Scientific breakthroughs often follow a collective focus on an issue or problem. When a tipping point is reached, the combination of small solutions across sectors spurs a giant leap forward. Renewable energy development has been a growing focus of international research over the last 3-4 decades and advances in clean energy technology have coincided with the rise of supercomputers, microtechnology and biomimicry. Biomimicry, for example, allows scientists to solve technological problems by copying structures and material qualities found in nature.
Bruno Michel, of IBM Research, is merging strategies from these different applications to create a low-cost and efficient solar collector. The mirrored, parabolic dish that his team developed concentrates the sun’s energy 1,000 fold and doesn’t melt in the process. The system they built is called High-Concentration Photovoltaic Thermal (HCPVT).
Now, let’s break that down.
High-Concentration solar systems use mirrors to direct high amounts of energy to one spot. Imagine the power of a magnifying glass to direct sunlight and set a piece of paper on fire. Next, there are two types of High-Concentration solar systems: photovoltaic and solar thermal. Photovoltaic cells convert sunlight directly into energy while solar thermal uses collected heat to run steam turbines that produce energy.
Previously, High-Concentration Photovoltaic systems competed with Concentrated Solar Thermal systems. However, Michel’s new HCPVT system combines both types of concentrated solar to achieve higher rates of energy capture. The union of these two approaches creates a stronger system than either product on its own. In addition to using mirrors, the HCPVT system employs sun-tracking software to reposition collectors throughout the day to receive the most sunlight.
Now, let’s get back to the magnifying glass. Not surprisingly, one of the biggest roadblocks to both types of High-Concentration solar (photovoltaic and solar thermal) is that the heat produced can melt the structural components of collectors in seconds. In order to combat this problem, older systems have employed toxic coolants and costly techniques to dispel waste heat into the atmosphere.
The development of a new, non-toxic cooling system was born out of an interesting cross-sector pollination. Michel’s team used a biomimicry-based microtechnology used to cool microchips in supercomputers. The microcooling technology is based on the veins and arteries that carry blood through the human body. Coolant runs through small channels mounted only a few micrometers off the photovoltaic chip. This method draws heat away from the chip ten times more effectively than a passive cooling system and allows the capture of more solar energy.
Not only is the new system more effective, it also uses 50% of the waste heat for desalinization or air conditioning. The system can produce 30-40 liters of desalinated, potable water per square meter of receiver area per day. Depending on the number of collectors, this could provide a significant amount of drinkable water in hot, dry climates. It could also be essential for regions lacking water conveyance infrastructure. The system can also provide air conditioning to reduce the energy load of surrounding buildings. An adsorption chiller creates a thermal cycle with a silica gel absorber that converts heat energy into cooling power. Normally, temperature control in buildings is one of the most costly operations both environmentally and economically.
You might think that combining so many technologies would be cost-prohibitive, but “the design of the system is elegantly simple,” said Andrea Pedretti, of Airlight Energy, part of the HCPVT development team.
We replace expensive steel and glass with low cost concrete and simple pressurized metalized foils. The small high-tech components, in particular the microchannel coolers and the molds, can be manufactured in Switzerland with the remaining construction and assembly done in the region of the installation. This leads to a win-win situation where the system is cost competitive and jobs are created in both regions.
This production strategy is another example of cross-industry pollination. Developers utilized economic tools to decentralize the production line and create regional jobs. Decentralized production and local job creation is a key response to historically mismanaged globalization that eliminated regional manufacturing, small businesses and weakened rural economies.
The good news is that in addition to creating jobs, the HCPVT system can keep the cost of solar capture as low as $250 per square meter – three times cheaper than comparable systems. When all is said and done, the cost of energy per kilowatt-hour (kWh) should be less than 10 cents. Furthermore, the modular design of the HCPVT system allows it to be adapted for small and large-scale applications. The collector could be used for remote research facilities, workstations, military bases, resorts or regions lacking a power grid.
Let’s review these points: The HCPVT system provides clean energy, potable water, and air-conditioning from one source at a low cost. Michel addressed three resource needs simultaneously while making each component stronger in the process. This giant leap forward illustrates the advancements possible when scientists are allowed to share technological ideas freely across industries and nations. Keeping these intellectual channels open is the key to fostering continued breakthroughs in global resource management.
Article by Rayna Gordon-Hellman, appearing courtesy Celsias.