Journal of Water Reuse and Desalination (Sep 2019)

A study on the design and analysis of a gas engine heat pump water heater using shower wastewater as heat source

  • Fengguo Liu,
  • Zhenxi Ma,
  • Rui Zhang

DOI
https://doi.org/10.2166/wrd.2019.002
Journal volume & issue
Vol. 9, no. 3
pp. 310 – 318

Abstract

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Shower wastewater contains large amounts of heat, and recovering and utilizing shower wastewater heat energy to heat shower water is of great significance for energy saving. This paper proposed a gas engine heat pump water heater (GEHPWH) using shower wastewater as the heat source. Thermodynamic models were built to evaluate the performance of the GEHPWH and compare it with an electrical heat pump water heater (EHPWH). The results show that the GEHPWH has higher hot water outlet temperature and coefficient of performance (COP) than the EHPWH under the same conditions. Furthermore, the GEHPWH can maintain stable hot water outlet temperature and higher primary energy ratio (PER) in variable water flow mode, which resolves the issue that the conventional EHPWH needs an auxiliary heat source. Finally, based on a case, the GEHPWH reveals smaller energy consumption and lower operating costs compared with three other conventional hot-water schemes.

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