 So, let me start we are getting late for the lecture. So, this lecture is about PV system design. PV system design is about you know how to kind of identify the number of components the ratings of a different components in a PV system. So, your PV system design can be very simple and can be complicated. A PV system for example, you may have system which is completely DC based. So, there is no conversion of a DC power into AC power or it can be AC based or it can be a hybrid. So, we are both DC and AC is used and we will look at the design of the PV system. Now, PV system as I told can be very simple. So, you may use a PV panel in a DC fan and put them together. That can be your PV system very simple system adjust a fan and a panel. What will happen in this case and this may be perfectly suited for daytime application for example, as a exhaust fan. What will happen that in the morning your PV power produces less PV panel will produce less power. So, your DC fan will run slowly in the afternoon your PV panel produce more power and your DC fan will run faster and so on. If you do not bother about that fact that your speed of your PV fan can change depending on the input radiation condition, then this system is the perfect low cost system PV panel having a long life and your DC load like a DC motor can also have a long life. And therefore, this system can be perfect. A good example of this system is a solar water pumping a DC motor a brushless DC motor with a pump connected with the PV panel directly can work and can provide you power. But this is the case when you are going to your load will work only when there is a light falling on your module. But if you want to use your load when there is no light falling also then you need to store the energy then your system will look like this. So, your PV panel then your charge controller you are storing energy in the battery and then you are running a DC load. So, this is still a DC system your DC load can be a DC motor it can be DC fan there can there are DC refrigerators available there are DC TV available everything can be DC. So, this is one possible system a DC load can be anything. If you further increase the complication of system you will have AC load also. So, other than the DC load you can say this is the hybrid system you have the charge controller then you have your AC load your converter or inverter then your AC load is there. And in this case the only source of power is PV panel, but if you say you can further complicate the design by connecting your PV system to the grid or you can connect your PV system to the generator which can be a wind generator or it can be a diesel generator and then this can be your system. So, depending on the requirement you can make your PV system very simple or you can make your PV simple system complicated as well. Now, the when you look at the PV system configuration it depends on the many parameters. So, what is your load requirement? What is your resource availability? What is the performance of the system you want you want to extremely efficient system? What is the reliability of the system you want and what is the cost? Reliability means if you are using PV system for hospital application then you want to be 100 percent reliable and therefore, your your system will become little bit more expensive, but if you are using for the lighting application or as a example exhaust fan application and then you do not bother you know if your fan is running slow or fast or if your fan is not running in the night then you do not want that much reliability in the system can be cheaper. So, all these are the parameters which comes to the design also your design can be simple design and or approximate design or it can be precise design for most of the application approximate design will do most of the application if your design is 18 90 percent correct then that is it, but if you are going to do the precise design you require lot of information. So, if you require exactly what is the temperature variation at a given location what is the radiation variation given location if your module is inclined or not inclined if your module is tracking or not tracking what are the parameters of your your module what is the open circuit voltage or circuit current how is the performance varying with the temperature how is your battery and so many so many parameters that will come as a part of the design which will actually give the precise design and in fact when you are putting the megawatts level power plant then you should actually take care of all those parameters and do the real very precise design, but if you are designing a system for home lighting application for example, for your own home or for your college or for your lab then a precise design will do. So, you do not have to really depend real do not have to really go for very detailed analysis of your PV system. So, now as a given you the design of a simple PV powered DC fan this is a very simple example of what possibly can happen in your system. So, look at this is the fan I have shown here the example that the this is a 75 watt module I V characteristic this is a noon time when the and the radiation is higher and this is the morning time this I V curve then as you go from morning to noon your I V curve the current of the I V curve changes voltage also changes little bit this is the performance of the solid line is the I V curve of your module during the day. Now, look at your fan the fan is possibly having a DC motor and this is typically the characteristic of a DC motor this is typically the characteristic