subsequent theoretical speculations, regarding possible violations of Lorentz invariance have attracted a vast amount of attention. An important technical issue that considerably complicates detailed calculations in any such scenario, is that once one violates Lorentz invariance the analysis of thresholds in both scattering and decay processes becomes extremely subtle, with many new and naively unexpected effects. In the current article we develop several extremely general threshold theorems that depend only on the existence of some energy momentum relation E(p), eschewing even assumptions of isotropy or monotonicity. We shall argue that there are physically interesting situations where such a level of generality is called for, and that existing (partial) results in the literature make unnecessary technical assumptions. Even in this most general of settings, we show that at threshold all final state particles move with the same 3-velocity, while initial state particles must have 3-velocities parallel/anti-parallel to the final state particles. In contrast the various 3-momenta can behave in a complicatedand counter-intuitive manner.

  12. Neutrinos as Probes of Lorentz Invariance

    International Nuclear Information System (INIS)

    Neutrinos can be used to search for deviations from exact Lorentz invariance. The worldwide experimental program in neutrino physics makes these particles a remarkable tool to search for a variety of signals that could reveal minute relativity violations. This paper reviews the generic experimental signatures of the breakdown of Lorentz symmetry in the neutrino sector

  13. The influences of wall Lorentz force and field Lorentz force on the cylinder drag reduction

    Institute of Scientific and Technical Information of China (English)

    Hui Zhang; Bao-Chun Fan; Zhi-Hna Chen; Yan-Ling Li

    2011-01-01

    In this paper,the effects of Lorentz force on drag reduction for a circular cylinder have been studied experimentally and numerically.Based on its effects on drag reduction,the Lorentz force is found to be classified into two parts:one acts directly on the cylinder,named as the wall Lorentz force,and the other called the field Lorentz force acts on the fluid inside the boundary layer.The wall Lorentz force leads to the generation of a thrust,whereas the field Lorentz force results in drag increase.Since the former dominates the drag variation,the drag would reduce accordingly and even turn into negative (thrust) with the application of Lorentz force.

  14. Hadronic Lorentz Violation in Chiral Perturbation Theory

    CERN Document Server

    Kamand, Rasha; Schindler, Matthias R

    2016-01-01

    Any possible Lorentz violation in the hadron sector must be tied to Lorentz violation at the underlying quark level. The relationships between the theories at these two levels are studied using chiral perturbation theory. Starting from a two-flavor quark theory that includes dimension-four Lorentz-violation operators, the effective Lagrangians are derived for both pions and nucleons, with novel terms appearing in both sectors. Since the Lorentz violation coefficients for nucleons and pions are all related to a single set of underlying quark coefficients, it is possible to place approximate bounds on pion Lorentz violation using only proton and neutron observations. The resulting bounds on four pion parameters are at the $10^{-23}$ level, representing improvements of ten orders of magnitude.

  15. Lorentz violation and perpetual motion

    CERN Document Server

    Eling, C; Jacobson, T; Wall, A C; Eling, Christopher; Foster, Brendan Z.; Jacobson, Ted; Wall, Aron C.

    2007-01-01

    We show that any Lorentz violating theory with two or more propagation speeds is in conflict with the generalized second law of black hole thermodynamics. We do this by identifying a classical energy-extraction method, analogous to the Penrose process, which would decrease the black hole entropy. Although the usual definitions of black hole entropy are ambiguous in this context, we require only very mild assumptions about its dependence on the mass. This extends the result found by Dubovsky and Sibiryakov, which uses the Hawking effect and applies only if the fields with different propagation speeds interact just through gravity. We also point out instabilities that could interfere with their black hole {\\it perpetuum mobile}, but argue that these can be neglected if the black hole mass is sufficiently large.

  16. LORENTZ PHASE IMAGING AND IN-SITU LORENTZ MICROSCOPY OF PATTERNED CO-ARRAYS

    International Nuclear Information System (INIS)

    Understanding magnetic structures and properties of patterned and ordinary magnetic films at nanometer length-scale is the area of immense technological and fundamental scientific importance. The key feature to such success is the ability to achieve visual quantitative information on domain configurations with a maximum ''magnetic'' resolution. Several methods have been developed to meet these demands (Kerr and Faraday effects, differential phase contrast microscopy, magnetic force microscopy, SEMPA etc.). In particular, the modern off-axis electron holography allows retrieval of the electron-wave phase shifts down to 2π/N (with typical N = 10-20, approaching in the limit N ∼ 100) in TEM equipped with field emission gun, which is already successfully employed for studies of magnetic materials at nanometer scale. However, it remains technically demanding, sensitive to noise and needs highly coherent electron sources. As possible alternative we developed a new method of Lorentz phase microscopy [1,2] based on the Fourier solution [3] of magnetic transport-of-intensity (MTIE) equation. This approach has certain advantages, since it is less sensitive to noise and does not need high coherence of the source required by the holography. In addition, it can be realized in any TEM without basic hardware changes. Our approach considers the electron-wave refraction in magnetic materials (magnetic refraction) and became possible due to general progress in understanding of noninterferometric phase retrieval [4-6] dealing with optical refraction. This approach can also be treated as further development of Fresnel microscopy, used so far for imaging of in-situ magnetization process in magnetic materials studied by TEM. Figs. 1-3 show some examples of what kind information can be retrieved from the conventional Fresnel images using the new approach. Most of these results can be compared with electron-holographic data. Using this approach we can shed more light on fine details of

  17. Influence of Cooling to Heating Load Ratio on Optimal Supply Water and Air Temperatures in an Air Conditioning System

    Science.gov (United States)

    Karino, Naoki; Shiba, Takashi; Yokoyama, Ryohei; Ito, Koichi

    In planning an air conditioning system, supply water and air temperatures are important factors from the viewpoint of energy saving and cost reduction. For example, lower temperature supply water and air for space cooling reduce the coefficient of performance of a refrigeration machine, and increase the thickness of heat insulation material. However, they enable larger temperature differences, and reduce equipment sizes and power demand. It is also an important subject to evaluate the effect of the supply water and air temperatures on energy saving and cost reduction on the annual basis by considering not only cooling but also heating loads. The purposes of this paper are to propose an optimal planning method for an air conditioning system with large temperature difference, and to analyze the effect of supply water and air temperatures on the long-term economics through a numerical study for an office building. As a result, it is shown that the proposed method effectively determines supply water and air temperatures, and the influence of the cooling to heating load ratio on the long-term economics is clarified.

  18. Modelling of cooled-ceiling air-conditioning systems: Influences on indoor environment and energy consumption. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Niu, J.

    1994-06-14

    The contents presented in this thesis consist of four principal parts: (1) the critical review of turbulence CFD (Computational Fluid Dynamics) techniques and their application in building air flow study, and the experimental evaluation of the widely used k-epsilon turbulence model for in-room air flow situations; (2) the development of a thermodynamic mathematical model for cooled-ceiling air-conditioning systems, and the enhancement of an existing computer code ACCURACY, and the experimental validation of the convective parameters involved in the models; (3) the combined use of building dynamic simulation and CFD technique for the investigation of thermal comfort and ventilation effectiveness performance of three typical air-conditioning systems, the air-panel type cooled-ceiling (ACC) system, and the water-panel type cooled ceiling (CC) system; and (4) the use of the dynamic model coupled with air-handling-unit (AHU) and primary equipment models to simulate the annual energy consumption of CC systems and all-air systems and to estimate thermal performances of some passive cooling schemes, especially the evaporative free-cooling scheme. The review of the state-of-the-art of turbulence modeling shows that the k-epsilon turbulence model still remains the most-widely used engineering model.

  19. Japanese and American competition in the development of scroll compressors and its impact on the American air conditioning industry

    Energy Technology Data Exchange (ETDEWEB)

    Ushimaru, Kenji (Energy International, Inc., Bellevue, WA (USA))

    1990-02-01

    This report examines the technological development of scroll compressors and its impact on the air conditioning equipment industry. Scroll compressors, although considered to be the compressors of the future for energy-efficient residential heat pumps and possibly for many other applications, are difficult to manufacture on a volume-production base. The manufacturing process requires computer-aided, numerically controlled tools for high-precision fabrication of major parts. Japan implemented a global strategy for dominating the technological world market in the 1970s, and scroll compressor technology benefited from the advent of new-generation machine tools. As a result, if American manufacturers of scroll compressors purchase or are essentially forced to purchase numerically controlled tools from Japan in the future, they will then become dependent on their own competitors because the same Japanese conglomerates that make numerically controlled tools also make scroll compressors. This study illustrates the importance of the basic machine tool industry to the health of the US economy. Without a strong machine tool industry, it is difficult for American manufacturers to put innovations, whether patented or not, into production. As we experience transformation in the air conditioning and refrigeration market, it will be critical to establish a consistent national policy to provide healthy competition among producers, to promote innovation within the industry, to enhance assimilation of new technology, and to eliminate practices that are incompatible with these goals. 72 refs., 8 figs., 1 tab.

  20. Analysis and simulation of mobile air conditioning system coupled with engine cooling system

    International Nuclear Information System (INIS)

    Many components of the mobile air conditioning system and engine cooling system are closely interrelated and make up the vehicle climate control system. In the present paper, a vehicle climate control system model including air conditioning system and engine cooling system has been proposed under different operational conditions. All the components have been modeled on the basis of experimental data. Based on the commercial software, a computer simulation procedure of the vehicle climate control system has been developed. The performance of the vehicle climate control system is simulated, and the calculational data have good agreement with experimental data. Furthermore, the vehicle climate control simulation results have been compared with an individual air conditioning system and engine cooling system. The influences between the mobile air conditioning system and the engine cooling system are discussed

  1. Evaluating Membrane Processes for Air Conditioning; Highlights in Research and Development, NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-06-01

    This NREL Highlight discusses a recent state-of-the-art review of membrane processes for air conditioning that identifies future research opportunities. This highlight is being developed for the June 2015 S&T Alliance Board meeting.

  2. Temperature and humidity independent control (THIC) of air-conditioning system

    CERN Document Server

    Liu, Xiaohua; Zhang, Tao

    2014-01-01

    This book presents the main components of the Temperature and Humidity Independent Control (THIC) of air-conditioning systems, including dehumidification devices, high-temperature cooling devices and indoor terminal devices.

  3. Modeling of an Air Conditioning System with Geothermal Heat Pump for a Residential Building

    OpenAIRE

    Silvia Cocchi; Sonia Castellucci; Andrea Tucci

    2013-01-01

    The need to address climate change caused by greenhouse gas emissions attaches great importance to research aimed at using renewable energy. Geothermal energy is an interesting alternative concerning the production of energy for air conditioning of buildings (heating and cooling), through the use of geothermal heat pumps. In this work a model has been developed in order to simulate an air conditioning system with geothermal heat pump. A ground source heat pump (GSHP) uses the shallow ground a...

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

    OpenAIRE

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

    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 con...

  5. Computerized Simulation of Automotive Air-Conditioning System: Development of Mathematical Model and Its Validation

    OpenAIRE

    Haslinda Mohamed Kamar; Mohd Yusoff Senawi; Nazri Kamsah

    2012-01-01

    A semi-empirical model for simulating thermal and energy performance of an automotive air-conditioning (AAC) system in passenger vehicles has been developed. The model consists of two sections, namely empirical evaporator correlations and dynamic load simulation. The correlations used consider sensible and latent heat transfer performance of the evaporator coil. The correlations were obtained from the experimental data of actual air conditioning system for a compact size passenger car. The se...

  6. Numerical Analysis of Exergy for Air-Conditioning Influenced by Ambient Temperature

    OpenAIRE

    Jing-Nang Lee; Chien-Chih Chen; Chen-Ching Ting

    2014-01-01

    The article presents numerical analysis of exergy for air-conditioning influenced by ambient temperature. The model of numerical simulation uses an integrated air conditioning system exposed in varied ambient temperature to observe change of the four main devices, the compressor, the condenser, the capillary, and the evaporator in correspondence to ambient temperature. The analysis devices of the four devices’s exergy influenced by the varied ambient temperature and found that the...

  7. Application of Computer Model to Estimate the Consistency of Air Conditioning Systems Engineering

    OpenAIRE

    Amal El-Berry; Afrah Al-Bossly

    2013-01-01

    Reliability engineering is utilized to predict the performance and optimization of the design and maintenance of air conditioning systems. There are a number of failures associated with the conditioning systems. The failures of an air conditioner such as turn on, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply and loss of air flow entirely are mainly due to a variety of problems with one or more components of an air conditioner o...

  8. Performance of desiccant air conditioning system with geothermal energy under different climatic conditions

    International Nuclear Information System (INIS)

    Highlights: • The performance of the hybrid air conditioning system is studied. • The influence of important operating parameters are estimated. • The ventilation, makeup and mix cycles are investigated at different climate. • The highest COP of the hybrid air conditioning system is 1.03. • The hybrid system provides a human thermal comfort at different climates. - Abstract: Energy saving still and continue a major seek in our life, due to the continuous increase in energy consumptions. So, a desiccant air conditioning system with geothermal energy is conducted in the current study. The thermal analysis of air conditioning system with its different components desiccant wheel, solar collector, heat exchanger, ground heat exchanger and water spray evaporative cooler is presented. Three different air conditioning cycles are simulated in the current study for different zones like: hot-dry zone, warm-dry zone, hot-humid zone and the warm-humid zone. The results show that the desiccant air conditioning system successfully provides a better thermal comfort condition in different climates. This hybrid system significantly decreases the supplied air temperature from 12.7 to 21.7 °C at different climate zones. When ωin,air and TReg increasing, COP decreases and the ventilation cycle provides the better COP. The highest COP value of the desiccant air conditioning system is about 1.03 while the lowest value is about 0.15. The SHR of makeup cycle is higher than that ventilation cycle at warm and hot-humid zone and vice versa at warm and hot-dry zone. The highest SHR value of the desiccant air conditioning system is about 0.99 while the lowest value is about 0.2. The Tsup,air, ωsup,air, COP and SHR isolines may easily be used for pre-evaluating of various cooling cycles in different climates. The hybrid system provides a human thermal comfort at different climates

  9. New Energy-Efficient Electromagnetic Clutch for Automotive Air Conditioning Compressors

    OpenAIRE

    Baumgart, Rico; van der Seylberg, Frank; Aurich, Joerg; von Unwerth, Thomas

    2012-01-01

    Even if the air conditioning is switched off, the internal combustion engine in today’s cars continues to drive the common compressor. To avoid resulting power losses, the automotive industry aspires to apply electromagnetic clutches. When the air conditioning is used, however, CO2-emission increases significantly because the electromag-netic coil consumes electricity. The CO2-reduction per year is consequently very low, which is why new compressor clutches were developed that do not require ...

  10. Solar technology assessment project. Volume 4: Solar air conditioning: Active, hybrid and passive

    Science.gov (United States)

    Yellott, J. I.

    1981-04-01

    The status of absorption cycle solar air conditioning and the Rankine cycle solar cooling system is reviewed. Vapor jet ejector chillers, solar pond based cooling, and photovoltaic compression air conditioning are also briefly discussed. Hybrid solar cooling by direct and indirect evaporative cooling, and dehumidification by desiccation are described and discussed. Passive solar cooling by convective and radiative processes, evaporative cooling by passive processes, and cooling with roof ponds and movable insulation are reviewed. Federal and state involvement in solar cooling is discussed.

  11. Simulation of Solar Air-Conditioning System with Salinity Gradient Solar Pond

    OpenAIRE

    Safwan Kanan, Jonathan Dewsbury, Gregory Lane-Serff

    2015-01-01

    In hot dry climates, due to the high demand for space air conditioning during summer and the abundance of solar radiation, solar air conditioning is a promising approach to reduce the energy consumption and negative environmental impact of buildings. Solar cooling systems have used various types of collectors to drive chillers. In this paper, a salinity gradient solar pond is suggested as a collector to drive an absorption chiller, to provide cool air for a house during hot and dry weather. A...

  12. Exergy and Thermoeconomic Analysis for an Underground Train Station Air-Conditioning Cooling System

    OpenAIRE

    Ke Yang Liao; Yew Khoy Chuah

    2016-01-01

    The necessity of air-conditioning causes the enormous energy use of underground train stations. Exergy and thermoeconomic analysis is applied to the annual operation of the air-conditioning system of a large underground train station in Taiwan. The current installation and the monitored data are taken to be the base case, which is then compared to three different optimized designs. The total revenue requirement levelized cost rate and the total exergy destruction rate are used to evaluate the...

  13. Ice Storage Air-Conditioning System Simulation with Dynamic Electricity Pricing: A Demand Response Study

    Directory of Open Access Journals (Sweden)

    Chi-Chun Lo

    2016-02-01

    Full Text Available This paper presents an optimal dispatch model of an ice storage air-conditioning system for participants to quickly and accurately perform energy saving and demand response, and to avoid the over contact with electricity price peak. The schedule planning for an ice storage air-conditioning system of demand response is mainly to transfer energy consumption from the peak load to the partial-peak or off-peak load. Least Squares Regression (LSR is used to obtain the polynomial function for the cooling capacity and the cost of power consumption with a real ice storage air-conditioning system. Based on the dynamic electricity pricing, the requirements of cooling loads, and all technical constraints, the dispatch model of the ice-storage air-conditioning system is formulated to minimize the operation cost. The Improved Ripple Bee Swarm Optimization (IRBSO algorithm is proposed to solve the dispatch model of the ice storage air-conditioning system in a daily schedule on summer. Simulation results indicate that reasonable solutions provide a practical and flexible framework allowing the demand response of ice storage air-conditioning systems to demonstrate the optimization of its energy savings and operational efficiency and offering greater energy efficiency.

  14. Sustainability Challenges from Climate Change and Air Conditioning Use in Urban Areas

    Directory of Open Access Journals (Sweden)

    Karin Lundgren

    2013-07-01

    Full Text Available Global climate change increases heat loads in urban areas causing health and productivity risks for millions of people. Inhabitants in tropical and subtropical urban areas are at especial risk due to high population density, already high temperatures, and temperature increases due to climate change. Air conditioning is growing rapidly, especially in South and South-East Asia due to income growth and the need to protect from high heat exposures. Studies have linked increased total hourly electricity use to outdoor temperatures and humidity; modeled future predictions when facing additional heat due to climate change, related air conditioning with increased street level heat and estimated future air conditioning use in major urban areas. However, global and localized studies linking climate variables with air conditioning alone are lacking. More research and detailed data is needed looking at the effects of increasing air conditioning use, electricity consumption, climate change and interactions with the urban heat island effect. Climate change mitigation, for example using renewable energy sources, particularly photovoltaic electricity generation, to power air conditioning, and other sustainable methods to reduce heat exposure are needed to make future urban areas more climate resilient.

  15. A simulation Model of the Reactor Hall Ventilation and air Conditioning Systems of ETRR-2

    International Nuclear Information System (INIS)

    Although the conceptual design for any system differs from one designer to another. each of them aims to achieve the function of the system required. the ventilation and air conditioning system of reactors hall is one of those systems that really differs but always dose its function for which it is designed. thus, ventilation and air conditioning in some reactor hall constitute only one system whereas in some other ones, they are separate systems. the Egypt Research Reactor-2 (ETRR-2)represents the second type. most studies conducted on ventilation and air conditioning simulation models either in traditional building or for research rectors show that those models were not designed similarly to the model of the hall of ETRR-2 in which ventilation and air conditioning constitute two separate systems.besides, those studies experimented on ventilation and air conditioning simulation models of reactor building predict the temperature and humidity inside these buildings at certain outside condition and it is difficult to predict when the outside conditions are changed . also those studies do not discuss the influences of reactor power changes. therefore, the present work deals with a computational study backed by infield experimental measurements of the performance of the ventilation and air conditioning systems of reactor hall during normal operation at different outside conditions as well as at different levels of reactor power

  16. Method for acquiring part load distribution coefficient of air conditioning system

    Institute of Scientific and Technical Information of China (English)

    丁勇; 李百战; 谭颖

    2009-01-01

    This paper presents a method to acquire runtime distribution ratio of building air conditioning system under part load condition (part load coefficient of system) through practical energy consumption data. By utilizing monthly energy consumption data of the entire year as the analysis object,this paper identifies data distribution,verifies distribution characteristics and analyzes distribution probability density for the issue of running time distribution ratio of air conditioning system in part load zones in the whole operation period,thus providing a basic calculation basis for an overall analysis of energy efficiency of air conditioning system. In view of the general survey of public building energy consumption carried by the government of Chongqing,this paper takes the governmental office building as an example,the part load ratio coefficient corresponding to practical running of air conditioning system of governmental office building in Chongqing is obtained by utilizing the above probability analysis and the solving method of probability density function. By utilizing the ratio coefficient obtained using this method,the part load coefficient with any running ratio of air conditioning system can be obtained according to the requirement of analysis,which can be used in any load ratio for analyzing running energy efficiency of air conditioning system.

  17. Cosmological Background torsion limits from Lorentz violation

    CERN Document Server

    Garcia de Andrade, L C

    2001-01-01

    Cosmological limits on Lorentz invariance breaking in Chern-Simons $(3+1)-dimensional$ electrodynamics are used to place limits on torsion. Birefrigence phenomena is discussed by using extending the propagation equation to Riemann-Cartan spacetimes instead of treating it in purely Riemannian spaces. The parameter of Lorentz violation is shown to be proportional to the axial torsion vector which allows us to place a limit on cosmological background torsion from the Lorentz violation constraint which is given by $ 10^{-33} eV <|S^{\\mu}| < 10^{-32} eV$ where $|S^{\\mu}|$ is the axial torsion vector.

  18. What Do We Know About Lorentz Invariance?

    CERN Document Server

    Tasson, Jay D

    2014-01-01

    The realization that Planck-scale physics can be tested with existing technology through the search for spacetime-symmetry violation brought about the development of a comprehensive framework, known as the gravitational Standard-Model Extension (SME), for studying deviations from exact Lorentz and CPT symmetry in nature. The development of this framework and its motivation led to an explosion of new tests of Lorentz symmetry over the past decade and to considerable theoretical interest in the subject. This work reviews the key concepts associated with Lorentz and CPT symmetry, the structure of the SME framework, and some recent experimental and theoretical results.

  19. Lorentz gauge quantization in synchronous coordinates

    CERN Document Server

    Garner, Christopher

    2016-01-01

    It has been shown that the Gupta-Bleuler method of quantization can be used to impose the Lorentz gauge condition in static space-times but not in cosmological space-times. This implies that the Gupta-Bleuler approach fails in general in non-static space-times. More recently, however, the Dirac method of quantizing constrained dynamical systems has been successfully employed to impose the Lorentz gauge in conformally flat space-times. In this paper we generalize this result by using Dirac's method to impose the Lorentz gauge in a general space-time region where the metric is expressed in synchronous coordinates.

  20. Test of Lorentz invariance with atmospheric neutrinos

    OpenAIRE

    collaboration, The Super-Kamiokande; :; Abe, K.; Haga, Y.; Hayato, Y.; Ikeda, M; Iyogi, K.; Kameda, J.; Kishimoto, Y.; Miura, M.; Moriyama, S.; Nakahata, M.(University of Tokyo, Institute for Cosmic Ray Research, Kamioka Observatory, Kamioka, Japan); Nakano, Y.; Nakayama, S.; Sekiya, H.

    2014-01-01

    A search for neutrino oscillations induced by Lorentz violation has been performed using 4,438 live-days of Super-Kamiokande atmospheric neutrino data. The Lorentz violation is included in addition to standard three-flavor oscillations using the non-perturbative Standard Model Extension (SME), allowing the use of the full range of neutrino path lengths, ranging from 15 to 12,800 km, and energies ranging from 100 MeV to more than 100 TeV in the search. No evidence of Lorentz violation was obse...

  1. Seeking Lorentz Violation from the Higgs

    CERN Document Server

    Cohen, Andrew; Xu, Yiming

    2014-01-01

    The recently discovered Higgs particle with a mass near $126$ GeV presents new opportunities to explore Lorentz violation. Ultra-high-energy cosmic rays are one of the most sensitive testing grounds for Lorentz symmetry, and can be used to seek for and limit departures from Lorentz invariance in the Higgs sector. If the Higgs were to have a super- or sub-luminal maximal speed both Higgs and weak interaction physics would be modified. Consideration of such modifications allow us to constrain the Higgs maximal velocity to agree with that of other Standard Model particles to parts in $10^{14}$.

  2. Fourth Meeting on CPT and Lorentz Symmetry

    Science.gov (United States)

    Kostelecký, V. Alan

    2008-03-01

    Improved tests of Lorentz and CPT symmetry using noble-gas masers / A. Glenday, D. F. Phillips, and R. L. Walsworth -- A modern Michelson-Morley experiment using actively rotated optical resonators / S. Herrmann et al. -- Rotating experiments to test Lorentz invariance in the photon sector / M. E. Tobar et al. -- Lorentz violation, electrodynamics, and the cosmic microwave background / M. Mewes -- High energy astrophysical tests of Lorentz invariance / B. Altschul -- Fundamental physics experiments in space (within ESA) / T. J. Sumner -- The experimental foundations of the Dirac equation / C. Lämmerzahl -- Perspectives on Lorentz and CPT violation / V. A. Kostelecký -- Search for Lorentz and CPT violation effects in muon spin precession / B. L. Roberts -- Lorentz violation in a diffeomorphism-invariant theory / R. Jackiw -- Studies of CPT symmetry with ASACUSA / R. S. Hayano -- Neutrino oscillations and Lorentz violation with MiniBooNE / R. Tayloe and T. Katori -- Testing Lorentz and CPT invariance with MINOS near detector neutrinos / B. J. Rebel and S. L. Mufson -- Einstein-ther gravity: theory and observational constraints / T. Jacobson -- Tests of Lorentz-invariance violation in neutrino oscillations / K. Whisnant -- Search for CPT violation in neutral kaons at KLOE: status and perspectives / A. Di Domenico et al. -- Search for CPT violation in B[symbol]-B¯[symbol] oscillations with BABAR / D. P. Stoker -- Theoretical topics in spacetime-symmetry violations / R. Lehnert -- A second-generation co-magnetometer for testing fundamental symmetries / S. J. Smullin et al. -- Nambu-Goldstone and massive modes in gravitational theories with spontaneous Lorentz breaking / R. Bluhm -- The ALPHA antihydrogen experiment / N. Madsen et al. -- Atom interferometry tests the isotropy of post-Newtonian gravity / H. Müller et al. -- Probing Lorentz symmetry with gravitationally coupled matter / J. D. Tasson -- Torsion balance test of preferred-frame and weak coupling to

  3. Energy-smart calculation of thermal loads in mobile and stationary heating, ventilation, air conditioning, and refrigeration systems

    OpenAIRE

    Fayazbakhsh, Mohammad Ali

    2015-01-01

    The energy consumption by heating, ventilation, air conditioning, and refrigeration systems forms a large portion of the total energy usage in buildings. Vehicle fuel consumption and emissions are also significantly affected by air conditioning. Air conditioning is also a critical system for hybrid electric vehicles and electric vehicles as the second most energy consuming system after the electric motor. Proper design and efficient operation of air conditioning systems require accurate calcu...

  4. Modified Lorentz transformations in deformed special relativity

    CERN Document Server

    Salesi, G; Deleidi, L; Peruzza, R A

    2016-01-01

    We extend a recent approach to Deformed Special Relativity based on deformed dispersion laws, entailing modified Lorentz transformations and, at the same time, noncommutative geometry and intrinsically discrete spacetime. In so doing we obtain the explicit form of the modified Lorentz transformations for a special class of modified momentum-energy relations often found in literature and arising from elementary particle physics. Actually, our theory looks as a very simple and natural extension of special relativity to include a momentum cut-off at the Planck scale. In particular, the new Lorentz transformations do imply that for high boost speed ($V \\sim c$) the deformed Lorentz factor does not diverge as in ordinary relativity, but results to be upperly bounded by a large finite value of the order of the ratio between the Planck mass and the particle mass. We also predict that a generic boost leaves unchanged Planck energy and momentum, which result invariant with respect to any reference frame.

  5. Lorentz violation. Motivation and new constraints

    Energy Technology Data Exchange (ETDEWEB)

    Liberati, S. [Scuola Internazionale Superiore di Studi Avanzati SISSA, Trieste (Italy); Istituto Nazionale di Fisica Nucleare INFN, Sezione di Trieste (Italy); Maccione, L. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-09-15

    We review the main theoretical motivations and observational constraints on Planck scale sup-pressed violations of Lorentz invariance. After introducing the problems related to the phenomenological study of quantum gravitational effects, we discuss the main theoretical frameworks within which possible departures from Lorentz invariance can be described. In particular, we focus on the framework of Effective Field Theory, describing several possible ways of including Lorentz violation therein and discussing their theoretical viability. We review the main low energy effects that are expected in this framework. We discuss the current observational constraints on such a framework, focusing on those achievable through high-energy astrophysics observations. In this context we present a summary of the most recent and strongest constraints on QED with Lorentz violating non-renormalizable operators. Finally, we discuss the present status of the field and its future perspectives. (orig.)

  6. Applications of Lorentz force in medical acoustics: Lorentz force hydrophone, Lorentz Force Electrical Impedance Tomography, Imaging of shear waves induced by Lorentz force

    CERN Document Server

    Grasland-Mongrain, Pol

    2014-01-01

    The ability of the Lorentz force to link a mechanical displacement to an electrical current presents a strong interest for medical acoustics, and three applications were studied in this thesis. In the first part of this work, a hydrophone was developed for mapping the particle velocity of an acoustic field. This hydrophone was constructed using a thin copper wire and an external magnetic field. A model was elaborated to determine the relationship between the acoustic pressure and the measured electrical current, which is induced by Lorentz force when the wire vibrates in the acoustic field of an ultrasound transducer. The built prototype was characterized and its spatial resolution, frequency response, sensitivity, robustness and directivity response were investigated. An imaging method called Lorentz Force Electrical Impedance Tomography was also studied. In this method, a biological tissue is vibrated by ultrasound in a magnetic field, which induces an electrical current by Lorentz force. The electrical imp...

  7. The Scientific Correspondence of H A Lorentz

    CERN Document Server

    Kox, AJ

    2008-01-01

    Presents a selection of more than 400 letters from and to the Dutch physicist and Nobel Prize winner Hendrik Antoon Lorentz (1853-1928), covering the period from 1883 until a few months before his death.

  8. Intelligent energy management control of vehicle air conditioning system coupled with engine

    International Nuclear Information System (INIS)

    Vehicle Air Conditioning (AC) systems consist of an engine powered compressor activated by an electrical clutch. The AC system imposes an extra load to the vehicle's engine increasing the vehicle fuel consumption and emissions. Energy management control of the vehicle air conditioning is a nonlinear dynamic system, influenced by uncertain disturbances. In addition, the vehicle energy management control system interacts with different complex systems, such as engine, air conditioning system, environment, and driver, to deliver fuel consumption improvements. In this paper, we describe the energy management control of vehicle AC system coupled with vehicle engine through an intelligent control design. The Intelligent Energy Management Control (IEMC) system presented in this paper includes an intelligent algorithm which uses five exterior units and three integrated fuzzy controllers to produce desirable internal temperature and air quality, improved fuel consumption, low emission, and smooth driving. The three fuzzy controllers include: (i) a fuzzy cruise controller to adapt vehicle cruise speed via prediction of the road ahead using a Look-Ahead system, (ii) a fuzzy air conditioning controller to produce desirable temperature and air quality inside vehicle cabin room via a road information system, and (iii) a fuzzy engine controller to generate the required engine torque to move the vehicle smoothly on the road. We optimised the integrated operation of the air conditioning and the engine under various driving patterns and performed three simulations. Results show that the proposed IEMC system developed based on Fuzzy Air Conditioning Controller with Look-Ahead (FAC-LA) method is a more efficient controller for vehicle air conditioning system than the previously developed Coordinated Energy Management Systems (CEMS). - Highlights: ► AC interacts: vehicle, environment, driver components, and the interrelationships between them. ► Intelligent AC algorithm which uses

  9. HUMAN RESOURCE MANAGEMENT PRACTICES IN REFRIGERATION AND AIR CONDITIONING INDUSTRY IN INDIA

    Directory of Open Access Journals (Sweden)

    Dr.Nisar Ahamad Nalband

    2010-11-01

    Full Text Available Over the last 150 years or so, refrigeration’s great strides offered us ways to preserve and cool food, other substances and ourselves. Refrigeration brought distant production centers. It tore down the barriers of climates and seasons. And while it helped to rev up industrial process, it became an industry itself It is understood that the refrigeration and air conditioning industry has been a promising industry for the development of Indian economy and one of the old industry in India too. Indian refrigeration and air conditioning Industry has been playing a very vital role in the growth of Indian economy. The employees of refrigeration and airconditioning Industry are mostly knowledge workers. Knowledge workers are skilled, use intuition and past experience, as well as creating the new knowledge which resides in their heads and which is also evident in their commitment, attitude and relationship. However, the projected growth of Indian refrigeration and air conditioning industry will largely depend upon the Industries’ ability to manage its human resources Though research has been done on HRD/HRM in refrigeration and air conditioning industry, a considerable study has yet to be made on Indian refrigeration and air conditioning industry. The literature on Indian refrigeration and air conditioning industry consists mainly in the form of Books, Annual Reports, and other web based reports. The Technical, Engineering and Management journals also published articles on the subject. A great amount of research work has to be carried on in the country. There is a promising and potential scope for the researchers to investigate more and inform more to Indian air conditioning and refrigeration industry to adapt to new techniques of HRM/HRD.

