食品零售业，尤其是超市对制冷的需求，目前约占英国商店总能耗的30%至60%。这种消耗的一个关键特征是冷凝装置向环境空气排出大量低品位热量。本研究的重点是跨临界CO2（R744）制冷循环，目的是评估使用水冷式冷凝器通过中间闭环水回路向土壤散热是否可以改善整体冷却性能，同时还考虑了这种改造的经济影响。在这项工作中，提出了一个模拟现有超市制冷系统运行的详细模型，并根据英国一家超市制冷系统的现场数据测量进行了验证。所检查的直接膨胀系统包括一个空气压缩机- 冷却冷凝器与两套压缩机耦合，用于提供中低温冷却。然后对该基准模型进行修改，并用于评估类似系统的性能，该系统使用水冷式冷凝器代替现有的风冷机组或与其并联。初步结果表明，当外部温度较高时，使用水冷式冷凝器有可能将这些制冷系统的能耗降低多达5倍。然而，在寒冷的环境条件下，风冷冷凝器排出的热量减少了10%，从而提高了系统性能。此外，为了检查现有系统的年度运行情况，并将其与各种水冷替代方案进行比较，还进行了更全面的案例研究。分析表明，水消耗的能量减少了约3%- 冷却系统（与参考基准风冷系统相比），对于并联运行的风冷和水冷冷凝机组耦合的混合系统，降低了近6%。对这些系统进行的经济评估表明，对于一家大型超市（1400平方米（15000平方英尺）），使用水冷式冷凝器的系统每年可以降低高达4300美元（3450英镑）的电力成本。该系统的年维护成本每年增加约600美元至1000美元（500英镑至800英镑），资本成本略微降低不到5%，这使得该系统安装在新店时，投资回收期不到5年的商业制冷成为一项有希望的投资。引用:2017年年度会议，加利福尼亚州长滩，会议论文

The need for refrigeration in the food retail industry and specifically in supermarkets, currently accounts for about 30% to 60% of the total energy consumed in the UK stores. A key characteristic of this consumption, is the high amount of low-grade heat rejected by the condensation units to the ambient air. The aim of this study, which focuses on transcritical CO2 (R744) refrigeration cycles, is to assess whether the use of a water-cooled condenser rejecting heat to the soil via an intermediate closed-loop water-circuit, can improve the overall cooling performance, while also considering the economic implications of this modifications. In this work, a detailed model simulating the operation of an existing supermarket refrigeration system is presented and validated against field data measurements taken from a refrigeration system in a UK supermarket. The examined direct-expansion system comprises an air-cooled condenser coupled with two sets of compressors for the provision of intermediate and low-temperature cooling. This baseline model is then modified and used to evaluate the performance of a similar system, in which a water-cooled condenser is used instead of the existing air-cooled unit or in parallel to it. Preliminary results indicate that the use of water-cooled condensers has the potential to reduce the energy consumption of these refrigeration systems by up to a factor of 5 when the external temperature is high. However, in cold ambient conditions, the air-cooled condensers reject 10% less heat, resulting in a better system performance. Furthermore, a more thorough case study is developed in order to examine the yearly operation of the existing system, and to compare this to various water-cooled alternatives. The analysis indicates a reduction of approximately 3% in the energy consumed by the water-cooled system (compared to the reference benchmark air-cooled system), and a reduction of almost 6%, for a hybrid system with coupled air-cooled and water-cooled condensation units in parallel operation. The economic evaluation of these systems shows that electricity costs can be reduced by up to $4300 (£3450) per year for a large supermarket (1400 m2(15000 ft2)) with a system using a water-cooled condenser. The annual maintenace costs of the system are increased by about $600-$1000 (£500-£800) per year, and the capital costs are marginally reduced by less than 5% leading to a promising investment for commercial refrigeration with a payback period of less than 5 years, when the system is installed in a new store.