Economic feasibility of thermal energy storage systems: Application to Al-Haram Grand Holy Mosque

In hot aired countries with sever weather, cooling and airconditioning of buildings contributes significantly to the electricitypeak demand, which normally occurs during noontime period. Shiftingthe electrical loads to off-peak periods is achieved by introducing timeof rate tariff as incentive control on the demand-side and/or usingactive thermal energy storage technology. This paper investigates theeconomic feasibility of both building an ice thermal energy storageand a timely based tariff structure for the unique air conditioning plantof the Grand Holy Mosque of Makkah, Saudi Arabia (the largestreligious building on earth). The features of the building are uniquewhere the air-conditioned 39300 m2 zone is open to the atmosphereand the worshippers fully occupy the building 5 times a day. Hundredsof thousands of worshippers attend the blessed Friday prayer atnoontime, which escalates the peak electricity load. For economicanalysis, the objective function is the daily electricity bill that includesthe operation cost and the capital investment of the ice storage system.The operation cost is a function of the energy imported for operatingthe plant in which the tariff structure, number of operating hours andthe ambient temperature are parameters. The capital recovery factor iscalculated for 10% interest rate and payback period of 10 years. Fulland partial load storage scenarios are considered.The results showed that with the current fixed electricity rate (0.07$/kWh), there is no gain in introducing ice storage systems neither forfull nor for partial storage schemes. Combining energy storage and anincentive time structured rate showed reasonable daily bill savings. Forbase tariff of 0.07 $/kWh during daytime operation and 0.016 $/kWhfor off-peak period, savings of 549.4 $/d was achieved for full loadstorage scenario. the storage capital cost will be paid in 10 years andafterwards the daily saving in operational cost will be 4011.76 $/d.