  10. Application of Computer Model to Estimate the Consistency of Air Conditioning Systems Engineering

    Directory of Open Access Journals (Sweden)

    Amal El-Berry

    2013-04-01

    Full Text Available Reliability engineering is utilized to predict the performance and optimization of the design and maintenance of air conditioning systems. There are a number of failures associated with the conditioning systems. The failures of an air conditioner such as turn on, loss of air conditioner cooling capacity, reduced air conditioning output temperatures, loss of cool air supply and loss of air flow entirely are mainly due to a variety of problems with one or more components of an air conditioner or air conditioning system. To maintain the system forecasting for system failure rates are very important. The focus of this paper is the reliability of the air conditioning systems. The most common applied statistical distributions in reliability settings are the standard (2 parameter Weibull and Gamma distributions. Reliability estimations and predictions are used to evaluate, when the estimation of distributionsparameters is done. To estimate good operating condition in a building, the reliability of the air conditioning system that supplies conditioned air to the several companies’ departments is checked. This air conditioning system is divided into two systems, namely the main chilled water system and the ten air handling systems that serves the ten departments. In a chilled-water system the air conditioner cools water down to 40 - 45oF (4 - 7oC. The chilled water is distributed throughout the building in a piping system and connected to air condition cooling units wherever needed. Data analysis has been done with support a computer aided reliability software, with the application of the Weibull and Gamma distributions it is indicated that the reliability for the systems equal to 86.012% and 77.7% respectively . A comparison between the two important families of distribution functions, namely, the Weibull and Gamma families is studied. It is found that Weibull method has performed well for decision making .

  11. DESIGN OF A VRF AIR CONDITIONING SYSTEM WITH ENERGY CONSERVATION ON COMMERCIAL BUILDING

    Directory of Open Access Journals (Sweden)

    Shaik Gulam Abul Hasan*

    2015-07-01

    Full Text Available Today, the field if air conditioning design is more technologically challenging than ever before. While design innovations and product improvements promise sleeker, more versatile, more powerful and more energy – efficient air conditioners, the challenge today lies identifying the most appropriate product, or mix of products, for the application at hand. Indeed, today the emphasis is no more on understanding air conditioning products but on creating solutions and not just solutions, but customized solutions that suit specific cooling need of specific business and establishments. The consultant or designer who understands the dynamics of those clients business is more likely to offer better long term cooling solutions than who does not. Every air conditioning application has its own special needs and provided its own challenges. Airports, hotels, shopping malls, office complexes and banks need uniform comfort cooling in every corner of their sprawling spaces and activities involving computers, electronics, aircraft products, precision manufacturing, communication networks and operation in hospitals, infect many areas of programming will come to a halt, so air conditioning is no longer a luxury but an essential part of modern living. There are various stages in the complete design of an air conditioning system. One of the important modules in the process is the duct design. The efficient duct design process enables the proper supply of air quantity, equal distribution of air at every corner of the Air conditioned space. Further the proper designing ensures minimum losses and hence energy conservation is obtained. In the present paper design of Air conditioning is done by using VRF (Variable Refrigerant Flow for a commercial building. The main aim of his project is to conserve the energy by using VRF techniques when compared to conventional chille

  12. On the generator of Lorentz boost

    Institute of Scientific and Technical Information of China (English)

    Wang Zhi-Yong; Xiong Cai-Dong

    2006-01-01

    Traditionally, the theory related to the spatial angular momentum has been studied completely, while the investigation in the generator of Lorentz boost is inadequate. This paper shows that the generator of Lorentz boost has a nontrivial physical significance: it endows a charged system with an electric moment, and has an important significance for the electrical manipulations of electron spin in spintronics. An alternative treatment and interpretation for the traditional Darwin term and spin-orbit coupling are given.

  13. Supersymmetry and Lorentz Violation in 5D

    International Nuclear Information System (INIS)

    We present a study for a Supersymmetric field theory with Lorentz-Violation terms in 5D. We perform the analysis in the context of the Berger-Kostelecky model (BK), adding one compactified dimension that explicitly breaks the Lorentz invariance. We introduce terms that encode this breaking, and find non trivial restrictions over boundary conditions of fields that one needs to close the supersymmetric algebra.

  14. Gauge anomalies in Lorentz-violating QED

    CERN Document Server

    Santos, Tiago R S

    2016-01-01

    In this work we study the issue of gauge anomalies in Lorentz-violating QED. To do so, we opt to use the BRST formalism within of the algebraic renormalization approach, reducing our study to a cohomology problem. Since that this approach is independent of the renormalization scheme, the results here obtained are expected to be general. We find that the Lorentz-violating QED is free of gauge anomalies to all orders in perturbation theory.

  15. Black Hole Thermodynamics and Lorentz Symmetry

    CERN Document Server

    Jacobson, Ted

    2008-01-01

    Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe the arguments leading to that conclusion. We suggest the implication that Lorentz symmetry should be viewed as an emergent property of the macroscopic world, required by the second law of black hole thermodynamics.

  16. Deduction of Lorentz Transformations from Classical Thermodynamics

    OpenAIRE

    Angela M. Ares de Parga; Fernado Angulo-Brown; Gonzalo Ares de Parga

    2015-01-01

    The Lorentz transformations are obtained by assuming that the laws of classical thermodynamics are invariant under changes of inertial reference frames. As Maxwell equations are used in order to deduce a wave equation that shows the constancy of the speed of light, by means of the laws of classical thermodynamics, the invariance of the Carnot cycle is deduced under reference frame changes. Starting with this result and the blackbody particle number density in a rest frame, the Lorentz transfo...

  17. Black Hole Thermodynamics and Lorentz Symmetry

    OpenAIRE

    Jacobson, Ted; Wall, Aron C.

    2008-01-01

    Recent developments point to a breakdown in the generalized second law of thermodynamics for theories with Lorentz symmetry violation. It appears possible to construct a perpetual motion machine of the second kind in such theories, using a black hole to catalyze the conversion of heat to work. Here we describe and extend the arguments leading to that conclusion. We suggest the inference that local Lorentz symmetry may be an emergent property of the macroscopic world with origins in a microsco...

  18. Investigation on thermal comfort response space and energy saving potential of summer air-conditioning system%夏季空调热舒适响应空间及节能潜力研究

    Institute of Scientific and Technical Information of China (English)

    雍静; 文充; 曾礼强

    2012-01-01

    Air-conditioning system as the power system user side of one high-power electrical equipment,heavy use of air conditioning system in summer has become the cause power shortage in the peak power one of the reasons. Paper to meet the requirements of human thermal comfort under the premise of air through the simulation of thermal comfort equation,established a comfortable air-conditioning system of space environment parameters and establish the parameters on the extent of comfort index. Through constructs the room cold load computation analysis to the air conditioning,confirmed the air-conditioning system to hare certain energy conservation potential in the thermal comfortable environment parameter space. Provide evidence for energy efficient operation of air conditioning system.%在满足人体热舒适要求的前提下,通过对空调热舒适方程的仿真分析,建立了空调系统环境参数的舒适空间,确立各参数对舒适性指标的影响程度;通过对空调建筑房间冷负荷计算分析,验证了空调系统在热舒适环境参数空间内存在一定节能潜力.

  19. Lorentz violations in multifractal spacetimes

    CERN Document Server

    Calcagni, Gianluca

    2016-01-01

    Using the recent observation of gravitational waves (GW) produced by a black-hole merger, we place a lower bound on the energy above which a multifractal spacetime would manifest an anomalous geometry and, in particular, violations of Lorentz invariance. In the so-called multifractional theory with $q$-derivatives, we show that the deformation of dispersion relations is much stronger than in generic quantum-gravity approaches (including loop quantum gravity) and, contrary to the latter, present observations on GWs can place very strong bounds on the characteristic scales at which spacetime deviates from standard Minkowski. The energy at which multifractal effects should become apparent is $E_*>10^{14}\\,\\text{GeV}$ (thus improving previous bounds by 12 orders of magnitude) when the exponents in the measure are fixed to their central value $1/2$. We also estimate, for the first time, the effect of logarithmic oscillations in the measure (corresponding to a discrete spacetime structure) and find that they do not...

  20. Refrigerating and air conditioning systems in the Republic of Macedonia regarding to the use of CFC fluids

    International Nuclear Information System (INIS)

    Classification of refrigerating systems and their condition in the Republic of Macedonia, by the capacity and application. Review of the subjects involved in refrigeration in the Republic of Macedonia: manufactures of refrigerating systems, distributors of refrigerating equipment, distributors of (CFC) refrigerants, maintenance and servicing of refrigerating systems regarding to the quality and the weak points. Measures and projects in the Republic of Macedonia in the field of the protection of the ozone layer. Regulations by the Montreal protocol. Regulations in the Republic of macedonia concerning refrigerating systems and CFC fluids in them. Country programme of the Republic of Macedonia and institutional activities. Projects in 'Frinko; and 'Sileks' where the manufacturing technologies are changed. Project 'Refrigerant management plan' in which are included: forming of training centers, training of service technicians and engineers involved in refrigeration and air conditioning, equipping of services and companies with on equipment for good practice in refrigeration and refrigerant's recovery, forming of recycling centers for purification of used refrigerants, training of custom officers. (Author)

  1. Lorentz microscopy mapping during magnetization process of L10 FePd thin films

    International Nuclear Information System (INIS)

    Lorentz Transmission Electron Microscopy (LTEM) allows the observation of magnetization evolution in thin magnetic layers. Electron Microscopy which enables observation at a nanometric scale is sensitive to magnetic induction perpendicular to the beam. Here we show that this technique allows the magnetization process in thin layers having perpendicular magnetic anisotropy to be studied. LTEM has been carried out on a JEOL 3010 and a FEI Titan 300kV (equipped with a Lorentz Lens). We determine how the magnetization is distributed along the domain walls (where the magnetization is in plane). Hence we could observe the evolution of a domain configuration during the magnetization process versus the orientation of its boundaries. This study is based on phase reconstruction methods and is completed by Lorentz image simulations.

  2. Air Conditioning Compressor Air Leak Detection by Image Processing Techniques for Industrial Applications

    Directory of Open Access Journals (Sweden)

    Pookongchai Kritsada

    2015-01-01

    Full Text Available This paper presents method to detect air leakage of an air conditioning compressor using image processing techniques. Quality of air conditioning compressor should not have air leakage. To test an air conditioning compressor leak, air is pumped into a compressor and then submerged into the water tank. If air bubble occurs at surface of the air conditioning compressor, that leakage compressor must be returned for maintenance. In this work a new method to detect leakage and search leakage point with high accuracy, fast, and precise processes was proposed. In a preprocessing procedure to detect the air bubbles, threshold and median filter techniques have been used. Connected component labeling technique is used to detect the air bubbles while blob analysis is searching technique to analyze group of the air bubbles in sequential images. The experiments are tested with proposed algorithm to determine the leakage point of an air conditioning compressor. The location of the leakage point was presented as coordinated point. The results demonstrated that leakage point during process could be accurately detected. The estimation point had error less than 5% compared to the real leakage point.

  3. Solar air conditioning: introduction and basics; Solare Klimatisierung Einfuehrung und Grundlagen

    Energy Technology Data Exchange (ETDEWEB)

    Albers, J. [Inst. fuer Erhaltung und Modernisierung von Bauwerken e.V. an der Technische Univ. Berlin (Germany)

    2005-07-01

    A considerable increase of the cold energy demand is expected world-wide in the coming years. Electrically operated cold compression plants are currently used at the most in order to meet the cold energy demand resulting also in a rising electric current and primary energy demand. This can have an effect on the supply security as well as on the change of the world climate. Therefore more alternative methods of cold generation are supposed to be applied in the future. The following contribution describes that plant systems for solar air conditioning (SAC-systems) are an attractive and feasible technology that demands engineering but can also be further developed and can make an important contribution to the target mentioned above. First an overview is provided of conventional air conditioning technology and of the expected development tendencies with regard to cold demand. Afterwards the currently available solar air conditioning methods and their possible applications are explained. (orig.)

  4. Numerical Analysis of Exergy for Air-Conditioning Influenced by Ambient Temperature

    Directory of Open Access Journals (Sweden)

    Jing-Nang Lee

    2014-07-01

    Full Text Available The article presents numerical analysis of exergy for air-conditioning influenced by ambient temperature. The model of numerical simulation uses an integrated air conditioning system exposed in varied ambient temperature to observe change of the four main devices, the compressor, the condenser, the capillary, and the evaporator in correspondence to ambient temperature. The analysis devices of the four devices’s exergy influenced by the varied ambient temperature and found that the capillary has unusual increasing exergy loss vs. increasing ambient temperature in comparison to the other devices. The result shows that reducing exergy loss of the capillary influenced by the ambient temperature is the key for improving working efficiency of an air-conditioning system when influence of the ambient temperature is considered. The higher ambient temperature causes the larger pressure drop of capillary and more exergy loss.

  5. An Expert Fault Diagnosis System for Vehicle Air Conditioning Product Development

    Science.gov (United States)

    Tan, C. F.; Tee, B. T.; Khalil, S. N.; Chen, W.; Rauterberg, G. W. M.

    2015-09-01

    The paper describes the development of the vehicle air-conditioning fault diagnosis system in automotive industries with expert system shell. The main aim of the research is to diagnose the problem of new vehicle air-conditioning system development process and select the most suitable solution to the problems. In the vehicle air-conditioning manufacturing industry, process can be very costly where an expert and experience personnel needed in certain circumstances. The expert of in the industry will retire or resign from time to time. When the expert is absent, their experience and knowledge is difficult to retrieve or lost forever. Expert system is a convenient method to replace expert. By replacing the expert with expert system, the accuracy of the processes will be increased compared to the conventional way. Therefore, the quality of product services that are produced will be finer and better. The inputs for the fault diagnosis are based on design data and experience of the engineer.

  6. Prediction of thermal sensation in non-air-conditioned buildings in warm climates

    DEFF Research Database (Denmark)

    Fanger, Povl Ole; Toftum, Jørn

    2002-01-01

    The PMV model agrees well with high-quality field studies in buildings with HVAC systems, situated in cold, temperate and warm climates, studied during both summer and winter. In non-air-conditioned buildings in warm climates, occupants may sense the warmth as being less severe than the PMV...... predicts. The main reason is low expectations, but a metabolic rate that is estimated too high can also contribute to explaining the difference. An extension of the PMV model that includes an expectancy factor is introduced for use in non-air-conditioned buildings in warm climates. The extended PMV model...... agrees well with quality field studies in non-air-conditioned buildings of three continents....

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

    Science.gov (United States)

    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.

  8. Extension of the PMV model to non-air-conditioned building in warm climates

    DEFF Research Database (Denmark)

    Fanger, Povl Ole; Toftum, Jørn

    2002-01-01

    The PMV model agrees well with high-quality field studies in buildings with HVAC systems, situated in cold, temperate and warm climates, studied during both summer and winter. In non-air-conditioned buildings in warm climates, occupants may sense the warmth as being less severe than the PMV...... predicts. The main reason is low expectations, but a metabolic rate that is estimated too high can also contribute to explaining the difference. An extension of the PMV model that includes an expectancy factor is introduced for use in non-air-conditioned buildings in warm climates. The extended PMV model...... agrees well with quality field studies in non-air-conditioned buildings of three continents....

  9. Air conditioning in a tropical climate: Impacts upon European residents in Darwin, Australia

    Science.gov (United States)

    Auliciems, A.; Dedear, R.

    1986-09-01

    The efficacy of current practices in air conditioning is investigated in the two monsoonal seasons in Darwin. Assessment is made of atmospheric parameters, clothing, metabolic rate. Some 1000 questionnaires are applied dealing with adaptations, health perceptions and preferences as related to air cooling and ventilation. The findings are discussed with reference to energy balance calculations and current models of psychological control in thermoregulation. The results indicate that Darwin's population is considerably overcooled, and contrary to assumptions and practice, air conditioning is not desired in office buildings during the “Dry”. In the home, air conditioning is not regarded as essential. The indications are that a rationalization of air cooling to comply with natural variability in warmth would lead to a significant reduction in energy consumption, and an overall enhancement to the health and comfort of the population through the greater ventilation rates that would be economically feasible were design temperatures lifted.

  10. Investigation on regeneration and energy storage characteristics of a solar liquid desiccant air-conditioning system

    Institute of Scientific and Technical Information of China (English)

    SHI Mingheng; DU Bin; ZHAO Yun

    2007-01-01

    Solar liquid desiccant air-conditioner is a new air-conditioning system in which liquid desiccant can be regenerated by solar energy and energy can be stored in the form of chemical energy in the liquid desiccant.In this paper regeneration and energy storage characteristics were studied theoretically and experimentally.Two criterion equations for heat and mass transfer in the regeneration process were obtained.The main factors that influence the regeneration process were analyzed.A principal solar liquid desiccant air-conditioning system under energy storage operating mode is proposed.

  11. Ice Storage Air-Conditioning System Simulation with Dynamic Electricity Pricing: A Demand Response Study

    OpenAIRE

    Chi-Chun Lo; Shang-Ho Tsai; Bor-Shyh Lin

    2016-01-01

    This paper presents an optimal dispatch model of an ice storage air-conditioning system for participants to quickly and accurately perform energy saving and demand response, and to avoid the over contact with electricity price peak. The schedule planning for an ice storage air-conditioning system of demand response is mainly to transfer energy consumption from the peak load to the partial-peak or off-peak load. Least Squares Regression (LSR) is used to obtain the polynomial function for the c...

  12. Lorentz-invariant ensembles of vector backgrounds

    International Nuclear Information System (INIS)

    We consider gauge field theories in the presence of ensembles of vector backgrounds. While Lorentz invariance is explicitly broken in the presence of any single background, here, the Lorentz invariance of the theory is restored by averaging over a Lorentz-invariant ensemble of backgrounds, i.e., a set of background vectors that is mapped onto itself under Lorentz transformations. This framework is used to study the effects of a non-trivial but Lorentz-invariant vacuum structure or mass dimension two vector condensates by identifying the background with a shift of the gauge field. Up to now, the ensembles used in the literature comprise configurations corresponding to non-zero field tensors together with such with vanishing field strength. We find that even when constraining the ensembles to pure gauge configurations, the usual high-energy degrees of freedom are removed from the spectrum of asymptotic states in the presence of said backgrounds in Euclidean and in Minkowski space. We establish this result not only for the propagators to all orders in the background and otherwise at tree level but for the full propagator

  13. Saving 50% of energy in air conditioning and refrigeration; 50% de ahorro de energia en aire acondicionado y refrigeracion

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez De la Fuente, Rodolfo Javier [Instituto para la Proteccion Ambiental de Nuevo Leon-CAINTRA, Nuevo Leon (Mexico); Bolado Tamez, Jaime Antonio [Industrias AlEn S. A. de C. V., Monterrey (Mexico)

    1998-12-31

    Due to the fact that the air conditioning systems represent up to 70% of the energy consumption in our buildings, to the constant raise of the electric tariffs and to the increment of temperatures in Nuevo Leon State, as well as the restrictions on the use of some refrigerant fluids because of its potential damage to the ozone layer (Montreal Protocol) and the preferential use of refrigerants with low global heating potential (Kioto Protocol). The Camara de la Industria de la Transformacion de Nuevo Leon (Nuevo Leon`s Transformation Industry Chamber) through the Instituto para la Proteccion Ambiental de Nuevo Leon (Nuevo Leon`s Institute for Environmental Protection), create the program ECO-REFRIGERATION whose three missions are: Increase the efficiency of air conditioning and refrigeration equipment, promote the substitution of refrigerants and extend the benefits of these projects to the community in general. [Espanol] Debido a que los sistemas de climatizacion representan hasta el 70% de consumo energetico en nuestros inmuebles, al constante incremento de las tarifas electricas, el incremento de las temperaturas en Nuevo Leon, asi como la restriccion del uso de algunos refrigerantes por su potencial de dano de la capa de ozono (Protocolo de Montreal) y el uso preferente de refrigerantes con bajo potencial de calentamiento global (Protocolo de Kioto), la Camara de la Industria de la Transformacion de Nuevo Leon a traves del Instituto para la Proteccion Ambiental de Nuevo Leon crean el Programa ECO-REFRIGERACION cuyas tres misiones son: Incrementar la eficiencia de los equipos de aire acondicionado y refrigeracion, promover la sustitucion de refrigerantes y extender los beneficios de este proyecto a la comunidad en general.

  14. Feasibility of a solar-assisted winter air-conditioning system using evaporative air-coolers

    Directory of Open Access Journals (Sweden)

    Mohamed M. El-Awad

    2011-03-01

    Full Text Available The paper presents a winter air-conditioning system which is suitable for regions with mildly cold but dry winters. The system modifies the evaporative air-cooler that is commonly used for summer air-conditioning in such regions by adding a heating process after the humidification process. The paper describes a theoretical model that is used to estimate the system's water and energy consumption. It is shown that a 150-LPD solar heater is adequate for air-conditioning a 500 ft3/min (14.4 m3/min air flow rate for four hours of operation. The maximum air-flow rate that can be heated by a single solar water-heater for four hours of operation is about 900-cfm, unless a solar water heater large than a 250-LPD heater is used. For the 500 ft3/min air flow rate the paper shows that the 150, 200, 250 and 300 LPD solar water-heaters can provide air-conditioning for 4, 6, 8 and 10 hours, respectively, while consuming less energy than the equivalent refrigerated-type air-conditioner.

  15. An energy performance assessment for indoor environmental quality (IEQ) acceptance in air-conditioned offices

    International Nuclear Information System (INIS)

    Maintaining an acceptable indoor environmental quality (IEQ) for air-conditioned office buildings consumes a considerable amount of thermal energy. This study correlates thermal energy consumption with the overall occupant acceptance of IEQ in some air-conditioned offices. An empirical expression of an IEQ index associated with thermal comfort, indoor air quality, aural and visual comfort is used to benchmark the offices. Employing input parameters obtained from the building stocks of Hong Kong, the office portfolios regarding the thermal energy consumption and the IEQ index are determined by Monte Carlo simulations. In particular, an energy-to-acceptance ratio and an energy-to-IEQ improvement ratio are proposed to measure the performance of energy consumption for the IEQ in the air-conditioned offices. The ratios give the thermal energy consumption corresponding to a desirable percentage of IEQ acceptances and to an IEQ upgrade, respectively. The results showed a non-linear increasing trend of annual thermal energy consumption for IEQ improvement at the offices of higher IEQ benchmarks. The thermal energy consumption for visual comfort and indoor air quality would also be significant in these offices. This study provides useful information that incorporates the IEQ in air-conditioned offices into the development of performance evaluation measures for thermal energy consumption.

  16. Research on performance of mixed absorption refrigeration for solar air-conditioning

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A novel lithium bromide/water mixed absorption refrigeration cycle that is suitable for the utilization of solar air-conditioning and can overcome the drawbacks of low system overall efficiency of traditional solar absorption refrigeration air-condition systems is presented.The accessorial high pressure generator was added in the cycle.The lithium bromide solution flowing out from the high pressure generator was mixed with the solution from the low pressure absorber to increase lithium bromide solution concentration and decrease pressure in the high pressure absorber.The performance of a mixed absorption refrigeration cycle was analyzed.The theoretical analysis shows that the highest COP is 0.61,while the highest available temperature difference of heat resource is 33.2℃.The whole coefficient of performance of the solar air-conditioning using mixed absorption cycle is 94.5% higher than that of two-stage absorption.The advantages of solar air-conditioning can be markedly made use of by the cycle.

  17. PIC (PRODUCTS OF INCOMPLETE COMBUSTION) FORMATION UNDER PYROLYTIC AND STARVED AIR CONDITIONS

    Science.gov (United States)

    A comprehensive program of laboratory studies based on the non-flame mode of thermal decomposition produced much data on PIC (Products of Incomplete Combustion) formation, primarily under pyrolytic and starved air conditions. Most significantly, laboratory results from non-flame ...

  18. Proceedings of the 1993 non-fluorocarbon insulation, refrigeration and air conditioning technology workshop

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    Sessions included: HFC blown polyurethanes, carbon dioxide blown foam and extruded polystyrenes, plastic foam insulations, evacuated panel insulation, refrigeration and air conditioning, absorption and adsorption and stirling cycle refrigeration, innovative cooling technologies, and natural refrigerants. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  19. Human requirements in future air-conditioned environments: a search for excellence

    DEFF Research Database (Denmark)

    Fanger, Povl Ole

    Although air-conditioning has played a positive role for economic development in warm climates, its image is globally mixed. Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from SBS symptoms, even though existing st...

  20. Application of Dual Throttling Air-Conditioning System to Explosion-Proof Frequency Converter

    Institute of Scientific and Technical Information of China (English)

    张于峰; 高岩; 盛颖

    2015-01-01

    An explosion-proof dual throttling air-conditioning system was put forward to solve the heat dissipation and internal dewing problems of explosion-proof frequency converter in the underground coal mine. This study inves-tigated the feasibility and benefits of explosion-proof dual throttling cooling and dehumidification air-conditioning system applied to the explosion-proof frequency converter. The physical model of dual throttling air-conditioning sys-tem was established and its performance parameter was described by mathematical method. The design calculation of the system has also been done. The experimental result showed that the system reached the steady state at the refrig-eration mode after running 45 min, and the maximum internal temperature of the flame-proof cavity was 31.0℃. The system reached the steady state at the dehumidification mode after running 37 min. The maximum internal relative humidity and temperature of the flame-proof cavity were 33.4% and 36.3 ℃, respectively. Therefore, the proposed system had excellent ability of heat dissipation and avoided internal dewing. Compared with water cooling system, it was more energy-saving and economical. The airflow field of dual throttling air-conditioning system was also studied by CFD simulation. It was found that the result of CFD numerical simulation was highly consistent with the experi-mental data.

  1. Performance of residential air-conditioning systems with flow maldistribution in fin-and-tube evaporators

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Brix, Wiebke; Elmegaard, Brian;

    2011-01-01

    Refrigerant and airflow maldistribution in fin-and-tube evaporators for residential air-conditioning was investigated with numerical modeling. Fin-and-tube heat exchangers usually have a pre-defined circuitry. However, the objective in this study was to perform a generic investigation of each...

  2. Optimal heat rejection pressure in transcritical carbon dioxide air conditioning and heat pump systems

    DEFF Research Database (Denmark)

    Liao, Shengming; Jakobsen, Arne

    1998-01-01

    Due to the urgent need for environmentally benign refrigerants, the use of the natural substance carbon dioxide in refrigeration systems has gained more and more attention. In systems such as automobile air-conditioners and heat pumps, owing to the relatively high heat rejection temperatures, the...... dioxide air conditioning or heat pump systems and for intelligent controlling such systems....

  3. 75 FR 6338 - Protection of Stratospheric Ozone: New Substitute in the Motor Vehicle Air Conditioning Sector...

    Science.gov (United States)

    2010-02-09

    ...EPA issued a proposed rule in the Federal Register of October 19, 2009, proposing to find HFO-1234yf acceptable, subject to use conditions as a substitute for CFC-12 in motor vehicle air conditioning. The proposed substitute is a non-ozone-depleting substance and consequently does not contribute to stratospheric ozone depletion. In response to requests from several stakeholders and to allow......

  4. Human requirements in future air-conditioned environments: a search for excellence

    DEFF Research Database (Denmark)

    Fanger, Povl Ole

    2000-01-01

    Although air-conditioning has played a positive role for economic development in warm climates, its image is globally mixed. Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from SBS symptoms, even though existing...

  5. Air-conditioning in the 21st century: impact on human productivity and energy consumption

    DEFF Research Database (Denmark)

    Fanger, Povl Ole

    2000-01-01

    Although air-conditioning has played a positive role for economic development in warm climates, its image is globally mixed. Field studies demonstrate that there are substantial numbers of dissatisfied people in many buildings, among them those suffering from Sick Building Syndrome (SBS) symptoms...

  6. Temperature and Humidity Independent Control Research on Ground Source Heat Pump Air Conditioning System

    Science.gov (United States)

    Chen, G.; Wang, L. L.

    Taking green demonstration center building air conditioning system as an example, this paper presents the temperature and humidity independent control system combined with ground source heat pump system, emphasis on the design of dry terminal device system, fresh air system and ground source heat pump system.

  7. Refrigeration and Air Conditioning Mechanic: Apprenticeship Course Outline. Apprenticeship and Industry Training. 1411.2

    Science.gov (United States)

    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,…

  8. Compensation of flow maldistribution in fin-and-tube evaporators for residential air-conditioning

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Brix, Wiebke; Elmegaard, Brian;

    2011-01-01

    Compensation of flow maldistribution in multi-channel fin-and-tube evaporators for residential air-conditioning is investigated by numerical modeling. The considered sources of maldistribution are distribution of the liquid and vapor phases in the distributor and non-uniform airflow distribution...

  9. Computerized Simulation of Automotive Air-Conditioning System: Development of Mathematical Model and Its Validation

    Directory of Open Access Journals (Sweden)

    Haslinda Mohamed Kamar

    2012-03-01

    Full Text Available A semi-empirical model for simulating thermal and energy performance of an automotive air-conditioning (AAC system in passenger vehicles has been developed. The model consists of two sections, namely empirical evaporator correlations and dynamic load simulation. The correlations used consider sensible and latent heat transfer performance of the evaporator coil. The correlations were obtained from the experimental data of actual air conditioning system for a compact size passenger car. The sensible heat transfer correlation relates the evaporator air off dry-bulb temperature to inlet air dry-bulb temperature, humidity ratio, evaporator air velocity, condenser inlet air dry-bulb temperature, condenser air velocity and compressor speed. The latent heat transfer correlation relates the coil air-off humidity ratio to the same six independent variables. The dynamic load simulation model was developed based on the z-transfer function method with a one-minute time step. The cooling load calculations were performed using heat gain weighting factors. Heat extraction rate and cabin air dry-bulb temperature calculations were carried out using air temperature weighting factors. The empirical evaporator sensible and latent heat transfer correlations were embedded in the loads calculation program to enable the determination of evaporator inlet and outlet air conditions, the cabin air temperature and relative humidity. Comparisons with road test data indicated that the program was capable of predicting the performance of the automotive air-conditioning system with reasonable accuracy.

  10. Heating, Air Conditioning and Refrigeration. Vocational Education Curriculum Guide. Industrial and Technical Education.

    Science.gov (United States)

    West Virginia State Vocational Curriculum Lab., Cedar Lakes.

    This curriculum guide contains 17 units that provides the basic curriculum components required to develop lesson plans for the heating, air conditioning, and refrigeration curriculum. The guide is not intended to be a complete, self-contained curriculum, but instead provides the teacher with a number of informational items related to the learning…

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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 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.

  13. Impact of climate change on commercial sector air conditioning energy consumption in subtropical Hong Kong

    International Nuclear Information System (INIS)

    Past and future trend of electricity use for air conditioning in the entire commercial sector in subtropical climates using 1979-2008 measured meteorological data as well as predictions for 2009-2100 from a general circulation model (MIROC3.2-H) was investigated. Air conditioning consumption showed an increasing trend over the past 30 years from 1979 to 2008. Principal component analysis (PCA) of measured and predicted monthly mean dry-bulb temperature, wet-bulb temperature and global solar radiation was conducted to determine a new climatic index Z for 1979-2008 and future 92 years (2009-2100) based on two emissions scenarios B1 and A1B (low and medium forcing). Through regression analysis, electricity use in air conditioning for the 92-year period was estimated. For low forcing, average consumption in 2009-2038, 2039-2068 and 2069-2100 would be, respectively, 5.7%, 12.8% and 18.4% more than the 1979-2008 average, with a mean 12.5% increase for the entire 92-year period. Medium forcing showed a similar increasing trend, but 1-4% more. Standard deviations of the monthly air conditioning consumption were found to be smaller suggesting possible reduction in seasonal variations in future years.

  14. Lorentz violation and black-hole thermodynamics

    International Nuclear Information System (INIS)

    We consider nonstandard photons from nonbirefringent modified Maxwell theory and discuss their propagation in a fixed Schwarzschild spacetime background. This particular modification of Maxwell theory is Lorentz-violating and allows for maximal photon velocities differing from the causal speed c of the asymptotic background spacetime. In the limit of geometrical optics, light rays from modified Maxwell theory are found to propagate along null geodesics in an effective metric. We observe that not every Lorentz-violating theory with multiple maximal velocities different from the causal speed c modifies the notion of the event horizon, contrary to naive expectations. This result implies that not every Lorentz-violating theory with multiple maximal velocities necessarily leads to a contradiction with the generalized second law of thermodynamics.

  15. Why is High Energy Physics Lorentz Invariant?

    CERN Document Server

    Afshordi, Niayesh

    2015-01-01

    Despite the tremendous empirical success of equivalence principle, there are several theoretical motivations for existence of a preferred reference frame (or aether) in a consistent theory of quantum gravity. However, if quantum gravity had a preferred reference frame, why would high energy processes enjoy such a high degree of Lorentz symmetry? While this is often considered as an argument against aether, here I provide three independent arguments for why perturbative unitarity (or weak coupling) of the Lorentz-violating effective field theories put stringent constraints on possible observable violations of Lorentz symmetry at high energies. In particular, the interaction with the scalar graviton in a consistent low-energy theory of gravity and a (radiatively and dynamically) stable cosmological framework, leads to these constraints. The violation (quantified by the relative difference in maximum speed of propagation) is limited to $\\lesssim 10^{-10} E({\\rm eV})^{-4}$ (superseding all current empirical bound...

