For space heating, a simple PI control strategy is used to obtain the prescribed setpoint. To avoid overheating, if the temperature at 6:00 a. m. exceeds the setpoint, the theatre curtains are moved to a position depending on the radiation expected for the current day. In order to incorporate predictive control, the design of control strategies has been based on a simple control strategy: both the tank temperature setpoint (active storage) and the operative temperature (an indicator of the status of passive storage) depend on current conditions and the solar irradiance expected for the following day. Some results of applying this control strategy are shown below.

It has been found that heating can be provided over the 2 cloudy days following the first three sunny days without using the ground source heat pump. It has also been found that the PV generation exceeds the power consumption of the heat pumps. As no additional electric power is needed for the grid, this has interesting implications for load management. As expected, the heat pumps consume more energy as the tank gets hotter. This is one factor that should be considered in the design of the control strategy. It has been calculated that over these 5 days, the heat pumps consumed approximately 61 kWh for heating the house. The total yearly electric energy consumption of the house has been calculated to be about 7100 kWh, of which 2500 kWh is consumed by the HPs. The PV panels generate 8600 kWh. The remaining energy (1500 kWh) is intended to be used for the plug-in hybrid car.