On The Relationship between the Radiant Time Series and Transfer Function Methods for Design Cooling Load Calculations

Abstract

In practice, design cooling load calculations are based on steady periodic inputs, but historically cooling load procedures have not taken advantage of this fact. The generalized response factors, conduction transfer functions and room transfer functions currently used in cooling load methods impose an unnecessary computational burden on the procedure. This paper discusses the steady periodic nature of the cooling load calculation and develops the steady periodic conduction and thermal zone response factors used in the new Radiant Time Series Method (RTSM) that was introduced by Spitler et al. (1997). The periodic response factors used in the RTSM are compared to the aperiodic response factors used in the Transfer Function Method (TFM) described by McQuiston and Spitler (1992). Periodic response factors simplify the computational procedure and provide a means of comparing zone and surface types.