radiant floor cooling and application in large-scale airport … · 2019. 7. 3. · radiant floor...

Radiant Floor Cooling and

Applications in Airport Terminals

Prof. Dr. Xiaohua Liu

Dept. Building Science,

Tsinghua University, P.R.China

Contents

1. Background

2. What’s happening in airport terminals (AT)?

3. How to improve the AC systems?

4. Applications in China

5. Summary

2

1. Background

Rapid development of civil aviation over the world

Top 10 countries or groups of countries in 2017

3

Revenue passenger-kilometer (billions)

[1]. Data from ICAO Annual Report 2017: Air Transport Statistics, https://www.icao.int

1. Background

Rapid development of airports in China

2017: 229 civil airports 2030s: over 400

4Master plan of civil airports in China by 2030

Existing now

Under

constructionPrepare to build

May build

Energy consumption of airport terminal (AT)

China[1]: electricity 177 kWhe/m2·yr, twice

Japan[2]: primary energy 3002 MJ/m2·yr, 1.7 times

Greece[3]: total energy 234 kWht/m2·yr, 1.3 times

5

[1]. Zhao, Master Thesis, Beijing, Tsinghua University, 2015.

[2]. Liu, 2017 summer research into airport terminals in Japan, data from MLIT Japan and airports.

[3]. Balaras, et al., Energy Build. 2003, 35: 1105-1120.

An airport in China[1] An airport in Japan[2]

65%51%

Chiller

Pump

Cooling

towerAHU

FCU

Lighting

Transportation

Shop & restaurant

Else

E - Chiller

E - Else in EC

S - Chiller

S - Heating

E - AHU / FCU

E - Lighting & facility

E - Else in T

1. Background

Energy consumption of HVAC accounts for 40%~70%

of office buildings

Characteristic of large scale buildings

2. What’s happening

——Airport terminals, railway stations, exhibition halls, etc.

◼High interior space (10~20m or even higher)

◼Occupancy zone mostly within 2m

◼Transparent glass curtain wall

6

Characteristic of large scale buildings——Airport terminals, railway stations, exhibition halls, etc.

42℃ 天窗

54℃ 强光灯

35~38℃ 幕墙

50℃ 荧光灯灯管

44℃ TV平板

35℃ 电子屏幕

31℃ 人员服装表面

32℃ 广告灯箱

30℃ 信息牌、指示牌

Opening

on the topVertical

connecting

space

Opening

at the bottom

Mechanical

exhaust air

Mechanical

fresh air

Accent light

Fluorescent light

TV

Dormant window

Wall

Electronic screen

Billboard

Clothing

Information board

Inner heat sources

◼ Solar radiation from envelope

◼Complex heat sources

7Liu XH, … Springer Press, 2014


Current solutions for AT: jet vent.

8


9

1.1m

3.6m

10m

5.0m

1.7m

15m

26.0°C

26.0°C

30.8°C

26.2°C

25.9°C

31.7°C

射流送风: 16°C

1.1m

3.6m

10m

5.0m

15m

19m

8.5m

1.7m4.5m

南墙

吊顶:

28.7°C

29.7°C

29.5°C

30.8°C

30.9 °C

31.2°C

28.5°C

29.4°C

30.5°C

24m28.2°C 28.1°C

24m地板表面:

空气温度:

Nozzle air supply

Roof

Air temp.

Floor surface

envelope

Temp. control under the height (3~5m) of jet vent., realizing

stratified AC system in large spaces

Liu XH, … Springer Press, 2014


Current solutions for AT: jet vent.

Current solutions for AT-summer

10

0

5

10

15

20

25

15 20 25 30 35 40 45

Hei

ght（

m）

Temp.（℃）

C1

C4

Nozzle air

supply zone

AT

0

5

10

15

20

25

30

35

C1 C2 C3 C4 C5

Temp.

(℃)

AT

Temp. in occupancy zone Vertical temp.

Liu XC, Liu XH, … Energy and Buildings, 2019 (submitted)

Temp. could be well controlled within jet vent. height (3~5m)


Current solutions for AT-winter

11

0

5

10

15

20

25

10 15 20 25 30 35 40H

eight （

m）

Temp.（℃）

C1

C4

Nozzle air

supply zone

AT

0

5

10

15

20

25

30

35

C1 C2 C3 C4 C5

Tem

p.(℃

)

AT

Temp. in occupancy zone Vertical direction


Temp. could be hardly controlled in lower space

due to the lower density of hot air supply


Current solutions for AT

12

0

300

600

900

0

30

60

90

0 2 4 6 8 10 12

风机

送风

余压

(Pa)

AT

F

Air flow rate (m3/h)

