Thermal Comfort & Visibility Optimization
Üsküdar Square: Outdoor Comfort
Üsküdar, Istanbul
A parametric urban design study that optimizes outdoor thermal comfort at Üsküdar Square without compromising the visibility of the surrounding cultural landmarks. The existing condition was simulated with Rhino, Grasshopper, Ladybug and Galapagos; UTCI-based thermal comfort calculations were performed; and the visibility-comfort balance was optimized with a genetic algorithm. Strategic placement of green infrastructure reduced the heat island effect while preserving sightlines from the metro exits to the waterfront and the historic buildings.
Site Model
- 3D city model
- Metro exits
Visibility Analysis
- 56 view points
- Historic buildings
UTCI Analysis
- Ladybug / EPW
- 15 comfort points
Galapagos
- Tree placement
- 5-stage optimization
Integrated Result
- Comfort & visibility balance
- 45 trees proposed
The Üsküdar Square study area and the historic buildings around it
Two conflicting goals in the design of a square: staying cool and keeping the view. Evolutionary optimization resolved tree placement, thermal comfort and visual openness simultaneously.
Problem
The undesigned metro exits and heavy concrete cover constrain both the aesthetic and functional potential of the square. Pedestrians have no clear line of sight from the metro exits to the waterfront and the historic buildings. The urban heat island effect grows with the lack of green space.
3D Modeling & Parametric
Rhino + Grasshopper
- 3D modeling for complex geometries
- Visual programming with parametric modeling
- Dynamic design variations
- Multiple scenarios
Analysis & Optimization
Ladybug + Galapagos
- Solar radiation, daylight and thermal comfort analysis
- UTCI evaluation with weather data
- Genetic-algorithm-based evolutionary solver
- Optimal solutions against set criteria
Study Area
A transport hub of historic significance on Istanbul's Asian side. Where ferry, metro and bus lines intersect, the square is surrounded by cultural landmarks such as the Mihrimah Sultan Mosque and the Şemsi Pasha Mosque.
Simulation Process
A three-stage process was followed: visibility analysis, thermal comfort calculation and optimization.
- Defining sightlines from the metro exits to the shore and the mosques
- Placing between 43 and 224 trees with controlled parameters
- Using three different tree models
- Computing UTCI with climate data from an EPW file
- Five-stage Galapagos optimization
Selected points, metro exits, proposed public spaces and the planting zone
Optimization Parameters
| Category | Variable | Value |
|---|---|---|
| Resolution | Number of View Angles | 56 |
| Resolution | Thermal Comfort Points | 15 |
| Optimization | Number of Trees | 43 – 224 |
| Optimization | Tree Size Multiplier | 0.5 – 1.5 |
| Optimization | Gathering Area Multiplier | 0.6 – 1.0 |
| Objective | Unobstructed View Vectors | Maximize |
| Objective | Neutral Comfort Percentage | Maximize |
Results
In the five-stage optimization process, visibility and thermal comfort were first optimized separately. In the final stage the two factors were balanced into an integrated solution.
Visibility Only
Steps 1 & 2
- Maximum: 244 units
- Minimum: 74 units
- Range: 170 units
Thermal Comfort Only
Steps 3 & 4
- Maximum: 47,042,226 units
- Minimum: 45,877,169 units
- Range: 1,165,057 units
UTCI scores and the optimization result
Galapagos Solver results
Integrated Optimization
In the fifth step, the visibility and thermal comfort ranges were combined in search of a balanced solution. The highest fitness value came to 8,058 units: a visibility score of 221, 45 trees, and a 0.5 size multiplier.
Galapagos Optimization Results
| Fitness | Gathering Area | Tree Distribution | Size Multiplier | Number of Trees |
|---|---|---|---|---|
| 8058.22 | 21 | 32 | 0 | 2 |
| 8055.61 | 4 | 32 | 0 | 5 |
| 8055.45 | 14 | 32 | 0 | 5 |
| 8054.49 | 22 | 26 | 0 | 0 |
| 8038.52 | 20 | 36 | 10 | 6 |
Parametric design and environmental analysis tools optimized outdoor thermal comfort; the placement of green infrastructure reduced the heat island effect and made the square more livable.
