1. Reporter :Ming-Che Chung
Date : 2014/04/08
Experimental study of heat transfer for supercritical carbon dioxide with upward flow in vertical tube
Reporter :Ming-Che Chung

2. Experimental apparatus and procedure
Outline
Background
Purpose
Experimental apparatus and procedure
Results
Conclusions
This is my outline. It includes five sections.
First one is the introduction, second is purpose,
third Experimental architecture , and next one is Experimental process planning , last is Future Works

3. Background A novel renewable energy concept is geothermal power.
Geothermal energy is the process of extracting the heat generation by earth and harnessing it to drive a power plant. 1

4. Traditional geothermal system Non-traditional geothermal system
Geothermal type
The geothermal system is divided into traditional geothermal system and non-traditional geothermal system.
Table.1. Geothermal system of classification
Geothermal system
System name
Temperature
Depth
Traditional geothermal system
Low temperature system
<100℃
1,000~2,000m
Middle temperature system
100~200℃
High temperature system
200~350℃
Non-traditional geothermal system
Enhanced geothermal system
100~300℃
3,000~5,000m 2

5. What is EGS ? Pump Seismometers Production well Injection well
CO2
Production well
Injection well
What is EGS ?
Artificial Fracture
CO2
CO2
Fig.1. Schematic diagram of EGS 3

6. Why use CO2 as working fluid?
Table.2. Comparison between Water and CO2
Brown propose that supercritical CO2 is use as working fluid in enhanced geothermal system.
Fluid property
Chemical
Water:
Powerful solvent for rock minerals: lots of potential for dissolution and precipitation.
CO2:
Not an ionic solvent; poor solvent for rock minerals.
Fluid circulation in wellbores
Small compressibility, moderate expansivity
Large compressibility and expansivity.
Ease of flow in reservoir
Higher viscosity, higher density
Lower viscosity, lower density
Heat transmission
Larger specific heat
Smaller specific heat
Why use CO2 as working fluid?
Solve the deep geothermal limit of water shortage
Special chemical properties
Thermosiphon can enhance efficiency
Sequestration for CO2 4

7. Purpose
For the reason of all of previous studies are limited by the absence of an experimental system to investigate the performance of supercritical CO2 in the reservoir.
This study determines the efficiency of heat extraction of supercritical CO2 in test section. 5

8. Experimental apparatus and procedure
Pressure set up
Test section heated
The operating condition achieved
Yes
Yes
Data collection
Steady state
CO2 injected
文獻蒐集>>由於澳洲對於EGS較早研究所以將澳洲的模擬與實驗做參考
物理模型建構>>建立一個尺度現地的模型
試驗系統設計>>試驗系統需要準備甚麼東西
實驗室取熱系統設置
Analysis
Fig.2. flow chart of experimental 6

9. Test section
 High pressure pump
Data logger
Heater
CO2 cylinder
Water bath
Fig.3. Schematic diagram of experimental system 7

10. Experimental conditions
Table.3. Operating conditions
Experimental conditions
Flow rate
10 mL/min、30 mL/min、40 mL/min、50 mL/min
Pressure
2000psi、1500psi、1100psi
Initial wall temperature
150℃、200℃ 8

11. 1.
where 𝑞 indicates the heat transfer rate of supercritical carbon dioxide, Qloss is heat loss. 2.
where 𝑚 indicates the mass flow rate, hin is the inlet enthalpy, hout is the outlet enthalpy. 3.
where ΔT1 indicates the temperature difference between inlet temperature and tube wall, ΔT2 is the temperature difference between outlet temperature and tube wall. 4.
where A is inner surface of test section. 9

12. Results

13. (a)
(b)
Fig.4. Effects of Reynolds number on the heat transfer coefficient(a) and heat transfer rate(b) at pressure=2000 psi and temperature=150℃. 10

14. non
(a)
(b)
Fig.5. Effects of pressure on the heat transfer coefficient(a) and heat transfer rate(b) at Re=7.6 and temperature=150℃. 11

15. (a)
(b)
Fig.6. Effects of temperature on the heat transfer coefficient(a) and heat transfer rate(b) at Re=6.3 and pressure=1100 psi.. 12

16. Conclusions
In this study, the heat extraction of supercritical CO2 is investigated by various experimental conditions. The results show that the heat transfer coefficient increases as the flow rate increases. Moreover, the excellent heat extraction is shown in 1500 psi. 13

17. Thank you for your attention