Parametric Windcatcher Model Prototype

Texas A&M University

Department of Architecture

ARCH 653 - Prof. Wei Yan, PhD

Antonio A Vázquez Molinary

Project 1 

Description

Project 1 served as a great opportunity to develop a parametric model prototype for my own research using Revit. As a PhD student, I plan on conducting a parametric analysis of a windcatcher's natural ventilation and daylighting performance within a tropical hot and humid climate. Windcatchers are roof mounted devices that direct the wind to the interior spaces, and they can also act as a light scoop. The windcatcher was integrated in a generic double-loaded corridor building model. Both the windcatcher and the host building were modeled parametrically. 

The model was initially created using a conceptual mass family in which the rooms and windcatcher were modeled as separate volumes. This mass family was then loaded into a project file and where the floor, walls and roofs were generated using the massing tools.  The openings of the windcatcher and the test room that has the windcatcher were then parametrically generated. The parameters of the mass model were associated with global parameters in the project file for convenience. 

The following section describes in more detail how the model was developed using parametric relationships. 

Parameters

Building Parameters

The "Building Parameters" describe the geometric relationships within the overall building that hosts the windcatcher. These are shown in Figure 1 and are briefly described afterwards. Hereafter, the room that hosts the windcatcher is referred to as "Test Room", the other room is referred to as "Windward Room". 

Figure 1 Building Parameters

● Building Width: adjusts the width of the whole building, but not the windcatcher.

● Hallway Width: adjusts width of central Hallway, controls spacing in between two adjacent rooms.

● Test Room Depth: adjusts Test Room depth

● WindwardRoomDepth: adjusts Windward Room depth

● Interior Height: adjusts interior height of all rooms and hallway.

● TestRoomHeight: adjusts height of side of room adjacent to hallway to generate a sloped roof in Test Room. For example, it could be used to create a 14' to 12' sloped roof.

● WWRoomHeight: adjusts height of side of room adjacent to hallway to generate a sloped roof in Windward Room.

Formula = Test Room Height (used to maintain symmetric profiles, could be altered)

● Test Room Slope Angle (reporting parameter): used to calculate roof slope angle

Formula = atan((TestRoomHeight - Interior Height)/Test Room Depth)

● WindwardRoomRoofSlopeAngle(reporting parameter): used to calculate roof slope angle

Formula = atan((WWRoomHeight - Interior Height)/WindwardRoomDepth)

Windcatcher Parameters

The following are the windcatcher parameters defined in the conceptual mass family. They are shown in Figure 2 and briefly described afterwards. In the mass family, the windcatcher was modeled as a rectangular prism.

 

Figure 2 Windcatcher mass parameters

● Depth: controls depth of windcatcher (measured from the exterior surfaces)

● Length: controls length of windcatcher (measured from the exterior surfaces)

● Height: controls height of windcatcher (measured from top surface of hallway mass). In other words, it's measured starting from the "Interior Height" reference line shown in Figure 1. 

Opening Parameters

The following parameters were developed on the "Project" environment in Revit using the "Opening" tool on the wall surfaces of the windcatcher and Test Room. They are shown in Figure 3 and Figure 4 and briefly described afterwards. 

Figure 3 Windcatcher Opening Parameters

 

Figure 4 Windcatcher Interior Opening Parameters

● Opening Height: controls windcatcher exterior opening (inlet) height

● Opening Sill Height: controls windcatcher inlet opening sill height

formula = if(WCHeight - Opening Height - 1'<1' 6", 1' 6", WCHeight - Opening Height - 1')

a conditional if statement was used to ensure that there is always at least a 1'-6" high will under the opening. 

● WC Opening Width: used to calculate internal width of windcatcher and constrain Opening

formula = WC Length - 1' 

(subtracts thickness of windcatcher walls from total Length)

● Interior Opening Sill Height:  controls internal opening sill height

● Interior Opening Height: controls internal opening height

● Interior Opening Height Report: an additional parameter was created to create a formula to ensure there is always a 2' gap between the top of the opening and the ceiling

formula = if(Test Room Height - 0' 6" - Interior Opening Height - Interior Opening Sill Height < 2', Test Room Height - 2' 6" - Interior Opening Sill Height, Interior Opening Height)

Limitations

Through the process of developing the parametric model, some limitations were found, several conflicts were encountered and were unable to be resolved. Future consultation, adjustments or use of Dynamo may be required to resolve the following issues: 

1.  Roof slope angle creates a constraint problem when it reaches 0° and is changed afterwards. 

2. The windcatcher inlet opening and interior openings create constraint problems when changing the mass and making walls update to the mass model. This was not resolved in the submitted model. (refer to video in submission for more details). The openings behave correctly otherwise.

Images and Video