Step 1 - Generative Design Framework
Design variables:
- Structural Design
- Structural material
- Structural member size
- Structural grid
- Structural system
- Architectural Design
- Building envelope
- Orientation
- Location
- Facade material
- Sustainable Design
- HVAC system
- Air flow
- Carbon footprint
- Energy usage
To evaluate the essential tradeoffs resulting from above design variable choices, each decision may have different design evaluators:
- Structural Design
- Structural material weight/size vs. Building response (displacement/deformation)
- Structural grid/system vs. Total material usage
- Architectural Design
- Building envelope/orientation/location vs. View/capacity/people flow
- Façade material cost vs. Appearance quality
- Sustainable Design
- Space efficiency vs. Energy usage
- Carbon footprint vs. Energy usage
Step 2 - Generative Design Study
- For this assignment, I would like to choose sustainable and architectural design as the main design decisions for my Generative Design Study.
- In Dynamo, I used a parametric tower with panelized facade as the base form to be analyzed (Figure 1).
- For the analysis, the main inputs are number of sides, middle radius, and number of U panels. The script also include other parameter inputs that can modify the building form but I kept them as constant when conducting the study. In this way, I can find the relationship between parameters that I am interested in.
- The main outputs are surface and floor area ratio, panel cut-off areas and HVAC loads.
- Surface and floor area ratio:
- Panel cut-off area:
- HVAC size
- The main trade-off for this study is the surface and floor area ratio and the HVAC size since for a project, it is better to minimize both to have a larger space and lower HVAC cost. However, the HVAC size will increase as the surface and floor area ratio decrease. Moreover, the panel cut-off area is depended on the overall shape of the tower (number of sides, middle radius) and the number of panels in U direction. With the generative study, I can have a better understanding of the relationship between each variable, which can help me choose an optimal design solution.
I chose this evaluator since this ratio represents the space efficiency. With smaller ratio, we can provide larger space to users. The surface area is extracted from solid surface area and the floor area is extracted from the intersected area of each floor plane and the solid.
Panelized surface can offer more variations and appearence quality. However, due to parametric shape of the building, the surafces may not be panelized entirely, which will produce panelization inefficiency. To calculate the cut-off area, I first seperated all the surfaces from the solid, including roof surface, ground surface, and wall surfaces. Then, I used the tools from lunchbox to panelized the wall surfaces in U and V directions. To calculate the cut-off panel area, I used the difference between the total surface area and total panel area. Also, to simplify the study process, I kept the number of V-panels as constant.
Since cooling and heating load is important for high-rise buildings, I chose the HVAC size as a new evaluator. The HVAC size is calculated based on the assumption that one ton of HVAC cooling capacity can cool down 500 square feet of floor area. I used the area of each floor divided by 500 as the estimated number of tons of HVAC needed and take the summation of the result for each floor as the total output.
Step 3 - Generative Design Study Results
- As shown in the scatter plot, the y-axis is panel cut-off area and x-axis is the shape of the building (number of sides of the tower). THe size of each scatter point represents the HVAC size and the color represents the ratio. In this way, it is obvious that deceasing the Surf Area/Flr Area ratio will increase the HVAC size. The cut-off panel area also changes with the shape of the building.
- Since I have three input variables, the study generated various options. To narrow down the choices, I applied the filter option to selecte design solutions that fits the design purpose.
