EXPERIMENTAL ASSESMENT OF REFRIGERATION SYSTEM CHARACTERISTICS WITH SCROLL COMPRESSOR

In this study, characteristics of a chiller system are investigated. The experimental setup consist of an air cooled condenser, a liquid type shell-tube evaporator, and a scroll compressor. Compressor speed is changed between 30-60 Hz via PWM type frequency inverter. Mass flow rate of the refrigerant R134a is controlled by an electronic expansion valve (EEV) and a thermostatic expansion valve (TXV) in the system. The cooling capacity of the chiller system is about 3 kW. For determining the performance characteristics of the system eight parameters are considered. These are the EEV opening, superheating, subcooling, evaporation/condensing temperatures, and refrigerant flow rate. It is found that the COP decreased to its half and cooling capacity increased 37% by increasing the frequency from 30 Hz to 60 Hz. According to analysis, superheating changing affects various parameters in the system and also it is important to monitor this parameters.