Thermal hardware-in-the-loop: concept, implementation, and experimental validation

As energy systems become more integrated, thermal equipment, alongside electrical equipment, plays a significant role in future energy grids. Therefore, there is a critical need for experimental platforms that allow flexible and accurate evaluation of thermal technologies. This paper presents a thermal hardware-in-the-loop (THIL) concept to provide a reliable framework for testing thermal sources and loads. THIL modeling of two case studies is implemented in MATLAB/Simulink and validated experimentally using a 15.6 kW heat exchanger and the OPAL-RT real-time simulator. In the THIL setup, a space heating load model is compiled on the real-time simulator and connected to an electric water heater via a heat exchanger, which serves as the thermal interface. The real-time simulation sends the heat exchanger fan speed as a forward path to the setup and receives the measured hot water supply temperature and flow rate as feedback. In both case studies, a step change in ambient temperature is considered in the load model to evaluate THIL response to a sudden and substantial change in thermal load, while in the first case, the flow rate in the space heating circuit is constant, and in the second case, it varies with the ambient temperature changes. ... mehrMeasurement uncertainties are calculated to support the reliability of the experimental results.