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Using CO₂ to heat and cool urban areas

ExerGo has developed an efficient heating and cooling network solution. Using CO₂ as the heat transfer fluid (to both heat and cool), the company boasts an 85% reduction in energy consumption compared to fossil-fuel-based solutions – with zero CO₂ emissions.

“Projections show that by 2050, around two-thirds of the population of Europe will live in urban environments,” explains Alberto Mian, CEO of this Energypolis spin-off. “This opens the door to numerous synergies in dealing with the increased concentration in energy demand and ever more ambitious climate goals.” The CO₂ network concept developed by ExerGo thus targets towns and ci-ties, where it enables exchanges of waste heat between buildings and provides an efficient urban heating and cooling network. In this way, the residual heat from data centres, supermarkets and office buildings can be reco-vered and used to supply domestic hot water and hea-ting to apartments for example.


Existing district heating and cooling networks use water in a closed circuit as the heat transfer fluid. ExerGo has replaced the water with R-744 CO₂. This fluid, which is commonplace in commercial and industrial refrigeration, has an exceptional energy density. “We use R-744 not just as a coolant but also to transport low-tempera-ture heat from the environment – such as lakes, rivers and underground – and recover it through decentralised heat pumps.” This is a typical application for CO₂ in industry (CCU), using a system that injects and stores it in the network rather than discharging it into the atmosphere.

ExerGo is targeting two customer profiles: utilities (through the installation of large-scale systems) and real estate developers planning on building ecodistricts. The company is initially focusing its strategy on deploying heating and cooling services, but in the longer term plans to extend the network to include the production and distribution of electricity with gas micro-CHP units using fuel cells  for CO₂ capture. To publicise its technology far and wide, ExerGo is showcasing it in Switzerland and around Europe through collaborations with partners including – in Switzerland – the Geneva utilities company (SIG) and the energy company OIKEN. The system is currently installed in Sion, where it connects three buildings on the Energypolis Campus. ExerGo is being supported by the Swiss Federal Office of Energy and The Ark Foundation.

This article was originally published in CleanTechAlps’s Special Report (November 2022)

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