Practical thermal design of run-around air-to-air heat recovery system

Abstract

Representing the majority of the run-around heat recovery system, this study proposes a straight-forward explicit thermal design procedure. The exhaust and supply air flow rates, their temperature conditions, and their allowable pressure drops through the coils are commonly given as the most practical design conditions in a run-around heat recovery system. Based on the allowable air pressure drop, the design starts with a minimum number of rows and proceeds until all specifications have been met. Hence the smallest possible coil can be obtained by this approach. With some further practical considerations, a final adjustment may lead to the least expensive and most efficient design. Currently, part of this design procedure is being employed in the heat transfer and heat recovery industry.