You have to design a solar panel to collect light for 5 hrs and used at night for 5 hrs to operate fan of 125 W and two bulbs each 25 W, what should be area of solar panel if solar energy is 1.5 kJ/m² s . Solar constant is energy received by earth per unit area per unit time normal to surface of earth.
Answers
In order to plan a solar power system for your home, you would need to think about the following
Calculate Loads
First, you’ll need to find out how much power you’re currently using. This really comes down to just one figure: the number of Kilowatt-Hours (kWh) that you use each month. One kWh = 1 unit of electricity.
So think of all the appliances that you want to be powered by solar. And find out how much power each appliance consumes in kWh to find out the total load.
Here is an example.
4 tube lights, say each consuming 40 watts an hour. 4 * 40 = 160 W per hour. Lets say you use them for 4 hours per day.
So the total power consumed by the tube lights in 4 hours would be 16 * 4 = 640 Watt hours
2 fans, say each consuming 20 watts an hour. 2 * 20 = 40 W per hour. Lets say u use them for 4 hours per day.
So the total power consumed by the fans in 4 hours would be 40 * 4 = 80 Watt hours
1 exhaust fan, which consumes 20 watts an hour. 1 * 20 = 20 W per hour. Lets say u use it for 1 hour per day.
So the total power consumed by the exhaust fan would be 20 * 1 = 20 Watt hours
2 TV. Lets assume they consume 60 watts an hour. 2 * 60 = 120 W per hour. Lets say u use them for 3 hours per day
So the total power consumed by the TV's would be 120 * 3 = 360 Watt hours
1 Computer, which consumes 70 watts an hour. 1 * 70 = 70 W per hour, lets say i use the computer for 8 hours per day.
So the total power consumed by the computer would be 70 * 8 = 560 Watt hours
1 Big Refrigerator. A modern energy star refrigerator uses less than 100 watts for cooling. So, 100 W per hour.
So the total power consumed by the refrigerator running 24 hours would be 100 * 24 = 2400 Watt Hours (2.4 kWh)
So the total power consumed by the appliances would be
640 + 80 + 20 + 360 + 560 + 2400 = 4060 Watt hours (Just over 4 units a day!)
Calculate Required Solar Input
We live in India, so we get intense solar radiation, lets expect a usable average of around 7 peak sun hours per day.
Required solar panel input = (4060 Wh / 7h) * 1.4 = 812 W
Note: The 1.4 used in this formula is a factor we have found that can be used to simplify the calculations for basic systems.
To ensure that adequate power is produced in the monsoon months, use a figure of around 4 to 4.5 peak sun hours per day
instead of 7.
Select Solar Panels
Select solar panels to provide a minimum of 812 W.
7 x 125 W solar panels chosen which, when connected in series, will provide 875 W
Also remember, the watts on a solar panel is max. watts, this sort of power is created from a panel in a laboratory when they do flash tests on panels. 1000 W of light, under specified conditions. We will almost never get that on any kind of a roof. So select an extra panel for your needs.
Select Inverter
An inverter would take the electrical power produced by the solar panel which is “Direct Current” (DC) and convert it to the form of electricity that your house uses, called “Alternating Current” (AC).
Select an inverter that is more than capable of supplying the maximum anticipated combined AC load required.
So for this setup you will only need a 1000 W inverter.
Select Battery
Battery would be needed if you want to use your appliances at night. Everything you generate during daytime and doesn't get used right away, will be stored in the battery for later use.
A 12 volt 500 amp hour (AH) battery will give us 6000 watt hours worth of energy. Even say at "safe” 70% capacity, we will get approx 4200 watt hours of energy from battery.
So a 12 volt 500 amp hour (AH) battery would do great in this case.
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