The condensing temperature of the refrigeration unit is too high
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There are two refrigeration units of the same model. Unit A has a condensation temperature of around 37 degrees and a current consumption of 67A, while Unit B has a condensation temperature of around 40 degrees and a current consumption of 76A. The load on both units is the same. Upon inspection of Unit B’s condenser, no issues were found; the temperature difference between the inlet and outlet water of the condensers in both units is roughly the same. If the economizer of Unit B is turned off, the current drops by about 10A immediately, and the condensation temperature also decreases; however, the energy level increases, and non-condensable gas is discharged from the top of the condenser. As a result, the condensation temperature and current in Unit B remain high, sometimes approaching the alarm values. The manufacturer also came to check, but still couldn’t find the cause
Unit A uses a mechanical expansion valve, while Unit B uses an electronic expansion valve
The poster listed data such as the suction and exhaust pressures, suction and exhaust temperatures, inlet and outlet water temperatures, as well as the pressure differences across the various components, so that everyone can make an assessment
Based on what you’ve described, it could be a problem with the set value of the electronic expansion valve in unit B, or there might be an issue with the temperature that the expansion valve is trying to track; this could lead to an excessive opening degree of the expansion valve. Of course, there could be other issues as well, but these are the possibilities based on the symptoms you’ve described in your post
Unit A: Absorption pressure 1.34 bar(a), exhaust pressure 14.1 bar(a), exhaust temperature 78 degrees, condensation temperature 36.4 degrees; current 67 A. Circulating water temperature at the inlet and outlet of the condenser: 28.5/33 degrees. Unit B: Absorption pressure 1.34 bar(a), exhaust pressure 15 bar(a); condenser temperature 39.5 degrees, current 74 A. Circulating water temperature: 28.5/33.5 degrees, exhaust temperature 77 degrees. The flow rates of the circulating water in the condensers of Units A and B are fairly similar
The valves in the pipelines of units A and B were replaced before the New Year. The pipelines of these units are quite long, about 300 meters in length; they are Freon direct-cooling units. After the valves were replaced, the system was evacuated to a pressure of -0.06 MPa. Is the vacuum level too low, meaning that the air wasn’t completely removed? However, non-condensable gases have been removed from the highest points of the condenser several times, and during these removal processes, the condensation temperature shown on the unit’s PLC did not change