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Energy Efficient Hospitals Air Conditioning Systems  [PDF]
Essam E. Khalil
Open Journal of Energy Efficiency (OJEE) , 2012, DOI: 10.4236/ojee.2012.11001
Abstract: Energy Efficiency and Indoor Air Quality in the healthcare applications and particularly in surgical operating theatres are important features in modernized designs. The various reasons for deviation from obtaining optimum IAQ and energy efficient buildings are listed. The air conditioning systems serving the operating rooms require careful design to minimize the concentration of airborne organisms. Numerical approach is an appropriate tool to be utilized to adequately identify the airflow patterns temperatures and relative humidity distributions and hence energy efficient designs.
Energy Efficient Air Conditioning System Using Geothermal Cooling-Solar Heating in Gujarat, India  [PDF]
Sneha Shahare, T. Harinarayana
Journal of Power and Energy Engineering (JPEE) , 2016, DOI: 10.4236/jpee.2016.41004
Abstract: It is well known that one unit of electrical energy saved is equal to more than two units produced. One way of economizing the power is utilization of energy efficient systems at all locations. In the present study, the air conditioning system is analysed and an innovative way is suggested. We use natural low temperature of shallow sub surface (1 - 3 m) of the earth—geothermal cooling system. It is known that majority of the households and the apartment complexes in India have two tanks for water storage. One is the underground water sump and the other is the overhead water tank. In our study, we use these two water storage systems for space cooling during summer and also for heating during winter. The main aim of our paper is air-conditioning of the space in an economic way to save electricity. It is based on a simple idea of transferring the low temperature from underground water sump to the room in the house using water as a mode of transport. Since India is a tropical country located at low latitude, most of the year, the air temperature is high and demands space cooling. However, for a couple of months during severe winter months (Dec.-Jan.) at Ahmedabad, heating of the space is required. For heating the space, we suggest to use the well-known solar water heater. Effective use of heat exchanger is shown through computation, modelling schemes and lab experiment. We recommend geothermal cooling for 10 months in a year and solar hot water system during 2 months of winter. It is observed that the ambient air temperature of 35°C - 40°C in the room can be brought down to 26°C without much consumption of electricity. In a similar manner, the room temperature at night (13°C) during winter in Ahmedabad can be increased to 27°C through circulation of water from solar water heater in the heat exchanger.
Design and Construction of a Scroll Compressor of an Automobile Air Conditioning System
JA Akpobi, OI Ajayi
Journal of Applied Sciences and Environmental Management , 2007,
Abstract: This work focuses on the design and manufacture of a scroll compressor used in an automobile air conditioning system. A scroll compressor is a positive-displacement machine that compresses air with two interfitting spiral shaped scroll members. This compressor is of semi-hermetic design, and is quiet, reliable and efficient in performance
Autonomous Air Conditioning System  [PDF]
Syed Fazil Bin Farukh,M. Saleem Khan
International Journal of Computer and Electrical Engineering , 2013, DOI: 10.7763/ijcee.2013.v5.755
Abstract: This paper presents an autonomous air conditioning control system using fuzzy time control discrete event model. The system is designed with two inputs: Temperature, humidity and two outputs: fan speed and fan spinning time. Temperature and humidity are controlled by controlling the three valves i.e. cooling valve, heating valve and humidifying valve. System takes feedback from sensors. Fuzzy time control rules are formed and simulated using the MATLAB tool box. The results obtained from the MATLAB simulation are found to be correct according to the design modeling. The work is based on fuzzy time control discrete event model and implementation of design algorithm. this research work will inanes the capability of the existing fuzzy logic control system and discusses the time control issues of digital dynamical control systems.
