Tech for Green: Renewal of the heating and cooling system at the EPFL Lausanne

EPFL Lausanne
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EPFL and the University of Lausanne’s heating and cooling infrastructure was outdated, inefficient and carbon intensive. The university campus was heated through a thermal power station and the Pierettes pumping station, consisting of two heat pumps powered by two turbines fuelled by oil.

Innovative Solution

To help the university switch to 100% renewable energy to power the heating and cooling system, Bouygues Energies & Services re-designed and upgraded the university’s thermal infrastructure to reuse as much energy and water as possible. The Pierettes pumping station’s capacity was doubled via the installation of a strengthened network of pipes, whilst the thermal power station was extended with four new heat pumps and the removal of the two oil-fired turbines. Additionally, the thermal power station was also raised to house a data centre, covered in solar photovoltaic panels.

How It Works

Water from Lake Geneva is pumped through the Pierettes pumping station. A proportion of the water goes immediately into the campus’ cooling network, whilst the rest goes into the thermal power station. Here, the heat pumps extract energy from the water and convert it into heat that can be used to warm the campus buildings. This process cools the water, which can then be reinjected into the campus’ cooling network. Simultaneously, warm water is produced from the cooling network, which can be reinjected into the heat pumps to be used in the heating network.

Additionally, the data centre will be cooled by the cold-water discharges from the thermal power station and will warm the water through heat released by the data servers.

Client Benefits

This recovery and reuse of thermal waste reduces the amount of lake water initially pumped. «The water in the lake feeds the heat pumps, but it has many other uses,» says Vicent Pelejero, project manager. “It makes it possible to cool the buildings, to serve the industrial water network or to cool the data centre.» As the heat pumps are no longer fuelled by oil turbines, the new thermal infrastructure has eliminated 1800 tons of CO2 per year.

Key Figures

1800 tons of CO2 eliminated per year due to this renewal project.

Maturity Level

Level 1 : Proof of Concept or lab test

Level 2: Tested under real life conditions

Level 3: Live solution

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