In order to maximize the recovery of heat energy from shower greywater, improve the operation stability of the wastewater source heat pumps and reduce the complexity of the system, a serially cascaded wastewater source heat pumps (SCWSHP) with large temperature difference was proposed. In this paper, an experimental system for testing the heating performance of the SCWSHP was built. The heating performance of the SCWSHP was analyzed under various operating conditions. And the operating conditions of the SCWSHP were discussed in order to realize that the amount of hot water heated by the SCWSHP is greater than the amount of greywater recovered. The results showed that when the greywater inlet temperature and out temperature are 30 °C and 6 °C, respectively, the outlet temperature of hot water can be heated to 50 °C if tc,i is 15 °C. But the maximum outlet temperature of hot water can only reach 41 °C if tc,i is 9 °C in order to guarantee the operation demand of the system. For the lower tap water inlet temperature, the shower greywater inlet temperature must be increased in order that the hot water outlet temperature can reach 45 °C. If t_c,i is 6 °C, the greywater inlet temperature should be improved to 35 °C. As long as the outlet temperature of hot water meets the operation requirements, the hot water flow rate should be increased as much as possible, but the flow rate of greywater should be consistent with that of hot water. The results can provide key references for design and operation of the SCWSHP system.

为了最大限度地利用淋浴灰水回收热能，提高废水源热泵的运行稳定性，降低系统的复杂性，提出了一种温差较大的串联级联废水源热泵（SCWSHP）。在本文中，建立了一个用于测试SCWSHP加热性能的实验系统。在各种操作条件下分析了SCWSHP的加热性能。并讨论了SCWSHP的运行条件，以了解SCWSHP加热的热水量大于回收的中水量。结果表明，当灰水进口温度和出水温度分别为30°C和6°C时，如果tc，i为15°C，热水的出口温度可以加热到50°C。但是，如果tc，i为9°C，热水的最高出口温度只能达到41°C，以保证系统的运行需求。对于较低的自来水入口温度，必须提高淋浴灰水的入口温度，以使热水出口温度达到45°C。如果t _c，i为6°C，灰水进口温度应提高到35°C。只要热水的出口温度满足操作要求，就应尽可能提高热水的流量，但中水的流量应与热水的流量保持一致。研究结果可为SCWSHP系统的设计和运行提供关键参考。