FUTURE DEVELOPMENT IMPACT STUDY ON MICROCLIMATE OF CLEANTECH PARK
Prasanjeet Devi ilamathy S Keerthana Ranjani Shao Yuntao Wang Jiangpeng 1
OBJECTIVE: To develop the 3-D model for existing and future proposal of cleantech business park. To evaluate the prevailing microclimate for the existing and future proposal scenarios using simulation software's like Steve tool, ENVImet, CFD, RayMan and on-site measurements. To assess the thermal outdoor comfort index using Thermal Sensation Prediction Vote (TSV) equation developed by Yang Wei and Physiological Equivalent Temperature (PET) using RayMan to understand the microclimate of the existing and future proposal. To analyse and compare the two scenarios with climatic parameters to identify the key hotspots on site, discussing the influencing factors. To develop and simulate future development with implementation of effective mitigation strategies integrated with the site planning for improvised climatic conditions on the site.
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LITERATURE REVIEW Title
Author
Remarks
Outdoor thermal comfort acceptable Ping Lin et al., 2009 range and campus microclimate in hot-humid region
This study experimented the outdoor thermal comfort at five public spaces in Taiwan which has1644 set of measurement data. The thermal comfort range for Taiwanese outdoor occupants indicates PET 26 - 30 °C PET for “neutral”. It concludes that Sky view factor plays an important role in providing better outdoor thermal comfort. Lesser the factor, more comfortable the outdoor environment.
Urban Heat Island: Causes, Effects Md Nuruzzaman, 2015 and Mitigation Measures - A Review
This paper examines the various mitigation measures for encountering UHI effect, by explaining how these strategies work. It is recommended that vegetation can be the most effective mitigation strategy. Alternatively, high surface albedo materials is also proven to be feasible. 3
LITERATURE REVIEW Title
Author
Remarks
Local climate change and urban heat Hashem Akbari et al., 2015 island mitigation techniques – the state of the art
This paper use of the simple stateof-art technologies to mitigate local climate change. It mainly focuses on the development of reflective materials, cool roofs, cool pavements, green roof and other mitigation measures.
Outdoor Thermal Comfort In Urban Yang Wei, PhD Thesis, 2014 Spaces In Singapore
This study investigates the outdoor thermal for urban spaces in Singapore based on field surveys. The outdoor thermal comfort prediction (TSV-PD) model developed can be used to evaluate the thermal sensation of users under certain outdoor thermal environment in Singapore
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METHODOLOGY • SITE INVESTIGATION- The selection of the site was based on the idea to identify existing low development with proposed master plan of dense development. Step-1 • ON-SITE MEASUREMENTS- Site visit to cleantech park was followed by on-site measurements of climatic parameters like wind velocity, air temperature, RH & mean-radiant temperature for determining the Step-2 outdoor thermal comfort index.
• SITE MODELLING- 3-D massing models for existing and future proposal was done using Google sketch-up for the purpose of simulation. Step-3 • BUILDING SIMULATION- Using steve tool, CFD, Envimet, RayMan for existing case and future proposal of the site. Step-4 • COMPARISON & ANALYSIS OF DATA- The key hotspots for the site is identified by climate analysis using simulations, reasoning with the influencing factors .Also, the thermal outdoor Step-5 comfort index are assessed using TSV & PET. • PROPOSAL OF MITIGATION MEASURE: Based on the analysis of the site, mitigation measures are proposed integrated with the site planning for reduction of UHI and Step-6 enhancing microclimate.
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TOOLS AND TECHNIQUES USED FOR THE STUDY The Screening Tool for Estate Environment Evaluation (STEVE tool)- This tool is used to generate temperature maps for the site to identify the key hotspots. It is also used to implement the mitigation measures on the site integrated with the building and compare the improvement in climate with the existing scenarios. ENVImet- This tool is used to obtain the climatic parameters like wind velocity, temperature and humidity for any time in a year for the existing site. Rayman- This is used to calculate the PET for urban structures based on the parameters like air temperature, humidity, cloud cover, surface albedo etc. CFD - Used to analyse the wind pattern around the existing building
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ON-SITE INSTRUMENTS Globe Thermometer to measure mean radiant temperature Digital meter to measure air temperature and humidity Air velocity transmitter to measure the wind velocity. The measurements were taken from 9:30 am to 5:30pm at 8 different locations, with a time interval of 2 hours.
