1.1.1 Intro
This Tutorial Section discusses in detail how Walls are modelled, used & some of their properties within Hero, including how they are integrated into the Visual & Data-Grid Views.
1.1.2 Description
All zones are completely bounded by walls along their edges, and when a zone is initially drawn, the walls for that zone are created automatically. If required, the newly created walls will split & connect to nearby walls from other zones automatically. When two walls are connected like this, we call them Adjacent Walls in Hero.
Newly created walls typically are assigned either the Default properties of walls such as the Default Wall Assembly & Default Wall Heights, or if you adjusted a wall away from these properties, the New Wall will use this Previous Value. For example if you change a wall away from the Defaults to a Fibre-cement Wall that is 2450mm high, then the next zone created will have the new walls as Fibre-cement walls at 2450mm height.
Selecting a Wall
You can select a wall either within the Visual View or the Data-Grid. Walls also share the common context-menu actions of Select Parent (which will select the Parent Zone of the Wall) which can also be called by double-clicking the wall.
The Send to Back feature can also be very useful for walls particularly when special floating walls are aligned over the top walls, so that you can select the desired wall. Select the wall on top and choose the Right-Click Context Menu -> Send-To-Back feature and the previously selected wall on top will now be below any other walls. You can now select the wall on top.
Deleting Walls
Walls can be deleted by selecting the wall and pressing delete (show example); or by using the right-click context-menu delete action within the Visual View (show example); or by right-clicking a wall anchor & choosing the Delete Point action (show example).
When a wall is deleted, the walls to the left & right of the deleted wall are connected so that the room remains contiguous. If you are deleting a Wall Anchor, it will be the wall who has this anchor as its right-anchor that will be deleted.
Moving Walls
Walls can be moved in the Visual View by selecting them and then dragging them into their position. You can also drag the corner anchors of a wall to move that wall point and extend or shrink the length. Walls cannot intersect walls of other zones, and in these situations, Hero will block any attempts to move further. You can move a wall or a wall-anchor in a straight-line direction by holding Shift.
Splitting Walls
Walls can be split into new walls by the Split Drawing Mode feature which is detailed in the Split Drawing Mode tutorial. You can also split a wall vertically by the right-click context-menu action Split Wall (Vertically). This will split the walls & add a new wall-anchor at that point.
Splitting a Wall, be it via the Split Drawing Mode or context-menu actions, can be required to model situations such as when you have different construction assemblies side by side, for example if along a wall the assembly type changed from a brick-veneer to a weatherboard section; or if the height or insulation or external colour or any other property of the wall differed from the other.
You may also need to split walls to change the geometry of a zone, such as when you extending a zone or shrinking it. In certain situations, you need to split the wall to insert a wall anchor before you move it into it’s new position to create the desired final geometry. *** DO AN EXAMPLE like “In this example, we see the existing zone, and the new room plans which may have come from an updated version of the plans and which require us to move the walls. We would use a split wall in the indicated position & insert anchors to be able to shift this section of the zone while leaving the remaining portion. Etc etc”
You can also add further walls to a zone, that do not need to lie along the zone edge, through the Special Floating Wall feature, which is discussed in more detail later.
Merging Walls
Two or more continuous walls can be merged into a single wall using the Merge Drawing mode as detailed in the Split & Merge Drawing Mode section.
PROPERTIES
Geometry
Wall width is calculated automatically and can be seen in the data-grid Width Column. You cannot currently change the Width within the data-grid and it can only be changed by moving the wall anchors
Wall Heights
Walls have a Total Height, and then the Base Height which represents the Height above the Level height that the wall starts, and a Top Height which represents the Height above the Level height that the wall ends. For a typical wall, the Base Height will be 0, and the Top Height will match the Total Height of the Wall. The Total, Base & Top Height of a wall are all visible under the Height column of the Wall data-grid. Changing the base height will shift the top-height & vice-versa rather than effecting the total height.
Angled Walls
Walls are modelled in Hero at a consistent height due to this being how they are modelled within the Chenath engine. For Angled walls, ie those walls whose height changes across its length, the average height across the wall-length must be entered. For example “XYZ”…
Orientation
The orientation of the wall is shown in the Orientation Column of the Data-Grid and show the orientation of the wall in terms of what direction the external side of the wall is facing.
