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 and 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 cavity such as the glazed cavity within a double façade or a Trombe wall. This algorithm correctly calculates the convection coefficients for a narrow sealed vertical 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 will 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 Basic Drawing Tools 6 Tutorial

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.

3-Cavity

When the Zone type is set to 3-Cavity, the program asks you 'Do you want to load default 'Glazed 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 ventilation

In ASHRAE 90.1 models, when the 2-Unconditioned Zone type is selected you must define whether the unconditioned zone is ventilated or unventilated. Options are:

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