Center for the Built Environment

Thermally activated building systems (TABS) are gaining popularity as a potentially energy efficient strategy for conditioning buildings. These systems can use large surfaces for heat exchange, and the temperature of the cooling water can be only a few degrees lower than the room air temperature. This small temperature difference allows the use of alternative cooling sources, for example, indirect/direct evaporative cooling, to possibly eliminate refrigerant cooling to reduce energy consumption.  In addition, TABS allow the potential to reduce the electric power demand of the building if a night time precooling strategy is used. This research has investigated the application range of using slab-integrated hydronic radiant cooling (TABS) with a cooling tower providing chilled water as the primary way of conditioning the building. The objectives of this study were the following: 1)quantify the climatic limits of using evaporative cooling (cooling tower) for radiant ceiling slab system; 2) identify design options to expand the application; and 3) provide climate based advice for system design and operation.