Using Concentrated Solar Thermal Technology to Capture and Store Heat

Using Concentrated Solar Thermal Technology to Capture and Store Heat in a New Way

In recent years, solar thermal technology for electricity production has fallen behind that of solar photo-voltaic or PV installations due to the rapidly falling prices for solar panels and lack of relevant research spending. One of the advantages of solar thermal electricity technology is the ability to store energy as heat before converting it to electricity.

Here is some new research news being conducted by Sandia National Laboratory using concentrated solar thermal technology to store heat energy in a new way.

Inside Sandia Labs falling particicle test unit for solar thermal electricity

Inside Sandia Labs falling particicle test unit for solar thermal electricity

Researchers at Sandia National Laboratories are working to lower the cost of solar energy systems and improve efficiencies in a big way, thanks to a system of small particles.

This month, engineers lifted Sandia’s continuously recirculating falling particle receiver to the top of the tower at the National Solar Thermal Test Facility, marking the start of first-of-its-kind testing that will continue through 2015. The Sandia-developed falling particle receiver works by dropping sand-like ceramic particles through a beam of concentrated sunlight, capturing and storing the heated particles in an insulated tank. The technology can capture and store heat at high temperatures without breaking down, unlike conventional molten salt systems.

Conventional central receiver technologies are limited to temperatures close to 600 degrees Celsius (1112 degrees Fahrenheit), while operating temperatures for the falling particle receiver could exceed 1,000 degrees Celsius. Higher temperatures mean more available energy and cheaper storage costs because less material is needed to transfer heat.

Sandia engineer Cliff Ho, the project’s principal investigator, said the goal of the testing is to develop a prototype, cost-competitive falling particle receiver that demonstrates the potential for thermal efficiency greater than 90 percent, while achieving particle temperatures of at least 700 degrees Celsius.

“This technology will enable higher temperatures and higher efficiency power cycles that will bring down the cost of electricity produced from concentrating solar power,” Ho said.

In addition, the ability to cheaply and efficiently store thermal energy directly in the heated particles will enable power production at night and on cloudy days.

Falling particle receiver technology is expected to further advance the state-of-the art in concentrating solar power tower systems capable of generating up to 100 megawatts of electricity.

Sandia’s partners in the Department of Energy project are the Georgia Institute of Technology, Bucknell University, King Saud University in Saudi Arabia and the German Aerospace Center. The project is funded by the U.S. Department of Energy’s SunShot Initiative, which aims to reduce solar energy costs and expand the use of solar energy technologies throughout the United States.

Sandia design engineer Josh Christian said the on-sun testing at the solar tower will occur in two phases. First, researchers will test an insert designed by Georgia Tech that slows falling particles inside the receiver like a Pachinko board to increase the temperatures of the particles as they fall through.

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This post was prepared by Solar Thermal Magazine staff.

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