Variation of rooftop thermal environment with roof typology: a field experiment in Kitakyushu, Japan
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View abstract on PubMed
Summary
This summary is machine-generated.Green roofs offer the best thermal performance, significantly reducing heat stress. Wooden roofs create dangerous heat, while shaded roofs provide moderate improvement for urban rooftop spaces.
Area Of Science
- Environmental Science
- Urban Planning
- Building Science
Background
- Urbanization is reducing open spaces, making rooftop utilization a key strategy.
- Rooftop thermal environments are critical due to global warming and urban heat islands.
- Limited research exists on how different rooftop types affect thermal performance.
Purpose Of The Study
- To investigate the thermal environment variations across different rooftop typologies.
- To assess heat stress levels at various heights for different roof types.
- To provide data supporting effective rooftop space design for thermal comfort.
Main Methods
- A field experiment was conducted on green roofs (GR), wooden roofs (WR), and shaded roofs (SR) in Kitakyushu, Japan.
- Environmental parameters including solar radiation, air temperature, and relative humidity were recorded at multiple heights.
- Diurnal heat stress variations were analyzed for each roof type and height.
Main Results
- Wooden roofs (WR) exhibited the highest near-surface temperatures and dangerous heat stress levels.
- Green roofs (GR) showed the lowest temperatures and heat stress, remaining in caution or safe conditions.
- Shaded roofs (SR) demonstrated significant heat stress reduction, especially at 1-meter height, highlighting the benefit of shading.
Conclusions
- Green roofs (GR) provide superior cooling, effectively reducing air temperature and heat stress at pedestrian levels.
- Shaded roofs (SR) significantly improve thermal comfort by alleviating heat stress, proving the value of shading devices.
- Near-surface heat stress on WR and SR can be substantially higher than at 1-meter, impacting comfort for lower postures.
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