Hybrid solar panel heats water while generating electricity
UK renewables company Naked Energy has invented Virtu, a hybrid solar panel that simultaneously heats water and generates electricity.
The technology, developed by Naked Energy’s chief engineer Richard Boyle, integrates an electricity-generating photovoltaic cell into a hot-water-generating solar thermal panel. The solar thermal panels are placed into vacuum tubes and are unaffected by ambient temperature.
Nick Simmons, chief financial officer of Naked Energy, told The Engineer: ‘We can create more useful energy per square metre than conventional panels on the market today.’
Through combining the two technologies, Boyle was able to address one of the fundamental problems facing photovoltaic cells.
‘When photovoltaic panels get hot they become less efficient. For every 1º rise in temperature [from 25°C], you lose half a percentage point of efficiency,’ said Simmons. ‘A very efficient photovoltaic panel has a maximum efficiency of approximately 18 per cent. But by the time you get up to 65°C, which is quite a normal temperature on the face of a solar panel, you’re down to something like four per cent efficiency.’
Heat is transferred away from the photovoltaic cells with a patented thermosyphon technology that harvests the unwanted heat from the photovoltaic cell to heat up water.
As a result of taking the heat away and cooling down the photovoltaic cell, it is possible to generate more electricity than conventional photovoltaic cells.
‘We bond the photovoltaic cells to the thermosyphon, so there is a very small temperature differential between the photovoltaic cell and the thermosyphon. This means the photovoltaic cells are maintained at a uniform temperature,’ said Simmons.
Naked Energy has been working closely with Prof Peter Childs, an expert in heat transfer from Imperial College London, to further improve the efficiency of the solar panels.
Childs recently found that Naked Energy’s photovoltaic cells generate 40–45 per cent more energy as a result of the heat transfer method.
‘Sussex University is helping us put the product into production,’ said Simmons. ‘It’s been helping us make dyes and various tools to press the substrate of the thermosyphon, so we now have a way to manufacture the technology at scale.’
Naked Energy is currently on a trade mission to San Francisco that is being run in association with the Technology Strategy Board, UK Trade & Investment and other private sponsors.
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Readers' comments (25)
Brilliant device. Congratulations to all concerned. Now just build a great big factory to produce them here in the UK and export them round the world. Perfect.
This is an excellent idea if it can be done cost effectively.
For some time I have been suggesting to people who already have Solar Panels that they should rig up a pump to take water from their water butt and feed a sparge pipe which dribbles water over their arrays to keep them cool. It then returns under gravity to their water butt. However no-one takes me seriously.
For ease of installation the pump could be powered from its own small solar panel so that it only runs when there is a high level of sunlight.
There may be a few minor wrinkles to iron out such as melting water butts but hey nothing's perfect.
All it needs now is the addition of the new see through photovoltaic film for a triple effect. Anyone got any further ideas?
About time too! Having one system on the roof to do one thing when there is a need for two systems, electric and generation and hot water was always half a job and a waste of space. The report is very illuminating where it states only 4% effectiveness when the photovoltaic panels get hot. Companies who supply these systems seem to have forgotten to mention this!!
I hope this product can be produced in, and marketed from the UK; it would be a sad day if we cannot do this and have to sell yet another good idea to a foreign company in order to get it made. Come on local enterprise groups get in contact with Naked Energy.
We have an sub division in Australia and for years I've thought why doesn't someone combine the two. Excellent idea and hopefully durable product we'll sell them in Australia for them.
Great product but a fully certified hybrid panel (including MCS) can be purchased today! See www.volther.co.uk and the manufacturer http://volthersolar.com/
Unfortunately, this system is not so useful in ME or Africa because the excessive heat there does not let any utilization for such accumulated heated water.
Yes !! I have an idea to utilize the product of heated water:
It is the Thermal Desalination, which is most needed in MENA region.
One of the observations about currently available PV installations is the thermal build-up so it was about time that a system to use the heat as well as the electricity generated. Interesting that we now have an indication of the inefficiency levels as the panels heat up.