CO₂ systems used in refrigeration are becoming more complex with the aim of improving their energy performance. Parallel compression is one of the implemented solutions to enhance the performance of the plants. However, an optimization process is required to operate this system at high performance and its operation is subjected to physical limitations in real plants.

This work presents the experimental optimization of a transcritical CO₂ plant working with parallel compression. The plant is tested at different discharge pressures and different secondary compressor speeds in order to optimize the COP of the plant and determine the optimal conditions for three gas-cooler exit temperatures 27.5 °C, 32.5 °C and 37.5 °C and three evaporation levels: −15.0 °C, −10.0 °C and −5.0 °C.

The optimal working conditions that can be achieved in a real plant have been determined, obtaining COP from 1.71 to 2.63 for −5.0 °C, from 1.50 to 2.22 for −10.0 °C and from 1.25 to 1.84 for −15.0 °C. Cooling capacity ranges from 8.94 kW to 11.34 for −5.0 °C, from 7.71 kW to 9.47 kW for −10.0 °C and from 6.22 kW to 7.76 kW for −15.0 °C. The trends observed in theoretical results have been corroborated and the optimum gas-cooler and intermediate pressures have been determined and discussed.

制冷中使用的CO ₂系统正变得越来越复杂，目的是提高其能源性能。并行压缩是提高工厂性能的已实施解决方案之一。但是，需要一个优化过程才能使该系统高性能运行，并且其运行在实际工厂中受到物理限制。

这项工作介绍了采用平行压缩的跨临界CO ₂装置的实验优化。在不同的排气压力和不同的二级压缩机转速下对设备进行测试，以优化设备的COP并确定三种气体冷却器出口温度27.5°C，32.5°C和37.5°C以及三种蒸发水平的最佳条件： -15.0°C，-10.0°C和-5.0°C。

确定了在实际工厂中可以实现的最佳工作条件，对于-5.0°C，COP为1.71至2.63；对于-10.0°C，COP为1.50至2.22；对于-15.0°C为1.25至1.84。对于-5.0°C，冷却能力的范围为8.94 kW至11.34，对于-10.0°C，冷却能力的范围为7.71 kW至9.47 kW，对于-15.0°C，冷却能力的范围为6.22 kW至7.76 kW。理论结果中观察到的趋势得到了证实，确定和讨论了最佳的气体冷却器和中间压力。