of a DC motor. So, where is the operating point operating point is here operating point is here operating point is here operating point is here, but this all this operating points which are shown by the cross are not the maximum power point not the maximum power point. So, your maximum power point is here which is nicely matching with the operating point with the DC fan, but that happens only in the afternoon. At other points, your maximum power point is here, your operating point is here, your maximum power point is here, your operating point is here, your maximum power point is here and operating point is here. So, if you do this connection, what are you going to lose? You are not going to operate your module always at the maximum power point. Then what should I do? Professor Fernandez must have talked to you that what you need to do is you can actually bring in a maximum power point tracking. So, if I go to the whiteboard and explain you that if I am going to use a PV module and if I have a fan, DC fan, one ways to connect them directly, other ways to take a PV module, take a DC fan and in between you use a MPPT, maximum power point tracker. So, you connect this to here and then you connect this to here. The advantage of this kind of system is that it is very simple. There is no electronics and because there is no in between electronics, the cost is also lower. But the disadvantage of this system is that it does not operate always at the maximum power point. So, your maximum power points are here. These are a maximum power point and your load may be like this. So, your power points, your load is not extracting the maximum power all the time. But in this case, because of the MPPT, so your maximum power points are here and because of your MPPT, your operating point will also be here only. So, what you are doing? You are extracting the maximum power in this case all the time. In this case, you are not extracting the maximum power all the time. So, in this case, your performance is low, but your cost is also low. In this case, your performance is high, but your cost is also high. Why cost is high? Because of the extra MPPT component you are ready. So, now as a design engineer, you should make that choice. You should make that choice. Should I use MPPT or should I not use MPPT? Should I use MPPT or should I not use MPPT? And what is the balance? How much extra performance I am getting by putting the MPPT? Now, the example that I am going to take today is actually design of a megawatt grid connected power plant is bit simpler, because there is no battery component that comes in picture. The design of a stained alone system is different. Stained alone system is what? Stained alone means there is no other power source except the PV. So, typically you are going to your SCR DC load, you will you are going to have an energy storage and you are going to your PV module and some electronics. So, that is how the system will look like and how the energy is going to flow. Energy will be generated to PV module through the control. It will go to the battery. It will get stored in the battery and through the battery it will go to the inverter and then go to the load. So, the energy flows like this. So, when we want to design this stained alone system, we need to know everything about load, everything about energy storage, everything about the electronics and everything about the PV module. So, these are the various components we should know about it and design means we should be able to give the specification. So, if you know your load, you should be able to tell this many batteries are required. This much is the rating of the inverter. They should be the input voltage to the inverter. They should be the output voltage of the inverter. This much energy is going inside the battery. This much energy must be produced from the PV module. How many PV modules are required? How many modules are connected in series? How many modules are connected in parallel? All these are the design output that you should bring. Got it? So, when you are saying the design of a PV system means we are actually specifying the ratings and the arrangement of each and every component in a PV system and we are going to look at the design of a stained alone PV system. We are going to look at the design of stained alone PV system. Stained alone means it is not connected to any other source. PV is the only source of energy. So, design means as I said specifying ratings and arrangement. Rating means how much voltage, how much current and arrangement is how many series and how many parallel connections of all components in PV system. Specifying rating and arrangement of all components in a PV system. That is what we need to do in the design and we are talking about stained alone system. So, what are the components there? All the components. So, what are the components that they have? You have PV module, you have a battery, you have a inverter because I will do it for the AC load and may be charge controller or sometime inverter can be a built in function of a charge controller. Charge controller function can be built in inverter and then you should know about your load also. So, these are the things we should worry about. So, normally we do the design in three step and in this case I am talking about the approximate design. So, approximately we should know the sizes. So, we should know first of all determined our daily or we clear energy requirement. Then we should know the, we should design the size of the battery, we should design the size of the PV array and also the inverter