  16. Test of Lorentz Invariance with Atmospheric Neutrinos

    CERN Document Server

    :,; Haga, Y; Hayato, Y; Ikeda, M; Iyogi, K; Kameda, J; Kishimoto, Y; Miura, M; Moriyama, S; Nakahata, M; Nakano, Y; Nakayama, S; Sekiya, H; Shiozawa, M; Suzuki, Y; Takeda, A; Tanaka, H; Tomura, T; Ueno, K; Wendell, R A; Yokozawa, T; Irvine, T; Kajita, T; Kametani, I; Kaneyuki, K; Lee, K P; McLachlan, T; Nishimura, Y; Richard, E; Okumura, K; Labarga, L; Fernandez, P; Gustafson, J; Kearns, E; Raaf, J L; Berkman, S; Tanaka, H A; Tobayama, S; Stone, J L; Sulak, L R; Goldhaber, M; Carminati, G; Kropp, W R; Mine, S; Weatherly, P; Renshaw, A; Smy, M B; Sobel, H W; Takhistov, V; Ganezer, K S; Hartfiel, B L; Hill, J; Keig, W E; Hong, N; Kim, J Y; Lim, I T; Akiri, T; Himmel, A; Scholberg, K; Walter, C W; Wongjirad, T; Ishizuka, T; Tasaka, S; Jang, J S; Learned, J G; Matsuno, S; Smith, S N; Hasegawa, T; Ishida, T; Ishii, T; Kobayashi, T; Nakadaira, T; Nakamura, K; Oyama, Y; Sakashita, K; Sekiguchi, T; Tsukamoto, T; Suzuki, A T; Takeuchi, Y; Bronner, C; Hirota, S; Huang, K; Ieki, K; Kikawa, T; Minamino, A; Murakami, A; Nakaya, T; Suzuki, K; Takahashi, S; Tateishi, K; Fukuda, Y; Choi, K; Itow, Y; Mitsuka, G; Mijakowski, P; Hignight, J; Imber, J; Jung, C K; Yanagisawa, C; Ishino, H; Kibayashi, A; Koshio, Y; Mori, T; Sakuda, M; Yamaguchi, R; Yano, T; Kuno, Y; Tacik, R; Kim, S B; Okazawa, H; Choi, Y; Nishijima, K; Koshiba, M; Suda, Y; Totsuka, Y; Yokoyama, M; Martens, K; Marti, Ll; Vagins, M R; Martin, J F; de Perio, P; Konaka, A; Wilking, M J; Chen, S; Zhang, Y; Connolly, K; Wilkes, R J

    2014-01-01

    A search for neutrino oscillations induced by Lorentz violation has been performed using 4,438 live-days of Super-Kamiokande atmospheric neutrino data. The Lorentz violation is included in addition to standard three-flavor oscillations using the non-perturbative Standard Model Extension (SME), allowing the use of the full range of neutrino path lengths, ranging from 15 to 12,800 km, and energies ranging from 100 MeV to more than 100 TeV in the search. No evidence of Lorentz violation was observed, so limits are set on the renormalizable isotropic SME coefficients in the $e\\mu$, $\\mu\\tau$, and $e\\tau$ sectors, improving the existing limits by up to seven orders of magnitude and setting limits for the first time in the neutrino $\\mu\\tau$ sector of the SME.

  17. Passive Lorentz transformations with spacetime algebra

    CERN Document Server

    Paiva, C R

    2005-01-01

    In special relativity spacetime algebra developed by David Hestenes, STA, provides a powerful and insightful approach to an invariant formulation of physics, the spacetime physics, through an elegant and concise manipulation of active Lorentz transformations. Therefore, it should come as an oddity, to say the least, to relate STA with passive Lorentz transformations. Nevertheless, length contraction, time dilation and all that are the bread and butter of most introductory courses on relativistic physics. To overcome the coordinate virus, it is necessary to be able to translate and dissolve passive Lorentz transformations in the fluidity and flexibility of STA, thereby bridging the gap between relativistic physics and proper spacetime physics. That is the aim of this paper.

  18. Looking for Lorentz violation with gravitational waves

    CERN Document Server

    Schreck, M

    2016-01-01

    The current letter has been inspired by the recent direct detection of gravitational waves reported by Advanced LIGO. In this context, a particular Lorentz-violating framework for classical, massive particles is on the focus. The latter is characterized by a preferred direction in spacetime comprised of CPT-odd components with mass dimension 1. Curvature effects in spacetime, which are caused by a propagating gravitational wave, are assumed to deform the otherwise constant background field. In accordance with spontaneous Lorentz violation, a particular choice for the vector field is taken, which was proposed elsewhere. The geodesic equations for a particle that is subject to this type of Lorentz violation are obtained. Subsequently, their numerical solutions are computed and discussed. The particular model considered leads to changes in the particle trajectory, which interferometric gravitational-wave experiments could be sensitive for. Since such effects have not been observed in the gravitational-wave event...

  19. On the Lorentz nature of confinement

    International Nuclear Information System (INIS)

    The Lorentz structure of the long-range confining force in the heavy quark approximation is studied within the model of QCD vacuum which is described by the bilocal gluonic correlators and assures the area law asymptotics for the isolated Wilson loop. The effective Dirac-type equation is written out for the quark propagating in such vacuum in the presence of static antiquark source. In the heavy quark limit the effective interaction is reduced to the potential one, with 5/6 Lorentz scalar and 1/6 Lorentz vector linear confinement. The next-to-leading in √(σ)/m corrections are calculated, and the sign and the coefficient at the spin-orbit term is found to be in agreement with both Eichten-Feinberg-Gromes results and demands of heavy quarkonia phenomenology

  20. Lorentz Abraham Force and Power Equations

    Science.gov (United States)

    Yaghjian, Arthur D.

    Toward the end of the nineteenth century Lorentz modeled the electron (“vibrating charged particle,” as he called it) by a spherical shell of uniform surface charge density and set about the difficult task of deriving the equation of motion of this electron model by determining, from Maxwell's equations and the Lorentz force law, the retarded self electromagnetic force that the fields of the accelerating charge distribution exert upon the charge itself [1]. (This initial work of Lorentz in 1892 on a moving charged sphere appeared five years before J.J. Thomson's “discovery” of the electron. It is summarized in English by J.Z. Buchwald [2, app. 7].) With the help of Abraham,1 a highly successful theory of the moving electron model was completed by the early 1900's [3, 4]. Before Einstein's papers [5, 6] on special relativity appeared in 1905, they had derived the following force equation of motion

  1. Aberration corrected Lorentz scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    We present results from an aberration corrected scanning transmission electron microscope which has been customised for high resolution quantitative Lorentz microscopy with the sample located in a magnetic field free or low field environment. We discuss the innovations in microscope instrumentation and additional hardware that underpin the imaging improvements in resolution and detection with a focus on developments in differential phase contrast microscopy. Examples from materials possessing nanometre scale variations in magnetisation illustrate the potential for aberration corrected Lorentz imaging as a tool to further our understanding of magnetism on this lengthscale. - Highlights: • Demonstration of nanometre scale resolution in magnetic field free environment using aberration correction in the scanning transmission electron microscope (STEM). • Implementation of differential phase contrast mode of Lorentz microscopy in aberration corrected STEM with improved sensitivity. • Quantitative imaging of magnetic induction of nanostructures in amorphous and cross-section samples

  2. Air-conditioning Australian households: The impact of dynamic peak pricing

    Energy Technology Data Exchange (ETDEWEB)

    Strengers, Yolande, E-mail: yolande.strengers@rmit.edu.a [Centre for Design, RMIT University, GPO Box 2476, Melbourne VIC 3001 (Australia)

    2010-11-15

    International mandates for smart metering are enabling variable and real-time pricing regimes such as dynamic peak pricing (DPP), which charges 10-40 times the off-peak rate for electricity during short periods. This regime aims to reduce peak electricity demand (predominantly due to increase in residential air-conditioning usage) and curb greenhouse gas emissions. Although trials indicate that DPP can achieve significant demand reductions, particularly in summer, little is known about how or why households change their cooling practices in response to this strategy. This paper discusses the outcomes of a small qualitative study assessing the impact of a DPP trial on household cooling practices in the Australian state of New South Wales. The study challenges common assumptions about the necessity of air-conditioning and impact of price signals. It finds that DPP engages households as co-managers of their cooling practices through a series of notification signals (SMS, phone, in-home display, email, etc.). Further, by linking the price signal to air-conditioning, some householders consider this practice discretionary for short periods of time. The paper concludes by warning that policy makers and utilities may serve to legitimise air-conditioning usage and/or negate demand reductions by failing to acknowledge the non-rational dynamics of DPP and household cooling practices. - Research highlights: {yields}Most householders consider air-conditioning discretionary during DPP events {yields}DPP engages householders as co-managers of their demand {yields}Notification of an upcoming DPP event is significant to the response {yields}Householders feel obligated to respond to DPP for a range of non-financial reasons

  3. Energy savings potential of a hybrid desiccant dehumidification air conditioning system in Beirut

    International Nuclear Information System (INIS)

    In this work, the transient performance of a hybrid desiccant vapor compression air conditioning system is numerically simulated for the ambient conditions of Beirut. The main feature of this hybrid system is that the regenerative heat needed by the desiccant wheel is partly supplied by the condenser dissipated heat while the rest is supplied by an auxiliary gas heater. The hybrid air conditioning system of the present study replaces a 23 kW vapor compression unit for a typical office in Beirut characterized by a high latent load. The vapor compression subsystem size in the hybrid air conditioning system is reduced to 15 kW at the peak load when the regeneration temperature was fixed at 75 deg. C. Also the sensible heat ratio of the combined hybrid system increased from 0.47 to 0.73. Based on hour by hour simulation studies for a wide range of recorded ambient conditions of Beirut city, this paper predicts the annual energy consumption of the hybrid system in comparison with the conventional vapor compression system for the entire cooling season. The annual running costs savings for the hybrid system is 418.39 USD for a gas cost price of 0.141 USD/kg. The pay back period of the hybrid system is less than five years when the initial cost of the hybrid air conditioning system priced an additional 1712.00 USD. Hence, for a 20-year life cycle, the life cycle savings of the hybrid air conditioning system are 4295.19 USD

  4. Air-conditioning and antibiotics: Demand management insights from problematic health and household cooling practices

    International Nuclear Information System (INIS)

    Air-conditioners and antibiotics are two technologies that have both been traditionally framed around individual health and comfort needs, despite aspects of their use contributing to social health problems. The imprudent use of antibiotics is threatening the capacity of the healthcare system internationally. Similarly, in Australia the increasing reliance on air-conditioning to maintain thermal comfort is contributing to rising peak demand and electricity prices, and is placing an inequitable health and financial burden on vulnerable heat-stressed households. This paper analyses policy responses to these problems through the lens of social practice theory. In the health sector, campaigns are attempting to emphasise the social health implications of antibiotic use. In considering this approach in relation to the problem of air-conditioned cooling and how to change the ways in which people keep cool during peak times, our analysis draws on interviews with 80 Australian households. We find that the problem of peak electricity demand may be reduced through attention to the social health implications of air-conditioned cooling on very hot days. We conclude that social practice theory offers a fruitful analytical route for identifying new avenues for research and informing policy responses to emerging health and environmental problems. - Highlights: • Over-use of antibiotics and air-conditioning has social health implications. • Focusing on financial incentives limits the potential of demand management programs. • Explaining peak demand to households shifts the meanings of cooling practices. • Emphasising the social health implications of antibiotics and air-conditioning may resurrect alternative practices. • Analysing policy with social practice theory offers insights into policy approaches

  5. Air-conditioning Australian households: The impact of dynamic peak pricing

    International Nuclear Information System (INIS)

    International mandates for smart metering are enabling variable and real-time pricing regimes such as dynamic peak pricing (DPP), which charges 10-40 times the off-peak rate for electricity during short periods. This regime aims to reduce peak electricity demand (predominantly due to increase in residential air-conditioning usage) and curb greenhouse gas emissions. Although trials indicate that DPP can achieve significant demand reductions, particularly in summer, little is known about how or why households change their cooling practices in response to this strategy. This paper discusses the outcomes of a small qualitative study assessing the impact of a DPP trial on household cooling practices in the Australian state of New South Wales. The study challenges common assumptions about the necessity of air-conditioning and impact of price signals. It finds that DPP engages households as co-managers of their cooling practices through a series of notification signals (SMS, phone, in-home display, email, etc.). Further, by linking the price signal to air-conditioning, some householders consider this practice discretionary for short periods of time. The paper concludes by warning that policy makers and utilities may serve to legitimise air-conditioning usage and/or negate demand reductions by failing to acknowledge the non-rational dynamics of DPP and household cooling practices. - Research highlights: →Most householders consider air-conditioning discretionary during DPP events →DPP engages householders as co-managers of their demand →Notification of an upcoming DPP event is significant to the response →Householders feel obligated to respond to DPP for a range of non-financial reasons

  6. Deduction of Lorentz Transformations from Classical Thermodynamics

    Directory of Open Access Journals (Sweden)

    Angela M. Ares de Parga

    2015-01-01

    Full Text Available The Lorentz transformations are obtained by assuming that the laws of classical thermodynamics are invariant under changes of inertial reference frames. As Maxwell equations are used in order to deduce a wave equation that shows the constancy of the speed of light, by means of the laws of classical thermodynamics, the invariance of the Carnot cycle is deduced under reference frame changes. Starting with this result and the blackbody particle number density in a rest frame, the Lorentz transformations are obtained. A discussion about the universality of classical thermodynamics is given.

  7. Testing Lorentz Symmetry using Chiral Perturbation Theory

    CERN Document Server

    Noordmans, J P

    2016-01-01

    We consider the low-energy effects of a selected set of Lorentz- and CPT-violating quark and gluon operators by deriving the corresponding chiral effective lagrangian. Using this effective lagrangian, low-energy hadronic observables can be calculated. We apply this to magnetometer experiments and derive the best bounds on some of the Lorentz-violating coefficients. We point out that progress can be made by studying the nucleon-nucleon potential, and by considering storage-ring experiments for deuterons and other light nuclei.

  8. Lorentz violation in simple QED processes

    CERN Document Server

    de Brito, G P; Kroff, D; Malta, P C; Marques, C

    2016-01-01

    We determine the effect of a CPT-even and Lorentz violating non-minimal coupling on the differential cross sections for some of the most important tree-level processes in QED, namely, Compton and Bhabha scatterings, as well as electron-positron annihilation. Experimental limits constraining the allowed deviation of the differential cross sections relative to pure QED allow us to place upper bounds on the Lorentz violating parameters. A constraint based on the decay rate of para-positronium is also obtained.

  9. Semilocal string with Lorentz-breaking term

    International Nuclear Information System (INIS)

    Full text: Topological defects arising from the spontaneous symmetry breaking are physical systems of interest in a wide range of theories, from condensed matter to cosmology. These defects may arise from an abelian, as well as non-abelian, symmetry spontaneously broken. The type of the defect depends on the broken symmetry. Among the typical interesting defects are the vortex solutions, whose characteristics were extensively investigated in the literature. On the other hand,extensions of the standard model including Lorentz-violation terms have been greatly studied in recent years. It was demonstrated that a Maxwell-Higgs systems with a CPT-even Lorentz symmetry violating term yields Bogomolnyi-Prasad-Sommerfield (BPS) vortex solutions enjoying fractional quantization of the magnetic field. One of the benchmarks of the vortex theory is the semi local vortex. Usually, most part of the study of vortex was restricted to the local symmetry. However, the inclusion of a global symmetry, besides the usual local one, may lead to some interesting characteristics in the resulting topological defect as the presence of topological vortex even if the vacuum manifold is simply connected. This work is partially concerned with the demonstration that semi local vortices may be found in a usual Maxwell-Higgs system plus a CPT-even Lorentz symmetry violating term. In fact, starting from a SU(2) global x U(1) local symmetry, the symmetry breaks down to U(1) local. Hence, the first homotopy group is trivial, i. e., π1(SU(2)globalxU(1)local=U(1)local) = 1. However, the local symmetry also plays its role. Since the potential we shall deal with goes as usual, it is possible to say that as in the usual Higgs-Maxwell case , when no Lorentz-violating term is present, the arguments in favor of stable vortices are strong, but not exhaustive. In order to guarantee the existence of semi local vortices in the Maxwell-Higgs plus Lorentz-violating model, we have to construct the solutions. It was

  10. The electrodeless Lorentz force (ELF) thruster experimental facility

    Science.gov (United States)

    Weber, T. E.; Slough, J. T.; Kirtley, D.

    2012-11-01

    An innovative facility for testing high-power, pulsed plasmoid thrusters has been constructed to develop the electrodeless Lorentz force (ELF) thruster concept. It is equipped with a suite of diagnostics optimized to study the physical processes taking place within ELF and evaluate its propulsive utility including magnetic field, neutral gas, and plasma flux diagnostics, a method to determine energy flow into the plasma from the pulsed power systems, and a new type of ballistic pendulum, which enables thrust to be measured without the need for installing the entire propulsion system on a thrust stand. Variable magnetic fields allow controlled studies of plume expansion in a small-scale experiment and dielectric chamber walls reduce electromagnetic influences on plasma behavior and thruster operation. The unique capabilities of this facility enable novel concept development to take place at greatly reduced cost and increased accessibility compared to testing at large user-facilities.

  11. Temperature and Humidity Control in Air-Conditioned Buildings with lower Energy Demand and increased Indoor Air Quality

    DEFF Research Database (Denmark)

    Paul, Joachim; Martos, E. T.

    2003-01-01

    Air-conditioning is not only a matter of temperature control. Thermal comfort and good indoor air quality are mainly a matter of humidity. Human health and well being may suffer seriously from inadequate humidity and/or too low temperatures in a room. A case study involving supermarket air-conditioning....... Binary Ice as secondary refrigerant for air-conditioning purposes is an economical and technically feasible solution in any climate. Whatever chilled water can do in an air-conditioning installation ? Binary Ice can do it better....

  12. Interpolation theorems on weighted Lorentz martingale spaces

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper several interpolation theorems on martingale Lorentz spaces are given.The proofs are based on the atomic decompositions of martingale Hardy spaces over weighted measure spaces.Applying the interpolation theorems,we obtain some inequalities on martingale transform operator.

  13. Extra dimensions and violations of Lorentz symmetry

    CERN Document Server

    Overduin, James M

    2016-01-01

    We use experimental limits on Lorentz violation to obtain new constraints on Kaluza-Klein-type theories in which the extra dimensions may be large but do not necessarily have units of length. The associated variation in fundamental quantities such as rest mass must occur slowly, on cosmological scales.

  14. Gravity, Lorentz violation, and the standard model

    International Nuclear Information System (INIS)

    The role of the gravitational sector in the Lorentz- and CPT-violating standard-model extension (SME) is studied. A framework is developed for addressing this topic in the context of Riemann-Cartan spacetimes, which include as limiting cases the usual Riemann and Minkowski geometries. The methodology is first illustrated in the context of the QED extension in a Riemann-Cartan background. The full SME in this background is then considered, and the leading-order terms in the SME action involving operators of mass dimension three and four are constructed. The incorporation of arbitrary Lorentz and CPT violation into general relativity and other theories of gravity based on Riemann-Cartan geometries is discussed. The dominant terms in the effective low-energy action for the gravitational sector are provided, thereby completing the formulation of the leading-order terms in the SME with gravity. Explicit Lorentz symmetry breaking is found to be incompatible with generic Riemann-Cartan geometries, but spontaneous Lorentz breaking evades this difficulty

  15. Diffusive limit for the random Lorentz gas

    OpenAIRE

    Nota, Alessia

    2014-01-01

    We review some recent results concerning the derivation of the diffusion equation and the validation of Fick's law for the microscopic model given by the random Lorentz Gas. These results are achieved by using a linear kinetic equation as an intermediate level of description between our original mechanical system and the diffusion equation.

  16. Quantum Lorentz and braided Poincare groups

    OpenAIRE

    Zakrzewski, S.

    1997-01-01

    Quantum Lorentz groups H admitting quantum Minkowski space V are selected. Natural structure of a quantum space G = V x H is introduced, defining a quantum group structure on G only for triangular H (q=1). We show that it defines a braided quantum group structure on G for |q|=1.

  17. The Lorentz Theory of Electrons and Einstein's Theory of Relativity

    Science.gov (United States)

    Goldberg, Stanley

    1969-01-01

    Traces the development of Lorentz's theory of electrons as applied to the problem of the electrodynamics of moving bodies. Presents evidence that the principle of relativity did not play an important role in Lorentz's theory, and that though Lorentz eventually acknowledged Einstein's work, he was unwilling to completely embrace the Einstein…

  18. Optimization of Selecting Air Conditioning Cold/Heat Sources with Grey Relation Analysis

    Institute of Scientific and Technical Information of China (English)

    CAO Guoqing; TU Guangbei

    2006-01-01

    Selection of air conditioning(AC) cold/heat sources generally concerns about certain aspects and cannot reveal the whole profile of the problems.Grey relation analysis (GRA) is a data processing method to categorize the correlation extent of compared sequences and a certain reference sequence in a system with uncertain information.It is applied to evaluating and selecting AC cold/heat sources from four main aspects, which are technology, economy, reliability, and operation and management.Case study shows that the result for selecting AC cold/heat sources with the GRA method can be more reasonable and convincible.Thus it offers a new approach for designers in heating, ventilating and air conditioning field to compare and evaluate different AC cold/heat sources.

  19. Private air conditioning systems - just a matter of conscience?; Ist eine private Klimaanlage nur eine Gewissensfrage?

    Energy Technology Data Exchange (ETDEWEB)

    Rogg, W. [NOK-Energieanwendung, Baden (Switzerland)

    1996-08-01

    Until recently, air conditioning systems in private buildings and single office rooms were an exception in this country rather than the rule, but it seems that the hot summer of 1995 brought about a change in this field. Confronted with the choice of raising their energy consumption and having to face the extreme heat, many house owners decided to install an air conditioning system. (orig.) [Deutsch] Bis vor kurzem bildeten Raumkuehlgeraete in Privathaushalten und Einzelbueros hierzulande eher die Ausnahme. Dies scheint seit dem letzten Sommer der Vergangenheit anzugehoeren, will man den Verkaufszahlen des Handels Glauben schenken. Im Gewissenskonflikt zwischen Energiesparen und Hitzekollaps moegen sich so manche schweissgeplagten Mitbuerger beim Kauf eines solchen Geraets in thermischer Notwehr befunden haben. (orig.)

  20. Ant-nest corrosion of copper tubing in air-conditioning units

    International Nuclear Information System (INIS)

    Ant-nest corrosion is a specific type of premature failure (2-3 months) of copper tubes used in air-conditioning units causing the loss of refrigerant liquid and the consequent environment pollution. It is known that attack requires the simultaneous presence of moisture, oxygen and a corrodent, usually an organic acid, such as formic, acetic propionic or butyric acid or other volatile organic substances like methanol, ethanol, formaldehyde or aceto aldehyde. Approximately 10% of all premature failures of copper tubes used in the heating, ventilation and air-conditioning (HVAC) industry are the results of ant-nest corrosion. This type of corrosion usually occurs in thin-wall copper pipes, especially when copper is de-sulphurised, and is known by several names: formicary corrosion, unusual corrosion, branched pits,pinhole corrosion, etc. (Author) 91 refs

  1. Development of a Ventilation and Air-conditioning System using Fixed Bed Desiccant Units

    Science.gov (United States)

    Miyazaki, Takahiko; Akisawa, Atsushi; Shindoh, Shinji; Masazumi, Godo; Takeshi, Takatsuka; Hamamoto, Yoshinori; Mori, Hideo

    The study investigated fixed bed desiccant units for ventilation and air-conditioning. The system mainly dehumidifies the outdoor fresh air to be supplied to an air-conditioned room. Hence, the airconditioning load of the air-conditioner in the room can be mitigated. Several adsorbents were compared from the viewpoints of humidity ratio at the outlet of the desiccant unit, dehumidified quantity per unit volume, and dehumidified quantity per unit adsorbent mass. The performance of the desiccant unit was predicted by simulation which was validated by comparison with experiment. The results revealed the most suitable adsorbent to reduce the desiccant unit size. It was also found that the humidity ratio at the outlet of the desiccant unit could be lowered by shortening the dimensionless switching time.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    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 absorption 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.

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

    Science.gov (United States)

    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. PMID:26413079

  4. Calculation of the Chilling Requirement for Air Conditioning in the Excavation Roadway

    Directory of Open Access Journals (Sweden)

    Yueping Qin

    2015-10-01

    Full Text Available To effectively improve the climate conditions of the excavation roadway in coal mine, the calculation of the chilling requirement taking air conditioning measures is extremely necessary. The temperature field of the surrounding rock with moving boundary in the excavation roadway was numerically simulated by using finite volume method. The unstable heat transfer coefficient between the surrounding rock and air flow was obtained via the previous calculation. According to the coupling effects of the air flow inside and outside air duct, the differential calculation mathematical model of air flow temperature in the excavation roadway was established. The chilling requirement was calculated with the selfdeveloped computer program for forecasting the required cooling capacity of the excavation roadway. A good air conditioning effect had been observed after applying the calculated results to field trial, which indicated that the prediction method and calculation procedure were reliable.

  5. Modeling of an Air Conditioning System with Geothermal Heat Pump for a Residential Building

    Directory of Open Access Journals (Sweden)

    Silvia Cocchi

    2013-01-01

    Full Text Available The need to address climate change caused by greenhouse gas emissions attaches great importance to research aimed at using renewable energy. Geothermal energy is an interesting alternative concerning the production of energy for air conditioning of buildings (heating and cooling, through the use of geothermal heat pumps. In this work a model has been developed in order to simulate an air conditioning system with geothermal heat pump. A ground source heat pump (GSHP uses the shallow ground as a source of heat, thus taking advantage of its seasonally moderate temperatures. GSHP must be coupled with geothermal exchangers. The model leads to design optimization of geothermal heat exchangers and to verify the operation of the geothermal plant.

  6. 2013 German refrigeration and air conditioning meeting. Proceedings; Deutsche Kaelte- und Klimatagung 2013. Tagungsbericht

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-07-01

    These proceedings cover the following main topics: cryoengineering - superconduction / energy storage; cryoapplications in biology and medicine; metrology; adsorption processes; condensation/evaporation; working fluids / simulation; ice production; plants and compressors; expansion and ejectors or recooling; use of cooling (passenger car air conditioning, supermarket); refrigerants; plant efficiency; emissions and legislation; air conditioning and use of heat pumps; air quality and control; building technology and block-type thermal power stations. [German] Dieser Tagungsbericht enthaelt folgende Themenschwerpunkte: Kryotechnik - Supraleitung/Energiespeicher; Kryoanwendungen in der Biologie und Medizin; Messtechnik; Adsorptionsprozesse; Kondensation/Verdampfung; Arbeitsfluide/Simulation; Eiserzeugung; Anlagen und Verdichter; Expansion und Ejektoren bzw. Rueckkuehlung; Kaelteanwendung (PKW-Klimatisierung; Supermarkt); Kaeltemittel; Anlageneffizienz; Emissionen und Gesetzgebung; Klimatechnik und Waermepumpenanwendung; Luftqualitaet und Regelung; Gebaeudetechnik und BHKW.

  7. An energy impact assessment of indoor air quality acceptance for air-conditioned offices

    International Nuclear Information System (INIS)

    Treatment of fresh air in ventilation systems for the air-conditioning consumes a considerable amount of energy and affects the indoor air quality (IAQ). The ventilation demand is primarily related to the occupant load. In this study, the ventilation demands due to occupant load variations and occupant acceptability were examined against certain IAQ objectives using the mass balance of carbon dioxide (CO2) concentrations in an air-conditioned office. In particular, this study proposed a ventilation model for the consideration of the occupant load variations and occupant acceptability based on the regional survey of typical offices (422 samples) in Hong Kong. The model was applied to evaluate the relative energy performance of different IAQ objectives in ventilation systems for typical office buildings in Hong Kong. The results showed that the energy consumption of a ventilation system would be correlated with the occupant load and acceptability in the air-conditioned office. Indicative CO2 levels of 800 ppmv, 1000 ppmv and 1200 ppmv corresponding to 83%, 97% and 99.7% survey samples were shown, corresponding to the thermal energy consumptions of 1500 MJ m-2 yr-1, 960 MJ m-2 yr-1and 670 MJ m-2 yr-1, respectively. In regards to the monetary issue, an annual value of HK$ 762 million per year in electrical consumption could be saved in all office buildings in Hong Kong when the indoor target CO2 concentration is increased from 1000 ppmv to 1200 ppmv. To achieve an excellent IAQ following the existing design standard, i.e. to decrease the CO2 level from 1000 ppmv to 800 ppmv, 56% additional energy would be consumed, corresponding to an annual value of HK$ 1,419 million, even though the occupant acceptability is only improved from 81% to 86%. The development of the models in this study would be useful for the energy performance evaluation of ventilation systems in air-conditioned offices

  8. The analysis and improvement of the humidity problem on air-condition system of SSRF

    International Nuclear Information System (INIS)

    In this work, efforts were made to solve the problem of high relative humidity in some areas of the Shanghai Synchrotron Radiation Facility (SSRF). Based on data analysis, theoretical demonstration and field tests, we found that the problem of high humidity was caused by two factors. The high humidity problem was solved by appropriate measures of keeping the actual operation load match to the design load of the air-conditioning systems and minimizing the outdoor air infiltration. (authors)

  9. Sustainability Challenges from Climate Change and Air Conditioning Use in Urban Areas

    OpenAIRE

    Karin Lundgren; Tord Kjellstrom

    2013-01-01

    Global climate change increases heat loads in urban areas causing health and productivity risks for millions of people. Inhabitants in tropical and subtropical urban areas are at especial risk due to high population density, already high temperatures, and temperature increases due to climate change. Air conditioning is growing rapidly, especially in South and South-East Asia due to income growth and the need to protect from high heat exposures. Studies have linked increased total hourly elect...

  10. Review on Conventional Air Conditioning, Alternative Refrigerants, and CO2 Heat Pumps for Vehicles

    OpenAIRE

    Moo-Yeon Lee; Dong-Yeon Lee

    2013-01-01

    With the reinforced ODP and GWP regulations, clean refrigerants including CO2, energy saving technology for fuel economy, especially focused on development and control strategy for the effective air conditioning system, and heat pump for vehicles have been widely investigated. Recently, the automotive CO2 heat pump for the next generation vehicles as an alternative to that of internal combustion engines has been evaluated and studied as a good option. In this paper, first part is reviewed on ...

  11. Preliminary thermodynamic design of a stirling cooler for mobile air conditioning systems : Technical report

    OpenAIRE

    Kaufmann, André; Ylinen, Hannu

    2015-01-01

    The present discussion on refrigerants used in mobile air conditioning (MAC) units leads to the question whether a stirling cycle based heat pump could replace the present technology. An experimental and simulative study is carried out to determine the design parameters of such a heat pump. It is found that the targeted power density cannot be reached with air as a working fluid. The power require-ments would lead to machine sizes too large for a passenger vehicle.

  12. Simulation and Optimization of a Solar Driven Air Conditioning System for Indian Cities

    OpenAIRE

    Sharma, Dev

    2013-01-01

    Simulation and Optimization of a Solar Driven Air Conditioning System for Indian Cities Conventional air-conditioners need high grade energy i.e. electricity, which in India, is primarily produced from fossil fuels. In spite of several emission restraints exercised by many countries under Kyoto protocol, energy consumption and pollution levels are higher than ever. Therefore, an assessment from the ecological point of view needs to be implemented as the greenhouse gases effect remains a threa...

  13. Performance Evaluation of an Air-Conditioning Compressor Part I: Measurement and Design Modeling

    OpenAIRE

    Thomas W. Bein; Yu-Tai Lee

    1999-01-01

    In order to comply with legislation to eliminate the use of refrigerants that damage the ozone layer, it is necessary to redesign centrifugal compressors, used by the US Navy for shipboard air-conditioning systems, to use an environmentally acceptable refrigerant. This paper describes an evaluation of a 125-ton compressor designed to use HCFC-124 as the refrigerant. The objectives are not only conducting the performance evaluation, but also pinpointing the design problems for achieving a high...

  14. R32 Compressor for Air conditioning and Refrigeration applications in China

    OpenAIRE

    Guo, Weihua; Ji, GaoFeng; Zhan, Honghong; Wang, Dan

    2012-01-01

    This paper evaluates the compressor performance and reliability impact by using R32 refrigerant for air conditioning (residential and commercial system); Performance and reliability impacts are compared with different popular refrigerants used in China, for example, R410A & R22 for AC. The design improvement on the scroll compressor will be discussed in order to reach required efficiency and reliability; these improvements include lubrication, internal heat management, motor design, and vapor...

  15. New principle of organization of working process of air conditioning systems at railway and sea transport

    OpenAIRE

    Andrey KRAJNIUK; Aleksander KRAJNIUK

    2008-01-01

    An indispensable component of ensuring safe control of railway and sea transport in conditions of hot climate is maintenance of comfortable temperature of air in control cabins and living spaces. Now the interest is restored to use the Air Refrigerating Plants (ARP) as they have a wide potential of low-temperature cooling without use of ozone-destructive cooling agents prohibited by decision of the Montreal meeting. At the same time, air conditioning installations on the basis of turbo-expand...

  16. Using Vibration Analysis to Determine Refrigerant Levels In an Automotive Air Conditioning System

    OpenAIRE

    Stasiunas, Eric Carl

    2002-01-01

    Presently, auto manufacturers do not have do not have efficient or accurate methods to determine the amount of refrigerant (R-134a) in an air conditioning system of an automobile. In the research presented, vibration analysis is examined as a possible method to determine this R-134a amount. Initial laboratory tests were completed and experimental modal analysis methods were investigated. This approach is based on the hypothesis that the natural frequency of the accumulator bott...

  17. Performance Evaluation of an Air-Conditioning Compressor Part II: Volute Flow Predictions

    OpenAIRE

    Yu-Tai Lee; Thomas W. Bein

    1999-01-01

    A numerical method that solves the Reynolds-averaged Navier-Stokes equations is used to study an inefficient component of a shipboard air-conditioning HCFC-124 compressor system. This high-loss component of the centrifugal compressor was identified as the volute through a series of measurements given in Part I of the paper. The predictions were made using three grid topologies. The first grid closes the connection between the cutwater and the discharge diffuser. The other two grids connect th...

  18. Heat pump air conditioning system for pure electric vehicle at ultra-low temperature

    OpenAIRE

    Li Hai-Jun; Zhou Guang-Hui; Li An-Gui; Li Xu-Ge; Li Ya-Nan; Chen Jie

    2014-01-01

    When the ordinary heat pump air conditioning system of a pure electric vehicle runs at ultra-low temperature, the discharge temperature of compressor will be too high and the heating capacity of the system will decay seriously, it will lead to inactivity of the heating system. In order to solve this problem, a modification is put forward, and an experiment is also designed. The experimental results show that in the same conditions, this new heating system i...

