Fjärrkylanät City

The district cooling in the City grid is produced with three different techniques:

- Absorption cooling, left over heat from the district heating production is used

- Free cooling, the river Stångån or the cold air is used 

- Compressor cooling, where electricity is used

The choice between the production techniques is determined by the economics and the cooling needs. 

District heating used for absorption cooling is distributed straight from the district heating network. Therefore, the heat will be produced with the same fuel mix as the rest of the district heating at that moment. Due to economic reasons related to the costs for the fuel, it’s not economically feasible to use absorption cooling during the coolest period of the year. Hence the absorption cooling technique is mainly used during the warmer months, which, in many cases, is when the cooling demand is largest. 

Free cooling will basically always be a cheap alternative. However, the water or air that is used must be cold enough, which will only be the case during the cooler period of the year. The cost and green house impact of the compressor cooling is depending directly on the same properties of the electricity in the grid at that moment. In the compressor cooling the used refrigerant is ammonia whose global warming potential is very low (GWP=0).