3.2.3 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. Standard 90.1 Appendix B maps U.S. states and counties to the climate zones. Standard 90.1 Appendix D maps U.S. states and cities to additional climate information, including design temperatures.

 

Zip Code

Applicability

All projects

Definition

One of approximately 44,000 postal designations in the United States

Units

List or text

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

Same as proposed design

 

Longitude

Applicability

All projects

Definition

The longitude of the project site

Units

Degrees (º)

Input Restrictions

None

Baseline Rules

Same as proposed design

 

Elevation

Applicability

All projects

Definition

The height of the building site above sea level

Units

Feet (ft)

Input Restrictions

None

Baseline Rules

Same as the proposed design

 

DOE Thermal Zone

Applicability

All projects

Definition

One of 9 thermal zones defined in ASHRAE 90.1-2004 and later. These are numbered zero (0) through 8. Used to determine building envelope and other criteria.

Units

List

Input Restrictions

None

Baseline Rules

Same as proposed design

 

DOE 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

Same as the proposed design

 

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 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

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

 

Design Day Data

Applicability

All projects

Definition

A data structure indicating design day information used for the sizing of the proposed system. Note that this information may not necessarily match the information used in the annual compliance simulation.

Units

Data Structure: contains the following: Cooling Design DB (1%), Cooling Design Wet-Bulb (1%), Heating Design Temperature (99.6%) 

Input Restrictions

Must match climate data in Standard 90.1, Normative Appendix D.

Baseline Rules

Not applicable

 

Weather File

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

Data structure

Input Restrictions

The weather file selected shall be in the same climate zone as the proposed design.  If multiple weather files exist for one climate zone then the weather file closest in distance to the proposed design and in the same climate zone shall be used. 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.