  19. A novel air-conditioning system for proactive power demand response to smart grid

    International Nuclear Information System (INIS)

    Highlights: • A novel air-conditioning system with proactive demand response is proposed. • The system can significantly reduce the storage volume of the chilled water tank. • Demand side bidding and demand as frequency controlled reserve can be implemented. • No impact on occupants when demand response is used in the proposed system. - Abstract: Power demand response is considered as one of the most promising solutions in relieving the power imbalance of an electrical grid that results a series of critical problems to the gird and end-users. In order to effectively make use of the demand response potentials of buildings, this paper presents a novel air-conditioning system with proactive demand control for daily load shifting and real time power balance in the developing smart grid. This system consists of a chilled water storage system (CWS) and a temperature and humidity independent control (THIC) air-conditioning system, which can significantly reduce the storage volume of the chilled water tank and effectively enable a building with more flexibility in changing its electricity usage patterns. The power demand of the proposed air-conditioning system can be flexibly controlled as desired by implementing two types of demand response strategies: demand side bidding (DSB) strategy and demand as frequency controlled reserve (DFR) strategy, in respond to the day-ahead and hour-ahead power change requirements of the grid, respectively. Considerable benefits (e.g., energy and cost savings) can be achieved for both the electricity utilities and building owners under incentive pricing or tariffs. A case study is conducted in a simulation platform to demonstrate the application of the proposed system in an office building

  20. Combination of experimental and simulated small scale solar air-conditioning system

    OpenAIRE

    Thomas, Sébastien; Hennaut, Samuel; Andre, Philippe

    2010-01-01

    It is now clearly assumed that solar assisted air conditioning is able to decrease CO2 production of building operation. One way to evaluate the energy savings potential is the simulation of airconditioning systems. On the other hand, it is also crucial to assess system performance by experimentations. The operation of a solar cooling system in its real environment is considered here. The objective is to evaluate if sun radiation in our region (Western Europe – Belgium) in summ...

  1. Application of an Integrated Heat Recovery Technology for Domestic Hot Water Supply System and Air Conditioning

    OpenAIRE

    Chen Yan; Zhang Yufeng

    2013-01-01

    This study is to design an integrated heat recovery and air conditioner system and to investigate the feasibility and the potential performance of this system in changing conditions. Different season conditions and operating modes are studied based on the items of one hotel. In winter, heat recovered from wastewater is used on water heating and air condition and the surplus energy of air conditioner system is used on hot water system in summer. Dynamic energy ...

  2. Ant-nest corrosion of copper tubing in air-conditioning units

    OpenAIRE

    Bastidas, D. M.; Cayuela, I.; Bastidas, J. M.

    2006-01-01

    Ant-nest corrosion is a specific type of premature failure (2-3 months) of copper tubes used in air-conditioning units causing the loss of refrigerant liquid and the consequent environment pollution. It is known that attack requires the simultaneous presence of moisture, oxygen and a corrodent, usually an organic acid, such as formic, acetic, propionic or butyric acid or other volatile organic substances like methanol, ethanol, formaldehyde or acetoaldehyde. Approximately 10% of all premature...

  3. Experimental and numerical study of an evaporatively-cooled condenser of air-conditioning systems

    International Nuclear Information System (INIS)

    The performance of an air-conditioning unit with evaporately-cooled condenser coil is studied experimentally and numerically. An experimental setup is fabricated by retrofitting a commercially available air-conditioning unit and installing comprehensive measuring sensors and controllers. Experimental result shows that the COP (Coefficient of Performance) of the evaporately-cooled air-conditioning unit increases by about 28% compared to the conventional air cooled air-conditioning unit. To analyze the heat and mass transfer processes involved in the evaporately-cooled condenser, a detailed theoretical model has been developed based on the fluid flow characteristics of the falling film and the thermodynamic aspect of the evaporation process. Simulated results agree well with experimental data. The numerical model provides new insights into the intrinsic links between operating variables and heat transfer characteristics of water film in evaluating the performance of evaporatively-cooled condenser system. Two heat transfer coefficients, namely, wall to bulk and bulk to interface are introduced and computed from the simulation results under different operating conditions. Finally, the overall heat transfer coefficient for the water film is computed and presented as a function of dimensionless variables which can conveniently be employed by engineers to design and analyze high performance evaporatively-cooled heat exchangers. - Highlights: • Performance of evaporatively-cooled condenser is investigated. • Local convective heat transfer coefficients of water film are determined. • Thermal resistance of water film is negligible. • Heat transfer with evaporated vapor plays significant role on performance. • Better condenser performance translates to an improvement in COP

  4. Impaired Air Conditioning within the Nasal Cavity in Flat-Faced Homo.

    Science.gov (United States)

    Nishimura, Takeshi; Mori, Futoshi; Hanida, Sho; Kumahata, Kiyoshi; Ishikawa, Shigeru; Samarat, Kaouthar; Miyabe-Nishiwaki, Takako; Hayashi, Misato; Tomonaga, Masaki; Suzuki, Juri; Matsuzawa, Tetsuro; Matsuzawa, Teruo

    2016-03-01

    We are flat-faced hominins with an external nose that protrudes from the face. This feature was derived in the genus Homo, along with facial flattening and reorientation to form a high nasal cavity. The nasal passage conditions the inhaled air in terms of temperature and humidity to match the conditions required in the lung, and its anatomical variation is believed to be evolutionarily sensitive to the ambient atmospheric conditions of a given habitat. In this study, we used computational fluid dynamics (CFD) with three-dimensional topology models of the nasal passage under the same simulation conditions, to investigate air-conditioning performance in humans, chimpanzees, and macaques. The CFD simulation showed a horizontal straight flow of inhaled air in chimpanzees and macaques, contrasting with the upward and curved flow in humans. The inhaled air is conditioned poorly in humans compared with nonhuman primates. Virtual modifications to the human external nose topology, in which the nasal vestibule and valve are modified to resemble those of chimpanzees, change the airflow to be horizontal, but have little influence on the air-conditioning performance in humans. These findings suggest that morphological variation of the nasal passage topology was only weakly sensitive to the ambient atmosphere conditions; rather, the high nasal cavity in humans was formed simply by evolutionary facial reorganization in the divergence of Homo from the other hominin lineages, impairing the air-conditioning performance. Even though the inhaled air is not adjusted well within the nasal cavity in humans, it can be fully conditioned subsequently in the pharyngeal cavity, which is lengthened in the flat-faced Homo. Thus, the air-conditioning faculty in the nasal passages was probably impaired in early Homo members, although they have survived successfully under the fluctuating climate of the Plio-Pleistocene, and then they moved "Out of Africa" to explore the more severe climates of

  5. Is fumigation enough for air conditioning units in operation theatres and Intensive care units?

    OpenAIRE

    Anasua Deb; Sharmila Raut; Sunita Gajbhiye; Priyanka Patil; Sanjay Raut

    2016-01-01

    Background: Strict asepsis is necessary in operating theatres (OT) and intensive care units (ICU) as the patients undergo invasive procedures. The filters of contaminated air conditioning (AC) units provide a niche for proliferation of fungi and production of fungal spores. Methods: The routine procedure for maintenance of sterile atmosphere in our hospital, i.e. fumigation and mopping walls with disinfectants often fail to address these fungal spores of the AC filters. We therefore carri...

  6. Simulation based energy consumption calculation of an office building using solar-assisted air conditioning

    OpenAIRE

    Thomas, Sébastien; Andre, Philippe

    2008-01-01

    To minimize environmental impact and CO2 production associated with air-conditioning system operation, it is reasonable to evaluate the prospects of a clean energy source. The targets of the study are to evaluate cooling energy consumption to maintain thermal comfort in an office building and to point out solar energy to satisfy these cooling needs. Simulations were carried out with three different cooling systems in the same operating conditions to determine as accurately as possible the pot...

  7. Impaired Air Conditioning within the Nasal Cavity in Flat-Faced Homo.

    Directory of Open Access Journals (Sweden)

    Takeshi Nishimura

    2016-03-01

    Full Text Available We are flat-faced hominins with an external nose that protrudes from the face. This feature was derived in the genus Homo, along with facial flattening and reorientation to form a high nasal cavity. The nasal passage conditions the inhaled air in terms of temperature and humidity to match the conditions required in the lung, and its anatomical variation is believed to be evolutionarily sensitive to the ambient atmospheric conditions of a given habitat. In this study, we used computational fluid dynamics (CFD with three-dimensional topology models of the nasal passage under the same simulation conditions, to investigate air-conditioning performance in humans, chimpanzees, and macaques. The CFD simulation showed a horizontal straight flow of inhaled air in chimpanzees and macaques, contrasting with the upward and curved flow in humans. The inhaled air is conditioned poorly in humans compared with nonhuman primates. Virtual modifications to the human external nose topology, in which the nasal vestibule and valve are modified to resemble those of chimpanzees, change the airflow to be horizontal, but have little influence on the air-conditioning performance in humans. These findings suggest that morphological variation of the nasal passage topology was only weakly sensitive to the ambient atmosphere conditions; rather, the high nasal cavity in humans was formed simply by evolutionary facial reorganization in the divergence of Homo from the other hominin lineages, impairing the air-conditioning performance. Even though the inhaled air is not adjusted well within the nasal cavity in humans, it can be fully conditioned subsequently in the pharyngeal cavity, which is lengthened in the flat-faced Homo. Thus, the air-conditioning faculty in the nasal passages was probably impaired in early Homo members, although they have survived successfully under the fluctuating climate of the Plio-Pleistocene, and then they moved "Out of Africa" to explore the more

  8. HUMAN RESOURCE MANAGEMENT PRACTICES IN REFRIGERATION AND AIR CONDITIONING INDUSTRY IN INDIA

    OpenAIRE

    Dr.Nisar Ahamad Nalband

    2010-01-01

    Over the last 150 years or so, refrigeration’s great strides offered us ways to preserve and cool food, other substances and ourselves. Refrigeration brought distant production centers. It tore down the barriers of climates and seasons. And while it helped to rev up industrial process, it became an industry itself It is understood that the refrigeration and air conditioning industry has been a promising industry for the development of Indian economy and one of the old industry in India too. I...

  9. Thermal comfort in air-conditioned mosques in the dry desert climate

    Energy Technology Data Exchange (ETDEWEB)

    Al-ajmi, Farraj F. [Department of Civil Engineering, College of Technological Studies, Shuwaikh 70654 (Kuwait)

    2010-11-15

    In Kuwait, as in most countries with a typical dry desert climate, the summer season is long with a mean daily maximum temperature of 45 C. Centralized air-conditioning, which is generally deployed from the beginning of April to the end of October, can have tremendous impact on the amount of electrical energy utilized to mechanically control the internal environment in mosque buildings. The indoor air temperature settings for all types of air-conditioned buildings and mosque buildings in particular, are often calculated based on the analytical model of ASHRAE 55-2004 and ISO 7730. However, a field study was conducted in six air-conditioned mosque buildings during the summers of 2007 to investigate indoor climate and prayers thermal comfort in state of Kuwait. The paper presents statistical data about the indoor environmental conditions in Kuwait mosque buildings, together with an analysis of prayer thermal comfort sensations for a total of 140 subjects providing 140 sets of physical measurements and subjective questionnaires were used to collect data. Results show that the neutral temperature (T{sub n}) of the prayers is found to be 26.1 C, while that for PMV is 23.3 C. Discrepancy of these values is in fact about 2.8 C higher than those predicted by PMV model. Therefore, thermal comfort temperature in Kuwait cannot directly correlate with ISO 7730 and ASHRAE 55-2004 standards. Findings from this study should be considered when designing air conditioning for mosque buildings. This knowledge can contribute towards the development of future energy-related design codes for Kuwait. (author)

  10. An Investigation Into Operating Strategy of Panasonic and LG Electronic in Chinas Air Conditioning Market

    OpenAIRE

    Kong, Wenzhou

    2006-01-01

    Abstract The dissertation investigates into operating strategy of Panasonic and LG Electronic in Chinas air conditioning market. It focuses on studying their entry modes, competitive strategy, and marketing strategy. Due to the characteristics of the study, qualitative research was chosen as research method. Data was collected mainly from published literature, textbooks, company annual report, interviews, and selected cases. The results of the research indicate both Panasonic and LG ...

  11. Auditing the European room air-conditioning systems and potential energy savings

    Energy Technology Data Exchange (ETDEWEB)

    Bory, Daniela; Adnot, Jerome; Greco, Carmelo; Marchio, Dominique [Ecole des Mines de Paris, Center for Energy and Processes (France)

    2007-07-01

    Nowadays, the European Community promotes the energy improvement of the air-conditioning (AC) systems through the compulsory inspection of these facilities in the frame of the Energy Performance of Buildings Directive [EPBD, 2002]. Inspection itself is just a motivating mean for the AC actors to improve the energy efficiency of the systems and reduce energy. Therefore, the aim of the inspection is to follow periodically the correct management of the facility through a quick visit of the plant and a study of the available documentation while the aim of the audit is the research of best efficiency improvements which requires further investigations to evaluate and quantify the savings. Audit differs from the common maintenance activities of the facilities, the aim of which is limited to guarantee the basic operation of the plant. There is an overall lack of methodologies specific for air-conditioning and the improvements proposed are seldom proven with scientific rigour. For room air conditioning systems, the impacts of defect during operation due to ageing and neglected maintenance are considered: fouled condenser, charge leaks, compressor performances reduced, fans degradation, filter fouling and additional pressure drop in liquid line are explored. The over consumption due to these defects is evaluated for different building types and French climates. The results allow to define simple methods that can be used by the auditors to estimate the energy savings due to the correction of the defects.

  12. Hospital-acquired infections associated with poor air quality in air-conditioned environments

    Directory of Open Access Journals (Sweden)

    Daniela Pinheiro da Silva

    2014-04-01

    Full Text Available Backgound and Objectives: Individuals living in cities increasingly spend more time indoors in air-conditioned environments. Air conditioner contamination can be caused by the presence of aerosols from the external or internal environment, which may be associated with disease manifestations in patients present in this type of environment. Therefore, the aim of this review was to assess the air quality in air-conditioned hospital environments as a risk factor for hospital-acquired infections – HAI – as the air can be a potential source of infection, as well as assess the exposure of professionals and patients to different pollutants. Material and Methods: A literature review was performed in the LILACS, MEDLINE, SCIELO, SCIENCE DIRECT databases, CAPES thesis database and Ministry of Health – Brazil, including studies published between 1982 and 2008. The literature search was grouped according to the thematic focus, as follows: ventilation, maintenance and cleaning of systems that comprehend the environmental quality standard. Discussion and Conclusion: Outbreaks of hospital-acquired infections associated with Aspergillus, Acinetobacter, Legionella, and other genera such as Clostridium and Nocardia, which were found in air conditioners, were observed, thus indicating the need for air-conditioning quality control in these environments.

  13. Energy and Greenhouse Gas Emission Assessment of Conventional and Solar Assisted Air Conditioning Systems

    Directory of Open Access Journals (Sweden)

    Xiaofeng Li

    2015-11-01

    Full Text Available Energy consumption in the buildings is responsible for 26% of Australia’s greenhouse gas emissions where cooling typically accounts for over 50% of the total building energy use. The aim of this study was to investigate the potential for reducing the cooling systems’ environmental footprint with applications of alternative renewable energy source. Three types of cooling systems, water cooled, air cooled and a hybrid solar-based air-conditioning system, with a total of six scenarios were designed in this work. The scenarios accounted for the types of power supply to the air-conditioning systems with electricity from the grid and with a solar power from highly integrated building photovoltaics (BIPV. Within and between these scenarios, systems’ energy performances were compared based on energy modelling while the harvesting potential of the renewable energy source was further predicted based on building’s detailed geometrical model. The results showed that renewable energy obtained via BIPV scenario could cover building’s annual electricity consumption for cooling and reduce 140 tonnes of greenhouse gas emissions each year. The hybrid solar air-conditioning system has higher energy efficiency than the air cooled chiller system but lower than the water cooled system.

  14. Tourists’ attitudes towards ban on smoking in air-conditioned hotel lobbies in Thailand

    Science.gov (United States)

    Viriyachaiyo, V; Lim, A

    2009-01-01

    Background: Thailand is internationally renowned for its stringent tobacco control measures. In Thailand, a regulation banning smoking in air-conditioned hotel lobbies was issued in late 2006, causing substantial apprehension within the hospitality industry. A survey of tourists’ attitudes toward the ban was conducted. Methods: A cross-sectional survey of 5550 travellers staying in various hotels in Bangkok, Surat Thani, Phuket, Krabi and Songkhla provinces, October 2005 to December 2006. Travellers aged 15 years or older with a check-in duration of at least one day and willing to complete the questionnaire were requested by hotel staff to fill in the 5-minute questionnaire at check-in or later at their convenience. Results: Secondhand cigarette smoke was recognised as harmful to health by 89.7% of respondents. 47.8% of travellers were aware of the Thai regulation banning smoking in air-conditioned restaurants. 80.9% of the respondents agreed with the ban, particularly female non-smokers. 38.6% of survey respondents indicated that they would be more likely to visit Thailand again because of the regulation, 53.4% that the regulation would not affect their decision and 7.9% that they would be less likely to visit Thailand again. Conclusion: Banning smoking in air-conditioned hotel lobbies in Thailand is widely supported by tourists. Enforcement of the regulation is more likely to attract tourists than dissuade them from holidaying in Thailand. PMID:19364754

  15. Residential solar air conditioning: Energy and exergy analyses of an ammonia–water absorption cooling system

    International Nuclear Information System (INIS)

    Large scale heat-driven absorption cooling systems are available in the marketplace for industrial applications but the concept of a solar driven absorption chiller for air-conditioning applications is relatively new. Absorption chillers have a lower efficiency than compression refrigeration systems, when used for small scale applications and this restrains the absorption cooling system from air conditioning applications in residential buildings. The potential of a solar driven ammonia–water absorption chiller for residential air conditioning application is discussed and analyzed in this paper. A thermodynamic model has been developed based on a 10 kW air cooled ammonia–water absorption chiller driven by solar thermal energy. Both energy and exergy analyses have been conducted to evaluate the performance of this residential scale cooling system. The analyses uncovered that the absorber is where the most exergy loss occurs (63%) followed by the generator (13%) and the condenser (11%). Furthermore, the exergy loss of the condenser and absorber greatly increase with temperature, the generator less so, and the exergy loss in the evaporator is the least sensitive to increasing temperature. -- Highlights: • 10 kW solar thermal driven ammonia–water air cooled absorption chiller is investigated. • Energy and exergy analyses have been done to enhance the thermal performance. • Low driving temperature heat sources have been optimized. • The efficiencies of the major components have been evaluated

  16. Possible schemes for solar-powered air-conditioning in 2-storey terrace houses

    International Nuclear Information System (INIS)

    Space cooling is required all year round in the tropics, and probably accounts for a considerable proportion of the cost of electricity. Solar radiation can be channeled into cooling by photovoltaic powered systems and through the relatively new adsorption cycle technology. Two-storey terrace housing appear to have the greatest potential of introducing solar-powered cooling to residential homes. There are two schemes to cool a two-storey terrace housing: 1) By spraying water down the roof a tank, circulated by a pump powered by PV panels on the roof or 2) By replacing the roof with solar hot water collectors and use adsorption cooling chillers to produce air-conditioning for the entire block of terrace houses. In scheme number 1, a preliminary, rough technical evaluation showed that it is possible to pump water to the roof to flow down as a thin film and cool the roof by evaporation to about 40 degree C from about 70 degree C if without water evaporation at the highest insolation rate of the day. Scheme number 2, which uses adsorption chilling technology, requires communal sharing of the air-conditioning facility. The effect of collecting solar heat using the roof is two fold: to absorb solar energy for producing hot water and reducing excess heat input to the house. Preliminary costing demonstrates that solar-powered air-conditioning is within reach of commercialisation, bearing in mind that bulk purchases will dramatically lower the price of a product

  17. Optimal Energy Reduction Schedules for Ice Storage Air-Conditioning Systems

    Directory of Open Access Journals (Sweden)

    Whei-Min Lin

    2015-09-01

    Full Text Available This paper proposes a hybrid algorithm to solve the optimal energy dispatch of an ice storage air-conditioning system. Based on a real air-conditioning system, the data, including the return temperature of chilled water, the supply temperature of chilled water, the return temperature of ice storage water, and the supply temperature of ice storage water, are measured. The least-squares regression (LSR is used to obtain the input-output (I/O curve for the cooling load and power consumption of chillers and ice storage tank. The objective is to minimize overall cost in a daily schedule while satisfying all constraints, including cooling loading under the time-of-use (TOU rate. Based on the Radial Basis Function Network (RBFN and Ant Colony Optimization, an Ant-Based Radial Basis Function Network (ARBFN is constructed in the searching process. Simulation results indicate that reasonable solutions provide a practical and flexible framework allowing the economic dispatch of ice storage air-conditioning systems, and offering greater energy efficiency in dispatching chillers.

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

    Science.gov (United States)

    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.

  19. Fault-tolerant supervisory control of VAV air-conditioning systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.-F.; Dexter, A. [Department of Engineering Science, University of Oxford, Oxford (United Kingdom)

    2001-07-01

    The paper describes a supervisory control scheme that adapts to the presence of degradation faults and minimises any resulting increase in energy consumption or deterioration in occupant comfort. Since there is a high degree of uncertainty associated with the results of any fault identification scheme in information-poor systems of this type, the supervisory control scheme uses fuzzy models to predict the control performance and a computationally undemanding optimisation scheme to determine the most appropriate set-points. The fault-tolerant control scheme is developed and evaluated using a detailed computer simulation of a multi-zone, variable-air-volume (VAV), air-conditioning system. The fuzzy models relate the performance of the terminal-boxes, the air-handling unit and the chiller to fuzzy descriptions of the cooling load, the supply air and chilled water temperature set-points, and the amount of air-side and water-side fouling. Results are presented that demonstrate the ability of the fuzzy models to predict the performance and show how the power consumption of the air-conditioning system varies with set-point changes and the presence of both water-side and air-side fouling. The main factors that determine the suitability of a particular air-conditioning system for fault-tolerant control are also discussed. (author)

  20. 'TEWI' concept for estimation of the global warming from the refrigerating and air conditioning systems

    International Nuclear Information System (INIS)

    The most applied CFC refrigerants and their HFC alternatives. values of ODP (Ozone Depletion Potential) and GWP (Global Warming Potential) of the most used refrigerants. natural working fluids and their properties. Montreal Protocol and Kyoto Protocol, illogical relations between them concerning to the HFC fluids. Confusion and polemics on the international level about the appliance of HFCs which, by the Kyoto Protocol, are liable to reduction. Introduction of the TEWI concept as a method for estimating the overall influence of refrigerating and air conditioning systems on the greenhouse effect: the direct emission (refrigerant leakage in the atmosphere) and indirect emission as a result of the electrical energy consumption. A demonstration of the TEWI concept on the concrete example in several variants. A discussion about the appliance of the TEWI concept. Meaning of the energy efficiency of the refrigerating systems (indirect CO2 emission). One of the main measures: prevention of refrigerant leakage (direct CO2 emission). A need of permanent education and training courses of the people who work on refrigerating and air conditioning systems. A necessity for constitution of an expert body in the country, preparation of a strategy to lay obligations on the new changes of the Kyoto Protocol and news on the world market. Introduction of country regulations, certification of the companies and people involved in refrigeration and air conditioning. (Author)

  1. Local Lorentz transformations and Thomas effect in general relativity

    CERN Document Server

    Silenko, Alexander J

    2016-01-01

    The tetrad method is used for an introduction of local Lorentz frames and a detailed analysis of local Lorentz transformations. A formulation of equations of motion in local Lorentz frames is based on the Pomeransky-Khriplovich gravitoelectromagnetic fields. These fields are calculated in the most important special cases and their local Lorentz transformations are determined. The local Lorentz transformations and the Pomeransky-Khriplovich gravitoelectromagnetic fields are applied for a rigorous derivation of a general equation for the Thomas effect in Riemannian spacetimes and for a consideration of Einstein's equivalence principle and the Mathisson force.

  2. The natural gas air-conditioning; La climatisation au gaz naturel. Un avenir prometteur, une technique confirmee

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The natural gas air-conditioning market is in growth (it will cover 10% of the market in 2002).To illustrate the possibilities of this energy source, this paper presents three examples of the natural gas air-conditioning in France. The technical aspects, the cost and the advantages of such systems are discussed. (A.L.B.)

  3. SUMMARY OF ELECTRIC SERVICE COSTS FOR TOTALLY AIR CONDITIONED SCHOOLS PREPARED FOR HOUSTON INDEPENDENT SCHOOL DISTRICT, MAY 31, 1967.

    Science.gov (United States)

    WHITESIDES, M.M.

    THIS REPORT IS A COMPILATION OF DATA ON ELECTRIC AIR CONDITIONING COSTS, OPERATIONS AND MAINTENANCE. AIR CONDITIONING UNITS ARE COMPARED IN TERMS OF ELECTRIC VERSUS NON-ELECTRIC, AUTOMATIC VERSUS OPERATED, AIR COOLED VERSUS WATER COOLED, RECIPROCATING VERSUS CENTRIFUGAL COMPRESSORS, SPACE AND NOISE, REHEAT, MAINTENANCE AND ORIGINAL COST. DATA ARE…

  4. Top quality or poor quality of air-conditioning systems; Topkoeling of tobkoeling (beperkte koeling) van airconditioninginstallaties

    Energy Technology Data Exchange (ETDEWEB)

    Havenaar, D. (ed.)

    2003-09-01

    Due to savings on investments of air conditioning equipment those installations are designed and built with lesser cooling and ventilation capacity than required. The end user is confronted with an installation that does not meet the required capacity. This results in complaints about failures of required temperature and humidity levels. A bad air quality (high-CO2 level) caused by insufficient ventilation is another consequence. In that case the original top quality design turns out to be a disappointing miscalculation. [Dutch] Onder invloed van bezuinigingen op de investering wordt er vaak een airconditioninginstallatie geinstalleerd met een geringer koelvermogen dan volgens de koellastberekening inclusief de benodigde luchtverversing is berekend. De eindgebruiker ervaart dan achteraf dat de installatie niet voldoet aan de gestelde eisen. Klachten dat de gewenste temperatuur niet wordt behaald, te hoge luchtvochtigheid en bedompte lucht (CO2-aandeel te hoog) door onvoldoende luchtverversing zijn dan het gevolg. Van een oorspronkelijk ontworpen installatie met de kwalificatie top-koeling is er een installatie geleverd onder de categorie tob-koeling.

  5. Search for anisotropic Lorentz invariance violation with {\\gamma}-rays

    CERN Document Server

    Kislat, Fabian

    2015-01-01

    While Lorentz invariance, the fundamental symmetry of Einstein's theory of General Relativity, has been tested to a great level of detail, Grand Unified Theories that combine gravity with the other three fundamental forces may result in a violation of Lorentz symmetry at the Planck scale. These energies are unattainable experimentally. However, minute deviations from Lorentz invariance may still be present at much lower energies. These deviations can accumulate over large distances, making astrophysical measurements the most sensitive tests of Lorentz symmetry. One effect of Lorentz invariance violation is an energy dependent photon dispersion of the vacuum resulting in differences of the light travel time from distant objects. The Standard-Model Extension (SME) is an effective theory to describe the low-energy behaviour of a more fundamental Grand Unified Theory, including Lorentz and CPT violating terms. In the SME the Lorentz violating operators can in part be classified by their mass-dimension d, with the...

  6. IEA SHC Task 38 'Solar air-conditioning and refrigeration'. Danish participation 2007-2010; IEA SHC Task 38 'Solar air-conditioning and refrigeration'. Dansk deltagelse 2007-2010

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, Aarhus (Denmark)); Muenster, E. (PlanEnergi, Skoerping (Denmark)); Reinholdt, L. (Teknologisk Institut, Aarhus (Denmark)); Minds, S. (AC-Sun Aps, Horsens (Denmark))

    2011-03-15

    Skive City Hall. The Technological Institute has participated closely in preparing the report for subtask A 'Small Systems'. Furthermore The Technological Institute had the role as coordinator of activities around the optimization of 'heat rejection'. In this context it is especially the derived electricity for pumps and fans in the heat emitter (cooling tower, dry cooler, etc.) that are looked at. Traditionally heat driven refrigeration machines are controlled by regulating the driving heat flow (lower regeneration temperature). This has however, for most types of sys-tems, negative impact on the system efficiency and thus the power consumption of auxiliary equipment. This has led to the development of an alternative regulation strategy tested at Skive City Hall plant. In 2009 it was planned to attach adiabatic pre-cooling of the air cooling coils at Skive City Hall, however the solution proved to be quite expensive. Further optimization of the solution was therefore not implemented. The study of adiabatic pre-cooling was instead made in a laboratory setting at the Technological Institute. This was combined with the test of a new air cooling system, based on indirect evaporation of water. The test was conducted on a cooler purchased from the Netherlands and a MST project was demonstrating this technology to heat driven air conditioning in a supermarket. AC Sun has designed and produced an optimized prototype 2 and begun data collection. Prototype (2) is flexibly designed for testing different bearing solutions. The prototype is installed in a buffer tank connected to the heating elements as external heat source acting as a collector. Prototype 2 will be used as the final internal testing station before the final design and manufacture of test facilities for 'field' test in 5 test stations Denmark, Germany, Italy, Spain and Malaysia, respectively. Most of the testing stations are expected operating in spring 2011. Ellehauge and Kildemoes

  7. Hiding Lorentz Invariance Violation with MOND

    CERN Document Server

    Sanders, R H

    2011-01-01

    Ho\\v{r}ava gravity is a attempt to construct a renormalizable theory of gravity by breaking the Lorentz Invariance of the gravitational action at high energies. The underlying principle is that Lorentz Invariance is an approximate symmetry and its violation by gravitational phenomena is somehow hidden to present limits of observational precision. Here I point out that a simple modification of the low energy limit of Ho\\v{r}ava gravity in its non-projectable form can effectively camouflage the presence of a preferred frame in regions where the Newtonian gravitational field gradient is higher than $cH_0$; this modification results in the phenomenology of MOND at lower accelerations.

  8. Hiding Lorentz invariance violation with MOND

    International Nuclear Information System (INIS)

    Horava-Lifshitz gravity is an attempt to construct a renormalizable theory of gravity by breaking the Lorentz invariance of the gravitational action at high energies. The underlying principle is that Lorentz invariance is an approximate symmetry and its violation by gravitational phenomena is somehow hidden to present limits of observational precision. Here I point out that a simple modification of the low-energy limit of Horava-Lifshitz gravity in its nonprojectable form can effectively camouflage the presence of a preferred frame in regions where the Newtonian gravitational field gradient is higher than cH0; this modification results in the phenomenology of modified Newtonian dynamics (MOND) at lower accelerations. As a relativistic theory of MOND, this modified Horava-Lifshitz theory presents several advantages over its predecessors.

  9. Maxwell Duality, Lorentz Invariance, and Topological Phase

    CERN Document Server

    Dowling, J P; Franson, J D; Dowling, Jonathan P.; Williams, Colin P.

    1999-01-01

    We discuss the Maxwell electromagnetic duality relations between the Aharonov-Bohm, Aharonov-Casher, and He-McKellar-Wilkens topological phases, which allows a unified description of all three phenomena. We also elucidate Lorentz transformations that allow these effects to be understood in an intuitive fashion in the rest frame of the moving quantum particle. Finally, we propose a realistic set up for measuring and interpreting the He-McKellar-Wilkens phase directly in an experiment.

  10. Deviations from Fick's law in Lorentz gases

    OpenAIRE

    Lowe, C.P.; Frenkel, D.; van der Hoef, M. A.

    1997-01-01

    We have calculated the self-dynamic structure factorF(k,t) for tagged particle motion in hopping Lorentz gases. We find evidence that, even at long times, the probability distribution function for the displacement of the particles is highly non-Gaussian. At very small values of the wave vector this manifests itself as the divergence of the Burnett coefficient (the fourth moment of the distribution never approaching a value characteristic of a Gaussian). At somewhat larger wave vectors we find...

  11. Area spectrum in Lorentz covariant loop gravity

    OpenAIRE

    Alexandrov, S.; Vassilevich, D.

    2001-01-01

    We use the manifestly Lorentz covariant canonical formalism to evaluate eigenvalues of the area operator acting on Wilson lines. To this end we modify the standard definition of the loop states to make it applicable to the present case of non-commutative connections. The area operator is diagonalized by using the usual shift ambiguity in definition of the connection. The eigenvalues are then expressed through quadratic Casimir operators. No dependence on the Immirzi parameter appears.

  12. Area spectrum in Lorentz covariant loop gravity

    International Nuclear Information System (INIS)

    We use the manifestly Lorentz covariant canonical formalism to evaluate eigenvalues of the area operator acting on Wilson lines. To this end we modify the standard definition of the loop states to make it applicable to the present case of noncommutative connections. The area operator is diagonalized by using the usual shift ambiguity in the definition of the connection. The eigenvalues are then expressed through quadratic Casimir operators. No dependence on the Immirzi parameter appears

  13. The Lorentz anomaly via operator product expansion

    International Nuclear Information System (INIS)

    The emergence of a critical dimension is one of the most striking features of string theory. One way to obtain it is by demanding closure of the Lorentz algebra in the light-cone gauge quantisation, as discovered for bosonic strings more than forty years ago. We give a detailed derivation of this classical result based on the operator product expansion on the Lorentzian world-sheet

  14. Lorentz angle measurements in silicon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, V.; Boer, W. de E-mail: wim.de.boer@cern.ch; Bol, J.; Dierlamm, A.; Grigoriev, E.; Hauler, F.; Heising, S.; Herz, O.; Jungermann, L.; Keraenen, R.; Koppenhoefer, M.; Roederer, F.; Schneider, T

    2002-02-01

    In this paper we study the Lorentz angles of both electrons and holes in magnetic fields up to 8 T and temperatures between 77 and 300 K. This is done before and after irradiating a detector with 21 MeV protons up to a fluence of 10{sup 13}/cm{sup 2}, which is equivalent to {approx}2.8x10{sup 13}/cm{sup 2} 1 MeV neutrons.

