This Small Business Innovation Research (SBIR) Phase I project will lower the cost of parabolic trough concentrating solar power (CSP), which uses trough-shaped mirrors to focus sunlight on tubes to harvest heat for generating electricity. The tubes are coated with a dark substance, 'absorber', that efficiently absorbs light and can withstand high temperatures. In present-day commercial designs, the absorber tube is packaged inside a vacuum-holding glass sheathe to form a 'receiver'. Standard receivers have drawbacks: (1) When gas leaks into them, they fail. (2) The absorber pipe radiates heat in all directions through the transparent sheathe, wasting energy. (3) The absorber coatings are complex. Receiver designs that avoid these problems require novel absorber coatings and cost-effective ways to apply those coatings during manufacture. This project will improve a recently developed novel absorber coating and demonstrate a simple, cost-effective method for applying it to receiver tubes. Improvements include experimentally investigating why the coating in its present form resists chemical degradation under realistic operating conditions and adjusting its composition accordingly to further increase its performance. The coating manufacturing and application processes will be demonstrated at laboratory scale by building and performance-testing actual receivers.
The broader impact/commercial potential of this project will be achieved by reducing the cost of parabolic trough CSP. Parabolic-trough CSP is being developed rapidly in the US and other countries that seek to reduce pollution and increase energy security, creating a growing global market for CSP components. Receivers are an indispensable and costly part of parabolic trough CSP. For example, a parabolic trough CSP plant large enough to produce 250 megawatts of electric power contains about 60,000 receiver tubes. This SBIR project, by producing a lower-cost, vacuum-free receiver that uses a novel absorptive coating, will reduce both the capital and maintenance costs of CSP. The new design and materials will simplify receiver manufacture, improve performance, and do away with failure-prone vacuums. Scientific understanding of the properties of absorber coatings will be increased by experiments performed under this project, and new receiver-manufacturing technology will be demonstrated. Reducing the cost of energy from CSP will speed deployment of this inexhaustible, 100% domestic source of power, speeding progress toward a pollution-free, secure energy economy.
