Low-energy cooling for improved thermal comfort in offices

This study has explored the possibility and potential of using a thermal active mass system for reducing the temperature rise and increasing the thermal comfort in an office room. The Controlled Active Mass (CAM) will be used as a heat sink to absorb heat from the room in order to increase the thermal comfort. Physically, the CAM system was designed as a cubic-shaped tank filled with water, with the tank surfaces either polished or black. Full-scale laboratory measurements of the CAM system in an office room have been used to evaluate the temperature, air velocity and thermal comfort values, PMV, PPD and the equivalent temperature (teq). The measurements showed that, although the CAM size is relatively small compared to the office room, and the temperature difference between the room air and the temperature of the CAM is quite modest, the influence on the thermal comfort and indoor environment is quite apparent. This is particularly so when the surfaces of the CAM system are black, since the tank is able to absorb more heat from the room surfaces than can the polished CAM system. The CAM system does not cause any uncomfortable draughts and, since it is a low-exergy system, it has a considerable potential for future energy-efficient systems in buildings.