1. Electricity Generator and Other Research in Key Laboratory of Cryogenics of CAS
Wei Dai
Technical Institute of Physics and Chemistry,
Chinese Academy of Sciences，Beijing， China

2. Our group Prof. Ercang Luo and Wei Dai 5 other staff members
The group members:
Prof. Ercang Luo and Wei Dai
5 other staff members
>10 graduate students
Research Activity:
Coolers based on thermoacoustic cycles, down to 20 K
Thermoacoustics engines and generators, from
100We-3kWe, target bigger

3. Typical Research 300 Hz thermoacoustically-driven pulse tube cooler
Stirling-type pulse tube coolers
Thermoacoustic generators
（including free piston Stirling generators）

4. Thermoacoustically-driven pulse tube coolers
Tc<80K
Heating

5. High frequency thermoacoustically-driven pulse tube coolers（300Hz）
The pulse tube cooler
The standing-wave engine

6. 500W heating

7. Traveling wave thermoacoustic engine driving traveling wave thermoacoustic cooler
Heating

8. Heatingpower 2.1kW, Cooling power 340W@-20℃，
℃, on-going research include high frequency
operation, impedance match, etc

9. High efficiency Stirling-type pulse tube cooler
relative Carnot efficiency around 20%, >100 Watt under development

11. Thermoacoustic generators
Free piston Stirling generators
Thermoacoustic Stirling heat engine-based generators
Double effect thermoacoustic generators

12. Free piston Stirling generators
1.Hot heat exchanger 2.Regenerator 3.Ambient heat exchanger
4.Linear motor 5. Mechanical spring 6. Backside volume
7.Expansion space 8.Displacer 9.Compression space 10.Power piston

13. Free piston Stirling generators
100 We class kWe class, ~20%
thermal to electric efficiency

14. Double effects thermoacoustic generators
Engine set with heat exchangers, regenerator and thermal buffer tube
Linear motor with double effect
pistons

15. Double effects thermoacoustic generators
Best results so far: nearly 2 kWe with 18% thermal to electric efficiency

16. Thermoacoustic Stirling heat engine-based generators
TASHE loop
Resonance tube
Linear alternator

17. System details Engine Parameters: Linear alternator Parameters:
Feedback tube
Main ambient HX
regenerator
Heater block
Thermal buffer tube
Secondary ambient HX
Resonance tube
Length (m)
1.55
0.05
0.08
0.06
0.24
0.02
Diameter (m)
0.1
Linear alternator Parameters: D mm τ
N/A K
N/mm M kg
Rmech
N·s/m Ls mH r Ω R 60
102
171
0.93 15
264
3.7

18. Numerical Model
Engine Model
Generator Model

19. Comparison of the model with RC load to measure output
Computational and experimental data of the TASHE
(4MPa helium,75Hz working frequency, 650℃ heating temperature )

20. When it comes to a linear alternator, frequency coupling between the system working frequency (dominated by the engine) and the natural frequency of the linear alternator (dominated by its spring stiffness, moving mass, piston area) is crucial to the system performance.

21. Changing the natural frequency of the linear alternator makes big difference ( adjusting the moving mass)
6cm piston
The system stops working in this natural frequency range.
Computational results of power and pressure ratio as a function of the natural frequency of linear alternator (6cm piston diameter, 4.0 MPa helium, 650 oC heating temperature and 15 oC cooling water temperature).

22. Changing Piston diameter makes big difference

23. Changing Piston diameter makes big difference

24. Changing Piston diameter makes big difference

25. Changing the engine frequency makes big difference (mixing Argon with Helium)

26. Experimental setup
Resonance tube
TASHE loop
Linear alternator

27. Experimental results Best results：1 kWe output with 19%
thermal to electric efficiency

28. Solar-powered version, set up in Shen Zhen, China

29. Thanks for your attention