Lighting Heat Gain Parameters: Experimental Method (RP-1282)

Abstract

The energy dissipated by lights is a significant contributor to the space heat gain and the space cooling load in many commercial buildings. To account for the heat gain due to lights, both of ASHRAE's new cooling load calculation procedures require the conditioned space/ceiling plenum split and the radiative/convective split as input data. This paper addresses the need to experimentally determine the lighting heat gain parameters for a range of common luminaires under realistic operating conditions. The paper presents both the measurement procedures and the computational procedures required to obtain derived results. The paper also discusses the uncertainty analysis and the accuracy of experimental results and compares different techniques that can be used to obtain the lighting heat gain parameters. Estimated uncertainties in the conditioned space, the ceiling plenum, and the convective fractions are relatively high. These uncertainties vary between ±0.06 and ±0.19. Estimated uncertainties in the shortwave and the longwave radiative fractions are relatively low, varying between ±0.01 and ±0.08 but mostly less than ±0.03. A companion paper presents experimental results along with their estimated uncertainties, discusses the effects of various parameters on the measured results, and provides guidelines for the application of the experimental results.