Optimization of a solar driven adsorption refrigeration system

Optimization of a solar driven adsorption refrigeration system

13 Space heating and cooling performance, whereas the dehumidifier has a minor effect. Also, the simulated system was capable of providing a cool s...

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13 Space

heating

and cooling

performance, whereas the dehumidifier has a minor effect. Also, the simulated system was capable of providing a cool supply of air at acceptable comfort conditions for various summer days in Baghdad. 02/01111 Classic wall gas boiler regulation and a new thermostat using fuuy logic - improvements achieved with a fuzzy thermostat Miriel, .I. and Fermanel, F. Applied Energy, 2001, 68, (3), 229-247. The present paper deals with the improved performances and thermal comfort of individual forced hot water heating systems equipped with a gas fired wall boiler, for homes. The problems of such systems are due to the high power of the burner which causes cyclic running. Furthermore, the installation of a room thermostat is imposed by the French thermal regulations. Developed independently from the boiler, the thermostat does not fit its environment. The manual aquastat set point adjustment at the boiler can lead to a set point conflicting with that of the thermostat. Hence, the authors have developed a new room thermostat, based on a fuzzy logic function, which takes into account the system reactions. This thermostat assimilates the characteristics of the different parts of the system: boiler, heaters, building, climate, etc. The new thermostat was tested in simulation and good results were obtained. Then, it was validated experimentally.

from water evaporation at the clothing level for the immediate body environment, and also for the outside air cooling. The enormous need of water for a natural air conditioning was one reason for the aqueduct built by the Romans.

02/01116 Multi-parameter building thermal analysis using the lattice method for global optimisation Saporito, A. et ul. Energy und Buildings, 2001, 33, 267-274. The energy performance in buildings is a complex function of the building form and structure, heating system, occupancy pattern, operating schedules, and external climatic conditions. Computer simulations can help understand the dynamic interactions of these parameters. However, to carry out a multi-parameter analysis for the optimisation of the building energy performance, it is necessary to reduce the large number of tests resulting from all possible parameter combinations. In this paper, the lattice method for global optimization (LMGO) for reducing the number of tests was used. A multi-parameter study was performed to investigate the heating energy use in office buildings using the thermal simulation code APACHE (IES-FACET). From the results of the sensitivity analysis it was possible to estimate the relative importance of various energy saving features.

Numerical studies of airflows induced by mechanical ventilation and air-conditioning (WAC) systems

02/01117

Development of parameter based fault detection and diagnosis technique for energy efficient building management system

02/01112

Kumar, S. er al. Energy Conversion md Monogemen!, 2001,42, (7), 833854. This paper presents a complete methodology for detection and diagnosis of faults in variable air volume air handling units. Three cases are considered: (a) an off-line fault detection technique for existing buildings, (b) an automatic on-line fault detection technique for integration in building management systems (BMSs) of upcoming not very complex buildings and (c) an automatic on-line fault detection as well as diagnosis technique for BMSs of upcoming complex automated buildings. The method is based upon the auto regressive exogenous model and recursive parameter estimation algorithm. The proposed model and methodology have been tested by using several days of normal real time operational data and validated on data obtained by introducing faults artificially under normal operating conditions. It is concluded that the method is robust and can detect faults in dampers, sensors and PID control.

02/01113 DG XII programme: retrofitting of museums for antiquities in the Mediterranean countries

Tombazis, A.N. and Preuss, S.A. Energy and Buildings, 2001, 33, 251255. This project has studied a selection of 16 typical museums for antiquities in five Mediterranean countries and was partly funded by the JOULE III of the European Commission DC XII. Through an elaborate analysis and complete refurbishment of the Archaeological Museum of Delphi, the programme has provided an example for an innovative mmeum design based on present-day know-how.

