Step 1 - Generative Design Framework
A very brief description of the design decisions from Step 1 following the Generative Design Framework.
Building Energy Generation - Sustainability
Design variables: building energy usage, onsite renewable energy generation (PV use, space for
PV placement), carbon emissions and cost of grid electricity (baseline situation)
Evaluators: Cost of PV system, PV system electricity generation, carbon emissions from grid
energy use, cost of grid energy use, payback period of solar array
Tradeoffs: Cost of renewable energy upfront, sustainability due to saved emissions
Building Envelope Insulation
Design variables: Wall and roof insulation R-value, window glazing, solar energy on building
(from solar analysis), window to wall ratio
Evaluators: Annual heating and cooling loads, required mechanical system size, envelope
material cost, embodied carbon of insulation materials
Tradeoffs: Higher insulation reduces operational energy and HVAC sizing costs, increases
upfront material cost and embodied carbon
Structural Floor Plan Optimization
Design variables: Material or building choice (steel, concrete), bay size, floor to floor
height, beam/column spacing
Evaluators: Material cost, embodied carbon embodied carbon, usable floor area,
construction time
Tradeoffs: Larger bays increase flexibility/usable space but drive up material weight and
cost
Step 2 - Generative Design Study
The study chosen for this module was to assess the relationship between building roof area, available roof coverage for PV placement (determining number of PV panels), PV panel efficiency, and cost of electricity from grid (which is dependent on peak vs. offpeak hours and building location). Additional inputs that in practice would vary and are included in this study include cost of panel ($/watt), carbon emission of electric grid generation, and solar panel lifetime. These were all set as constants for this study, and all ranges were set to be within practical limits. The outputs included annual solar energy coverage (in comparison to total building load), payback period for PV system, carbon emissions from grid electricity production, and total system costs over lifetime including electricity from grid costs and panel costs.
Step 3 - Generative Design Study Results
From the scatterplot, it can be seen that buildings with lower floor count for the same square footage (meaning greater roof area) as well as greater usable roof percentage (increasing panel number) have higher annual solar energy coverage and lower carbon emissions, which makes sense because this allows for greater solar generation. Despite larger system costs associated with large PV systems (indicated by the blue hued dots) these systems generally have much faster payback periods (x axis) compared to systems reliant on grid energy.
