1. Jyh-Dong Lin, Chen-Yu Hsu, Andika Citraningrum, Putri Adhitana National Central University, Taiwan July 2013 1

2. Presentation Outline 2

3. 3 3 Vegetation (can reduce air temp. 0.4-1 °C) STRATEGIES TO MITIGATE THE HEAT ISLAND EFFECT Cool roofing (can reduce air temp. 0.4-0.8 °C) Cool pavements (can reduce air temp. 0.8°C) Rose et al. (2003) : pavements make up 29-45% of the total city’s land coverage, ± half the total UHI contributing surface coverage. Temp. change in Taipei City from 1961-2005: the number of nights >25°C went from an average of 35 to > 100 days/year daytime temperatures >37°C went from 12 days/year The difference between rural-urban temperature is about 1.83°C from 1995-2004 based on temp. records in 8 major cities in Taiwan.

4. Heat island increase air conditioning energy use Analysis of hourly demand indicates that cooler pavements could save an estimated 100 MW of peak power in LA (H. Akbari et al, 2001) Taiwan green building rating system EEWH minimum requirements  pass 2 prerequisites (energy conservation & water conservation) + 2 optional indicators from among the other seven 4

5. URBAN HEAT ISLAND Increased heat storage Reduced evaporation Increased net radiation (low solar reflectance,trap heat, increased air pollution ) Increased energy use Reduced convection → slow winds speeds 5 Surface heat island Canopy heat island Boundary heat island “a 'reverse oasis’ where air and surface temperatures are hotter than in their surrounding”

6. 6 Green Building Green building ↔ environmental protection building “the practice of creating structures and using processes that are environmentally responsible and resource-efficient throughout a building's life-cycle” (definition by US EPA) 1.Biodiversity 2.Greenery 3.Soil water content 4. Energy conservation 5. CO2 emission reduction 6. Waste reduction 7. Indoor environment 8. Water conservation 9. Sewage & garbage improvement Taiwan green building indicators (EEWH)

7. 7 PERMEABLE PAVEMENT POROUS PAVEMENT Asphalt surface Asphalt base Base layer Drainage Penetrate the surface Rainwater GENERAL PAVEMENT Rainwater Difference between porous and permeable pavement

8. Relationship Between Pavement and Air Temperature HEAT-RELATED CHARACTERISTICS AND PROCESSES IN PAVEMENT Pavement surface Pavement base Pavement subbase Subgrade (ground) Heat conduction between layers Solar radiation Reflected radiation Sun Wind Convective heat transfer Thermal radiation (infrared) 8 The difference in average air temperatures among several pavements is significant only at noon time in summer (particularly during the period 12.00-14.00) Lin et al (2007)

9. To discover the effect of permeable pavement on air temperature To discover the effect of the utilization of permeable pavement on building energy consumption (focused only on the air conditioning energy consumption) 9

10. Water Resource Agency Office, Xindian District, New Taipei City K-type thermocouple, CR10X to record weather data (wind speed, wind direction, irradiance, air temperature and relative humidity) CR1000 to record pavement temperature (soil, DGAC, PAC, GB, PI) data were recorded continuously every ten minutes. 10 Data: June 1-24, 2011

11. NCU (civil engineering) K-type thermocouple, CR200 to record weather data (wind speed, wind direction, irradiance, air temperature and relative humidity) MX100 to record pavement and wall temperature (concrete, AC, wall 1.5m, 3.5m, 5.5m, 7.5m, 9.5m, 11.5m, and roof ) continuously every ten minutes. Site Measurement & Equipment 11 Data: June 1-24, 2011

12. Permeable asphalt concrete Permeable interlocking concrete brick + Dense-grade asphalt concrete Grass block Permeable asphalt layer Graded layer Soil Geotextile layer Gravel Soil Geotextile layer Gravel Graded layer Sand Grass block Geotextile layer Soil Geotextile layer Gravel Graded layer Sand Permeable interlocking concrete brick Geotextile layer Pavement Types to be Measured: 12

13. 13 Study case NCU Main Library pavement design around building 80 mx90 m

14. 14 building pavement Combine with vegetation: 20% 40% 60% 80% 100% CFD Simulation 90 80 60 50 25 Define location,building geometry and materials Input surface temperature Input air temperature, wind velocity, irradiance CFD simulation Outdoor air temperature result CFD simulation Indoor air temperature result

