Measured Effects of Retrofits - A Refrigerant Oil Additive and a Condenser Spray Device - On the Cooling Performance of a Heat Pump

摘要

A 15-year old, 3-ton single package air-to-air heat pumpwas tested in laboratory environmental chamberssimulating indoor and outdoor conditions. Afterdocumenting initial performance, the unit was retrofittedwith a prototype condenser water-spray device andretested. Results at standard AM cooling ratingconditions (95?F outdoor dry bulb and 80167 OF indoordry bulb/wet bulb temperatures) showed the capacityincreased by about 7%, and the electric power demanddropped by about 8%, resulting in a steady-state EERincrease of 17%. Suction and discharge pressures werereduced by 7 and 37 psi, respectively.A refrigerant oil additive formulated to enhancerefrigerant-side heat transfer was added at a dose of oneounce per ton of rated capacity. and the unit was testedfor several days at the same 95?F outdoor conditions andshowed essentially no increase in capacity, and a slight3% increase in steady-state EER. Adding more additivelowered the EER slightly. Suction and dischargepressures were essentially unchanged.Our short-term testing showed that the condenser-spraydevice was effective in increasing the cooling capacityand lowering the electrical demand on an old andrelatively inefficient heat pump, but the refrigerantadditive had little effect on the cooling performance ofour unit Sprayer issues to be resolved include the effectof a sprayer on a new, high-efficiency air conditioner/heatpump, reliable long-term operation, and economics.