Take a moment to visit the PVWatts calculator online for fun. Click “Go” after entering your city and state. Choose the map position that is nearest to your home on the following page, or simply continue with the default location chosen for your city, and then click the orange arrow that says “Go to system info.” Then click the “Go to PVWatts results” arrow on the following page to finish. How much AC electricity you can generate annually at your location with a 4 kW (DC) system facing due south is indicated at the top in large type. The calculator already has the system size and other pre-populated default values.
Even if your system might not be 4 kW or face due south, this 60-second exercise will nonetheless demonstrate how simple it is to start using PVWatts. There is no cost, no need to register, and no advertising.
PVWatts appears to be quite straightforward, but there is a lot more you can do to enhance accuracy. You may simply switch back and forth between the pages, plug in various data, and immediately check the outcomes because it is made for trial and error. Your particular data can be entered on the “System Info” page.
For example, let’s consider we have an average annual energy requirement of 6310 KWhrs/year. Which we calculated earlier. If you want to learn how we have calculated it you can always learn from here.
Now we need to determine the size of our PV array that will be able to meet our annual energy requirement i.e. 6310 KWhrs/year based on a desired location and other factors. For this, we need to put a value in the DC System Size (kW) field of the PVWatts calculator which will return a result of 6310 KWhrs/year. You can always play around with the DC System Size (kW) value to obtain your required annual energy requirement i.e. 6310 KWhrs/year based on your location and other factors.
In our case, our desired location is given below:
In our case DC System Size (kW) value and other considerable values in given as such to obtain our required annual energy requirement i.e. 6310 KWhrs/year is given below. We entered 4.483KW in DC System Size (kW) field and 23 and 205 in Tilt(deg) and Azimuth(deg) fields respectively. Other parameters are kept intact for simplicity.
It is time to get our desired Result
Boom!! we got our desired result which is exactly the same as our annual energy requirement i.e. 6310 KWhrs/year.
The result simplifies the fact that if we have an energy demand for a year is 6310 KWhrs or we need to use 6310 KWhrs of energy for a year then we need to install a PV array having a size of 4.483KW. In other words, a 4.483 KW PV system will provide 6310 KWhrs of energy for a year.