Theoretical Evaluation of District Heating and Cooling Networks Connected to Heat Pumps

This article conducts a comprehensive theoretical analysis containing operational, carbon footprint, and economic aspects of a medium-high temperature heat pump (HP) employing R-1234ze(E). The study contains a total of three scenarios, where the first (single stage/two stage (SS/TSC)) scenario uses waste heat for district heating. The second (SS/TSC) scenario produces heating and cooling for district heating and cooling. The third (TSC) scenario uses heat from the district heating network (DHN) for conventional boiler applications. Regarding the energy analysis, the internal heat exchanger (IHX) presents a positive impact across all scenarios. Moreover, the TSC configuration exhibits a lower coefficient of performance (COP) than SS for scenario 1, and higher for scenario 2. The first scenario (SS) results in the highest COP (4.1), due to presenting the lowest compression ratio among the three scenarios. From a carbon footprint perspective, compared to a natural gas boiler, the first scenario achieves the highest reduction in emissions. Regarding the economic analysis, TSC configurations exhibit higher costs than SS ones. The first (SS) and second (SS) scenarios present the lowest capital expenditure (CAPEX), 35134 € and 44371 €, respectively. Economic viability analysis reveals that only the first and second scenarios with SS configuration are feasible.