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Tao view the Climate page, click Climate in the main window's navigation menu.
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The Climate page allows you to choose the weather file that Solar Advisor uses for simulations in the current case. The Climate page displays a summary of the weather data, and also allows you to view all of the data in the time series data viewer (DView).
A Solar Advisor weather file is a text file that contains hourly data describing the solar resource at a particular location in one of three formats:
| • | TMY3 comma-delimited text file format (.csv) |
| • | TMY2 non-delimited text file format (.tm2) |
| • | EPW comma-delimited text file format (.epw) |
Files in each of these formats may contain typical year data or data for a single year.
The National Renewable Energy Laboratory's typical year data represents average weather data over a range of years: 1961-1990 for TMY2 data, and 1991-2005 for TMY3 data. Each typical year file may contain data from different years within the range, for example a TMY3 file might contain 1995 data for the month of February, 2001 data for March, 1998 data for April, etc. The NREL typical year data is based on analysis of weather data measured at each location and is appropriate for economic and performance predictions of a project over a long analysis period.
Single year data represents the weather at a location for a specific year. Single year data is appropriate for analysis of a project's economics and performance in a particular year, and for analyses involving rate structure or load data for a given year. Single-year weather data can be developed from on-site measurements or from satellite-derived measurements. The weather files available from the Solar Prospector website using Solar Advisor's Location Lookup feature contain single-year data. NREL also publishes the specific-year data used to develop the TMY2 and TMY3 data sets on its website.
To learn more about the three file formats, and about NREL's typical year methodology, visit the following websites:
Solar Advisor may not be able to read weather files that contain formatting errors or erroneous data elements. In some cases, you can use a text editor to compare a problematic file with one in the same format that works correctly in Solar Advisor to find problems with the file.
The time convention for Solar Advisor hourly simulations is determined by the convention used in the weather data. For example, TMY2 and TMY3 data both use local standard time, and the radiation data values represent energy received during the 60 minutes preceding the indicated hour. The global horizontal radiation shown for hour 1 represents the total radiation incident on a horizontal surface between midnight and 1:00 a.m. of the first hour of the year. Both data sets assume that there are 8,760 hours in one year and do not account for leap years.
Note. You can simulate a system using more than one weather file in a single case by using Solar Advisor's parametric simulation option.
To choose a weather data file:
| 1. | In the Location list, click a file name. Solar Advisor comes with a complete set of the 239 TMY2 files for U.S. locations. |
If the location you are modeling is not in the list, or if you would like to use different data for one of the locations in the list, try the following options:
| • | Use one of the web links on the Climate page to download data from the internet. TMY3 files are available for 1020 U.S. locations and are based on more recent data than the TMY2 data. For locations outside of the U.S., EPW files are available for over 1000 locations in 100 countries. The Solar Prospector website provides access to satellite-derived weather data for the entire U.S. in TMY2 format. You can also use Solar Advisor's Location Lookup feature to download this data by typing a location's address or coordinates. |
| • | Purchase the Meteonorm database and software package, which contains climatological data for over 7,700 global weather stations and can convert weather data between different formats. For a link to the Meteonorm website, see References, Weather Data. |
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Choose Climate/Location
Location
The name of the weather file. A filename preceded by "SAM/" is a standard weather data file included with Solar Advisor and stored in the \exelib\climate_files folder. A filename preceded by "USER/" is a file in a folder that you have added to the weather file search path list.
Add/Remove
Add or remove a folder on your computer from the list of folders Solar Advisor searches for files with the TMY2, TMY3, or EPW file extension. Solar Advisor will list all weather files in folders that you add to the search list in the location list. See Adding and Removing Weather File Search Paths for details.
Refresh List
Refreshes the list of files in the location list. Solar Advisor automatically refreshes the list each time you visit the Climate page. If you add a weather file to one of the folders in the search list, you may need to refresh the list for the file to be visible in the location list.
