Evaporative Cooling System by using Water Mist
Tokyo University of Science
YOON, Gyuyoung
Issue of Urban Hot Climate
Issue of Urban Hot Climate
Heat release Heat release from Build. from Build.
Air pollution Air pollution H ld h t H ld h t Build. Cut down wind
Build. Cut down wind
Hold on heat Hold on heat
Heat release Heat release from Industrial from Industrial Canyon trap
Canyon trap the solar radiation the solar radiation And hold up heat
And hold up heat AbsorptionAbsorption Solar radiation Solar radiation
Energy use Energy use
Energy use Energy use
Heat exhaust from cars Heat exhaust from cars Accumulate heat
Accumulate heat into Road & Build. into Road & Build. Cove r build. Cove r build. by gre e n by gre e n
Cooling by Cooling by Ba re d ground a nd t re e Ba re d ground a nd t re e
Wa t e r pa rk Wa t e r pa rk a nd so on a nd so on Re fle c t Re fle c t Sola r ra dia t ion Sola r ra dia t ion
What is water mist system ?
What is water mist system ?
Out line of Syst e m
Vapor air 33℃
Control Equipment Optional
Water Mist Obtain Evaporative cooling
Be ne fit s
◦ M ode ra t e hot urba n clim a t e
◦ Provide w a t e r t o urba n a re a
31℃ City Water
Water Pump
Valve Sensor
(Optional) Dry Bulb Air Humidity Air Velocity Solar radiation
Installation cases for Water Mist System
Field Surveys for Water Mist System
Aichi Expo 2005 Site
Economics Dept. in Nagoya Univ.
T Build. In Nagoya
Simulation for Water Mist
Valid Simulation results
Define control strategy
Future Work
Promote Practical use in Residence
In the future…
名古屋大学経済学部 Produced by Nago-Mist Co. Ltd. 相模鉄道 二俣川駅 Produced by Nago-Mist Co. Ltd.
愛知県 名古屋 立大学病院 Produced by Nago-Mist Co. Ltd. 千葉県 たい う保育園 Produced by Nago-Mist Co. Ltd.
表参道 原宿かすう工 Produced by Nago-Mist Co. Ltd.
噴霧場
集合住宅ランダ 噴霧場
2階建 住宅庭部分 ッ用として 利用
噴霧場
戸建住 宅ランダ
家庭用 庭 ライ 導入例 導
Produced by Nago-Mist Co. Ltd.
Installation cases for Water Mist System
Field Surveys for Water Mist System
Aichi Expo 2005 Site
Economics Dept. in Nagoya Univ.
T Build. In Nagoya
Simulation for Water Mist
Valid Simulation results
Define control strategy
Future Work
Promote Practical use in Residence
In the future…
>12 of nozzles were installed at each pole of sun roofs.
>Spray water volume is 50 lit/min per a nozzle.
>Nozzles are 3.5m height from FL.
>Spray was conducted by scheduler and control scheme with outdoor conditions.
ノル12個 (30cm間隔)
日除けン
3m ン幅5m
ン間隔
6.6m Installation of Mist Nozzles
Water Mist in Aichi Expo 2005
Water Mist in Aichi Expo 2005
Evaluation for cooling Effect
Evaluation for cooling Effect
ノル12個 (30cm間隔) 日 除けン
ウッッキ
測定場1-1：ン内 温 度，湿度，風速
測定場1-2：ン外 温度，湿度,日射量，降雨有無 ン高さ 3m ン幅5m
歩道幅21m
ック高さ 30cm ンサック間距離
20m ン間隔 6.6m
Inside sun roof Outside sun roof
時間数 ン内外温度差℃ 風速
風速
温度差
温度 ， 日射量
噴霧中
Differential of Temp. Inside and outside
Wind velocity
T he m a x im um c ool dow n e ffe c t w a s a bout 4 K , a nd c ool dow n of a ir t e m pe ra t ure is ove r 1 K w he n t he w ind spe e d is low e r t ha n 2 .0 m /s.
Economics Dept. in Nagoya Univ.
Economics Dept. in Nagoya Univ.
Nozzles : 88 EA 40 ml/min S.M.D. : 24.5 µm Height of nozzle : 2.4 m Spray angle : 50 degree Water Pump : 750 W Measurement Items Dry Bulb, Air Humidity, Air velocity, Air flow direction Globe Temp., Ground surface Temp.
