Data centres run high-speed computer chips that get very hot. To keep them cool, some chips get liquid 'showers' or even relax in baths of cooling fluid, says Jonathan Ballon, CEO of Iceotope. This liquid cooling allows chips to run faster without burning out. One US hotel plans to reuse the heat from its servers to warm rooms and pools. Cooling is vital; a failure caused a big trading system outage in the US recently. Demand for data centres is rising due to AI but these centres can consume huge amounts of energy and water. Over 200 US environmental groups now seek a pause on building new ones. Iceotope’s liquid cooling uses less power and water and runs silently, cutting energy for cooling by up to 80%. Their system uses water-cooled oil-based fluid, keeping water in a closed loop to avoid waste. While some cooling fluids come from fossil fuels, none contain harmful PFAS chemicals. Some other systems use refrigerants with PFAS, creating environmental and safety concerns. Cooling methods vary: Microsoft once tried underwater data centres cooled by seawater but stopped due to costs, though it gained useful data. Future ideas include tiny liquid channels inside chips or special membranes that cool passively like tree leaves. AI drives demand for cooling since big models need a lot of energy and cooling, says expert Sasha Luccioni. She urges more transparency on AI energy use. Ballon says AI’s current big models have already pushed productivity to their limits. Liquid cooling innovations may help data centres stay cool, cut costs, and reduce environmental harm as they grow.