Note to the reader:
V3Solar’s™ engineers had been asked to provide a web document that would provide the reader with an understanding of the outcomes and benefits that can be achieved by using Dynamic Spin™ Technology. This document attempts to provide the reader with as much information as possible without having a formal NDA or an agreement in regards to intellectual property ownership and its control in place.
If you are a manufacturer or a party that is interested in potentially licensing our technology, then under formal agreement as to IP rights and control we will provide further in-depth information on our patents, various documents that explain the design of the electronics that manage and harvest the energy produced through Dynamic Spin™ as well provide details of various unique design elements that can be deployed to maximise energy outputs and reduce the overall cost per watt when compared with current solar panels.
Dynamic Spin™ based products will provide the global energy market with its first real alternative to solar panels and allow for a range of distinctive designs to be developed to suit the needs of various markets needs throughout the world . Dynamic Spin™ can also provide the manufacturer with a sustainable competitive point of differentiation and unique product advantages for their markets.
V3Solar’s Dynamic Spin™ Technology dramatically improves the performance of one-Sun PV by :
a) Utilizing a periodic concentrated light pulse.
b) Rotating PV around a central axis.
c) Proprietary electronics intelligently manage DC or AC power.
Designing one-sun PV to propagate in and out of concentrated sunlight offers three main advantages :
1) A reduction of heat that is normally generated when PV is subjected to a concentrated light source.
2) The energy produced by the rotating PV generates pulses of power that are predictive, and can be
intelligently managed by power electronics to maximize performance.
3) Managing heat and energy provides :
a. Higher levels of PV efficiency and energy output.
b. Substantial reduction in the quantity of PV required.
c. Reduction in the overall cost for a given energy output.
Dynamic Spin™ technology is classified as a mid-level concentrated photovoltaic system (MCPV). The technology’s design advantages allow for flexibility in application, scalability, and cost benefits. Dynamic Spin is designed to maximize performance of any off the shelf one-sun PV. V3Solar™ technology improves performance of standard .5-volt mono/poly solar cells to miniaturized solar modules offering voltages up to 6 volts under load. (Pmpp [V])
Dynamic Spin™ Technology of photovoltaic cell output evolved from the two-year study of the dynamic nature of solar cells individually producing power in a periodic state. Dynamic Spin™ Technology utilizes periodic illumination of PV cells under concentrated light to achieve improved cell efficiency, and power output.
Typically PV cells are modeled as a light-proportional current source in parallel with a diode, along with shunt and series resistances, as shown in Figure 1. While shunt and series resistances are noticeable energy losses, the diode represents the dominant energy loss. Dynamic Spin™ Technology is designed to minimize this loss, and to maximize energy production and efficiency.
Figure 2: PV cell current vs. voltage at 1-sun insolation
Figure 1: 1-diode model of PV Cell
Figure 2 shows the current-voltage curves of a cell in which the shunt resistance is assumed infinite (not present) and the series resistance is assumed zero (ideal). The blue line shows the current produced by the current source as a function of cell voltage with 1000 W/m^2 insolation. Note that the current produced is independent of cell voltage. This means that current source power output, which is the product of current and voltage, increases in direct proportion to cell voltage without limit. This is of course, an artifice of the model; the current source never exists independent of the diode element, which limits operating voltage.
The green line shows the current through the diode element of the model. Note that the diode conducts essentially no current below 0.4V. Above that voltage, the diode current grows exponentially. By 0.63V the diode is conducting all the illumination current resulting in a net cell output (dashed red line) crossing zero.
Figure 3: Cell power output vs. voltage
For later reference, the cell power curve is presented here. Multiplying the net cell current data in Fig. 2 by the cell voltage yields the cell power output shown in Fig. 3. Note that the drop-off in net cell current caused by the diode element results in a distinct peak in cell power output: about 20 mW/cm2 @ 0.51V.
How does light concentration improve PV performance?
Because the current lost through the diode is only a function of voltage, it does not increase with increased illumination. Figure 4 shows the output of the same cell in Fig. 2 with 10 suns illumination. Note that in comparison to the data in Fig 2., the diode current seems almost negligible. This is a relative effect, the diode curve is still the same, but illumination current is now 10 times greater. As a result, the cell can be operated to higher voltage before diode current limits power output.
Figure 4: PV cell current vs. voltage at 10-suns insolation
Figure 5 shows the power curve of the cell operating at 10 suns insolation. Note that compared to the data in Fig. 3, the peak power now occurs at 240 mW/cm^2 at 0.61V. Where insolation has increase 10x, peak power output has increased 12.1. A 21% increase in efficiency.
Figure 5: Cell Power output vs. voltage a 10-suns insolation
The design constraint with static concentration of light
Figure 6: Typical PV cell IV curve degradation with temperature
While concentrating light results in increased PV cell efficiency, it also increases cell heating. Since the diode current increases with temperature, cell heating can easily eliminate the gains achieved from increased concentration. Figure 6 shows the effect of temperature on a typical PV cell. If a 10x increase in insolation results in a 50°C rise in cell temperature, there is no net gain in cell efficiency.
