Construction works about commence on STE test site

Construction work is about to commence for the installation of a Solar Thermal Energy test site on a veal farm near Saint-Georges-du-Rosay in Northern France. 

On February 15th 2021, a construction team meeting was held to schedule the construction timetable. 


The farmer, Mr Vaucelle raises his veal calves in a modern building constructed in 2018 with the latest animal welfare standards. There is a maximum of 396 calves in the building. Mr Vaucelle feeds his calves with reconstituted milk and fibrous foods such as straw stoppers. Milk is delivered by an automatic system. The calves are reared on the farm for 5.5 months and while the buildings are empty there is a deep clean to prevent transmission of disease to the next batch of calves.

Mr Vaucelle requires a large consumption of hot water all year round to prepare the milk for his veal calves. Calf production requires 1550 litres of hot water per calf. This involves heating water up to 75 or 85°C to thoroughly dilute the milk powder with the water. And right after, the milk is again mixed with cold water to be delivered at 45°C to the trough. Mr Vaucelle also needs hot water to clean the stalls between each batch.

Mr Vaucelle uses a gas boiler to heat water. The rearing of calves consumes from 9,5 to 12 kg of gas per animal. At today's price, the invoice of propane gas is about 665€ (without taxes) per metric ton.

 This energy has two problems :

  • It is a fossil-fuel and its combustion generates CO2 that contributes to climate change.
  • It has a very variable cost that can destabilize the farm economy.

The installation

For these reasons, the aim of the project is to achieve and replace 70% of fossil-fuel use (propane gas) with solar thermal energy. To do this, it’s necessary to adapt the power of the installation to the daily needs of the farm.

In addition, during summer with so many sunny days and during periods without animals, the installation will have to store in the earth the unused energy and reuse it after.

We plan to install 16 STE panels on the French Pilot Site. Each panel has a power of 2.5 KW and 300 litres of solar hot water storage. Therefore, the total power of the installation will be 40 kW with 4800 litres of solar hot water storage. The daily hot water need in the pilot site is about 3200 Liter/Day at 80°C.

While the buildings are empty, the panels are still producing hot water, some of which is used by the farmer for cleaning the buildings. 

It is therefore necessary to store the energy in the earth for these periods to protect the system against overheating. To do that, the hot water not used in the building is driven through another network in the ground to dissipate heat. In addition, this energy dissipation system saves water because it will not leave in steam. After that, it is possible to reuse the energy stored in the ground to heat the water during cloudy days. Finally, this system of dissipation and energy storage can save more or less 10% of the energy needs of livestock.

From left to right :

  • Mr Zanni – ZANNI TERRASSEMENT (Earth-moving company)
  • Mr Jeuland – FENGTECH (Icare4Farms partner - STE supply company)
  • Mr Alainmate – SARL LEFORT (Installer)
  • Mr Zanni – ZANNI TERRASSEMENT (Earth-moving company)
  • Mr Vaucelle – EARL DU BOULAY (Icare4Farms sub partner - Farmer and owner of the French Pilot Site)
  • Mr BEAUJEAN - AGRICULTURES TERRITOIRES Chambre d'agriculture Pays de la Loire (Icare4Farms partner)

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