I. Preface Solar power system prices have been high! Mainly because of the low density of solar energy! Sun to the ground, the average light intensity of 1 kW / square meter; silicon conversion rate can reach 23%, up to 16% polycrystalline film can be achieved only 8%. The highest conversion efficiency of GaAs Battery To 35% or more pieces can, however, made with GaAs solar power conversion efficiency of the whole system is only about 25%.
So in order to reduce the price of solar power systems to increase the intensity of sunlight is a good solution, in order to increase the light intensity with a convex lens or a Fresnel lens needed or reflectors to light gathered; This would greatly reduce the use of silicon and gallium arsenide, which reduces the price of solar power generation system; This is the CPV (concentrating photovoltaic power generation system) origin.
2, CPV system of technical difficulties
CPV solar power system principle is simple, why has not the world several companies now make a special power system stable and cheap too! In principle, concentrating on areas of multiple CPV higher cost of the more expensive way, but use of concentrating the following problems occur.
1, to bear the higher silicon condenser times
While GaAs can withstand 1,000 times the light intensity, but now the expensive gallium arsenide, and gallium arsenic is highly toxic and can substantially reduce the manufacturing cost, while in order to Environmental protection Under the theme of the international environment can not be widely used, ultimately, is single crystal silicon; but generally can only afford single crystal silicon 3 to 5 times the light intensity, in the CPV area 3 to 5 times the condenser is almost not very able reduce costs, in order to significantly reduce costs to reach about 10. In order to achieve 10 times the condenser must be specially designed silicon.
2, heat: Ordinary silicon photo Battery Board in the summer noon to 75 degrees above the temperature to ordinary silicon solar panels at twice the intensity of sunlight will be foaming over time, 5 times in 10 minutes under strong sunlight will bubble will, in 10 times 5 minutes under strong sunlight will be foaming, foaming solar cells will be oxidized, in a very short period of time can greatly reduce the efficiency of other post-bubble due to heat unevenly, often burst cells are , so that the system is completely unavailable.
If the solar panels using aluminum or copper heat sinks for natural cooling, massive heat sinks, cost particularly expensive, expensive to more expensive than silicon-rays; If the use of forced air cooling, it is necessary to use large energy losses than gains, and fan life and reliability is not high, in order to achieve high reliability, error checking and redundancy must be set, such as times will increase the cost, if the bad fan in the summer noon, and the silicon solar cell board may be completely burned. If you use water in addition to the use of electricity, the cost is not cheap, water-cooled pipe as more and more connections, but also water Pump , Failure is certainly much worse than the reliability of air-cooled, of course, the efficiency of water than air-cooled, but the failure rate decision solar system is not available.
3, reflectors: Ordinary mirror, Plastic Reflector layer as reflective layer and the skeleton (such as glass) coefficient of thermal expansion and contraction are not the same as 2-4 years in outdoor reflector will fall off in the desert, where temperature differences may be a few months can not use, and the reflection rate slowly decreased.
Addition is also useful at home and abroad with high reflectivity of thin aluminum, but aluminum can not withstand such a hail, and can not be cleaned, if the scrub will have permanent damage, such as aluminum using the 8 year period, and reflective rate decreased year by year, 8 years on the basic rate of only 40% of the reflector, and far short of the requirements of solar system 25 years; aluminum with protective film posted, but the protective film of high cost, not anti-hail, can not solve all the problems . I am a professional writer from China Print Net, which contains a great deal of information about salon sinks and chairs , kid tables and chairs, welcome to visit!
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