Thermoacoustic refrigeration part 2.

Hi folks!

This is the second step of my huge project of thermoacoustic refrigeration.
Today I'll show you my new engine's parts also the first test run and I'll draw the conclusions.

The engine is a standing wave type refrigerator.
Base parts:
- loudspeaker driver
- heat exchangers
- stack
- resonator
- amplifier
- PC, program
- digital thermometers
That's all!

My 180/120 W SAL XPRO 2060 loudspeaker is working in a closed
20 litres 250 mm diameter orange PVC tube box.



The other PVC tubes are 50 mm outside diameter.
The fittings and other parts dedicated for this diameter.
Easy to use them.

The heat exchangers from 0,4 mm holes, 0,063 mm wire, 75% relative open area copper mesh.
I stick together these with neutral silicon on a sticky tape base.
Layer by layer, nearly hole on hole.
That was a horrible slow and riski work.
:)



The stack was a rolled, parallel plate style stack with 0,4 mm gap. Length: 83 mm
Plastic sheet's 0,08 mm thick.



I used a new tech for spacing!
Sorry, I don't need to show it yet!
I hope you understand! :)
But this  technique is so different as sticked fishing line spacer.
It has more open area. :)

Amplifier is a KÖNIG 6000, 2x170W on 4 ohm.

Thermometers are HQ FT-10 stainless steel pin food thermometer,
the range of this thermometer is -50 to 300 C degrees.

The working frequency was 108 Hz,
sinus shaped wave
what I made with a small Hungarian language program they call it Jelgen.
So simple to use on any PC.

Resonator length was λ/2: 1,6 m

Experiment start at 22.7 degrees room temperature.
The hot side is going up pretty quikly, but after the cold side start to drop.
The cold side was loaded from the room across the copper heat exchanger,
 so the 17 degrees is good for first run.
The hot side hasn't enough cooling capacity, so there was a big temperature different.
Here is my video about this experiment,
Dont forget to vote it, and share it with your friends on your community sites please!


Much better performance with a new parallel plate stack:
Conclusions:

 The cooling capacity isn't enough on the hot side, so I'll change the heat exchanger soon for a better one.
After I want to reach the magic 0 degrees celsius!
:)
The stack performance was pretty good, but I need to change the length of it, 
also I need to change it for my new type parallel and pin array stack, 
and I need to check the differents in this atmospheric engine.

 Last performance on 27.05.2015. was only one degrees yet:
Later on...
A need to build a "Bellow Bounce" type refrigerator too, but not the infold version as Ben and Jerry's refrigerator.
My engine will be straight and I'll use a simple rubber boots accordion for bouncer.
It has lower frequency and the resonator length should be 1/50th of the wavelength!
Unbelievable thesis!

 See You Soon!
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Standing wave thermoacoustic engine with mechanical resonator

What is the mechanical resonator?

This is a simple solid piston with adjustable spring, or back buffer volume.
The mechanical resonator can replace the acoustic resonator easily.
"Simulation calculations show that the mechanical resonator dissipates 40 % less 
acoustic power than the acoustic one." 

Wouw! :)

How we can make one?
So simple but
some basic information first.

As you can see on this picture (FIG. 1), if you need to close a thermoacoustic standing wave engine, then the closed resonator part (right side) should be same length as left side, the sound generator base.
The whole system is a half wavelenght thermoacoustic engine.
The stack's center on the λ/8 exactly.

But what we can do with a mechanical resonator?
We can replace the whole resonator tube length( λ/4=4/8 of whole tube length) +  the volume between the cold heat exchanger to the resonator tube ( λ/16= 1/8 length).
So what we can do?
We can replace the whole length 5/8th part.
That is nearly 2/3 of full length!
After we get a short engine like this:

Where the 104 is a buffer volume. This volume help for the gas flow going trough the 112 stack
 also the 108-110 heat exchangers.
114 is the piston and the back side is a generator also "gas spring volume", or solid spring of course.

http://www.google.de/patents/US6578364

OK!
We know "everything" to make a simple TAMR.
:)

I made a short DIY video for you how do you make your first model from ordinary materials.



After I made another model from a big diameter test tube and accordion piston.
That was so speedy, strong and simple of course.



The engines frequency was lower than original because the weight/spring tension was different.
Not optimal, but the engines are works with an enough frequency for me.
:)
I hope you enjoyed!
Please share and vote my videos and subscribe my Youtube channel.
See you soon!
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