Norwegian renewable energy provider Aneo Industry has partnered with agricultural cooperative Felleskjøpet to install an ammonia (R717) heat pump system at its animal feed production facility in Trondheim, Norway.
The heat pump system – provided by German OEM GEA and Norwegian evaporation technology company EPCON – uses 1.2MW (341TR) of waste heat recovered from the factory’s manufacturing process to produce 120°C (248°F) steam. The steam is then used in the production of the animal feed, reducing demand for the factory’s boiler system.
The case study was shared by Michael Bantle, CTO of Aneo, during his presentation in a heat pump case study session at the ATMOsphere (ATMO) Europe Summit 2023 on natural refrigerants. The conference took place September 19–20 in Brussels and was organized by ATMOsphere, publisher of Ammonia21.com.
Steam-producing heat pump
At the Felleskjøpet factory, the custom-built GEA heat pump provides 1.8MW (512TR) of usable heat in the form of steam and hot water.
“The cooling and drying process of the manufacturing line provides excess heat, which is transferred to a steam-producing heat pump,” he explained. “[The heat pump] produces 85°C [185°F] hot water and 120°C steam, the latter of which is then fed back into the production line.”
The first stage of the system consists of an energy recovery unit, which makes sure the energy in the moist and dusty air from the production line is transferred to the heat pump. The second element is GEA’s ammonia-based heat pump, which is a core part of the system, according to Bantle. It is here where the recovered energy is converted to 80–90°C (176–194°F) steam. The final step is a steam compression unit, which bring the steam up to the desired heat.
“With this set up we are quite flexible to have excess heat temperatures as low as 30°C [86°F] and can in theory deliver 150°C [302°F] steam,” he said.
The two-stage ammonia heat pump is made up of a conventional screw compressor for the first stage, and a piston compressor for the second stage, he added. To enable a more robust system with higher capacities, efficiencies and temperatures, the ammonia compressor includes new and more robust bearings, a condensation prevention system, a new oil distribution system and an ammonia droplet catcher.
“With this set up we are quite flexible to have excess heat temperatures as low as 30°C [86°F] and can in theory deliver 150°C [302°F] steam.”Michael Bantle, Aneo Industry
Felleskjøpet’s motivation for the project was driven by a number of factors, including enhanced energy efficiency, zero-emissions energy and cost savings.
The agricultural company wanted to identify best practices that it could then roll out across its six other production sites in Norway.
“It was very important for us and for the economy of the project that we have very high COP,” Bantle said. “Without good efficiencies, the project would not be viable from a cost perspective.”
With an energy requirement of 601.8kW, the system has a COP of roughly 3; however, Bantle noted that the efficiency of the system depends on the temperature lift.
Aneo faces penalties if the system, which should run for 20 years, doesn’t perform as designed, he added.
‘Investing in the future’
By choosing to invest in heat pumps, “we are basically investing in the future,” said Bantle during his presentation.
Thanks to their energy efficiency, heat pumps are much cheaper over their lifespan, compared to alternative heating systems like electric boilers or fossil fuel-based options, he explained.
“In terms of total cost of ownership, boilers are generally very cheap to buy but very expensive to run,” he said. “Conversely, heat pumps have higher capex investments but are much cheaper to run.”
He noted that this also makes end users much less exposed to external factors that drive energy prices.
To help overcome the higher upfront costs typically associated with heat pumps, Aneo offers its customers energy as a service (EaaS), which includes heat pump leasing. With EaaS, Aneo owns the service contract for the heat pump and is responsible for managing the risks related to system performance.
“With leasing, the project is profitable from day one,” Bantle explained. “Compare that to owning a heat pump, which has an ROI of more than four years.”
For the Felleskjøpet project, the heat pump is co-owned by Aneo and Felleskjøpet in equal parts.