Copenhagen markets

The nordics’ largest refrigerator offers reduced district energy bills. This perspective is written by Uffe Schleiss, Technical director, District Heating Høje Taastrup.

By State of Green | [email protected]

1 April 2020

Flowers, fruit and vegetables are kept fresh in the Nordic countries’ largest and most advanced refrigerator in Høje Taastrup, while simultaneously providing green, inexpensive district heating to its neighbours.

At the old market square, each business owner had their own cooling systems, with varying levels of efficiency. In the new 67,000 m2 Copenhagen Markets, which opened in Høje Taastrup in April 2016, a 15,000 m2 cooling area has been established, which is supplied by a large, joint district cooling plant. This system is the most comprehensive of its kind in the Nordic countries and has a number of positive impacts on energy consumption, the climate and the working environment.

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Although the name of the company providing energy to Copenhagen Markets is HøjeTaastrup District Heating, it actually provides district cooling as well. The cooling is delivered from a newly installed electricity and ammonia powered cooling compressor. A heat pump utilises the energy from the
cooling process to create green, inexpensive district energy. It is necessary to deliver water at a temperature of between 2 and 5 °C to the customers
at Copenhagen Markets. This requires that the water is chilled to a temperature of minus 8 °C. District Cooling is normally delivered with a flow of 6 °C and a return flow of 16 °C. To meet Copenhagen Markets’ requirements, an extra chiller has been installed.

Production of the cooling means that considerable amounts of heat are also generated in the process. An electricitypowered heat pump upgrades the heat and sends water to the nearby district heating system with a temperature of 73 °C, which is a satisfactory flow temperature. The system is a co-production of chill and heat, where the one product cannot be produced without the other. There is a cooling capacity of 2 MW. Heat corresponding to 2.3 MW is produced at a water temperature at 73 °C. This constitutes approximately 2.5% of the overall heating consumption to Høje Taastrup District Heating’s 6,700 customers and is yet another example that systems thinking and utilisation of resources are of the utmost priority.

The cooling system at Copenhagen Markets is designed so that the cooling can be used at different levels according to need. The markets are divided into 80 tenancies under the one roof, whereof 55 use cooling. Each tenant has the option of using cooling and deciding exactly where in their area the cooling should be delivered is needed. Consumption is calculated individually via an innovative meter solution. The capacity for cooling can be increased as the need develops over time.