Sizing room air conditioners used in sleeping environments in the subtropics

In the subtropics, room air conditioners (RACs) have been widely used to maintain an appropriate indoor thermal environment not only at day but also at night for sleeping. However, currently RACs are often sized by rules of thumb that are based on the applications and practices of air conditioning during daytime operating periods. A method of sizing RACs used in sleeping environments has been developed in this paper. The sizing of RACs used in sleeping environments in the subtropics should not be based on the peak load that occurs at the beginning of a night air conditioning process but preferably on 70–80% of the peak load for better indoor thermal comfort and higher energy efficiency.