太阳能辅助CO2高温热泵系统生命周期性能分析

Life cycle performance analysis of solar energy assisted CO2 high temperature heat pump system

中文关键词: 太阳能  二氧化碳  热泵系统  干燥  全生命周期  碳排放

英文关键词: solar energy  carbon dioxide  heat pump system  drying  life cycle  carbon emission

中文摘要:

      利用太阳能辅助热泵进行干燥应用是实现碳减排的有效手段。本文提出了太阳能辅助的跨临界CO2高温热泵干燥系统，并对系统的热力学特性和全生命周期能耗及排放特性模型进行分析。结果表明跨临界CO2高温热泵干燥系统在气体冷却器出现两个窄点时，取得最大COP及最优排气压力；跨临界CO2高温热泵干燥系统COP随空气在气体冷却器出口处温度的降低显著提升，出口温度由120℃降低至70℃，COP提升了6.32~31.45%。相对跨临界CO2干燥系统和蒸汽辅助跨临界CO2干燥系统，太阳能+蒸汽辅助蒸汽辅助跨临界CO2干燥系统的全生命周期一次能源消耗和碳排放量最低，分别为2505.99tce和5411.96t；相比蒸汽辅助跨临界CO2干燥系统，太阳能+蒸汽辅助跨临界CO2高温热泵干燥系统在使用天然气作为锅炉燃料时，气体污染物（SO2和NOx）和固体污染物（PM2.5和PM10）的排放量减少了40.49%。本文为高效低排放高温热泵干燥系统的构建和运行提供理论参考。

英文摘要:

      Utilizing solar energy assisted heat pump for drying is an effective solution to achieve carbon emission reduction. In this study, a solar assisted transcritical CO2 high temperature heat pump drying system is proposed, and the thermodynamic, life cycle energy consumption and emission performances of the system are analyzed. The results show the transcritical CO2 high temperature heat pump drying system achieves the maximum coefficient of performance (COP) and the optimum discharge pressure when two pinch points are achieved in the gas cooler. The COP of the transcritical CO2 high temperature heat pump drying system increased significantly with the decrease of air temperature at the outlet of the gas cooler. The COP increases by 26.32~31.45% as the outlet temperature decreasing from 120 to 70°C. Compared with transcritical CO2 drying system and steam-assisted transcritical CO2 drying system, solar energy + steam-assisted transcritical CO2 drying system operates with the lowest primary energy consumption and carbon emission throughout the whole life time, which are 2505.99tce and 5411.96t, respectively. Compared with the steam-assisted transcritical CO2 drying system, the emissions of gas pollutants (SO2 and NOx) and solid pollutants (PM2.5 and PM10) are reduced by 40.49% when the solar + steam-assisted transcritical CO2 high temperature heat pump drying system using natural gas as the fuel of boiler. This study can provide a theoretical reference for the development and operation of efficient high temperature heat pump drying system with low emissions.