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For the first time ever, a football pitch with synthetic turf will be heated with surplus heat generated by the coolant compressors for an artificial ice bandy pitch. This achieved by storing the heat from the compressors in a thermal energy storage unit.

When needed, the heat is transferred through a heat exchanger to heating pipes under the football pitch. In this way it is possible to play all year round on the pitch. Not only the environment is a winner with this plant, the running costs over a 40 year period will only be a third compared to the costs for district heating. These pitches are situated at the Duveholm sports field in Katrineholm, and the technology that makes this possible was supplied by Scandinavian Energy Efficiency Co.  SEEC AB.

A thermal energy storage unit can be simply described as a number of wells drilled in concentric rings. Thermal energy storage is in itself not something new, development gained pace during the 1970-ies, but SEEC has after considerable development work refined the technique in a number of areas. SEEC not only supplies the thermal energy storage, but also an energy module with two heat exchangers and ancillaries as well as equipment for control and surveillance of the entire plant.

When the compressors of the artificial ice plant are working they generate heat. Until now this heat was vented into the air using fans, since the temperature is too low to be used for the heating of houses, for example. The plant that SEEC is supplying Duveholm sports field will connect the compressors to the thermal energy storage, since the temperature is high enough for that purpose.

At the same time that a new pitch with synthetic turf is constructed, heat pipes are laid under the turf. The heat exchangers in the energy module connect the thermal energy storage to the heat pipes. The energy module controls the temperature of the football pitch, and when the pitch needs heating, the heat exchangers are started and they feed the heat pipes with energy from the thermal energy storage. In this way it is possible to play all year round on the pitch.

Sunny days will heat the heat pipes enough to add heat to the thermal energy storage, without needing the heat exchangers. The heat from the bandy pitch gives enough energy to heat the football pitch, but adding energy from the heat pipes in summertime will increase the temperature in the thermal energy storage.

In this way the thermal efficiency and economy is further improved. By using a thermal energy storage with an energy module from SEEC, the Katrineholm County Council will reduce the amount of energy they use compared with conventional heating - for example with district heating – and they will at the same time minimize the environmental impact.

With SEEC technology, environmentally friendly technology is cheaper than conventional heating. According to the Katrineholm County Council, the running costs with district heating would be SEK 45 million over a period of 40 years. With SEEC technology, the cost for the same period will be SEK 15 million, including depreciation.

The energy consumption for the Backavallen sports field compared to a reference sports field

The energy consumption for heating the Backavallen synthetic turf has been monitored on a daily basis since the unit was brought online November 1, 2008.

The measurements show that since then, the energy consumption has been considerably lower than calculated, even though the average ambient temperature has been below zero degrees centigrade.  The unit has managed its duty even though there have been periods of severe cold.

The total energy consumption up to February 15 was about 100 MWh. It is estimated that the energy consumption up until the end of winter will be about 150 MWh including that needed to run the pumps for the liquids.

Besides the direct savings, there is a further reduction in energy consumption at Backavallen, caused by improving the condensing temperature for the coolant compressors.

A conventionally heated plant of the same size has been used as reference plan during this period. Calculations for the whole winter period, show that the reference plant will consume 1700 MWh

In summary, the first winter, a saving corresponding to between SEK 1.5 and 2 million compared to the reference plant is achieved.

Sigtuna Steningehöjden – where the environment heats the houses

North of Stockholm, in Sigtuna municipality, a new district is being built with a total of 900 houses, half of which are villas and half are multiple units, and these are heated using renewable resources. Peab is building these houses, with heating systems which use a minimal amount of energy. These houses are expected to be ready within a ten-year period.

Ground-source heating, i.e. drilled holes in the ground with heat exchangers, is a technique for heating houses that is frequently used and well-known in Sweden, having been used in more than 350 000 units. For larger houses, shopping malls, hotels etc., thermal energy storage is used.

A thermal energy storage unit can be simply described as a number of wells drilled in concentric rings connected to a heat exchanger (collector). Thermal energy storage is in itself not something new, development gained pace during the 1970-ies, but SEEC has after considerable development work refined the technique in a number of areas. SEEC not only supplies the thermal energy storage, but also an energy module with heat exchangers and ancillaries as well as equipment for control and surveillance of the entire plant, using Internet.

Multiple unit housing with low energy consumption in Steningehöjden

Heated area 2500 m2 (well insulated)
32 apartments 

Annual consumption for heating, including hot water (kWh/m2, year) 
 
Normal energy consumtion     
63 kWh/m2, year (oil, electricity or, district heating)

With SEEC solution
16.5 kWh/m2 electricity   (46.5 ground storage (renewable)

The SEEC patented energy solution – with a well-balanced thermal energy storage drilled in concentric rings – was chosen as the most advantageous heating solution, both economically and environmentally. If there is any change in the price of electricity, the heating cost for a house with the SEEC solution will only change with about 25% (since 75% is coming from the ground source heating). If you use oil or district heating, a change in price will have a 100% impact.

The design of the thermal energy storage – which is recharged/balanced with renewable energy – will only need limited area that may also be used for other purposes, such as parking, roads, and gardens.