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7/31/2019 Profwei Dai
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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
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Our groupThe 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
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Typical Research
300 Hz thermoacoustically-driven pulse tube cooler
Stirling-type pulse tube coolers
Thermoacoustic generators including free piston Stirling generators
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Tc
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High frequency thermoacoustically-driven
pulse tube coolers 300Hz
The standing-wave engine The pulse tube cooler
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500W heating power 1W@80K
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Traveling wave thermoacoustic engine driving
traveling wave thermoacoustic cooler
Heating
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Heatingpower 2.1kW, Cooling power 340W@-20 410W@0 , on-going research include high frequency
operation, impedance match, etc
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10&20W@80K, relative Carnot efficiency around
20%, >100 Watt under development
High efficiency Stirling-type pulse tube cooler
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Thermoacoustic generators
Free piston Stirling generators
Thermoacoustic Stirling heat engine-based generators
Double effect thermoacoustic generators
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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
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Free piston Stirling generators
100 We class 1kWe class, ~20%
thermal to electric efficienc
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Double effects thermoacoustic generators
Engine set with heat
exchangers, regenerator and
thermal buffer tube
Linear motorwith double effect
pistons
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Double effects thermoacoustic generators
Best results so far: nearly 2 kWe
with 18% thermal to electric
efficiency
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TASHE loop
Resonance tube
Linear
alternator
Thermoacoustic Stirling heat engine-based generators
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Numerical Model
18
2
dpR U
dx=
1 3
dUR p R U
dx
= +
1 2
xdTH c cdx
= +
( )
0e eU R jX I A
+ =
( )2
m mR jXU I p
A A
+
+ =
Engine Model Generator Model
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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 )
19
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When it comes to a linear alternator, frequency
coupling between the system working frequency
(dominated by the engine) and the naturalfrequency of the linear alternator (dominated by its
spring stiffness, moving mass, piston area) is
crucial to the system performance.
20
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Changing the natural frequency of the linear alternator
makes big difference ( adjusting the moving mass)
21
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).
The system stops working in this
natural frequency range.
6cm piston
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Changing Piston diameter makes big difference
22
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Changing Piston diameter makes big difference
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Changing Piston diameter makes big difference
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Changing the engine frequency makes big difference
(mixing Argon with Helium)
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Experimental setup
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TASHE loop
Linear alternator
Resonance tube
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Experimental results
Best results 1 kWe output with 19%
thermal to electric efficiency
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Solar-powered version, set up in Shen Zhen, China
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Thanks for your attention