Evaluations have been made of a possible alternative to the tracer gas test method now being used to measure off-period energy loss of space heating equipment with vent dampers.

This alternative method offers the potential of a direct-measurement method without the need for expensive tracer-gas-type instrumentation. The method uses a controlled flow of gas to a small gas-fueled burner to simulate normal flue or stack temperatures previously measured during a cool-down test. Energy metered through the gas burner during the simulation gives a direct measurement of the thermal energy losses out of the stack. Results in comparison with the tracer gas method of test were lower for off-period energy loss measurements. A trend to better agreement between the two methods was noticeable for test furnaces with greater fuel. input rates. Further development, testing, and evaluation will be required before the sinulation can be considered as an acceptable alternative test method.

Units: Dual