FENhouse: Heat pump and machine room in one

Hanstholm District Heating Utility has shifted its energy mix from 70/30 in favour of biomass to 70% electricity-based heat production - with two CO2 air-source heat pumps. Each heat pump is installed in a FENhouse
enclosure, delivered to site as a fully approved machine room.

The Case

Over three years, heat demand in Hanstholm increased by a third, driven mainly by new industrial customers in the
fish processing and aquaculture sectors, where production processes and sanitation require supply temperatures of up to 80°C.

To meet rising demand and support its ambition to participate in the balancing market, the utility needed to expand
production capacity while maintaining operational flexibility. A CO₂ heat pump solution was the natural choice, thanks to its ability to deliver temperatures of up to 85°C and its rapid start-stop capability for grid-support services.

Today, Hanstholm supplies heat to households and industry while also providing flexibility to the regional electricity grid.

FENhouse

  • Fully approved machine room

  • Heat pump, piping, defrost module
    and controls

  • Lighting, ventilation, CO2 alarm and
    sound dampening

  • Easy service access

  • Cost-effective and time-saving

  • Modular and scalable

  • Multiple design options

Year: 2024

Model: 2 x H-2600 in FENhouses

Application: Air-to-water heat pumps

Capacity (heat):
5.2 MW (5°C ambient, 42/75°C hot water)

COP: 3.0

Defrost method: Glycol

Hot water storage: 10,000 m3

aFRR operation: 5 minutes start/stop

The walkway by the evaporators provides easy service access.

Optimised energy collectors and FENdefrost

Next to the FENhouses are 12 next-generation Güntner evaporators acting as energy collectors and capturing ambient energy year-round. Each energy collector is equipped with 14 fans and can deliver up to 300 kW.

Fenagy’s advanced control system, FENcontrol, and glycol-based defrost circuit, FENdefrost - tested and refined over five winters - help maintain high output and operational reliability throughout the Danish winter.

Heat pumps in enclosures

Hanstholm’s solution features two H-2600 air-to-water heat pumps, each housed in a FENhouse enclosure. The FENhouse setup made the project fast and straightforward, with only 6 months from order to first heat delivery and no need for a new building. A new building would have taken much longer to approve and forced Hanstholm to rely on more expensive production units in the meantime. The fast-track process therefore meant significant cost savings.

A FENhouse is fully prepared for plug-and-play integration with energy collectors and the local district heating grid when delivered on site. Each enclosure is designed with easy service access, integrated lighting and ventilation - and complete with piping, defrost module and control systems.

Together, the two units deliver 5.2 MW of fossil-free heating capacity at temperatures of up to 85°C. This supplies heat to the town’s 1,100 households and meets the needs of local industry, where high-temperature hot water is required for processing and cleaning.

The heat pump installation is part of a new production mix, which also includes a 10 MW electric boiler, two large accumulation tanks (10,000 m³ total) and a 6.3 MW woodchip boiler. Gas engines remain available for emergency operation and market participation.

The FENdefrost system ensures reliable operation of the evaporators even in snow and frosty weather.

H-RANGE
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