Do the model engineering fanatics ever build heat pumps? All I can recall
seeing are various engines.

I was trying to think up a project that would not look too eccentric and
would entertain people. It occurs to me that you could build a little
hand-cranked heat pump that would chill a beverage can from room temp down
to near freezing. Since that represents only about 50 BTUs it shouldn't
take that much muscle in a properly engineered device. It would all be
belt-driven from a hand crank, running something like a Procon pump to
compress a refrigerant, with a belt-driven fan over a condenser, and an
evaporator that was a saddle to hold a can sideways that was slowly spun.
The saddle could contain a water bath to make an ice bank to chill the can
without freezing it.

Or maybe just a simpler version to blow some cold air in your face when you
crank it.

Or what would be even more impressive would be a gadget that made cold beer
on one end and hot tea on the other.

"Richard J Kinch" wrote in message
.. .
Do the model engineering fanatics ever build heat pumps? All I can recall
seeing are various engines.

I was trying to think up a project that would not look too eccentric and
would entertain people. It occurs to me that you could build a little
hand-cranked heat pump that would chill a beverage can from room temp down
to near freezing. Since that represents only about 50 BTUs it shouldn't
take that much muscle in a properly engineered device. It would all be
belt-driven from a hand crank, running something like a Procon pump to
compress a refrigerant, with a belt-driven fan over a condenser, and an
evaporator that was a saddle to hold a can sideways that was slowly spun.
The saddle could contain a water bath to make an ice bank to chill the can
without freezing it.

Or maybe just a simpler version to blow some cold air in your face when
you
crank it.

Or what would be even more impressive would be a gadget that made cold
beer
on one end and hot tea on the other.

Stirling heat pump. They work great, and have fewer lubrication problems
than Stirling engines. And no stainless or superalloys. You can make them
out of aluminum screw-machine stock. One end is hot, the other end is cold.

I've had thoughts of making a Stirling cooler myself.

--
Ed Huntress

Richard J Kinch fired this volley in
:

Since that represents only about 50 BTUs it shouldn't
take that much muscle in a properly engineered device.

Richard, that would be roughly 1/4HP for five minutes.

That's a LOT of muscle.



LLoyd

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote:

Richard, that would be roughly 1/4HP for five minutes.

That's a LOT of muscle.

Learning how to do gross calculations really took a lot of fun out of pipe dreams

Wes

Richard J Kinch wrote:

Do the model engineering fanatics ever build heat pumps? All I can recall
seeing are various engines.

I was trying to think up a project that would not look too eccentric and
would entertain people. It occurs to me that you could build a little
hand-cranked heat pump that would chill a beverage can from room temp down
to near freezing. Since that represents only about 50 BTUs it shouldn't
take that much muscle in a properly engineered device. It would all be
belt-driven from a hand crank, running something like a Procon pump to
compress a refrigerant, with a belt-driven fan over a condenser, and an
evaporator that was a saddle to hold a can sideways that was slowly spun.
The saddle could contain a water bath to make an ice bank to chill the can
without freezing it.

Or maybe just a simpler version to blow some cold air in your face when you
crank it.

Or what would be even more impressive would be a gadget that made cold beer
on one end and hot tea on the other.

We have overblown project ideas on our to-do-who-knows-when lists. I
have a grand idea of converting a 3m sat dish into a parabolic solar
steam boiler to feed a steam engine generator followed by an absorption
chiller. Don't know if I'll ever get a round-tuit, but it's a neat idea.

"Pete C." wrote in
ster.com:


Richard J Kinch wrote:

Do the model engineering fanatics ever build heat pumps? All I can
recall seeing are various engines.

I was trying to think up a project that would not look too eccentric
and would entertain people. It occurs to me that you could build a
little hand-cranked heat pump that would chill a beverage can from
room temp down to near freezing. Since that represents only about 50
BTUs it shouldn't take that much muscle in a properly engineered
device. It would all be belt-driven from a hand crank, running
something like a Procon pump to compress a refrigerant, with a
belt-driven fan over a condenser, and an evaporator that was a saddle
to hold a can sideways that was slowly spun. The saddle could contain
a water bath to make an ice bank to chill the can without freezing
it.

Or maybe just a simpler version to blow some cold air in your face
when you crank it.

