单项选择题
What is the purpose of sub cooling R-12 in the condenser?（）
A.to increase the system efficiency by sensible heat transfer B.to stop the liquid from flashing C.to reduce the load on the compressor D.to remove latent heat of vaporization and the suction piping transfer
单项选择题 In terms of pressure and temperature in the refrigerant in the compressor, what happens to the primary?（）
单项选择题 The solenoid valve can be typed as a（）
单项选择题 If the compressor runs continually, the cause might be the（）
