“…In the refrigerating engineering field, Ma & Wang (2011) developed bypass check valve to enhance the overall system performance; Choi, B. Kim, Kang, & K. Kim (2011), and J. Kim, Choi, & K. Kim (2015) applied the bypass for defrosting in the heat pump; Tuo & Hrnjak (2012) showed that flash gas bypass method could improve refrigerant distribution and reduce pressure drop on refrigerant side in the mobile air conditioning system; Byun, Lee, & Jeon (2008) discovered that the hot gas bypass method was useful for retarding the formation and growth of frost at the outdoor coil and for improving the performance of the air source heat pump; Tso, Wong, Jolly, & Ng (2001) conducted simulation studies using a mathematical model to compare the performance of the hot-gas by-pass control and the suction modulation control in refrigerated shipping containers, their results showed that the suction modulation control strategy was the more energy efficient of the two; Elbel & Hrnjak (2004) found that the performance of transcritical R744 systems with direct expansion could be significantly improved by implementing a flash gas bypass; it was demonstrated by Wang, Han, Shi, & Li (2012) that suction gas bypass was an effective regulating method of scroll compressor, and it could reduce the inner compression loss under over compression conditions and largely decrease the heating/cooling capacity of the refrigeration system; used flash gas bypass for vapor-liquid separation in vapor compression systems; Huang, Li, & Yuan (2009) suggested that the hot-gas bypass defrosting could overcome the main disadvantages of the reverse-cycle defrosting method; Ding, Zhang, & Lu (2004) proved bypass two-circuit cycle freezers with one compressor were more efficient than two-evaporator in series cycle freezers in reducing the greenhouse gas emissions.…”