The patented new system harnesses a unique mixture of technologies to pre-heat domestic hot water for radiators, baths and showers while also generating electricity. More than half of domestic energy use in the UK is to heat water. At its heart is the use of heat pipes – superconductors of heat energy – found in high tech devices from PCs to the International Space Station where they prevent it from melting in the heat of the sun on one side and freezing in the vacuum of space on the other.
“Until now there was no system which fully addressed all the technical and practical issues that face making an entire building’s roof a solar-powered generator of both heat energy and electrical energy.” Heat pipes seemed to Dr Jouhara an obvious solution to a major tech issue with solar cell or photovoltaic (PV) panels used to generate electricity.
“PV panels have an inherent challenge to the engineer,” he said. “The more intense the sunlight the more electricity the cells will produce but only a fraction of the sun’s energy can be turned into electricity. “As PV cells heat up their electrical generation ability is degraded. Heat pipes, in this case, constructed in flat panels 4m x 400mm, will whisk that away to heat domestic hot water.”
PV cells cooled by Dr Jouhara’s methods outperformed identical panels by 15%. And rather than being wasted, almost the full spectrum of energy from the sun is harnessed. The new system also addresses a wide range of practical issues in installing solar panels in new properties.
“What was needed was an engineered, systems approach,” said Dr Jouhara. “Our solar panels are PV coated for the most southerly-facing aspect of the roof and are designed to clip together as a weather-tight roof as simply as clicking together laminate flooring.
“Currently the panels would get hottest in the summer …. Simply insulating the house below is not a good solution as that simply traps it driving up the PV panel temperature and further lowering its performance. With our system there is no waste heat.” A prototype is powering a standard UK 3-bedroom detached house. “Our flat heat pipes are so efficient that they can actually capture the energy from early morning dew evaporating off the trial roof,” added Dr Jouhara. http://www.alphagalileo.org/ViewItem.aspx?ItemId=156722&CultureCode=en
Dr Hussam Jouhara with his prototype hybrid solar panel. Credit: Image courtesy of Brunel University
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