In this video, I want to walk you through

a data sheet of a solar, solar panel, and I’ve just picked

one of these solar panels randomly. So I’ve picked this Panda Series solar

panels which is sold by this company Yingli

Solar. It is one of the larger manufacturers of

crystalline and multi-crystalline based silicon solar panels.

And this solar panel is is made up of these single crystalline, or

mono-crystalline silicon. Okay, so, one thing I should point out is

that these data sheets typically are a couple of pages,

maybe two or three pages. and the first page is always filled with

this marketing information, which I should warn you, you should take it with a

grain of salt. So for example it talks about how much the

installation how much of capacity of modules, this

company has installed. And then it says that you know it can supply these aesthetically pleasing

black modules. I don’t know what, how, you know, making

this thing black instead of of white, would make it more aesthetically

appealing. But they do send to tell, they do tend to

sell like these these modules with, you can choose the color of this plastic

or these [UNKNOWN] sheet, and you can choose it to be either

white or black. The other information that this this data

sheet claims is that this module has the highest

PTC by STC ratio. So, there are two terms over here, one is

STC and PTC. And then there’s a ratio of these two

terms. Wo let me explain now what they, what they

mean. Let me go over here so I can write

some stuff down. So this PTC essentially what it means it corresponds to PVUSA Test Conditions.

And that particular test condition, it essentially corresponds, it

corresponds to having a intensity, having a solar spectrum with and intensity which is normalized

to 1000 watt per meter squared. And you use a AM 1.5G spectrum. And, then you assume that your ambient is essentially you have a temperature, of the

ambient, Is, essentially equal to 20 degrees

centigrade. You assume that there’s a certain, wind

blowing. And this wind is blowing at the rate of one meter per second, which is equal to

2.25 mph. And you know, this was what, this is what

corresponds to PTC. Note that there’s no specification given

on the temperature of the cell. So all you specify is the temperature of

the ambient. And this wind speed. And this wind is also, you know, something

which would, if you have a module like this, and you have a solar

panel placed over here, your wind is essentially, it’s going to be

more effective cooling the panel when it blows at the bottom of

this panel. Because note that this panel essentially

consists of this it, it’s, encapsulated with this glass at the top,

which has a very poor, poor conductivity. So it’s it’s very hard to get heat out or,

you know, convective flow of heat out from the top surface of your

of your of your panel. So I want to state again that there’s no

specification given on the temperature of the cell. So the temperature of the cell for sure would be higher than the temperature of

the ambient, because you have this light with the

intensity of, 1000 watt per meter square shining upon

this panel. And this glass is a poor, poor conductor

of heat, so there’s no way for this heat to escape

as well. Besides from the bottom, if there’s a

wind flowing. So this temperature would be definitely

higher than 20 C. And it would depend largely on these, on

how your module is designed, how efficient your

cell is, and so on. So this PTC rating, or this this power

rating under these PVUSA Test Conditions, it’s usually measured, measured by an

independent body. So for example for the state of California there’s this

California Energy Commission. And they have this website where they measure measure the efficiency of

different modules. Also they list out, they make a list of what are the manufacturer of these

modules, what is the module number, what is it what’s its description,

It is suitable for BIPV? Is it suitable for integration into a building while the building is

being constructed? That’s called BIPV. And then it specifies this PTC rating of

these, of these panels. And this list is updated quite frequently. And the panels which are given in this

list are suitable, you know, California will give you a subsidy if you

use the panels from this list. So let me search for Yingli over here. So Yingli. And then the panel number which I was

using was this 30b panel over here, so I see that it says that you know, it’s it’s made in

China. This is the panel number. Then it says you know, it’s a

Monocrystalline Silicon Module and then it has a PTC rating of 235 watts, so let me

write it down. So this panel. The PTC rating as, as specified by, by the California Energy Commission is,

is 235, 235 watts. Okay. So now what is this STC?

What is this STC over here. So this STC essentially it corresponds to, it corresponds to standard test

conditions. So this STC corresponds to standard

test conditions. And this essentially corresponds to having a

intensity of light. which is again 1000 watt per meter

square and the AM 1.5G spectrum which is

the same as what we used for PTC. But now we give a specification on the

cell temperature and we specify that, it’s, it is 25

degrees Centigrade. And this, this STC test is very often used when these cells are

being manufactured in a line. So one of the steps, that is performed is to generate this solar spectrum using a

solar simulator. And these, measures the efficiency of these cells, while holding their

temperature constant, or, you know, while holding

their temperature to be 25 C. So you know that whenever we operate the

cell, and if we operate it under this, PTC condition, the temperature of the cell will rise because you have this light

shining, and also the cell is, essentially it’s thermally sealed by this glass from the

top. So this efficiency of the cell will, will

decrease as I increase the temperature. So this efficiency will decrease in the

PTC test condition. So that’s why this PTC to STC ratio is

important. And it’s important to find out what is

this PTC to STC ratio. So this STC rating is often given in the

data sheet itself. So I’m going to just look into that. So it says that under standard test, test

conditions, wo the maximum power is for this panel is

270 watts. So, the PTC to STC ratio is essentially 235 divided by, 270.

