A novel method for finding the optimal heat storage tank capacity for a cogeneration power plant

The introduction of a heat storage tank (HST) into a cogeneration power plant was considered in this paper. The power plant investigated consisted of multiple power production units and operated in a two-tariff electricity pricing market. The HST tank capacity was optimized for maximum profits with and without consideration of the investment costs. When the investment costs were included in the optimization, the optimal HST capacity was nearly halved. Optimal sizing of the HST using heat consumption data from prior years requires over one thousand variables in the mathematical model. A novel method was proposed to drastically reduce the number of variables and find the optimal HST capacity using existing optimization algorithms on a typical computer. The results show that introduction of an HST to electrical and thermal energy generation can increase profits and thermal production capacity of the combined cycle power plant.