Numerical Modeling of Lighting/HVAC Interaction in Enclosures Part I: Light and Heat Transfer in a Room

Abstract

A numerical model based on heat transfer equations was developed for the dynamic simulation of a room with lamps in luminaires as the only power source. The model was used to consider heat transfer by conduction, convection and radiation between surfaces in the luminaire, the plenum space and the room space. Also, it was used to calculate temperatures, cooling loads, and lighting levels at each time step. It was designed to be flexible so that different room configurations could be simulated. The main differences between this model and previous models in the literature are that, firstly, this model does not assume that some nodes are massless; secondly, it calculates illuminance on room surfaces; and thirdly, a fluorescent lamp positive column model can be incorporated at a later stage for improved simulation of lighting levels for a room; these differences represent an improvement on similar existing models. The present model was validated, using the experimental results reported by Treado and Bean (1988, 1992), and using further experimental measurements obtained from a laboratory-constructed test cell. Further validation was conducted using the numerical test cell developed by Sowell (1990). Results predicted by the model agreed well with experimental results from both the NIST test cell and the laboratory test cell. The incorporation of a fluorescent lamp positive column model is presented in Part II.