Abstract: Heat pumps are very important for improving the energy efficiency
of heating, cooling, and hot water generation, but also for increasing the utilization of renewable energy and low-temperature heat sources. The design and optimization of energy systems with heat pumps might lead to better results in
terms of their energy efficiency and cost attractiveness. This paper extends a
previous research and analyzes primary energy consumption of a hybrid heating
system that consists of heat pumps, heat storage, and a connection to the district
heating network. It assumes that the system is running in a cost-optimal operating regime and considers four cases of electricity pricing: (1) flat tariff, (2)
time-of-use tariff, (3) progressive tariff, and (4) combination of time-of-use and
progressive tariff. The cost-optimal operation regimes are obtained with mixed
integer linear programming. The results indicate that the primary energy consumption considerably depends on the electricity pricing scheme, mainly because the time-of-use tariffs offer electricity for very low prices, but also because progressive tariffs might limit the application of a heat pump with high
electricity prices in the most expensive tier. It is also important that the increase
in the price of district heat makes heat pumps more attractive and contributes to
the primary energy reduction, under the examined set of conditions.