Predicting the Energy Performance Ratings of a Family of Type I CombinationAppliances

摘要

ANSI/ASHRAE Standard 124-1991 specifies the laboratory tests and the calculationprocedure for estimating seasonal and annual performance of combination appliances which are designed to provide both space heating and water heating. A boiler that includes a tankless coil for water heating is covered by those sections in ASHRAE Standard 124 that pertain to Type I combination appliances. In an effort to minimize the test burdens on manufacturers, a computer simulation study was conducted to determine if a subset of a family series of Type I combination appliances could be tested and used to predict the performance of the rest of the appliances in the family. Computer simulation was conducted on a family of five different size boilers with an identical tankless coil to calculate their Combined Annual Efficiency (CAE) as specified in ASHRAE Standard 124. To this end, the Energy Factor (EF) for water heating and the Annual Fuel Utilization Efficiency (AFUE) for space heating were calculated. For the water heating test that was simulated, daily hot water draw volumes of 243.4 liters (64.3 gal.) and 454.2 liters (120 gal.) were used. The results showed that for the five boilers, the AFUE for space heating differed by less than 1 percent.