Weather Station Manager: Overview & Setup

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This topic provides an overview of the Weather Station Manager, which provides an interface for assimilating weather data for use in EnergyCAP Enterprise. Weather Station setup information (automatic and manual) is also provided.

Weather stations are logical devices used to capture and measure atmospheric data that can be correlated against usage or demand. Weather stations are similar to meters and counters. As with meters and counters, weather stations have channels for each specific weather condition tracked. Temperature, humidity, dew point, cloud cover, and wind speed are only a few of the types of conditions that can be tracked by weather stations.

Weather data can be provided through our weather subscription service or by your organization. For more information on importing weather data, please see Importing Weather Data from Weather Subscription Service or Importing Weather Data from Other Sources.

Creating and Assigning a Weather Station Automatically

The Auto-Assign procedure can/should be performed whenever new buildings are added to the organization. The Auto-Assign feature does not affect buildings with weather stations previously assigned.

NOTES: Automated weather station processes are functional only for EnergyCAP clients using the weather subscription service.

Make certain that all Places to be updated have been assigned a valid POSTAL (ZIP) CODE in the place Address (see Place Properties, General tab) prior to performing the procedure below. No additional address information is required.

Navigate to Setup > Weather Stations
Click the Auto Assign button from the Weather Station Manager title bar.

The Auto Assign... window will appear.

Any ZIP codes for buildings which do not currently have a weather station assigned will appear in the list.
Click the Find Stations button. EnergyCAP will automatically check the online weather service database for the listed ZIP codes and populate the weather station code, city, state, and country for the listed regions. Any places with ZIP codes that do not match the database will not be linked to a weather station.
After the list is populated, click Assign to Buildings. Any stations that do not currently exist in the EnergyCAP database will be created and then assigned to buildings with that ZIP code. If multiple ZIP codes share a station, only one station will be created and all buildings with all ZIP codes that link to that station will be assigned to it.
After weather stations have been assigned, click Close. If desired, download associated weather station temperature data when prompted (Import Readings). All daily data dating back to 1995 will be downloaded. With multiple weather stations, this process may take an hour or more when it is first performed. Thereafter, only recent data will be appended.

Editing a Weather Station Assignment Manually

To change the weather station for a building:

Open the Facility Manager (Setup > Facilities).
Select the desired Place from the Facility Manager hierarchy.
Right-click and select Place Properties. The Place Properties window will open.
Click the General tab.
Click the Weather drop-down box and select an existing weather station from the drop-down list.
Click OK to save the changes and exit the Place Properties window.

Creating a Weather Station Manually

The first step in tracking, charting, reporting and analyzing weather data is to create a weather station. To create a Weather Station manually:

Navigate to Setup > Weather Stations
Click the New Station shortcut button to create a new weather station record.
Enter a Station Code and a Station Display Name. The Station Code does not have to coincide with an established airport or city code.
Enter the Time Zone (This is only used to synchronize weather data and/or interval data when charting data from different time zones.).
In the upper right corner, select one of the three tracking options. Most EnergyCAP users simply track mean daily temperature. Mean daily temperature is the average of the daily high and the daily low. A day with a high of 80 and a low of 50 has a mean of 65. Typically, the mean temperature will be experienced between 10 and 11 am. In other words, on a day that has an overnight low of 50 and a daytime high of 80, the mean temperature of 65 will occur around 10-11 am.

It is possible to track the mean daily temperature in degrees F or degrees C. However all data distributed via the EnergyCAP weather data subscription service is in degrees F. This includes Canadian stations.

To track temperature data on an interval other than daily (e.g. hourly) or to track weather data variables other than mean daily temperature (e.g. humidity, wet bulb temperature, wind, sunshine, precipitation, etc., create one or more data channels (see Creating Weather Data Channels).

If you have chosen Mean Daily Temperature, a Mean Daily Temperature data channel will be created for you when you click OK.

Beginning with EnergyCAP rel 5.0, you can automatically import weather data that has been provided by AccuWeather.com.

You must subscribe to this service and a low annual fee applies.Your subscription is for a set number of weather stations.If you have subscribed to the service, enter the state/province in the first data field and enter the specific city or airport in the second.The weather code identifier shown in the second field does not have to match the code you gave this station in the Code field.

Checking Weather Data for Missing Values

With many weather stations and many years of data it can be difficult to ensure that no daily data is missing.Therefore, use the Check Data shortcut button to identify:

The first day for which weather data exists (first observation)

Any missing days within the designated range of Check dates.

Degree Days

EnergyCAP uses mean daily temperature to calculate daily degree days.

A degree day is a measure of relative heating and cooling energy required by buildings. It's calculated as the difference between the average daily temperature and the balance point temperature (55 degrees). When the average daily temperature is above the balance point, the result is cooling degree days; when below, the result is heating degree days.

Example 1:

Average daily temperature = 80. Balance point = 55. Cooling degree days = 25 CDD. (80-55=25)

Example 2:

Average daily temperature = 40. Balance point = 55. Heating degree days = 15 HDD. (55-40=15)

Example 3:

Average daily temperature = 55. Balance point = 55. No degree days.

Why not use average temperature instead of degree days? The problem with average temperature is that highs and lows cancel each other out. A warm day (75 average temp) combined with a cold day (35 average temp) average 55. So do two mild days of 56 and 54. But in first case there are 20 CDD and 20 HDD while in the second there are 1 CDD and 1 HDD. Using degree days, you can see that the relative amount of energy required for the first set of days is much greater than for the second set of days. But if all you looked at was the average temperature, you would conclude that both sets of days were about the same.

The balance point temperature is the average daily outside temperature at which a building maintains a comfortable indoor temperature without heating or cooling. At this outside temperature, the indoor heat gains (due to people, lighting, equipment, etc) "balance" with heat loss through windows, walls, roof and ventilation.

Since the average daily outside temperature normally occurs at about 11 am, here’s the question: On a typical day, if the outside temperature at 11 am is 55, is the building being heated, cooled or neither? If heated, then the balance point should be set HIGHER than 55; if cooled, then the balance point should be set LOWER than 55; if neither, then a balance point setting of 55 is appropriate.

The 65-degree balance point standard was developed 75 years ago to help the gas industry predict heating loads in residences. Studies back then showed that when the average daily temperature fell below 65, residences began turning on the heat. To this day, many sources still track degree days using this standard, including the National Oceanic and Atmospheric Administration (NOAA).

Today's residences and commercial/institutional buildings are very different. Not only are walls, roofs and windows insulated much better, but also there are many more sources of internal heat gains (lights and equipment). Extensive use of degree day correlations by thousands of EnergyCAP users since 1982 has shown that a 55 or 60-degree balance point for modern buildings is almost universally more appropriate than 65.

Since residences have fewer sources of internal heat gains per square foot (occupants, lighting and equipment), you might find that 60 or even higher is a better balance point estimate, particularly in older residences that lack tight windows and high levels of insulation. In non-residential buildings, use a higher balance point (56-60+) for buildings that have low internal heat gains, high ventilation rates and poor insulation.

In EnergyCAP, it is possible to change the degree day balance point temperature:

Use Tools > Options > Global, then click the Cost Avoidance tab to access the global settings
The settings will be shown on the Weather Station Manager as Cooling Needed Above or Heating Needed Below.

If the balance point temperature is changed, the charts will be automatically updated the next time they are displayed.

Adjusting and Normalizing Cost and Usage Data for Weather

EnergyCAP has sophisticated weather adjustment and normalization capabilities. See Cost Avoidance.