15. 15 pavement temperature changed simultaneously with the change of air temperature and irradiance PAC has the highest temperature on day time, in night DGAC become the highest Grass block and PICB have the lower temperature

16. 16 the highest temperature difference between measurement point 1.5 m and 11.5 m above the pavement is 6.2°C Pavement surface is high during midday and decreased towards sunset time. At midnight, pavement, wall, and roof shared almost the same temperature

17. Type of pavement Air temp. (°C) Irra- diance (W/m 2 ) Wind velocity (m/s) Relative humidit y (%) Surface temp. modelSurface temp. (°C) DGAC34.01039.361.35 66.98 y = -48.080 + 2.212 x1 + 2.507 x2 + 0.007 x3 + 0.067 x4 52.2 PAC34.01039.361.35 66.98 y = -43.732 + 3.338 x1 + 2.330 x2 + 0.005 x3 + 0.074 x4 49.9 Grass block 34.01039.361.35 66.98 y = -0.519 + 0.723 x1 + 1.154 x2 + 0.006 x3 - 0.040 x4 43.3 PICB34.01039.361.35 66.98 y = -4.903 + 1.022 x1 + 1.307 x2 + 0.003 x3 - 0.035 x4 42.0 17 Note: y = pavement surface temp., x1 = wind velocity, x2 = air temp., x3 = irradiance, x4 = relative humidity

18. 18 Effect of Pavement Surface Temperature on Air Temperature for Different Building Height Effect of pavement surface temperature on air temperature of 3 storey building Effect pavement surface temperature on air temperature

19. 19 1.Surface temperature difference between 5 types of pavement is high at noon dense grade asphalt concrete/DGAC = 56.75°C permeable asphalt concrete/PAC = 54.96°C concrete = 51.5°C permeable interlocking concrete block/PICB = 43.63°C grass block = 42.45°C At night all share almost the same temperature. 2.Air temperature above the pavement follows the pattern of pavement surface temperature. At noon, air temperature above DGAC is the highest, followed by PAC, concrete, and PICB. Air temperature above grass block is the lowest.

20. 4.Air temperature around a higher building is cooler than around a lower building. Simulation on 3 storey building shows that, the air temperature is 0.36°C higher for DGAC and PAC. For grass block and PICB, the air temperature is 0.39°C higher. 20 3. Simulation on eight-storey building shows that compared to concrete pavement, applying DGAC and PAC as the pavement material increase air temperature above the pavement. Air temperature surrounding 1-3rd floor and 6-8th floor is. Applying grass block may reduce air temperature above the pavement by 0.06°C. Applying PICB reduce air temperature surrounding 1st floor by 0.63°C, while for 2-8th floor is 0.18°C cooler compared air temperature above concrete.

21. 21 【 1 】 Andersen CT, Foster IDL, & Pratt CJ. (1999). The Role of Urban Surfaces (Permeable Pavements) in Regulating Drainage and Evaporation: Development of a Laboratory Simulation Experiment. Hydrological Processes, 13(4), 597–609. 【 2 】 Gartland, Lisa. 2008. Heat Island: Understanding and Mitigating Heat in Urban Areas. UK: Earthscan. 【 3 】 Kubo, K., H. Kido, & M. Ito. Study of Pavement Technologies to Mitigate the Heat Island Effect and Their Effectiveness. Japan: PWRI. Retrieved from http://www.pwri.go.jp/ eng/activity/pdf/reports/kubo.06.08.12.pdf 【 4 】 Lin, Jyh-Dong, Guang-Yan Cheng, & Cheng-Li Cheng. (2003). Study on the Design Guideline and Regulation of Rainwater Conservation and Infiltration Techniques at Building Site, Sub-project II: The Performance and Experimental Analysis of Porous Pavements. Taiwan: Architecture & Building Research Institute, Ministry Of Interior, Research Project Report. 【 5 】 Lin, Tzu-Ping, Yu-Feng Ho, & Yu-Sung Huang. (2007). Seasonal Effect of Pavement on Outdoor Thermal Environments in Subtropical Taiwan. Building and Environment, 42, 4124–4131. 【 6 】 Rose, L.S., H. Akbari, & H. Taha. (2003). Characterizing the Fabric of the Urban Environment: A Case Study of Greater Houston, Texas. Paper LBNL-51448. Berkeley, CA: Lawrence Berkeley National Laboratory. 【 7 】 U.S. EPA. (2008). Reducing Urban Heat Island: Compendium of Strategies. Washington, D.C.: Author.

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