Retrofit and economic analysis of thermal storage using an existing fire tank

Presents the method in thermal storage retrofitting using an existing fire tank for a large supermarket air conditioning system. Suggests that two cold sources shall be connected indirectly with plate heat exchangers, and that the optimized water flow and temperature of chiller and thermal tank be determined by considering both the temperature difference and the operating condition of air conditioning terminal units, and that the terminal load be checked in design process when flow rate and temperature changed for the temperature rising characteristic of terminal units, and that design of the water distributor is the main factor in determining the thermal tank efficiency, which should satisfy the requirement of Froude number and Reynolds number. Analysing result of annual operating costs shows that the static payback period of the retrofit is only 1.3 years.