in a laboratory on the outskirts of hull, a high—tech system that has taken 15 years to develop. essentially, it is a way of cooling computers down without the expense and carbon emissions associated with conventional air conditioning. it's driven by water evaporation, not by a refrigerant. it's the stability of the nature. if it evaporates the water, you have loads of energy being taken away by changing the waterfrom liquid to the moisture in the air. data centres are a few of us will ever visit, but they are the backbone of our internet use. processing everything from simple e—mail to online shopping. and all of this generates heat. hull city council has its own data centre, and by using this new technology the authority's been able to save thousands of its cooling bills and reduce emissions. everything we have nowadays, we just store electronically. so it is a growing carbon impact for the council, but also globally as well. it is a big global challenge.