CO2 Emission Reduction Potential of Bivalent Heat Pump Systems

Abstract

The use of heat pumps is beneficial. By this, the share of fossil fuels in the energy mix and CO₂ emissions can be reduced. However, these effects highly depend on the type of the auxiliary energy used and the parameters of the heat pump system, including using monovalent or bivalent modes. For a certain building with a given heat demand, the achievable CO₂ savings compared to gas firing have been determined for three different operating modes, three different types of auxiliary energy and three different specific CO₂ emission values from electricity generation.
The reduction in CO₂ emissions associated with heat pump operation ranges widely. When operating in bivalent mode (bivalence point: 2 °C), the values are less favourable and several of the variants tested do not show emission reductions, especially when operating in alternative mode. However, the reduction of fossil CO₂ emissions in bivalent systems using biomass as a source of renewable energy and geothermal heat pumps is high (up to 56.7% for the Hungarian electricity mix), which is very similar to the reduction of carbon dioxide emissions in monovalent systems (54.1%).