April 12, 2014 – There are two types of solar renewable technologies. The first, solar photovoltaics, is at best marginally efficient when converting energy from sunlight into electricity. And when the sun is not shining…well you get it. The second, solar thermal involves putting mirrors on motors to track sunlight. The mirrors concentrate the light to generate heat which then boils water to drive turbines. This technology can store the excess heat in molten salt. But it is expensive when compared to the first technology.
But what if we were to combine the two creating a hybrid system? Then the conversion inefficiencies of the former would be offset by the continuous energy that could be gained from the latter. Overall the amount of energy from sunlight could top 50% conversion efficiency. A combination of solar photovoltaic panels with solar thermal would give us the best of both worlds. Photovoltaic technology efficiently converts only certain light wavelengths. Infrared and ultraviolet light, both strong heat emitters, are not processed by these types of panels. But if solar panels also captured the heat properties of these wavelengths using heat traps situated behind the panels then you would have a hybrid technology. In the past water pipes have been combined with solar panels. But at best the water pipes retained just enough heat to use for residential hot water usage. What researchers have in mind for the next generation hybrid solar is using a heat trap that is far more efficient. In one proposed technology nanoparticles suspended in fluid absorb the heat from infrared and ultraviolet light. This raises the temperature dramatically making it possible to use the heated fluid to produce energy.
Research is ongoing with a number of projects being funded by ARPA-E. The goal is to test these new technologies in the next 3 to 5 years and then make them commercially available.