Design Solution · HVAC & Energy
Design Solution · Dream about it
Deep lake-water network as renewable heat sink/source.
The campus connects to a city lake-water network (GeniLac) that uses deep cold water from the lake as a renewable heat sink/source for cooling and heat-pump heating. Tapping a shared water body removes most mechanical chiller energy and the associated heat rejection.
Geneva's GeniLac network draws cold water from the deep basin of Lake Geneva — typically around 6°C at depth — and distributes it to connected buildings as a free cooling resource, displacing chiller plant that would otherwise run on electricity across much of the cooling season. The system is operational at city scale and the basic premise of surface-water cooling is well established in several European cities, so the principle is not speculative even if this record carries no project-specific evidence. For a campus connecting to an existing shared network the primary risks are on the dependency side: connection point capacity, contract terms, supply temperature guarantees across summer peak conditions and climate-affected lake stratification, and what the fallback strategy is if the network is unavailable or maintenance-shut during a heat event. The long-run climate question is real — deep lake temperatures can rise over decades, and a cooling system designed for today's baseline may underperform in a 2040s summer without supplementary mechanical backup. Before this becomes a project commitment, the network operator's contractual guarantees on temperature and availability, plus the backup position, need to be as robust as the energy savings case.
#lake water cooling #district energy #GeniLac