The greenhouse was built and put into operation in 2007. It has a total floor area of 3,000 m2. Half of the area is used for plant production. The rest of the area consists of a construction hall, intended for the landscape gardeners, as well as common rooms such as changing rooms, sanitary facilities, classrooms and a separate processing room.
Here, tomatoes are grown on 1/3 of the area. There are an average of 1.5 sets of new plants each year, and the plants that are set out are raised in the greenhouse. Tomato production is now 70 tons per year. The rest of the area used for cultivation is used for flower production.
Energy consumption
There is an annual consumption of electricity of 1.1 GWh (1.1 million kWh). Tomato production in particular is dependent on a lot of light all year round. Furthermore, about 800,000 kWh of heat energy is used per year to keep production in the greenhouse running. Most of this energy comes from the heat storage installed in the greenhouse.
How does the thermal storage work?
An advanced system has been built in the greenhouse to store heat energy created by solar heat and light in the greenhouse. Aerotherms have been installed on the roof of the greenhouse, which, through cooling and dehumidifying the air, make it possible to store excess energy. The energy is stored underground in a large water tank (short-term storage). When the water in this storage has reached a certain temperature, the heat is conducted further down into deep boreholes outside the greenhouse (long-term storage). There are a total of 44 boreholes in which the heat energy can be stored. The heat is extracted during the cold season, and the effect is increased by using heat pumps. The heat storage provides a net delivery of just over 900,000 kWh of heat energy annually. The use of propane for heating has decreased significantly since the heat storage was put into use. The heat from the heat storage is used to heat the greenhouse, as well as classrooms, offices and other common rooms at the school. Heat pipes have been laid in the ground to transport the heat around the school grounds.
The heat storage system was developed by researchers at Gether AS in collaboration with Trøndelag County Council, SINTEF, Kværner and the school.
