ASHRAE RP-1282 Lighting Heat Gain Distribution in Buildings

Sponsor: ASHRAE

Description: 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 two lighting heat gain parameters, the conditioned space/ceiling plenum split and the radiative/convective split, as input data. However, existing data are limited and may be obsolete due to recent advancements in lighting technologies. The current project addresses the need to provide relevant lighting heat gain parameters for a range of common luminaires. The primary objective of the study is therefore to accurately measure these lighting heat gain parameters under realistic operating conditions in a full-scale experimental room. An additional objective is to provide the experimental results in a format that can be readily applied to the ASHRAE cooling load procedures.

Shortwave and longwave radiation leaving the luminaire towards the room are measured with a net radiometer on a 5 degrees-of-freedom traversing rig. A schematic, photos of the experimental apparatus, and a few images showing sample results are shown below.

Keywords: cooling load calculation, lighting, heat gains, radiation, convection

Experimental Configuration

Net Radiometer

Radiometer Traversing Fixture

Radiative Heat Flux Distributions for Recessed Fluorescent Luminaries