Why aren't these compressors popular ?

[Poodle Head Mikey]

http://tinyurl.com/9tzcv99

[craig1]

Wow, I never knew they made those for refrigeration use. There's a company that makes low psi air compressors that work the same way and their reliability is light years ahead of the conventional piston compressors. A store I work for has had them on the air supplies for lobster tanks for 15 years now with no maintenance or failures. All the other stores are using more expensive conventional piston compressors that need to be replaced every 5 years and use almost 5 times more power.


Seems like a no brainer for refrigeration use.

[GT Jets]

Because they're teeny tiny........


GT

[Poodle Head Mikey]

How teeny tiny are they? Any word on the pumping capacity in BTU's?

PHM
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Because they're teeny tiny........


GT

[GT Jets]

Small enough to be powered by a 12VDC or 24VDC power source... Can't even venture a guess, but suspect it's under 2000 BTU's

GT

[Phase Loss]

If it can't chill my beers faster than I can drink them, I want no part of it.

[GT Jets]

If it can't chill my beers faster than I can drink them, I want no part of it.

[Poodle Head Mikey]

That answer doesn't mean shet. The electric starter motors that spin my 440 ci diesels are 12 volts too. And they are SAH not Small or low capacity. <g>

I guess I'll see if there is a way to contact Engel and ask them.

PHM
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Small enough to be powered by a 12VDC or 24VDC power source... Can't even venture a guess, but suspect it's under 2000 BTU's

GT

[GT Jets]

That answer doesn't mean shet. The electric starter motors that spin my 440 ci diesels are 12 volts too. And they are SAH not Small or low capacity. <g>

I guess I'll see if there is a way to contact Engel and ask them.

PHM
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and how many HOURS are on that starter? High torque items like a start only run a few seconds at a time, refrigeration compressors on the other hand, well, the opposite.

Be sure to update us on the max capacity. I does not impress me too much personally, but then again, who am I?

GT

[Poodle Head Mikey]

Isn't that a straw-man argument you are making? <g>

The compressors have one moving part. <g>

The "hours on the starter" has nothing to do with this discussion - which was about why the compressors are not commonly used. You suggested that it was due to them operating on a low voltage, such as 12 or 24 and so having low capacity. "Teeny-tiny" was the descriptive phrase. The reliability was never an issue.

PHM
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and how many HOURS are on that starter? High torque items like a start only run a few seconds at a time, refrigeration compressors on the other hand, well, the opposite.

Be sure to update us on the max capacity. I does not impress me too much personally, but then again, who am I?

GT

[timebuilder]

Isn't that a beer cooler in the upper RH corner?

I'd say that's a low capacity unit, like a sterling cooler.

[GT Jets]

Isn't that a straw-man argument you are making? <g>

The compressors have one moving part. <g>

The "hours on the starter" has nothing to do with this discussion - which was about why the compressors are not commonly used. You suggested that it was due to them operating on a low voltage, such as 12 or 24 and so having low capacity. "Teeny-tiny" was the descriptive phrase. The reliability was never an issue.

PHM
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PHM, I believe you are simply misunderstanding where I was coming from.

Being as the starter on your truck has a duty cycle of like .001%, it draws an incredible amount of amperage (read watts) for an extremely short (comparatively) amount of time.

A refrigeration compressor on the other hand has a duty cycle of say 90% if not 100%, which means it would have to draw very little current (again watts). So using this logic, it would have to have a relativity low HP, or small capacity, this compressor seems to have been developed specifically for portable refrigeration equipment. The company seems to be an automotive generator manufacturer.

Not trying to start a major debate, just wanted to make sure my point was clear.

GT

[Poodle Head Mikey]

Someone just told me that Engel has a patent on the compressor design and doesn't want to allow anyone else to make them. I guess that would explain why they aren't in common use. I wonder what triggers the power on and off the the wound coil?

[toocoolforschool]

They are not popular because they only last a couple of mths.

[motoguy128]

Wow, I never knew they made those for refrigeration use. There's a company that makes low psi air compressors that work the same way and their reliability is light years ahead of the conventional piston compressors. A store I work for has had them on the air supplies for lobster tanks for 15 years now with no maintenance or failures. All the other stores are using more expensive conventional piston compressors that need to be replaced every 5 years and use almost 5 times more power.


Seems like a no brainer for refrigeration use.

All aquarium air pumps since ohhh... 30 years ago when I started the hobby, used simple coils to move a diaphram "piston". I suspect it cycled at 60 Hz. SOme might have used 2 diaphrams, on on each end of the stroke.

Really, from that standpoint, the design is short sighted. It might as well have 2 cylinders, one at each end and just use a reed valve or similar as a check valve.

[motoguy128]

Someone just told me that Engel has a patent on the compressor design and doesn't want to allow anyone else to make them. I guess that would explain why they aren't in common use. I wonder what triggers the power on and off the the wound coil?

Probably SCR's (I think that's the term) some sort of solid state device similar to what's in an inverter. More similar I suppose to a Servo drive since it's a PM magnet for the stator. As stated in the mfg website, the stroke lenght and speed are vairable which allows low start-up load and I suppsoe also vairable compression ratio.

[craig1]

All aquarium air pumps since ohhh... 30 years ago when I started the hobby, used simple coils to move a diaphram "piston". I suspect it cycled at 60 Hz. SOme might have used 2 diaphrams, on on each end of the stroke.

The ones they had in these lobster tanks were huge compared to your standard aquarium pump. 3/4" air outlet and capable of about 30 PSI. When I looked them up on the Internet they showed how it worked and it was a Teflon coated floating piston the slid back and forth in a tube. Very cool design. Apparently most of these style pumps are used as septic tank aerators.

[motoguy128]

Small enough to be powered by a 12VDC or 24VDC power source... Can't even venture a guess, but suspect it's under 2000 BTU's

GT

At 12VDC< 100 Amps it's unreasonable for a constant load, with a peak load under 200 Amps with size 0 cables. So that's puts you at 1200Watts, or with a COP or 3, that's as much as 12,000 BTU's. BUt I think you'll be limited there. I think the small AC units that companies like Webasto make for sleeps babs are in the range of 6000-12000 BTU's.

[Poodle Head Mikey]

The company claims that they last for decades - with some still running since the 1960's.

Where did you get the information that they only last a few months?

PHM
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They are not popular because they only last a couple of mths.

[icemeister]

After a little digging, I found that this swing motor compressor has been made by Sawafuji in Japan, who purchased the licensing from its West German inventor in 1956. Apparently, Engel wasn't the only ones using it because Sawafuji also made mobile mini-fridges with the swing motor compressor and sold them in the USA under the name of Norcold.

They use an inverter to control the oscillating frequency to match that of the spring resonance in the motor.