In this paper, a methodology is presented to determine the optimal chilled water storage (CWS) capacity
and corresponding operating strategy for the air conditioning loads for different electricity tariff. Several
scenarios were studied for the KMUTNB air conditioning system. It was concluded that the CWS with
a chiller of 450 RT (2 units) running continuously, thermal-energy storage of 9413 RT-h and 5175 m3
volume was most suitable. The mechanical chiller (MAC) capacity and peak demand could be decreased
by over 2 times and 31.2% respectively. It can move the energy consumption from the on peak to the off
peak periods by 35.7%. The economics result showed PB, IRR and NPV are 10 y, 21% and 0.834 MUS$
compared with the existing system.