With the appropriate unit group(s) set up and valid properties set (see previous section for details), the unit groups are ready to be assigned to room(s) in your model. The Monodraught HTM® navigator will attempt to guide you through the process of setting up rooms for HTM usage.
Assignment Guidance
In order to accurately simulate HTM performance, any room you want to assign to an HTM unit group must meet the following pre-requisites:
- The room must have one HTM Integrated Louvre for each HTM unit in a room. For example, if an HTM unit group defines the Number Of Units property as 2, the room must have two HTM Integrated Louvres. All HTM louvres are modelled using external doors.
- Each HTM F integrated louvre should have a minimum size of 0.45m2 – the typical dimensions of a standard louvre are 900mm in width and 500mm in height.
- Each HTM FS integrated louvre should have a minimum size of 0.27m2 – the typical dimensions of a standard louvre are 900mm in width and 300mm in height.
It is the user’s responsibility to model the louvres at an appropriate size and position to reflect real-world conditions.
If the Automatically identify HTM® openings on room assignment setting (see previous section for details) is active for the unit group and a room is assigned to that group, any wall-based external door in the room that is assigned a MacroFlo opening type using a Degree of Opening profile other than off continuously will be considered as being available to be used as an HTM integrated louvre. Note that only the required number of suitable external doors (i.e. the # of Units value from the unit group properties) will be automatically used – any additional doors will be left as-is. In addition to handling external doors, all wall-based external windows that are assigned a MacroFlo opening type using a Degree of Opening profile other than off continuously will be automatically used as HTM Natural Vent. Windows.
You will generally set up your model in the normal way beforehand, ensuring that you have defined suitably sized (see the sizing guidance above) and positioned external doors and windows, and with sensible MacroFlo assignments applied. If you need to add on new doors or windows to rooms you are planning on using with HTM, you can use the standard Add Door (
) and Add Window (
) features in ModelIT – simply set a suitable width, height and base height and add the openings.
HTM Assignment
You designate a room to be served with HTM by assigning it to the appropriate unit group in the Monodraught HTM® navigator – this can be done by any of the standard methods (e.g. using the button above the room browser, or by using the Room Groups tab within Tabular Space Data in ModelIT).
Once a room is assigned to an active unit group (i.e. a group other than No HTM Assigned), the room will display a Monodraught logo in the viewport (as well as highlighting which of the openings are attached to the HTM within that room) whenever the Monodraught HTM® grouping scheme is active in the room browser. The logo will also display a small circle overlay at the bottom-right, indicating the number of HTM units being represented in that room:
If a problem is detected with the room set-up (e.g. there was no valid louvre to attach to the HTM unit), then an exclamation mark overlay will be displayed at the top-right of the Monodraught logo – if you hover over the exclamation mark with the select tool ( ) active, a balloon tip will be displayed to indicate the problem with the room. For example:
To correct this scenario, you must set the appropriate number of external doors to act as HTM Integrated Louvres. You can either:
- Edit the opening types of some of the doors in the room (see Editing HTM Opening Types), or:
- Use the Ensure that all rooms assigned to HTM® systems are valid navigator action. This will go through all assigned rooms that are currently marked with an exclamation mark and attempt to correct them.
Note that the presence of the exclamation mark does not indicate that the model cannot be simulated – it simply indicates a problem with the HTM set-up in that room, which may result in inaccurate HTM simulation results.
What happens when a room is assigned?
The act of assigning a room to an HTM unit group makes a number of modifications to that room’s assigned data, internal gains, air exchanges and MacroFlo opening type, each with the intent of setting up the room for an accurate simulation of HTM.
The following modifications are made to the Space Data for the room:
- The Heating Profile will be set to off continuously.
- The Heating Setpoint will be set to Timed and constant 0.
- The Cooling Profile will be set to off continuously.
- The Cooling Setpoint will be set to Timed and constant 0.
- The System Outside Air Supply Variation Profile will be set to off continuously.
- The Variation Profile for any existing Natural and Auxiliary Ventilation air exchanges in the room will be set to off continuously.
In addition, the MacroFlo assignments for any associated external doors (louvres) and windows will be updated – see Opening Type Updates for details.
What happens when a room is unassigned?
The act of assigning a previously-assigned room to the No HTM Assigned unit group will result in the following modifications being made:
- ALL template-derived values for the room will be set back to From Template.
- The MacroFlo opening types assigned to the window(s) and door(s) attached to the unit will be reset back to their original opening type. If the original opening type is now unavailable, it will be set to the opening type specified by the room’s MacroFlo template.
- The construction for any door(s) attached to the unit will be reset back to their original construction. If the original construction is now unavailable, it will be set to the construction specified by the room’s construction template.
- Any automatically created profiles and MacroFlo opening types that are not in use will be removed from the model.
At this point, the room will no longer display the Monodraught logo and any associated openings will not appear highlighted.
