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。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 2505.99t(标 准 煤 当 量)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%。研究结果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 assisting heat pump for drying is an effective solution to achieve carbon emission reduction. A solar assisting 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 system increases 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 assisting transcritical CO2 drying system, solar energy coupled with steam assising transcritical CO2 drying system operates with the lowest primary energy consumption and carbon emission throughout the whole life time, which are 2 505.99 tce and 5 411.96 t, respectively. Compared with the steam assisting 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 coupled with steam assisting transcritical CO2 high temperature heat pump drying system takes 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.