Energy and techno-economic assessment of the effect of the coupling between an air source heat pump and the storage tank for sanitary hot water production

Abstract

[EN] Heat pumps are proved to be a highly efficient technology for sanitary hot water production. However, when installing them coupled with the storage tank, an inefficiency up to 30% can be introduced in the system since this coupling cannot be direct according to EN 1717:2000; in order to prevent from any potential pollution of potable water in case of a refrigerant leakage. This research work evaluates three types of indirect coupling in the case of an air source heat pump system for sanitary hot water production: a coil heat exchanger inside the storage tank (CC), an intermediate heat exchanger between the tank and the heat pump (EHXC) and a double wall condenser (DWCC). A techno-economic assessment was carried out for the representative climate conditions around Europe. Results show that the DWCC is always the most efficient and cost-effective solution with a 3.66% lower energy efficiency than the direct coupling (Base Case), whereas the CC is not only the less efficient solution (27.1% lower than the Base Case) but also the less cost-effective, with a 50% lower net present value than the DWCC.