Intuitive Application for Solar Panel Electrical Power

Peace be upon you.


Every time we turn on a light, fan we create pollution due to the burning of fossil fuels required to produce that electricity. In 2008, total UK CO2 emissions were 533 million tonnes. 27% of those emissions came from the electricity usage in our homes. It’s clear our homes have a critical role to play in mitigating the effects of climate change. A lovely solar power installation, with its promise of an abundant and clean electricity supply, can save 1,800Kg of C02.


Solar panels can mean big bucks. Photovoltaic panels generate electricity from the sun, and not only do they cut down on your energy bills, you can get paid for generating energy too.

I feel delighted to share with you a highly intuitive application, powered by Google Code; that determines Optimum Solar Panel Tilt angle/Slope (β)  for all Latitudes/Regions, and shows comparison of generated Power for different months, regions, as well as for different panel Tilts(β). 

Intuitive Application for Solar Panel Electrical Power 
http://hatimsolarpanelpower.appspot.com/

The application takes into consideration the Input provided by user
i.e. Total surface Area of Solar used ( sq m or sq feet), and EFFICIENCY of Solar Panel (0-100%)(Eta)

Here Efficiency = Electrical energy (Eo) generated by Solar Panel for every 100 units of Solar Energy (Ei) recieved by it.

Application doesn't take into consideration environmental factors like shading, Cloudiness or rainy season.

Above figure shows two important concepts Tilt angle(β) and Orientation angle.
This application takes into consideration of Optimized Tilt angle(β) while keeping 
Orientation angle as zero. This means Solar panel bottom surface is assumed to be aligned along East-West direction always.

Notice the Figure 1 on Top of this page. it clearly shows how :-

1. Single-axis(E-W axis) tracking system rotates along North-South.
2. Single-axis(N-S axis parallel to Panel surface) tracking system rotates along East-West.

Below figure shows a Sloped roof in higher Latitudes.  For sloped roofs in North Latitudes, the roof facing South would be an ideal candidate for Installing Panels, thereby maximising Power Input to Panel.

As per below figure, which shows Solar declination in relativistic sense.:-

1. For receiving max Solar radiation in Mar, Sep when Solar declination=0, the Solar roof should be (Latitude angle from the horizontal), so as to make Angle of incidence Zero on Panel surface.
2. For receiving max Solar radiation in June when Solar declination=+23.5, the Solar roof should be (Latitude angle - 23.5 from the horizontal).
3. For receiving max Solar radiation in Dec when Solar declination=-23.5, the Solar roof should be (Latitude angle + 23.5 from the horizontal).

The flyer below is an instruction manual for understanding color codes used in application and other informative details.

Key findings from the Solar data calculated from this  application :-

1. Single-axis(E-W axis) tracking system (North-South rotation). produces (~18%) more output power (for Latitudes<50) when compared with a stationary Panel system with Optimized Tilt(β). For Latitudes>50, % gain is 25-50%.
2. Single-axis(N-S axis parallel to Panel surface) tracking system (East-West rotation), produces (~60%) more output power when compared with a stationary Panel system while considering both are @ Optimized Tilt(β) (towards N or S).
   
   Conceptual reason behind above 2 findings, is
   that  Sun's incidence angle (θ)  varies 0 to 90deg ( Panel's N-S rotation) while for Panel's E-W  rotation θ varies 0 to max (Latitude - Tilt(β)). Instantaneous Energy on a panel is Ec * cos (θ(t)) which is higher if θ is close to zero and acute which is true for East-West rotating Panel.
   
3. The gain of output power from dual-axis tracking system is  (~66%) when compared with a stationary Panel system inclined at Optimized Tilt(β).
4. The use of the dual-axis tracking system produces negligible ~5% gain of power output, compared with a single-axis(N-S axis) tracking system (East West Rotation), which is a good learning from economical point of view.
5. At higher latitudes ( Alaska, Norway exceeding 60º N or S), use of dual-axis or single-axis(E-W or N-S rotating)tracking system becomes more economical considering 2-3 times energy produced as compared with a stationary Panel system with Optimized Tilt(β).
   
   Conceptual reason behind this finding is because in the month of May,June, July, it becomes a 24 hour day and a solar tracker(East-West rotating) continuously faces Sun ( in the N as well as S), maximizing the monthly Power input.
   
6. For fixed Panels at lower latitudes ( tropical regions upto 30° N/S), Optimized Panel Tilt(β) is in range of {Latitude-3, Latitude}. 

Calculations method details

The calculations are based upon derivation of formula using concept of relativity (relative velocity and rotation), after years of analysis and knowledge of engineering concepts.  Mathematically, for a particular Tilt(β) of Panel, 
the solar energy at any instant of time is determined by Ec * cos (Incidence angle (t) and it is Integrated ∫ against the total Solar duration on that day. This ∫ is carried out for the entire days in a month and then summed to get Monthly and Yearly
Electrical Power Output. For some of the special Orientations like Single axis Trackers, complex ∫ methods are used using Taylor series or graphical area integration  Σ( E(t) * deltaT)

Based upon considerable testing against available data and real life data, the calculations are expected to be 99% accurate. Based upon feedback or errors reported by readers, the application will accordingly get corrected and updated 
frequently.


