Download The standard design model will not i nclude natural

5.3.5 Natural Ventilation
Natural ventilation may be modeled for a thermal zone in the proposed design. If zone temperature
setpoints are maintained using only natural ventilation, the heating, cooling and ventilation systems may
be shut off.
If the proposed design results in excessive unmet load hours in cooling for any naturally ventilated zone,
then the user must define and specify a capacity for a Supplementary DX Cooling Unit (Section Error!
Reference source not found.) to serve each zone (with excessive UMLH). If the proposed design results
in excessive unmet load hours in heating for any naturally ventilated zone, the user must define a
Supplementary DX Cooling Unit with gas furnace heating to serve each zone with excessive UMLH in
heating.
The standard design model will nclude natural ventilation when the proposed design includes natural
ventilation.
Natural Ventilation Method
Applicability
All thermal zones with natural ventilation
Definition
The method used to model natural ventilation. The choices will depend on the
capabilities of the energy simulation program.
Units
List: choices depend on the capabilities of the energy simulation program.
Input Restrictions
When the building is conditioned solely by natural ventilation, there are no input
restrictions. When the building has mechanical ventilation and cooling in conjunction
with natural ventilation (operable windows), natural ventilation may only be allowed in
the model if the building has interlocks on operable windows or other means of
automatic controls (automatic window controls).
Standard Design
The standard design is the same as proposed.
Air Flow Rate
Applicability
All projects with natural ventilation that use a method that require the specification of
an air flow rate
Definition
The rate of air flow through the thermal zone when the natural ventilation system is
operating
Units
Air changes per hour or cfm
Input Restrictions
Documentation shall be provided supporting the air flow rate for the proposed design.
The air flow rate shall meet mandatory ventilation requirements of the Standard.
Standard Design
The standard design air flow rate is the same as proposed.
Minimum Indoor Temperature
Applicability
All projects with natural ventilation or mixed mode ventilation with automatic controls
Definition
The minimum indoor temperature below which natural ventilation is disabled
Units
Input Restrictions
Standard Design
Degrees F
Fixed at 71°F for mixed mode ventilation and 70°F for natural ventilation
Fixed at 71°F for mixed mode ventilation and 70°F for natural ventilation
Maximum Indoor Temperature
Applicability
All projects with natural ventilation or mixed mode ventilation with automatic controls
Definition
The maximum indoor temperature below which natural ventilation is disabled
Units
Degrees F
Input Restrictions
Fixed at 74°F for mixed mode ventilation and 76°F for natural ventilation
Standard Design
Fixed at 74°F for mixed mode ventilation and 76°F for natural ventilation
Minimum Outdoor Temperature
Applicability
All projects with natural ventilation or mixed mode ventilation with automatic controls
Definition
The minimum outdoor temperature below which natural ventilation is disabled
Units
Degrees F
Input Restrictions
Fixed at 55°F
Standard Design
Fixed at 55°F
Maximum Outdoor Temperature
Applicability
All projects with natural ventilation or mixed mode ventilation with automatic controls
Definition
The maximum outdoor temperature above which natural ventilation is disabled
Units
Degrees F
Input Restrictions
Fixed at 75°F
Standard Design
Fixed at 75°F