Or what would be even more impressive would be a gadget that made
cold beer on one end and hot tea on the other.

We have overblown project ideas on our to-do-who-knows-when lists. I
have a grand idea of converting a 3m sat dish into a parabolic solar
steam boiler to feed a steam engine generator followed by an
absorption chiller. Don't know if I'll ever get a round-tuit, but it's
a neat idea.

Why I was a lad, we had plans for a soda can "un-toaster". We had a
bunch of Peltier effect cooling modules from the local surplus yard, and
the idea was to make a clamping arrangement with four of them to suck the
heat out of a soda can. It would have drawn about 240 Watts. The
crowning touch was to be a lever arrangement to lower the can against a
spring so it would pop up when it was cool.

Many years later, I finally have an adequate shop & skills to build the
mechanism, but no time & no Peltier modules.

Doug White

Lloyd E. Sponenburgh writes:

Since that represents only about 50 BTUs it shouldn't
take that much muscle in a properly engineered device.

Richard, that would be roughly 1/4HP for five minutes.

1 KWH can pump 10,000 BTU in a 10 SEER heat pump. If we equate 746 watts to
1 HP, then you get 7460 BTUs pumped with 1 HP-hour. So pumping 50 BTUs
would take 50/7460 = 0.0067 HP-hour. That's about 0.08 HP for 5 minutes.
But who knows what efficiency you could build in that size. And how
thirsty you are for a cold one.

Richard J Kinch fired this volley in
:

1 KWH can pump 10,000 BTU in a 10 SEER heat pump. If we equate 746
watts to 1 HP, then you get 7460 BTUs pumped with 1 HP-hour. So
pumping 50 BTUs would take 50/7460 = 0.0067 HP-hour. That's about
0.08 HP for 5 minutes. But who knows what efficiency you could build
in that size. And how thirsty you are for a cold one.


I stand corrected. I failed to account for the fact that energy moved
isn't equal to energy input.

HOWSUMEVER... I'm not sure most 'mature' guys could output nearly a
tenth of a HP for five minutes, either. But I concede the error G.

LLoyd

On Thu, 03 Sep 2009 00:40:37 GMT, Doug White
wrote:

"Pete C." wrote in
nster.com:


Richard J Kinch wrote:

Do the model engineering fanatics ever build heat pumps? All I can
recall seeing are various engines.

I was trying to think up a project that would not look too eccentric
and would entertain people. It occurs to me that you could build a
little hand-cranked heat pump that would chill a beverage can from
room temp down to near freezing. Since that represents only about 50
BTUs it shouldn't take that much muscle in a properly engineered
device. It would all be belt-driven from a hand crank, running
something like a Procon pump to compress a refrigerant, with a
belt-driven fan over a condenser, and an evaporator that was a saddle
to hold a can sideways that was slowly spun. The saddle could contain
a water bath to make an ice bank to chill the can without freezing
it.

Or maybe just a simpler version to blow some cold air in your face
when you crank it.

Or what would be even more impressive would be a gadget that made
cold beer on one end and hot tea on the other.

We have overblown project ideas on our to-do-who-knows-when lists. I
have a grand idea of converting a 3m sat dish into a parabolic solar
steam boiler to feed a steam engine generator followed by an
absorption chiller. Don't know if I'll ever get a round-tuit, but it's
a neat idea.

Why I was a lad, we had plans for a soda can "un-toaster". We had a
bunch of Peltier effect cooling modules from the local surplus yard, and
the idea was to make a clamping arrangement with four of them to suck the
heat out of a soda can. It would have drawn about 240 Watts. The
crowning touch was to be a lever arrangement to lower the can against a
spring so it would pop up when it was cool.

Many years later, I finally have an adequate shop & skills to build the
mechanism, but no time & no Peltier modules.

Doug White
Sounds pretty much like the 60 Watt wine chiller I bought for $3 a
couple Saturdays back - took a 1 litre bottle of water from room
temperature to freezing in about 3 hours.
Gerry :-)}
London, Canada

On Sep 2, 11:03*pm, Gerald Miller wrote:
On Thu, 03 Sep 2009 00:40:37 GMT, Doug White
wrote:



"Pete C." wrote in
nster.com:

Richard J Kinch wrote:

Do the model engineering fanatics ever build heat pumps? *All I can
recall seeing are various engines.

