الفهرس 
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Abstract
The objective of this study is to present a simulation model of reciprocating vapor-compression refrigeration chillers using R-134a as a refrigerant at steady-state conditions. The study is primarily concerned with both sizing and thermal performance of air-cooled chillers. Energy and cost comparisons between air-cooled and water-cooled chillers are also undertaken The different components of this model are condenser, evaporator, compressor and expansion valve. The study presents a generalized design at different cooling loads for a finned-tube air-cooled condenser and shell-and-tube evaporator, which is based on mathematical equations for heat transfer and pressure drop. The condenser design is accomplished numerically and gives satisfactory results compared with those listed in commercial catalog data. The evaporator design is solved according to Y.EMA standards and its recommendations. The generalized design for condenser and evaporator are presented in graphical charts giving the optimum sizes corresponding to cooling load and minimum cost. In the compressor model, the compressor input is determined according to the isentropic analysis taking into account the compression efficiency. The expansion is considered as constant enthalpy in the expansion valve.
The purpose of the simulation model can be discussed into twofold
a) To investigate the effect of change of ambient air temperature and the conditioned space load, during operation of chiller, on chiller performance characteristics, including evaporator capacity, compressor shaft power, refrigerant mass flow rate, evaporating and condensing temperature, and cooling coefficient of performance (COP).
b) To investigate also an adequate control by stopping number of fans or changing fan speed and operating or stopping number of compressors or unloading number of compressors cylinders during overload and part-load operations.
The cost of each component in chiller cycle is based on Egyptian pound value, the cost was accomplished in (August 2000), and after this period, the value of Egyptian pound had been decreased against the value of American dollar.