Experimental analysis of the R744 vapour compression rack equipped with the multi-ejector expansion work recovery module.

A test facility for experimental investigation of the R744 vapour compression rack equipped with the multi-ejector expansion work recovery module was designed and manufactured. Comparison of the R744 multi-ejector refrigeration system with the R744 parallel compression system on the same test facility was carried out based on energy performance characteristics: refrigeration capacity, power consumption, COP, and exergy efficiency. Apart from the system performance comparison, influence of the pressure level in the flash tank on the system performance for both alternatives was analysed. The experimental results indicated COP and exergy efficiency improvement of the multi-ejector refrigeration system up to 7% and 13.7%, respectively. The highest values of COP and the exergy efficiency were obtained by the multi-ejector refrigeration system for the tanks pressure lift value close to the limit value. The values of the overall compressor efficiencies were significantly differentiated, dependent on the operation module (cooling load and heat rejection conditions), which strongly influenced the values of COP, and the exergy efficiency.

本研究设计并搭建了一套实验台架，用于对搭载多喷射器膨胀功回收模块（multi-ejector expansion work recovery module）的R744蒸汽压缩式机架机组开展实验研究。基于制冷量、功耗、COP（Coefficient of Performance，制冷系数）与㶲效率（exergy efficiency）等能效性能特性，在该实验台架上完成了R744多喷射器制冷系统与R744并联压缩系统的性能对比测试。除系统性能对比外，本研究还分析了闪发罐（flash tank）内压力水平对两种系统运行性能的影响。实验结果表明，多喷射器制冷系统的COP与㶲效率分别最高可提升7%与13.7%。当闪发罐压力提升值接近极限值时，多喷射器制冷系统的COP与㶲效率可达到最优水平。整体压缩机效率的数值会随运行工况（冷却负荷与排热条件）发生显著差异，该因素对COP及㶲效率的数值具有显著影响。