  15. The Lorentz anomaly via operator product expansion

    Energy Technology Data Exchange (ETDEWEB)

    Fredenhagen, Stefan, E-mail: stefan.fredenhagen@aei.mpg.de [Max-Planck-Institut für Gravitationsphysik, Albert-Einstein-Institut Am Mühlenberg 1, 14476 Golm (Germany); Hoppe, Jens, E-mail: hoppe@kth.se; Hynek, Mariusz, E-mail: mkhynek@kth.se [Department of Mathematics, Royal Institute of Technology, KTH 100 44 Stockholm (Sweden)

    2015-10-15

    The emergence of a critical dimension is one of the most striking features of string theory. One way to obtain it is by demanding closure of the Lorentz algebra in the light-cone gauge quantisation, as discovered for bosonic strings more than forty years ago. We give a detailed derivation of this classical result based on the operator product expansion on the Lorentzian world-sheet.

  16. Lorentz Gauge Theory and Spinor Interaction

    CERN Document Server

    Carlevaro, Nakia; Montani, Giovanni

    2008-01-01

    A gauge theory of the Lorentz group, based on the different behavior of spinors and vectors under local transformations, is formulated in a flat space-time and the role of the torsion field within the generalization to curved space-time is briefly discussed. The spinor interaction with the new gauge field is then analyzed assuming the time gauge and stationary solutions, in the non-relativistic limit, are treated to generalize the Pauli equation.

  17. Lorentz Gauge Theory and Spinor Interaction

    Science.gov (United States)

    Carlevaro, Nakia; Lecian, Orchidea Maria; Montani, Giovanni

    A gauge theory of the Lorentz group, based on the different behavior of spinors and vectors under local transformations, is formulated in a flat space-time and the role of the torsion field within the generalization to curved space-time is briefly discussed. The spinor interaction with the new gauge field is then analyzed assuming the time gauge and stationary solutions, in the non-relativistic limit, are treated to generalize the Pauli equation.

  18. Radio Astronomical Polarimetry and the Lorentz Group

    OpenAIRE

    Britton, M. C.

    1999-01-01

    In radio astronomy the polarimetric properties of radiation are often modified during propagation and reception. Effects such as Faraday rotation, receiver cross-talk, and differential amplification act to change the state of polarized radiation. A general description of such transformations is useful for the investigation of these effects and for the interpretation and calibration of polarimetric observations. Such a description is provided by the Lorentz group, which is intimately related t...

  19. Neutrino velocity and local Lorentz invariance

    Science.gov (United States)

    Cardone, Fabio; Mignani, Roberto; Petrucci, Andrea

    2015-09-01

    We discuss the possible violation of local Lorentz invariance (LLI) arising from a faster-than-light neutrino speed. A toy calculation of the LLI violation parameter δ, based on the (disclaimed) OPERA data, suggests that the values of δ are determined by the interaction involved, and not by the energy range. This hypothesis is further corroborated by the analysis of the more recent results of the BOREXINO, LVD and ICARUS experiments.

  20. Unravelling Lorentz Covariance and the Spacetime Formalism

    Directory of Open Access Journals (Sweden)

    Cahill R. T.

    2008-10-01

    Full Text Available We report the discovery of an exact mapping from Galilean time and space coordinates to Minkowski spacetime coordinates, showing that Lorentz covariance and the space- time construct are consistent with the existence of a dynamical 3-space, and “absolute motion”. We illustrate this mapping first with the standard theory of sound, as vibra- tions of a medium, which itself may be undergoing fluid motion, and which is covari- ant under Galilean coordinate transformations. By introducing a different non-physical class of space and time coordinates it may be cast into a form that is covariant under “Lorentz transformations” wherein the speed of sound is now the “invariant speed”. If this latter formalism were taken as fundamental and complete we would be lead to the introduction of a pseudo-Riemannian “spacetime” description of sound, with a metric characterised by an “invariant speed of sound”. This analysis is an allegory for the development of 20th century physics, but where the Lorentz covariant Maxwell equa- tions were constructed first, and the Galilean form was later constructed by Hertz, but ignored. It is shown that the Lorentz covariance of the Maxwell equations only occurs because of the use of non-physical space and time coordinates. The use of this class of coordinates has confounded 20th century physics, and resulted in the existence of a “flowing” dynamical 3-space being overlooked. The discovery of the dynamics of this 3-space has lead to the derivation of an extended gravity theory as a quantum effect, and confirmed by numerous experiments and observations

  1. Lorentz transformations in terms of quaternions

    International Nuclear Information System (INIS)

    Transformations differ from Lorentz ones by absence of y'=y; z'=z requirements in case of Vx=V; Vy=Vz=0 are suggested. General transformations for optional V-vector are obtained. The given approach natural language is that of hypercomplex numbers. Some consequences of similar transformations in special relativity theory are discussed. Their relation to helical calculus, to polarization and spin properties of moving with relativistic velocities objects is underlined. These transformations matrix formulation is presented

  2. Lorentz-invariant non-commutative QED

    International Nuclear Information System (INIS)

    Lorentz-invariant non-commutative QED (NCQED) is constructed so as to be a part of the Lorentz-invariant non-commutative Standard Model (NCSM), a subject to be treated in later publications. Our NCSM is based on Connes' observation that the total fermion field in the Standard Model can be regarded as a bi-module over a flavor-color algebra. In this paper, it is shown that there exist two massless gauge fields in NCQED that are interchanged by the C' transformation. Since C' is reduced to the conventional charge conjugation C in the commutative limit, in the same limit, the two gauge fields become identical to the photon field which couples to only four spinors, with charges ±2, ±1. Following Carlson, Carone and Zobin, our NCQED respects Lorentz invariance, employing the Doplicher-Fredenhagen-Roberts algebra instead of the usual algebra with constant θμν. In the new version, θμν becomes an integration variable. We show, using a simple NC scalar model, that the θ integration yields an invariant damping factor instead of the oscillating one in the nonplanar self-energy diagram in the one-loop approximation. The Seiberg-Witten map shows that the θ expansion of NCQED generates exotic but well-motivated derivative interactions beyond QED, with allowed charges being only 0, ±1, ±2. (author)

  3. Gravity, Lorentz Violation, and the Standard Model

    CERN Document Server

    Kostelecky, V A

    2003-01-01

    The role of the gravitational sector in the Lorentz- and CPT-violating Standard-Model Extension (SME) is studied. A framework is developed for addressing this topic in the context of Riemann-Cartan spacetimes, which include as limiting cases the usual Riemann and Minkowski geometries. The methodology is first illustrated in the context of the QED extension in a Riemann-Cartan background. The full SME in this background is then considered, and the leading-order terms in the SME action involving operators of mass dimension three and four are constructed. The incorporation of arbitrary Lorentz and CPT violation into general relativity and other theories of gravity based on Riemann-Cartan geometries is discussed. The dominant terms in the effective low-energy action for the gravitational sector are provided, thereby completing the formulation of the leading-order terms in the SME with gravity. Explicit Lorentz symmetry breaking is found to be incompatible with generic Riemann-Cartan geometries, but spontaneous Lo...

  4. Commentary: Air-conditioning as a risk for increased use of healthservices

    Energy Technology Data Exchange (ETDEWEB)

    Mendell, Mark J.

    2004-06-01

    In this issue of the journal, Preziosi et al. [2004] report the first study to assess differences in the utilization of health care related to the presence of air-conditioning in office workplaces. Although the study was simple and cross-sectional, the data variables from questionnaires, and the findings subject to a variety of questions, the findings are striking enough to deserve clarification. The study used a large random national sample of French women assembled for another purpose (to study antioxidant nutrients and prevention of cancer and cardiovascular disease). Participants reported health services and health events in monthly questionnaires over 1 year, and in one questionnaire in the middle of that period also reported whether air-conditioning was in use at their workplace. Fifteen percent of participants reported air-conditioning at work. Analyses adjusting for age and smoking status of participants found increases in most outcomes assessed: use of specific kinds of physicians, sickness absence, and hospital stays. While the increases in odds ratios (OR) and 95% confidence intervals (CI) were statistically significant for only otorhinolaryngology [OR (95% CI) = 2.33 (1.35-4.04)] and sickness absence [1.70 (1.13-2.58)], other increases were notable--dermatology [1.6 (0.98-2.65)]; hospital stay [1.51 (0.92-2.45)], and pneumonology [2.10 (0.65-6.82)]. The least elevated outcomes were for general practice medicine [0.99 (0.65-1.48)] and global medical visits [1.18 (0.67-2.07)]. [Preziosi et al., 2004 ,(Table 2)] Odds ratios for relatively common health outcomes often lie farther from the null than the risk ratios most useful for quantifying the increase in risk. Risk ratios, or prevalence ratios (PRs, the equivalent measure of effect for cross-sectional data), have seldom been used because of the convenience and availability of logistic regression models that estimate odds ratios. With baseline prevalences ranging up to 85.7% in the data from Preziosi et

  5. Performance of R-410A Alternative Refrigerants in a Reciprocating Compressor Designed for Air Conditioning Applications

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, Som S [ORNL; Vineyard, Edward Allan [ORNL; Mumpower, Kevin [Bristol Compressors International, Inc.

    2016-01-01

    In response to environmental concerns raised by the use of refrigerants with high Global Warming Potential (GWP), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has launched an industry-wide cooperative research program, referred to as the Low-GWP Alternative Refrigerants Evaluation Program (AREP), to identify and evaluate promising alternative refrigerants for major product categories. After successfully completing the first phase of the program in December 2013, AHRI launched a second phase of the Low-GWP AREP in 2014 to continue research in areas that were not previously addressed, including refrigerants in high ambient conditions, refrigerants in applications not tested in the first phase, and new refrigerants identified since testing for the program began. Although the Ozone Depletion Potential of R-410A is zero, this refrigerant is under scrutiny due to its high GWP. Several candidate alternative refrigerants have already demonstrated low global warming potential. Performance of these low-GWP alternative refrigerants is being evaluated for Air conditioning and heat pump applications to ensure acceptable system capacity and efficiency. This paper reports the results of a series of compressor calorimeter tests conducted for the second phase of the AREP to evaluate the performance of R-410A alternative refrigerants in a reciprocating compressor designed for air conditioning systems. It compares performance of alternative refrigerants ARM-71A, L41-1, DR-5A, D2Y-60, and R-32 to that of R-410A over a wide range of operating conditions. The tests showed that, in general, cooling capacities were slightly lower (except for the R-32), but energy efficiency ratios (EER) of the alternative refrigerants were comparable to that of R-410A.

  6. Home air-conditioning, traffic exposure, and asthma and allergic symptoms among preschool children.

    Science.gov (United States)

    Zuraimi, Mohamed Sultan; Tham, Kwok-Wai; Chew, Fook-Tim; Ooi, Peng-Lim; Koh, David

    2011-02-01

    Epidemiological data suggest that traffic exposures can influence asthma and allergic symptoms among preschool children; however, there is no information on risk reduction via home air-conditioning (AC). The aim of this study is to evaluate the associations of self-reported traffic densities with asthma and allergic symptoms among preschool children and determine whether AC is an effect modifier. A cross-sectional study adopting an expanded and modified ISAAC--International Study of Asthma and Allergies in Childhood conducted on randomly selected 2994 children living in homes without any indoor risk factors. Specific information on demographics, indoor home risk factors, and traffic variables were obtained. Adjusted prevalence ratios (PR) and 95% confidence interval (CI) were determined by Cox proportional hazard regression model with assumption of a constant risk period controlled for covariates. We found dose-response significant relationships between validated self-reported traffic densities and asthma and rhinitis symptoms. Among children sleeping in non-air-conditioned homes, there were stronger associations between asthma and rhinitis symptoms studied. PRs for heavy traffic density were 2.06 for wheeze (95% CI 0.97-4.38), 2.89 for asthma (1.14-7.32), 1.73 for rhinitis (1.00-2.99), and 3.39 for rhinoconjunctivitis (1.24-9.27). There were no associations found for children sleeping in air-conditioned homes. Our results suggest that AC in the bedroom modifies the health effects of traffic among preschool children. This finding suggests that attention should also be paid to ventilation characteristics of the homes to remediate health-related traffic pollution problems. PMID:20561230

  7. Design guides for solar assisted air conditioning; Auslegungshinweise fuer die Solargestuetzte Klimatisierung

    Energy Technology Data Exchange (ETDEWEB)

    Franzke, U.; Seifert, C. [Institut fuer Luft- und Kaeltetechnik gGmbH, Dresden (Germany)

    2005-10-01

    The design of solar assisted air conditioning systems required a detailed consideration of the whole system, which consist of the building, the use, the air handling unit and the solar energy production. The decision about the application of solar energy is necessary in an earlier phase of the design process of the building. But at this moment, the necessary information are not available. With help of the simulation tool SOLAC it's possible to define an optimised system on a low level of information input. (orig.)

  8. Multi-variable Extremum Seeking Control for Mini-split Air-conditioning System

    OpenAIRE

    Xiao, Yan; Li, Yaoyu; Seem, John E.

    2014-01-01

    In this study, a multi-variable extremum seeking control (ESC) scheme is proposed for a variable-speed mini-split air-conditioning system. The control inputs are the evaporator and condenser fan speeds, respectively, while the total power consumption is used as the feedback. As accurate model is hard and expensive to obtain for the AC system of interest in real time, nearly model-free self-optimizing control methods such as ESC is considered a more feasible solution to practical deployment. R...

  9. Heat pump air conditioning system for pure electric vehicle at ultra-low temperature

    Directory of Open Access Journals (Sweden)

    Li Hai-Jun

    2014-01-01

    Full Text Available When the ordinary heat pump air conditioning system of a pure electric vehicle runs at ultra-low temperature, the discharge temperature of compressor will be too high and the heating capacity of the system will decay seriously, it will lead to inactivity of the heating system. In order to solve this problem, a modification is put forward, and an experiment is also designed. The experimental results show that in the same conditions, this new heating system increases more than 20% of the heating capacity; when the outside environment temperature is negative 20 degrees, the discharge temperature of compressor is below 60 degrees.

  10. Energy saving measures for automotive air conditioning (AC) system in the tropics

    OpenAIRE

    Subiantoro, Alison; Ooi, Kim Tiow; Stimming, Ulrich

    2014-01-01

    Air conditioning (AC) is an integral component of modern cars in the tropics. However, AC usage in this region consumes a large amount of energy. In conventional internal combustion engine cars, it consumes up to 30% of the fuel, while in battery electric cars, AC may reduce the battery range by up to 40%. Fortunately, there are various ways to improve the efficiency of automotive ACs in the tropics. In this paper, three energy saving measures are discussed. These include a higher indoor temp...

  11. Proposed energy-efficient air-conditioning system using liquid desiccant

    Energy Technology Data Exchange (ETDEWEB)

    Kinsara, Adnan A.; Al-Rabghi, Omar M. [King Abdulaziz Univ., Thermal Engineering Dept., Jeddah (Saudi Arabia); Elsayed, Moustafa M. [Kuwait Univ., Mechanical Engineering Dept., Safat (Kuwait)

    1996-10-01

    In this work, an energy-efficient system is proposed to reduce energy consumption in air-conditioning (A/C) systems using CaCl{sub 2} solution as a liquid desiccant. The proposed system consists mainly of two packed beds, a heat pump, air washers and a cooling coil. Mathematical modeling of various components and fluid properties of the proposed system was undertaken. A computer program was prepared to study the system performance under different conditions. The proposed system was found to be more energy-efficient than a conventional A/C system. (author)

  12. Simulation and analysis of a novel liquid desiccant air-conditioning system

    International Nuclear Information System (INIS)

    In this work a novel energy efficient air-conditioning system utilizing lithium chloride (LiCl) solution as liquid desiccant has been proposed and simulated. The simulation of this system is mainly formulated with two packed columns, one for regenerating the weak desiccant and the other for the dehumidification of ambient air. The air is first dehumidified in the dehumidifier and then sensibly cooled in the indirect and direct evaporative coolers. First and second laws of thermodynamics have been used to analyze the effect of five key variables on the performance of the system. High efficiency could be achieved if proper values of these variables are selected.

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

    Science.gov (United States)

    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. PMID:27055570

  14. Computerized Simulation of Automotive Air-Conditioning System: A Parametric Study

    OpenAIRE

    Haslinda Mohamed Kamar; Nazri Kamsah; Mohd Yusoff Senawi

    2013-01-01

    This paper presents results of a parametric study performed on an automotive air-conditioning (AAC) system of a passenger car. The goals are to assess the effects of varying the volumetric flow rate of supply air, number of occupants, vehicle speed, and the fractional ventilation air intake (XOA), on the dry-bulb temperature and specific humidity of the air inside the passengers cabin, and on the evaporator coil cooling load of the AAC system. Results of the parametric study show that increas...

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

    Science.gov (United States)

    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.

  16. Investigation on the Energy Consumption of a Communications Room Using Fresh Air and Air Condition System%新风和空调系统应用于通信机房的能耗研究

    Institute of Scientific and Technical Information of China (English)

    范轩; 曹小林; 黄晓峰; 谭诒煌

    2015-01-01

    以通信机房的空调能耗为研究对象,利用 TRNSYS 模拟软件建立未利用/利用新风系统时的通信机房的空调能耗模型。模拟研究通信机房的空调负荷、围护结构传热量等数据,将2种模型进行对比,并分析围护结构对空调负荷及围护结构传热量的影响趋势及变化规律。%The energy consumption of communication equipment room is the main study object,establishing the air conditioning energy consumption model of the communication equipment room when not using/using the new air system utilizing TRNSYS sim-ulation software.Numerical simulations were used to investigate the air conditioning load and the wall gain load of communication equipment room,the two models are compared,and analyse impact trend and change rule of meteorological parameters and build-ing envelope to air conditioning load and heat transmission capacity of building envelope.

  17. Acoustics of motor car air conditioning systems; Akustik der Kfz-Klimaanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Matthes, M.; Martini, J.; Cucuz, S. [Visteon Deutschland GmbH, VTZ Kerpen (Germany)

    2002-07-01

    Air conditioning systems in motor cars provide thermal comfort but the noise level may increase to an extent that makes the driver shut off the air conditioning system altogether. The contribution presents an introduction to acoustics. The human ear is described, and typical acoustic parameters like sound pressure, sound intensity, acoustic power and level definitions are introduced. Measuring systems and techniques are described, and typical problems and solutions in air conditioner acoustics are gone into. Finally, empirical estimates are made for the sound pressure level of ventilation nozzles and air conditioners. [German] Gestiegene Komfortansprueche der Kfz-Insassen haben in Europa waehrend der letzten Dekade die Kfz-Klimaanlage zu einem Standard-Ausstattungsmerkmal in der oberen Mittelklasse werden lassen, und auch kleinere Fahrzeugklassen (B- und C-Segment) folgen dieser Entwicklung auf dem Fusse. Die Hauptaufgabe der Kfz-Klimaanlage - die Bereitstellung des thermischen Komforts - wird aber mit akustischen Belastungen der Fahrzeuginsassen erkauft. Die akustische Belastung kann dabei so gross werden, dass die Insassen von einem optimalen Gebrauch der Klimaanlage absehen - einfach weil sie zu laut ist. Um einen moeglichst umfassenden Einblick in die Akustik zu gewaehren, wird zunaechst das menschliche Gehoer vorgestellt. Danach werden typische Kenngroessen der Akustik wie Schalldruck, Schallintensitaet und Schallleistung und die entsprechenden Pegeldefinitionen eingefuehrt. Im zweiten Abschnitt werden Messraeume und Messverfahren vorgestellt, um dann auf typische Probleme und Loesungsmoeglichkeiten in der Klimageraeteakustik einzugehen. Schliesslich werden empirische Abschaetzungen fuer den Schalldruckpegel von Belueftungsduesen und Klimageraeten vorgestellt. (orig.)

  18. Vibro-acoustic characterization of flexible hose in CO2 car air conditioning systems

    Science.gov (United States)

    Angelini, F.; Bergami, A.; Martarelli, M.; Tomasini, E. P.

    2008-06-01

    Following the EU directive 2006/40/EC proscribing from 2011 that refrigerant fluids must have a global warming potential not higher than 150, it will not be allowed anymore to employ the current R134a on car air conditioning systems. Maflow s.p.a (automotive hose maker) is developing products for each possible new refrigerant. This paper is focused on hoses for CO2 refrigerants operating in the worst conditions because of the high pressures and temperatures at which they are working (with R134a the high pressure is 18 bar and low pressure is 3 bar; with CO2 the high pressure is 100 bar and low pressure is 35 bar). Therefore the noise emission control of the CO2 air conditioning systems is very important. The aim of this study is to develop a standard measurement method for the vibro - acoustic characterization of High Pressure (HP - Shark F4) and Low Pressure (LP - ULEV) hoses to reduce noise emission and raise car passenger comfort; in particular deep research on high pressure hose. The method is based on the measurement of the vibration level of the hoses in a standard test bench by means of a Laser Doppler Vibrometer (LDV) and its acoustic emission by a sound intensity probe.

  19. Gas Engine-Driven Heat Pump Chiller for Air-Conditioning and Hot Water Supply Systems

    Science.gov (United States)

    Fujita, Toshihiko; Mita, Nobuhiro; Moriyama, Tadashi; Hoshino, Norimasa; Kimura, Yoshihisa

    In Part 1 of this study, the performance characteristics of a 457kW gas engine-driven heat pump (GHP) chiller have been obtained from a simulation model analysis for both cooling and heating modes and it has been found that the part-load characteristics of the GHP chiller are fairly well. On the back of Part 1, a computer simulation program has been developed for the evaluation of GHP chiller systems to compare with the other types of heat source systems for air-conditioning and hot water supply applications. The simulation program can be used to estimate annual energy consumption, annual CO2 emission, etc. of the systems with the data of monthly and hourly thermal loads on various buildings, outdoor air conditions, and characteristics of various components comprising the systems. By applying this to some cases of medium-scale hotel, office, shop, and hospital buildings, it has been found that the GHP chiller systems have advantages particularly in the cases of hotels and hospitals where a lot of hot water demand exists. It has also been found that the combination of a GHP chiller and a direct-fired absorption water chiller boiler (hot and chilled water generator) appears promising.

  20. Research on phase-change material building mass applied in the air-conditioning field

    Institute of Scientific and Technical Information of China (English)

    YANQuanying

    2003-01-01

    Phase-change material building mass contains phase-change matenals. It can decrease air-conditioning load and indoor temperature fluctuations, and improve comfort degree in summer because of thermal storage property of phase-change material. Thereby, the scale, initial investment and operational cost of air-conditioning system decrease effectively. The indoor surroundings improve. In this paper, suitable phase-change material used in architecture and combination mode between phase change material and architectural material were studied. By considering the properties of materials, such as phase-change temperature, phase-change latent heat, thermal conductivity and expansion coefficient, phase-change materials were selected and evaluated. Combination mode between phase-change material and architectural material were provided. The influence of phase-change material structure on thermal performance in room and energy-saving effect were analyzed and compared with traditional structure without phase-change material. It is proved that phase-change material structure is feasible in the practical engineenng. These provide the basis for developing phase-change material building mass.

  1. Genetic Optimization Algorithm of PID Decoupling Control for VAV Air-Conditioning System

    Institute of Scientific and Technical Information of China (English)

    WANG Jiangjiang; AN Dawei; ZHANG Chunfa; JING Youyin

    2009-01-01

    Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multi-variable decoupling PID controller is designed for VAV air-conditioning system. Diagonal matrix decoupling method is employed to eliminate the coupling between the loop of supply air temperature and that of thermal-space air temperature. The PID controller parameters are optimized by means of an improved genetic algorithm in floating point representations to obtain better performance. The population in the improved genetic algorithm mutates before crossover, which is helpful for the convergence. Additionally the micro mutation algorithm is proposed and applied to improve the convergence during the later evolution. To search the best parameters, the optimized parameters ranges should be amplified l0 times the initial ideal parameters. The simulation and experiment results show that the decoupling control system is effective and feasible. The method can overcome the strong coupling feature of the system and has shorter governing time and less over-shoot than non-optimization PID control.

  2. Experimental Study of Air Conditioning Unit of Evaporative Cooling Assisted Mechanical Refrigeration

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiang; XU Fang-cheng; WU Jun-mei

    2009-01-01

    The evaporative cooling,which assists the refrigeration machinery air-conditioning systems test-rig,has been designed.Its structure and working principle were described,and the performance test was con-ducted and analyzed.The test shows that making full use of the evaporative cooling"free cooling" in Spring and Autumn seasons can fully meet the requirements of air-conditioned comfort through the switch of the function in different seasons.Taking into account the evaporative cooling fan and pump energy consumption,compared with the traditional mechanical refrigeration system,more than 80 percent of energy can be saved,and the ener-gY efficiency ratio of the Unit(EER) is as high as 7.63.Using the two stages of indirect evaporative cooling to pre-cool the new wind in summer,under the conditions of the same air supply temperature requirements,0.83 kg/s chilled water saved can be equivalent to the traditional mechanical refrigeration system,and when the newwind ratio up to 50 percent.more than 10 percent load was reduced in mechanical refrigeration system.The overall EER increased about 35 percent.

  3. The Impact of Air Exchange Effectiveness on Thermal Comfort in an Air-Conditioned Office

    Directory of Open Access Journals (Sweden)

    Roonak Daghigh

    2009-01-01

    Full Text Available Problem statement: Impact of air exchange effectiveness on thermal comfort has not been investigated and, therefore, not well understood .Therefore, the influence of air exchange effectiveness on thermal comfort is investigated in this study. Approach: The main objective of this research is to investigate the thermal comfort level of an air-conditioned office room under 14 windows-door opening arrangements as a function of maximum, minimum and mean Air Exchange Effectiveness (AEE, as has not been inquired into already. The tracer gas decay method has been applied during the experimental procedures to estimate air exchange effectiveness, on the basis of room average and local mean age of air. Simultaneously, thermal comfort variables were measured and through these data, the thermal comforts Fanger's indices (PMV and PPD were calculated. Staff answered a survey on their sensation of the indoor climate. Results: Results of 60 survey responses to thermal comfort questions in office and indoor air quality are presented. This study has shown that there are relationship between AEE and thermal comfort and three linear regression equations of PMV versus AEE can be derived for this air-conditioned office. Conclusion: Studies on the effect of air exchange effectiveness on thermal comfort in an office have shown that Thermal comfort is influenced by AEE, which go beyond the six factors which have been taken into account in PMV modeling.

  4. Cleaning and air conditioning device for atmosphere in thermonuclear reactor chamber

    International Nuclear Information System (INIS)

    The device of the present invention removes tritium efficiently and attains ventilation and conditioning of a great amount of air flow. That is, there are disposed a humidity separator, a filter, a heater, a catalyst filled layer, a water jetting type humidifying heat insulation cooler and a cooler in this order from an inlet side (upstream) of contaminated room atmospheric gases. The catalyst filled layer, etc. are incorporated integrally into the ventilation air conditioning facility for ventilating air in the chamber of the thermonuclear reactor, to clean a tritium atmosphere at the same time. Accordingly, the device is made compact as a whole. A limit for the air flow rate owing to the use of the conventional catalyst tower and adsorbing tower is eliminated. Then a ventilating air conditioning for a great flow rate can be attained. Tritium is removed by cooling and dehumidification without using any adsorbent. Accordingly, an adsorbing tower is no more necessary and conventional regeneration operation is not required. As a result, space for installation is reduced, the system is simplified and the cost for construction and facility can be reduced. (I.S.)

  5. Impact of summer office set air-conditioning temperature on energy consumption and thermal comfort

    Institute of Scientific and Technical Information of China (English)

    刘红; 马小磊; 高亚峰

    2009-01-01

    To explore the relationship between summer office set air-conditioning temperature and energy consumption related to air conditioning use to provide human thermal comfort,a comparison experiment was conducted in three similar offices at temperatures of 24,26 and 28 ℃ respectively. A thermal comfort questionnaire survey was conducted. It is demonstrated that air-conditioner energy consumption at the set temperature of 28 ℃ is 113% and 271% lower than at 26 ℃ and 24 ℃,respectively. A linear relationship exists between air-conditioner energy consumption and the indoor and outdoor temperature difference. When comfortably dressed,over 80% of research participants accept the set temperature of 28 ℃. The regression analysis leads to a neutral temperature of 26.2 ℃ and an acceptable temperature of 28.2 ℃ for over 80% of the research participants subjects,indicating that the current 26 ℃ set temperature for offices in summer,required by Chinese General Office of the State Council,can be increased to 28 ℃. Moreover,analysis of predicted mean vote(PMV) index shows that a set temperature of 27 ℃,not 26 ℃,is sufficiently comfortable for office staff wearing long-sleeve shirts,long pants and leather shoes.

  6. Refrigerant Control Strategies for Residential Air-Conditioning and Heat-Pump System

    Institute of Scientific and Technical Information of China (English)

    SU Shun-yu; ZHANG Chun-zhi; CHEN Jian

    2009-01-01

    This paper simulated the optimal refrigerant charge inventory of a refrigeration system in air-con-ditioning operation and heat-pump operation respectively,and studied the refrigerant control strategies in this system.The void fraction in two-phase fluid region was calculated by Harms model.And based on distributed parameter model and Harms model,the refrigerant charge inventory in condenser and evaporator were calculated and analyzed in air-conditioning conditions and heat-pump conditions,respectively.The calculating results of dif-ferent refrigerant mass between refrigeration and heating conditions indicate that the optimal refrigerant charge inventory in heat-pump conditions is lower than that in air-eonditioning conditions.To avoid the decrease of COP due to the surplus refrigerant in heating conditions,we introduced the liquid reservoir control method and associate capillary control method.Both of them could increase the heating capacity of the air-source heat pump-The difference of optimal refrigerant charge inventory in air-conditioning and heat-pump system can be controlled by the liquid reservoir or the associate capillary.

  7. Ventilation and air conditioning facility turbine building in nuclear power plant

    International Nuclear Information System (INIS)

    In the facility of the present invention, the exhaustion capacity of an exhaustion blower, an exhaustion duct or a main exhaustion stack are decreased to reduce cost for buildings and running cost. That is, the facility of the present invention has an exhaustion port at a position higher than an air supply port disposed to the outer wall of an operation floor of a turbine building. During usual operation, ventilation and air conditioning are conducted for the operation floor by natural circulating ventilation in which air is supplied from the air supply port and exhausted from the exhaustion port. Upon periodical inspection, ventilation and air conditioning are conducted for the operation floor by supplying air from the air supply port and exhausting it from the main exhaustion stack. When air is exhausted from the main exhaustion stack, a means for disposing an exhaustion system exclusively used for the operation floor having a separately disposed exhaustion blower connected to the main exhaustion stack is used or a means capable of selectively communicating the operation floor with a contamination area exhaustion system in the turbine building is used. With such a constitution, the capacity of the exhaustion system is reduced during both of the usual operation and periodical inspection. Further, upon periodical inspections, if air is exhausted from the main exhaustion stack by way of the exhaustion system exclusively used for the turbine building operation floor, the balance for the total amount of airflow is not lost. (I.S.)

  8. Overview of the SME: Implications and Phenomenology of Lorentz Violation

    CERN Document Server

    Bluhm, R

    2005-01-01

    The Standard Model Extension (SME) provides the most general observer-independent field theoretical framework for investigations of Lorentz violation. The SME lagrangian by definition contains all Lorentz-violating interaction terms that can be written as observer scalars and that involve particle fields in the Standard Model and gravitational fields in a generalized theory of gravity. This includes all possible terms that could arise from a process of spontaneous Lorentz violation in the context of a more fundamental theory, as well as terms that explicitly break Lorentz symmetry. An overview of the SME is presented, including its motivations and construction. Some of the theoretical issues arising in the case of spontaneous Lorentz violation are discussed, including the question of what happens to the Nambu-Goldstone modes when Lorentz symmetry is spontaneously violated and whether a Higgs mechanism can occur. A minimal version of the SME in flat Minkowski spacetime that maintains gauge invariance and power...

  9. Are the invariance principles really truly Lorentz covariant?

    International Nuclear Information System (INIS)

    It is shown that some sections of the invariance (or symmetry) principles such as the space reversal symmetry (or parity P) and time reversal symmetry T (of elementary particle and condensed matter physics, etc.) are not really truly Lorentz covariant. Indeed, I find that the Dirac-Wigner sense of Lorentz invariance is not in full compliance with the Einstein-Minkowski reguirements of the Lorentz covariance of all physical laws (i.e., the world space Mach principle)

  10. Neutrino Oscillations, Lorentz/CPT Violation, and Dark Energy

    CERN Document Server

    Ando, Shin'ichiro; Mocioiu, Irina

    2009-01-01

    If dark energy (DE) couples to neutrinos, then there may be apparent violations of Lorentz/CPT invariance in neutrino oscillations. The DE-induced Lorentz/CPT violation takes a specific form that introduces neutrino oscillations that are energy independent, differ for particles and antiparticles, and can lead to novel effects for neutrinos propagating through matter. We show that ultra-high-energy neutrinos may provide one avenue to seek this type of Lorentz/CPT violation in \

  11. Lorentz-violating effects in three-dimensional $QED$

    OpenAIRE

    Bufalo, R.

    2014-01-01

    Inspired in discussions presented lately regarding Lorentz-violating interaction terms in \\cite{13,6}, we propose here a slightly different version for the coupling term. We will consider a modified quantum electrodynamics with violation of Lorentz symmetry defined in a $\\left( 2+1\\right) $-dimensional spacetime. We define the Lagrangian density with a Lorentz-violating interaction, where the the spacetime dimensionality is explicitly taken into account in its definition. The work encompasses...

  12. Lorentz symmetry breaking effects on relativistic EPR correlations

    Energy Technology Data Exchange (ETDEWEB)

    Belich, H. [Universidade Federal do Espirito Santo, Departamento de Fisica e Quimica, Vitoria, ES (Brazil); Furtado, C.; Bakke, K. [Universidade Federal da Paraiba, Departamento de Fisica, Caixa Postal 5008, Joao Pessoa, PB (Brazil)

    2015-09-15

    Lorentz symmetry breaking effects on relativistic EPR (Einstein-Podolsky-Rosen) correlations are discussed. From the modified Maxwell theory coupled to gravity, we establish a possible scenario of the Lorentz symmetry violation and write an effective metric for the Minkowski spacetime. Then we obtain the Wigner rotation angle via the Fermi-Walker transport of spinors and consider the WKB (Wentzel-Kramers-Brillouin) approximation in order to study the influence of Lorentz symmetry breaking effects on the relativistic EPR correlations. (orig.)

