Hardware in the loop test bench using Modelica: A platform to test and improve the control of heating systems

HVAC manufacturers make important investments to develop more efficient technologies for space heating (SH) and domestic hot water generation (DHW). Among these technologies, this article focuses on Double service air-to-water-heat-pumps (AWHP). The control of AWHP strongly impacts their performances, so that manufacturers of AWHP need to optimize the control of their systems to increase their performances. This paper presents the implementation of a Hardware-In-the-Loop - HIL - real time simulation test bench for AWHP. The new test bench proposed uses real weather conditions and simulates building's and occupants' response thanks to a virtual model. This test bench allows R&D departments and manufacturers to test several heating systems in parallel as well as different control options. It may also limit the need for field testing. It thus has the potential to reduce the cost and time required for AWHP development-to-market process. The test bench presented in this paper is used for a specific AWHP and a typical building in France. The analysis of the impact of the heat pump's control on the system dynamics and on the indoor thermal comfort enables to highlight control issues related to the heating curve, the DHW management and the defrost process of AWHP. Optimized control parameters throughout time are proposed in view of reaching lower consumption and better performances. This case study shows the potential of the HIL test benches for manufacturers to optimize the development of their products controls.