System Performance of Stretched Membrane Heliostats

The optical performance of both focused and unfocused stretched membrane heliostats was examined in the context of the overall cost and performance of central receiver systems. The sensitivity of optical performance to variations in design parameters such as the system size (capacity), delivery temperature, heliostat size, and heliostat surface quality was also examined. The results support theconclusion that focused strethed membrane systems provide an economically attractive alternative to current glass/metal heliostats over essentially the entire range of design parameters studied. In addition, unfocused stretched membrane heliostats may be attractive for a somewhat more limited range of applications, which would include the larger plant sizes (e.g., 450 MWth) and lower deliverytemperatures (e.g., 450 degrees C), or situations in which the heliostat size could economically be reduced.