
Veolia, a global corporation with focus on transport, waste, water and energy built and operate a new district heating network for the city of Voreppe, France.
For this solar installation, the space available for collectors was limited to a structure in midair between two buildings. Having a high solar yield was important criteria. Consequently, Veolia chose the well-designed Savosolar solution and its Savo 15 DG flat plate collectors being the most efficient in the market.
This installation in Voreppe was Savosolar’s first turn-key delivery for district heating in France. It raised interest among the district heating sector showing the potential of solar thermal as a clean heat production.



Løgumkloster Fjernvarme is a district heating company which annually supplies 35,000 MWh of heat to over 1,500 customers. Heat is produced with a hybrid heating system consisting of a 3 MW pellet boiler, a 1.3 MW hybrid heatpump, a 3 MW absorption heat pump and a solar collector field of 15,300 m2. Additionally, the plant has two gas engines which are capable of producing 7.6 MW of heat and 6 MW of electricity and a 10 MW gas boiler which acts as back-up.
In 2015, Savosolar delivered a 9,700 m2 solar thermal field to Løgumkloster. The second order of 5,600 m2 was delivered and commissioned in the beginning of 2016. The complete field consists of 1030 Savo 15 SG collectors and covers about 20% of the annual thermal energy need of the district heating network. The largest part of the heat demand is covered by the pellet boiler, but Løgumkloster Fjernvarme has plans to change this in the future by extending the solar field and building a large seasonal water storage.

Lolland forsyning’s district heating plant in Søllested is located on the island of Lolland and was the first installation, where Savosolar’s double glazed collectors were used. The double glazing reduces heat losses through the glass side of collector and offers a higher efficiency, especially at higher operation temperature levels and during the darker months of the year. Søllested district heating plant has ca. 500 customers and also uses a 5 MW straw boiler and an oil burner to produce its heat.
The collector field in Søllested has a so-called hybrid field, with both single and double glazed collectors. The single glazed collectors are in the cold end of the collector rows and increase the low temperature as rapidly as possible, while the double glazed collectors are located in the warm side of the collector rows where it is more important to reduce the heat losses.
In Søllested, Savosolar was faced with a special challenge since the customer’s land has a sewerage pipe running through it. Since the owner of the sewer pipe needs to be able to access it in case of maintenance, Savosolar supplied a collector field which both optimised the use of the available land, while still providing access to the sewer pipe

Largest solar thermal plant in Finland
Savosolar has been selected as general contractor to build the largest solar thermal system in Finland to date, on behalf of Etelä Savon Energia Oy for its district heating network, which supplies households with healthy heating. The plant operate as an additional peak load sources during summer season while the main boilers are out of service.