Comparison of An Electronic and Thermostatic Expansion Valves in Refrigerant Control of Evaporator

摘要

Use of an electronic control expansion valve (EEV) has become more and more popular, taking the place of a formerly used thermostatic expansion valve (TEV), in controlling evaporator superheat of the refrigeration system installed to fishing boats, including tuna purseseiners.Refrigeration efficiency was compared between EEV and TEV taking advantage of T/S Nagasaki-maru which has a refrigeration system equipped with both EEV and TEV to be used alternately. The efficiency of EEV being operated under the best combination of the control parameters foundby us was compared with that of TEV. Repeated experiments revealed thatby using EEV the cooling time before reaching the desired refrigeration temperature can be mach shortened (4h-35m by TEV vs 3h-28m by EEV) and the state of operation becomes more stable. Thus, the result of our experiments shows that the efficiency of the refrigeration equipment with TEV can be economically improved by just changing TEV for EEV.