ratings. So, now let me do it on the paper white board. I will use most of the white board of from now onwards for the design. So, you be ready with your calculator, those people who have the calculator be ready with your calculator. If not the calculator you can use your mobile. So, first of the thing you need to design, you need to know the load for the design, you should know the load for your design. What are the load components can be? Suppose we are designing it for the home applications, our load will be what? Fan, tube light, TV, computer, refrigerator, etc. So, these are our load. The energy consumed by the load, the energy consumed by the load is determined by the wattage of the load and usage. So, if I am talking about the daily energy, then my usage per day, how much I use per day? So, daily energy consumed by the load depends on the wattage and the usage per day. So, suppose if I am using a, so let me make a small table to calculate the load. So, the name of item which you are using, the number, how many you have and the power rating in watts and then usage per day. So, power into usage per day will give me the energy and if there are more component, I have to multiply by the number of components also. So, suppose let us look at the light. Suppose you have CFL, suppose you have CFL, you have 3 CFL in your house and the power rating of each CFL is 18 watt that is one of the stringer and you are using 5 hours per day. Every day you are using for 5 hours. Good, come here. You are using for 5 hours per day. So, how much this becomes? So, how much this becomes? 3 into 18 times 5, then you are using fan. Suppose you have 2 fan, power of the fan is 50 watt and you are using 8 hours per day, 8 hours per day. So, this calculation, 3 into 18 into 5. So, you will get answer in watt hour per day. We are getting, we are multiplying by watt. This is in watt and this is in hour per day. So, watt hour per day is 270 watt hour per day, then 2 into 50, 100 times 8, then you have 800 watt hour per day and let us take also that you have computer. You have one computer and the power rating of that computer depends on if it is LCD based or let us say you take about 100 watt. LCD based typically can be 70 to 80. Let us take 100 watt and if you are using 2 hour per day. So, then your energy requirement of a computer is 200. So, how much is your total energy required? Total energy requirement is 27800, 1270. So, you require 1270 watt hour per day. What is the unit of electricity kilo watt hour? So, 1270 watt hour is equivalent to 1.2 kilo watt hour per day or you can write here 1.2 kilo watt hour per day. So, basically if this is the condition your daily requirement is 1.2 kilo watt hour per day. So, about 1.2 units you are consuming every day. So, now this is our daily requirement and our requirement daily requirement can change depending on the season, summer it can be different, winter it can be different, but fine approximately I am using 1270 watt hour. So, I am going to design my system for 1.2 kilo watt hour per day or 1270 watt hour per day. Everybody is with me so far. So, by simply putting this watt into watt hour per day, watt into hour per day you can find out how much energy is consumed by your appliance and you can actually add into this list. I have taken a simple list, but you can add into this list fine. So, now 1.270 watt hour per day energy is has to be supplied to the load. So, my load should get 1270 watt hour per day. Who will supply this energy from where this energy will come to the load? Now, assuming that all our systems or appliances in home are AC. So, therefore, this 1270 watt hour per hour should be output of a, it should be a output of inverter. So, my inverter should supply 1270 watt hour per day. What can I tell about inverter? Because all my appliances are we are talking about India. So, it should be a 230 volt AC system. So, my output is 230 volt AC, it should be 50 hertz system. I also need to know. So, this is my output voltage. I also need to know what is the power of this inverter? How much power? What is should be power capacity of the inverter? How would I know? That should have find out from the total operating load at a given moment. How much is the load operating at a given moment? You have 18 watt into 3, 2 into 50 and 1 into 100. This is your load. So, if every appliance is on together, every appliance is on together. How much is the power that you need to supply? Your inverter need to supply. So, total power, your inverter need to supply is 3 into 18, 2 into 50, 1 into 100. How much is this total? 254. So, 254 is the watt that your inverter must be able to supply. This is the worst case when all your loads are connected together. So, your inverter when you go to the market, you will try to find out the inverter which is suited base. So, you might find 250 V A inverter in the market. You may find 250. So, your power rating is 250 V A, your output voltage should be 230 volt AC, your output frequency should be 50 hertz and this inverter should supply 1270 whatever per day. Once you know your output voltage, you can find out what will be the current also. How much current will actually flow in the AC circuit? So, in this way you are defining the output parameters of the inverter. Now, what should be the input? Inverter will take a DC input voltage. So, you must specify the DC voltage. Normally, as I said we want to have the whenever it comes to DC, we want to have higher voltage and the lower current. So, and this DC, the inverter will get its DC power from battery and therefore, battery which you are going