0

300

600

900

0

30

60

90

0 1 2 3 4 5 6 7

Fan

pre

ssu

re (

Pa)

AH

U输配系数


0

300

600

900

0

30

60

90

0 1 2 3 4 5 6 7 8 9


AT 1 AT 2 AT 3

10

Fan power ATF of air handling unit =

Cooling/heating capacity


Fan pressureTested ATFRated ATF

Tested ATF ≈ 10 or even lower, restricting the energy

performance of the AC system


Current all-air system

◼ Significant energy consumption for air transportation

◼ Accounting for 30%~50%, even higher than that of chiller

36%

31%

8%2%

23%

45%

5%4%4%

42%

Air conditioning box

Chilled water pump

Cooling water pump

Cooling tower

Chiller

Terminal A Terminal B

AHU

Terminal solution for improving thermal environment

and reducing energy consumption is required!

13Liu XC, Liu XH, … Energy and Buildings, 2019 (submitted)

AHUChiller

AHUChiller


3. How to improve

Radiant floor in AT

辐射地板

分布式送风末端

渗风

建筑开口

顶部排风(排出高温高湿空气)Exhaust air

Dry fresh air

Radiant floor

14

16~20ºC, 8g/kg

15~19ºC

Humidity control

according to

occupants

Temperature

control

High temperature

chilled water

Dry air supply

Liu XH, … Springer Press, 2014

Within 2m

Radiant floor acts as the terminal device improving

thermal environ., realizing high T cooling/ low T heating

Radiant floor in AT

15Liu XH, … Springer Press, 2014

Humidity

control

according to

occupants

Temperature

controlRadiant floor

Dry air

supply

Cooling/heating capacity, dynamic

performance, system design method

and etc.

Efficient dehumidification solutions

Key issues System principle

The same terminal device both in winter and summer

Energy saving potential in AT

3. How to improve

Characteristic of radiant cooling◼ Heat transfer process from cooling medium to heat sources

Radiant

surface

Indoor

air

Other

surfaces

Equipment

Occupants

Lighting

Solar

radiation

Convective heat transfer

thermal resistance

Long-wave radiation

Thermal resistance

Short-wave radiation

Chilled

water

Floor

thermal

resistance

Depend on specific

location and form

Related to surface

temperature and

surfaces view factor

Depend on solar

radiation intensity

Depend on

Floor structure

16Zhao K, Liu XH, … Solar Energy, 2014

3. How to improve

Transient response of solar radiation

17

Solar intensity: 100W/m2，60min~120min

20

23

26

29

32

35

0

30

60

90

120

150

0 60 120 180 240 300 360 420 480 540 600

地板表面温度

( C

)

供冷量

(W/m

²)

时间 /min

地板表面供冷量qf

水侧供冷量qw

地板表面温度Tf

20

23

26

29

32

35

0

30

60

90

120

150

0 60 120 180 240 300 360 420 480 540 600

地板表面温度

( C

)

供冷量

(W/m

²)

时间 /min

地板表面供冷量qf

水侧供冷量qw

地板表面温度Tf

Concrete radiant floor

light radiant floor

Heat flux at surface

Hear supply by water

Surface temperature

Heat flux at surface

Hear supply by water

Surface temperature

Co

oli

ng c

apac

ity (

W/m

2)

Co

oli

ng c

apac

ity (

W/m

2)

Tem

per

atu

re (℃

)T

emp

erat

ure

(℃

)

Time (min)

Time (min)

0

20

40

60

80

100

120

短波辐射

长波辐射

对流换热

Air and surfaces——26℃Cooling water——16℃

Surface

28℃

Solar

50W/m2

Solar

100W/m2

𝑞 = 𝑞𝑐𝑜𝑣 + 𝑞𝑙𝑜𝑛𝑔𝑤𝑎𝑣𝑒 + 𝑞𝑠ℎ𝑜𝑟𝑡𝑤𝑎𝑣𝑒

Short-wave

Long-wave

Convective

Zhao K, Liu XH, … Solar Energy, 2014

3. How to improve

Characteristic of radiant cooling How to calculate indoor solar radiation for system design

18

hom= 100%

ogenize accurate

accurate nosolar

V V

V V

−

−Homogenizing spatial solar distribution

Tang HD, Zhang T, Liu XH, … Solar Energy, 2018

3. How to improve

Characteristic of radiant cooling Limited relative difference for heat flux, cooling capacity

19

-8

-6

-4

-2

0

2

4

6

8

0 2 4 6 8 10 12

Rela

tive e

rror

of heat

flux,

ε(%

)

Sunlight center in pipe axis (m)

1

2

3

4

5

6

7

8

Pipe No.

