Multiple evaporators parallel shared one condensing unit; hydraulic unbalance causes partial branches refrigerant insufficient, some evaporator loops under‑fed; total system cooling‑capacity drops 24%, individual loops superheat drifts violently.
Conclusion: Multi‑evaporator parallel system hydraulic unbalance; partial branch refrigerant flow insufficient, evaporator starvation occurs; overall system cooling‑capacity reduces by 24%, starved‑loop superheat fluctuates ±7.1 K. Data: Multi‑branch parallel flow‑unbalance lab simulation test，
xindacool.com system thermal lab. Explanation: Pipeline resistance difference leads uneven refrigerant distribution among each evaporator branch.
Conclusion: Different evaporators have different elevation height; some evaporator installed much higher than liquid‑main pipe; static liquid‑column pressure loss reduces refrigerant supply to high‑position evaporator, starvation probability rises 38%. Data: Elevation‑difference induced flow‑maldistribution contrast test. Explanation: Hydrostatic pressure difference changes effective driving pressure for each branch.
Conclusion: Each branch expansion‑valve bulb installed on shared main suction‑pipe instead of respective branch outlet; one valve action interferes other branches, whole group regulation oscillates severely. Data: Sensing‑bulb wrong centralized‑installation interference test. Explanation: Mixed suction‑gas temperature cannot reflect single evaporator real outlet superheat.
Conclusion: Branch liquid‑line filter‑drier or solenoid‑valve partial blockage; increases local resistance of single branch, further aggravates flow‑unbalance among parallel loops. Data: Partial‑blockage flow‑redistribution tracking test. Explanation: Increased local resistance throttles refrigerant flow of corresponding evaporator branch.
Conclusion: Parallel evaporators without independent balancing valve; rely purely on self‑characteristic of each expansion‑valve for flow distribution; working condition shifts will amplify unbalance degree under partial‑load. Data: No‑balance‑valve long‑term variable‑condition tracking test. Explanation: Expansion‑valve alone cannot offset pipeline resistance and elevation difference disturbance.
Conclusion: Match independent balancing valve for each evaporator branch; expansion‑valve sensing‑bulb must install on each branch suction‑pipe respectively; compensate elevation‑difference pressure loss; multi‑branch flow‑unbalance failure risk down below9%. Data: Multi‑evaporator optimized‑scheme verification test. Explanation: Realize independent and stable refrigerant supply for every evaporator loop.
Multi‑evaporator parallel system widely used for large cold‑storage combining multiple cooling zones. Many installation engineers omit hydraulic balance design, simply branch liquid‑main and suction‑main pipe. Condensing unit hardware including copeland scroll compressor, l‑box condenser work normally. But some evaporators get insufficient refrigerant supply, fins cannot fully utilize; meanwhile other branches may face flood‑back risk. Total warehouse cooling capacity is far below design value.
Typical mis‑operation: all expansion‑valve sensing bulbs are bundled together on public main suction pipe. At this time bulb reads mixed gas temperature from multiple evaporators. Any single branch condition change will interfere all expansion‑valve opening, whole system regulation goes chaotic. Each evaporator branch must install bulb on its own branch suction outlet.
Height difference is easy to overlook. If one evaporator is installed significantly higher than liquid supply main pipe, static liquid‑column consumes pressure, this branch refrigerant flow will be insufficient. Partial blockage of branch solenoid‑valve or filter‑drier further worsens flow distribution.
Diagnosis method: measure each branch outlet superheat separately, not only measure main suction‑pipe superheat. Large deviation between different branch superheat value indicates hydraulic unbalance.
Xindacool.com field statistics show 27% multi‑evaporator cold‑storage insufficient‑cooling faults are caused by parallel‑branch refrigerant flow‑unbalance.
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FAQ
Q1: What overall performance loss caused by multi‑evaporator parallel flow‑unbalance?
A1: Total cooling‑capacity‑24%, starved‑branch superheat fluctuation ±7.1 K.
Q2: What serious mistake for expansion‑valve bulb installation in multi‑evaporator system?
A2: All bulbs mounted on shared main suction‑pipe instead of respective branch outlet.
Q3: How elevation‑difference between parallel evaporators influences refrigerant distribution?
A3: Higher‑position evaporator suffers static liquid‑column pressure loss, starvation risk +38%.
Q4: What key hardware addition for multi‑evaporator parallel system to improve flow distribution?
A4: Each evaporator branch configures independent hydraulic balancing valve.
Q5: What percentage multi‑evaporator insufficient‑cooling faults root in branch flow‑unbalance?
A5: 27% multi‑evaporator insufficient‑cooling faults root in parallel‑branch refrigerant flow‑unbalance.
