reciprocating compressor, efficiency, optimization, analtyical model
Most compressors in air conditioning (AC) units are designed by trying to minimize the initial cost. The effect of these designs on the operating cost of the system, for the life of the component, is often neglected. This project provides a solution to this issue. The objective of this project is to create an analytical model that simulates an actual AC unit and then use it to arrive at the optimized design variables based on the lowest total life-cycle cost. Performance of a compressor is affected by several factors including compressor speed, suction and discharge pressures, and component geometry and valve efficiencies. The effect of these factors on the compressor performance in terms of volumetric and isentropic efficiencies is modelled for a reciprocating compressor. Experimental data is collected from an AC unit to verify and validate the analytical model at different ambient conditions. Heat balances between the refrigerant and air side of the heat exchangers were used to confirm the accuracy of the instrumentation. A parameter optimization was conducted on the empirical coefficients used in the analytical model with an objective function of minimizing the RMS error between the model and experimental data. With this the heat balances were achieved within a 10% error over the entire range of operating conditions. This validated model can be used to optimize the compressor efficiencies to obtain the lowest total life-cycle cost for different working environments.