Danish District Heating Provider Replaces Gas Boiler with Energy Efficient Ammonia Heat Pump

Danish district heating provider Saltum Fjernvarme has taken delivery of a an energy-efficient ammonia/NH₃ (R717) heat pump system with a coefficient of performance (COP) of more than three for its heating plant in Northern Jutland.

The integrated air-to-water DX heat pump solution was produced by Sabroe, and installed by Aalborg CSP in February 2021. The delivery was completed on time, despite the COVID-19 pandemic.

Saltum Fjernvarme’s new ammonia heat pump has a capacity of 1.2MW at 0°C (32°F), and is capable of producing 8,000MWh of energy annually, which is 80% of its customers’ consumption. The maximum temperature is 72°C (161.6°F).

Saltum has 370 customers connected to its network, and expects to cut around 70% of its annual CO₂ emissions with the new system, or 1,150 metric tons per year. Before installation of the ammonia heat pump, Saltum relied on a natural gas boiler, supplemented by an older solar thermal plant system.

Saltum chose the heat pump solution proposed by Aalborg CSP, after a tender, due to its high COP. The average annual COP for the system is above three, even at 0°C (32°F) ambient temperature, according to Aalborg CSP. 

“Aalborg CSP was selected as turnkey supplier of the system as our solution provided the client with the highest COP, and thus the lowest price per produced MWh,” said Per Aasted, Sales and Project Engineer at Aalborg CSP.

“We are happy that after a successful test phase it has been established that our plant delivers as promised. We know that it is not always the situation as heat pumps are relatively complicated pieces of machinery that includes high pressure, steam and liquids, which all have to be balanced,” Aasted added. “For that reason, I am extremely proud of the work that has been carried out.”

Despite a higher upfront cost, the efficiency of the solution chosen by Saltum Fjernvarme makes it a sensible investment for the utility provider.

“Our collaboration with Aalborg CSP has proceeded without any significant issues and minor bumps in the road have been resolved with a good result from both parties,” said Ole B. Hejlesen, Chairman of Saltum Fjernvarme.

“We hope that our consumers, in terms of the price on heat, will benefit from the solution we have made here in Saltum. At the same time, we are pleased to have chosen a green solution, which will help us reduce our CO₂ emissions.”