制冷与空调

为探究电动汽车R290热泵空调系统回热循环及基本循环的性能差异，设计并搭建了带回热器的R290二次回路热泵空调系统，在-25～50℃环境温度下对比了有/无回热系统的制冷与制热性能，以及系统从启动状态至设定状态对系统回热性能的影响，并对系统进行了（火用）分析。结果表明，回热循环均能提高系统的制冷量、制热量及COP值。在43℃/27℃(车外/车内)工况下，制冷量和COP值分别提高6.64%和5.74%;在-25℃/20℃(车外/车内)工况下，制热量和COP值分别提高5.07%和3.17%。回热器的（火用）效率与回热器低压侧压降呈明显的负相关关系。制冷循环下的低压侧压降显著大于制热循环，因此，制冷循环下的回热器（火用）效率低于制热循环。系统运行状态的变化通过影响车内进风温度进而影响回热器低压侧压降，造成了回热器（火用）效率的变化。从启动状态至设定状态时，制冷工况下，回热器低压侧压降增加83.84%,（火用）效率减少w6%;制热工况下，低压侧压降降低38.46%,（火用）效率增加1%。

To investigate the performance differences between the regeneration cycle and the basic cycle of R290 heat pump air conditioner systems for electric vehicles, the research designs and builds a R290 heat pump air conditioner system with secondary loop and regenerator. The heating and cooling performance of the system with and without regenerator is compared at an ambient temperature range of-25 ℃ to 50 ℃. and the influence of system start-up state/set-up state on the regeneration performance is investigated, and the exergy analysis of the system is further analyzed. The results show that regeneration can significantly improve heating and cooling performance of the R290 heat pump. At 43 ℃/27 ℃(outside/inside the vehicle), the cooling capacity and COP of the regeneration system are increased by 6.64% and 5.74% respectively; at-25 ℃/20 ℃(outside/inside the vehicle), the heating capacity and COP of the regeneration system are increased by 5.17% and 3.17% respectively. There is a significant negative correlation between the exergy efficiency of the regenerator and the pressure drop at the low pressure side of the regenerator. The pressure drop on the low pressure side in the cooling cycle is significantly larger than that in the heating cycle, and therefore the exergy efficiency of the regenerator in cooling cycle is less efficient than that in heating cycle. Changes in system operational status cause a change in exergy efficiency of regenerator by affecting temperature inside the vehicle and thus the pressure drop on the low pressure side. The pressure drop at the low pressure side of the internal heat exchanger increases by 83.84% and the exergy efficiency decreases by 6% when system goes from the start-up state to set-up state under refrigeration condition; the pressure drop at the low pressure side of the internal heat exchanger decreases by 38.46% and the exergy efficiency increases by 1% when system goes from the start-up state to set-up state under heating condition.