Experimental Researches on Zero Superheat in Refrigeration Cycle

In a steam-compression refrigeration cycle, optimum heat exchange efficiency is acquired and compressor liquid hammer can be avoided if “zero superheat” arises at dry-evaporator outlet. Therefore zero superheat control study is of value. since refrigeration cycle will not get stable while it tends to hunt nearby zero superheat, expansion valve-dry evaporator regulation loop have to run at a positive superheat; and no fit theory is able to guide the design on the stability of expansion valve-dry evaporator regulation loop until the cause of refrigeration cycle hunting is found. Flow display experiments reveal the mechanism that refrigeration cycle will hunt next to 0 superheat while vapor/liquid two phase flow alternates at expansion valve exit. on the ground that phases can be told apart by thermal sensing rather than superheat, a specialized sensor has been developed to detect 0 superheat signal which serves as the feedback signal of expansion valve-dry evaporator regulation loop, the experiment results prove that the thermal sensor can afford 0 superheat.