Economic feasibility of thermal energy storage systems : application to al-Haram grand holy mosque air conditioning plant

الملخص EN

In hot aired countries with sever weather, cooling and air conditioning of buildings contributes significantly to the electricity peak demand, which normally occurs during noontime period.

Shifting the electrical loads to off-peak periods is achieved by introducing time of rate tariff as incentive control on the demand-side and/or using active thermal energy storage technology.

This paper investigates the economic feasibility of both building an ice thermal energy storage and a timely based tariff structure for the unique air conditioning plant of the Grand Holy Mosque of Makkah, Saudi Arabia (the largest religious building on earth).

The features of the building are unique where the air-conditioned 39300 m2 zone is open to the atmosphere and the worshippers fully occupy the building 5 times a day.

Hundreds of thousands of worshippers attend the blessed Friday prayer at noontime, which escalates the peak electricity load.

For economic analysis, the objective function is the daily electricity bill that includes the operation cost and the capital investment of the ice storage system.

The operation cost is a function of the energy imported for operating the plant in which the tariff structure, number of operating hours and the ambient temperature are parameters.

The capital recovery factor is calculated for 10 % interest rate and payback period of 10 years.

Full and 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 for full nor for partial storage schemes.

Combining energy storage and an incentive time structured rate showed reasonable daily bill savings.

For base tariff of 0.

07 $ / kWh during daytime operation and 0.016 $/kWh for off-peak period, savings of 549.4 $ / d was achieved for full load storage scenario.

the storage capital cost will be paid in 10 years and afterwards the daily saving in operational cost will be 4011.

76 $ / d.Different tariff structure is discussed and the break-even nighttime rate was determined (varies between 0.

008 and 0.

03 $ / kWh).

Partial load storage scenario showed to be unattractive where the savings for the base structured tariff was insignificant.