16 September 2011
The system described in this paper stores natural energy collected at low
temperatures during winter in the ground under a building, and it uses this energy for airconditioning in summer. This is an innovative seasonal thermal-storage system that is costeffective because the necessity for additional piping work for the heat exchange is avoided by embedding the pipes in the structural pile foundations. An HVAC system simulation tool was developed to analyze the performance of the system, and the results were verified using the measured data. Then, the conditions of optimal operation were investigated and applied
to the real system every year. As a result, the system coefficient of performance (COP) was improved, reaching 7.14 in the third year of operation, as compared to 3.61 at the beginning.