Possibilities and limitations for evaporative and dessicant cooling technologies.

Evaporative cooling is an interesting alternative to conventional compressor refigerationsystems for air-conditioning. However, the use of evaporative cooling presupposes all-airsystems and is, to a large extent, limited by ambient conditions as well as the settled demandson the indoor climate. High outdoor humidity levels have a great influence on the supply-airtemperature achievable, i.e. cooling loads possible to meet. One way to reduce the influenceof these limitations is to use desiccant cooling, i.e. to dehumidify the ambient air before theevaporative stages. Here, a general methodology to describe possibilities and limitations forevaporative and desiccant cooling, is presented. The major advantage of using this methodologyis that this may give rise to an increased understanding of these processes. This methodologycan also be used for a rough estimation of the energy consumption for air-conditioningusing evaporative or desiccant cooling. As an example, this methodology is applied oncooling loads of a base-case office building situated in Stockholm, Sweden.