Limiting the rebound effects when utilising flexibility from heat pumps using an adaptive heat pump controller

Supporting power systems in severe power deficit conditions using flexibility from houses equipped with heat pumps is a powerful resilience action. However, the rebound effect of using flexibility has large negative cold load pick-up effects while restoring indoor temperatures to normal conditions. Even if the electric heaters in heat pumps are blocked, the standard heat pump controller will not operate fully desirable, leading to a large surplus rebound power consumption. The contribution of this article lies in proposing an adaptive heat pump controller to limit this effect. The proposed controller provides estimates of water supply temperatures to deliver maximum heat at various indoor temperatures during indoor temperature recovery. The Swedish power system with a maximum consumption of 20–25 GW is used as a reference case. Here, at −5 °C outside temperature, approximately 1.9 GW is required to maintain indoor temperatures around 20 °C, in 44% of single-family houses. The power system can be relieved of 1.9 GW for 7 h and 650 MW for the next 10 h, with the consequence that the indoor temperatures drop to 15 °C. During the indoor temperature recovery to 20 °C, which takes 20 h, using the proposed controller, the maximum rebound power is limited to 2.6 GW compared to 3.9 GW using the standard controller. Thus, achieving a 33% reduction in peak power. • Flexibility from houses equipped with heat pumps to support grid with power shortages. • The consequence of offering flexibility is reduction in indoor temperature. • Rebound effect of flexibility is surplus power use during temperature recovery. • To limit rebound effects an adaptive heat pump controller is proposed. • The proposed controller results in 33% peak power reduction during recovery period.