The amount of energy generated is a function of the type of Photo voltaic Panels, the tilt of the panels, the racking type of the PV System,the size of the panels, and the tracking of the sun’s by tilting the panels. This article advises on the types of Photo voltaic panel and related matter about its basis unit of construction and the calculation of the energy generated by panels.
Types of Photo voltaic Panels
Photo voltaic Panels makes use of energy from the sun and the generated energy is called Renewable energy.Typically most of our energy that are generated by the burning fossil fuel. This energy is harmful to the environment. unlike Renewable energy. The use of renewable energy is good clean energy,no harmful by product are produced such as CO, NO 2, SO 2 and dioxin, Dioxin is a very poisonous gas that is detrimental to health. Dioxin is more poisonous that cyanide. Dioxin has a great affinity for animals and water.On in-taking of Dioxin, the Dioxin will remain in their bodies for a long time, as the chemical is a very stable compound.
Renewable energy is good for the environment because there are clean energy and does not foul the air. The total amount of energy that the world consumes per year is only about 0.015 % of the energy that is available in the earth from the sun.
Photo Voltaic system are Grid-Connected where the surplus energy is sent to the grid . The surplus energy is purchased by utility company and on a winter week where there were less energy produced by the system, you may be able to access electricity from the Grid.
There are 4 Types of Photo voltaic Panels(as per NREL of the US)
- Crystalline Si Cells——————–24% efficiency is achievable
- Multi junction Concentrators——-40% efficiency is achievable
- Thin Film Technologies————–18% efficiency is achievable
- Emerging PV————————–10% efficiency is achievable
The attributes of Properties of Types of Photo voltaic Panels
Crystalline Si Cells
There are 2 types of Crystalline Photo-voltaic panels-mono crystalline and poly-crystalline.Both of them are made of silicon crystalline cells. Mono Panels are more efficient than Poly Panels.Poly Panels are less expensive than Mono Panels.They are made of thinly sliced wafers. The types of Crystalline Si Cells are:Single Crystal,Multi crystalline.Thick Si film and Silicon Hetro-structure
Multi junction Concentrators
a) Multijunction Concentrators, are more efficient because the wider spectrum of the light is used for generating energy.
b) Hetrojunction Concentrators, are a hybrid of crystalline and thin film .It is more efficient as it reaps the benefits of crystalline and thin film technology. It is more efficient when the temperatures are high.
c) Concentrating Photo voltaic, are concentrates the photo voltaic spectrum increasing the solar isolation and making the panels efficient.
d) Photo voltaic Thermal, are panels that combines the thermal and photo voltaic energy of the sun to produce energy.
e) The types of Multi junction concentrators are: 3 junction,2 Junction and Single Junction GAas
Thin Film Technologies
It uses low heat and cost lower than crystalline panels.The thin film technology permit the panels to be flexible enough to be used on roofing material. glazing or wall panels. Thin films are more efficient with high temperatures.
The types of Thin film technologies are :Multi-junction poly-crystalline,Nano poly-Si, Amorphous SiH(stabilized),CdHe and Cu(In GaSc2)
Some of the photo voltaic panels which are emerging and may make a difference and become a state of art panel are: organic cells,dye sensitized cells and inorganic cells
Best situations for the Types of Photo voltaic Panels for Maximum Efficiency
- Panels should be tilted to face the sun, or facing south if you are located in the Northern Hemisphere and face north if you are in the Southern Hemisphere.
- Photo voltaic panels on Roofs tops,Car park Coverings and shading louvers reduces the cost of construction.The cost of Roof covering is reduced. The cost of shading devices reduce cost.The cost of roof cover on car parking covers are reduced. Covering of car parking structures help to reduce the heat island effect.
Efficiency of the Types of Photo voltaic Panels
The Photo voltaic solar Panels efficiency ranges from about 20% to 45%, the more efficient the more costly it would be and may make the technology uneconomical or not affordable to use them. we soon found that the most important factor that influences the choice of PV panel is cost and area of space limitation.c) the tilting of the panels
Power generation will defend on the features such as :panels which track the sun,roof installation or open system and the type of the PV panels.
The STEPS for calculation of PV panels sizes is
Following the steps if you are mathematically savvy, otherwise you could seek the help PVwatts supplied by NREL-check it at http://pvwatts.nrel.gov/. The PVwatts calculator assumes a Grid connected system, the Steps below assumes off Grid connection system. The PVwatts calculator will produce the comparative cost savings in the system( over the utility bills) and will consider the technology used (Thin film, Premium, Standard), Racking system used( Roof or Open Rack, axis tracking system,1 axis tracking system or 2 axis tracking system) and the Tilt of the panels.
Step 1 – Calculate the daily energy consumed by the light fitting.
Energy required= Lamp Wattage × Operating Hours per day
= 13 watts × 8 hrs/day
= 104 watt-hrs/day
Step 2 – Calculate the electric energy that the PV panels need to generate.
Assumptions: the battery is 80% efficient and the discharge efficiency is 60%
Energy PV generates = Energy required daily / (Electronics Efficiency × Battery Charge/Discharge Efficiency)
= 104 watt-hrs/day/ 80% × 60%
= 217 watt-hrs/day
Step 3 – Calculate the amount of solar radiation that the PV panels need to collect each day.
ESolar Radiation Needed = EPV Produced/PV panel conversion efficiency
= 217 watt-hrs/day/10%
= 2170 watt-hrs/day
Step 4 – Calculate the average. daily solar radiation at the location of lighting system for the season with the lowest amount of solar radiation
The 30-year-average of monthly solar radiation on a horizontal, flat panel is 2900 watt-hours/square meter/day. And on a flat panel tilted to an angle of latitude plus 15 degrees (facing south), it is 5000 watt-hours/square meter/day, San Diego in December.
Step 5 – Calculate the size of the PV panels required
If the PV panel is in a horizontal position:
Size ,PV Panel = ESolar Radiation Needed/Daily Solar Radiation
= (2170 watt-hrs/day) / (2900 watt-hrs/m2/day)
= 0.75 m2
= ~8.2 sq ft
Plus 15 degrees (facing south) for PV panel tilted at an angle of latitude :
Size ,PV Panels = ESolar Radiation Needed/Daily Solar Radiation
= (2170 watt-hrs/day) / (5000 watt-hrs/m2/day)
= 0.43 m2
= 4.6 sq ft
Guidance to selection of the PV Panels:
The factors one uses to select the panels depends on the following:
a) Space for the panels either on the roof or with the site such as car park sheds or other places, louvers, wall panels etc
b) The amount of energy to be generated
c) The tilting of the panel
d) The tracking system
e) Roof installation or open system
f) The Type of the PV panels
Integration of PV Panels with the Building
The integration of the PV Panels with the building will have make reduce the optimum level of performance of the panels. The panels. Panels performance will depend on its tilt, orientation and the ability to rotate along the seasonal solar path .
PV Panels can be integrated with roof covering( but need to be cautious as working space by the side of the roof and the top has to allowed for future maintenance).Roof top installation of Net Zero Energy achieve the highest categories of Net Zero Classification. The PV panels may replace the Car parking roof covering.This has it advantages such as easy maintenance and accessibility for maintenance. Facades and the louvers of openings can be constructed by PV panels.
Check out our supply cost of (CLICK HERE) PV solar panels
Prepared by Architect Perumal Nagapushnam
System Design Architect