Cold water storage tank enhancement using response surface methodology leading cooling peak shaving along with load shifting

Abstract

In hot areas, electricity consumption in the cooling sector holds 66% of the electricity usage by residential buildings. The need for electricity during peak times causes various problems in the electricity supply network. Adding a cold water storage tank can achieve two goals: 1- peak load shifting and 2- peak load shaving. In this study, first, the volume of the storage tank was calculated by energy analysis for the day with the maximum cooling needs. Owing to installing the tank, the electricity consumption not only reaches zero during the peak time (7 a.m.–11 p.m.) but also the total electricity demand decreases by 5.1%. According to the ASHRAE, throughout the 8760 h in one year, the deviation of the interior temperature from the setpoint should not exceed the 300-h threshold (i.e., unmet hours <300 h). Considering the allowable amount of unmet hours as a constraint, optimal points were acquired using Response Surface Methodology (RSM). This method reduces the cold storage tank by 40% and decreases the electricity need by 16.5% compared to the reference case (without a storage tank). Furthermore, the optimal storage tank eliminates the cooling-associated electricity demand to zero during peak periods.