After years of ‘growing pains’, Oxfordshire inventor Tom Smith has finally found the funding to develop his low-cost solar pump to irrigate fields in the developing world.

Now all he needs is a local landowner with a borehole or well where he can test it out.

Mr Smith, a Cambridge engineering PhD, has developed the pump system with no moving parts, using shock waves from oscillations in solar-heated water.

He said: “The problem with solar pumps in the developing world is they are comparatively expensive and fragile. They are not maintainable or repairable in extreme conditions.”

His company, Thermofluidics, of Begbroke Science Park, is finally poised to expand after several years in the doldrums since it was set up in 2006.

He said: “It is a very difficult piece of technology. It is simple, in that if you have the technology and the materials right, you do not need precision manufacturing. But the physics behind it is very sophisticated. It has been a long process.”

He first had the idea while studying physics at Imperial College before moving to Cambridge, where it was the subject of his doctorate.

“Like many inventors I have met, I had the idea first and wanted to apply it to something useful.”

At first he was funded by grants, including a graduate award from the Royal Institute in 2004, but then the recession hit.

“I had periods when I was working on it with no funding at all. At the moment we are developing much faster because the money has started to come in.”

Things started looking up after the company's chief executive Mark Bryant, a former managing director at Accenture, read about the project after it won a £100,000 award from The Sunday Times and invested some of his own money.

More funding came from the Carbon Trust, which is putting up £300,000 of the £500,000 cost of running the trials, and the California Energy Commission.

Mr Smith, 35, said: “It reaches a critical mass and people find it much easier to fund something which is already funded. Once you have something which is up and running, people start piling in.”

Thermofluidics’ latest award is from the Wellcome Trust, whose spokesman, Richard Seabrook, said: “Supporting initiatives that address the global threat of food security and access to nutrition is one of our core strategic research challenges.

“Beyond the obvious benefits of being able to grow food crops, access to clean water and sanitation has an enormous impact on public health."

Thermofluidics hopes to form a partnership with an organisation which provides expertise to help developing countries to manufacture foot treadle pumps.

Such pumps often need several hours of hard manual labour each day, diverting farmers’ time away from other tasks such as growing food. An unexpected illness can lead to the loss of an entire harvest.

Mr Smith hopes to demonstrate that his £50 pump has superior performance to a treadle pump, and the project will include installation skills, pump construction materials and manufacturing techniques.

Mr Smith has added to his original technology with a hydraulic ram that can draw water up from 100 metres below ground — and pressurise it at the surface. He explained: “We use the time difference between the solar water heaters to drive boiling and condensing, generating oscillations which are harnessed into shockwaves to draw the water up to the surface.”

Mr Smith said: “Our intention is that Thermofluidics’ pump will ultimately improve crop yields, income and health outcomes for up to 550 million malnourished smallholders across the developing world.”

Engineer Tom Law (pictured) is working on one prototype pump in the stairwell of Oxford University's engineering department. Another is in a field in Devon, while a third is being tested in the South of France.

Mr Smith said: “We are wanting to move it out of the stairwell and we are looking for someone with a borehole or well.

“The Environment Agency will allow us to do it, and we have a site, but it is extremely exposed and right next to the road.

"We are preparing to move it out to a developing country where we would like to leave it for longer periods.

“But before that we need to go through a series of tests. We have to know that it is working very well because it has to survive extreme environments, so we have to put it through intensive tests.”

As well as irrigation, the technology could be applied to water pumping for drinking and sanitation, solar hot-water, refrigeration, and oxygen enrichment of air.

Mr Bryant is talking to possible trade partners who might be interested in using the pump as an energy-efficient way of circulating hot water in building heating systems.