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

Our group

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

Typical Research

300 Hz thermoacoustically-driven pulse tube cooler

Stirling-type pulse tube coolers Thermoacoustic generators （ including free piston Stirling generators）

Tc<80K

Heating

Thermoacoustically-driven pulse tube coolers

High frequency thermoacoustically-driven pulse tube coolers （ 300Hz ）

The standing-wave engine The pulse tube cooler

500W heating power ， 1W@80K

Traveling wave thermoacoustic engine driving traveling wave thermoacoustic cooler

Heating

Heatingpower 2.1kW, Cooling power 340W@-20℃， 410W@0 , on-going research include high frequency ℃ operation, impedance match, etc

10&20W@80K, relative Carnot efficiency around 20%, >100 Watt under development

High efficiency Stirling-type pulse tube cooler

Thermoacoustic generators

Free piston Stirling generators

Thermoacoustic Stirling heat engine-based generators

Double effect thermoacoustic generators

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

Free piston Stirling generators

100 We class 1kWe class, ~20% thermal to electric efficiency

Double effects thermoacoustic generators

Engine set with heat exchangers, regenerator and thermal buffer tube

Linear motor with double effect

pistons

Double effects thermoacoustic generators

Best results so far: nearly 2 kWe with 18% thermal to electric efficiency

TASHE loopResonance tube

Linear alternator

Thermoacoustic Stirling heat engine-based generators

System details

Engine Parameters:

17

Feedback tube

Main ambient

HX

regenerator Heaterblock

Thermal buffer

tube

Secondary ambient

HX

Resonancetube

Length (m)

1.55 0.05 0.08 0.06 0.24 0.02 4.45+1.0

Diameter (m)

0.1 0.08-0.3

Dmm

τN/A

KN/mm

Mkg

Rmech

N·s/mLs

mHrΩ

RΩ

60 102 171 0.93 15 264 3.7 60

Linear alternator Parameters:

Numerical Model

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2

ˆ ˆdpR U

dx

1 3

ˆˆˆ

dUR p R U

dx

1 2xdT

H c cdx

ˆ ˆ 0e eU R jX I

A

2

ˆ ˆ ˆm mR jXU I p

A A

Engine Model Generator Model

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

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.

20

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

Changing Piston diameter makes big difference

22

23

Changing Piston diameter makes big difference

24

Changing Piston diameter makes big difference

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

25

Experimental setup

26

TASHE loopLinear alternator

Resonance tube

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Experimental results

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

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

28

Thanks for your attention