Italian compressor manufacturer Frascold and Solid Energy, a Danish cleantech company focusing on sustainable district heating solutions, have joined forces to promote the use of hydrocarbon heat pumps in district heating systems in Denmark.

The Nordic country has one of the most widespread district heating networks in the world, with around 65% of all homes being connected to one and 72% of all energy used in the sector comes from renewable sources.

Solid Energy develops heat pumps powered by renewable energy sources and Frascold manufactures compressors for natural refrigerants like hydrocarbons, including screw and reciprocating models. The heat pumps from Solid Energy are available in capacity ranges from 150kW up to 2,500kW. They can use heat sources like waste heat, sea water, river water, ground water and plain old air.

“We think HC [hydrocarbon] heat pumps are ideal for helping reduce the comfort sector’s environmental impact,” said Karsten Pedersen, Technical Director at Solid Energy. “Cascade systems with R290 [propane] and R600a [isobutane] guarantee the best balance of lowering direct and indirect consumption, flexibility of use, and costs.”

A recent example of the collaboration is an upgrade to a district heating system in Galten, just west of Aarhus, the second largest city in Denmark. The original system has been in operation since 1964, heating around 2,130 homes. 

In 2019, Solid Energy began developing a heat pump system for Galten capable of delivering 45,000MWh per year. The system was built with six Frascold CXH hydrocarbon screw compressors with a combined capacity of 3.5MW. In 2021, the system was further expanded with an additional 7MW of capacity, also using the CXH compressors.

The hydrocarbon air-to-water heat pumps have 34 air coolers and cover 98% of the Galten district heating system’s power consumption, with a SCOP (Seasonal Coefficient of Performance) of 3.11. The plant provides a discharge temperature of 70°C with a return temperature of 38°C. This gives the system a COP of 3.4 at an ambient air temperature of 8°C, which is the annual average in Denmark.

“So for this project, we relied, once more, on Frascold, which has supported us throughout each phase,” Pedersen said. “The partnership with Frascold is also based on the certified reliability of its wide range of hydrocarbon solutions: it is, in fact, the only manufacturer on the market with compressor sizes around 1,000 m3/h, which are perfect for our project and comply with ATEX directives for use in zone 2.”

“Denmark is one of the most advanced countries in terms of district heating,” said Fabrizio Diotallevi, Frascold Sales Area Manager in Northern Europe. “With the numerous plants brought online by Solid Energy, we are proud to contribute to this ambitious project, which we hope will be replicated in other countries.” 

“This new success story with Solid Energy is another example of our expertise in building heat pump compressors, which we have gained through years of international partnerships using this technology that, in the near future, will be the basis for virtuous heating and zero environmental impact,” Diotallevi concluded.

“Cascade systems with R290 and R600a guarantee the best balance of lowering direct and indirect consumption, flexibility of use, and costs.”

Karsten Pedersen, Solid Energy

Want to find out more, or have something to say about this story? Join the ATMO Connect network to meet and engage with like-minded stakeholders in the clean cooling and natural refrigerant arena.