to use can be either 12 volt or 24 volt. Let us say I am using 24 volt battery and because inverter to the inverter will come from battery and I am deciding, this is my design. I have decided that I should have 24 volt input supply to the inverter. So, input to now the inverter will have its efficiency. So, this is the power of inverter. Now, inverter efficiency, inverter I will show the efficiency. Let us say inverter efficiency is about 85 percent. A good small inverter will have efficiency about 85 percent. Not good will have efficiency of 75, 80 percent. By the way, the inverters which are used in power plant, actual megawatt level power plant have efficiency of 95, 96 percent. Anyway, so if this is my inverter and efficiency 85 percent, if the energy output from the inverter is 1270 watt per meter square, what should be the energy input to the inverter? Energy input to the inverter should be 1270 divided by 0.85. How much is this? 1270 divided by 0.85, 1494 what should be the unit? Watt hour per day. So, because your inverter is not 100 percent efficient, when it has to supply 1270 watt hour per day output energy, input energy must be 1494 watt hour per day. Now, how do we specify the battery? We specify the battery in terms of voltage and ampere hour. I will come back to that. So, this, I have already decided that the input voltage to the inverter is 24. This is my 1400, 1940 watt hour per day. If I actually divide this watt hour, watt is nothing but voltage into ampere, volt ampere hour. So, if I divide this volt ampere hour by volt, I will get the ampere hour rating of the battery. So, divide this 1494 by 24 and this is voltage ampere hour. I am dividing by voltage. How much, what I am getting? 62.2 ampere hour per day. Ampere hour is nothing but a charge, is a unit of charge. Ampere is charge per unit time and you are multiplying by time. So, ampere hour is a charge. So, my battery should supply 62.2 ampere hour of charge every day. This should be the output of the battery. Clear everybody so far together? Everybody together? So, now, let me go to the battery side. So, I am saying that my battery should supply me, should supply me 62.2 ampere hour per day. Fine. So, should I choose a battery? So, what is the battery voltage? We already fixed and decided. How much? We want 24 volt battery. Now, voltage is fixed. My ampere hour capacity is this. Will this do? Will this ampere hour capacity will be enough? 62.2 ampere hour. Answer is no. Why not? Because the battery has certain characteristic. Battery has one characteristic which is called. By the way, should we discuss the efficiency of the battery at this point? Should we discuss the efficiency of the battery at this point? Answer is not yes. Answer is no. Why no? Because look, when we are discussing the inverter, when we are calculating the energy at the input to the inverter, then only we have taken inverter efficiency into account. So, similarly now, we are discussing output energy of the battery. We should not discuss the efficiency. When we will discuss the input energy to the battery, then we should take care of the battery efficiency. But at this point, we should not take battery efficiency into account. Fine. So, 62.2 ampere hour will not be sufficient because battery has a certain characteristic called depth of discharge. Battery has certain characteristic called depth of discharge or DOD. DOD refers to the percentage of a charge that you can take out from a battery. So, if it is 100 percent depth of discharge means you can completely take the complete charge out of the battery, but that is normally not the case. For example, lead acid batteries are most commonly used and the depth of discharge for the lead acid battery, for the lead acid battery, the depth of discharge is about 50 percent, not every battery. The batteries which are used in the car, for example, are called SLI batteries, starting lighting ignition battery and has a very shallow depth of discharge. You can only take 15, 20 percent energy, but there is what is called the deep discharge battery. Sometimes you see the advertisement such in Tendulkar. Such in Tendulkar is advertising which batteries? I think luminous. Luminous, such in Tendulkar advertised luminous battery and what they say? Deep discharge battery or you can also say tubular batteries. So, they have depth of discharge of 50 percent. So, when you are using or sometimes you can go for lithium ion battery, they have very nice depth of discharge. You can go up to 80 percent. Typically, we use batteries. So, because of the higher depth of discharge, sorry because of the not 100 percent depth of discharge, your battery capacity has to be double because if you have some 100, you can only take equivalent to depth of discharge. So, 62.2 is what I require, but because my depth of discharge is only 50 percent because I am going to use lead acid battery which is normally available and low cost. So, because of that I have to of a divide by the depth of discharge which is 50 percent. So, my actual capacity is now not 62.2, it has become 124.4 ampere hour. My battery capacity is not 62.2 because I have taken depth of discharge into account. It has become 124.4 ampere hour. So, I should use 124.4 ampere hour. Is this going to be sufficient? Answer is yes, but if you want to have certain autonomy. Autonomy is the number of day in which if there is no sunlight, in which if there is no sunlight, you want your system to still operating. If you do not worry about that, this is enough, but if you say no. For two days in the rainy season, even if there is