This is just my theory.I wnat to know experts opinion on this
LOE e GLASS ROOM SOLAR PNELS
How to increase the efficiency of mass produced solar panels used in India Or How to generate more power from solar panels
The power output of a solar system is dependent on following factors
Location: Your location determines the amount of solar insolation (sunlight falling on the panel per day).We generally receive4-7 KWH of solar insolation per square meter in India.
Orientation: In the northen hemisphere a south facing panel is ideal as sun is always to the south
Panel Efficiency: Efficiency of the panel is calculated as ratio capacity of the panel (KWp) with respect to the size (area) of the panel (m2), expressed as percentage. The table shows the calculation of different panel capacities having the same size.
The efficiency percentage is relevant only to the area occupied by the panel. The lower efficiency panels occupy higher area than higher efficiency panels.
Ambient Temperature: Solar panel temperature is an often ignored but critical parameter in a hot country like India. Panels generates less power in very hot summers as the heat reduces their efficiency (voltage reduces). In Chennai, the month of January delivers better output than May.
Temperature Co-efficient: The rated power of solar panel (e.g 250W)is measured at 25 deg C. The effect of temperature on the solar panel’ power is measured by its thermal co-efficient expressed as %/deg C . A temperature co-efficient of -0.0.447 indicates that every 1 deg increase in temperature over 25 deg C will cause a 0.447%decrease in power. Equally every 1 deg decrease in temperature over 25 deg C will cause 0.447% increase in power. The table below shows the effect of temperature on solar panels when the insolation remains constant at 1000W/m2
So at 45 deg C 250W solar panel efficiency is just 6.53% (15.53% – (0.4520)) and at 0 deg C its efficiency is 26.78% (15.53+(0.4525). Hence solar panels work more efficiently in Himalayas at near 0 deg C compared to Rajasthan’s desert at 45 deg C. But Solar insolation in Himalayas is much lower than that of Rajasthan’s so that will negate the benefit of temperature difference.
THEORY BEHIND THE PRAPOSED LOW e GLASS ROOM SOLAR PANELS
We all know that a typical 250W silicon solar panel has an efficiency of 15.53% at STC. STC (Standard Testing Conditions) means 1000W of sun light hitting the panel of area 1 meter square perpendicularly with cell temperature of 25 deg C , at such time its efficiency is 15.53%. Sun light has primarily three main components visible light(45%) which we can see, Infrared lights (46%) which we feel as heat and remaining is UV light(9%).Solar panels works mostly in wavelength range of 380nm to 750nm which corresponds to visible light range in electromagnetic spectrum. Solar panels converts visible light into electricity (i.e. 45% of 1000W= 450W) remaining IR lights (460W) causes heat in panels and decreases efficiency. So if we could increase the intensity of visible light hitting the panels without letting IR light to hit the plane we could increase its efficiency. We can block IR rays hitting the solar panels without blocking visible light with the help of Low e glass.
LOW e GLASS
IR light is basically heat that we feel when we go near any burning material. When IR rays hits any glass surface it absorbs some portion, reflects some portion and transmit some portion. The absorbed portion is re-radiates from the surface. The ability of material to radiate energy is called emissivity (e). All materials emit heat in the form of IR rays depending on how much they absorbs. The standard glass has an emittance of 0.84 means 84% of the heat energy is absorbed and only 16% is reflected back to atmosphere. So now we have a material called low e glass, it is an advanced glass with emittance as low as 0.04 means it reflects 96% of heat or IR radiation from its surface. Low e glass are used in homes as windows because of its low e properties. Low e glass transmits 60 % to 70% of visible lights and blocks 96% of IR rays.
If we place Low e glass above a typical silicon solar panel with incidence intensity of 1000w per meter square it will block nearly 460W of IR rays and allows 60% of 450W (i.e 270W), due to heat hitting panel is reduced efficiency will increase. Suppose if we concentrate 270W of visible light using lens over a small area then also efficiency increases because area is reduced.
How to use low e glass in open area?
A typical 250W silicon solar panel has an area of 1.61 m2. we have to place this panel in a container made up of entirely of low glass meaning front walls, back walls, sidewalls, roof should be made up of low e glass. Basically a glass room. Temperature inside this container is reduced because low e glass blocks 96% of IR rays. The air inside the room heats ups as it absorbs visible light coming from the inside walls of the room hence if we suck up all air and create near vacuum then due to low pressure, temperature will reduce. If IR exposed glass wall temperature is 140 deg F then inside glass wall temperature will reduces to as low as 93 deg F (See Reference for more Info). A glass structure is made up entirely of Low e material its inside temperature is very low compared to outside.Efficiency is increased just because of temp difference.
If we concentrate ordinary sun light with lens to a fixed point on paper then after few minutes it will burn because it has heat or 46% of IR lights. Low e glass blocks IR rays only transmit visible light so if we concentrate this visible light coming from inside wall of this room to a solar panel it will be used to produce electricity, a small amount may cause heat. The concentration may increase temp but not that much because all of its energy is used in energy conversion. Because of the effect of concentration we can achieve more power. There are practical challenges of concentration but we can find a solution.
If you have a solar park in 1000 acres and if you place Low e glass to cover entire 1000 acre then it will definitely lowers the solar cells temp & increases its power output.
Cardinal Low e 366 is a commercial glass material available in market with 66% of visible light transmittance and 96% of IR reflection.
A.CONCEPT OF LOW e GLASS ROOM SOLAR PANEL
B.CONCENTRATED LOW e GLASS ROOM SOLAR PANELS
C. NON CONCENTRATED LOW e SOLAR PARK WITH GLASS STRUCTURE COVERING ENTIRE STRUCTURE
IF we build Low e glass rooms around a single solar panel in a typical solar park it will definitely increase its efficiency without much difficulty.
Following may be a drawbacks
1.Theorotically speaking Low e GLASS ROOM has the chance to increase the efficiency of solar panels but it is not tested hence do not know the practical challenges
2.LOW e glass materials are costly compared to ordinary glass
3.Visible light transmission is only 66%
4.concentrateing visible light is also a practical challenge
Type in Youtube – Demonstration of Insulating Properties Of Low e 366 glass
- Vaibhav Desai asked 6 years ago
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