Economic viability for the synthesis of multiperiod thermal-driven chilled water network

Abstract

The thermal-driven refrigeration system (TRS) has emerged as a green solution in the chilled water system due to its ability to recover waste heat. However, the implementation of TRS in multiperiod thermal operations is not as straightforward as in continuous process because the heat source does not always match with the cooling sink at a particular time period. This imposed difficulties in achieving an optimal solution for simultaneous waste heat recovery and the chilled water supply. Previous literature focused on the continuous process waste heat recovery in chilled water generation. In this paper, a multiperiod mathematical optimization model with variable cooling demand and waste heat supply is developed to achieve maximum waste heat recovery through the integration of thermal energy storage (TES). From the optimization results, the TES-TRS scheme decreased the capital cost by 15% through the reduction of chiller capacity and quantity; promoted the energy efficiency by storing the excess waste heat for subsequent periods with waste heat deficit. Finally, 39% improvement in waste heat recovery and 30% reduction in total annualized cost are accrued from the implementation of TES-TRS scheme as compared to the base case without TES.