Development of Fuzzy Logic Control for Vehicle Air Conditioning System
Henry Nasution
TELKOMNIKA , 2008,
Abstract: A vehicle air conditioning system is experimentally investigated. Measurements were taken during the experimental period at a time interval of one minute for a set point temperature of 22, 23 and 24oC with internal heat loads of 0, 1 and 2 kW. The cabin temperature and the speed of the compressor were varied and the performance of the system, energy consumption and energy saving ware analyzed. The main objective of the experimental work is to evaluate the energy saving obtained when the fuzzy logic control (FLC) algorithm, through an inverter, continuously regulates the compressor speed. It demonstrates better control of the compressor operation in terms of energy consumption as compared to the control by using a thermostat imposing On/Off cycles on the compressor at the nominal frequency of 50 Hz. The experimental set-up consists of original components from the air conditioning system of a compact passenger vehicle. The experimental results indicate that the proposed technique can save energy and improve indoor comfort significantly for vehicle air conditioning systems compared to the conventional (On/Off) control technique.
An evaporative and desiccant cooling system for air conditioning in humid climates
Camargo, J. R.;Godoy Jr, E.;Ebinuma, C. D.;
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2005, DOI: 10.1590/S1678-58782005000300005
Abstract: evaporative cooling operates using water and air as working fluids. it consists in water evaporation, through the passage of an air flow, thus decreasing the air temperature. this system has a great potential to provide thermal comfort in places where air humidity is low, being, however, less efficient where air humidity is high. a way to solve this problem is to use dehumidifiers to pre-conditioning the process air. this paper presents a system that can be used in humid climates coupling desiccant dehumidification equipment to evaporative coolers. the paper shows, initially, the main characteristics of the evaporative cooling and of the adsorption dehumidification systems. later on the coupled systems, in which occurs a dehumidification by adsorption in a counter flow rotary heat exchanger following the evaporate cooling of the air in evaporative coolers, are analyzed. the thermodynamic equations of state are also presented. following, this paper analyzes some operation parameters such as: reactivation temperature, r/p relationship (reactivation air flow/ process air flow) and the thermodynamic conditions of the entering air flow. the paper shows the conditions for the best operation point, with regard to thermal comfort conditions and to the energy used in the process. in addition this paper presents an application of the system in different climate characteristics of several tropical and equatorial cities.
An evaporative and desiccant cooling system for air conditioning in humid climates  [cached]
Camargo J. R.,Godoy Jr E.,Ebinuma C. D.
Journal of the Brazilian Society of Mechanical Sciences and Engineering , 2005,
Abstract: Evaporative cooling operates using water and air as working fluids. It consists in water evaporation, through the passage of an air flow, thus decreasing the air temperature. This system has a great potential to provide thermal comfort in places where air humidity is low, being, however, less efficient where air humidity is high. A way to solve this problem is to use dehumidifiers to pre-conditioning the process air. This paper presents a system that can be used in humid climates coupling desiccant dehumidification equipment to evaporative coolers. The paper shows, initially, the main characteristics of the evaporative cooling and of the adsorption dehumidification systems. Later on the coupled systems, in which occurs a dehumidification by adsorption in a counter flow rotary heat exchanger following the evaporate cooling of the air in evaporative coolers, are analyzed. The thermodynamic equations of state are also presented. Following, this paper analyzes some operation parameters such as: reactivation temperature, R/P relationship (reactivation air flow/ process air flow) and the thermodynamic conditions of the entering air flow. The paper shows the conditions for the best operation point, with regard to thermal comfort conditions and to the energy used in the process. In addition this paper presents an application of the system in different climate characteristics of several tropical and equatorial cities.
Simulation technology for refrigeration and air conditioning appliances
Guoliang Ding
Chinese Science Bulletin , 2006, DOI: 10.1007/s11434-006-2072-6
Abstract: 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.
Fungal colonization of air-conditioning systems
Ljaljevi?-Grbi? Milica,Vukojevi? Jelena,Stupar M.
Archives of Biological Sciences , 2008, DOI: 10.2298/abs0802201l
Abstract: 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.
Carbon Emissions from air-Conditioning  [PDF]
Rajesh Kumar
American Journal of Engineering Research , 2013,
Abstract: 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.
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