Indoor thermal comfort and energy efficiency of various air-conditioning schemes for museum buildings

In museum buildings, air conditioning systems with precise thermal-hygrometric control of indoor environment are necessary for preventing degradation of artworks and providing a pleasant thermal environment for visitors. In traditional constant air volume (CAV) systems widely used in museums, the supply air is often cooled and then reheated for dehumidification without over-cooling conditioned spaces during warm and humid seasons. The cooling and reheating processes are energy-intensive. This paper presents a new air conditioning scheme for indoor thermal environment control in museums. The scheme integrates a dedicated outdoor air system (DOAS) with a CAV system. Control strategies are also developed for independent indoor temperature and humidity controls. Simulation tests are conducted to compare performances of a CAV system and the integrated system on the platform of TRNSYS. These two schemes are: (1) a CAV system with separate temperature and humidity controls by cooling-reheating; (2) a DOAS-integrated CAV system with independent indoor temperature and humidity controls. Simulation results show that the DOAS-integrated system is more energy efficient. It consumes about 60% less electricity than the CAV system with cooling-reheating on the test day. The DOAS-integrated scheme can also achieve satisfactory indoor thermal comfort considering the space temperature and relative humidity (RH). Both schemes can provide good indoor air quality measured by CO2 concentration.