直接膨胀式地源热泵设计工况探讨

Discussion on design conditions for direct-expansion ground-source heat pump

对直接膨胀式地源热泵的运行工况进行了测试和分析.结果表明：直接膨胀式地源热泵压缩机不能直接按名义工况的制冷量或制热量来选型,而是在考虑冷热负荷不同的地区特性,以全年主要的运行工况为选型依据.夏季单U埋地换热器的出口温度按全年平均空气温度加上5～8℃来设计；冷凝温度按全年平均空气温度加上11～ 13℃来确定；蒸发温度按标准空气源热泵（AHRI）的名义工况7.2℃来确定.

The operation conditions of direct-expansion ground-source heat pump （DX-GSHP） sys- tems were analysed. The results indicate that the selection of DX-GSHP compressor cannot be fully based on standard rating condition. The annual main operation mode can serve as a basis for equip- ment selection while considering the load difference of the areas and zones. The designed outlet-tem- perature of the single U-bend loop ground heat exchanger can be set at annual average air tempera- ture plus 5 - 8 ℃, whereas the condensing temperature is set at annual average air temperature plus 11 -13 ℃. The evaporating temperature is set at 7.2 ℃, the nominal refrigeration capacity testing working condition of summer for air source heat pump unit specified by Air-conditioning, Heating and Refrigeration Institute （AHRI）.