I was trying to think up a project that would not look too eccentric
and would entertain people. *It occurs to me that you could build a
little hand-cranked heat pump that would chill a beverage can from
room temp down to near freezing. *Since that represents only about 50
BTUs it shouldn't take that much muscle in a properly engineered
device. *It would all be belt-driven from a hand crank, running
something like a Procon pump to compress a refrigerant, with a
belt-driven fan over a condenser, and an evaporator that was a saddle
to hold a can sideways that was slowly spun. The saddle could contain
a water bath to make an ice bank to chill the can without freezing
it.

Or maybe just a simpler version to blow some cold air in your face
when you crank it.

Or what would be even more impressive would be a gadget that made
cold beer on one end and hot tea on the other.

We have overblown project ideas on our to-do-who-knows-when lists. I
have a grand idea of converting a 3m sat dish into a parabolic solar
steam boiler to feed a steam engine generator followed by an
absorption chiller. Don't know if I'll ever get a round-tuit, but it's
a neat idea.

Why I was a lad, we had plans for a soda can "un-toaster". *We had a
bunch of Peltier effect cooling modules from the local surplus yard, and
the idea was to make a clamping arrangement with four of them to suck the
heat out of a soda can. *It would have drawn about 240 Watts. *The
crowning touch was to be a lever arrangement to lower the can against a
spring so it would pop up when it was cool.

Many years later, I finally have an adequate shop & skills to build the
mechanism, but no time & no Peltier modules.

Doug White

Sounds pretty much like the 60 Watt wine chiller I bought for $3 a
couple Saturdays back - took a 1 litre bottle of water from room
temperature to freezing in about 3 hours.
Gerry :-)}
London, Canada
Found
I have an old lab aparatus that believe it or not has the unfortunate
name silk screened on it of "Cold Generator". Found it in a pile of
junk heading to the dumpster at work years ago and saved it. Obviously
we can't generate "cold", only move heat energy from one place to
another, but in any case that's what it's labeled, and is complete
with a meter on the side with a scale labeled "relative cold". It's
a nicely made piece about 15" high of stainless, copper and Bakelite.
Weighs about 10 lbs, and has a clear Plexiglas dome on the top. When
hooked to a compressed air line it starts some kind of reciprocating
action and there is a knurled knob under the dome which goes up and
down probably once per second. The copper cylinder at the bottom
becomes very cold. I put 100 % Ethylene Glycol in a Dixie cup and
submerged the cylinder in it. After a few minutes the Glycol freezes
solid. Not sure if it's using the air as a working fluid or just for
power. Looks to be maybe '60s vintage. Kinda cool...last used it a
few months ago to freeze some Buna "O" rings for a project I was
working on. Might be some kind of Sterling pump.

Richard J Kinch wrote:

Lloyd E. Sponenburgh writes:

Since that represents only about 50 BTUs it shouldn't
take that much muscle in a properly engineered device.

Richard, that would be roughly 1/4HP for five minutes.

1 KWH can pump 10,000 BTU in a 10 SEER heat pump. If we equate 746 watts to
1 HP, then you get 7460 BTUs pumped with 1 HP-hour. So pumping 50 BTUs
would take 50/7460 = 0.0067 HP-hour. That's about 0.08 HP for 5 minutes.
But who knows what efficiency you could build in that size. And how
thirsty you are for a cold one.

300W continous out of the legs of a trained cyclist is a reasonable number.

56W hand cranking seems a bit ambitious.

I got it, bar stool with pedals

Wes

Neat idea.

The engineer in me says, "simplify". So, just build 1/2 a heat pump. If you
pull a vacuum on a properly selected fluid (IPA???) it will boil and cool.
So, all you'd need is a little vacuum pump and a double wall container sized
for a beer can.

I'd further consider a cylinder with "O" rings for seals and read valves.
Just move it back and forth for your power.


There's one concept anyway.

Karl

Karl Townsend writes:

If you
pull a vacuum on a properly selected fluid (IPA???) it will boil and
cool. So, all you'd need is a little vacuum pump and a double wall
container sized for a beer can.

If the fluid boils low enough (R134a etc) then you don't even need to pump
it. But that's cheating to vent the refrigerant. This is supposed to be a
closed system other than the crank input and heat output.

