Zone Type

Activity tab in model data under Activity Template header

The zone type can be set at block or zone level on the Activity tab. The options depend on the whether you are working on an ASHRAE 90.1 model or not. If it is not an ASHRAE 90.1 model then the Zone type can be one of:

• 1-Standard - the zone is within the main envelope and is usually (but not necessarily) occupied and heated and/or cooled. This zone type also covers zones within the main building envelope that are unoccupied and not directly heated or cooled such as offices that are temporarily unoccupied may come into this category.
• 2-Semi-exterior unconditioned - the zone is unoccupied and is neither heated nor cooled and lies outside the main building envelope. Examples of unconditioned spaces are roofspaces, sunspaces, crawlspaces, car parks etc.
• 3-Cavity - the zone is a narrow sealed vertical cavity such as the glazed cavity within a double façade or a Trombe wall. This algorithm calculates the convection coefficients for such a cavity based on the ISO 15099 standard.
• 4-Plenum - the zone is a plenum which is unoccupied and has no heating, cooling, or mechanical ventilation (though of course air can flow through it to meet the needs of the zones it serves).

Otherwise if it is an ASHRAE 90.1 model then the following options are available.

• 1-Conditioned - the zone is within the main envelope and is usually (but not necessarily) occupied and heated and/or cooled. This zone type also covers zones within the main building envelope that are unoccupied and not directly heated or cooled such as offices that are temporarily unoccupied may come into this category.
• 2-Unconditioned - the zone is unoccupied and is neither heated nor cooled and lies outside the main building envelope. Examples of unconditioned spaces are roofspaces, sunspaces, crawlspaces, car parks etc. Note: that setting a zone to have 2-Unconditioned zone type does not ensure that it has no heating and cooling. You must ensure that through the HVAC system definition.
  
• 3-Cavity - the zone is a narrow sealed vertical cavity such as the glazed cavity within a double façade or a Trombe wall. This algorithm calculates the convection coefficients for such a cavity based on the ISO 15099 standard.
• 4-Plenum - the zone is a plenum which is unoccupied and has no heating, cooling, or mechanical ventilation (though of course air can flow through it to meet the needs of the zones it serves).
• 5-Semiheated - the zone is heated to a low level only. This option is only available for ASHRAE 90.1 models. In exceptional cases where an ASHRAE 90.1 model has been converted to non-ASHRAE 90.1 model, any zones with the 5-Semiheated zone type are treated is if 1-Standard had been selected.

Zone types are also described in the Partitioning blocks to create zones tutorial

Note: Zones having one of the 2-Semi-exterior unconditioned, 3-Cavity and 4-Plenum zone types do not have their floor area included in the building total floor area in the summary reports.

2-Semi-exterior unconditioned

When the Zone type is set to 2-Semi-exterior unconditioned, the program asks you 'Do you want to load default unconditioned data including Activity, Lighting and HVAC templates?' If you reply 'Yes' then the zone is set as unoccupied by loading <None> Activity, HVAC and Lighting template data.

Also Semi-exposed constructions will be used instead of standard partitions for adjacencies with 'Unconditioned' zones. For example the wall between an occupied office and a car park would use the Semi-exposed construction, whereas the wall between two occupied offices would use Internal partition construction.

Also roofspace insulation is applied in the floor of a Semi-exterior unconditioned space when it is above a Standard space, if 'Floor fitted above floor slab' option is checked.

2-Unconditioned

When the Zone type is set to 2-Unconditioned

3-Cavity

When the Zone type is set to 3-Cavity, the program asks you 'Do you want to load default 'cavity' data including appropriate convection coefficients, calculation options and Activity, HVAC and Construction templates'. If you reply 'Yes' then the following changes are made:

• The zone is set as unoccupied by loading <None> Activity, HVAC and Lighting template data.
• Suspended floors and ceilings are switched off.
• The 5-Cavity Inside convection algorithm is set for Cooling design, Heating design and simulation calculations.
• The 3-Full interior and exterior Solar distribution algorithm is set for Cooling design and simulation calculations.

You can find out more about Trombe wall simulations in the Modelling Issues section.

4-Plenum

When the Zone type is set to 4-Plenum, the program asks you 'Do you want to load default plenum data including appropriate convection coefficients, calculation options and Activity and HVAC templates?'. If you reply 'Yes' then the following changes are made:

• The zone is set as unoccupied by loading <None> Activity, HVAC and Lighting template data.
• Suspended floors and ceilings are switched off.
• The 4-Ceiling diffuser Inside convection algorithm is set for Cooling design, Heating design and simulation calculations.

You can find out more about modelling plenums under HVAC.

Unconditioned zone type (ASHRAE 90.1 only)

In ASHRAE 90.1 models, when the 2-Unconditioned Zone type is selected you must define whether the unconditioned zone has normal levels of airtightness, or it is outside the main envelope. The options are:

• 1-General for unconditioned zones having normal levels of airtightness.
• 2-Ventilated crawlspace/attic etc for zones outside the main envelope such as attics, crawlspaces and car parking which are unsealed and have no provision for airtightness.

Note: Zones having one of the 2-Unconditioned zone types and 2-Ventilated crawlspace/attic etc Unconditioned zone ventilation do not have their floor area included in the building total floor area in the summary reports.