Copy to project
Embeds the data from a weather file to the project (.zsam) file. This useful when you share your project file with another person and do not want to send the weather file separately. Embedding weather data in a project increases the size of the project file. When you copy data to a project, Solar Advisor indicates the data with "USER/" in the location list. See Copying Weather Data to a Project for details.
Remove from project
Remove embedded weather data. The button is only active when the active location in the location list is preceded by "USER/."
Create TMY3 file
Use the TMY3 Creator to convert your own weather data into the TMY3 format. See Creating a TMY3 file From Your Own Data for details.
Location Lookup
Type an address or coordinates for a U.S. location to download specific-year satellite-derived data from the Solar Prospector website. See Using Location Lookup for details.
Location Information
The location information variables display data from the weather file header that describes the location. An empty variable indicates that the information does not exist in the weather file's header. The location information variables cannot be edited.
City
The name of the city.
State
The state abbreviation.
Timezone
The location's time zone, relative to Greenwich Mean Time (GMT). A negative number indicates the number of time zones west of GMT. A positive number indicates the number of time zones east of GMT.
Elevation (m)
The location's elevation above sea level in meters.
Latitude (degrees)
The location's latitude in degrees. A positive number indicates a location north of the equator.
Longitude (degrees)
The location's longitude in degrees. A negative number indicates the number of degrees west of the Prime Meridian.
Weather Data Information (Annual Averages)
Solar Advisor calculates and displays the annual average of four of the hourly data columns from the weather file in the weather data information variables. Weather data information variables cannot be edited.
Direct Normal (Wh/m2)
The annual average of the direct normal radiation data in the weather file, expressed in watt-hours per square meter.
Diffuse Horizontal (Wh/m2)
The annual average of the diffuse horizontal radiation data in the weather file, expressed in watt-hours per square meter. Note that the annual average global horizontal radiation is the sum of the direct normal and diffuse horizontal components.
Dry-bulb Temp (°C)
The annual average of the ambient temperature data in the weather file in degrees Celsius.
Wind Speed (m/s)
The annual average wind speed in meters per second.
View hourly data
Displays graphs of data from the weather file in Solar Advisor's built-in data viewer, DView. See Data Viewer (DView) for details.
Web Links
Links to websites with weather files on the internet. Each link opens one of three website in your computer's default web browser:
| • | Best weather data for the U.S. (1200 + locations in TMY3 format) takes you to NREL's National Solar Radiation Data Base (NSRDB) page for the Typical Meteorological Year 3 data. |
| • | Best weather data for international locations (in EPW format) takes you to the EnergyPlus weather file page. |
| • | U.S. satellite-derived weather data (10 km grid cells in TMY2 format) takes you to NREL's Solar Power Prospector website. |
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A weather file search path is a folder name and path on your computer that Solar Advisor searches for weather files in one of the three formats that it recognizes: TMY3, TMY2, and EPW. Solar Advisor populates the Location list from the default path and any paths that you add to the path list.
The default path for the complete set of TMY2 weather files included with Solar Advisor is \exelib\climate_files in the Solar Advisor installation folder. Solar Advisor can read weather files stored in any folder on your computer. Because the default location can be difficult to find, if you plan to use weather files other than the default TMY2 files, we recommend that you create an easy-to-find folder to store your weather files. You can then add the location to the weather file search path using the instructions below, and Solar Advisor will automatically find all weather files that you add to the folder.
To add and remove Location list weather file paths:
| 1. | On the Climate page, click Add/Remove. |
| 2. | In the Library Settings window, click Add. |
| 3. | Navigate to the location on your computer where the weather file is stored. |
You can add as many file search paths as you wish.
| 4. | Click Close to return to the Climate page. |
Solar Advisor displays the search paths you added in the Location list.
To remove a search path from the list, click Add/Remove to open the Library Settings window, select the search path and then click Remove. Note that removing a search path does not delete any weather files.
Note. You can also add and remove weather file paths in the SAM Preferences window, by clicking Preferences on the File menu.