On 2009-09-03, Gerald Miller wrote:
On Thu, 03 Sep 2009 00:40:37 GMT, Doug White
wrote:


[ ... ]

Why I was a lad, we had plans for a soda can "un-toaster". We had a
bunch of Peltier effect cooling modules from the local surplus yard, and
the idea was to make a clamping arrangement with four of them to suck the
heat out of a soda can. It would have drawn about 240 Watts. The
crowning touch was to be a lever arrangement to lower the can against a
spring so it would pop up when it was cool.

Many years later, I finally have an adequate shop & skills to build the
mechanism, but no time & no Peltier modules.

Sounds pretty much like the 60 Watt wine chiller I bought for $3 a
couple Saturdays back - took a 1 litre bottle of water from room
temperature to freezing in about 3 hours.

Hmm ... glass container? Mess? (And what is the freezing point
of wine instead of water?)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On 4 Sep 2009 02:59:27 GMT, "DoN. Nichols"
wrote:

On 2009-09-03, Gerald Miller wrote:
On Thu, 03 Sep 2009 00:40:37 GMT, Doug White
wrote:


[ ... ]

Why I was a lad, we had plans for a soda can "un-toaster". We had a
bunch of Peltier effect cooling modules from the local surplus yard, and
the idea was to make a clamping arrangement with four of them to suck the
heat out of a soda can. It would have drawn about 240 Watts. The
crowning touch was to be a lever arrangement to lower the can against a
spring so it would pop up when it was cool.

Many years later, I finally have an adequate shop & skills to build the
mechanism, but no time & no Peltier modules.

Sounds pretty much like the 60 Watt wine chiller I bought for $3 a
couple Saturdays back - took a 1 litre bottle of water from room
temperature to freezing in about 3 hours.

Hmm ... glass container? Mess? (And what is the freezing point
of wine instead of water?)

Enjoy,
DoN.
I doubt that any ice would have formed - just held at 0 deg. C. I
haven't investigated the actual structure but the inner, metal cup
seems uniformly cold. Actually I bought it for the 12V, 5A power
supply.
Gerry :-)}
London, Canada

On Wed, 02 Sep 2009 21:38:15 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

Richard J Kinch fired this volley in
:

1 KWH can pump 10,000 BTU in a 10 SEER heat pump. If we equate 746
watts to 1 HP, then you get 7460 BTUs pumped with 1 HP-hour. So
pumping 50 BTUs would take 50/7460 = 0.0067 HP-hour. That's about
0.08 HP for 5 minutes. But who knows what efficiency you could build
in that size. And how thirsty you are for a cold one.


I stand corrected. I failed to account for the fact that energy moved
isn't equal to energy input.

HOWSUMEVER... I'm not sure most 'mature' guys could output nearly a
tenth of a HP for five minutes, either. But I concede the error G.

LLoyd

This 'mature' guy (AKA oldfart) survivor of quintuple bypass and now
bearer of an ICD can output rather more than 74.6 watts (0.1HP) for
considerably more than 5 minutes. I did better than that in rehab last
summer and I'm considerably stronger now than I was then.

I joked at the time that they tortured us pedalling furiously to
produce energy they sold to third-world places like Iowa.

On Wed, 02 Sep 2009 21:38:15 -0500, Lloyd E. Sponenburgh wrote:

Richard J Kinch fired this volley in
:

1 KWH can pump 10,000 BTU in a 10 SEER heat pump. If we equate 746
watts to 1 HP, then you get 7460 BTUs pumped with 1 HP-hour. So
pumping 50 BTUs would take 50/7460 = 0.0067 HP-hour. That's about
0.08 HP for 5 minutes. But who knows what efficiency you could build
in that size. And how thirsty you are for a cold one.


I stand corrected. I failed to account for the fact that energy moved
isn't equal to energy input.

HOWSUMEVER... I'm not sure most 'mature' guys could output nearly a
tenth of a HP for five minutes, either. But I concede the error G.


Hour-record cyclists put out something over half a KW for that hour.

75 watts for 5 minutes is more than button pushing on a remote, but not
that hard.

On Sep 2, 4:41*pm, Richard J Kinch wrote:
Do the model engineering fanatics ever build heat pumps? *All I can recall
seeing are various engines.

