Thermo-economic assessment of a combined cooling and heating system with energy storage device

Large cold chain and food processing enterprises simultaneously require both high-temperature hot water and low-temperature quick freezing capabilities. To achieve an efficient and cost-saving solution of cooling and heating supply with waste heat recovery in the food processing, a novel combined cooling and heating supply system with energy storage (CCHES) is proposed. In this novel system, a cascade heat pump cycle is used to product the hot water with 100 degrees C for thermal food processes and a cascade absorption -compression refrigeration cycle is used to recover the waste heat from hot wastewater during the food processing and provide the cooling capacity with -30 to -50 degrees C for deep freezing. A hot water tank is added in this novel system for energy storage. A thermo-economic model is developed to analyze the thermodynamic performances and economic advantages of this novel system and an optimization is conducted by discussing parameters effects including the generator temperature and two kinds of evaporation temperatures. The results show that the optimal middle temperature is 10 degrees C, which cannot be impacted by two evaporation temperatures. Additionally, the corresponding optimal SENE, COPACS and ECOP are 1.35, 1.78 and 0.284. The CCHES recovers waste-heat capacity accounting for 96.1 % of provided heating capacity. The total cost of CCHES within 25 operation years is 8.33 x 106$, inducing savings of 3.2 x 105$ compared to the total cost of a system without energy storage device.