Thickness
The thickness of the wall is determined by the Assembly & Insulation selected for the wall. This is the thickness that is shown in the Visual View, as well as in the optional Thicknness column of the Wall Data-Grid which is default hidden from view. Due to the limitations of the NatHERS Insulation Materials, walls can sometimes be different to actual construction thickness to model the correct insulation R-value & type. We are working on a solution for this but in the meantime, this difference can either be ignored as its impact on the model will generally be quite slight – only effecting the shade object projections slightly as these projections are based on distance to outside face of wall by typically less than 25mm; or the Insulation Type can be changed for the Construction to a Insulation Material that more closes matches available Products on the market, such as changing from Fibreglass to Rockwool or EPS.
WALL CONSTRUCTION
A wall has a Construction or Assembly which is the construction build-up of that wall, including its external cladding, internal surface & any other materials within the assembly.
Walls also have an optional Insulation Option which is the insulation materials specifically for that wall section that get added in addition to its Assembly materials.
In Hero we separate the function of Assembly & Insulation so that the user has flexibility to change & test various insulation types quickly for each assembly & quickly optimise the passive design aspects of the house; as well as for its use as an important reporting metric.
The Wall Construction Library tutorial provides further detail on Wall Assemblies & Insulation Options, and how assemblies & insulation options can be edited or custom created.
A Wall’s Construction in the Project is shown & can be changed within the Wall Data-Grid’s Construction column. The Currently Selected Wall Assemblies from the Construction Library will be shown and a new type can be selected.
When a wall connects to another adjacent wall such as for internal walls, the assembly usually gets automatically changed to the previous internal wall assembly, which by default is an Plasterboard stud wall. Likewise when a wall disconnects from another adjacent wall it will reset to the previous external wall assembly.
When changing an assembly, if the new assembly contains an Insulation Option similar to the current insulation of the wall, this will be selected. However if there is no similar Insulation Option on the new assembly then the default for that assembly will get applied. For example in this example we are changing from a Brick Veneer wall that has R2.0 insulation to a Single Brick wall which has no Insulation Options in its list…when we change the assembly to Single Brick, we can see the Insulation value gets set to the default No Insulation option for that Single Brick assembly.
The Insulation Options available for that Wall Assembly will be shown in the Insulation column. You can select an existing Insulation Option by using the combo-box drop-down menu or you can type in the desired R-value in the table’s cell and hit enter; or for more complicated options you can create a New Insulation Option within the Wall Builder for that assembly. When typing in a R-value into the insulation column, if there is an existing Insulation Option for that Assembly that matches the entered R-Value it will use that Insulation Option, otherwise a new Fibreglass Insulation Option of the desired R-Value is created, assigned to the wall and added to that Wall Construction’s Insulation Option List.
For Example in this Project, the 4 External Walls are all of a Brick Veneer with Non-Reflective Sarking Type Construction. The Insulation Options for this Assembly within the Construction Library are shown in the drop-down menu, and can be selected. If the insulation type desired was a R2.7 insulation batt, we could model this by typing 2.7 and hitting enter. If we go the Construction Library for this assembly, we see this type is now part of the Insulation Option list for that assembly. Alternatively if the insulation was a complicated combination of insulation materials such as a reflective EPS board insulation, we would need to go into the Construction Library and create a new Insulation Option, change the existing insulation material to the desired R-value & type, and add a new air-gap to the assembly to represent the reflective air-space. Now when we select the desired wall in the Wall Data-Grid we can see that this Insulation Option is available for selection.
EXTERNAL COLOUR
Walls can have their External Colours changed to model the different solar absorptances of different finishes. This is changed within the External Colour column of the data-grid which shows a Colour’s name and its solar absorptance. The first three options are the defaults for Light, Medium & Dark, and then there are variety of custom colours that relate to various other colours such as typical Colorbond colours etc.
