Introducing Kool Air!
A tool to help architects/engineers design structures to optimise natural ventilation.
Intended users
The intended users of this tool would be architects, designers, and civil engineers working on large projects. The tool is limited to towers and tall structures over 200-ft tall. It will give the opportunity to modify specific outputs to optimise natural cooling in the building while minimising cost.
Need you’re trying to provide a solution or support for
With this design assistant, A/E/C professionals would be able to optimise their building design for natural ventilation, and consequently, reduce energy consumption and improve thermal comfort. The tool would compare different metrics against each other, especially building costs. This would allow the building owner to estimate a decision’s impacts on the overall building cost (but not limited to!), and therefore, give an estimate of the economic feasibility of the project.
Inputs
The inputs of this study are the following:
Design variables
- Building shape (sections radius, thickness, shape, etc.)
- Building height
- Construction costs inputs ($ panel/SF)
Design constants
- Building location, climate, and time of the day
- Floor-to-floor height
- Construction costs inputs ($ price per SF of floor area)
- Bottom section footprint
Underlying logic of the model you’ll implement
First, we will gather the user inputs as described in the previous part. The user will be prompted a study range (i.e. how many design generations, intervals for design variables, etc.). The design assistant will then treat these inputs to process different design scenarios. The volume of the building will be computed to determine its height to volume ratio. A larger ratio means that the tower is higher than it is thick/wide. This would help improve the potential for natural ventilation by creating a chimney effect; improving the pressure gradient and temperature gradient inside the building. The building shape and height will be used to determine the percentage of daylight received by the building. Each floor’s outer contour will be offset by 6-ft inside. We would then compute the difference between the two areas to obtain the area that receives the most daylight and divide it by the actual floor area to determine the percentage of the floor exposed to daylight. The cumulative solar insulation will be determined from the building shape, location, climate, and time of the day. This value represents how much solar energy the building’s exterior surfaces receive. A higher value means that the building is more likely to heat up during the day. This would drastically improve natural ventilation by creating a temperature gradient inside the building. Finally, the construction cost will be computed using two variables. The building’s square footage cost will grow linearly from $500 per SF at the ground level to $1000 per SF at 750’ above the ground. Then, the panel cost will be determined by multiplying the panel unit price ($/SF) by the panelised surface square-footage area (i.e. exterior surface, without roof). Both metrics will be added up to make up for the total construction cost of the building.
With all of this in mind, the ideal design should look like a tall, skinny tower.
Outputs
The outputs of this study are the following:
- Height to volume ratio
- Percentage of daylight
- Cumulative solar insulation
- Construction cost
A more extensive explanation of each output is detailed in the previous section.