EFFECT OF AIRFLOW AND HEAT INPUT RATES ON DUCT EFFICIENCY.

ANDREWS,J.W.

Brookhaven National Laboratory

关键词: Buildings;    Flow Rate;    Algorithms;    Forecasting;    Design;   

DOI  :  10.2172/812518
RP-ID  :  BNL--71330-2003-IR
RP-ID  :  AC02-98CH10886
RP-ID  :  812518

美国|英语

来源: UNT Digital Library

【 摘 要 】

Reducing the airflow and heat input rates of a furnace that is connected to a duct system in thermal contact with unconditioned spaces can significantly reduce thermal distribution efficiency. This is a straightforward theoretical calculation based on the increased residence time of the air in the duct at the lower flow rate, which results in greater conduction losses. Experimental tests in an instrumented residential-size duct system have confirmed this prediction. Results are compared with the heat-loss algorithm in ASHRAE Standid 152P. The paper concludes with a discussion of possible remedies for this loss of efficiency in existing systems and optional design strategies in new construction.