no sunlight, I should get the home appliances running. So, there is what is called the autonomy. Autonomy is the number of days. System should work. Should supply load without sunlight. So, this energy, this will take care of every day story, right? Assuming that your load is also operating in night. So, this take care of every day, but you say if two more days, if I want autonomy of two, if I want autonomy of two days, so your capacity should be for today and two more days. Your capacity should be for today and two days, two days of autonomy. So, that is basically three days. If you want autonomy of two days, your charge storage should be for the three days. One is for today when there is a sunlight and two extra days when there is no sunlight. So, your actual capacity should be if I am taking autonomy. So, remember this number 124.4. So, now considering two days of autonomy, considering two days of autonomy, your battery charge capacity is equal to 124.4 into 3. How much is this? 373.2 ampere hour. So, your battery capacity has to be, your battery capacity has to be 373.2 ampere hour. So, remember where we started? We started that yes, our daily charge requirement is only 62.2, but because my depth of discharge is 50 percent only, I can take only 50 percent charge from my battery. I have to use a battery of capacity 124.4, but because I also want my system to work for two extra days even if there is no sunlight. So, autonomy, then I am actually taking three days autonomy. So, therefore, my battery requirement is 373.4 ampere hour and this charge has to be supplied at what voltage? This charge has to be supplied at 24 volt. So, now you go to the market, you go to the market and you find the battery, typically you will find 12 volt battery, 100 ampere hour capacity, let us say. You are going to the market, you find a 12 volt battery of 100 ampere hour. What is your system voltage requirement? You decided that your system voltage is 24 volt, your battery voltage, your battery voltage is 12 volt and therefore, you need to connect two batteries in series to get 24 volt. You have to connect two batteries in series, fine. What is your total energy requirement? The total energy requirement is 373 and your battery available in the market is 100 ampere hour. You divide 373 by 2.2 divided by 100 ampere hour. So, total you will get about 3.73 batteries. Now, you cannot buy 3.73 batteries, you have to buy 4 batteries. So, you have to buy 4 batteries. So, what is the configuration? You are going to use 2 batteries in series and total you have to have 4 batteries. So, which means you have to have 2 such in parallel. So, this is your battery configuration. This is your battery configuration. So, total output you will get is 24 volt. Total energy stored, how much is the energy stored total is you are having 100 batteries, 100 ampere hour, 4 batteries. So, total energy stored is 400 ampere hour. Your energy, your storage requirement was only 373. So, good enough. How much is the total energy supplied per day by the way? How much is the total ampere hour supplied per day? Is it 373? Is it 373 or is it 124.4 or it is 62.2? How much energy you are supplying per day? Per day you are only supplying this energy 62.2 ampere hour only. All other jamela you did only to store and make sure that it works and you charge. So, actual everyday supply is only 62.2 ampere hour per day. The total charge, daily charge supply is only this much. The daily charge supply is only this much and this is happening at 24 volt. This is how your battery configuration should look like. So, far so good. So, let me now go to the next step. Now, where the energy will come to the battery? See, if I have certain battery system, I am talking about system, where from the energy will come to the battery? The energy is going out to the inverter, but the energy should come to the battery from PV panel or maybe there may be charge controller sitting there. So, that energy should come. How much energy should be feed into the battery every day? This is my battery. How much energy should be fed into the battery every day? It depends on the battery efficiency. It depends on the battery efficiency. If my battery efficiency is, what is typically battery efficiency? Again 80, 85 percent. So, let us take I am taking 80 percent efficiency. If my battery efficiency is 80 percent, the charge output is how much? I am coming back to the energy. The charge output is how much? The charge output is 62.2 ampere hour per day. What is the energy output? 1,494 watt hour per day. So, charge going output here is 62.2 ampere hour per day and this is going at 24 volt. So, what is the energy output? 62.2 into 24. Again I am coming back to the same. Same thing our old number 1,494 is a watt hour or you can say old ampere hour per day is the energy output. Now, energy input, energy input should be higher because, energy input should be higher because of the battery efficiency. I am taking battery efficiency of 80 percent. So, my energy input should be 1,494 divided by 0.80 and you will get how much? 1867.5 volt ampere hour or you can say watt hour. I am writing old ampere hour for some reason I will come back to. But, old ampere hour is watt hour. So, this is the per day energy you should supply into the battery. This is the per day energy that you should supply into the battery. From where this energy will be supplied? This will be supplied from the controller, charge controller and from where energy will come to the charge controller will come from the PV. Now, assume that my control is very efficient. Assume that