Stella Polaris, Norway: Mayekawa ammonia–pentane cascade for cooker steam
IEA HPT / SPIRIT demo card (installation year 2025): a Mayekawa cascade of about 0.8 MW at the Stella Polaris shrimp plant in Finnsnes upgrades refrigeration reject heat to steam near 145–150°C. Design COPs are published; this site has not metered the plant.
Engineering data
- Case type
- Public-source case
- Data status
- public_source
- Industry
- Food
- Source temperature
- 7–18°C
- Sink temperature
- 145–150°C
- Temperature lift
- ≈ 127 K
- Heating or cooling duty
- 800 kW
- Architecture
- Oil-lubricated screw/screw cascade: ammonia lifts refrigeration heat to about 82°C, pentane then produces steam
- Result status
- The IEA card lists installation year 2025 and design heating COP 1.8, combined COP 2.5. A 2024 SPIRIT slide had scheduled commissioning for August 2024; this entry follows the later card and does not treat the earlier schedule as a measured operating record.
- Key risk
- Steam pressure differs slightly between the 2024 slide (3.2 bar) and the 2025 card (4 bar(a)). Operating hours on the card are marked n/a. Design COP is not a measured seasonal result.
- Existing system
- Propane-fired steam boiler for shrimp cooking; refrigeration plant rejecting heat near 18°C
- Refrigerant
- Ammonia (bottom) and pentane (top)
- COP
- 1.8–2.5
- Annual savings
- IEA card: estimated about 621 t/a CO₂ versus the propane boiler; investment listed as €0.8 million excluding integration
- Estimated payback
- Not stated as a verified payback in the card used here
Project background
Stella Polaris in Finnsnes, Norway, cooks and peels cold-water shrimp. The EU SPIRIT project and Mayekawa published a cascade heat pump that replaces the propane steam boiler for the cooker. This is a public food-industry steam case, distinct from this site's anonymized meat-plant hot-water surveys.
Narrative inputs
Source: refrigeration reject heat, card boundary about 12°C to 7°C. Sink: steam about 145–150°C. Heating capacity about 0.8 MW (earlier material also cites 715–717 kW).
Heat pump solution
An ammonia screw heat pump and a pentane screw heat pump are coupled by a cascade heat exchanger. The pentane stage produces saturated steam for the prawn cooker. Both compressors are described as oil-lubricated screws adapted for the duty.
COP & savings
Design COP of heating is 1.8 and combined COP is 2.5 on the IEA card. Estimated CO₂ savings are about 621 t/a. Operating hours are not filled in. The 0.8–2.5 COP range on the card is therefore a design pair, not a measured band.
Investment / ROI notes
The card lists investment of €0.8 million excluding integration. It does not publish a payback. Savings in euro per year are left blank on the card.