The heat pump system planning bottleneck: what data you need for optimal planning and what is accessible
A major obstacle to the use of heat pumps in existing buildings is the complex planning process involving the risk that heat pumps may not be able to reach high flow temperatures. In the literature, there are several approaches, identifying the optimal design of a heat pump system for existing buildings. However, input data for optimal design studies differs from real-world available data. This work gives insights into the planning process of heat pump system for existing buildings from both perspectives: Optimal planning with perfect input data in science and best possible planning based on available data in practice. The data analysis captures: (1) general information (e.g., location, behaviour of residents, past energy bills, past modernization, planned modernization), (2) building and weather data, (3) building heat demand calculation, (4) information about the heat transfer system, (5) system integration data (storage, back-up heater, installation site), and (6) heat pump data. The comparison shows that available data in practice is insufficient for optimal planning and even critical for near-optimal planning. The gap between optimal and near-optimal planning can be reduced step by step with just a little additional information. However, today, the additional information is not available in practice and planners must assume data or base their planning either on work experience or on over dimensioning the system. Both ways are not standardized and yield that the heat pump system design for a single building differs based on the planner. Different planning results can confuse end customers, as it is not clear which planned system is best for them. It is therefore necessary to further harmonize the planning process and provide further training for planners, installers, and end customers so that heat pumps can be integrated into existing buildings in a sensible manner.