it is not a bad assumption but, again due to the lack of time I am assuming that assuming my charge controller or sometime instead of charge controller what you will use? You can also use MPPT your maximum power point tracking device. So, assume your charge controller or your MPPT if you are using is 100 percent efficient. If it is not 100 percent efficient you have to divide this number further by the efficiency of their MPPT and you will get the energy that has to be supplied from the PV. But, because it is 100 percent efficient how much energy PV module should supply? How much energy PV module should supply? This much. This is the energy PV module should supply every day 1867.5 volt ampere hour. PV module should supply or generate 1867.5 watt hour or volt ampere hour energy per day. Very nice. So, much energy should be supplied or generated by the PV modules every day. Now, this much energy production will depend on the location. If you are in Srinagar or if you are in Europe your solar radiation is lower. So, more PV modules are required or if you are in Raiasan your solar energy radiation input is higher and less modules are required. What is the simplest? So, you should now know what is the solar radiation at a given location. So, this generation is a location dependent. This is a location dependent. If you are in Jaipur or Karnataka or Maharashtra or Madhya Pradesh that will determine how much energy. So, we should know and remember the very first lecture or the second lecture we are talking about the solar energy radiation available at a given location. So, if you first of all you can calculate that. If you cannot calculate that you can find the various resources on the internet that will give you the approximate amount of solar radiation available to you at your location. Ideally, you are going to install your how to install your module ideally you install your module at an angle tilted equal to what degree equal to your latitude facing south. This is ideally what you want. So, you want your solar radiation available in this plane. You want your solar radiation available in this plane most likely you will not get ready made answer. What you will get? You will get a global solar radiation on a horizontal plane. This is what is normally available, but normally your standard installation is a PV module facing the south tilted at the equal to latitude angle. Anyway, so you get the approximation. So, what I told you this in India the solar radiation available varies between 4 to 7 kilowatt hour per meter square per day kilowatt hour per meter square per day fine. Suppose, I am taking a case of a Jaipur. Suppose, in Jaipur the de Vres solar radiation available is 6 kilowatt hour per meter square per day. If monthly is given or yearly is given you have to divide by the number of days because all my calculation that I am showing you is per day basis. You need to find out if you know the yearly solar radiation in Jaipur you multiply the number of days of the year or if the monthly solar radiation is given you divide by the number of days in a month because all my calculations are on a per day basis. I need to know amount of solar radiation falling on a per day basis. So, I am taking case of a Jaipur which is having 6 kilowatt hour of solar radiation falling per meter square per day. Most likely it is going to be on horizontal plane, but it is this on the on this tilted plane it will be little higher you can do the approximation. Now, my PV module rating is given for what my PV module rating is given for what radiation condition? My PV module rating is given for the power input of 1000 watt per meter square. That is how we characterize my PV module or when you are going to buy your PV module in the market you will get the watt peak rating and watt peak rating is given at the 1000 watt per meter square. Can I correlate this number in this number? Can I correlate this number in this number so that it is useful here? Can I correlate this two numbers so that it is useful here? This number if I this is watt hour per day if I divide this by hour per day then I will get the watt peak requirement. Why hour per day? Because my solar radiation is 6 kilowatt hour per day. So, solar radiation is 6 kilowatt hour per day or I can say it is 6000 watt hour per day or I can say it is 6 hours of 1000 watt per day per meter by this is per meter watt per day per meter by this is per meter square per day per meter square. So, this is per meter square per day. So, I can say my solar radiation is 6 kilowatt hour per meter square per day or 6000 watt hour per meter per meter square per day or 6 hours of 1000 watt per meter square per day. So, my solar my day will be very long in Jaipur you will have the solar radiation going like this. So, in the morning it will have 100 watt per meter square in the afternoon it will go to close to 1000 and your day length may be 12 hours or even longer. But this radiation is equivalent of this radiation is equivalent of this radiation is equivalent of 1000 watt per meter square falling for 6 hours. Getting this point this is the radiation variation in Jaipur morning afternoon evening, but this is equivalent of 1000 watt per meter square for 6 hours both of them are having same energy. Why I am interested in 6 hours of 1000 watt per meter square because I characterize my module I characterize my module for this condition. So, under this condition the output power of a module is given as a watt peak right. So, in Jaipur for 6 kilowatt hour per meter square day my solar radiation is 6 hours of 1000 watt per meter