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When you want to share a Solar Advisor Model project with another person, and the project uses one or more weather files that the other person does not have, you can include a copy of the data from the weather files in the Solar Advisor Model file. Including weather data in a Solar Advisor Model file increases the size of the file, but also makes it more portable. For example, the size of the photovoltaic sample file with no weather files is 35 kB, with one weather file 274 kB, and with two weather files is 503 kB.
To copy data from a weather file to the project file:
| 1. | On the Climate page, choose the weather file from the Location list. |
Solar Advisor adds the file to the location list with the "USER/" prefix, indicating that the data is included in the Solar Advisor project file. To remove a file from the list, select it, and click Remove from project.
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If you have hourly weather data that is not in one of the three formats (TMY3, TMY2, EPW) that Solar Advisor can read, you can use the Create TMY3 File feature to create your own weather file in the TMY3 format. TMY3 files are comma-separated text files and use the ..csv extension, e.g., my_weather_file.csv.
Note. Unless you have a complete set of weather data for your location that you can use with confidence, using your own data introduces uncertainty into your analysis, and may result in inaccurate results or even simulation errors.
The TMY3 file creator modifies a base file that you specify by replacing only the columns that Solar Advisor needs for simulations. To use the feature, you must have the following:
| • | A base file in TMY3 format to use as a starting point. If possible, the base file should be for the same location or a nearby location with similar weather characteristics. If you have a complete data set that includes all of the columns shown in the table below, then you can use any TMY3 file as a base file. For a link to the TMY3 website and documentation, see References, Weather Data. |
| • | Hourly data (8,760 rows) for each of the data columns shown in the table below. |
The TMY3 file creator replaces columns of data in the base file with data that you provide. If you do not have data for one or more of the columns, you can choose to not replace data for those columns. This will result in a data set that Solar Advisor can read but with mismatched elements that may cause inaccurate results or errors in the simulation.
To create a TMY3 weather file:
| 1. | On the Climate page, click Create TMY3 file. |
| 2. | In the TMY3 Creator window, click Open base TMY3 file, and navigate to the folder containing the base file. |
| 3. | Edit the header fields as appropriate, using the table below for reference. |
| 4. | Open the file containing your weather data. |
| 5. | In your weather data file, copy the column of global horizontal radiation data. Be sure to copy all 8,760 rows of data, but do not include the row header. The column should contain 8,760 rows of numbers. |
| 6. | In the TMY3 Creator window, click the GHI (W/m^w) column heading. Solar Advisor should highlight the entire column in dark gray. |
| 8. | Repeat the copy and paste procedure for each column until you have pasted all of your data into the table. |
| 9. | Click Save as new TMY3 file. You can save it to any folder on your computer. |
| 10. | Click Close to return to the Climate page. |
| 11. | Click Refresh list. Solar Advisor may take a moment or two to refresh the location list. |
| 12. | In the Location list, select the new TMY3 file. You should find it toward the end of the list. |
After creating and loading your weather file, run some test simulations and examine the hourly results to see if there are any problems with the data.
Table 1. Header data for TMY3 weather files
Data Element Name
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Description
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Units
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Site Identifier Code
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A number identifying the location.
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Station Name
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A text description identifying the location.
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Station State
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A two-letter text abbreviation for the location's state.
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Site Time Zone (GMT)
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Time zone of the location in GMT, for example 0, 1, 6, -7, -9.
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Latitude
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Degrees north or south of the equator of the project site. For example, 34.65, -8.0.
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decimal degrees
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Longitude
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Degrees east or west of the prime meridian. For example, -112.42, 1.6.
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decimal degrees
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Elevation
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Location's height above sea level.
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m
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Table 2. Hourly data used for different technologies.
Data Element Name
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Description
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Units
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Date
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Date of current hour.
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MM/DD/YYYY
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Time
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Time of current hour in local standard time.
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HH:MM
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Global Horizontal Radiation
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Total amount of direct and diffuse solar radiation received on a horizontal surface for the hour.
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Wh/m2
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Direct Normal Radiation
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Amount of solar radiation received in one hour within a limited field of view centered on the sun.
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Wh/m2
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Diffuse Horizontal Radiation
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Amount of solar radiation received in one hour from the sky, excluding the solar disk on a horizontal surface.
