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6.2.3 Geographic and Climate Data

The following data needs to be specified or derived in some manner. Software developers may use any acceptable method to determine the data. For instance, zip code could be entered and every thing else could be derived from this. Alternatively, state, county and city could be entered and the other variables could be derived from those. If the software allows for the parameters to be individually specified, then data validation should be employed to verify that the inputs are consistent with each other.

Zip Code
Applicability All projects
Definition One of approximately 44,000 postal designations in the United States
Units List
Input Restrictions None
Baseline Rules Not applicable
Latitude
Applicability All projects
Definition The latitude of the project site
Units Degrees (º)
Input Restrictions None
Baseline Rules Not applicable
Longitude
Applicability All projects
Definition The longitude of the project site
Units Degrees (º)
Input Restrictions None
Baseline Rules Not applicable
Elevation
Applicability All projects
Definition The height of the building site above sea level
Units Feet (ft)
Input Restrictions None
Baseline Rules Not applicable
Thermal Zone
Applicability All projects
Definition One of eight thermal zones defined in ASHRAE 90.1-2004 and later
Units List
Input Restrictions None
Baseline Rules Used to determine building envelope and other criteria
Moisture Zone
Applicability All projects
Definition One of three moisture zones defined in ASHRAE 90.1-2004 and later
Units List: Moist (A), Dry (B), or Marine (C)
Input Restrictions None
Baseline Rules Used to determine building envelope and other criteria
Time Zone
Applicability All projects
Definition The time zone measured from GMT
Units List
Input Restrictions Typically derived from other inputs such as zip code or state
Baseline Rules Same time zone as the proposed design
Daylight Savings Time Observed
Applicability All projects
Definition An indication that daylight savings time is observed. The schedules of operation are shifted by an hour twice a year and this affects the time occurance of solar gains, temperature and other factors
Units Boolean (True/False)
Input Restrictions Typically derived from other inputs such as zip code or state
Baseline Rules Same as the proposed design
State
Applicability All projects
Definition The state where the project is located
Units List
Input Restrictions None
Baseline Rules Not applicable
County
Applicability All projects
Definition The county where the project is located
Units List
Input Restrictions None
Baseline Rules Not applicable
City
Applicability All projects
Definition The city where the project is located
Units List
Input Restrictions None
Baseline Rules Not applicable
Weather Data for Simulation
Applicability All projects
Definition The hourly (i.e., 8,760 hour per year) weather data  to be used in performing the building energy simulations. Weather data must include outside dry-bulb temperature, outside wet-bulb temperature, atmospheric pressure, wind speed, wind direction, cloud amount, cloud type (or total horizontal solar and total direct normal solar), clearness number, ground temperature, humidity ratio, density of air, and specific enthalpy.
Units Various
Input Restrictions Weather data should be representative of the long term conditions at the site
Baseline Rules Weather data shall be the same for both the proposed design and baseline building
Ground Reflectance
Applicability All projects
Definition Ground reflectance affects daylighting calculations and solar gain. The reflectance can be specified as a constant for the entire period of the energy simulation or it may be scheduled, which might be appropriate to account for snow cover in the winter.
Units Data structure: schedule, fraction
Input Restrictions Default of 0.30
Baseline Rules Ground reflectance shall be the same for both the proposed design and the baseline building when it is specified to capture snow cover. When specific design features are incorporated to increase or reduce reflectance for the purpose of enhancing daylighting, there can be variation between the proposed design and the standard design, when appropriately documented.