Globe Thermometer
Digital Meter for air temperature & RH
Site Visit Photos Air Velocity Transmitter
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LIMITATIONS OF STUDY Site measurements if taken for various times of the year, will improve the accuracy of results for measuring the climatic factors of the site. ENVImet and CFD was not done for future master plan because of the heaviness of the file to run the simulations.
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SITE STUDY PROPOSED SITE: CLEANTECH PARK
AREA: 50 HECTARES (120 ACRES) ADJACENT ROADS: Nanyang avenue, Nanyang cres, Pan island expressway
ESTIMATED COMPLETION: 2030
CleanTech Park is an eco-business park in Singapore, the first in the nation. R&D and test-bedding site for early adoption of green technology and solutions. In addition to focusing on hosting environmentally friendly industry, the complex is being developed by JTC Corporation with an eye towards environmentally responsible practices, with �green buildings� and maintenance of natural terrain. The other important draw for the clean tech hub is its location. The CleanTech Park is adjacent to Nanyang Technological University (NTU), which enables knowledge sharing and promoting partnerships between businesses and the academe. 9
CLEANTECH PARK
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CLEANTECH ONE
CLEANTECH TWO
POTTERY THOW KWANG INDUSTRY PTE
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CLEANTECH ONE The six-storey two-towered building with over 37,000 square metres of space houses various local and international organisations to create a diverse hub for clean technology. Surbana International Consultants designed the towers and CleanTech One is listed as a Green Mark Platinum building.
•
• • •
CleanTech One has an east-west facing façade to maximise solar orientation, while abundant greenery reduces heat gain. Solar panels are also installed on the roof and energyefficient lighting is installed throughout the building. one-megawatt fuel cell plant supplying renewable energy, a bio-digester to eliminate food waste a dehumidification chiller to provide a pleasant office atmosphere.
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CLEANTECH TWO Located next to JTC CleanTech One, JTC CleanTech Two @ CleanTech Park offers 22,300 sqm of flexible spaces to meet industry players' demand for offices, workshops and dry/wet laboratories for clean technology (cleantech)related R&D activities.
• • • • • •
46.7% improvement in lighting power budget over code 40 kWp solar panels as a renewable energy source Conservation of selected existing trees Harvested rainwater for irrigation, NEWater for cooling towers and grey water recycling for flushing Individual BTU Meters for all tenant spaces and implementation of green lease IAQ dashboard and low energy fume hoods for all fitted laboratories
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EXISTING SITE WIND SIMULATION ANALYSIS USING ENVIMET AND CFD
Tmax COMPARISON
1 1.95°C
3 3.23°C
2 2.96°C 14:30 Point 1 Point 2 Point 3
Delta T 1.95 2.96 3.23
Delta PET
3.40
Tmin COMPARISON
1 4.17
3 3.82
2 4.05 5:30 Point 1 Point 2 Point 3
Delta T 4.17 4.05 3.82
Delta PET
4.50
Wind COMPARISON
1
3
2
16:30 Point 1 Point 2 Point 3
Delta V 0.25 0.04 0.01
Air Temperature at Point 3
ENVImet
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34.2634.4433.71 33.16 32.46 32.22 30.88 30.3230.21 30.32
35
30
28.31 31.0331.4630.91 30.44 30.35 26.91 26.63 29.60 25.82 29.01 28.55 28.5428.70 25.11 24.33 25 23.2422.85 26.17 22.5121.97 21.6921.4321.18 24.70 20.95 23.70 23.06 22.80 22.23 20
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Ta R=0.8 Point 3
19.0018.68 18.3918.1117.85 17.6117.3817.16
Delta T3
10
5
Ta R=0.4 Point 3
4.24 4.17 4.12 3.86 3.84 3.82 3.80 3.79 3.57 1.78 1.51 1.87
3.23 2.98 2.80 2.62 2.81
0
Air Temperature at Point 3
2.02 1.77 2.14 2.21 2.12 2.31 2.10
RH at Point 3
ENVImet
120
100
101.20 98.4898.4698.4598.4498.4398.4298.4198.41 97.6197.9298.8 95.5596.0196.42 93.5294.3595.01
80
60
93.76 91.11 89.19 87.25 84.85
85.46
79.63 79.47 75.56 71.45 77.93 67.44 76.78 65.76 75.05 64.05 62.60 71.75 61.38 68.55 68.12 65.28 63.76 61.42 56.74 51.58 51.03 48.04 46.43 46.15
