Concentrating Photovoltaics (CPV) have an inherent design flaw: Concentration increases power production in PV, however heat decreases power production in PV. Conventional CPV have used exotic materials and expensive solar cell alternatives. The creation of triple junction cells was designed to handle the excessive heat, but they come with an excessive price (about $400/Wp).
A study conducted by Sandia National Laboratories documents that at 75 degrees Celsius, typical silicon solar cells drop nearly 20% in Voc efficiency.
V3Solar has designed an intelligent solution. Instead of solar cells mounted on a flat surface accumulating and collecting heat, solar cells are mounted on a spinning, conical form factor. This innovation of spinning solar cells provides the long awaited solution of minimizing the heat with sunlight concentration in order to maximize the efficiency of the solar cells.
The objective of this initial test was to compare the power generating and cooling capabilities of the Spin Cell. A control was used as a basis of comparison.
The Spin Cell prototype was connected wirelessly to a series of sophisticated data loggers and information capturing devices. Info such as heat, RPM, amps, volts, etc., was captured. All test results were recorded under industry approved standards.
Initial tests verified performance of greater than 20 times sun performance. This test was conducted using a 20X lens and 1X sun mono silicon PV.
A control was used for all Spin Cell tests. The control was a static panel with the same surface area of PV as the Spin Cell.
Under the same test conditions the static panel (the control) recorded temperatures of greater than 260 degrees F at 20x sun concentration and the PV failed. The PV showed a 20X increase in production for less than 1 second before performance degraded because of the high temperature.
Under the same concentration and test conditions, the Spin Cell was dramatically cooler and performed flawlessly. With the Spin Cell, the temperature of the PV never exceeded 95 degrees F (15 degrees above ambient). It was determined that the Spin Cell would perform indefinitely at this level of light concentration.
The table in figure 1 shows the recorded results of tests conducted when solar cells are rotating upon an axis, periodically moving in and out of concentrated sunlight. There is a 39% to 74% (based on Celsius) reduction in heat as compared to solar cells that are stationary under the same concentration conditions.
Test results were measured with both infrared pyrometer and surface mounted thermistors.
The spin cell maintains a low operating temperature under various levels of sunlight concentration and allows standard mono and poly crystalline solar cells to remain in efficient operating temperatures, even under 30X magnification.V3Solar research continues to determine the maximum level of magnification before solar cell efficiency degrades.Note: All tests were conducted using direct sunlight. Tests conducted by NectarDesign.com
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