3442 -- Test of Condensate Subcooling Coils for Air Conditioners PDF

A two-ton compact air conditioner was developed for a sheltered environmental control application. The cooling capacity requirement was 2 tons at an outdoor ambient temperature of 110 deg F (43 deg C) and an indoor dry-bulb temperature of 80 deg F (27 deg C), a wet-bulb (WB) temperature of 67 deg F (19 deg C), and a sensible heat ratio of 0.8. A serpentine coil was installed at the bottom of the drain pan to take advantage of cool condensate for improved cooling capacity. The coil was arranged in the prototype unit such that three different condensate reuse options can be tested by either connecting the coil to the condenser exit or compressor inlet (desuperheating) or by cutting the coil completely out of the system operation. The added coil did increase the cooling capacity by 5.5% to 8.8% and lower the discharge pressure by 5 to 10 psi (35 to 70kPa) at a 95 deg F (35 deg C) outdoor temperature compared with the test data when the coil was not used at all. The coil worked best when it was used as a subcooling coil for refrigerant liquid. Presents some quantitative test results for the performance of the unit when the additional coil was used as a subcooling coil or not used at all.

KEYWORDS: condensate, subcooling, coils, compressors, unit air conditioners, testing, performance, cooler batteries, air conditioning