ALWERA AG, an Austrian agricultural company headquartered in Styria and specializing in the production, processing, and marketing of agricultural products – including seed corn, oil pumpkins, and Styrian scarlet runner beans – has fundamentally redesigned the heat and cooling supply at its Wollsdorf production site as part of its “Energiewende” initiative.
The project was supported under the Austrian environmental funding scheme ‘Innerbetriebliche Energiezentrale – Zentrale Waerme- und Kaelteversorgung fuer Trocknungsanlagen’ and was recognized at the Energy Globe STYRIA AWARD 2024.
Use & Integration of Heat pumps
Cascaded heat pumps installed by Milteco have replaced oil- and gas-fired heat generation at ALWERA’s Wollsdorf site, supplying renewable process and space heating through a central hot-water system. The heat is used primarily for drying seed maize and pumpkin seeds, while the cooling generated simultaneously is utilized in tank rooms and cold-storage facilities.
The system is integrated into an internal heating and cooling network serving the drying plants, production halls, offices and storage areas across the site. With a reported heating capacity of 4.8 MW, a cooling capacity of 2.6 MW and an electrical connection capacity of 2.2 MW, the installation provides both heat and cooling from a single integrated energy system.
The heat pumps operate on 100% renewable electricity. As part of ALWERA’s wider energy-transition programme, photovoltaic capacity at the Wollsdorf site has also been expanded, further increasing the share of locally generated renewable energy.
Figure: Energy concept implemented at the Wollsdorf site (Sources: ALWERA/Estyria, Steirerkraft, Energy Globe STYRIA, Ascon3)
Benefit
The new concept is reported to save ~4.4 GWh of natural gas and more than 30 MWh of fuel oil per year, corresponding to ~1,100 t CO2 per year.
Key figures
| Dryer type | Stationary flat-bed dryers for pumpkin seeds; separate batch-type seed-maize drying installation |
| Drying products | Seed maize, pumpkin seeds |
| Operation | Seasonal, predominantly batch operation |
| Drying medium | Air |
| Product conveying | Batch filling onto perforated drying floor |
| Heating medium temperature | Hot-water system (60-75 °C) |
| Heat sources | Cascaded heat-pump system replacing oil/gas heat generation |
| Heat pump capacity | 4.8 MW heating; 2.6 MW cooling; 2.2 MW electrical connection |
| Flow temperature heat pump | 75-90 °C |
| Refrigerant | R1234ze(E) |
| Drying time | Several hours (pumpkin seeds) to 1-3 days (maize) |
| Start of operation | 2024 (commissioning: Aug. 2024; operating in 2025) |
| Capacity | n.a. |
| Dimensions | n.a. |
| Outlet condition drying medium | n.a. |
| Direct heat recovery | n.a. |
| Heat source for heat pump | Not publicly specified; cold side serves tank rooms and cold stores |
| Challenges | Retrofit at existing site; seasonal drying loads; integration of heat and cooling demand |
| Tracked parameters | n.a. |
More information
This information was provided by AEE INTEC.