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Wh/m2
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Wind Velocity
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Average velocity of the wind for the hour.
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m/s
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Dry Bulb Temperature
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Average dry bulb temperature for the hour.
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°C
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Dew Point Temperature
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Average dew point temperature for the hour.
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°C
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Relative Humidity
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Average relative humidity for the hour.
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%
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Pressure
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Station pressure or measured atmospheric pressure corrected for temperature and humidity for the hour.
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mbar
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Albedo
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Ratio of reflected solar radiation to global horizontal radiation. Use -99 for null.
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Solar Advisor's Location Lookup feature allows you to type an address, zip code, or latitude and longitude to download weather data for any location in the United States. Location Lookup uses the Google Maps API Geocoding Service service to identify the geographic coordinates of a location, and downloads data from NREL's Solar Power Prospector database. To use the Location Lookup feature, your computer must be connected to the Internet.
To download data from Solar Power Prospector:
| 1. | On the Climate page, click Location Lookup. |
| 2. | Type a street address zip code, or latitude and longitude, for example: |
1617 Cole Boulevard, Golden CO
80401
39 44 N 105 09 W
35.75 -105.15
Solar Advisor will search the Solar Power Prospector database for a weather file and download it to the weather file folder specified on the Preferences page.
To change the default weather file folder for downloaded files:
| 1. | On the File menu, Click Preferences. |
| 2. | Under Folder for automatically downloaded weather files, type a path name or click  to navigate to the folder. |
Note that the folder for automatically downloaded weather files is different from the weather file search path.
| 3. | On the Climate, page click Add/Remove. |
| 4. | In the Library Settings window, click Add to add the folder to the weather file search path list. |
| 5. | Click Close to return to the Climate page. |
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 | Downloading Weather Files from the Internet |
NSRDB Typical Meteorological Year 3 (TMY3) data: Best data for U.S. Locations
The NSRDB maintains two sets of TMY data. The TMY2 data represent data from 1961 to 1990. The complete TMY2 data is included with Solar Advisor: To use TMY2 data, you simply select a location from the list on the Climate page.
The updated TMY3 data set is based on data from 1991 to 2005. To use TMY3 data in Solar Advisor, you must download the data from the NSRDB website.
To download a TMY3 file:
| 1. | Click the Best weather data for the U.S. (1200 + locations in TMY3 format) link to open the NSRDB TMY3 database page. |
| 2. | On the NSRDB website, click the In alphabetical order by state and city link. |
| 3. | Scroll to the state and city at or nearest your location. |
| 4. | Click the identification code link for the location to download the TMY3 file. |
EnergyPlus Weather (EPW) Files
You can download weather data in EPW format for locations around the world at no cost from the EnergyPlus weather data website at http://www.eere.energy.gov/buildings/energyplus/cfm/weather_data.cfm.
To download an EPW file:
| 1. | Click Best weather for international locations (in EPW format) and navigate to the region and location you want to model. |
| 2. | Download the EPW file for the location you are modeling. |
If there is not an EPW file for the location, download the ZIP file and extract the EPW file.
For some regions, you can download an EPW file directly for a location. For example, for Bangladesh, you can download the data for Dhaka by right-clicking the blue square next to the word EPW for Dhaka. Be sure to save the file with the .epw extension.
For other regions, you must first download a zip file containing the EPW file and then extract the EPW file. For example, for Malaysia, you can download the data for Kuala Lumpur by right-clicking the red square next to the word ZIP for Kuala Lumpur. After downloading the zip file, you can extract the EPW file.
Satellite-derived (NREL Solar Prospector) Weather Data
The NREL Solar Prospector website provides access to satellite-derived data in TMY2 files for specific years between 1998 and 2005 for locations in the U.S. at a resolution of 10 km.
To download satellite-derived data:
| • | The easiest way to download a satellite-derived data is with Location Lookup. You can also visit the NREL Solar Prospector website to download data manually by clicking U.S. satellite-derived weather data (10 km grid cells in TMY2 format). |
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