  13. Air conditioning on turbo-generator input using waste heat of pyrolysis technology of solid domestic waste utilization

    OpenAIRE

    Ryzhkov, Serhiy S.; Markina, Liudmyla M.; Serbin, Serhii I.; Radchenko, Mykola I.

    2014-01-01

    The efficiency is studied of using waste heat of condensation of utilization technology of solid domestic waste by means of pyrolysis for air conditioning (cooling with drying) on the input of the turbo-generator which works at pyrolysis gas.

  14. The Histoty of Ventilation and Air Conditioning is CERN Up to Date with the latest Technological Developments?

    CERN Document Server

    Kühnl-Kinel, J

    2000-01-01

    The invention of ventilation cannot be ascribed to a certain date. It started with simple aeration when man brought fire into his abode and continued through different stages including air cooling using ice to finally arrive at the time when ventilation and air conditioning has become an essential part of our life and plays an important role in human evolution. This paper presents the history of ventilation and air conditioning, explains the key constraints over the centuries, and shows its influence on everyday life. Some examples of previous air-conditioning plants are described and different approaches to the way of calculation of ventilation systems discussed. It gives an overview of the Heating, Ventilation and Air Conditioning (HVAC) installations at CERN and points out their particularities. It also compares them with the latest technological developments in the field as well as showing the new trends that are being applied at CERN.

  15. 48 CFR 22.1003-6 - Repair distinguished from remanufacturing of equipment.

    Science.gov (United States)

    2010-10-01

    ... contract principally for this type of work is subject to the Service Contract Act. Examples of such work..., tractor, crane, aerospace, air conditioning and refrigeration equipment, electric motors, and...

  16. New clock comparison searches for Lorentz and CPT violation

    International Nuclear Information System (INIS)

    We present two new measurements constraining Lorentz and CPT violation using the 129Xe/3He Zeeman maser and atomic hydrogen masers. Experimental investigations of Lorentz and CPT symmetry provide important tests of the framework of the standard model of particle physics and theories of gravity. The two-species 129Xe/3He Zeeman maser bounds violations of CPT and Lorentz symmetry of the neutron at the 10-31 GeV level. Measurements with atomic hydrogen masers provide a clean limit of CPT and Lorentz symmetry violation of the proton at the 10-27 GeV level

  17. Lorentz-violating spinor electrodynamics and Penning traps

    CERN Document Server

    Ding, Yunhua

    2016-01-01

    The prospects are explored for testing Lorentz- and CPT-violating quantum electrodynamics in experiments with Penning traps. We present the Lagrange density of Lorentz-violating spinor electrodynamics with operators of mass dimensions up to six, and we discuss some of its properties. The theory is used to derive Lorentz- and CPT-violating perturbative shifts of the energy levels of a particle confined to a Penning trap. Observable signals are discussed for trapped electrons, positrons, protons, and antiprotons. Existing experimental measurements on anomaly frequencies are used to extract new or improved bounds on numerous coefficients for Lorentz and CPT violation, using sidereal variations of observables and comparisons between particles and antiparticles.

  18. Low Energy Lorentz Violation from Modified Dispersion at High Energies.

    Science.gov (United States)

    Husain, Viqar; Louko, Jorma

    2016-02-12

    Many quantum theories of gravity propose Lorentz-violating dispersion relations of the form ω=|k|f(|k|/M⋆), with recovery of approximate Lorentz invariance at energy scales much below M⋆. We show that a quantum field with this dispersion predicts drastic low energy Lorentz violation in atoms modeled as Unruh-DeWitt detectors, for any f that dips below unity somewhere. As an example, we show that polymer quantization motivated by loop quantum gravity predicts such Lorentz violation below current ion collider rapidities. PMID:26918976

  19. Present Situation and Development Trend of Mine Air Conditioning in China%我国矿井空调的现状及发展趋势

    Institute of Scientific and Technical Information of China (English)

    张习军

    2014-01-01

    阐述了我国矿井空调的发展历程,并通过对我国热害矿井数据的整理分析,指出了我国热害矿井的基本特征。以132对热害矿井为样本,总结出我国热害矿井的区域性分布特征,并抽取其中的61对安装了制冷设备的矿井,从最大开采深度、地温类型和致热因素3个方面分析了热害矿井的基本特征。在此基础上,进一步介绍了我国矿井空调的分类,并统计了我国矿井空调的发展规模及其分布情况。结合目前的现状,对我国矿井空调的发展方向进行了展望。%This paper expounded the developing course of mine air conditioning in our country, and pointed out the basic characteristics of the mines with thermal pollution through the analysis of the thermal pollution data of such mines. By taking 132 thermal pollution mines as the sample, the paper summarized the regional distribution characteristic of the thermal pollution mines in our country, the basic features of the thermal pollution mines was analyzed from three aspects of the maximum mining depth, the geothermic type and thermal generation factors for 61 mines in which the refrigeration equipment was installed. On this basis, it further described the classification of mine air conditioning and summed up the development scale and distribution of mine air conditioning in our country. Finally, the prospect was made for the development direction of mine air conditioning in our country according to the present situation.

  20. Numerical simulation and performance assessment of an absorption solar air-conditioning system coupled with an office building

    OpenAIRE

    Thomas, Sébastien; Andre, Philippe

    2010-01-01

    To minimize environmental impact and CO2 production associated with air-conditioning, it is reasonable to evaluate the prospects of a clean energy source. Solar energy, via thermal collectors can provide a part of the heating needs. Moreover, it can drive absorption chiller in order to satisfy the cooling needs of buildings. The objective of the work is to evaluate accurately the energy consumption of an air conditioning system including a solar driven absorption chiller. The c...

  1. Air conditioning in the region of Madrid, Spain: an approach to electricity consumption, economics and CO₂emissions

    OpenAIRE

    Izquierdo, Marcelo; Moreno-Rodríguez, A.; González-Gil, A.; García-Hernando, Néstor

    2011-01-01

    An understanding of electricity consumption due to residential air conditioning (AC) may improve production and environmental impact strategy design. This article reports on a study of peak and seasonal electricity consumption for residential air conditioning in the region of Madrid, Spain. Consumption was assessed by simulating the operation of AC units at the outdoor summer temperature characteristics of central Spain. AC unit performance when operating under part load conditions in keep...

  2. Comparison and Evaluation of a New Innovative Drive Concept for the Air Conditioning Compressor of Electric Vehicles

    OpenAIRE

    Aurich, Joerg; Baumgart, Rico; Danzer, Christoph; Ackermann, Jan

    2014-01-01

    The development of an energy efficient air conditioning system for electric vehicles is an ever increasing challenge, because the cooling as well as the heating of the passenger cell reduces the cruising range dramatically. Almost always the compressor of the air conditioning system in electric cars is a scroll compressor with a separate electric motor and appropriate power electronics. However, this solution is critical in terms of the installation space, the weight and also the costs. There...

  3. An Investigation of Refrigerant Oil Retention in an Air Conditioning System with Two Inverter Compressors in Parallel

    OpenAIRE

    Kuo, Cheng-Shu; Cheng, Wei-Yueh; Hsieh, Wen-Der; Liu, Yangguang

    2012-01-01

    A VRF (variable refrigerant flow) air conditioning, having a number of air handling units connected to an external condensing unit, commonly uses two or more compressors in the system. The complicated piping system of the VRF air conditioning causes difficulties for refrigerant oils to return back to each compressor, especially for compressors operating in different frequencies. Compressors need lubrication in operation process, otherwise the compressor will burn out because of wearing and ov...

  4. COP Prediction of an ejector refrigeration cycle combined with a vapour compression cycle for automotive air conditioning

    OpenAIRE

    Nat Suvarnakuta; Nutthanun Keerlatiyadatanapat; Thanarath Sriveerakul

    2014-01-01

    This paper presents the COP prediction of an ejector refrigeration cycle combined with a vapour compression cycle for automotive air conditioning. Using computational fluid dynamics (CFD) technique, the performance of an ejector was analyzed in term of the entrainment ratio (Rm) and critical back pressure (CBP). The results from this study were compared with a previous study of combined ejector refrigeration system for automotive air conditioning application [1] which the entrainment ratio (R...

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

    Science.gov (United States)

    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. PMID:16739804

  6. Lorentz transformations as Lie-Poisson symmetries

    CERN Document Server

    Simoni, A; Yakushin, I; Simoni, A; Stern, A; Yakushin, I

    1995-01-01

    We write down the Poisson structure for a relativistic particle where the Lorentz group does not act canonically, but instead as a Poisson-Lie group. In so doing we obtain the classical limit of a particle moving on a noncommutative space possessing SL_q(2,C) invariance. We show that if the standard mass shell constraint is chosen for the Hamiltonian function, then the particle interacts with the space-time. We solve for the trajectory and find that it originates and terminates at singularities.

  7. Testing Lorentz invariance in β decay

    Directory of Open Access Journals (Sweden)

    Sytema A.

    2014-03-01

    Experimentally we exploit the Gamow-Teller transition of polarized 20Na, where we can test the dependence of the β-decay rate on the spin orientation of 20Na. The polarization degree is measured using the β asymmetry, while the decay rate is measured by the γ yield. A change in the γ rate, when reversing the spin, implies Lorentz invariance violation. The decay rate should depend on sidereal time and the polarization direction relative to the rotation axis of the earth. The method of the measurement will be presented, together with the first results.

  8. Neutrinos superluminality and Local Lorentz Invariance

    CERN Document Server

    Cardone, F; Petrucci, A

    2011-01-01

    The recent measurement of the neutrino velocity with the OPERA detector in the CNGS beam, on whose basis it was found that (v-c)/c = (2.48 \\pm 0.28 (stat.) \\pm 0.30 (sys.)) 10e-5, does not contain any significant violation of Local Lorentz Invariance (LLI), since the corresponding value of the parameter delta=(u/c)^2-1, that represents the upper limit of the breakdown of LLI, is at least three orders of magnitude higher than the known lower limit reported in literature and is compatible with the values estimated by other experiments carried out so far.

  9. Lorentz Nonreciprocal Model for Hybrid Magnetoplasmonics

    Science.gov (United States)

    Floess, Dominik; Weiss, Thomas; Tikhodeev, Sergei; Giessen, Harald

    2016-08-01

    Using localized surface plasmons, the magneto-optical response of dielectric thin films can be resonantly amplified and spectrally tailored. While the experimental realization and numerical simulation of such systems received considerable attention, so far, there is no analytical theoretical description. Here, we present a simple, intrinsically Lorentz nonreciprocal coupled oscillator model that reveals the underlying physics inside such systems and yields analytical expressions for the resonantly enhanced magneto-optical response. The predictions of the model are in good agreement with rigorous numerical solutions of Maxwell's equations for typical sample geometries. Our ansatz is transferable to other complex and hybrid nanooptical systems and will significantly facilitate device design.

  10. Mixed Lorentz boosted $Z^{0}'s$

    CERN Document Server

    Kjaer, N J

    2001-01-01

    A novel technique is proposed to study systematic errors on jet reconstruction in W physics measurements at LEP2 with high statistical precision. The method is based on the emulation of W pair events using Mixed Lorentz Boosted Z0 events. The scope and merits of the method and its statistical accuracy are discussed in the context of the DELPHI W mass measurement in the fully hadronic channel. The numbers presented are preliminary in the sense that they do not constitute the final DELPHI systematic errors.

  11. Experimental investigation on the photovoltaic-thermal solar heat pump air-conditioning system on water-heating mode

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Guiyin; Hu, Hainan; Liu, Xu [Department of Physics, Nanjing University, Nanjing 210093 (China)

    2010-09-15

    An experimental study on operation performance of photovoltaic-thermal solar heat pump air-conditioning system was conducted in this paper. The experimental system of photovoltaic-thermal solar heat pump air-conditioning system was set up. The performance parameters such as the evaporation pressure, the condensation pressure and the coefficient of performance (COP) of heat pump air-conditioning system, the water temperature and receiving heat capacity in water heater, the photovoltaic (PV) module temperature and the photovoltaic efficiency were investigated. The experimental results show that the mean photovoltaic efficiency of photovoltaic-thermal (PV/T) solar heat pump air-conditioning system reaches 10.4%, and can improve 23.8% in comparison with that of the conventional photovoltaic module, the mean COP of heat pump air-conditioning system may attain 2.88 and the water temperature in water heater can increase to 42 C. These results indicate that the photovoltaic-thermal solar heat pump air-conditioning system has better performances and can stably work. (author)

  12. Introduction Analysis of Refrigerating and Air-Conditioning Technologies in Micro Grid Type Food Industrial Park

    Science.gov (United States)

    Shimazaki, Yoichi

    The aim of this study was to evaluate the refrigerating and air-conditioning technologies in cases of introducing both cogeneration system and energy network in food industrial park. The energy data of 14 factories were classified into steam, hot water, heating, cooling, refrigerating, freezing and electric power by interviews. The author developed a micro grid model based on linear programming so as to minimize the total system costs. The industrial park was divided into the 2,500 square meter mesh in order to take steam transport into consideration. Four cases were investigated. It was found that the electric power driven freezer was introduced compared with the ammonia absorption freezer. The ammonia absorption freezer was introduced in the factory that there is a little steam demand and large freezing demand at the same time.

  13. Modeling solar-driven ejector refrigeration system offering air conditioning for office buildings

    Energy Technology Data Exchange (ETDEWEB)

    Guo, J.; Shen, H.G. [School of Environmental Science and Engineering, Donghua University, 2999 North Renmin Road, Shanghai 201620 (China)

    2009-02-15

    A lumped method combined with dynamic model is proposed for use in investigating the performance and solar fraction of a solar-driven ejector refrigeration system (SERS) using R134a, for office air conditioning application for buildings in Shanghai, China. Classical hourly outdoor temperature and solar radiation model were used to provide basic data for accurate analysis of the system performance. Results indicate that during the office working-time, i.e., from 9:00 to 17:00, the average COP and the average solar fraction of the system were 0.48 and 0.82 respectively when the operating conditions were: generator temperature (85 C), evaporator temperature (8 C) and condenser temperature varying with ambient temperature. Compared with traditional compressor based air conditioner, the system can save upto 80% electric energy when providing the same cooling capacity for office buildings. Hence, the system offers a good energy conservation method for office buildings. (author)

  14. Voltage controller design for air conditioning; Diseno de controlador de voltaje para aire acondicionado

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Andrade, R; Lopez Villalobos, J.J; Valderrama Chairez, J; Ramirez, R.L. [Instituto Tecnologico de Nuevo Leon, Guadalupe, Nuevo Leon (Mexico)]. E-mails: roxana_garciaandrade@yahoo.com; xe2n@yahoo.com.mx; jose.valderrama@ieee.org

    2013-03-15

    This paper discusses the design of a voltage controller for an air conditioning system in order to generate additional power in activation or startup of the system, for which as a first stage is presented the modeling power generation of electric current through alternative means, such as solar energy. The results of this study will be the basis for development of the physical prototype of this system controller. [Spanish] El presente trabajo trata sobre el diseno de un controlador de voltaje para un sistema de aire acondicionado con el fin de generar energia adicional en la activacion o arranque de dicho sistema, para lo cual como primer fase se presenta el modelado de la generacion de corriente electrica mediante medios alternos, como lo es la energia solar. Los resultados de este trabajo seran la base para desarrollo del prototipo fisico de este sistema controlador.

  15. Comparative study of air conditioning systems with vapor compression chillers using the concept of green buildings

    Directory of Open Access Journals (Sweden)

    Gutenberg da Silva Pereira

    2015-10-01

    Full Text Available This paper sets out to compare two different cooling systems that use vapor compression chillers for air conditioning environments. It was proposed to compare different operations in isolated and combined action operations. These operations are evaluated in the concepts of green buildings. A mathematical model was developed based on the principles of mass and energy conservation and complemented by various functions so as to determine the thermophysical properties and efficiencies of the compressors. The equations of the model were solved by the EES (Engineering Equation Solver program. The model evaluates the influence of the main HVAC operating parameters of the chilled water system when operating under three different configurations. The results showed that the system with a differentiated compression presents a COP equal to that of the system with screw chillers in the range  0-300 RTs, and a COP hat is on average 9% higher in the range 400-800 RTs.

  16. Aspects Related to the Control of the Secondary Flow of Water in Centralized Air Conditioning

    Directory of Open Access Journals (Sweden)

    Hechavarría-Hernández J.R.

    2012-07-01

    Full Text Available In this paper the tuning of the proportional integral controller, incorporated in the variable frequency drive implemented on the secondary variable flow system of cold water of the centralized air conditioning system of a Hotel is carried out. The proportional gain and the time of integration that guarantee a minimum error of one kPa in the control of pressure were defined. A focus multi-variable of the system is presented. It is defined the structure of artificial neural network that better it predicts the behaviour of the pressure, the power and return temperature with an adjustment of 94%. It is determined that there is a saving of 13% of electric power, in similar operation conditions, when using a control for closed loop with respect to a control for open loop.

  17. Parametric study of an energy efficient air conditioning system using liquid desiccant

    Energy Technology Data Exchange (ETDEWEB)

    Kinsara, Adnan A.; Al-Rabghi, Omar M. [King Abdulaziz Univ., Mechanical Engineering Dept., Jeddah (Saudi Arabia); Elsayed, Moustafa M. [Kuwait Univ., Mechanical Engineering Dept., Safat (Kuwait)

    1998-05-01

    Liquid desiccant can be used effectively to reduce energy consumed in air conditioning (AC). Unlike conventional AC, the latent part of the cooling load is overcome using liquid desiccant. In a previous article, an energy efficient system utilizing CaCl{sub 2} as liquid desiccant was proposed. This study is an extension of that work. The effect of key variables on the performance of the proposed system is undertaken. The inlet temperature of the liquid desiccant to the dehumidifier, space sensible heat ratio, and heat exchanger effectivenesses are the variables studied. Variations of these parameters and their effects on system performance are presented. Good system performance and energy saving could be achieved if proper values of these variables are selected. (Author)

  18. Experimental Performance of a Finned-tube Silica Gel Adsorption Chiller for Air-Conditioning Application

    Directory of Open Access Journals (Sweden)

    Mohammed A. Atiya

    2014-09-01

    Full Text Available This work presents the construction of a test apparatus for air-conditioning application that is flexible in changing a scaled down adsorbent bed modules. To improve the heat and mass transfer performance of the adsorbent bed, a finned-tube of the adsorbent bed heat exchanger was used. The results show that the specific cooling power (SCP and the coefficient of performance (COP are 163 W/kg and 0.16, respectively, when the cycle time is 40 min, the hot water temperature is 90oC, the cooling water temperature is 30oC and the evaporative water temperature is 11.4oC.

  19. Japanese power electronics inverter technology and its impact on the American air conditioning industry

    Energy Technology Data Exchange (ETDEWEB)

    Ushimaru, Kenji.

    1990-08-01

    Since 1983, technological advances and market growth of inverter- driven variable-speed heat pumps in Japan have been dramatic. The high level of market penetration was promoted by a combination of political, economic, and trade policies in Japan. A unique environment was created in which the leading domestic industries-- microprocessor manufacturing, compressors for air conditioning and refrigerators, and power electronic devices--were able to direct the development and market success of inverter-driven heat pumps. As a result, leading US variable-speed heat pump manufacturers should expect a challenge from the Japanese producers of power devices and microprocessors. Because of the vertically-integrated production structure in Japan, in contrast to the out-sourcing culture of the United States, price competition at the component level (such as inverters, sensors, and controls) may impact the structure of the industry more severely than final product sales. 54 refs., 47 figs., 1 tab.

  20. Distributed Air-Conditioning Energy Management System within the Smart Grid Context

    Institute of Scientific and Technical Information of China (English)

    A.H.Osman; A.R.Al-Ali; Haroon Khalil; Kiran Prem; Mursalin Haider; Mishal Eskander

    2014-01-01

    Air-conditioning (AC) systems are the major energy consumption units in residential and commercial buildings. In the context of smart grid, optimizing AC operations leads to substantial saving in energy consumption, reducing the consumer’s bill and contributing to the environment by minimizing carbon emissions from generating stations. This paper presents a distributed AC energy management system for buildings by using networked master-slaves controller architecture. The proposed system was designed, simulated, and experimentally tested by using real AC units in a students’ residence hall. Based on the students’ class schedules, several operational scenarios were implemented and tested. The proposed system implementation leads to a 40% to 60% saving of the consumed energy by the tested units. The same energy management scheme can be applied and implemented in other commercial and residential buildings.

  1. Efficient air conditioning. Part 2. Air quality; Effiziente Klimatisierung - Teil 2. Luftqualitaet

    Energy Technology Data Exchange (ETDEWEB)

    Haser, Herbert [Paul Wurth S.A., Luxembourg (Luxembourg)

    2002-05-01

    Like other air conditioning systems, solar air conditioners should provide 'dry cool air', i.e. hygienically acceptable air at a comfortable temperature. In the summer season and in big cities, this is not possible without air filtering and dehumidification. [German] Im Herbst vergangenen Jahres wurden in dieser Zeitschrift am Markt vorhandene Systeme fuer eine solargestuetzte Klimatisierung verglichen.In dem Artikel fordern die Verfasser 'trockene kuehle Luft fuer die Nutzer'. Diese Forderung sollte eigentlich lauten 'schadstoff- und staubarme Luft im Aufenthaltsbereiche mit Temperatur und Feuchte innerhalb des Behaglichkeitsfeldes' oder kurz gesagt: 'hygienisch einwandrei und angenehm temperiert'. Diese Forderung ist allerdings ohne eine Luftfilterung und ohne Entfeuchtung in den Innenstaedten im Sommer nicht realisierbar. (orig.)

  2. Development of air conditioning technologies to reduce CO2 emissions in the commercial sector

    Directory of Open Access Journals (Sweden)

    Yoshida Yukiko

    2006-10-01

    Full Text Available Abstract Background Architectural methods that take into account global environmental conservation generally concentrate on mitigating the heat load of buildings. Here, we evaluate the reduction of carbon dioxide (CO2 emissions that can be achieved by improving heating, ventilating, and air conditioning (HVAC technologies. Results The Climate Change Research Hall (CCRH of the National Institute for Environmental Studies (NIES is used as a case study. CCRH was built in line with the "Green Government Buildings" program of the Government Buildings Department at the Ministry of Land, Infrastructure and Transport in Japan. We have assessed the technology used in this building, and found that there is a possibility to reduce energy consumption in the HVAC system by 30%. Conclusion Saving energy reduces CO2 emissions in the commercial sector, although emission factors depend on the country or region. Consequently, energy savings potential may serve as a criterion in selecting HVAC technologies with respect to emission reduction targets.

  3. Application of a solar refrigeration system by absorption for the air conditioning of buildings

    Energy Technology Data Exchange (ETDEWEB)

    Machielsen, Cees H. M [Delft University of Technology, Mekelweg (Netherlands); Hagendijk, Andre E [Consultancy and Research (Netherlands)

    2000-07-01

    This paper describes the Sofri project, a cooperation between Ceeran Ltd and The Delft University of Technology. The main objective of this project is to develop the necessary knowledge and experience to commercialize solar-assisted air conditioning and dehumidification systems in the Dutch Caribbean. The project is motivated by the present needs of the Dutch Caribbean for renewable energy sources and the fact that the Caribbean has a high and uniform insolation throughout the year. Furthermore, hotels and offices in this area use more than 40% of their energy for air-conditioning purposes. Therefore solar-assisted air conditioning systems are a logic approach in reducing the energy demand and to lower the peak electricity reducing the energy demands for the local power station. Ceeran Ltd has the objective to reach full commercialization of the proposed technologies in the Dutch Caribbean. The research is concentrated on liquid absorption machines and solar collection systems such as flat plates with selective surfaces, heat pipe evacuated tubes flat plate collectors, and Compound Parabolic Concentrators. The first demonstration unit is planned to be installed in an office building in Curacao. The installation consists of a 35 kW LiBr/H{sub 2}O absorption machine driven by 100 m{sup 2} flat pate collectors with a gas backup system. The system will provide comfort air-conditioning for this these type of office buildings during daytime. [Spanish] Este documento describe el proyecto SOFRI, una cooperacion entre Ceeran, Ltd, y la Universidad Tecnologica del Delft. El principal objetivo de este proyecto es el de desarrollar el conocimiento necesario y la experiencia para comercializar los sistemas de aire acondicionado y deshumidificacion ayudados por la energia solar en el Caribe Holandes. Este proyecto ha sido motivado por las actuales necesidades del Caribe Holandes de fuentes de energia renovable y por el hecho de que el Caribe tiene una alta y uniforme insolacion

  4. Air conditioning of operating theatres - new strategies; OP-Klimatisierung im Umbruch

    Energy Technology Data Exchange (ETDEWEB)

    Teuber, M. [Ebert-Ingenieure, Nuernberg (Germany)

    2004-04-01

    New air conditioning strategies ensure more hygienic conditions, so that the 'protected area' becomes larger to include the whole inner working area. The result is a clean room of 3.2 x 3.2 m with a H14 filter, tissue outlet and lateral shielding which ensures laminar, low-turbulence displacement flow. (orig.) [German] Die lange bekannten Maengel bei der OP-Klimatisierung koennen nun mit Zustimmung der Hygiene beseitigt werden. Das logische System welches sich daraus ergibt, ist, dass der 'Schutzbereich', in dem operiert wird, wesentlich vergroessert wird, und damit den gesamten inneren Arbeitsbereich erfasst. Es wird ein Reinraumbereich von 3,20 x 3,20 m mit endstaendigem Flaechenfilter Klasse H14, Gewebeauslass und seitlicher Abschirmung geschaffen, welcher eine laminare turbulenzarme Verdraengungsstroemung gewaehrleistet. (orig.)

  5. Life cycle assessment of a conventional and plastic solar collector in alternative air-conditioning

    International Nuclear Information System (INIS)

    Alternative solar systems include a large number of heat-and mass exchange apparatus (HMTA) with considerable size surfaces. Prequired for realization of the work processes. This result in the increase in the overall dimentions. and cost of the system. The possibility of using the principle of combining the working and auxiliary processes within the (HMTA) has been considred, and the calculation proving the working ability of the alternative system for solving the task of air-condition, obtaining comfort parameters by employing evaporative air-cooling methods only, and a solar system with flat solar collectors to provide for the absorbent regeneration, have been performed. The study shows the importance in using Live Cycle Assessment, study for renewable energy, technologies, where environmental performance is especially important.(Author)

  6. Thermal design of a modern, air-conditioned, single-floor, solar-powered desert house

    KAUST Repository

    Serag-Eldin, M. A.

    2011-12-01

    The paper presents a thermal analysis of a single-floor, solar-powered desert house. The house is air-conditioned and provides all modern comforts and facilities. Electrical power, which drives the entire energy system, is generated by roof-mounted photovoltaic modules. The modules are fixed on special cradles which fold at night to expose the roof to the night sky, thereby enhancing night-time cooling, which is substantial in the desert environment. A detailed dynamic heat transfer analysis is conducted for the building envelope, coupled with a solar radiation model. Application to a typical Middle-Eastern desert site reveals that indeed such a design is feasible with present-day technology; and should be even more attractive with future advances in technology. © 2011 Copyright Taylor and Francis Group, LLC.

  7. Data mining based sensor fault diagnosis and validation for building air conditioning system

    International Nuclear Information System (INIS)

    A strategy based on the data mining (DM) method is developed to detect and diagnose sensor faults based on the past running performance data in heating, ventilating and air conditioning (HVAC) systems, combining a rough set approach and an artificial neural network (ANN). The reduced information is used to develop classification rules and train the neural network to infer appropriate parameters. The differences between measured thermodynamic states and predicted states obtained from models for normal performance (residuals) are used as performance indices for sensor fault detection and diagnosis. Real test results from a real HVAC system show that only the temperature and humidity measurements of many air handling units (AHU) can work very well as the measurements to distinguish simultaneous temperature sensor faults of the supply chilled water (SCW) and return chilled water (RCW)

  8. Numerical Analysis on Ventilating and Air Conditioning Scheme of Shenyang Subway Station

    Institute of Scientific and Technical Information of China (English)

    LI Wei; NA Yanling

    2007-01-01

    Different cities have different climate conditions and outdoor temperature and humidity, so the scheme of an environment control in subway should be analyzed by considering objective conditions, project cost and operating status. In this paper, a physical and mathematical model is built according to the design of Shenyang subway (line 1), the boundary conditions of the model are defined by the design and experiments, the numerical analysis of ventilating scheme and air conditioning scheme is introduced individually, and the temperature field and air flow field of the two schemes are compared, so that the feasibility of using a ventilating scheme in subway of northeast cities is discussed. Considering comfort and economy, it can be concluded that mechanical ventilation is feasible in subway of northeast cities because the air temperature there is not very high in summer.

  9. A thermodynamic evaluation of chilled water central air conditioning systems using artificial intelligence tools

    Directory of Open Access Journals (Sweden)

    Juan Carlos Armas

    2011-05-01

    Full Text Available  An analysis of a chilled water central air conditioning system is presented. The object was to calculate main cycle component irreversibility, as well as evaluating this indicator’s sensitivity to operational variations. Artificial neural networks (ANN, genetic algorithms (GA and Matlab tools were used to calculate refrigerant thermodynamic properties during each cycle stage. These tools interacted with equations describing the system’s thermodynamic behaviour. Refrigerant temperature, when released from the compressor, was determined by a hybrid model combining the neural model with a simple genetic algorithm used as optimisation tool; the cycle’s components which were most sensitive to changes in working conditions were identified. It was concluded that the compressor, evaporator and expansion mechanism (in that order represented significant exergy losses reaching 85.62% of total system irreversibility. A very useful tool was thus developed for evaluating these systems. 

  10. Optimization of recirculating laminar air flow in operating room air conditioning systems

    Directory of Open Access Journals (Sweden)

    Enver Yalcin

    2016-04-01

    Full Text Available The laminar flow air-conditioning system with 100% fresh air is used in almost all operating rooms without discrimination in Turkey. The laminar flow device which is working with 100% fresh air should be absolutely used in Type 1A operating rooms. However, there is not mandatory to use of 100% fresh air for Type 1B defined as places performed simpler operation. Compared with recirculating laminar flow, energy needs of the laminar flow with 100 % fresh air has been emerged about 40% more than re-circulated air flow. Therefore, when a recirculating laminar flow device is operated instead of laminar flow system with 100% fresh air in the Type 1B operating room, annual energy consumption will be reduced. In this study, in an operating room with recirculating laminar flow, optimal conditions have been investigated in order to obtain laminar flow form by analyzing velocity distributions at various supply velocities by using computational fluid dynamics method (CFD.

  11. Influence of Urban Microclimate on Air-Conditioning Energy Needs and Indoor Thermal Comfort in Houses

    Directory of Open Access Journals (Sweden)

    Feng-Chi Liao

    2015-01-01

    Full Text Available A long-term climate measurement was implemented in the third largest city of Taiwan, for the check of accuracy of morphing approach on generating the hourly data of urban local climate. Based on observed and morphed meteorological data, building energy simulation software EnergyPlus was used to simulate the cooling energy consumption of an air-conditioned typical flat and the thermal comfort level of a naturally ventilated typical flat. The simulated results were used to quantitatively discuss the effect of urban microclimate on the energy consumption as well as thermal comfort of residential buildings. The findings of this study can serve as a reference for city planning and energy management divisions to study urban sustainability strategies in the future.

  12. HVAC (heating, ventilation, air conditioning) literature in Japan: A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Hane, G.J.

    1988-02-01

    Japanese businessmen in the heating, ventilation, air conditioning, and refrigeration (HVACandR) industry consider the monitoring of technical and market developments in the United States to be a normal part of their business. In contrast, efforts by US businessmen to monitor Japanese HVAC and R developments are poorly developed. To begin to redress this imbalance, this report establishes the groundwork for a more effective system for use in monitoring Japanese HVAC and R literature. Discussions of a review of the principal HVAC and R publications in Japan and descriptions of the type of information contained in each of those publications are included in this report. Since the Japanese HVAC and R literature is abundant, this report also provides practical suggestions on how a researcher or research manager can limit the monitoring effort to the publications and type of information that would most likely be of greatest value.

  13. Study and Development of an Air Conditioning System Operating on a Magnetic Heat Pump Cycle

    Science.gov (United States)

    Wang, Pao-Lien

    1991-01-01

    This report describes the design of a laboratory scale demonstration prototype of an air conditioning system operating on a magnetic heat pump cycle. Design parameters were selected through studies performed by a Kennedy Space Center (KSC) System Simulation Computer Model. The heat pump consists of a rotor turning through four magnetic fields that are created by permanent magnets. Gadolinium was selected as the working material for this demonstration prototype. The rotor was designed to be constructed of flat parallel disks of gadolinium with very little space in between. The rotor rotates in an aluminum housing. The laboratory scale demonstration prototype is designed to provide a theoretical Carnot Cycle efficiency of 62 percent and a Coefficient of Performance of 16.55.

  14. Evaluation Framework and Analyses for Thermal Energy Storage Integrated with Packaged Air Conditioning

    Energy Technology Data Exchange (ETDEWEB)

    Kung, F.; Deru, M.; Bonnema, E.

    2013-10-01

    Few third-party guidance documents or tools are available for evaluating thermal energy storage (TES) integrated with packaged air conditioning (AC), as this type of TES is relatively new compared to TES integrated with chillers or hot water systems. To address this gap, researchers at the National Renewable Energy Laboratory conducted a project to improve the ability of potential technology adopters to evaluate TES technologies. Major project outcomes included: development of an evaluation framework to describe key metrics, methodologies, and issues to consider when assessing the performance of TES systems integrated with packaged AC; application of multiple concepts from the evaluation framework to analyze performance data from four demonstration sites; and production of a new simulation capability that enables modeling of TES integrated with packaged AC in EnergyPlus. This report includes the evaluation framework and analysis results from the project.

  15. A packed bed dehumidifier/regenerator for solar air conditioning with liquid desiccants

    Science.gov (United States)

    Factor, H. M.; Grossman, G.