WALL ADJACENCY
Energy-modelling is heavily concerned with heat-transfer, and the external & internal conditions on either side of the wall, along with the materials of the wall determine its heat-transfer. Similar to many energy-modelling programs, Hero allows the user to specify different adjacency or externality conditions for a wall. This is primarily viewed & assigned through the Wall Adjacency column of the data-grid.
There are a variety of options that can be assigned to a wall depending on it’s state, however some wall adjacency types are locked and cannot be changed.
The default adjacency is an External adjacency, meaning the outside face of the wall is facing the external environment.
If a wall is adjacent to another wall and has been connected automatically by Hero, the Adjacency will depend on what type of Zone the adjacency is between.
For example for two walls within a Single Home or Dwelling, the Adjacency Type is INTERNAL and cannot be adjusted. In this situation, heat transfer is modelled between the two rooms during simulation.
For two walls that separate two different dwellings, such as in a multi-residential project, the Adjacency Type is NEIGHBOURING and again cannot be adjusted. In this situation, there is no assumed heat-transfer between the two rooms in simulations, and this represents an Adiabatic Adjacency, however the thermal mass of the walls are still accounted for in the simulation.
For walls connecting a normal Zone to a Carpark or Corridor Zone, the Adjacency Type is Carpark or Corridor respectively and again cannot be adjusted to a different option. This is modelled similar to Internal Walls in simulations.
Walls that do not have an Adjacent Wall, can have several adjacency types manually assigned in the Data-Grid’s adjacency column.
These Include Neighbouring, which is used to represent Adiabatic situations where no heat-transfer is to be modelled similar to how walls between two dwellings are modelled. This adjacent type is used such as when a wall is adjacent to a neighbouring conditioned building that is not part of the Energy Simulation.
Another Manual Adjacency Option is a Roofspace or Subfloor adjacencies. When this is selected, the Wall is modelled in the simulation with heat-transfer between the wall’s zone & the roofspace or subfloor adjacent. In many way of these situations, the base height of the wall will likely need to change, for example a bulkhead wall that is adjacent to the roofspace, will need a base height similar to the ceiling height next to the wall and this needs to be considered likewise for walls adjacent to subfloor zones..
Another Manual Adjacency Option is the Ground/Retaining Adjacency Type which models the wall as adjacent to Ground, Soil or a Retaining wall. In this situation, for Chenath Simulations, Hero automatically adds a 5m section of soil material to the external or back side of the wall assembly to simulation the thermal mass & temperature of the ground as per NatHERS Practice. So the user does not need to change the assembly type to add a soil layer in the Wall Construction Library as may have been previous modelling practice. ** EXAMPLE OF NEIGHBOURING BUILDING **
Floating Walls which are described in further detail later in this section, also are the only to allow select the unique “Mass” Adjacency Type which represents a Thermal Mass wall.
SHADING
Walls can have shading objects that can affect the way they are simulated, these include:
Being screened by up to 3 vertical shading objects or Screens in front of the wall. This is detailed further in the Screen Model section.
A single horizontal shading object or Eave over the top of the wall. This is detailed further in the Eave Model section.
A left & right wing-wall which are shading objects projecting from the left & right edges of the wall.
It should be noted that any shading objects connected to a wall likewise shade any windows or doors upon that wall in a similar manner.
Walls can be attached to Screens & Eaves using the Attach Screen and Eave Drawing Mode which is detailed further in this tutorial series. Alternatively you can also attach a screen or eave to a wall by accessing the Right-Click context menu on a wall and selecting Connect to Screen or Eave and then click the desired screen or eave to connect the wall to the screen or eave.
Internal walls and many other types of wall adjacencies such as Neighbour & Roofspace adjacent walls cannot have any shading applied to them.
INTERNAL WALLS
Adjacent Walls such as Internal Walls between Zones, or Neighbouring Walls between Zones of two different dwellings have several unique features in Hero.
When selecting an Internal Wall in the Data-Grid, if you have the Zone Group-By header selected, the Data-Grid will show both sections of that wall selected under each respective walls…these walls are the linked sections of each-other within each room and basically represent the same object. Editing one of them within the data-grid automatically updates the other as they are linked together into a single unit.
While external walls have the External Side of the Construction facing outwards, Adjacent Walls are Directional, in that the External & Internal Sides of the Construction (as shown in the Wall Construction Library) can be changed within the assembly.