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18.0519.5719.1317.44 16.4116.0115.2316.17 16.0616.98 14.71 14.18 11.0811.80
20 4.96 4.11 3.44 2.89 2.42 2.00 0.80 0.49 2.40
7.53
0
RH at Point 3
RH R=0.4 Point 3
RH R=0.8 Point 3 Delta RH
Wind Speed at Point 3
ENVImet
0.9
0.80 0.8
0.79 0.80 0.80 0.79 0.78 0.77 0.78 0.77 0.73
0.73 0.71 0.72 0.72
0.7
0.6 0.50 0.50 0.50 0.49 0.49 0.49 0.48 0.48 0.48 0.48
0.5
0.51 0.5 0.5 0.5 0.51 0.5 0.5 0.49 0.49 0.48 0.48 0.48 0.49 0.49 0.49 0.49 0.49 0.49 0.49 0.49 0.49 0.49 0.49 0.49 0.4 0.29 0.3
0.29 0.29 0.30 0.29 0.29 0.28 0.27 0.28
0.25
Va R=0.4 Point 3
Va R=0.8 Point 3 0.23 0.24 0.23 0.24
Delta V
0.2
0.1 0.01 0.01 0.01 0.00 0.00 0.00 -0.01 -0.01 -0.01 -0.01 0
-0.1
Wind Speed at Point 3
Ta & RH at Point 3
ENVImet
35.00
110.00
30.00
90.00
25.00 70.00 20.00 50.00 15.00
Ta R=0.8 Point 3 RH R=0.8 Point 3
30.00 10.00
10.00
5.00
0.00
-10.00
Ta and RH at Point 3
PET at Point 3
RayMan, ENVImet
60 Thermal Sensation PET range for Singapore
Slightly cool
Neutral
Slightly warm
Warm
Hot
Very hot
20-24
24-30
30-34
34-38
38-42
>42
50 44.1
40
45.2 46
47.3
48.2 48 45
44.6 43.2 43.9 42.6 42.3 42
37.1
39
40.8 36.2 30.6 30 25.6
31.7
26.7 24.5
28.6
20
22.9
25
19.1 18.7 18.3 17.7 17.4 17.2 18.5
21.8 21
PET R=0.8 Point 3 20.1
22.4 20.7
19.7
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PET R=0.4 Point 3
19.6
18.6 18
14.2 13.9 13.6 13.3 13 12.7 13.9 4.9 4.8 4.7 4.4 4.4 4.5 4.6
5.9 5.4
4.3 3.4 3.3 2.9 3.4 4.1
0
PET Comparation at Point 3
3
2.8
2
1.7 2.1 2.2 2.2 2.4 2.1
Delta PET
EXISTING SITE WIND SIMULATION USING CFD INFERENCE: The profile of the building, reduces the wind velocity in the south faรงade, in the future development the jtc is making the building porous to have better wind profile. AVERAGE WIND VELOCITY @ 2M from ground 1.39 m/s @15M from ground 2.21 m/s @30M from ground 3.41 m/s
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Data Source
Jurong West Weather Station Records, from NEA website
TSV USING MEASURED READING
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TSV AND PET USING ENVIMET AND RAYMAN
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28
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EXISTING SITE SIMULATION FOR TEMPERATURE USING STEVE TOOL
Results:
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Tmax: 32.92 Tmin: 24.41 Tavg: 27.52 Tavg-day: 29.83 Tavg-night: 27.06 SVF: .95
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1 2
1 1.
1 2.
2
The temperature at the road junction is the hottest on site with max temp. of 32.92 deg C The second hot spot is also near a road junction with a fairly lower max temp. of 32.69 deg C
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1 2
TSV AND PET USING STEVE TOOL
INFERENCE
EXISTING FULL SITE SIMULATION FOR TEMPERATURE USING STEVE TOOL
Point 1
2
1
Point 2
3
Point 3
Results : Tmax: 33.27 Tmin: 25.30 Tavg: 28.27 Tavg-day: 30.05 Tavg-night: 27.46 SVF: 1.00
FUTURE PROPOSAL SITE SIMULATION FOR TEMPERATURE USING STEVE TOOL
Tmax COMPARISON Point 1 Tmax – 33.6 TSV – 1.7 PET – 35.1 Point 2 Tmax – 33.7 TSV – 1.7 PET – 35.2 Point 3 Tmax – 33.3 TSV – 1.6 PET – 34.9 Point 4 Tmax – 33.7 TSV – 1.8 PET – 35.2 Point 5 Tmax – 33.5 TSV – 1.7 PET – 35.0
- Hotspot
Future Proposal 38
Tavg COMPARISON - Hotspot - Water body
Future Proposal
Existing site Reasons: The major hot spots are identified in roads and less vegetation area
Reasons: Most of the hotspot identified are on, 1. The roads, especially road junction 2. Areas where vegetation is less 3. In-between massive buildings, where there is less wind movement. 4. Due to evaporative cooling the pond may release heat in the night 39
MITIGATION MEASURES
MITIGATION MEASURES
- Hotspot - Prevailing wind direction
FUTURE PROPOSAL BY JTC
- Sun direction
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MITIGATION MEASURES
• The master plan is made porous for the prevailing wind movement to penetrate throughout the site. • The orientation of the buildings are aligned parallel to the wind direction • The buildings that are in the perimeter of the site, which blocks the wind are changed in orientation or been replaced as vertical density, creating a random arrangement throughout the site. • Also it increases the height to width is more • Void ducts are created in the lower portion of the buildings in a regular manner.
