A team of engineers has developed a hybrid solar energy converter that uses energy from the sun to generate electricity and steam with high efficiency at a low cost. This device allows the industry to make use of a broader spectrum of solar energy.
Photovoltaics is the most common way of harnessing energy from the sun. These solar cells convert light into electricity via semi-conducting material, and they’re built into everything from the grid to garden lights. However, there are other ways to collect solar radiation. Solar concentrators don’t collect light; instead, they collect heat by focusing the sun’s rays to heat a contained fluid. This system can be used to generate electricity, to heat homes, or for other industrial purposes.
These two systems are usually separate. Attempts have been made to combine both designs into a single hybrid device, but they turned out to be more expensive or to have lower efficiency, until now. Engineers claim to have mixed the best of both worlds with this new hybrid solar energy converter.
The converter looks like a mounted satellite dish, with a device suspended over the center of a parabolic collector. The dish is mirrored to direct the sun’s rays onto the box in the middle. This section contains multi-junction solar cells, which absorb and convert ultraviolet and visible light into electricity. Additionally, these cells redirect the infrared light to a separate thermal receiver higher up in the device. This receiver captures the heat and turns it into steam.
The new hybrid converter saw a total collection efficiency of 85.1%, while the steam can be heated to 248°C (478°F), which is a considerably higher temperature than other thermal energy collectors. The steam is hot enough for many industrial processes, including sterilizing, pasteurizing, drying, and curing.
The team, which consists of researchers from the University of San Diego, San Diego State University, Tulane University, Otherlab, and Boeing-Spectrolab, claims that once the device is scaled up, it could run for as low as 3 cents per kilowatt-hour. The research is detailed in the journal Cell Reports Physical Science.
