A prototype CO₂ ground-source heat pump (GSHP), i.e. a water-to-air heat pump designed to couple with a ground heat exchanger, was tested in cooling mode per ISO standard 13256-1 to provide experimental data for assessing and improving CO₂-based GSHPs. The GSHP consisted of a vapor-compression cycle with a liquid-line/suction-line heat exchanger (LLSL-HX). The system operated in a subcritical cycle for antifreeze entering liquid temperature (ELT) ≤ 25 °C and a transcritical cycle for ELT > 25 °C. The ‘Standard’ condition metrics were: coefficient of performance (COP) 4.14, total capacity 6690 W, sensible capacity 5400 W, and sensible-heat ratio (SHR) 0.81. The ‘Part-load’ performance was: COP 4.92, total capacity 7240 W, sensible capacity 5640 W, and SHR 0.78. The GSHP was also tested at additional ELTs ranging (10 to 39) °C, where COP ranged (7.3 to 2.4). Compressor efficiency correlations were shown for these and 118 additional tests. The LLSL-HX was estimated to reduce COP by (0 to 2)% for ELTs ranging (10 to 25) °C, and increase COP by (0 to 5)% for ELTs ranging (30 to 39) °C. At the ‘Standard’ condition the major exergy defects were compressor 0.32, ground heat exchanger 0.19, condenser 0.11, evaporator 0.11, EEV 0.07, pump 0.07, and fan 0.04. The exergy defects were sensitive to ELT, though the compressor was always the largest. Estimated performance of the cycle without the LLSL-HX showed for ELT (10 to 39) °C the HX reduced the EEV throttling defect by (0 to 0.08) and compressor defect by (0 to 0.015), but increased the condenser/gas-cooler defect by (0 to 0.06).

原型 CO ₂地源热泵 (GSHP)，即设计为与地热交换器耦合的水-空气热泵，根据 ISO 标准 13256-1 在冷却模式下进行测试，为评估和改进提供实验数据CO ₂基于 GSHP。GSHP 由带有液体管线/吸入管线热交换器 (LLSL-HX) 的蒸汽压缩循环组成。该系统在防冻液进入液体温度 (ELT) ≤ 25 °C 的亚临界循环和 ELT > 25 °C 的跨临界循环中运行。“标准”条件指标是：性能系数 (COP) 4.14、总容量 6690 W、显热容量 5400 W 和显热比 (SHR) 0.81。“部分负载”性能为：COP 4.92，总容量 7240 W，显能容量 5640 W，SHR 0.78。GSHP 还在额外的 ELT 范围（10 到 39）°C 下进行了测试，其中 COP 的范围是（7.3 到 2.4）。显示了这些和 118 个附加测试的压缩机效率相关性。估计 LLSL-HX 将 COP 降低 (0 到 2)%，适用于范围 (10 到 25) °C 的 ELT，并将 COP 增加 (0 到 5)%，用于范围 (30 到 39) °C 的 ELT。在“标准”条件下，主要的火用缺陷是压缩机 0.32、地热交换器 0.19、冷凝器 0.11、蒸发器 0.11、EEV 0.07、泵 0.07 和风扇 0.04。尽管压缩机总是最大的，但火用缺陷对 ELT 很敏感。没有 LLSL-HX 的循环的估计性能显示，对于 ELT（10 到 39）°C，HX 将 EEV 节流缺陷减少（0 到 0.08）和压缩机缺陷（0 到 0.015），但增加了冷凝器/气体-冷却器缺陷减少（0 到 0.06）。