Danish district heating provider Solrød Fjernvarme has chosen a CO2 heat pump for an expansion project, making around 250 residential gas and oil boilers obsolete, and eliminating an estimated 1,200 metric tons of greenhouse gas emissions per year, according to Advansor and Solrød Fjernvarme.

Solrød Fjernvarme serves an area called Havdrup south of Copenhagen, which is experiencing increased population growth, and thus a need for more heating capacity. The company prioritized a high quality and high COP solution at a reasonable price, and settled on a SteelXL CO2 unit from Danish OEM Advansor, according to a post on Advansor’s website. The system was put into operation at the end of last year.

The heat pump system uses waste heat from a biogas plant, which is led through the heat pump, raising the temperature to the one needed. The system has a gas-fired boiler as backup when needed. The new system is also integrated with Solrød Fjernvarme’s existing system, which includes solar panels and an accumulation tank for the hot water.

The CO2 heat pump was installed in collaboration with Danish consultancy NatRef Engineering and contractor Aalborg CSP. The solution chosen by Solrød includes a SteelXL unit in a 6+4×0 configuration, with a 1.2MW capacity at +1ºC (341TR at 33.8°F). The system is equipped with parallel compression, permanent magnet motors, a high-efficiency oil separator, and an ultra-low superheat module.

“We have had good relations with Advansor for many years, and trust both the company and the products,” said Kristian Sørensen from NatRef Engineering. 

“Choosing a CO2 heat pump [for this district heating project] gives us value for money,” added Per Aasted from Aalborg CSP. “In addition, Advansor is a reliable and trustworthy partner who is easy to work with and who has shown great flexibility. Among others, the rack was divided into two for easier installation.”

In addition to the environmental benefits, Solrød Fjernvarme’s customers can also look forward to a financial one. With the current prices on gas and oil, the company estimates that customers switching from an oil boiler to district heating can save up to 40% in annual energy costs.

The system in Solrød is not the only Danish district heating project that Advansor is involved in at the moment. District heating providers in Rørvig and Frederiks are in the process of reducing their reliance on natural gas for heating by installing CO2 heat pump systems similar to the one in Solrød.

In Rørvig a new 1.5MW (426.5TR) air-to-water CO2 heat pump, supplying heat to 229 households, is expected to be up and running before next winter. In Fredriks, a project that includes two CO2 heat pumps of 1.5MW capacity each will produce heat and electricity.

The SteelXL

Advansor calls the SteelXL unit the “Tyrannosaurus Rex” of CO2 designs, and touts it as suitable for all system designs, including pumped, de-coupled with a chiller module, and DX. 

The patented SteelXL is customizable and in use in a wide variety of applications. In Belgium, retailer Delhaize is using it for supermarket cooling, and in Denmark, retailer Rema1000 is using it to cool a storage warehouse.

In Norway, Haukeland Hospital is using a SteelXL to run an air conditioning system. The hospital’s particular system was a SteelXL 8+2×0 configured parallel solution, which has a 2.6MW (739.3TR) capacity. It includes a chiller module, heat recovery and a gas cooler. 

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