Theory vs. Practice in Direct Evaporative Roof Spray Cooling

Abstract

This paper will examine in depth the development of roof spray cooling in this country and elsewhere, the theory and practice of roof cooling, and the limits of system application. While this relatively simple method of air conditioning has been around for some time, and is being employed increasingly by large U.S. industrial firms, its operation, principles, and application, both empirically and practically, have not been widely discussed. The impact of roofing construction, building location, and internal and external load on the effectiveness of roof cooling will be considered. Also discussed will be the theoretical and actual effect of roof cooling on a facility's energy consumption, and on internal temperature variations where there is no mechanical air conditioning. A complete survey of most studies and findings to date will be presented. Guidelines for consideration of roof spray cooling systems will be developed incorporating ASHRAE methodology.