    1980-01-01

    A packed column air-liquid contactor has been studied in application to air dehumidification and regeneration in solar air conditioning with liquid desiccants. A theoretical model has been developed to predict the performance of the device under various operating conditions. Computer simulations based on the model are presented which indicate the practical range of air to liquid flux ratios and associated changes in air humidity and desiccant concentration. An experimental apparatus has been constructed and experiments performed with Monoethylene Glycol (MEG) and Lithium Bromide as desiccants. MEG experiments have yielded inaccurate results and have pointed out some practical problems associated with the use of Glycols. LiBr experiments show very good agreement with the theoretical model. Preheating of the air is shown to greatly enhance desiccant regeneration. The packed column yields good results as a dehumidifier/regenerator, provided pressure drop can be reduced with the use of suitable packing.

  16. General collaboration offer of Johnson Controls regarding the performance of air conditioning automatic control systems and other buildings` automatic control systems

    Energy Technology Data Exchange (ETDEWEB)

    Gniazdowski, J.

    1995-12-31

    JOHNSON CONTROLS manufactures measuring and control equipment (800 types) and is as well a {open_quotes}turn-key{close_quotes} supplier of complete automatic controls systems for heating, air conditioning, ventilation and refrigerating engineering branches. The Company also supplies Buildings` Computer-Based Supervision and Monitoring Systems that may be applied in both small and large structures. Since 1990 the company has been performing full-range trade and contracting activities on the Polish market. We have our own well-trained technical staff and we collaborate with a series of designing and contracting enterprises that enable us to have our projects carried out all over Poland. The prices of our supplies and services correspond with the level of the Polish market.

  17. Development of Temperature-Humidity Independent Control Air-Conditioning Unit for Residential Buildings

    Institute of Scientific and Technical Information of China (English)

    HAN Xing; ZHANG Xu; LIU Jin-tao; GA Si-yun; KANG yue

    2009-01-01

    Cooling panels are increasingly used in domestic residential buildings.To provide medium temper-ature cold water for the cooling panel,and dehumidify the indoor air simultaneously,a new kind of temperature-humidity independent control air-conditioning unit was developed for single residential house by utilizing multi-variable technology.First,the supply air temperature was studied to determine the proper supply air flow rate for the humidity control.Then,the energy consumption of different temperature-humidity independent eontrol systems was studied.The analysis indicates that unity evaporating temperature can be used to handle the mois-ture load and sensible heat load in two evaporators.So the unit scheme was put forward.Two evaporators were used to produce medium temperature water and dry air separately,and electric expansion valves were used to control the refrigerant distribution between the two evaporators.Then, experimental work was carried out to in-vestigate the influence of compressor frequency,refrigerant distribution on the dehumidification capacity,energy efficiency and refrigeration capacity.In the end,the paper concludes that both compressor frequency and refrig-erant distribution can control the dehumidification capacity,but the former influences the EER more than the latter.while the latter influences the refrigeration capacity more than the former.We can find a proper running point at certain sensible and latent cooling load by adjusting both compressor frequency and electric expansion.valve.The energy consumption of this kind of unit was estimated and compared with present room air condition-ers,which shows that it can save about 41% cooling energy consumption.

  18. Research on frequency conversion technology of metro station's ventilation and air-conditioning system

    International Nuclear Information System (INIS)

    Ventilation and air-conditioning system (VAC) is the most energy-saving potential system in the metro. This paper analyzes the passenger traffic, air-conditioning load and station air supply on the initial, recent and long-term phase of metro station. And it proposes that it is necessary to run chilled-water pumps, air handing unit (AHU) fans and back/exhaust fans with frequency conversion technology (FCT). Then it uses the thermodynamic method to analyze the impact of running chilled-water pumps with FCT. The results show that running chilled-water pumps with FCT can reduce the total power consumption of system, although increases chiller energy consumption. Then the temperature and velocity fields of the platform and station hall are simulated by CFD software according to the variable air volume. And the results show that under the condition of running the VAC system with FCT, temperature and velocity fields distribution are both in the comfortable range. Finally, by taking a typical summer day for example, this paper analyzes the energy savings of chilled-water pumps, AHU fans and back/exhaust fans on the initial, recent and long-term phase, and the calculation results show that the respective total energy savings are 1103.4 kWh, 1064.3 kWh and 926.2 kWh, and the respective total power saving ratio is 73.4%, 71.2% and 59.5%. - Highlights: •Use the FCT to reduce energy consumption of metro VAC is necessary and possible. •Analyze the influence of running the chilled-water pumps with FCT. •Results show that variable air volume of station public area is feasible. •Calculations indicate that energy-saving effect of using the FCT is considerable

  19. A Mobile Air Conditioning System Operated by the Engine Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    Magnetto, D. [Centro Ricerche FIAT, Turin (Italy); De Boer, R. [ECN Efficiency and Infrastructure, Petten (Netherlands); Taklanti, A. [Valeo Systemes Thermiques SAS, Paris (France)

    2011-04-12

    This paper describes the development of a Mobile Air Conditioning (MAC) system with a very small impact on the environment. The system based on adsorption cooling is powered by the waste heat recovered from the engine coolant. The advantages of such a system are: a drastic reduction of the fuel overconsumption and the CO2 emission associated to the MAC usage, and the use of water as the refrigerant, which is a no Global Warming Potential (GWP) fluid compliant with the new EU regulation and naturally available. In addition the system being based on thermal compression and not on mechanical compression, is decoupled from the engine operation and has no impact on the vehicle handling. Finally, coupled with a small fuel burner or with a solar panel it can provide air conditioning when the vehicle engine is stop. Thus the system can provide the cabin preconditioning and allows the cabin cooling for those vehicles which are also used for rest or sleeping (truck, camper). The core of the system is an adsorption chiller that has been designed, manufactured and tested at first at the ECN laboratory. It produces 2 kW of chilling power with a COP of 0,4. The on board overall MAC system has been designed, manufactured and installed on a Fiat Grande Punto at CRF. The tests demonstrate the potential of such device to replace conventional vapor compression system. Following this experimental work a system redesign and car integration study was done and showed the potential to further reduce the volume and weight of the adsorption cooling system to the extent that the system can be integrated fully in the engine compartment.

  20. Open absorption system for cooling and air conditioning using membrane contactors - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Conde-Petit, M. [M. Conde Engineering, Zuerich (Switzerland); Weber, R.; Dorer, V. [Swiss Federal Laboratories for Materials Testing and Research (EMPA), Duebendorf (Switzerland)

    2008-07-01

    Air conditioning systems based upon the open absorption principle, essentially an absorption device operating at atmospheric pressure, have been proposed and investigated at many instances in the past eighty years. Their potential for improving energy efficiency is clearly recognized in the earliest research reports. By the mid 1950ies, solar thermal energy was being applied to drive open absorption-based air conditioning systems. For several reasons, however, the open absorption technology was not mature enough to take place in the mainstream. In the past two decades, vigorous efforts have been undertaken to reverse this situation, but success continued to elude, despite the fact that the main problems, such as corrosion, aerosols in the supply air, etc., have been identified. This report details the work and the main results from the MemProDEC Project. In this project innovative solutions were proposed, and successfully investigated, for the corrosion problem and the improvement of efficiency of the absorption process, in particular a new method to cool a very compact absorber. The practically uniform flow distribution for all three streams in the absorber (air, water and desiccant) warrants the contact of the air to be dehumidified with the desiccant over the whole surface of exchange (across a porous membrane). This, together with the cooling with water in counter flow to the air, are the key factors for the excellent effectiveness of the absorber. As the results show, the dehydration effectiveness of the prototype absorber is up to 150 % higher than that previously obtained by others. The solutions developed for compactness and modularity represent an important step in the way to flexible manufacturing, i.e. using a single element size to assemble autonomous air handling units of various nominal capacities. And although the manufacturing methods of the individual elements require improvement, namely by avoiding adhesive bonding, the choice of materials and the

  1. Performance evaluation of solar-assisted air-conditioning system with chilled water storage (CIESOL building)

    International Nuclear Information System (INIS)

    Highlights: ► We present a new solar-assisted air-conditioning system’s operation sequence. ► This mode considers the chilled water tanks action with variable-speed pump. ► It permits to save about 20% and 30% of energy and water consumption, respectively. ► It allows storing the excess cooling capacity of the absorption chiller. ► It prevents the sudden start/stop (on/off cycles) of the absorption chiller. - Abstract: This study presents the performance of solar-assisted air-conditioning system with two chilled water storage tanks installed in the Solar Energy Research Center building. The system consists mainly of solar collectors’ array, a hot-water driven absorption chiller, a cooling tower, two hot storage tanks, an auxiliary heater as well as two chilled storage tanks. The chilled water storage tank circuit was further investigated in order to find the optimum solar system’s operation sequence while providing the best energy performance. Firstly, we carried out a study about the dynamics of building’s cooling load and the necessity of the integration of chilled water storage tanks to solar system. Subsequently, the new system’s operation mode was proposed to reduce the energy consumption. The results demonstrate that we can save about 20% of the total energy consumption and about 30% of water consumption applying the new operation sequence, which takes into account the chilled water tanks action. Moreover, it was demonstrated that the integration of chilled water storage tanks allows to reduce the sudden absorption chiller on/off cycles, thereby improving the efficiency of the solar-assisted system.

  2. Emissions of halocarbons from mobile vehicle air conditioning system in Hong Kong

    Energy Technology Data Exchange (ETDEWEB)

    Yan, H.H.; Guo, H., E-mail: ceguohai@polyu.edu.hk; Ou, J.M.

    2014-08-15

    Highlights: • Halocarbon emissions from MVACS were characterized using bottom up approach. • Quantification of emission inventory was revealed using AUV Tools. • Potential emission reduction was estimated under 3 possible mitigation scenarios. • The results are useful for the policy makers to formulate and implement future phase-out schedule. - Abstract: During the implementation of Montreal Protocol, emission inventories of halocarbons in different sectors at regional scale are fundamental to the formulation of relevant management strategy and inspection of the implementation efficiency. This study investigated the emission profile of halocarbons used in the mobile vehicle air conditioning system, the leading sector of refrigeration industry in terms of the refrigerant bank, market and emission, in the Hong Kong Special Administrative Region, using a bottom-up approach developed by 2006 IPCC Good Practice Guidance. The results showed that emissions of CFC-12 peaked at 53 tons ODP (Ozone Depletion Potential) in 1992 and then gradually diminished, whereas HFC-134a presented an increasing emission trend since 1990s and the emissions of HFC-134a reached 65,000 tons CO{sub 2}-equivelant (CO{sub 2}-eq) by the end of 2011. Uncertainty analysis revealed relatively high levels of uncertainties for special-purpose vehicles and government vehicles. Moreover, greenhouse gas (GHG) abatements under different scenarios indicated that potential emission reduction of HFC-134a ranged from 4.1 to 8.4 × 10{sup 5} tons CO{sub 2}-eq. The findings in this study advance our knowledge of halocarbon emissions from mobile vehicle air conditioning system in Hong Kong.

  3. Dust deposition in ventilation and air-conditioning duct bend flows

    International Nuclear Information System (INIS)

    Highlights: ► We study particle deposition on the four inner surface of the duct bend. ► We analyse the effect of five ways of placements of the bend on particle deposition. ► Gravity and inertia force enhance the deposition as relaxation time rises. ► Deposition coefficient increases as air velocity or particle diameter increases. - Abstract: Particles carried by airflows in ventilation and air-conditioning systems have adverse effects on the quality of air in buildings and hence the health of building occupants. Gaining insight on particle deposition onto ventilation and air-conditioning duct bends is important for controlling pollutant dispersion. Based on the Reynolds stress transport model (RSM), this paper has taken into account the effects of drag, lift force, gravity, inertia force, turbulent diffusions, particle size and air velocity on the dimensionless deposition velocity of particles in smooth duct bends using fully developed velocity profiles. At two different air velocities of 3.0 m/s and 7.0 m/s, the aforementioned effects were predicted by Reynolds-averaged Navier–Stokes (RANS)-Lagrangian simulation on square shaped duct bends with different ways of placement. Preliminary results suggest that gravity and inertia force enhance the dimensionless deposition as dimensionless relaxation time rises. Change tendency of the dimensionless particle deposition velocity on different surfaces of bend duct agrees well with previous studies. As air velocity and particle diameter increase, a significant increase of particle deposition coefficient in the duct bends is observed. Particle deposition to intrados can be intensified by the combined action of gravity and inertia force in different direction.

  4. Lorentz-invariant and Lorentz-non-invariant aspects of a scalar tachyon field Lagrangian and the scalar tachyon Feynman propagator

    CERN Document Server

    Perepelitsa, Vassili F

    2016-01-01

    Some features of a Lorentz-violating (but Lorentz-covariant) Lagrangian of a scalar tachyon field are considered in this note. It is shown that the equation of motion and the Feynman propagator resulting from it are Lorentz-invariant, while the Lorentz symmetry of the suggested tachyon field model can be defined as spontaneously broken.

  5. Test of Lorentz Invarience from Compton Scattering

    CERN Document Server

    Mohanmurthy, Prajwal; Narayan, Amrendra

    2015-01-01

    In the recent times, test of Lorentz Invariance has been used as a means to probe theories of physics beyond the standard model, especially those such as extensions to String Theory and Quantum Gravity. Tests of Lorentz invariance could go a long way in setting the stage for possible quantum gravity theories which are beyond the standard model. We describe a simple way of utilizing the polarimeters, which are a critical beam instrument at precision and intensity frontier nuclear physics labs such as Stanford Linear Accelerator Center (SLAC) and Jefferson Lab (JLab), to limit the dependence of speed of light with the energy of the photons. Furthermore, we also describe a way of limiting directional dependence of speed of light at previously unprecedented levels of precision by studying the sidereal variations. We obtain a limit of MSME parameters: $\\sqrt{\\kappa_X^2 + \\kappa_Y^2} < 2.4 \\times 10^{-17}$ and $\\sqrt{\\left( 2c_{TX} - (\\tilde{\\kappa}_{0^+}^{YZ} \\right)^2 + \\left( 2c_{TY} - (\\tilde{\\kappa}_{0^+}^{...

  6. Lorentz invariance of the extended object

    International Nuclear Information System (INIS)

    It has been known for a few years that the Heisenberg field of the extended object can be obtained in expanded form as a power series of quantum operators and creation and annihilation operators by solving the Yang-Feldam equation. Such an expression is called a dynamical map (mapping of the infield into the Heisenberg field). We will show that the Heisenberg field thus expressed (the dynamical map) is Lorentz covariant if it satisfies the equal time canonical commutation relation. In this paper we limit ourselves to the invariance of the first order term. Also our Heisenberg field is (1+1) dimensional and is of the tree approximation. In the course of the calculation, we find that the quantum mechanical operator and the quantized field are mixed by the Lorentz transformation if the space derivative of the classical field soliton solution is assumed to decrease not faster than 1/x2. It indicates that the Hilbert space is not the direct product of two sub-Hilbert spaces, even though it is a product of two subspaces one of which is a Fock space of the quantized field and the other is of the quantum mechanical operator

  7. Testing Lorentz symmetry with Lunar Laser Ranging

    CERN Document Server

    Bourgoin, A; Bouquillon, S; Poncin-Lafitte, C Le; Francou, G; Angonin, M -C

    2016-01-01

    Lorentz symmetry violations can be parametrized by an effective field theory framework that contains both General Relativity (GR) and the Standard Model of particle physics called the Standard-Model Extension (SME). We present new constraints on pure gravity SME coefficients obtained by analyzing Lunar Laser Ranging (LLR) observations. We use a new numerical lunar ephemeris computed in the SME framework and we perform a LLR data analysis using a set of 20721 normal points covering the period August 1969 to December 2013. We emphasize that linear combination of SME coefficients to which LLR data are sensitive are not the same as those fitted in previous post-fit residuals analysis using LLR observations and based on theoretical grounds. We found no evidence for Lorentz violation at the level of $10^{-8}$ for $\\bar{s}^{TX}$, $10^{-12}$ for $\\bar{s}^{XY}$ and $\\bar{s}^{XZ}$, $10^{-11}$ for $\\bar{s}^{XX}-\\bar{s}^{YY}$ and $\\bar{s}^{XX}+\\bar{s}^{YY}-2\\bar{s}^{ZZ}-0.045\\bar{s}^{YZ}$ and $10^{-9}$ for $\\bar{s}^{TY}+...

  8. Bigravity and Lorentz-violating Massive Gravity

    CERN Document Server

    Blas, D; Garriga, J

    2007-01-01

    Bigravity is a natural arena where a non-linear theory of massive gravity can be formulated. If the interaction between the metrics $f$ and $g$ is non-derivative, spherically symmetric exact solutions can be found. At large distances from the origin, these are generically Lorentz-breaking bi-flat solutions (provided that the corresponding vacuum energies are adjusted appropriately). The spectrum of linearized perturbations around such backgrounds contains a massless as well as a massive graviton, with {\\em two} physical polarizations each. There are no propagating vectors or scalars, and the theory is ghost free (as happens with certain massive gravities with explicit breaking of Lorentz invariance). At the linearized level, corrections to GR are proportional to the square of the graviton mass, and so there is no vDVZ discontinuity. Surprisingly, the solution of linear theory for a static spherically symmetric source does {\\em not} agree with the linearization of any of the known exact solutions. The latter c...

  9. Bigravity and Lorentz-violating massive gravity

    International Nuclear Information System (INIS)

    Bigravity is a natural arena where a nonlinear theory of massive gravity can be formulated. If the interaction between the metrics f and g is nonderivative, spherically symmetric exact solutions can be found. At large distances from the origin, these are generically Lorentz-breaking bi-flat solutions (provided that the corresponding vacuum energies are adjusted appropriately). The spectrum of linearized perturbations around such backgrounds contains a massless as well as a massive graviton, with two physical polarizations each. There are no propagating vectors or scalars, and the theory is ghost free (as happens with certain massive gravities with explicit breaking of Lorentz invariance). At the linearized level, corrections to general relativity are proportional to the square of the graviton mass, and so there is no van Dam-Veltam-Zakharov discontinuity. Surprisingly, the solution of linear theory for a static spherically symmetric source does not agree with the linearization of any of the known exact solutions. The latter coincide with the standard Schwarzschild-(anti)-de Sitter solutions of general relativity, with no corrections at all. Another interesting class of solutions is obtained where f and g are proportional to each other. The case of bi-de Sitter solutions is analyzed in some detail

  10. Characteristic Evaluation on the Cooling Performance of an Electrical Air Conditioning System Using R744 for a Fuel Cell Electric Vehicle

    OpenAIRE

    Moo-Yeon Lee; Hong-Phil Won; Ho-Seong Lee

    2012-01-01

    The objective of this study was to investigate the cooling performance characteristics of an electrical air conditioning system using R744 as an alternative of R-134a for a fuel cell electric vehicle. In order to analyze the cooling performance characteristics of the air conditioning system using R744 for a fuel cell electric vehicle, an electrical air conditioning system using R744 was developed and tested under various operating conditions according to both inlet air conditions of the gas c...

  11. The hardware design of Control System of the Solar-assisted Air Conditioning for Pure Electric Vehicle%纯电动汽车太阳能辅助空调控制系统的硬件设计

    Institute of Scientific and Technical Information of China (English)

    孙浩; 黄菊花

    2012-01-01

    Pure electric vehicle car battery is the only source of power and very limited,auxiliary equipment reduce power consumption of the driving distance of Pure electric vehicles, especially air conditioning, so development of efficient Pure electric car air- conditioning systems is the key step for electric car can be accepted in business, the car roof is full covered with solar cells, air- conditioning system can increase the cooling capacity , while increasing driving distance of Pure electric vehicles. In this paper, studied solar-assisted air conditioning system to small Pure electric vehicles, designed for the air conditioning control system for Pure electric vehicles to create a more comfortable driving and riding environment.%纯电动汽车车载动力电池是其唯一的动力源且很有限,辅助设备消耗的电能减少了纯电动汽车的续驶里程,尤其是空调,所以开发高效的纯电动汽车空调系统是纯电动汽车能够被市场接受的关键。将纯电动汽车顶盖布满太阳电池,可以使空调系统的制冷能力增强,同时还能增加纯电动汽车的行驶距离。对小型纯电动汽车的太阳能辅助空调系统进行研究,设计出适合该空调的自动控制系统,可为纯电动汽车创造出一个更加舒适的驾驶和乘座环境。

  12. 40 CFR 86.162-00 - Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2.

    Science.gov (United States)

    2010-07-01

    ... Procedures § 86.162-00 Approval of alternative air conditioning test simulations and descriptions of AC1 and AC2. The alternative air conditioning test procedures AC1 and AC2 are approved by the Administrator... requirements of paragraph (a) of this section and meet the requirements of § 86.163-00. Air conditioning...

  13. Energy performance and optimal control of air-conditioned buildings with envelopes enhanced by phase change materials

    International Nuclear Information System (INIS)

    Highlights: → Impact of PCM on the energy consumption and peak load demand as well as electricity cost of air-conditioned buildings. → Impact of load shifting control on energy consumption, peak load and electricity cost of air-conditioned PCM buildings. → Impact of demand limiting control on energy consumption, peak load and electricity cost of air-conditioned PCM buildings. → Energy/cost effects of different control strategies and use of PCM in energy-plus-demand-based pricing policy. → Energy/cost effects of different control strategies and use of PCM in time-based pricing policy. - Abstract: Studies are conducted to investigate the impacts of shape-stabilized phase change material (SSPCM) and different control strategies on the energy consumption and peak load demand as well as electricity cost of building air-conditioning systems at typical summer conditions in two climates (subtropical and dry continental climates). An office building using a typical variable air volume (VAV) air-conditioning system was selected and simulated as the reference building in this study. Its envelopes were enhanced by integrating the SSPCM layers into its walls while the air-conditioning system and other configurations of the building remained unchanged. The building system was tested under two typical weather conditions and two typical electricity pricing policies (i.e. time-based pricing and energy-plus-demand-based pricing). Test results show that the use of SSPCM in the building could reduce the building electricity cost significantly (over 11% in electricity cost reduction and over 20% in peak load reduction), under two pricing policies by using load shifting control and demand limiting control respectively. This paper presents the test results and the evaluation on the energy performance and the optimal control strategies of air-conditioned commercial buildings with envelopes enhanced by SSPCM.

  14. Lorentz violation correction to the Aharonov-Bohm scattering

    Science.gov (United States)

    Anacleto, M. A.

    2015-10-01

    In this paper, using a (2 +1 )-dimensional field theory approach, we study the Aharonov-Bohm (AB) scattering with Lorentz symmetry breaking. We obtain the modified scattering amplitude to the AB effect due to the small Lorentz violation correction in the breaking parameter and prove that up to one loop the model is free from ultraviolet divergences.

  15. Lorentz violation correction to the Aharonov-Bohm scattering

    CERN Document Server

    Anacleto, M A

    2015-01-01

    In this paper, using a (2+1)-dimensional field theory approach we study the Aharonov-Bohm (AB) scattering with Lorentz symmetry breaking. We obtain the modified scattering amplitude to the AB effect due to the small Lorentz violation correction in breaking parameter and prove that up to one-loop the model is free from ultraviolet divergences.

  16. Limits on Lorentz violation in neutral-Kaon decay

    CERN Document Server

    Vos, K K; Timmermans, R G E

    2013-01-01

    The KLOE collaboration recently reported bounds on the directional dependence of the lifetime of the short-lived neutral kaon K_S with respect to the cosmic microwave background dipole anisotropy. We interpret their results in a general framework developed to probe Lorentz violation in the weak interaction. In this approach a Lorentz-violating tensor \\chi_{\\mu\

  17. Introduction to Ives' 'Derivation of the Lorentz transformations'

    International Nuclear Information System (INIS)

    Lorentz ether theory is elevated on a par with special relativity by Ives' derivation of the Lorentz transformations. The two theories combined then demand the physical existence of a relativistic ether. This is supported by the still unfolding hierarchy of matter. Cogent implications for physical theory follow. (Auth.)

  18. Discussion on Neutrino Oscillation and CPT/Lorentz Invariance Violation

    CERN Document Server

    Luo, Cui-Bai; Du, Yi-Lun; Wang, Yong-Long; Zong, Hong-Shi

    2016-01-01

    Depending on deformed canonical anticommutation relations, massless neutrino oscillation based on CPT /Lorentz invariance viol ation is discussed. It is found that the deformed canonical anti-commutation relations should satisfy the condition of new Moy al product and new non standard commutation relations. Furthermore, by comparing the neutrino experimental data and the above relations, we find that the orders of magnitude of noncommutative parameters or Lorentz invariant Violation parameters $\\mathi t{A}$ is not self-consistent. This means that the previous studies about Lorentz invariance violation in noncommutative field theory may not naturally explain massless neutrino oscillation. In other words, it should be impossible to explain neutrino os cillation by lorentz invariance violation. This conclusion is supported by the latest atmospheric neutrinos experimental resul ts from Super-Kamiokande Collaboration, which show that no evidence of Lorentz invariance violation on atmospheric neutrinos w as observe...

  19. Online optimal control of variable refrigerant flow and variable air volume combined air conditioning system for energy saving

    International Nuclear Information System (INIS)

    The variable refrigerant flow (VRF) and variable air volume (VAV) combined air conditioning system can solve the problem of the VRF system in outdoor air ventilation while taking advantage of its high part load energy efficiency. Energy performance of the combined air conditioning system can also be optimized by joint control of both the VRF and the VAV parts. A model-based online optimal control strategy for the combined air conditioning system is presented. Simplified adaptive models of major components of the combined air conditioning system are firstly developed for predicting system performances. And a cost function in terms of energy consumption and thermal comfort is constructed. Genetic algorithm is used to search for the optimal control sets. The optimal control strategy is tested and evaluated through two case studies based on the simulation platform. Results show that the optimal strategy can effectively reduce energy consumption of the combined air conditioning system while maintaining acceptable thermal comfort. - Highlights: • A VRF and VAV combined system is proposed. • A model-based online optimal control strategy is proposed for the combined system. • The strategy can reduce energy consumption without sacrificing thermal comfort. • Novel simplified adaptive models are firstly developed for the VRF system

  20. Lorentz invariance without trans-Planckian physics?

    International Nuclear Information System (INIS)

    We explore the possibility that, in a quantum field theory with Planck scale cutoff Λ≃mp, observable quantities for low-energy processes respect the Lorentz symmetry. In particular, we compute the one-loop radiative correction Π to the self-energy of a scalar field with λϕ4 interaction, using a modified (non-invariant) propagator which vanishes in the trans-Planckian regime, as expected in the “classicalisation” scenario. We then show that, by imposing the result does not depend on Λ (in the limit Λ→mp), an explicit (albeit not unique) expression for Π can be derived, which is similar to the one simply obtained with the standard Feynman propagator and a cutoff Λ=mp

  1. Living with ghosts in Lorentz invariant theories

    Energy Technology Data Exchange (ETDEWEB)

    Garriga, Jaume [Departament de Física Fonamental i Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Vilenkin, Alexander, E-mail: jaume.garriga@ub.edu, E-mail: vilenkin@cosmos.phy.tufts.edu [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)

    2013-01-01

    We argue that theories with ghosts may have a long lived vacuum state even if all interactions are Lorentz preserving. In space-time dimension D = 2, we consider the tree level decay rate of the vacuum into ghosts and ordinary particles mediated by non-derivative interactions, showing that this is finite and logarithmically growing in time. For D > 2, the decay rate is divergent unless we assume that the interaction between ordinary matter and the ghost sector is soft in the UV, so that it can be described in terms of non-local form factors rather than point-like vertices. We provide an example of a nonlocal gravitational-strength interaction between the two sectors, which appears to satisfy all observational constraints.

  2. Testing Lorentz symmetry with planetary orbital dynamics

    CERN Document Server

    Hees, Aurélien; Poncin-Lafitte, Christophe Le; Bourgoin, Adrien; Rivoldini, Attilio; Lamine, Brahim; Meynadier, Frédéric; Guerlin, Christine; Wolf, Peter

    2015-01-01

    Planetary ephemerides are a very powerful tool to constrain deviations from the theory of General Relativity using orbital dynamics. The effective field theory framework called the Standard-Model Extension (SME) has been developed in order to systematically parametrize hypothetical violations of Lorentz symmetry (in the Standard Model and in the gravitational sector). In this communication, we use the latest determinations of the supplementary advances of the perihelia and of the nodes obtained by planetary ephemerides analysis to constrain SME coefficients from the pure gravity sector and also from gravity-matter couplings. Our results do not show any deviation from GR and they improve current constraints. Moreover, combinations with existing constraints from Lunar Laser Ranging and from atom interferometry gravimetry allow us to disentangle contributions from the pure gravity sector from the gravity-matter couplings.

  3. Universal Gravitation as Lorentz-covariant Dynamics

    CERN Document Server

    Kauffmann, Steven Kenneth

    2014-01-01

    Einstein's equivalence principle implies that the acceleration of a particle in a "specified" gravitational field is independent of its mass. While this is certainly true to great accuracy for bodies we observe in the Earth's gravitational field, a hypothetical body of mass comparable to the Earth's would perceptibly cause the Earth to fall toward it, which would feed back into the strength as a function of time of the Earth's gravitational field affecting that body. In short, Einstein's equivalence principle isn't exact, but is an approximation that ignores recoil of the "specified" gravitational field, which sheds light on why general relativity has no clearly delineated native embodiment of conserved four-momentum. Einstein's 1905 relativity of course doesn't have the inexactitudes he unwittingly built into GR, so it is natural to explore a Lorentz-covariant gravitational theory patterned directly on electromagnetism, wherein a system's zero-divergence overall stress-energy, including all gravitational fee...

  4. IEA SHC Task 38 'Solar air-conditioning and refrigeration'. Danish participation 2007-2010. Appendix; IEA SHC Task 38 'Solar air-conditioning and refrigeration'. Dansk deltagelse 2007-2010. Bilag

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, Aarhus (Denmark)); Muenster, E. (PlanEnergi, Skoerping (Denmark)); Reinholdt, L. (Teknologisk Institut, Aarhus (Denmark)); Munds, S. (AC-Sun Aps, Horsens (Denmark))

    2011-03-15

    IEA SHC Task 38 'Solar Air-Conditioning and Refrigeration' ran from October 2006 to December 2010. Denmark was represented in the task from January 2007 to December 2010. The aim of the task was to encourage use of solar powered refrigeration and air conditioning systems in particular at residential, commercial and industrial sectors. Furthermore, the aim was to contribute to new research and development activities on new systems and concepts. The appendix contains the publications prepared by the Danish project group.(LN)

  5. Indoor Air quality related to occupancy at an air-conditioned public building

    Directory of Open Access Journals (Sweden)

    Karina Ponsoni

    2010-02-01

    Full Text Available To characterize the influence of occupancy on the indoor air quality, a public office building with air-conditioning system was selected for this study. The indoor parameters included total bacteria count, total fungal count, temperature, relative humidity, and carbon dioxide concentration. The number of occupants, which varied throughout the day, was recorded in each sample. The samples were taken before the beginning of the working day and during 3 h, at an interval of 30 min between each sampling, and continued for five working days during a week. Correlation analysis demonstrated that occupancy rates were positively correlated with airborne bacteria, CO2, and temperature. No significant association between the number of occupants and fungus was observed. The results of this study provided information on the variability of indoor air parameters during the time-varying occupancy over the course of the day in at air-conditioned buildings where occupancy was quite dynamic.Com o objetivo de caracterizar a influência da ocupação na qualidade do ar interior, um edifício público com sistema de ar condicionado foi selecionado. As variáveis ambientais consideradas incluíram contagem total de bactérias e fungos, temperatura, umidade relativa e concentração de dióxido de carbono. O número de ocupantes, que variou durante todo o dia, foi estimado em cada amostragem. As amostras foram coletadas antes do início do expediente de trabalho e durante 3 horas, em intervalos de 30 minutos, por 5 dias úteis consecutivos. A análise de correlação demonstrou que a taxa de ocupação foi correlacionada positivamente com a concentração de bactérias, dióxido de carbono e temperatura. Nenhuma associação significativa foi observada entre o número de ocupantes e concentração de fungos. Os resultados deste estudo fornecem informações quanto à variabilidade nos parâmetros do ar interior no decorrer do dia em um edifício onde a ocupação

  6. Ant-nest corrosion of copper tubing in air-conditioning units

    Directory of Open Access Journals (Sweden)

    Bastidas, D. M.

    2006-10-01

    Full Text Available Ant-nest corrosion is a specific type of premature failure (2-3 months of copper tubes used in air-conditioning units causing the loss of refrigerant liquid and the consequent environment pollution. It is known that attack requires the simultaneous presence of moisture, oxygen and a corrodent, usually an organic acid, such as formic, acetic, propionic or butyric acid or other volatile organic substances like methanol, ethanol, formaldehyde or acetoaldehyde. Approximately 10% of all premature failures of copper tubes used in the heating, ventilation and air-conditioning (HVAC industry are the result of ant-nest corrosion. This type of corrosion usually occurs in thin-wall copper pipes, especially when copper is de-sulphurised, and is known by several names: formicary corrosion, unusual corrosion, branched pits, pinhole corrosion, etc.

    Corrosión por “nido de hormigas” es un tipo específico de fallo prematuro (2-3 meses que tiene lugar en tubos de cobre utilizados en sistemas de aire acondicionado originando la pérdida de líquido refrigerante y la consecuente contaminación ambiental. Es conocido que este tipo de ataque requiere la presencia simultánea de humedad, oxígeno y un medio agresivo, habitualmente un ácido orgánico, como fórmico, acético  propiónico o butírico u otras sustancias orgánicas volátiles tales como metanol, etanol, formaldehido o acetoaldehido. Aproximadamente el 10% de los fallos prematuros en tubos de cobre utilizados en calefacción, ventilación y en la industria de aire acondicionado son el resultado de corrosión por nido de hormigas. Frecuentemente, este tipo de corrosión tiene lugar en tubos de cobre de pared delgada, especialmente cuando el cobre es del tipo desulfurizado, y se conoce con varios nombres: corrosión por ácido fórmico, corrosión no habitual, picaduras ramificadas, corrosión con forma de alfiler, etc.

