For this demonstration site, 15 summer houses located in Jutland (Denmark) with annual power consumption of about 30.000 kWh per house have been selected. 

All the selected summer houses have swimming pools. Although the houses are not occupied throughout the year, they have a base heating load over the whole year to keep the pool water temperature, during unoccupied periods, above a minimum value, in order to allow customer to rent the house also with short notice.

These swimming pools can be used as thermal storage to provide flexibility to the grid.

These summer houses are rental accommodation provided for the project by NOVASOL.

Technology status quo

Each house is equipped with either a heat pump or a boiler. When the water temperature exceeds the upper value of the comfort band, a thermostatic actuator closes the valve regulating the flow of hot water from the heat pump to the pool, and no energy is provided until the water temperature drops below the lower bound of the comfort band. In this case, the actuator opens the valve and energy is provided until the upper bound is reached.


Two electricity grids will be tested with the objective to increase energy flexibility:

Deploy a price/CO2 based control

at the summer houses, which reacts to a price/CO2 signal to turn on/off the boiler.