The project aim was to demonstrate that space heating by means of solar energy and aquifer storage is technically feasible and capable of primary energy savings +/- 50%. The project was built in Bunnik for the company Bredero. The office building to be heated consisted in three units of 9,000 m² total floor surface with an annual heat demand of 660 MWh. The building was not equipped with a cooling system except for the computer room.
The heating system contained: flat plate solar collectors, short term energy storage, long term thermal energy aquifer storage (with an estimated injection and extraction of about 18,000 m³), a gas engine driven heat pump and a conventional gas boiler. For space heating, the waste heat of the computer room cooling system was used (95 MWh/yr). The annual gas consumption of the heating system was estimated to be 392 MWh. There were three operating modes of the plant:
Summer: heat from the collectors and the computer cooling system is injected into the Aquifer

Spring/Autumn: space heating by a heat pump with heat supply from solar collectors and cooling system waste heat

Winter: space heating by heat pumps with heat supply from an aquifer and a cooling system and additional heating by a gas boiler at low outside temperatures. The solar system is not in operation in the wintertime.