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The Chinese Journal of Process Engineering ›› 2024, Vol. 24 ›› Issue (10): 1230-1240.DOI: 10.12034/j.issn.1009-606X.224029

• Research Paper • Previous Articles     Next Articles

Performance analysis of flash cascade heat pump drying system with heat recovery

Huipeng YANG1,2,3,  Kai YE2,  Longxiang CHEN2,3*   

  1. 1. College of Mechanical and Electrical Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China 2. Quanzhou Institute of Equipment Manufacturing, Haixi Institutes, Chinese Academy of Sciences, Jinjiang, Fujian 362000, China 3. Fujian College, University of Chinese Academy of Sciences, Fuzhou, Fujian 350000, China
  • Received:2024-01-19 Revised:2024-04-09 Online:2024-10-28 Published:2024-10-29
  • Contact: Long-Xiang LongxiangChen chenlx@fjirsm.ac.cn

带热回收的闪蒸级联热泵干燥系统性能分析

杨惠鹏1,2,3， 叶楷2， 陈龙祥2,3*   

  1. 1. 福建农林大学机电工程学院，福建 福州 350002 2. 中国科学院海西研究院泉州装备制造研究中心，福建 晋江 362000 3. 中国科学院大学福建学院，福建 福州 350000
  • 通讯作者: 陈龙祥 chenlx@fjirsm.ac.cn
  • 基金资助:
    福建省科技计划项目;泉州市科技计划项目

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Abstract: 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 66400 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.

Key words: heat recovery, flash, cascade heat pump, drying, thermodynamic model

摘要： 针对传统单级热泵的效率随着温升要求的提高急剧恶化及辅助冷凝器余热直接排出造成巨大能源浪费的问题，本工作结合干燥过程前期较低温度干燥对物料烘干品质的提升具有促进作用的特点，提出了带热回收闪蒸级联热泵干燥系统(HR-FCHP)。本工作建立了热力学模型，采用文献中的数据进行验证，并对系统进行了全面的热力学分析，同时将所提系统与单级热泵干燥系统(SSHP)、基础闪蒸级联热泵干燥系统(FCHP)和并联冷凝器热泵干燥系统(PCHP)在相同的运行工况下依次进行对比。结果表明，较于SSHP, FCHP和PCHP系统，所提出的HR-FCHP系统具有更高的节能效果和干燥效果，其系统能效比(COPh)和单位能耗除湿量(SMER)为5.40与4.31 kg/kWh，与SSHP, FCHP和PCHP系统的COPh和SMER相比分别高出53.85%和65.77%、33.00%和20.73%以及7.14%和9.40%。此外，所提HR-FCHP系统的初始投资成本(CIC)最低，为6.64万元，该系统的生命周期成本(CLCC)分别比SSHP, FCHP和PCHP系统降低了69.86%, 40.92%和8.57 %。

关键词: 热回收, 闪蒸, 级联热泵, 干燥, 热力学模型