I was trying to think up a project that would not look too eccentric and
would entertain people. *It occurs to me that you could build a little
hand-cranked heat pump that would chill a beverage can from room temp down
to near freezing. *Since that represents only about 50 BTUs it shouldn't
take that much muscle in a properly engineered device. *It would all be
belt-driven from a hand crank, running something like a Procon pump to
compress a refrigerant, with a belt-driven fan over a condenser, and an
evaporator that was a saddle to hold a can sideways that was slowly spun. *
The saddle could contain a water bath to make an ice bank to chill the can
without freezing it.

Or maybe just a simpler version to blow some cold air in your face when you
crank it.

Or what would be even more impressive would be a gadget that made cold beer
on one end and hot tea on the other.

I've got a copy of a series that ran in The Model Engineer, late '30s
or '40s. Used methyl chloride for the working fluid and was just about
big enough to make an ice cube. An absorption unit would probably be
easier to build, once you can braze hydrogen-proof joints.

Stan

_ wrote:
On Wed, 02 Sep 2009 21:38:15 -0500, Lloyd E. Sponenburgh wrote:

Richard J Kinch fired this volley in
:

1 KWH can pump 10,000 BTU in a 10 SEER heat pump. If we equate 746
watts to 1 HP, then you get 7460 BTUs pumped with 1 HP-hour. So
pumping 50 BTUs would take 50/7460 = 0.0067 HP-hour. That's about
0.08 HP for 5 minutes. But who knows what efficiency you could build
in that size. And how thirsty you are for a cold one.

I stand corrected. I failed to account for the fact that energy moved
isn't equal to energy input.

HOWSUMEVER... I'm not sure most 'mature' guys could output nearly a
tenth of a HP for five minutes, either. But I concede the error G.


Hour-record cyclists put out something over half a KW for that hour.

75 watts for 5 minutes is more than button pushing on a remote, but not
that hard.

Everything is easy for the man that never does it.

--Winston

Winston fired this volley in news:h7rknb02j66
@news7.newsguy.com:


Everything is easy for the man that never does it.


Especially considering that so far, we've only accounted for the heat.
Assuming a perfect Stirling machine is about 54% efficient, how much work
do you think we'll have to add for losses to get the delta-T desired?

LLoyd

On Wed, 02 Sep 2009 23:03:43 -0400, Gerald Miller wrote:
On Thu, 03 Sep 2009 00:40:37 GMT, Doug White wrote:

Many years later, I finally have an adequate shop & skills to build the
mechanism, but no time & no Peltier modules.

Sounds pretty much like the 60 Watt wine chiller I bought for $3 a couple
Saturdays back - took a 1 litre bottle of water from room temperature to
freezing in about 3 hours. Gerry :-)}

A wine chiller that goes below freezing probably won't be too
wine-friendly. ;-)

Cheers!
Rich

Pete C. wrote:

We have overblown project ideas on our to-do-who-knows-when lists. I
have a grand idea of converting a 3m sat dish into a parabolic solar
steam boiler to feed a steam engine generator followed by an absorption
chiller. Don't know if I'll ever get a round-tuit, but it's a neat idea.

Much better to run a high temp differential Stirling engine off solar
input. A polished 3 M dish can melt steel in seconds at the focus. A
pretty small Stirling engine can deliver a lot of power if you compress
the working fluid, and use either Helium or Hydrogen, instead of air.
There are tricks (called the Heylandt crown) to keep the hot gas off the
seals, so all the seals run at modest temperature. Then you can use
teflon-bearing seal material for piston rings, and put sealed ball
bearings on the mains and rods. This allows you to have no liquid lube
in the engine, so oil mist won't coke up in the heater tubes. You want
to run the heater tubes as hot as your materials can stand, like 600 -800 C.

You can build a hermetic machine, and put a little brushless PM
alternator inside the crankcase. Drive whatever you want with the
electrical output.

Jon

"Jon Elson" wrote in message
...
Pete C. wrote:

We have overblown project ideas on our to-do-who-knows-when lists. I
have a grand idea of converting a 3m sat dish into a parabolic solar
steam boiler to feed a steam engine generator followed by an absorption
chiller. Don't know if I'll ever get a round-tuit, but it's a neat idea.

