Public swimming pools facing closure because of soaring energy bills have been offered a lifeline via new technology to heat the water.

Mark Bjornsgaard, the chief executive of the tech startup Deep Green, has trialled the idea in Exmouth, Devon. He has put a small computer data processing centre underneath the pool and the energy from it heats the water.

The idea has taken off and up to 20 public pools could be upgraded to the heat system this year.

“We built a small data centre in Exmouth leisure centre. Most normal data centres waste the heat that the computers generate. We capture ours and we give it for free to the swimming pool to heat the pool,” Bjornsgaard told BBC Radio 4’s Today programme.

The technique works for the data centre and the pool – the heat from the computers warms the water and the transfer of heat into the pool cools the computers.

“It’s great for them – they get to reduce the cost of heating the pool and reduce the amount of carbon they use, and good for us because we can offer cheaper computer services because we don’t have the cooling costs,” Bjornsgaard said.

The idea was part of a change in the data centre industry, he said. For 30 years there have been huge buildings, often in the middle of nowhere, with millions of computers in them generating a vast amount of heat.

“As the world moves, we need 10 times the amount of computers and we cannot build 10 times the amount of data centres,” he said. “So there is a need to decentralise them and take little bits of them to where the heat is required.”

Sean Day, the manager of Exmouth leisure centre, said its energy bill was expected to rise by £100,000 this year.

“The partnership has really helped us reduce the costs of what has been astronomical over the last 12 months – our energy prices and gas prices have gone through the roof,” he told the BBC. “Looking at different ways of how we can save money as an organisation has been awesome.”

Jane Nickerson, the outgoing chief executive of Swim England, said she had been inundated by other swimming pools asking to be included in the project.

“Mark had a target of seven pools this year and he has upgraded that to 20. This could be a gamechanger, an absolute gamechanger for us,” she said.

The attempt to ease to energy bills comes as public swimming pools across the country are closing. Guardian research revealed England had lost almost 400 swimming pools since 2010, with parts of the country with the greatest health needs losing out the most.

Swim England said there was an urgent need to invest in the country’s pools.