駐輪場 N
連絡通路部
幅 ×長さ
屋外測定点
通路部測定点
風向風速計測点
詳細温度分計測地点
棟
緑地 棟
棟
約
約 風速 風速
Globe Temp., Ground surface Temp.
Economics Dept. in Nagoya Univ.
Economics Dept. in Nagoya Univ.
Fluctuation of Air Temperature and Humidity during Water Mist
Fluctuation of Air Temperature and Humidity during Water Mist
Spraying
Spraying
空気温度℃
屋根下 屋外
相対湿度%
屋外
屋根下
Economics Dept. in Nagoya Univ.
Economics Dept. in Nagoya Univ.
Change of Air Temperature and Humidity due to Evaporative Cooling
Change of Air Temperature and Humidity due to Evaporative Cooling
Effect
Effect
温℃
噴霧停
噴霧実施
線形 噴霧停
線形 噴霧実施
度%
Air Te m p. Air H um idit y
Air Te m p. Air H um idit y
屋根外気温 ℃
通路部気温
屋根外湿度 %
通路部湿度
噴霧停
噴霧実施
線形 噴霧停
線形 噴霧実施
Fa ll dow n
Fa ll dow n
3 de gre e C.
3 de gre e C. Ra ise up Ra ise up
2 0
2 0 --3 0 % 3 0 % rh rh
T Build. In Nagoya
T Build. In Nagoya
北内 北下
南 内
南 下 南外
エン 北外
ノル位置
外 下 内
Number of Nozzles : 36
Height of Nozzles : 2.9 m
Water volume : 50 ml /min
Water Pump Output: 750 W
Outline of
Field Measurement
T Build. In Nagoya
T Build. In Nagoya
Movie for water mist spraying
Movie for water mist spraying
T Build. In Nagoya
T Build. In Nagoya
Evaluation for Cooling Effect
Evaluation for Cooling Effect
℃ ℃
%
◇ Thermal environment for evaluation
% %
℃
℃
℃
≧
≧
◇ Change of comfortable Index
Installation cases for Water Mist System
Field Surveys for Water Mist System
Aichi Expo 2005 Site
Economics Dept. in Nagoya Univ.
T Build. In Nagoya
Simulation for Water Mist
Valid Simulation results
Define control strategy
Future Work
Promote Practical use in Residence
In the future…
2.4m 0.4m 1.8m
0.2m 0.3m
0.4m 0.3m
A B C D E
1 2 3 4 5 6 7 0.2m 0.3m
0.3m
Valid Simulation Results
Valid Simulation Results
Field Measurement and Results
Field Measurement and Results
0.8m 2.6m 0.8m 0.3m
Field
Measurement
Results
Just before start to spray
After 10 Sec. 30 Sec. 60 Sec.
Valid Simulation Results
Valid Simulation Results
CFD Simulation outline
CFD Simulation outline
Z X Y Z X Y
10m
7m
4m
0.4m2.4m
屋根下地面 屋根面
建物壁面
大気圧境界面
大気圧境界面
側面
屋外地面 8ノル
X軸方向か
Z軸負方向へ 45°に噴霧
Out line of Sim ulat ion
CFD code : Fluent Ver 6.3
Number of cells : About ten thousands
Turbulence model : standard k-e model
Spray model : Pressure- swirl atomizer
Water mist Cal. : Discrete phase model
Y Y
0.8m 1.8m 7.4m
Ca lc ulat ion of Dom a in
Mass flow rate 0.83g/s Water temperature 33.4℃ Spray cone angle 50° Injection pressure 6MPa
Spra ying Condit ions
droplets water from pump
liquid sheet
spray cone angle Atomizer Dispersion Angle rotational flow
Pre ssure -sw irl m ode l
Valid Simulation Results
Valid Simulation Results
Compare results of Measurement and Simulation
Compare results of Measurement and Simulation
Field
Measurement
0.8m 2.6m 0.8m
2.4m 0.4m 1.8m
0.3m 0.2m 0.3m
0.4m 0.3m
BA C D
E 1
2 3 4 5 6 7 0.2m 0.3m 0.3m
CFD
Simulation
Results
Just before start to spray
After 10 Sec. 30 Sec. 60 Sec.
