Evaluation of the effects of wastewater heat pump integration into district heating systems by simulation

The integration of wastewater heat pumps (using purified water) in district heating systems is analyzed in this paper. The simulation procedure is proposed to analyze the impacts of stochasticity of purified water temperature and flow to heat pump integration and operation. The analysis includes calculation of the daily and seasonal coefficient of performance, as well as fossil fuel savings and CO2 emission reduction due to wastewater heat pump use. The proposed procedure is implemented for the case study in the city of Sabac (Serbia) and obtained results are discussed and evaluated. The historical data for two heating seasons was used for simulation. It was shown that the wastewater heat pump could provide 27-28% savings in fuel consumption, and 3.6-4.1% GHG emissions reduction, while the seasonal COP could be 4.2 - 4.3. Simulation based approach shows approximately 40% less savings of fuel consumption, compared to the approach based on the average values of heat pump input parameters.