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Abstract:

Global warming caused by anthropogenic greenhouse gas emission is expected to have long lasting effects on the environment, ecosystems and human society in the near future unless emissions are decreased. Electrifying residential heating loads through the use of heat pumps, can contribute to reducing residential greenhouse gas emissions. The addition of a dedicated thermal energy storage tank can provide additional flexibility to the electricity generation system which can be used to lower electricity generation related CO2 emissions. The main objective of this work is to assess the environmental impact of residential heating systems with heat pumps and hot water storage tanks in an electricity system with renewable energy sources. A life-cycle assessment of the heating system and a simplified electricity generation park was developed. To model the interaction of the set of buildings and the electricity system, an integrated model predictive control simulation was set up. Furthermore, a hot water storage tank model suitable for use in full year building simulations, including accurate representations of three-dimensional effects, such as inflow mixing and buoyancy, is developed and experimentally validated. Shifting residential heating from using gas boilers to heat pumps enables a significant reduction in CO2 emissions and total environmental impact, even if the heat pump controllers do not take the electricity system into account. The thermal inertia present in the building structure offers a significant amount of flexibility which can be used in a demand response context for load shifting and reduction of peak demand. Adding a hot water storage tank allows for a further reduction in environmental impact, however, this further reduction is less striking.