Pengaruh Penggunaan LSHX pada Kinerja Mesin Refrigerasi pada berbagai Temperatur Evaporasi

Abstract

Liquid-to-suction heat exchanger (LSHX) has been used for air conditioning and refrigeration machines over years. It was aimed to increase the cooling capacity and coefficient of performance. In this paper, the influence of LSHX utilization on a refrigerating machine with refrigerant R404a was investigated. The tests were focused on the heat exchanger effectiveness under various evaporating temperature. To vary the evaporating temperature, a valve was installed on the inlet side of thermostatic expansion valve. By varying the openings of this valve, the pressure of suction line could be varied from 30 psi to 50 psi, resulting in the evaporating temperatures from -24°C to -10°C. With the LSHX, the liquid refrigerant temperature could be lowered 4°C to 8°C. The reduction of the temperature improves the capacity and coefficient to performance up to 16%. Based on the experiment, the effectiveness of LSHX ranges from 0.18 to 0.25. The lower the evaporating temperature, the higher the effectiveness of LSHX. However, sub-cooling and superheating should be limited to a certain value in order to control the compressor within its safe operating conditions.