Define control strategy
Define control strategy
Example for Control strategy
Example for Control strategy
Start to spray Stop to spray
Air Temp. 31 degree C above 30 degree C under
Humidity
Humidity 60 % 60 % rh rh under under 70 % 70 % rh rh above above
Control Strategy
Air Velocity Mean velocity past tem
min. is lower than
3.0 m/s
3.0 m/s above
Rain fall No rain Rainy
When we apply the water mist system into the space that does not
allow for human face or cloth or floor to get wet, we should make a
control to spray.
But, we have not enough information for proper control strategy, and
we usually take a control strategy above. We should confirm these
empirical control strategy are proper or not.
100% 90% 80% St a nda rd Tok yo
Define control strategy
Define control strategy
C
C ase study ase study
Ca lc ulat ion of Dom a in for c a se st udy
M ist Spra y Z one
(Em piric a l)
乾球温度℃
絶対湿度
70% 60% St a nda rd Tok yo
We a t he r da t a From June t o Se pt e m be r 9 a m -7 pm
Out door a ir c ondit ions for c a se st udy
Start to spray Stop to spray
Air Temp. 31 degree C above 30 degree C under Humidity 60 % rh under 70 % rh above Air Velocity Mean velocity past tem
min. is lower than 3.0 m/s
3.0 m/s above
Rain fall No rain Rainy
Z=1.5m Z=4.0m [ Y=7.5m断面]
+1.0 0.0 -1.0 -2.0 -3.0
温度差[℃] 外気温度：30.0℃
+1.0 0.0 -1.0 -2.0 -3.0
温度差[℃] 外気温度：30.0℃
Y=7.5m Y=8.5m [ Z=1.5m平面]
Y=11.0m
DB, Humid
30 ℃ , 80%RH
Define control strategy
Define control strategy
X=13.0m X=26.0m Z=0.0mX=13.0m X=26.0m Y=4.0m
X=13.0m X=26.0m
Z=1.5m Z=0.0m Z=4.0m [ Y=7.5m断面]
+1.0 0.0 -1.0 -2.0 -3.0
温度差[℃] 外気温度：30.0℃
+1.0 0.0 -1.0 -2.0 -3.0
温度差[℃] 外気温度：30.0℃
X=13.0m X=26.0m
Y=11.0m
Y=4.0m Y=7.5m Y=8.5m [ Z=1.5m平面]
X=13.0m X=26.0m
Z=1.5m Z=0.0m Z=4.0m [ Y=7.5m断面]
+1.0 0.0 -1.0 -2.0 -3.0
温度差[℃] 外気温度：34.0℃
+1.0 0.0 -1.0 -2.0 -3.0
温度差[℃] 外気温度：34.0℃
X=13.0m X=26.0m
Y=11.0m
Y=4.0m Y=7.5m Y=8.5m [ Z=1.5m平面]
30 ℃ , 60%RH
34 ℃ , 60%RH
GL 3 75～3 5 Height [m]
Outdoor air
Temp. 32℃
Define control strategy
Define control strategy
Relationship for air humidity and remain particle
Relationship for air humidity and remain particle
100% 90% 80%
M ist Spra y Z one
Whe n a ir hum idit y is ove r
7 5 % rh, w at e r m ist ex it s
unde r 1 .5 m G.L.
So, 7 0 % rh should be a bounda r y
c ondit ion for c ont rol not t o ge t
w e t
T he n,
%
%
%
%
%
残存粒子量 [] GL 0.25～0.0
GL 0.75～0.5 GL 1.25～1.0 GL 1.75～1.5 GL 2.25～2.0 GL 2.75～2.5 GL 3.25～3.0 GL 3.75 3.5
M a ss fra c t ion For re m a in pa r t icle s (g)
乾球温度℃
絶対湿度
100% 90% 80%
70% 60%
Installation cases for Water Mist System
Field Surveys for Water Mist System
Aichi Expo 2005 Site
Economics Dept. in Nagoya Univ.
T Build. In Nagoya
Simulation for Water Mist
Valid Simulation results
Define control strategy
Future Work
Promote Practical use in Residence
In the future…
Future Work
Future Work
Promote Practical use in Residence
Promote Practical use in Residence
System Components
◦ Nozzles(2EA) : S.M.D. 16µm
◦ Water pump : 100 V / 75 W
84 ml/min, 5Mpa
◦ Pipe : Flexible type
Performance of System
◦ Cooling effect : Drop down 2-3 Degree C
Produced by Nago-Mist Co. Ltd.
Water Pump
In the future…..
In the future…..
Photo by 嶋邦夫, 東京新聞
