Zone Load Data Tab

Acronym - A short description (up to 20 characters).

Description - Enter a detailed description (up to 50 characters).

Type - Specifies the type of zone

Conditioned - maintains zone air at desired conditions.

Unconditioned - Zone is not conditioned.

Plenum - Zones that act as conduits for return air.

Zone Category - Select the category of the zone from a pre-defined list. This is required as for example, the building type may be an assembly, but may have a zone that serves as an office located in it. The building type selected on the project form will then be an assembly, but the category selected for this zone will be of type 'Office'.

Is enclosed (per ASHRAE 90.1-2010 Section 5.5.4.2.3) - If checked, will classify the zone as enclosed as per the description given in ASHRAE 90.1-2010 5.5.4.2.3

IECC 2012 402.3.1.1 Exception for increased Fenestration Area - If checked, will allow for calculations to be run with an increased allowance for vertical fenestration. To check if such an exception is allowed, refer to the IECC 2012 code.

IECC 2012 402.3.1.2 Exception for increased Skylight Area - If checked, will allow for calculations to be run with an increased allowance for skylights. To check if such an exception is allowed, refer to the IECC 2012 code.

Use Building Load Profile or - Allows to user to apply a pre-existing profile to the zone, or use the overall building profile when attempting to run load calculations.

Dimensions

NOTE:  The area and volume of the zone are automatically calculated by summing the individual values for the spaces under the zone. This occurs any time a change is made to space dimensions or spaces are added or deleted. There is, however, a limitation on the per Zone Area and Volume thus calculated. Maximum Zone area is limited to 100,000 SF and maximum Zone Volume is limited to 1,000,000 CF. However, these can be overcome by defining additional Zones or using the Zone Multiplier for multiple zones that are exactly the same.

Area not included in spaces [SF] - Represents extraneous area that has not been included under spaces. This is added to the total space area under the zone.  If none, set to 0.

Number of Zones - Specifies the number of identical zones in the building to the current one. If two or more zones are identical, use this entry rather that creating additional zones.

Thermostat

The thermostat will control the zone to the particular set-point as specified in the zone set point schedule for heating or cooling. It will be responsible for turning the HVAC system on or off based on zone heating or cooling load requirements. The user should input the type of thermostat (eg. proportional etc.) and the range or the dead band in which the thermostat should control the zone temperature to.

Lighting

Type - Specifies the predominant type of overhead lighting used in the zone.  Note that lighting power and type is specified in the space forms.

ASHRAE 90.1-2010 5.5.4.2.3 Exception C or D - If checked, will allow for a calculation to run with reduced daylight area under skylights. This reduced area is based upon the amount of primary and secondary sidelighted area.

Primary Sidelighted Area - The area in square feet of primary sidelighted area with an effective aperture greater than 0.15 and with general lighting controlled as described in section 9.4.1.4 of ASHRAE 90.1-2010.

Secondary Sidelighted Area - The area in square feet of secondary sidelighted area with an effective aperture greater than 0.30 and with general lighting controlled by continuous daylight dimming.

Source

Specifies internal source type due to sources other than people, lights, or equipment. Note that the source rates rate is specified in the space forms.

 

HOW TO HANDLE A PRE-EXISTING UNCONDITIONED ZONE THAT IS NOT PART OF YOUR DESIGN BUT HAS YOUR  ENVELOPE NEXT TO IT

In some instances, you may have to account for a zone that pre-exists and is not part of your design.  Since the calculation requires a physical zone whenever an adjacent envelope is specified next to it, the following procedure suggests how to accomplish it with minimal input and effort.

Steps to account for an Zone that pre-exists.

1) Add a Zone. You may choose to label it as 'PRE-EXIST'.

2) Set the Zone to 'Unconditioned'.

3) Add a Space under this new Zone.

4) Set Space category to 'Unlisted'.

5) Set the width and height of the space equal to the width and height, respectively, of your adjacent wall.

6) Set the depth of the space to a minimum value, say 1 ft.

7) Set No. of Task locations to zero.

8) Add a lighting to the space. Use minimum Watts (equal to what is indicated by the Budget, or say 5 Watts).

9) Set Control Type to 'Security Lighting'.

10) Set No. of Controls to Zero.

11) You can now set your adjacent wall next to this new 'PRE-EXIST' zone.

12) If you are running Method A, you will have to assign the 'PRE-EXIST' zone to some system in the project. As long the 'PRE-EXIST' zone is set to 'Unconditioned', there will be no energy impact.

 

Zone Summary

Assigned Supply Air - Total quantity of supply air assigned to the zone from the system.

Outside Air - The total outside air supplied to the zone. This will be calculated either based on ASHRAE 62.1 if defaulted, or can be supplied by the user for non-code (LEED, ASHRAE Appendix G) simulation runs.

 

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