So this is this is your [UNKNOWN] it’s you know, its let me see, it’s close

to 90% over here. Then it also says that, these, these,

effi-, these panels, they give a efficiency,

these cells which are used in this panel. They give a efficiency of 90 per, of 90%,

but that’s, you know, not relevant. The, what’s relevant is the module

efficiency. And that is given to be 16.5%. Again, the thing you should be asking

yourself is that under what what what kind of test conditions is

this efficiency measured? And so it has you know, some other, other

marketing information such as it uses anti-reflective coating,

that it specifies what kind of warranty is available on

these panels. And then what certification and these

what quality certifications it has passed. So for example to, to operate them in California a very important certification

is this CEC certification. Which is the California Energy Commission.

So now, the, let’s come to the second page of this data sheet.

And this is where most of the meat or most of the information which makes a

electrical engineer’s heart sing, or even a mechanical engineer’s heart sing,

lies over here. So, as soon as, you know, I look at some,

of these metrics, I recognize, some of the

terms that I have learned. That is, I recognize my efficiency over

here. I recognize my, power max point, my

current max, open circuit voltage, short circuit

current. So these are things, you know, I’m very

familiar with. And, again, I note over here that this are

specified in in for a, for two cases. One is a standard test condition.

And if you read the footnotes over here, they say again that, that standard test

condition had corresponds to 1000 watt per meter square with a cell held at a temperature of 125

C, and the AM 1.5 G spectrum. Another thing to notice is that there are these

different columns over here. And they have, you know, they have very similar similarly lettered names, but you

see over here that the efficiencies of these are

different and they’re varying by you know, varying from

all the way from 16.5 to 15.3. So what have what have been done over here

is that they all use the same cell. But the highest efficiency cells have been

binned over into this module which has the highest

efficiency of 16.5. And all the bad cells, you know all the

black sheep in the, in the manufacturing line, they have been binned

over into this particular module which has efficiencies of 15.3.

But, from a manufacturing process or from a cell perspective, they came out,

all from the same manufacturing line. Okay? So, another thing I notice is my open

circuit voltage and I notice that this is equal to 39

volt. And then the next thing I’ll check is how

many, how many cells I had. So let me count the number of cells, so 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

and then I have six, six columns of these ten cells.

So total number of cells I had was around, or not around

but exactly 60. So for 60 cells, I get a open circuit voltage of 39 volt, assuming all of them

are, all the cells in a panel are connected in

series. This corresponds to a Voc of each

individual cell to be approximately 39 by 60 or approximately 0.65 volt. That’s the Voc of my, one, one of these

silicon cells and that sounds approximately right

given that these are made out of silicon. So another thing to notice over here is

this these, some of these metrics are also reported for this nominal

operating cell temperature. So these the STC conditions, they

corresponds to a cell temperature of 25 C. But there’s this also, this nominal operating

cell temperature. Which essentially you know it’s similar to the PT, similar to

the PTC condition. But it uses it uses a irradiance of 800 watt per meter squared instead of 1000 watt per

meter squared. Again 20 degrees centigrade ambient, and one meter per, one meter per second

speed. So the cell will essentially rise up, in

temperature. Typically for these,

crystalline-silicon-based, based cells, it can, vary all the way from, you know, the

cell temperature for this particular ambient condition in this area, irradiance, It can

vary all the way from 40 degrees C to all the way up to 70 degrees C,

depending upon depending upon how good is your, how good is your module design to

carry away this heat. And also it depends upon what is your

irradiance level as well. So again, at some of these these nominal

operating test conditions so they spec, specify some of these metrics for these conditions

otherwise. And then another important metrics to is to

note is specified in this table over here, where it gives a temperature coefficient

of of my power, the temperature coefficient of my voltage,

the temperature coefficient of my current. So I notice that as I increase my temperature,

my Voc decreases as as I increase my temperature because my Voc has

a negative coefficient over temperature. So, it decreases by 0.31 percentage

points. So, these things are reported by

percentage points per degree centigrade. So if I increase my temperature by one

degree centigrade, this Voc will essentially decrease by 0.31%.

Similarly, if I increase my temperature, my short circuit current typically

increases. Because my bandgap of my solar cell decreases. So my short circuit current increases, so this has a positive temperature

coefficient. The overall power of my cell essentially

decreases, and you can see that my power decreases with this negative temperature

coefficient of 0.42%. Sometimes these, they also specify the nominal

operating test conditions. So they say that if you do operate the

cell at this irradiance level of 800 watt per meters square. And this is the temperature of the ambient

and the wind speed, the temperature of the cell is going to be

between 46 plus, minus 2 degree centigrade, so it’s going to operate

between 44 to 48 degree centigrade. So these are some of the things to keep in

mind. What we need, what we desire for is a good PTC

versus STC ratio. And also low cell operating temperature, because

the higher the temperature the cell will operate at, the more would be the efficiency

degradation.

liX wI am sure you can still buy handbook with all info you need on INPLIX. Just google it.

I made it myself. Just go to Inplix webpage if you'd like do the same

Excellent explanation! …thank you.

good job very useful content..but your English is hard to understand