Site Selection for Concentrated Solar Power System

Technology #14620

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Example illustrating sampled locations for evaluating site efficiency. Icon shading indicates efficiency of individual sampled locations. Blocked locations are shown as small squares.
Categories
Inventors
Alexander Mitsos
Department of Mechanical Engineering, MIT
External Link (mitsoslab.scripts.mit.edu)
Corey Noone
Department of Mechanical Engineering, MIT
Managed By
Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Publications
Site selection for hillside central receiver solar thermal plants
Solar Energy, Vol. 85, No. 5, (2011) 839–848

Applications

In a Concentrated Solar Power (CSP) system, a field of mirrors (known as heliostats) are used to reflect sunlight toward a central receiver, where the light energy is captured as thermal energy. The effectiveness of the overall CSP system depends on how efficiently the individual heliostats are placed, known collectively as the heliostat field. 

This tool can be used to evaluate the efficiency of such a heliostat field. It is designed to be used to site the type of CSP system recommended in this technology for a High Efficiency CSP system (MIT Case 16037), however it is also applicable to general CSP systems.

Problem Addressed

Calculating the efficiency of an entire heliostat field requires many factors to be taken into account — such as the sun's placement in the sky, or obstruction of the sun by local topography and neighbouring heliostats. These many factors make the overall calculation, and thus the selection of an ideal field, very computationally intensive.

Technology

This technology calculates the field efficiency of potential heliostat field positions, in order to converge on an ideal eventual placement. The following process is repeated iteratively for multiple candidate positions, at an increasing level of accuracy as higher potential regions are found. 

For each potential position, the tool simplifies the overall calculation by averaging over the efficiency of sample points within the field. At each sample point, factors considered in the efficiency calculation are the cosine efficiency (determined by the relative angle of the heliostat to the sun and to the receiver), potential blocking of the sun from surrounding hills, and an approximation of the blocking from neighbouring heliostats. These efficiencies are calculated across the whole year, in order to determine efficiency over the different positions of the sun.

Advantages

  • Reduces the computational intensity of calculating heliostat field efficiency; thus
  • Locates suitable sites for a concentrated solar power system