02/01114 Double-lift absorption refrigeration cycles driven by low-temperature heat sources using organic fluid mixtures as working pairs Medrano, M. er al. Applied Energy, 2001, 68, (2), 173-185. At present, much interest is being shown in absorption refrigeration cycles driven by low temperature heat sources, such as solar energy or low-grade waste-heat. Double-lift absorption cycles working with ammonia-water have been recommended for refrigeration applications which require cold at 10°C and which are activated by waste heat between 70 and 100°C. This paper discusses the potential of the organic fluid mixtures trifluoroethanol (TFE)-tetraethylenglycol dimethylether (TEGDME or E181) and methanol-TEGDME as working pairs in series flow and vapour exchange double-life absorption cycles. The ammonia-water mixture was used for comparison purposes. The results show that the performances of these cycles improve significantly when they have the above mentioned organic fluid mixtures as working pairs. For example, the coefficient of performance of the vapour exchange cycle working with TFE-TEGDME is 15% higher than with ammonia-water. In this study, a modular software package is used, developed for the thermodynamic properties and cycles simulation of absorption systems.

02/01115

Human thermal comfort at Nimes in summer heat

Berger, X. Energy md Buildings, 2001, 33, 283-287. Various aspects of comfort are analysed through a set of questions asked of 90 urban pedestrians. Answers show the contribution that clothes, time adaptation and other non-thermal effects make in lowering the skin wetness and the perception of warmth. A shift exists between theory (established with subjects in climatic chambers) and statements. Searching for a comfortable feeling in this city, the hottest in France (Metropolis), but without any river, lake or seaside, results 136

Fuel and Energy Abstracts

March 2002

Chow, W.K. Applied Energy, 2001, 68, (2), 135-159. Indoor air flows induced by mechanical ventilation and air-conditioning (MVAC) systems are simulated by the technique of computational fluid dynamics (CFD). Examples are taken to illustrate the capability of the technique. These include the evaluation of basic ventilation system designs, ventilation systems in an enclosed car-park, spot cooling system, air-conditioning system with chilled ceiling, cold air distribution system, effect of casual heat gain on the air diffuser induced air flow and the underfloor air supply system. Evaluation of the performances of the mechanical systems in those buildings are performed. Physical experiments in air-conditioned spaces reported by Sakamoto and Matsuo; and by Murakami and Kato are also simulated to assess the predicted results. 02/01116 On the optimum channel sizing for HVAC systems Soylemez, M.S. Energy Conversion md Munugemen/, 2001,42, (7), 791798. Economic channel sizing for HVAC system applications is studied in the present work. Original formulas are developed and presented after the optimization study. Economically optimum channel sizes are determined for round and rectangular ducts. The PI-P2 method is used in this study, including the effects of all economic parameters.

02/01119 Optimization of a solar driven adsorption refrigeration system

Alam, K.C.A. el crl. Energy Conversion und Management, 2001, 42, (6), 741-753. This paper deals with the thermodynamic optimization of a solar driven adsorption refrigeration system. An externally irreversible but internally endoreversible model has been employed to analyse the optimum conditions for which the maximum refrigeration effect can be achieved. It is seen that a chiller attains its highest capacity if the thermal conductances of the heat exchangers are distributed properly. It is also seen that half of the total thermal conductances are allocated between the condenser and adsorber heat exchangers that release heat to the external ambient. The coefficient of performance (COP) for the optimum conditions is also presented. It is observed that the COP,,, increases in parallel with the dimensionless collector stagnation of the required temperature Tag, as well as with the increase refrigeration space temperature, rr, while the COP,, t decreases as the ratio of collector size to the cumulative size o P all four heat exchangers, B, increases.

Performance analysis on a mutti-type inverter air conditioner

02/01120

Park, Y.C. et nl. Energy Conversion und Munagement, 2001, 42, (13), 1607-1621. An analysis was conducted for a multi-type inverter air conditioner with a linear electronic valve as the expansion device and a variable speed compressor. The system performance was analysed with variations of operating frequency of the compressor, cooling load imposed on the system and cooling load fraction (i.e. load ratio) between rooms in which is installed an evaporator. The optimum opening of the electric expansion valve (EEV) was calculated when the compressor operating frequency was specified at a given cooling load. As compressor operating frequency increased with cooling load increment, the EEV should have adjusted to get wide openings to get an optimum COP of the system. While total cooling load of the system was constant, the cooling load fraction changed due to the cooling load differences between each room in the multi-type air conditioning system with a number of evaporators and EEVs. The