  7. Lorentz invariance violation and generalized uncertainty principle

    Science.gov (United States)

    Tawfik, Abdel Nasser; Magdy, H.; Ali, A. Farag

    2016-01-01

    There are several theoretical indications that the quantum gravity approaches may have predictions for a minimal measurable length, and a maximal observable momentum and throughout a generalization for Heisenberg uncertainty principle. The generalized uncertainty principle (GUP) is based on a momentum-dependent modification in the standard dispersion relation which is conjectured to violate the principle of Lorentz invariance. From the resulting Hamiltonian, the velocity and time of flight of relativistic distant particles at Planck energy can be derived. A first comparison is made with recent observations for Hubble parameter in redshift-dependence in early-type galaxies. We find that LIV has two types of contributions to the time of flight delay Δ t comparable with that observations. Although the wrong OPERA measurement on faster-than-light muon neutrino anomaly, Δ t, and the relative change in the speed of muon neutrino Δ v in dependence on redshift z turn to be wrong, we utilize its main features to estimate Δ v. Accordingly, the results could not be interpreted as LIV. A third comparison is made with the ultra high-energy cosmic rays (UHECR). It is found that an essential ingredient of the approach combining string theory, loop quantum gravity, black hole physics and doubly spacial relativity and the one assuming a perturbative departure from exact Lorentz invariance. Fixing the sensitivity factor and its energy dependence are essential inputs for a reliable confronting of our calculations to UHECR. The sensitivity factor is related to the special time of flight delay and the time structure of the signal. Furthermore, the upper and lower bounds to the parameter, a that characterizes the generalized uncertainly principle, have to be fixed in related physical systems such as the gamma rays bursts.

  8. A review on the recent development of solar absorption and vapour compression based hybrid air conditioning with low temperature storage

    Directory of Open Access Journals (Sweden)

    Noor D. N.

    2016-01-01

    Full Text Available Conventional air conditioners or vapour compression systems are main contributors to energy consumption in modern buildings. There are common environmental issues emanating from vapour compression system such as greenhouse gas emission and heat wastage. These problems can be reduced by adaptation of solar energy components to vapour compression system. However, intermittence input of daily solar radiation was the main issue of solar energy system. This paper presents the recent studies on hybrid air conditioning system. In addition, the basic vapour compression system and components involved in the solar air conditioning system are discussed. Introduction of low temperature storage can be an interactive solution and improved economically which portray different modes of operating strategies. Yet, very few studies have examined on optimal operating strategies of the hybrid system. Finally, the findings of this review will help suggest optimization of solar absorption and vapour compression based hybrid air conditioning system for future work while considering both economic and environmental factors.

  9. Potential energy savings and environmental impacts of energy efficiency standards for vapor compression central air conditioning units in China

    Energy Technology Data Exchange (ETDEWEB)

    Lu Wei [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084 (China)]. E-mail: tjluwei@163.com

    2007-03-15

    Owing to the rapid development of economy and the stable improvement of people's living standard, central air conditioning units are broadly used in China. This not only consumes large energy, but also results in adverse energy-related environmental issues. Energy efficiency standards are accepted effective policy tools to reduce energy consumption and pollutant emissions. Recently, China issued two national energy efficiency standards, GB19577-2004 and GB19576-2004, for vapor compression central air conditioning units for the first time. This paper first reviews the two standards, and then establishes a mathematic model to evaluate the potential energy savings and environmental impacts of the standards. The estimated results indicate implementing these standards will save massive energy, as well as benefit greatly to the environment. Obviously, it is significant to implement energy efficiency standards for central air conditioning units in China.

  10. Adsorption cold storage system with zeolite-water working pair used for locomotive air conditioning

    International Nuclear Information System (INIS)

    Adsorption cold storage has lately attracted attention for its large storage capacity and zero cold energy loss during the storing process. Thermodynamic and experimental studies on the cold storage capacity and the cold discharging process, in which the adsorber is either air cooled or adiabatic, have been presented. An adsorption cold storage system with zeolite-water working pair has been developed, and some operating results are summarized. This system is used for providing air conditioning for the driver's cab of an internal combustion locomotive. Unlike a normal adsorption air conditioner, the system starts running with the adsorption process, during which the cold energy stored is discharged, and ends running with the generation process. The adsorbent temperature decreases during the cold storing period between two runs. The refrigeration power output for the whole running cycle is about 4.1 kW. It appears that such a system is quite energetically efficient and is comparatively suitable for providing discontinuous refrigeration capacity when powered by low grade thermal energy, such as industrial exhausted heat or solar energy

  11. Development of High Speed Inverter Rotary Compressor for the Air-conditioning System

    Science.gov (United States)

    Kang, Seoung-Min; Yang, Eun-soo; Shin, Jin-Ung; Park, Joon-Hong; Lee, Se-Dong; Ha, Jong-Hun; Son, Young-Boo; Lee, Byeong-Chul

    2015-08-01

    In order to meet the various operating loads of an air-conditioning system, an inverter compressor with a wide operational range is necessary. One of the ways to achieve a wide operation range is to drive a small capacity compressor at high speed. Moreover, it is possible to maximize the efficiency in part-load operation condition close to actual operating conditions and to reduce the cost by compact design of a small capacity compressor. In addition, the shortage of maximum capacity, due to the small rated capacity, is covered through high speed operation. However, in general, if the compressor operates at high speed, problems occurs such as reduced efficiency due to friction, increased noise, increased amount of oil discharge and decreased durability of the main components. In order to solve these problems the following have been investigated: optimized dimension parameters of the compression chamber, enhanced shaft design and the structure for the reduction of oil discharge and noise at high speed operation. Finally the high speed inverter rotary compressor with high efficiency and more compact size has been developed as compared with the conventional rotary compressor.

  12. New Automotive Air Conditioning System Simulation Tool Developed in MATLAB/Simulink

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, T.; Chaney, L.; Meyer, J.

    2013-07-01

    Further improvements in vehicle fuel efficiency require accurate evaluation of the vehicle's transient total power requirement. When operated, the air conditioning (A/C) system is the largest auxiliary load on a vehicle; therefore, accurate evaluation of the load it places on the vehicle's engine and/or energy storage system is especially important. Vehicle simulation software, such as 'Autonomie,' has been used by OEMs to evaluate vehicles' energy performance. A transient A/C simulation tool incorporated into vehicle simulation models would also provide a tool for developing more efficient A/C systems through a thorough consideration of the transient A/C system performance. The dynamic system simulation software Matlab/Simulink was used to develop new and more efficient vehicle energy system controls. The various modeling methods used for the new simulation tool are described in detail. Comparison with measured data is provided to demonstrate the validity of the model.

  13. Exergy analysis of a novel configuration of desiccant based evaporative air conditioning system

    International Nuclear Information System (INIS)

    Highlights: • A procedure is developed for exergy analyses of the system. • The exergy transports between the components are determined. • The exergy efficiency of the whole system is 40.7% at 15 °C reference temperature. - Abstract: In this work, a process is developed for exergy analyses of a novel configuration of desiccant based an evaporative air conditioning system. The exergy transfer and destruction between the components of the system are defined for the average measured variables obtained from the experimental results. The exergy formulations are carried out to the experimental system using the data collected during a typical operation of the system. The exergy output, specific flow exergy, exergy destruction, exergy input and exergy efficiency are determined. Furthermore, the sustainability assessment and relative irreversibility of components are obtained. It is found that the exergy efficiency of the entire experimental unit is 40.7% at a reference temperature of 15 °C. It is also observed that the exergy efficiencies of the entire system varies between 56% and 25% for reference temperature of 0–30 °C, respectively. The effects of reference temperature on the performance of the studied system are investigated. Based on the investigation, it is seen that an exergy analysis can provide beneficial knowledge with respect to the theoretical upper limit of the system performance

  14. Experimental evaluation of automotive air-conditioning using HFC-134a and HC-134a

    Science.gov (United States)

    Nasution, Henry; Zainudin, Muhammad Amir; Aziz, Azhar Abdul; Latiff, Zulkarnain Abdul; Perang, Mohd Rozi Mohd; Rahman, Abd Halim Abdul

    2012-06-01

    An experimental study to evaluate the energy consumption of an automotive air conditioning is presented. In this study, these refrigerants will be tested using the experimental rig which simulated the actual cars as a cabin complete with a cooling system component of the actual car that is as the blower, evaporator, condenser, radiators, electric motor, which acts as a vehicle engine, and then the electric motor will operate the compressor using a belt and pulley system, as well as to the alternator will recharge the battery. The compressor working with the fluids HFC-134a and HC-134a and has been tested varying the speed in the range 1000, 1500, 2000 and 2500 rpm. The measurements taken during the one hour experimental periods at 2-minutes interval times for temperature setpoint of 20°C with internal heat loads 0, 500, 700 and 1000 W. The final results of this study show an overall better energy consumption of the HFC-134a compared with the HC-134a.

  15. Passive cooling for air-conditioning energy savings with new radiative low-cost coatings

    Energy Technology Data Exchange (ETDEWEB)

    Muselli, Marc [University of Corsica - UMR CNRS 6134, Vignola, Route des Sanguinaires, F-20000 Ajaccio (France)

    2010-06-15

    Passive cooling is considered as an alternative technology to avoid unwanted heat gains, to reduce urban heat islands and to generate cooling potential for buildings (limiting air-conditioning energy). According to materials and surface treatments, the roof can represent to be a major heat gain source from opaque elements of the building fabric, heating up the outer surface and increasing heat flow by conduction. This paper presents low-cost new radiative materials (1 Euro /m{sup 2}) allowing to limit heat gains during diurnal cycle for hot seasons. To evaluate the relevance of these new substrates, their reflective UV-VIS-IR behavior are studied and compared to classical roofed materials available in industrial and developing countries. A 48 m{sup 2} experimental roof having different surfaces (plate steel sheets, fiber cement, terra cotta tiles and corrugated sheets) allows to determine the temperature ratio {delta} between uncoated and coated materials. Up to 34% surface temperature gains are obtained for white coated CS, 25% for FC and {approx}18% for TCT and PSS. According to uncoated materials for a surface temperature T{sub 0} = 60 C, simulations showed that the low-cost white opaque reflective roofs (50 m{sup 2}) presented in this study would reduce cooling energy consumption by 26-49%. (author)

  16. Modeling and simulation of a solar powered two bed adsorption air conditioning system

    International Nuclear Information System (INIS)

    A simple lumped parameter model is established to investigate the performance of a solar powered adsorption air conditioning system driven by flat-type solar collectors with three different configurations of glazes: (i) single glazed cover; (ii) double glazed cover and (iii) transparent insulation material (TIM) cover. The dynamic performance of a continuous adsorption cycle using a double adsorber along with heat recovery is measured in terms of the temperature histories, gross solar coefficient of performance and specific cooling power. Also, the influences of some important design and operational parameters on the performance of the system are studied. It is found that the chosen three types of collector configurations make no big difference on the performance, but the adsorbent mass and lumped capacitance have significant effects on the system performance as well as on the system size. Simulation results indicate that the effect of overall heat transfer coefficient is not predominant if the cycle duration is longer. Also, there exists an optimum time to initiate the heating of the adsorbent bed in a day's operation

  17. Investigation on solar desiccant dehumidification process for energy conservation of central air-conditioning systems

    International Nuclear Information System (INIS)

    This paper presents the numerical simulation results of an open cycle liquid desiccant dehumidification system, attempts to obtain the best configurations of the solar assisted air-conditioning system and to validate the feasibility of using a liquid desiccant dehumidification system to handle the latent load and improve the energy efficiency of HVAC systems. Firstly, based on the steady state simulation model of a solar collector/regenerator (C/R) system, the energy performance for using exhaust air to regenerate the weak desiccant solution and heating the solution to a temperature higher than the equilibrium value were tested and discussed for different lengths of the collector/regenerator panels. It was found that the thermodynamic performance was significantly improved and it was possible to shorten the length of the solar C/R without degrading the performance greatly. Secondly, the transient performance of the open cycle liquid desiccant dehumidification system was simulated for the weather conditions of Hong Kong. The energy saving, compared with a conventional vapor compression system, is in the range of 25-50%. The higher the portion of latent load in the total ventilation load, the more the energy saving

  18. Fuzzy logic controller implementation for a solar air-conditioning system

    International Nuclear Information System (INIS)

    The implementation of a variable structure fuzzy logic controller for a solar powered air conditioning system and its advantages are investigated in this paper. Two DC motors are used to drive the generator pump and the feed pump of the solar air-conditioner. Two different control schemes for the DC motors rotational speed adjustment are implemented and tested: the first one is a pure fuzzy controller, its output being the control signal for the DC motor driver. A 7 x 7 fuzzy matrix assigns the controller output with respect to the error value and the derivative of the error. The second scheme is a two-level controller. The lower level is a conventional PID controller, and the higher level is a fuzzy controller acting over the parameters of the low level controller. Step response of the two control loops are presented as experimental results. The contribution of this design is that in the control system, the fuzzy logic is implemented through software in a common, inexpensive, 16-bit microcontroller, which does not have special abilities for fuzzy control

  19. Thermal properties in phase change wallboard room based on air conditioning cold storage

    Institute of Scientific and Technical Information of China (English)

    陈其针; 刘鑫; 牛润萍; 王琳

    2009-01-01

    By comparing the thermal performance parameters of an ordinary wall room with a phase change wall (PCW) room,the effect of phase change wallboard on the fluctuation of temperature in air-conditioning room in summer was studied. And PCW room and an ordinary wall room,which are cooled by air-conditioner,were built up. Differential scanning calorimetry (DSC) was used to test the temperature field and heat flow fluctuation in these rooms. Through analyzing the data tested,it is found that the mean temperature of PCW is lower than that of ordinary wall room by 1-2 ℃,and PCW can lower the heat flow by 4.6 W/m2. Combining phase change material to building envelope can lower the indoor temperature,make the room thermal comfortable,and cut down the turn-on-and-off frequency of air-conditioner,the primary investment and operating costs. It alleviates urgent need of the electric power. Building envelope which contains phase change wallboard can improve the indoor thermal environment,and decrease energy consumption in buildings. Phase change wallboard can make impressive effect on energy efficiency of buildings.

  20. Experimental verification of a condenser with liquid–vapor separation in an air conditioning system

    International Nuclear Information System (INIS)

    Three liquid–vapor separation condensers (LSC) were tested to evaluate their ability to automatically separate the liquid and vapor during condensation. Each was used in a split-type air conditioner to investigate the performance. The performance of the LSC system having the greatest cooling capacity and energy efficiency ratio (EER) was then compared with that of the system having a baseline fin-and-tube condenser for various ambient temperatures from 29 °C to 43 °C. The results showed that both the cooling capacity and EER of the two systems were almost the same at the three standard conditions in the Chinese standard GB/T 7725-2004, with the LSC having just 67% of the heat transfer area of the baseline condenser. In addition, the LSC system was charged with only 80% of the refrigerant in the baseline system. -- Highlights: ► We tested three liquid–vapor separation condensers in an air conditioning system. ► The best system had the most uniform wall temperature and the smallest pressure drop. ► The LSC system performance with only 67% condenser area was as good as the baseline system. ► LSC system operations are compared for various outdoor temperatures

  1. Metal hydride work pair development and its application on automobile air conditioning systems

    Institute of Scientific and Technical Information of China (English)

    QIN Feng; CHEN Jiang-ping; ZHANG Wen-feng; CHEN Zhi-jiu

    2007-01-01

    Aiming at developing exhaust gas driving automobile air conditioning systems, a hydride pair LaNi4.61Mn0.26A10.13/La0.6Y0.4Ni4.8Mn0.2 was developed working at 393~473 K/293~323 K/263~273 K. Property tests showed that both alloys have flat plateau slopes and small hystereses; system theoretical coefficient of performance (COP) is 0.711. Based on this work pair, a function proving automobile metal hydride refrigeration system was constructed. The equivalent thermal conductivities of the activated reaction beds were merely 1.1~1.6 W/(m·K), which had not met practical requirement. Intermittent refrigeration cycles were achieved and the average cooling power was 84.6 W at 423 K/303 K/273 K with COP being 0.26. By altering cycling parameters, experiment data showed that cooling power and system COP increase with the growth of heat source temperature as well as pre-heating and regeneration time while decrease with heat sink temperature increment. This study confirms the feasibility of automobile metal hydride refrigeration systems, while heat transfer properties of reaction beds still need to be improved for better performance.

  2. Experimental study on frosting control of mobile air conditioning system with microchannel evaporator

    International Nuclear Information System (INIS)

    In this paper, a newly developed frost control system is proposed. System bench tests and vehicle test in wind tunnel have been carried out to explore the anti-frosting performance of automotive air conditioning system with microchannel evaporator. The experimental results are compared with the baseline conventional laminated evaporator system. The test results show that the installation position of temperature sensor can dramatically affect the anti-frosting performance. The clutch switching on/off temperature range of the microchannel evaporator is also experimentally studied. The test results show that, with a proper installation position and on/off temperature range, the system COP can be improved, and meanwhile the panel vents' air off temperature can be reduced, and temperature swing can be reduced. - Highlights: → The frost control systems were tested with microchannel and laminated evaporators separately. → The installation position of temperature sensor affects the anti-frosting performance. → Temperature control range affects the anti-frosting performance. → The panel vents' air off temperature and swing can be reduced by proper control parameters. → The system COP can be improved by proper control parameters.

  3. A Closed-Loop Control Strategy for Air Conditioning Loads to Participate in Demand Response

    Directory of Open Access Journals (Sweden)

    Xiaoqing Hu

    2015-08-01

    Full Text Available Thermostatically controlled loads (TCLs, such as air conditioners (ACs, are important demand response resources—they have a certain heat storage capacity. A change in the operating status of an air conditioner in a small range will not noticeably affect the users’ comfort level. Load control of TCLs is considered to be equivalent to a power plant of the same capacity in effect, and it can significantly reduce the system pressure to peak load shift. The thermodynamic model of air conditioning can be used to study the aggregate power of a number of ACs that respond to the step signal of a temperature set point. This paper analyzes the influence of the parameters of each AC in the group to the indoor temperature and the total load, and derives a simplified control model based on the two order linear time invariant transfer function. Then, the stability of the model and designs its Proportional-Integral-Differential (PID controller based on the particle swarm optimization (PSO algorithm is also studied. The case study presented in this paper simulates both scenarios of constant ambient temperature and changing ambient temperature to verify the proposed transfer function model and control strategy can closely track the reference peak load shifting curves. The study also demonstrates minimal changes in the indoor temperature and the users’ comfort level.

  4. Online Air-Conditioning Energy Management under Coalitional Game Framework in Smart Community

    Directory of Open Access Journals (Sweden)

    Wei Fan

    2016-08-01

    Full Text Available Motivated by the potential ability of air conditioning (A/C units in demand response, this paper explores how to utilize A/C units to increase the profit of a smart community. A coalitional game between the households and the load serving entity (LSE in a smart community is studied, where the LSE joins by selling renewable energy to householders and providing an energy saving service to them through an A/C controller. The A/C controller is designed to reduce the amount of electricity purchased from the main grid by controlling A/C units. An online A/C energy management algorithm is developed, based on Lyapunov optimization, that considers both the A/C energy consumption and the thermal comfort level of consumers. In order to quantify the contribution of A/C units, the Shapley value is adopted for distribution of the reward among the participating householders and the LSE, based on their contribution. The simulation result verifies the effectiveness of the proposed coalitional game for a smart community and the algorithm for A/C.

  5. Analyses of an air conditioning system with entropy generation minimization and entransy theory

    Science.gov (United States)

    Yan-Qiu, Wu; Li, Cai; Hong-Juan, Wu

    2016-06-01

    In this paper, based on the generalized heat transfer law, an air conditioning system is analyzed with the entropy generation minimization and the entransy theory. Taking the coefficient of performance (denoted as COP) and heat flow rate Q out which is released into the room as the optimization objectives, we discuss the applicabilities of the entropy generation minimization and entransy theory to the optimizations. Five numerical cases are presented. Combining the numerical results and theoretical analyses, we can conclude that the optimization applicabilities of the two theories are conditional. If Q out is the optimization objective, larger entransy increase rate always leads to larger Q out, while smaller entropy generation rate does not. If we take COP as the optimization objective, neither the entropy generation minimization nor the concept of entransy increase is always applicable. Furthermore, we find that the concept of entransy dissipation is not applicable for the discussed cases. Project supported by the Youth Programs of Chongqing Three Gorges University, China (Grant No. 13QN18).

  6. The performance of a mobile air conditioning system with a water cooled condenser

    Science.gov (United States)

    Di Battista, Davide; Cipollone, Roberto

    2015-11-01

    Vehicle technological evolution lived, in recent years, a strong acceleration due to the increased awareness of environmental issues related to pollutants and climate altering emissions. This resulted in a series of international regulations on automotive sector which put technical challenges that must consider the engine and the vehicle as a global system, in order to improve the overall efficiency of the system. The air conditioning system of the cabin, for instance, is the one of the most important auxiliaries in a vehicle and requires significant powers. Its performances can be significantly improved if it is integrated within the engine cooling circuit, eventually modified with more temperature levels. In this paper, the Authors present a mathematical model of the A/C system, starting from its single components: compressors, condenser, flush valve and evaporator and a comparison between different refrigerant fluid. In particular, it is introduced the opportunity to have an A/C condenser cooled by a water circuit instead of the external air linked to the vehicle speed, as in the actual traditional configuration. The A/C condenser, in fact, could be housed on a low temperature water circuit, reducing the condensing temperature of the refrigeration cycle with a considerable efficiency increase.

  7. Effective Ventilation Parameters and Thermal Comfort Study of Air-conditioned Offices

    Directory of Open Access Journals (Sweden)

    Roonak Daghigh

    2009-01-01

    Full Text Available The study presents objective and subjective studies of thermal comfort levels and ventilation characteristics of two air-conditioned postgraduate study offices. The observations were performed at the offices of Department of Electrical and Electronic Engineering, in University Putra Malaysia. Thermal comfort variables were measured while the students answered a survey on their sensation of the indoor climate. Concurrently, tracer gas analysis, based on concentration decay method, is employed to determine air exchange rate, age of air and air exchange effectiveness. During the air conditioner is working, the study offices had not conditions within the comfort zone, of ASHRAE standard 55 causing occupants to report cold thermal sensations and the objective data analysis showed that the offices were uncomfortable. The thermal neutralities were significantly higher that proposed by ASHRAE Standard 55:1992. The monitored air exchange rates are indicated that the provisions of outside air for ventilation based on design occupancy are adequate for these two study offices. In addition, questionnaires were completed by the students in order to provide a subjective assessment of thermal comfort and indoor air quality. Finally, the outcomes of over 30 surveys for each office responses to the thermal comfort questions are presented and discussed.

  8. Risk Assessment of Heating, Ventilating, and Air-Conditioning Strategies in Low-Load Homes

    Energy Technology Data Exchange (ETDEWEB)

    Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States)

    2016-02-17

    "Modern, energy efficient homes conforming to the Zero Energy Ready Home standard face the challenge of meeting high customer expectations for comfort. Traditional heating, ventilation, and air conditioning (HVAC) sizing and control strategies may be insufficient to adequately condition each zone due to unique load patterns in each room caused by a number of factors. These factors include solar heat gains, occupant-related gains, and gains associated with appliances and electronics. Because of shrinking shell loads, these intermittent factors are having an increasingly significant impact on the thermal load in each zone. Consequently, occupant comfort can be compromised. To evaluate the impact of climate and house geometry, as well as HVAC system and control strategies on comfort conditions, IBACOS analyzed the results of 99 TRNSYS multiple-zone simulations. The results of this analysis indicate that for simple-geometry and single-story plans, a single zone and thermostat can adequately condition the entire house. Demanding house geometry and houses with multiple stories require the consideration of multiple thermostats and multiple zones.

  9. Development of a dynamic model for a DX VAV air conditioning system

    International Nuclear Information System (INIS)

    A direct expansion (DX) variable air volume (VAV) air conditioning (A/C) system consists of a VAV air distribution subsystem and a DX refrigeration plant. This paper reports on the development of a representative and complete dynamic mathematical model for the DX VAV A/C system having a variable speed compressor and pressure independent VAV terminals. The model is component based and takes into account the dynamic behaviors of both the DX refrigeration plant and the VAV air distribution subsystem simultaneously. The dynamic model has been developed based on the principles of mass and energy conservation and using correlations describing the operational performance of some of the system's components, which are either field tested or available from manufacturers. An experimental rig has been set up for the DX VAV A/C system, and experimental work has been conducted to obtain the system's responses to the step change of compressor speed. The dynamic model developed was then validated using the experimental data obtained. Steady state and transient responses for five major operating parameters obtained from both the model and the experiment were compared and found to be in good agreement

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

    Energy Technology Data Exchange (ETDEWEB)

    Kozubal, E.; Herrmann, L.; Deru, M.; Clark, J.; Lowenstein, A.

    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 first 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.

  11. Silicagel-water adsorption cooling prototype system for mobile air conditioning

    Energy Technology Data Exchange (ETDEWEB)

    De Boer, R.; Smeding, S.F.; Mola, S. [ECN Efficiency and Infrastructure, Petten (Netherlands)

    2009-09-15

    A prototype adsorption cooling system was developed for the purpose of on-board test of mobile air conditioning driven by waste heat from the engine. The system was designed, constructed and first tested in the laboratory of ECN. The performance under various static operating conditions was determined in the laboratory. The system can produce 2 kW of chilling power with a COP of 0.4. The prototype was afterward installed in the Fiat Grande Punto demonstration car by CRF. The system was connected to the heating and cooling systems of the car and tested. The performance in the car was comparable to the performance in the lab, indicating that system integration was successful. A waste heat driven adsorption cooling system can be applied for comfort cooling purposes in a car. The amount of waste heat that is freely available in the engine coolant circuit as well as its temperature level is sufficient to drive the adsorption cooling system and to produce enough cold to keep comfortable interior temperatures.

  12. Computerized Simulation of Automotive Air-Conditioning System: A Parametric Study

    Directory of Open Access Journals (Sweden)

    Haslinda Mohamed Kamar

    2013-01-01

    Full Text Available This paper presents results of a parametric study performed on an automotive air-conditioning (AAC system of a passenger car. The goals are to assess the effects of varying the volumetric flow rate of supply air, number of occupants, vehicle speed, and the fractional ventilation air intake (XOA, on the dry-bulb temperature and specific humidity of the air inside the passengers cabin, and on the evaporator coil cooling load of the AAC system. Results of the parametric study show that increasing the supply air flow rate reduces the dry-bulb temperature of the cabin air, increases both the specific humidity of the air and the evaporator coil load. Increasing the number of occupants in the passenger cabin causes the cabin air temperature, specific humidity and the evaporator coil load to increase. Increasing the vehicle speed causes the specific humidity of the cabin air and the evaporator coil cooling load to increase but the dry-bulb temperature of the air is not significantly affected. Increasing the fractional fresh air intake (XOA also increases the cabin air specific humidity and the evaporator coil cooling load.

  13. Analysis of the Impact of Urban Microclimate on Air Conditioning Load Control

    Directory of Open Access Journals (Sweden)

    Hu Xiaoqing

    2016-01-01

    Full Text Available Due to the presence of urban heat island effect (UHIE, high humidity and other urban microclimate, temperature of city central area rises. This causes that the actual air-conditioning energy consumption (ACEC in the urban central area is much higher than that in the suburbs. Load control of air-conditioners (ACs is considered to be equivalent to a power plant of the same capacity, and it can greatly reduce the system pressure to peak load shift. In this paper, a simplified second order transfer function control model of ACs is presented, and its parameters will be influenced by the ambient temperature and urban microclimate. The temperature is obtained by using the temperature inversion algorithm of the heat island effect. Then, the heat index is calculated by combining temperature and humidity. The ambient temperature index of urban central area is modified based on the above microclimate, and the second order linear time invariant model of aggregated ACs is upgraded to the linear time varying model. Furthermore, the consequent parameter changes of the second order transfer function model are studied and the influence of urban microclimate on AC load control is analyzed. The proposed method is verified on numerical examples

  14. Energy-Efficient Supermarket Heating, Ventilation, and Air Conditioning in Humid Climates in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Clark, J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-03-01

    Supermarkets are energy-intensive buildings that consume the greatest amount of electricity per square foot of building of any building type in the United States and represent 5% of total U.S. commercial building primary energy use (EIA 2005). Refrigeration and heating, ventilation, and air-conditioning (HVAC) systems are responsible for a large proportion of supermarkets’ total energy use. These two systems sometimes work together and sometimes compete, but the performance of one system always affects the performance of the other. To better understand these challenges and opportunities, the Commercial Buildings team at the National Renewable Energy Laboratory investigated several of the most promising strategies for providing energy-efficient HVAC for supermarkets and quantified the resulting energy use and costs using detailed simulations. This research effort was conducted on behalf of the U.S. Department of Energy (DOE) Commercial Building Partnerships (CBP) (Baechler et al. 2012; Parrish et al. 2013; Antonopoulos et al. 2014; Hirsch et al. 2014). The goal of CBP was to reduce energy use in the commercial building sector by creating, testing, and validating design concepts on the pathway to net zero energy commercial buildings. Several CBP partners owned or operated buildings containing supermarkets and were interested in optimizing the energy efficiency of supermarket HVAC systems in hot-humid climates. These partners included Walmart, Target, Whole Foods Market, SUPERVALU, and the Defense Commissary Agency.

  15. Energy Savings and Economics of Advanced Control Strategies for Packaged Air-Conditioning Units with Gas Heat

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Weimin; Katipamula, Srinivas; Huang, Yunzhi; Brambley, Michael R.

    2011-12-31

    Pacific Northwest National Laboratory (PNNL) with funding from the U.S. Department of Energy's Building Technologies Program (BTP) evaluated a number of control strategies that can be implemented in a controller, to improve the operational efficiency of the packaged air conditioning units. The two primary objectives of this research project are: (1) determine the magnitude of energy savings achievable by retrofitting existing packaged air conditioning units with advanced control strategies not ordinarily used for packaged units and (2) estimating what the installed cost of a replacement control with the desired features should be in various regions of the U.S. This document reports results of the study.

  16. Heat recovery in air conditioning systems in frost-free season with using adiabatic cooling. Capacities overview

    Directory of Open Access Journals (Sweden)

    S.V. Chuduk

    2011-01-01

    Full Text Available In article the review of the information on possibilities of use of recuperators of heat is presented for the warm period of year for air-conditioning system. Aim of heat exchanger work in frost-free season is indirect cooling of incoming air before its input into maintainable premises. It is possible if exhaust air is cooled before its input into heat exchanger . In the article the operational principle of air conditioning system with using of adiabatic air cooling is considered. The data concerned system functioning depending on parameters of microclimate in maintainable premises are given.

  17. Lorentz and CPT violation in QED revisited: a missing analysis

    International Nuclear Information System (INIS)

    Full text. The Quantum Electrodynamics (QED) with violation of Lorentz and CPT symmetries (called extended QED) has been intensively studied in the last years. It has been frequently asked in the literature that a Chern- Simons-like term is induced by radiative corrections arising from a Lorentz- and CPT-violating term in the fermionic sector. Most of the papers were only devoted to discuss the gauge invariance of the model, putting aside the Lorentz invariance. Here, we also give attention to the discussion of the broken Lorentz symmetry arising from the axial coupling of charged fermions to a constant vector bμ. To the best of our knowledge, the symmetry breaking of rigid Lorentz invariance by bμ has not been investigated in details. In switching on the radiative corrections, it is a non-trivial task to study the effects of such a symmetry breaking. Alternatively, one can ask how the corresponding Ward identity that characterizes the Lorentz breaking behaves at the quantum level. Our aim is to show that, to the contrary of the claims found in the literature, radiative corrections arising from the axial coupling of charged fermions to a constant vector bμ do not induce a Lorentz- and CPT-violating Chern-Simons-like term. We investigate the broken of the Lorentz symmetry in the extended QED by a CPT violating interaction term in the framework of algebraic renormalization - a regularization-independent method, and we show, to all orders in perturbation theory, that a CPT-odd and Lorentz violating Chern-Simons-like term, definitively, are not radiatively induced by the axial coupling of charged fermions to a constant vector bμ. (author)

  18. On radiation reaction and the Abraham-Lorentz-Dirac equation

    CERN Document Server

    de Oca, Alejandro Cabo Montes

    2013-01-01

    It is underlined that the Lienard-Wiechert solutions indicate that after the external force is instantly removed from a small charged particle, the field in its close neighborhood becomes a Lorentz boosted Coulomb field. It suggests that the force of the self-field on the particle should instantaneously vanish after a sudden removal of the external force. A minimal modification of Abraham-Lorentz-Dirac equation is searched seeking to implement this property. A term assuring this behavior is added to the equation by maintaining Lorentz covariance and vanishing scalar product with the four-velocity. The simple Dirac constant force example does not show runaway acceleration.

  19. The Impact of Lorentz Violation on the Klein Tunneling Effect

    CERN Document Server

    Xiao, Zhi

    2016-01-01

    We discuss the impact of a tiny Lorentz-violating $b^\\mu$ term on the one dimensional motion of a Dirac particle scattering on a rectangular barrier. We assume the experiment is performed in a particular inertial frame, where the components of $b^\\mu$ are assumed constants. The results show that Lorentz-violation modification to the transmission rate depends on the observer Lorentz nature of $b^\\mu$. For a spacelike or lightlike $b^\\mu$ the induced resonant frequency shift depends on the polarization, while for timelike $b^\\mu$ there is essentially no modification.

  20. Generalizations of teleparallel gravity and local Lorentz symmetry

    CERN Document Server

    Sotiriou, Thomas P; Barrow, John D

    2010-01-01

    We analyze the relation between teleparallelism and local Lorentz invariance. We show that generic modifications of the teleparallel equivalent to general relativity will not respect local Lorentz symmetry. We clarify the reasons for this and explain why the situation is different in general relativity. We give a prescription for constructing teleparallel equivalents for known theories. We also explicitly consider a recently proposed class of generalized teleparallel theories, called f(T) theories of gravity, and show why restoring local Lorentz symmetry in such theories cannot lead to sensible dynamics, even if one gives up teleparallelism.