Regards
MA Naim


Some quotes by learned people

“We have this handy fusion reactor in the sky called the sun, you don’t have to do anything, it just works. It shows up every day.” –Elon Musk, CEO Tesla Motors

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“Solar is cost effective right now. When you consider the cost to our health from air pollution, solar is just as competitive as any other energy source.” – Thomas P. Kay

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“Because we are now running out of gas and oil, we must prepare quickly for a third change, to strict conservation and to the use of … permanent renewable energy sources, like solar power.” – Jimmy Carter, 39th President of the United States

Useful References

Save the Panet by 12 Energy saving tips http://www.ethicalsolar.org/save-the-planet/save-planet.php

Orientation of solar panels http://solar-trap.com/?p=199

How different angles of incidence of solar rays impact the performance of a solar cell http://www.all-science-fair-projects.com/print_project_1091_96

Sun Angle and Seasons  http://www.geog.ucsb.edu/~joel/g110_w08/lecture_notes/sun_angle/sun_angle.html

Solar Tracker Percentage gains

http://solarenergyengineering.asmedigitalcollection.asme.org/article.aspx?articleid=1662252

Solar Panel -In depth - Solar inverters, MPPT, Efficiencies

http://solarcellcentral.com/solar_page.html

http://www.solar-tracking.com/

Some Solar definitions

Collector Slope, β: This is the angle between the plane of the solar collector and the horizontal. If a panel is lying flat, then it is 0º. As you tip it up, this angle increases. It does not matter which direction the panel faces.

Declination, δ: This is the angle between the line that points to the sun from the equator and the line that points straight out from the equator (at solar noon). North is positive and south is negative. This anglevaries from 23.45 to -23.45 throughout the year, which is related to why we have seasons.

Latitude, φ: This is the angle between a line that points from the center of the Earth to a location on theEarth’s surface and a line that points from the center of the Earth to the equator. This can be easily found on a map.

Zenith Angle, θz: This is the angle between the line that points to the sun and the vertical — basically,this is just where the sun is in the sky. At sunrise and sunset this angle is 90º. At noon it's equal to Latitude angle. 

Solar Altitude Angle, αs: This is the angle between the line that points to the sun and the horizontal. It is the complement of the zenith angle. At sunrise and sunset this angle is 0º.

Solar Azimuth Angle, γs: This is the angle between the line that points to the sun and south. Angles to the east are negative. Angles to the west are positive. This angle is 0º at solar noon. It is probably close to -90º at sunrise and 90º at sunset, depending on the season. This angle is only measured in the horizontal plane; in other words, it neglects the height of the sun.

Angle of Incidence, θ: This is the angle between the line that points to the sun and the angle that points straight out of a PV panel (also called the line that is normal to the surface of the panel). This is the most important angle. Solar panels are most efficient when pointing at the sun, so engineers want to minimize this angle at all times. To know this angle, you must know all of the angles listed and described next.

Hour Angle, ω: This is based on the sun’s angular displacement, east or west, of the local meridian (the line the local time zone is based on). The earth rotates 15º per hour so at 11am the hour angle is -15º and at 1pm it is 15º. Basically, Hour angle varies from -90º ( sunrise) to 0º (noon) to 90º (sunset)

Surface Azimuth Angle, γ: This is the angle between the line that points straight out of a PV panel and south. It is only measured in the horizontal plane. Again, east is negative and west is positive. If a panel pointed directly south, this angle would be 0º. 

Solar Cell Market

In the solar cell market efficiency is crucial to avoid losing market shares on the global energy marketplace. There are two main ways to make solar cells more efficient, either by improving the actual cell or by installing the solar panels on a tracking base that follows the sun.

The end-user will prefer a tracking solution rather than a fixed ground system because:

·         The efficiency increases by 20-60% (= more money) depending on where you are in the world.

·         The space requirement for a solar park is reduced, and they maintain the same output

·         The payback time of the investment is reduced

Our business proposal is to offer a complete linear actuator system that moves the tracking base in your solar tracking system according to the sun. We catch the sun and increase your output of the solar panel.

There are three main Solar Power Technologies:

·         Photovoltaic (PV)

·         Concentrated Photovoltaic (CPV)

·         Concentrated Solar Power (CSP)

 

Photovoltaic (PV)

Photovoltaic power generation is done by employing panels composed of a number of cells containing photovoltaic material (often silicon). This photovoltaic material then converts solar radiation into electric current.

While solar tracking is essential for both CPV and CSP to deliver power it is not the case for PV. The reason for choosing tracking on a PV installation instead of just having a fixed installation is an increased energy output during the day. Whether it is feasible to install a tracker is thus dependable on whether the increased energy output (kWh) weights up the additional cost of the tracking system. Return on investment of the tracking part in a solar tracking system is approximately 4-5 years.

 

Solar Panel Efficiency Most panels are around 11-15% efficient. The efficiency rating measures what percentage of sunlight hitting a panel gets turned into electricity that you can use. The higher the efficiency, the less surface area you’ll need in your solar panels

·         Shade

Basically, shade is the enemy of solar panel efficiency. With poor solar design, even a little shade on one panel can shut down energy production on all of your other panels.