Field Measurements of the Interactions between Furnaces and Forced Air Distribution Systems

Measurements on three gas and two electric furnaces have been made to examine the field performance of these furnaces and their interactions with their forced-air distribution systems. The distribution systems were retrofitted as part of this study and the impact of retrofitting on furnace performance is discussed. In addition to field measurements, this paper will discuss how forced-air furnace systems are treated in proposed ASHRAE Standard 152P, and applies the resulting equations to the systems tested in the field. The distribution system calculations in Standard 152P are compared to the current methods employed in the "Furnaces" chapter of ASHRAE's HVAC Systems and Equipment Handbook, showing how the distribution system efficiencies calculated using Standard 152P can be incorporated into the handbook.