#1. What should I know about this source of energy?
#2. How the solar cell produces electricity?
1-Crystalline silicon solar Cells:
this First type of solar cell also divided into two main types.
2- Non-Crystalline Silicon Solr Cells
- Amorphous silicon solar cells
for this type Companies refer to it in the datasheet as the following symbol :
A-si thin-film solar module.
A refers to Amorphous.
Si: refresh to Silicon
The two dominating the world market are Poly and Mono, Mono is the richest and the Amorph is the cheapest this is in terms of price, and in terms of efficiency, Amorphous has the minimum efficiency when we compare it with Mono and Poly.
#3.Corporate shortcuts to denote the type of cells
- Monocrystalline, usually companies symbolize it as Mono-Si, So the symbol Si indicates Silicon the material from which the solar cell was made and some times indicate it as Mono or M
- Polycrystalline usually companies symbolize it as Poly-si and some times they make Poly or P
- Amorphous usually companies symbolize it as A-si, and the A indicates Amorphous and si to Silicon.
#4.Fingers and Pasbars
#5. What are the common types of solar panels?
Solar panels are three types that differ according to the silicon cells made of these panels, very briefly and in order to simplify this first issue, solar cells are divided into two main types:
#6. What is the Datasheet and what it contains?
- Cell dimensions with a millimeter (mm)
- The cell efficiency ( less than the efficiency of the panel )
- Maximum Power of the cell
- The cell voltage at the maximum power point (Vmp: when connected )
- The cell intensity at the maximum power point (Imp: when it is connected )
- Open circuit voltage of the cell (Voc: when it’s not connected)
- Open circuit intensity (ISC )
Note: All of these preceding values are given under certain conditions called Standard conditions (1000 watt/m²,25 °c, 1.5 density of atm )
The Power of the panel that the manufacturer of solar panels gives that you find in a datasheet is the maximum power in the standard conditions, and the point that many workers in this field don’t realize is when the company says that the power of the panel is 100 watts, this does not mean that you will get 100 watts during the day. Perhaps you may get 100 watts at ten o’clock and after a minute when a cloud passes, you will get 60 watts and at midday 80 watts and in the evening you get 60 watts good to explain this important point.
#8.VOC, Isc and Vmpp, Impp
Not knowing the difference between the short circuit current Isc and the load circuit current Impp, as well as between the load circuit voltage Vmpp and the short circuit voltage Voc as a result of the wrong calculations of panels and the inaccurate system calculations.
As a final result of the system failure after a while, and a lot of People paid the price of the system twice and three times, and if you go back to the reasons, it will be the result of a miscalculation, which was mainly caused by the lack of knowledge of the difference between the Voltages or currents of the solar panel.
refer to the Datasheet of the solar panel or the inverter.
For more details Read also the 5 parameters of I-V Curve
#9.The Fil Factor
The Fill Factor (FF) is a measure of the quality of the solar cell and it is an important technical parameter to know the quality of the cell and the solar panel in general, This Factor is measured by knowing some of the parameters of the solar panel
It is calculated by comparing the maximum practical power that would be output power to the theoretical power at both the open-circuit voltage and short circuit current.
Voc open circuit voltage
Isc short circuit current
Vmp maximum open-circuit voltage
Imp maximum open-circuit current
After knowing these values from the datasheet of each panel, the Factor is calculated through the following mathematical relation:
The cell quality factor is always smaller than one, and the closer it is to one the better and the meaning of this is that The theoretical values for the amount of energy produced by the cell given by the manufacturer on the dashboard are the same as the values produced by the cell during work, and some companies say that the cell quality factor if it is smaller From 0.7 (70 %) the lower the quality of the cell and the if it is greater then this value the cell is better.
In reality, This will be true, but most solar cell manufacturers have exceeded this number to above this value. to even 0.8(80%)
we can also calculate and know the value of this factor from the IV graph as its shown on the following figure, and you have to know that the IV graph is so important for the engineer.
#10.Moist heat test
what is the Moist heat test?
The moist heat test for photovoltaics is an accelerated environmental aging test that determines the ability of a solar panel to withstand long-term exposure to high temperatures and moisture penetration.
The wet temperature test is performed by applying 85 ° C ± 2 ° C with a relative humidity of 85% for an unbroken cycle of 1,000 hours, which exceeds one month.
1000 hours of wet heat test at 85 ° C and 85% relative humidity equals several years of outdoor exposure. The plate to be tested is placed in a wet heat test chamber where the plate is exposed to these conditions.
#11. What are the defects that can occur during a wet heat test?
