Energy conservation for operation theatres by secondary return air system

The traditional ways of maintaining cleanliness, temperature and moisture level in anoperation theatre (OT) usually use larger HVAC system and keep both the heating andcooling functions operating at the same time. The temperature and moisture level are thusunder control at the cost of tremendous amount of wasted energy. Incorporating the HVACsystem with the newly developed secondary return air system, the system capacity can bereduced while the energy efficiency can be increased. In this paper, concepts of the secondaryreturn air system are described. The influential factors of sensible heat ratio and air changerate of the secondary return air system on energy saving are discussed. An in-house computerprogram that was developed for calculating the systems operation points and the performanceof energy conservation were used in this research.