Danish renewable energy specialist Aalborg CSP have entered into a collaboration and contract for yet another heat pump project with the Danish utility company Envafors. The 10 MW air-to-water heat pump will use electricity from renewable energy sources, further enhancing the green and renewable district heating in Slagelse and its neighboring areas.

The interest in and need for large heat pumps for district heating production has been steadily increasing in recent years, and the technology seems to continue to have a solid foothold in the Danish district heating market. Electricity is becoming an increasingly important source for district heating production in Denmark, as the country is well on its way to phasing out coal, natural gas, and other fuels.

Envafors is among the Danish utility companies leading the way in the green transition. At Envafors, renewable energy accounts for approximately 85% of the heat production, which is produced using straw, wood chips, solar heat, and heat pumps. The new heat pump will enable the utility company to enhance and optimize the local green district heating supply, ensuring sufficient capacity to meet the needs of current and future customers.

The order is a turnkey project consisting of a 10 MW air-to-water heat pump with associated heat exchangers and pipes, as well as integration into the existing energy infrastructure. The heat pump system uses outdoor air as the source for heat production and is specifically tailored to fit the district heating plant’s specific energy needs and existing energy system to ensure the most cost-effective heat production price per produced MWh. The system consists of three separate heat pump units, each comprised of seven compressor modules and 12 energy absorbers. The overall heat pump system is highly flexible, which allows the operation to be adjusted to the plant's current needs.

Use of natural and climate-friendly refrigerant

The new heat pump system uses Propane and Isobutane as refrigerants, and these are, like ammonia and CO2, natural refrigerants.

While HFCs and HFOs have a Global Warming Potential (GWP) of approximately 2000,  Propane and Isobutane have a GWP of 3, which means they are significantly less harmful to the environment and climate.

Aalborg CSP and Envafors collaborates for the third time in a few years

The new heat pump facility in Slagelse will be Aalborg CSP's third green energy project in collaboration with Envafors. Last summer, the parties entered into a collaboration and contract for a 10.2 MW air-to-water ammonia heat pump system, which is currently under construction in Halsskov. Here, the heat pump system will be integrated with the local district heating plant's existing solar heating system and biomass boiler to achieve increased efficiency and flexibility. In 2019, Aalborg CSP also delivered a 11,733 m2 solar heating system with a capacity of 8 MW to SK Forsyning – now Envafors.

Project facts:

Client: Envafors
Capacity of the heat pump: 10 MW
System Supplier: Aalborg CSP A/S
Scope: Turnkey EPC contract including integration with the existing plant
Location: Slagelse, Denmark