On the Building menu, click Zones or double-click on the Zones sidebar. You can also use the keyboard shortcut Ctrl+T.
Use the Zones dialog to create a list of zones that you can then apply to the spaces of the building. When you apply a zone to a space, the assumption you are making is that the enclosed volume of air is homogenous. In other words, the model will assume that within the zone, the air can mix freely and this will result in an average zone temperature.
When you apply a zone you should be confident that there won't be any appreciable localized variations in temperature at different hours, otherwise you should divide the floor area into different zones (for example, divide the floor plate along the perimeter on each orientation, and then have one remaining zone in the centre of the room).
You can group two or more rooms which you know will be subject to the same thermal effects into a single zone. You would do this by applying the same zone to each of the rooms. The model will then behave as if the group of rooms were a single volume of air.
In the case of an atrium, the reality of the situation is that the entire volume of air is not going to be homogenous. It will be arranged in layers with warmer, less dense, air at the top of the "stack". This is known as air stratification, or the stack effect. To model this behaviour you would need to divide the atrium vertically into separate air masses and then apply a different zone to each mass of air.
When you develop a model for the building regulations in the United Kingdom, you will be expected to make certain abstractions or simplifications to satisfy a prescribed set of rules. The NCM modelling guide requires that you model the atrium as a single thermal block, so you will have to apply the same zone to the bottom of the atrium, middle, and the top. This doesn't mean that your results will be "wrong", as a model will always be based on one assumption or another, it means that the results will be derived from a model that assumes the volume of air in the atrium is homogenous. And this assumption will play its part, along with other assumptions, in determining the accuracy in the results.
You can apply a zone in a 2D or 3D view but not when you are in analysis mode. A zone will always belong to a zone set, which can contain one or more zones. So you might create a set specifically for zones that are external, or zones that will be unoccupied and unconditioned. In other words you can think of a zone set as being a family of similar zones. For spaces that are external (such as the space in between an external shade and the window or glazed facade), you should tick the External box in order to set the convection coefficient in the TBD accordingly.
| Colour | This is the fill colour that is used in 2D views and also 3D
views that are coloured "by zone" (including floors
and analysis modes).
To change the zone colour you will need to specify how you want to colour the zone (choose from default, plain, random, or variation), and then click on "Set Colour". |
| Name | Enter the name of the zone. On the View menu, point to "2D
Zones", and then select how the zone will be displayed on
a 2D view.
Choose from: "No display", "Name", and "Fill". Selecting "Fill" will display the zone colour, whilst "Name" will display the zone name. You can display both the zone name and fill colour, together. |
| External | Insert a tick in the "External" box to specify the
zone as being open to the outside environment.
External zones are applied mainly to spaces in-between an external shade and the facade of the building. Wherever an external zone is used in the building model, the Building Simulator will set the convection coefficient to "External". |
| Used (checkbox) | When a zone is applied to a room or space, a tick will be visible
inside this box so you will be able to quickly determine whether
a zone has been used in the model.
A grey square instead of a tick will be shown for zone sets which contain a mix of used and unused zones. |
| New Zone Set | This option will create a new zone set, where the number of zones will be determined by the number entered in the "Number" box. This number is "20" by default. |
| Number (text box) | Enter the number of zones to add to a new or existing zone set. |
| Add Multiple Zones | Add zones to the selected zone set, according to the number entered into the Number text box; this number is "20" by default. |
| Colour (drop-down menu) | Click on the zone set and choose from "default",
"plain", "random", or "variation".
Now click "Set Colour". To set all zones to a single
colour, choose "plain" and then select a colour by clicking
on the box under the drop-down list.
To use a random colour for each zone in the set, choose "random". Alternatively, choose a "base" colour on which to base the colouring and then select "variation" in order to set different shades of the base colour to all of the zones in the selected set. |
| Set Colour | After selecting how to colour the zones, click "Set Colour". |
| Add New | Add a new zone to the selected zone set. |
| Delete | Delete the selected zone or zone set. |
| Purge Unused | Delete zones which have not been applied to any space or room
in the geometry.
The zone names will be deleted from the file. |