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MITIGATION MEASURES • Dense vegetation is planted in hotspot areas, especially shrubs along the road. • Cool or light pavement is proposed • The buildings are treated with green roof and solar panel • The dense buildings are made porous by using courtyards • The building which has main façade facing west or east is treated with green wall or shading
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WIND CONTOUR PROFILE USING AUTODESK FLOW - Northeast wind
BEFORE MITIGATION @ 10m height
BEFORE MITIGATION @ 40m height
AFTER MITIGATION @ 10m height
AFTER MITIGATION @ 40m height 44
WIND CONTOUR PROFILE USING AUTODESK FLOW - Southwest wind
BEFORE MITIGATION @ 10m height
BEFORE MITIGATION @ 40m height
AFTER MITIGATION @ 10m height
AFTER MITIGATION @ 40m height 45
NEW SITE SIMULATION USING STEVE TOOL
HOTSPOT ANALYSIS AFTER MITIGATION
LIMITATIONS: Few of the mitigation measures were not analysed in the new model due to software limitations Example: voids, materials etc.
BEFORE AND AFTER MITIGATION Point 1 Tmax – 33.6 TSV – 1.7 PET – 35.1 Point 2 Tmax – 33.7 TSV – 1.7 PET – 35.2 Point 3 Tmax – 33.3 TSV – 1.6 PET – 34.9 Point 4 Tmax – 33.7 TSV – 1.8 PET – 35.2 Point 5 Tmax – 33.5 TSV – 1.7 PET – 35.0
Point 1 Tmax – 33.3 TSV – 1.6 PET – 34.9 Point 2 Tmax – 33.4 TSV – 1.6 PET – 34.9 Point 3 Tmax – 32.8 TSV – 1.4 PET – 34.5 Point 4 Tmax – 33.5 TSV – 1.7 PET – 35.0 Point 5 Tmax – 33.1 TSV – 1.6 PET – 34.7
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INFERENCE FROM MITIGATION LOCATION OF HOTSPOT
EXISTING TSV
EXISTING PET
FUTURE TSV
FUTURE PET
MEASURE TSV
MEASURE PET
POINT 1
1.7
34.9
1.7
35.1
1.6
34.9
POINT 2
1.6
34.9
1.7
35.2
1.6
34.9
POINT 3
1.6
34.9
1.6
34.9
1.6
34.5
POINT 4
1.8
35.2
1.7
35
POINT 5
1.7
35
1.6
34.7
In all the three cases the TSV is slightly warm to warm and PET is warm. The results after improvement shows slight reduction in PET and TSV but its minimal. The main limitation is that few measures such as material, voidswere not recognized by the software. But the wind velocity contour from Autodesk flow clearly shows improvement in the mitigation site both from Northeast wind and Southwest wind.
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DISCUSSION On-site measurement show that the thermal comfort level is unfavourable at location 7 at 1:30 with TSV 6.91 with 99% feeling dissatisfied with an average temperature of 27.2°C and wind speed as low as 0.07 m/s. On the other hand, ENVImet simulation show that the thermal comfort level is unfavourable at location 3 at 3:30 with TSV of 4.58 with 93% feeling dissatisfies with an average temperature of 35.45°C and wind speed of 0.49 m/s PET for the existing site is 34.9°C and for the future proposal is 34.9°C to 35.2°C.
This shows that the quantification of outdoor thermal comfort should consider both microclimatic factors and thermal adaptation factors.
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