Performance analysis of flash cascade heat pump drying system with heat recovery
Addressing the issues of traditional single-stage heat pumps whose efficiency deteriorates rapidly with increased temperature requirements and the significant energy waste caused by direct discharge of residual heat from auxiliary condensers,this work proposes a Heat Recovery Flash Evaporation Cascade Heat Pump Drying System(HR-FCHP)that leverages the benefits of low-temperature drying in the early stages of the process to enhance the external quality of materials.By incorporating the characteristics of a two-stage compression heat pump,this system couples the auxiliary condenser heat recovery with cascaded temperature drying.A thermodynamic model is established and validated using data from published literature.And a comprehensive thermodynamic analysis of the system is conducted to investigate the influence of key parameters on the operational efficiency of the proposed HR-FCHP system.Simultaneously,the proposed system is compared with a single-stage heat pump drying system(SSHP),a basic cascaded heat pump drying system(FCHP),and a parallel condenser heat pump drying system(PCHP)under the same operating conditions.To facilitate the validation of the energy-saving and drying efficiency of the proposed HR-FCHP system,an additional auxiliary condenser heat dissipation subsystem is incorporated into the three comparative heat pump subsystems,all of which feature a closed drying subsystem.This subsystem aims to recover and utilize excess heat for pre-drying the drying materials.The results indicate that the proposed HR-FCHP system has higher energy-saving and drying efficiency compared to the SSHP,FCHP,and PCHP systems.The coefficient of performance for heating(COPh)and specific moisture extraction rate(SMER)of HR-FCHP system are 5.40 and 4.31 kg/kWh,which are 53.85％and 65.77％,33.00％and 20.73％,and 7.14％and 9.40％higher than the COPh and SMER of the SSHP,FCHP,and PCHP systems,respectively.Additionally,the HR-FCHP system has the lowest initial cost(CIC)at 66 400 CNY,and its life cycle cost(CLCC)can be reduced by 69.86％,40.92％,and 8.57％compared to SSHP,FCHP,and PCHP systems,respectively.This novel heat pump drying system can serve as a theoretical foundation for future experimental research and practical applications.
heat recoveryflashcascade heat pumpdryingthermodynamic model
万方数据
维普
