Control strategies for heat pumps in a residential area under consideration of system operator benefits and grid stability

The energy sector faces challenges due to the increasing use of weather-depending renewables in power generation. The resulting fluctuations must be balanced through storage technologies and Demand Side Management (DSM) methods. Heat pumps are generally recognized as shiftable loads for DSM. More and more heat pump manufacturers in Germany are using the Smart-Grid- (SG-) Ready interface, which enables grid operators on the one hand and system operators on the other hand to control heat pumps for the purpose of DSM aiming at either grid power balancing (grid operator friendly) or to increase the self-consumption rate of the residential energy system (system operator friendly). The presented work aims at a compromise between those two goals. To this end, different control strategies for SG-Ready enabled solar and heat pump systems are implemented in a simulation framework and evaluated for a residential area using different key performance indicators. The results show that a control strategy based on a dynamic price signal ( PRBC2 ) with rule-based control and well-chosen switching points, taking into account considered building energy systems and environmental conditions used here, represents the best compromise between system operator friendly behavior and grid operator serviceability. The choice of switching points for the heat pump in the course of the price signal is crucial here. and must take into account the consumption and generation profiles of the local residential areas. The fulfillment value of the key indicators considered here for the representative residential area is 63.9%, whereas the value with the reference operating strategy, in which the heat pump is operated exclusively in SG-Ready Mode 2, is only 50.6%. • Modeling of Smart-Grid-Ready (SG-Ready) interface The SG-Ready interface is a simple interface that can be used to set the heat pumps to four different operation states. The implementation of these four states depends on the hot water storage tank temperature, where the set temperature is increased depending on the operation state. • Modeling of a Residential Reference Area (RRA) Within the framework of the IEA SHC Task 44 / HPP Annex 38 (A38T44), different reference building types have been defined and parameterized in order to guarantee uniform simulation heat loads. Taking this classification into consideration and based on the characteristics of HP market and the building stock in Germany an RRA of 1,000 houses has been developed. • Developing of control strategies using SG-Ready The SG-Ready control strategies will be differentiated into four groups: Self-consumption-optimized control, Standard Load Profile-based (SLP) control , Rule-Based Timer Control (RBTC) and Price and Rule-based control (PRBC) based on day-ahead electricity prices. The strategies in the first group have been described in the literature, the others are new contributions. • Evaluation of control strategies with consideration of grid operator serviceability and system operator friendly behavior In this article, a comprehensive evaluation of the effects of different operation strategies for heat pump systems was carried out. On the one hand, individual evaluations were carried out for single-family houses with different degrees of renovation and heat pump systems with and without photovoltaic battery storage systems and, on the other hand, for a representative residential area.