Experimental Study on Effect of Water Flow Rate on Heating Performance of a Series Bathing Wastewater Source Heat Pump Hot Water Unit

  • Liangdong Ma
  • Tixiu Ren
  • Tianyi ZhaoEmail author
  • Jili Zhang
Conference paper
Part of the Environmental Science and Engineering book series (ESE)


To maximize the recovery of heat energy from bathing wastewater, a two-series-connected bathing wastewater source heat pump hot water unit (SCBWSHP) with large temperature difference was proposed. Its rated design parameters are: the inlet and outlet temperatures of the bathing wastewater are 30 °C and 6 °C, respectively. The tap water inlet temperature is 10 °C, and the hot water outlet temperature is 45 °C. The effects of the mass flow rate of the tap water and the bathing wastewater on heating performance of the SCBWSHP were investigated experimentally. The results showed that the COP of the whole unit is 4.5 at the ratings. When the tap water mass flow rate increases from 600 to 900 kg/h, the whole unit COP increased by 18.7%, from 3.20 to 4.88. And the COP of the whole unit increases from 4.03 to 4.83 as the bathing wastewater mass flow rate rises from 600 to 1000 kg/h, increased by 16%.


Bathing wastewater Heat pump unit Large temperature difference Coefficient of heating performance Experimental research 



Specific heat at constant pressure, J/(kg K)


Coefficient of heating performance


Mass flow rate of tap water, kg/s


Mass flow rate of bathing wastewater, kg/s


Heating capacity, W


Heat quantity removed from wastewater, W


The temperature of tap water, K


The temperature of bathing wastewater, K


Condensing temperature, K


Evaporating temperature, K


Electric motor power of the compressor, W



High-temperature-zone-cycle unit


Low-temperature-zone-cycle unit


The whole unit



The authors are grateful to the financial support by the National Natural Science Foundation of China (No. 51676026).


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© Springer Nature Singapore Pte Ltd. 2020

Authors and Affiliations

  1. 1.Faculty of Infrastructure EngineeringDalian University of TechnologyDalianChina

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