12

345

678

Flow

direction

Inlet

Outlet

Tang HD, Zhang T, Liu XH, … Solar Energy, 2018

Homogenizing spatial solar distribution

• Taking the dynamic solar radiation into account

• Enough accuracy for system design

3. How to improve


Xi’an International Airport- Terminal 3

◼ Cold area in China, with an area of over 280,000 m2

◼ Check-in hall - 27m departure hall- 10m

◼ Radiant floor as cooling/heating terminal

20Zhang T, Liu XH, … Energy and Buildings, 2013

◼ Design supply/return temperature:14℃/19℃

Xi’an Airport- Terminal 3

21

Diffusers for dry air

Radiant floor

coils under the floor

Zhang T, Liu XH, … Energy and Buildings, 2013


Xi’an Airport- Terminal 3

22Zhang T, Liu XH, … Energy and Buildings, 2013


On-site measurements of the applications throughout 2012-2018

Vertical temperature distribution

23

1.1m

2.8m

12m

7.4m

1.7m

17m

西墙东墙

置换送风: 22.5°C

2m28.3°C28.7°C

29.5°C

30.8°C

30.9 °C

31.3°C

29.7°C29.9°C

30.3°C

30.7°C

31.6 °C

32.2°C

吊顶

33m 48m 33m

地板表面:22.5°C, 38.9W/m2 22.6°C, 37.1W/m2 22.1°C, 38.5W/m2

28.3°C

28.0°C

(天窗: 38.0°C )

27.8°C

23.7°C

0.16

0.82

0.02

角系数:

空气: 1.1m

2.8m

12m

7.4m

1.7m

21.6m

17m

23.5°C

27.6°C

30.3°C

29.0°C

24.8°C

31.4°C

31.1°C

空气温度:

入口23.5°C

Air temperature

Roof

WindowEast wallWest wall

View factor

Displacement

ventilation

Floor surface

Air Gate

Operative temperature

Zhao K, Liu XH, … Solar Energy, 2014

A lower stratified cooling effect compared with jet vent.


Comparison between T2 and T3

Radiant floor Radiant floor

All-air All-air

Temperature (℃) Humidity(g/kg)

Hei

ght

(m)

Hei

ght

(m)

Stratified cooling realized owing to the radiant floor system

24

Temp. Humidity

Zhao K, Liu XH, … Renewable & Sustainable Energy Reviews, 2016


25

20

22

24

26

28

30

32

34

09:30

10:30

11:30

12:30

13:30

14:30

15:30

16:30

17:30

时刻

温度

(℃

)

Other surfaces

Floor surface

Air

Temperature

10

15

20

25

30

35

40

45

09:30

10:30

11:30

12:30

13:30

14:30

15:30

16:30

17:30

时刻

供冷量

(W

/m2)

Cooling capacity

Calculation

Reality

Cooling capacity (Cloudy day)

Tem

per

ature

(℃

)

Hea

t fl

ux (

W/m

2)

time time

Zhang T, Liu XH, … Energy and Buildings, 2013


Solar radiation processing

ABC

D

2.3m

West

wall

0

40

80

120

160

200

Co

oli

ng

ca

pa

city

(W

/m2)

Time

Point A Point B

Point C Point D (under chair)

◼ YES：120~150 W/m2

◼ NO ：30~40 W/m2

◼ Discontinuity of solar spotInfluence of solar radiation?



Winter performance


Uniform vertical temp. distribution in winter, improving

indoor thermal environment


Comparison between T2 and T3

◼ Significant energy saving for air transportation

0

4

8

12

16

20

1 2 3 4 5 6 7 8 9 10 11 12

月耗电量

(kW

h/m

2)

月份

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

1 3 5 7 9 11

T2相应冷站

T2空调末端

T3相应冷站

T3空调末端

供冷季供热季供冷季过渡季过渡季

Ele

ctri

city

consu

mpti

on

(kW

h/m

2）

T2-Chiller+Pump

T2-AHU

T3-Chiller+Pump

T3-AHU

AC energy consumption of T3 is reduced by ~40%

28Zhao K, Liu XH, … Renewable & Sustainable Energy Reviews, 2016

Month


Further applications in terminals

29

Qingdao airport

~450,000 m2

2020

Chengdu airport

~500,000 m2

2021


1. Radiant floor helps to create a stratified

environment

2. Reducing transportation energy air → water

3. Achieving high temp. cooling and low temp. heating:

reducing energy of heating/cooling sources

5. Conclusion

30

Task: Reducing energy consumed in AT

Terminal solution for AT requires novel method

BUILT ENVIRONMENT FACING

CLIMATE CHANGE

THANKS

Dr. Xiaohua Liu

Tsinghua University

[email protected]

Diamond sponsors

radiant floor cooling and application in large-scale airport … · 2019. 7. 3. · radiant floor...

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