Solar City of Satigny

Initially, for its 4 buildings and 10 building entrances of 78 flats with 9,550 m² of living space "Aux Cépages de Satigny", the promoter had planned a large classical centralized oil heating system with a large tank in the middle of the district.

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Based on a large surface area of thermal solar collectors connected to a new generation heat pump (PAC), this SUNERGIE® system allows for optimal exploitation of solar energy, when sunshine permits, or via the PAC if the sun is lacking. This makes it possible to make the most out of the diffuse energy (coming from all directions) that the solar collectors collect.

Decentralised DHW production in the flats. In fact, each flat has its own 300-litre water heater, representing a large and sufficient stock of water of 23,000 litres, which is almost invisible. This is also unique in Switzerland. This decentralised production considerably reduces the problems of scaling in the pipes by eliminating the circulation of DHW. It is the only DHW production system to be "Outside the Legionella risk group according to EU/CH".

The excellent building envelope ensures a pleasant temperature in the flats in all seasons, while the double-flow ventilation with its Canadian well makes it possible to combine energy savings with healthy, filtered air for the inhabitants.

In keeping with our proven concept of "multi-functionality", the stale air from the flats is not only discharged to the outside, but is first sent to the car park to ventilate it, much better and much cheaper than any separate ventilation system (required by Swiss car park ventilation laws). It then exits through the air outlets, which also serves as smoke extraction for the fire brigade in case of a burning car.

The SUNERGIE® system control, the brain of the installation, with Internet access. It allows a simple, fast and efficient management of the 10 installations by the responsible engineers. The controls are carried out remotely and live. The system also provides for individual temperature control for each flat.

Our idea was to be able to use both direct and indirect solar energy with the same energy collection system. We needed solar collectors that could work all year round, even at night. Without polluting the environment and without being dependent on foreign energy.

This is what we submitted to the client as an idea, to realise 10 decentralised, independent and standardised installations per building. And thus abandon the complex centralized concept which is almost always less advantageous than small decentralized systems.

ERTE was able to convince the owners to go for this SUNERGIE® solution.

This SUNERGIE® system intelligently uses a new standardised hydraulic distribution system, the enerBus®. Indeed, this system does not use vertical geothermal probes which are fatally expensive and cannot exploit solar energy.

During the heating period from November to January, nearly 63% of the solar energy in Geneva is diffused, a maximum of energy is captured thanks to this system, whatever the weather conditions:

  • Sun
  • Wind
  • Rain
  • Snow
  • Frost at night

This SUNERGIE® system even uses the energy of the… moon. It’s a joke, but not that much because this “solar-energy” system is able to work and collect energy during the night.

The use of solar collectors is multiplied compared to traditional installations and no supplementation with fossil energy is necessary. No other system except SUNERGIE® is able to operate the solar collectors 365 days a year, 24 hours a day.


Thanks to its philosophy of simplification, SUNERGIE® is the most comprehensive, least expensive and most efficient solution for designing systems with high solar autonomy.

It is a “one size fits all” CVS-Solar system, for :

  • new buildings
  • existing buildings
  • housing
  • craft industry
  • administration
  • hotels
  • restaurants
  • hospitals
  • clinics
  • EMS

A universal system, so to speak.

This achievement has earned ERTE the Swiss Solar Prize 2011 in the category of planners.