V3Solar™ has resolved the heat constraint of static concentration by utilising Dynamic Spin™ Technology. Cell power production is a near instantaneous process while cell heating is a relatively slow process. By rotating the cells through the concentrated light, the cells operate at high efficiency while illuminated, but their temperature is no higher than under steady non-concentrated illumination. By connecting solar cells in parallel, and rotating them through the concentrated light, the sum total output is a continuous waveform.
V3Solar™ has fixed this inherent design attribute of all solar cells when in a “dark” state by the nature of spinning the cells in and out of concentrated light. Solar cells in a dynamic state create a predictive power output signature that can be efficiently managed for maximum total output power.
Figure 7: Power Management Circuit
What is the heat reduction factor when rotating PV about an axis?
Currently we achieve a 10:1 reduction factor from static to dynamic heat coefficients. The research V3Solar™ engineers conducted involved a series of tests to discover the minimum RPM required in order to maintain peak performance of the cells relative to optical concentration levels. We discovered mathematical, and geometric relationships based upon the following criteria:
- Ambient temperature
- Number of solar cells
- Diameter of rotating hub
- Material of rotating hub
- Concentration factor
Figure 8: Chart predicting heat reduction factors based on ambient temp, hub material, and concentration factors.
Figure 9: Projector physics in cooling film is the same physics as in Dynamic Spin™ Technology
For explanation purposes one can compare the heat reduction properties of a movie projector to V3Solar’s Dynamic Spin™ technology.
Light bulb temperatures in a movie projector were measured to reach 371°C, 3 centimeters from the high intensity light bulb (concentrating light in our case) is the film gate.
The temperature of the moving film (rotating PV about an axis in our case) measured at 21°C. When we turned off the film motor so that the film stops in front of the film gate with the high intensity light on, the temperature of the film increased to the point the film melted at 71°C.
This is an accurate comparison to a technology that utilizes movement of a medium to prevent the absorption of high temperatures.
V3Solar™ laboratory test station
Our laboratory Dynamic Spin™ test station allows for the testing of various solar cells and PV modules. The unit’s center axis holds 4,6,8, and 12 cell hubs. For these particular tests we used a four-sided aluminum alloy hub. Affixed to the four sides are 4 IXYS 4.5 volt solar modules. Each module is wired individually via a Mercotac slip ring to our proprietary power electronics board. Opposite to the power electronics and mounted on a rotating plate are data acquisition electronics to monitor heat from various points on the hub as well as other performance criteria.
Figure 10: V3Solar™ lab test station
Figure 11: V3Solar™ lab test station
Figure 12: Data provided by solardat.uoregon
Tests conducted at a latitude of 42.2400° N, Longitude of 122.7822° W.
At the time of testing direct normal solar irradiance levels at 14 :22 was 920 W/M^2
Figure 13: Thermo-sensor locations
Four OMEGA precision fine wire thermocouples were utilized for measuring inner and outer surface temperatures:
TC1, and TC4 measured surface temperatures.
TC2, and TC3 measured internal temperatures
Defining heat absorption coefficient
Figure 14: Dynamic temperatures max = 42° C Figure 15: Temperatures on stationary cardboard = 427° C
It is important to note that heat coefficients will vary based upon shape, size of hub, and type of materials utilized.
Defining performance gain coefficient
Figure 16: One sun performance Figure 17: 25X performance
Calculations performed by V3Solar™ have indicated PV cell efficiency can be increased by at least 25%. The two primary objectives of the test apparatus were to evaluate the degree to which efficiency increases can be realized and research increasing light concentration factors.
Increased efficiency is estimated via measurement of short circuit current and peak power point. Assuming a consistent quantum efficiency of the PV cells at short circuit conditions (conversion of photons to current), the increase in short circuit current is a measure of concentration factor. The increase in conversion efficiency with concentration is then the ratio of peak power increase divided by the short circuit current increase. For example, a 13x increase in peak power with just a 10x increase in short circuit current would indicate a 30% increase in efficiency (13x/10x – 1).
An advantage of this approach is that it separates optical efficiency (short circuit current ratio) from overall conversion efficiency conversion efficiency (peak power ratio), which is useful in understanding overall system performance. The automated IV curve tracing system allows these measurements to be measured with and without light concentration.
The second objective of this testing was to increase light concentration. The primary concern of concentrated light operation is overheating of the PV cells. The cell rotation and its relationship to the size of the hub helped to mitigate the higher energy input by increasing the convective heat transfer coefficients. The temperature measurements taken during testing allowed heat transfer coefficients to be estimated and observed how they are correlated to rotational speed.
Multi Junction PV
A research and development project is currently being devised and costed to determine the optimum way to configure and test a Dynamic Spin™ based system using multi junction PV. When our performance outcomes with industry standard PV are repeatable with multi junction PV, then substantial breakthroughs in performance and pricing for a multi junction PV based solution will be achieved.
We will document our findings and publish them on this website from time to time. If you are a subscriber to our newsletter you will be also be kept abreast of our progress with this exciting new phase of development for our Dynamic Spin™ technology.
Dynamic Spin™ Technology in its application with current CPV systems provides a cost effective cooling solution outperforming conventional methods of active cooling as current CPV systems require elaborate cooling systems to maintain optimal operating temperatures.