An analysis of the fresh air load reduction system by using underground double floor space for air conditioning

This paper presents a feasibility study of a fresh air load reduction system by using an underground double floor space. The system was introduced into a real building (Aichi Children’s Center in Japan) and was examined by the field measurement. Judging from the measurements during two years (summer, 1996 ~ summer, 1998), the state of the system operation was very stable through this period and it was clear that the system contributes to reduction of energy consumption for air-conditioning. Furthermore, a simulation model used the simple heat diffusion equation was developed to simulate its thermal characteristics and performances. The simulations resulted in air temperature in good agreement with the measurements. Also, from the result of numerical analysis, it is clear that the amount of heat supply by using this system is more than the amount of energy loss to the room above it. Therefore, it is concluded that this system is very useful and the proposed numerical model can be used for the prediction of system thermal performance.