The effects of interior emissivity and room layout on forced air space-conditioning power usage

Through computational fluid dynamics studies, this paper analyzes the effects of and interactions between interior surface emissivity, positioning of forced-air supply/return locations, and building “tightness” on space-conditioning power requirements in a simple model room. Each is shown to be important, but all are highly interdependent. In well-sealed rooms, layout is shown to be largely unimportant and extremely low-emissivity (ε=0.1) a slight (2-5%) benefit. With high infiltration or external ventilation requirements, poor supply/return locations can increase power usage twofold, and extremely low emissivity produces a ±20% change in power-consumption depending on the room layout.