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Abstract Controlling the enthalpy is an important factor in maintaining comfort and healthy conditions within a conditioned space because controlling enthalpy means conjugate control of the space sensible and latent load. Humidity control is difficult especially in humid climates, where there is a high latent load, such as an indoor pools, supermarkets, and auditoriums. Without proper dehumidification, these areas become uncomfortable, unhealthy, and corrosive Many methods are suggested to control the enthalpy. Adjusting Fan and Compressor Speeds is one of those methods. The present work examines first the effect of changing compressor and fan speeds on the conditions inside the space as well as the air sensible and latent load to decide which one of the two should control temperature and which should control humidity. A computer program has been developed for a typical simulated system performance data. This program has been used to compare the space conditions and the set-points during load variations. Also, the responses of the suggested air conditioning system with variation of space loads are studied. An experimental setup has been constructed in the Air Conditioning Laboratory (Faculty of Engineering, Alexandria University) to obtain reliable experimental measurements for studying the behavior of the air conditioner when working with a variable speed compressor and a variable speed fan and verify. the results of the mathematical model. The mathematical model has been validated using the experimental resultsThe effect of changing the room sensible heat ratio ranged from 1 to 0.6 on the compressor and fan speeds has been studied. Moreover, its effect on the total power consumed and the ratio between room total heat and air mass flow rate (RTH/mOa) have also been studied. Also, the effect of compressor and fan speed ratios on room loads ratio has also been studied. Finally, a new approach system is introduced and compared with those of a nominal air conditioning system and a step control system. Figures which can be used to determine the compatible operating speed for the compressor and the evaporator fan and predict the percentage of energy saving by knowing RTH/moa and room sensible heat ratio (RSHR), are also drawn. |