For the default internal plaster stud-wall, which is a symmetrical assembly with plasterboard on each side & an air-gap or insulation in the stud cavity, the direction of the wall is unimportant. However if the adjacent wall assembly is non-symmetrical, you can ensure the correct direction of the assembly by the Direction arrow on the wall in the Visual View. The arrow points towards the “External” side of the Assembly as per the Wall Construction Library. If the direction needs to be changed, you can flip or reverse the assembly by clicking the Direction Arrow within the Visual View. Modelling the correct direction of a wall is particularly important where the wall has a heavy thermal-mass material with insulation on one side such that the thermal-mass material can have reasonable simulation effects.
FLOATING WALLS
There are modelling situations where we need additional walls to the walls that bound the edges of a zone. In Hero we call these Special or Floating Walls Walls, in that they are not tied to the Edge of the Zone. Floating Walls can generally have the same attributes as normal walls, they can have windows on them, and be attached to screens, eaves & wing-walls etc.
To Draw A Floating Wall use the Draw Special Wall Drawing Mode which is detailed in the Drawing Mode tutorial section.
Special Floating walls can be used to model situations such as:
Horizontally split walls, such as a wall that changes assembly, insulation or external colour half-way up the wall or similar. In this situation we would create a new floating wall over the top of the wall below, and set the Base Height of the Lower to 0, the Height of the Lower Wall to the height where the transition occurs above the level reference, and then set the height of the upper wall section. ** Show Example with Drawings & Hero **. Splitting a wall like we have just done is also required in the situation where there is a local shading object a portion of the way up a wall and an unshaded section above. An eave that has a negative vertical offset would be incorrect in this example as it means all the wall above that vertical offset will be shaded in the model, whereas in this situation there is a portion that is unshaded that we may want to model. A split wall with an eave attached to the local portion would be the appropriate solution for this situation. ** SHOW EXAMPLE WITH DRAWINGS & HERO **
We can also use Special Floating Walls to model Clerestory walls that lie above the ceiling of the zone. In this situation the base height of the wall may need to be increased to the ceiling height where the clerestory begins. Eaves & windows can be added to this Floating Clerestory as per normal walls. ** Show Example with Drawings & Hero **
Walls that are adjacent to Special Zones such as Roofspace Zones or Subfloor Zones. Floating walls can be used in this instance with the adjacency type changed to Roofspace or Subfloor type in the Data-Grid Wall Adjacency column. ** Show Example with Drawings & Hero **
Walls or wall-like objects completely within the zone that provide sufficient thermal mass that you would like to model their effects. We call these Internal Thermal Mass walls within Hero, and they can be modelled using a Floating Special Wall & the Thermal Mass wall adjacency option in the data-grid. For example in this project, the Living room has a small spine wall of solid brick that due to its high thermal mass, could effect the simulation results. To model this wall we create a Floating Wall, change its assembly to the correct Single Brick assembly type and assign the Adjacency as MASS wall. ** Show Example with Drawings & Hero **
WALLS FOR SPECIAL ZONES – ROOFSPACES & SUBFLOORS
Special Zones such as Roofspace Zones & Subfloor Zones also can have their own walls that are automatically generated by Hero and appear in the Data-Grid. This is discussed in further detail in the Special Zone section of this tutorial series.
NULL WALLS - WALLS WITH NO ADJACENCY
The Chenath thermodynamic calculation engine that underpins Hero is based on 2D heat-transfers through surfaces. Therefore there are situations where Hero cannot properly model the true thermodynamic situation of walls where there are 3D heat transfer interactions.
The most common example of this situation is walls that are facing adjacent to the cavity of a stud-wall such as created between two internal walls. In this situation the heat transfer into the side of the stud cavity cannot be accounted for. Hero will attempt to auto-detect these situations & if detected, will remove the wall segment in this location. However there are some occasions where these walls are not properly auto-detected, and you may see a "real" wall in the model adjacent to one of these conditions. In this case, Hero recommend setting these walls as having Neighbouring adjacency so that there is no heat transfer modelled on that segment.