Salaspils Siltums solar district heating plant!1

The largest Solar thermal district heating plant in all of Eastern Europe was made by Filter in cooperation with Arcon-Sunmark A/S. The award winning feat of engineering results in a 1720 panel solar field providing an annual output of 12000 MWH, which is combined together with a 3 MW Biomass based boiler. 


The main purpose was to reconstruct and convert a conventional district heating plant into a newer modern renewable energy based district heating plant. The common problem of Solar thermal energy level fluctuations through-out the season has been solved with an 8000m3 accumulator tank which stores energy using glycol heat exchange.

The previous old systems have been integrated with the new installed technology and will serve as a backup heat source during maintenance works, to ensure a steady and constant heat supply. The new installed systems include a 3 MW Biomass based boiler that provides extra heating during winter time. All the additional heat sources were integrated and synchronized with the existing heating network.

The ambitious and successful project has gotten nation wide recognition for its' engineering feat, Salaspils Siltums district plant has won the prestigious Latvian construction award “Grand Prix” from amongst 162 nominees. Achieving the “Largest and most significant project of the year” award, the winner is publicised all around national media (Dienas Biznes,,,

Solar panels (Glycol filled) - 1720 Panels
Annual Solar thermal output – 12000 MWH
Accumulator tank capacity – 8000 m3
Biomass based boiler – 3 MW
Cylindrical accumulator tank - (Diameter: 20m, Height: 28m)
Panel effective area coverage - 21595 m2 (2.1 hectares)

Date: 2018 – 2019

Scope of supply
• Design works
• Steam boiler
• Storage tank
• Electrification and automation of process
• Installation
• Commissioning
• Service

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