2005 Volume 22 Issue 3 Pages 249-257
In order to measure cooling capacity of unit coolers, a few methods have been practically used. But all of them have serious defects that worsen measuring accuracy. Authors propose a novel method for measuring cooling capacity, which has distinct superiorities in high accuracy and brief measuring time. The method employs a short duct on which test cooler and electric heater are installed. The duct is thermally insulated and it has a fan to make air flow inside of the duct. The cooling capacity can be measured by reading electric power meter applied to the heater, under the condition that the temperature at the inlet and the outlet of the duct are equal. A test apparatus that realizes the proposed method is developed to make experiments for validating its feasibility. Preliminary tests disclose that there is fatal temperature deviation in a cross section at the outlet of the duct caused by configuration of heater unit, which spoils the measuring accuracy. Then, a specially designed air mixer is applied to the duct, which successfully suppresses the temperature deviation. Through the tests under various conditions, averaged measuring accuracy is obtained as about 2%, which proves the proposed method can be successfully applied.