square. So, here my total daily energy requirement as 1867.5. So, my PV module output requirement was 1867.5 watt hour per day and my solar radiation available to me is 6 hours per day right 6 hours of 1000 watt per meter square. So, if I divide this by 6. So, what hour and I am dividing by hours per day both are per day basis. So, this also per day basis. So, what I get? So, I get 311.25 and this is watt and this is not nothing other than this is watt peak because I have taken 6 hours of 1000 watt per meter square. So, actually now my module has to be of 311 watt peak module 311 watt peak module fine. I go to the market I go to the market and I there are there may be many modules available. So, modules that is available in the market is 40 watt peak you will get about 60 watt peak you will get 100 watt peak or 80 watt peak actually and so on. How to choose? If you are going to use 100 watt peak module require about 3 modules and all these modules are at 100 watt peak these are all what is the voltage of all these modules? These are suited for 12 volt supply. These are all suited for 12 volt design for 12 volt and therefore, and because your system PV output should be what? Your PV output should be given to the battery and therefore, it should be 24 volt right you have because your battery is 24 volt. Therefore, I have to have at least 4 modules I have to have at least 4 modules I can let us say I decided to use 60 watt peak module. So, how many modules are required? 311.25 divided by 60 watt peak you get you get 5.18 modules. Now, you have to take a E 1 number because you are connecting 2 in series. So, then you take approximately 6 PV modules. You take approximately 6 PV modules. The 6 PV modules of 6 PV modules of 60 watt peak will give you sufficient power will give you sufficient power 6 PV modules 360 watt peak will give sufficient power. So, what is the PV configuration now? What is the PV configuration? Your PV configuration is your 6 module you have to put again 2 of them in series and there should be 3 such series. So, total output power is 360 watt peak total voltage that you are supplying is at 24 volt actually higher than 24 volt. I am just using the same terminology because the V m maximum power of this voltage will be about 18. So, you are actually about 15 to 16 minimum your supply. So, you will have the higher voltage, but I am using the battery terminology is 24 volt. And total energy supplied every day is minimum 1867 watt per day. This is the energy that is supplied by the modules. Each module is a 60 watt peak module. It module will have it is a V m of about 15 volt and corresponding if V m is 15 volt module output is 60 watt what should be the I m V m equal to sorry P m equal to V m into I m. So, this is 60 watt peak this is 15 then your I m should be 4 ampere. So, these are your module characteristics. So, by doing this now we have almost completed our design. So, we know how many modules we know what is their voltage rating current rating we know how they are connected. We know what is the solar radiation at a given location we have taken the example of Jaipur. And we have taken 6 watt 6 hours per meter square 6 kilowatt hour per meter square per day that give me 6 hours of 1000 watt per meter square out of many modules I have chosen this. You can actually make other choices depending on what is available. Then we have also looked at the solar radiation how to actually make the equivalent solar radiation. Then before that we have looked at Jaipur radiation condition how much energy has to be supplied by the PV module. So, many people make mistake here the energy supplied by the battery is this, but actually at size of the battery is much larger. We take the higher size of the battery because of the depth of discharge and higher and the autonomy, but actual energy supplied is this thus much energy must go input to the battery. And then we have found out the battery configuration inverter size energy input to the inverter energy output to the inverter and so on. So, basically we have done the whole system design we know each and every component we know their power rating we know how they are connected for supplying this much energy every day. So, this is this completes your system design and this system is should going to should be working because you have taken all the necessary things into account. So, let me stop here let me stop here this is approximate design if you want to do the precise design there are many other parameters that must be taken you must take the effect of temperature effect of dust and so on. So, normally you people do little over design little bit over design that you so that you guarantee that even if there are more losses taking place because of temperature because of not cleaning the module regularly and so on your system will still perform as per the design fine. So, that brings me really really really end of the lecture that whatever we could have discussed is here in the slide there are many other thing we do not have time to discuss, but basically this is how that all the design methodology is given. This is the one slide which was missing, but you can see here how the various modules is going to perform. You can see here how various modules going to perform particularly you are interested in the power change. So, power change of cadmium toluide module is here fine. So, that I am that is end of it if there any question there is a PV water pumping system design given in the slide those who are interested can go through it and have a look at it. So, I am stopping here. Thank you very much.