Exergy analysis of a new spray cooling system-based PV/T and heat recovery with application in sow houses

Abstract

The uncertain cooling effect and additional huge primary energy consumption caused by humidity regulation are currently the main problems of traditional environmental regulation systems in sow houses. In this study, a new spray cooling system is proposed based on PV/T and heat recovery in sow houses. Meanwhile, the mathematical models are established for its key equipment and their reliability is verified according to literature data. The results show that the maximum error is less than 14.5 % for the models. Based on the above models, the annual operation modes are determined for the new system. Specifically, its annual operation modes mainly include the cooling season, the heating season, the transitional spring and the transitional autumn. Meanwhile, the exergy loss and energy consumption are analyzed for the new system in four seasons through simulation. The results show that in the cooling and heating seasons, the exergy loss first decreases and then increases with the increase of spray power (SP) and mass flow rate of circulating water (MFRW). In the transition season, the exergy loss decreases with the increase of MFRW, while it first decreases and then increases with the increase of SP. However, the annual energy consumption increases with the increase of SP and MFRW. Aim at the minimum exergy loss of new system, its optimal control parameters are obtained in four seasons through optimization. Specifically, when the mass flow rate of supply air is the minimum ventilation rate required by sows, the optimal SP and MFRW are recommended as 40 kW and 12245 kg/h in the cooling and heating seasons, respectively. Meanwhile, they are recommended as 35 kW and 12245 kg/h in the transition season, respectively. The above research can provide guidance for the improvement of traditional spray cooling systems and the performance optimization of new system.