Bottom-up heat pump flexibility estimation for Swiss buildings considering monitored building data

With the continued uptake of electrical heating via heat pumps, residential heat pumps are expected to become a significant source of electrical load in future energy systems. Flexible operation of these systems has therefore attracted increasing interest as a means of mitigating peak demand and supporting power system operation. This work presents a bottom-up framework for estimating flexibility from residential heat pump loads using building thermal inertia and buffer thermal storages. The framework is designed to simulate flexible heat pump operation for arbitrary communities in Switzerland using primarily public data sources. The modelling approach is validated against three independent monitoring datasets, including measured building heat loss data, monitored building cooldown events, and a smart-meter-derived dataset of 243 residential heat pumps. These validations demonstrate that the framework captures the dominant thermal and operational dynamics of buildings and heat pumps at the community scale. Using the validated framework, we analyse the impact of different local demand-response strategies on aggregated heat pump loads, rebound effects, and indoor temperatures. Direct heat pump blocking achieves complete load reduction during short events but leads to pronounced rebound peaks and comfort violations during longer curtailments. In contrast, indoor temperature setpoint adjustment enables power reductions of up to 90% over four-hour windows at 0 ∘ C while maintaining thermal comfort and reducing rebound effects. Selective blocking strategies based on building characteristics provide a practical compromise, indicating that relatively simple control schemes can access substantial flexibility. Finally, the framework is used to quantify representative flexible power limits under varying weather conditions and times of day. Results indicate that downward flexibility generally exceeds upward flexibility, particularly in cold weather. Time of day has a more modest influence, although daytime solar gains reduce baseline heating demand and slightly increase available downward flexibility during midday periods.