STRANGEST Piston Ever MADE!? - Near Isothermal Stirling Heat Pump

Fluid Mechanics has applied its near-isothermal technology to an existing heat pump cycle called the Stirling cycle. The Stirling cycle can be used for both heat engines and heat pumps. Currently the Stirling cycle only has niche heat pump applications such as cryocoolers (producing liquid nitrogen from air). By applying the near isothermal technology to the Stirling cycle, it is possible to make a heat pump which has similar heating/cooling capacity to the vapour compressor cycle while being significantly more energy efficient. Fluid Mechanics’ system is demonstrating potential efficiencies up to 75%, although in a practical machine efficiencies of between 50 to 60% of Carnot are expected.

[Dyusik]

Oh look, a 1980s ac compressor out of a jeep.

[EbenBransome]

Note that they claim an efficiency of 60% of Carnot. That is not 60% thermal efficiency. If you tried to use this thing for air conditioning the gain would be smaller than a standard heat pump.
This is a niche device for things like medical coolers, ice makers and the like.
By way of contrast a ship's Diesel engine may be 50% overall thermal efficiency - but 80% of Carnot efficiency.

[MaximumBan]

The key misleading fact is: "these fins have high thermal capacity".
Due to a high surface area, they have a high thermal exchange rate. The fins don't -hold- the thermal energy, but rather make is flow faster.

[Erhannis]

So glad to see somebody managed to fit even more marzel vanes on a retro encabulator

[paulpaulsen]

Sorry for correcting you: The fins for the thermal exchange need to have a high thermal conductivity, not capacity. Rocks have a very high thermal capacity, but it takes very long time to heat them up or they can keep the heat for long time

[AlexandarHullRichter]

the counterweights on the top of that thing are wild!

[stickyfox]

This is neat, but it's not new. In a Stirling engine this structure is called a regenerator, and it works by exchanging heat with the non-working volume of fluid that never gets pumped all the way into the other side of the engine. There's always going to be a little "dead space" in any reciprocating engine design, and in a Stirling engine the regenerator helps utilize the heat that's trapped there.

[mushcap]

I don't really understand most of what this means but I very much enjoy watching mechanical parts in motion.

[rtqii]

Swashplate internal combustion engines are used to power torpedoes. They burn Otto fuel which contains its own oxidizer.

[VyvienneEaux]

All the engineers crawled out of the woodworks for this one 😍

[MikhaelHausgeist]

It clearly have problems with vibration and mechanical complexity. Which means it be pricier than conventional heat pumps. As result it just don't competitive enough to be commercially reasonable to produce.

[ericchenard]

Thats nice to see old technology making a comeback to bettering are future

[catatonicbug]

As soon as they said that the motor was sealed inside the compartment, it made me question the maintenance process for that motor.

[LogicalQ]

Until one of those fins breaks from vibration and the whole thing fails catastrophically.

[Ireallycantthinkofahandle]

Seeing it spin makes me wanna dance with it

[christawilliams]

My 1984 Jeep Cherokee had an air conditioning compressor that looked like this one inside, except it was powered by a belt on the engine.

[FTributo]

That's the navigation device on the Lost in Space saucer. Dr Smith used it to make orange juice. That shifty bastard!

[simontautorat]

What is the true advantage of this System?
Is it really that much more efficient than cooling the compressed Medium after the compressor?

[eaglechawks]

I forsee long term reliability issues. It isn't more COST efficient if you are replacing it more often than a conventional unit.

[UnanimousDelivers]

So it's an isothermal encabulator?