#12.Moist heat test and IEC 61215
#12. What type of silicon photovoltaic cells has immunity to the effects of oxygen interaction with boron?
- Silicon photoelectric cells N-Type
#13.One way to protect from hot spots on PV panels
- Is to Use of transit diodes.
#14. What is the most secure type of Solar Inverters?
#15.Which of the following technologies is theoretically the most cost-effective solar PV manufacture?
- Heterojunction solar heterogeneous link technology
#16.What kind of solar panels should be chosen for our projects?
- There is no single answer to this question
#17. What is the highest temperature reached with focused AI technology?
- 1000 ° C.
#18. What does the symbol Class A, Class B, or Class C usually mean on the solar panel datasheet?
- Refers to solar panel’s fire tolerance
Installation of a solar system
#19.Angle and Orientation of the Modules
The angle and direction of each region can be obtained easily through software applications and simulator tools.
for more information about the inclination of modules read this article
#20.The use of completely identical panels in any solar energy project
#21. Does the design of solar panels need an architect and civil engineer ??
#22. Can you place the battery inside the house?
Second, place a cloth over the battery, which is intended to absorb vapors that are dating from the battery. We train the customer to replace this piece every month because it will definitely wear out.
And also make sure that the battery compartment cover contains a hole or hole for leaking gases without causing pressure. And isolate the battery poles in a way that is available to avoid shorts with deformation.
Finally, asking the customer not to approach the system and contact us to do the service at the hands of trained technicians.
#23. What is the effect of the Accumulation of dirt on the solar panels?
24.Variables used to describe the properties of solar cells
#1.I-V Curve Parameters
- Maximum Power at STC (Pmax)
- Optimum Operating Voltage (Vmp)
- Optimum Operating Current) (Imp)
- Open Circuit Voltage ( Voc)
- Short Circuit Current (ISC)
#2.Operating Module Temperature
It expresses the operating temperature at which a solar cell can operate.
#3.Maximum System Voltage
It expresses the system voltage to which a module can be added so that the system does not exceed this amount altogether
The energy conversion efficiency of a solar cell is defined as the percentage of the converted power from the absorbed light when the solar cell is connected to an electrical circuit, which expresses the efficiency of the solar cell, and the more the efficiency of the module increases Which equals
(Generated electric power (Watt) / (Light radiation input (Watt / m2) * Solar cell surface area (m2)
For solar cells, whose efficiency ranges between 16-11%, this means that the cells absorb the radiation coming from the sun And that is 1000w / m2 on a sunny day near the equator, one square meter of these cells absorb radiation according to this efficiency allows between 110-160W.
#5.Maximum Series Fuse rating
It expresses the maximum protection current of the fuse, which the module can handle, and if it increases, it
can affect the solar cells.
The rated power of a cell (Wp) is measured in watts under standard test conditions (STC) Which :
- The value of the maximum orthogonal and instantaneous solar radiation equal to 1000W / m²
- 1.5 AM It stands for air mass (AM) and it refers to how light travels through
- Cell temperature: Tc = 25 C
25.Design & Sizing of an off-grid photovoltaic installation
- The budget: that is to say the financial resources available.
- Definition of the electrical need: By making an inventory of appliances consuming electricity (Lighting, refrigeration, electric heating, household appliances, Television, computers, etc.)
- Assessment of the local solar deposit:: Determine:
- The number of hours of sunshine and the DNI (direct normal irradiance)
- The optimal tilt angle of the PV modules. (Calculated by the formula: latitude of the place + 10 °)
- The orientation of the PV modules: in the northern hemisphere, the full south orientation is the best possible orientation for a photovoltaic field. If we have a choice between the two directions East or West, theoretically it is the same, but it is still necessary to take a look at the needs. Indeed, if the needs are very marked in the afternoon, we will orient the photovoltaic field rather than the West. Likewise, if consumption is higher in the morning, it will rather be oriented to the East.
26.Qualitative parameters of the photovoltaic installation
The yield of a photovoltaic installation expresses the share of energy returned by the installation, in electrical form, compared to the amount of solar energy received by the modules of the installation. Thus, this efficiency is also written: η = (Electric power supplied) / (Solar power received). In addition, it will be necessary to calculate the efficiency of the modules, the losses due to heating of the cables, the efficiency of the regulator, the efficiency of the batteries, the efficiency of the inverter, and other losses.
27.The Quantity of Electricity produced by a PV System
The evaluation of the solar deposit and the quantification of the various losses allows us to calculate the yield of an autonomous photovoltaic installation. Note that the electrical production thus produced is physically adjusted to the consumption of electrical receivers. There is a simple analytical formula for estimating the electricity production necessary for a photovoltaic installation: