Innovation provider

SEEC – Scandinavian Energy Efficiency Co ,


Andreas Andersson
Phone. +468 7548301


The SEEC Energy Store Saves Summer Heat for Winter

Energy prices rise and emission of greenhouse gases must be reduced. Everyone tries to reduce their energy consumption and science leaves no stone unturned in their search of environmentally friendly ways to produce energy.

With the SEEC Energy Store you can save the summer heat and use it during the winter. By storing energy instead of producing it anew, both energy consumption and emission of greenhouse gases can be reduced substantially.
Coal, oil, hydroelectric- and nuclear power have long supplied us with affordable energy. Today, energy prices increase rapidly. The price of oil has multiplied in less than a decade. Ever increasing prices force us to reduce our energy consumption and we also have to consider the environmental effects. Emission of greenhouse gases contribute to global warming, an effect that can no longer be ignored. The European Union requires that emission of greenhouse gases must be reduced by 20 % by 2020. New estimates suggest that emissions need to be reduced by 70-85 % by 2050 to limit global warming.

Rising costs and emission reduction requirements force us to reduce energy consumption
Emission reduction work is mainly carried out in two areas, reducing the need for energy and developing environmentally friendly energy production. Sun, wind, waves and tidal currents are some areas that are being looked into.

Up to 45 % of the energy is used for heating, ventilation and cooling of properties. Cooling gets more common, also in residential areas, and uses increasing amounts of energy. Summertime there is excess heat and we use energy for cooling, wintertime there is a heat deficit and we use energy for heating.
SEEC has solutions for surfaces from 2 000 m2.

With the SEEC Energy Store and Energy Modules we can save the excess heat from the summer and use it for heating during the winter!


SEEC’s five so called Energy Store Principles

Containing the energy in the energy stores has been a big problem and the losses have been substantial. After extensive development, SEEC has found solutions to this problem and has refined the technology in a number of points, SEEC’s five so called Energy Store Principles:
1. Balanced Energy Store
The temperature in the store is varied around the natural ground temperature. In summer, it rises to around 3 degrees above the natural ground temperature and in winter to around 3 degrees below. Thus, if the natural ground temperature is 8 degrees, the temperature in the store will vary between 5 and 11 degrees. In winter, heat pumps are used to raise the temperature sufficiently for heating the building. Summertime, the temperature is sufficient for cooling directly, without using heat pumps.

2. Low Temperature System
The energy gain of a heat pump is referred to as Coefficient of Performance, COP. If a heat pump uses 1 kWh electrical energy and COP=4, it will give off 4 kWh of heat energy. By using large surface radiators for heating, the energy saving is maximized. The temperature of the water used for heating can be lowered. The smaller the temperature increase required from the heat pumps, the higher the COP, leading to further energy savings. In the corresponding way, the water used for cooling should have as high temperature as possible to maximize the energy saving. In modern buildings, 30 degrees can be used for heating and 14-16 degrees for cooling.

3. Intelligent charge and discharge of energy
Summertime the store is heated. The heating starts in the centre and progresses towards the periphery. In this way, a heat wave moves from the centre and outwards. If the store has been properly dimensioned and is heated the right way, the heat wave will reach the periphery when it is time to start heating the building. Energy is now discharged in the opposite direction, from the periphery towards the centre. Charging and discharging energy this way minimizes the losses from the store.
4. Cost Effective Energy Balancing
For an energy store to work optimally, the energy discharged over a year must balance the energy charged. If the waste heat from the summer cooling does not correspond to the heating need of the winter, the store will be out of balance. SEEC solves this problem in a cost effective way by using collectors. These are used summertime if the store needs additional heating and in the winter if it needs cooling. Using collectors, very large amounts of energy can be charged or discharged at very low costs.

5. Intelligent Management and Control Using Open Standard
The temperature of the boreholes is measured to manage and control the store. Charge and discharge of energy is controlled for the boreholes according to season and the building’s need for heating or cooling. The store’s total energy is computed continuously. Management and control of the store is integrated with management and control of heat pumps and peripherals. The management and control systems are based on open standards, e.g. Linux, and can be controlled remotely over the Internet. The SEEC Energy Store uses a number of newly developed methods for management and control of energy stores.
With the SEEC Energy Store and Energy Modules you get the energy solution of the future today!

About Energy Stores

The development of energy stores gained momentum during the seventies. Since then, interest from authorities and property owners has varied in pace with changes in energy prices. The energy stores that have been built have mainly been for research and development.

Since mid nineties, investments in heat pumps that draw energy from air, ground or mountain has become profitable. As a result, today there are more than 1 000 000 installations world wide. Around one forth of these are to be found in Sweden. Since heat pump technology makes up a central part of energy stores, these have also become profitable.

An energy store can be described as a series of concentric boreholes. The number of boreholes and their required depth depends on how much energy needs to be stored, which in turn depends on how much energy is needed for heating in the winter.
Cooling produces waste heat. Normally, the waste heat is dispersed through fans on the outside of the building. With the SEEC Energy Store the waste heat is used to heat the ground that surrounds the boreholes. If the need for cooling is big, the energy from the waste heat is usually sufficient for the winter heating. If not, collectors can be used. Collectors are fluid filled pipes that are dug into the ground, so called ground collectors, or other types of collectors, e.g. air collectors. As the sun heats the ground, the fluid in the collectors is heated. This heat is used to further heat the ground around the boreholes.
By end of summer the ground around the boreholes has been warmed up. During winter, energy is led from the store through heat pumps to the heating system of the building. If the store has been properly dimensioned, no more energy is needed to heat the building.

The example above describes how an energy store can be used in a Northern European type of climate. In warmer climates, such as Southern Europe, the store can be used in the reversed fashion, to save the cold of the winter and use for cooling in the summer

Innovative aspects (ecologic, social and economic)

The environmental benefit of SEEC’s offer is the reduced energy need for heating and cooling. “Free” energy, in the form of excess heat during hot periods of the year, is used instead of fossil resources, which contribute to global warming. The customers who choose to install energy stores are accordingly reducing their costs for heating and cooling substantially, and in addition their environmental image is improved. For a large building the energy need for heating and cooling can be reduced by 70-80 percent.

Application examples



Current stage of development

Exported to other countries 

Intellectual Property Rights

Patent granted

Country of origin


Country of application



National Contact Point

Uwe Fortkamp
IVL Svenska Miljöinstitutet AB
Valhallavägen 81
P.O. Box 210 60
114 27 Stockholm

Tel: +46 8 598 56300
Tel: +46 8 598 56390