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To view the PV Loads page, click PV Loads on the main window's navigation menu. Note that for the PV Loads page to be available, the technology option in the Technology and Market window must be Photovoltaics - Component-based Models or Photovoltaics - PVWatts Performance Model.
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Note. Solar Advisor's load feature is currently under development. The simple implementation is intended for testing purposes. Feel free to experiment with the feature. If you have questions or feedback about modeling loads in Solar Advisor, please contact Solar.Advisor.Support@nrel.gov.
The PV Loads page allows you to define an electric load for a grid-connected photovoltaic system with storage. When you define a load for your system, you should also define a storage system on the PV Storage page. A load data set must consist of 8,760 hourly average demand values in kilowatts, representing the electric demand of a building or other load center for a single year.
When you have defined load data, Solar Advisor displays the mean, minimum and maximum values from the data set in the small box next to the Edit button.
The following information will help you experiment with the loads feature:
| • | You can use load data stored in a text file, or use the Edit Hourly Data window to create a load data set from data in a spreadsheet or other file, or by defining a set of daily load profiles for each month of the year. |
| • | Solar Advisor comes with a set of load data files for several cities in the United States. The files are located in the \samples\Residential Load Data folder. |
| • | The PV load feature works in conjunction with the PV Storage model. Solar Advisor only uses load data when the total battery capacity on the PV Storage page is greater than zero. |
| • | The load data appears in DView as "P_LOAD," and on the hourly tab of the results workbook as "Load Demand (kWh), Hourly." |
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You can use one of the load data files supplied with Solar Advisor, or prepare your own load data file.
A load data file is a text file with 8,761 rows: The first row is a text header that Solar Advisor ignores, and the remaining 8,760 rows must contain average hourly electric demand data in kilowatts. The first data element represents the hour beginning at midnight and ending at 1 a.m. on January 1.
To import load data from a properly formatted text file:
| 1. | On the PV Loads page, click Edit. |
| 2. | In the Edit Hourly Data window, click Import. |
| 3. | Navigate to the folder containing the load data file and open the file. To use U.S. load data supplied with Solar Advisor, navigate to the \samples\Residential Load Data folder. |
Solar Advisor displays the data in the data table. Use the scroll bars to see all of the data.
| 4. | Click OK to return to the PV Loads page. |
To import load data from a spreadsheet or other file:
| 1. | On the PV Loads page, click Edit. |
| 2. | Open the spreadsheet containing the load data. The data must be in a single column of 8,760 rows, and expressed in kilowatts. |
| 3. | In the spreadsheet, select the load data and copy it. |
| 4. | In the Edit Hourly Data window, click Paste. |
| 5. | You can also copy data from the Edit Hourly Data window by clicking Copy, or export the data to a text file by clicking Save. |
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If you do not have a complete 8,760 set of load data, you can use a set of daily load profiles for each month, and use Solar Advisor to create a set of 8,760 values.
To create a load data set using daily load profiles:
| 1. | On the PV Loads page, click Edit. |
| 2. | In the Edit Hourly Data window, check Use monthly grid to generate 8760 data. |
| 3. | For each month of the year, define a daily load profile by typing a kilowatt electric demand for each of the 24 hours of the day. The first column represents the first hour of the day, beginning at midnight and ending at 1:00 a.m. |
If you want to specify separate load profiles for weekdays and weekends, click Weekend Values to define profiles that apply to two days each week. Solar Advisor arbitrarily assumes that the first day in the data set is a Monday, and that weekends fall on Saturday and Sunday.
If you do not specify separate weekend profiles, Solar Advisor applies the weekday profile to all days of the week.
| 4. | When you have specified all of the daily load profiles, click To 8760 to transfer the data to the User Specified data table. You must complete this step for Solar Advisor to use the profile data in simulations. |
When you define a load with daily load profiles, Solar Advisor assumes that all days in a given month have identical load profiles.
| 5. | If you want to export the 8,760 data to a text file, click Save. You can also copy the data to a spreadsheet or other file by clicking Copy, and then pasting the data in to the file. |
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