applications / heat / study 08
Draft for review
Urban heat island effects
Cities run hotter than the countryside around them, and the gap widens at night. We quantify that difference for a district and show what an intervention actually recovers.
- Element
- Heat
- Scale
- District to neighbourhood
- Method
- CFD with radiation and surface energy balance
- Output
- Before and after temperature maps
The question
How much heat is the district holding?
Dense construction absorbs solar radiation during the day and releases it slowly after sunset. Add reduced airflow between buildings and the loss of evaporative cooling where vegetation and water have been replaced by asphalt, and a district can stay several degrees warmer than its surroundings through the night.
That difference is a health issue during heatwaves and an energy issue year round. Quantifying it is the first step to arguing for what should change.
What we simulate
The energy balance of real geometry
We model the district from three-dimensional building geometry and surface data, resolving the airflow between the buildings together with the radiation exchange and the thermal behaviour of each surface: what it absorbs, what it stores and what it releases.
The same model is then run for the proposed situation. Because the two runs differ only in the intervention, the comparison isolates its effect rather than the weather.
What it supports
Evidence for planning decisions
Municipalities and planners use these studies to compare mitigation options against each other: added vegetation, cooler surface materials, water features, or a change in massing that opens a ventilation path through the district.
The result is a map rather than a single figure, which shows not only how much cooling an intervention delivers but where it lands and who benefits from it.
Other studies
Heat