Assessment of practical applications of outdoor air economizer in Hong Kong

In Hong Kong, it is usually thought that the use of an economizer is not beneficial. Comparative studies on outdoor air conditions in urban, suburban and rural areas show that use of economizers in suburban areas is feasible. The potential for use of economizers in suburban and rural areas is significantly higher than that in urban areas, and might be higher than that claimed on the basis of Hong Kong weather data reported by the Hong Kong Observatory. An in-situ monitoring exercise on an enthalpy-based economizer in a building shows that over 40% reduction in refrigeration load is achieved in the entire winter period (over 10% in a year) in a suburban area. The use of partial and total free cooling does not cause humidity problem but improves the indoor air quality.