Much better to run a high temp differential Stirling engine off solar
input. A polished 3 M dish can melt steel in seconds at the focus. A
pretty small Stirling engine can deliver a lot of power if you compress
the working fluid, and use either Helium or Hydrogen, instead of air.
There are tricks (called the Heylandt crown) to keep the hot gas off the
seals, so all the seals run at modest temperature. Then you can use
teflon-bearing seal material for piston rings, and put sealed ball
bearings on the mains and rods. This allows you to have no liquid lube in
the engine, so oil mist won't coke up in the heater tubes. You want to
run the heater tubes as hot as your materials can stand, like 600 -800 C.

You can build a hermetic machine, and put a little brushless PM alternator
inside the crankcase. Drive whatever you want with the
electrical output.

Jon

But...but...if the object is a cooler, it's SO much simpler to build the
Stirling as a cooler rather than as an engine. No lube problems, no material
problems, and they run well on air if you aren't going for cryocooling.

Of course, you need a way to drive it, and if you aren't going to use an
electric motor, and if you're really ambitious, you could use a Stirling
motor. But what you're describing is a WHOLE lot more hassle than a small
Stirling cooler.

--
Ed Huntress

Lloyd E. Sponenburgh writes:

Assuming a perfect Stirling machine is about 54% efficient, how much
work do you think we'll have to add for losses to get the delta-T
desired?

My calculations for a conventional compressor assumed the efficiency of a
10 SEER air conditioner, which also has the losses of the electrical motor
and the air handler fan to overcome to get to that 10 SEER, which the beer
can chiller doesn't. I don't know if scaling things down makes them more
or less efficient, or how much so.

On 2009-09-04, Ed Huntress wrote:

"Jon Elson" wrote in message
...
Pete C. wrote:

We have overblown project ideas on our to-do-who-knows-when lists. I
have a grand idea of converting a 3m sat dish into a parabolic solar
steam boiler to feed a steam engine generator followed by an absorption
chiller. Don't know if I'll ever get a round-tuit, but it's a neat idea.

Much better to run a high temp differential Stirling engine off solar
input. A polished 3 M dish can melt steel in seconds at the focus. A

[ ... ]

You can build a hermetic machine, and put a little brushless PM alternator
inside the crankcase. Drive whatever you want with the
electrical output.

[ ... ]

But...but...if the object is a cooler, it's SO much simpler to build the
Stirling as a cooler rather than as an engine. No lube problems, no material
problems, and they run well on air if you aren't going for cryocooling.

What about a vortex cooler -- no moving parts (unless you count
the air). A bit noisy, however. :-)

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote in message
...
On 2009-09-04, Ed Huntress wrote:

"Jon Elson" wrote in message
...
Pete C. wrote:

We have overblown project ideas on our to-do-who-knows-when lists. I
have a grand idea of converting a 3m sat dish into a parabolic solar
steam boiler to feed a steam engine generator followed by an absorption
chiller. Don't know if I'll ever get a round-tuit, but it's a neat
idea.

Much better to run a high temp differential Stirling engine off solar
input. A polished 3 M dish can melt steel in seconds at the focus. A

[ ... ]

You can build a hermetic machine, and put a little brushless PM
alternator
inside the crankcase. Drive whatever you want with the
electrical output.

[ ... ]

But...but...if the object is a cooler, it's SO much simpler to build the
Stirling as a cooler rather than as an engine. No lube problems, no
material
problems, and they run well on air if you aren't going for cryocooling.

What about a vortex cooler -- no moving parts (unless you count
the air). A bit noisy, however. :-)

Enjoy,
DoN.

Those darned things still confuse me. I've never looked closely enough to
figure out how they really work, aside from the simple expansion of air and
its consequent absorption of heat. But there's more to it, I think.

Anyway, without knowing anything about their thermodynamic efficiency, yes,
they sure look appealing from a simplicity standpoint.

--
Ed Huntress

On Sat, 5 Sep 2009 01:56:25 -0400, "Ed Huntress"
wrote:


"DoN. Nichols" wrote in message
...



What about a vortex cooler -- no moving parts (unless you count
the air). A bit noisy, however. :-)

Enjoy,
DoN.

Those darned things still confuse me. I've never looked closely enough to
figure out how they really work, aside from the simple expansion of air and
its consequent absorption of heat. But there's more to it, I think.

Anyway, without knowing anything about their thermodynamic efficiency, yes,
they sure look appealing from a simplicity standpoint.

Look up Hilsch Vortex tube.

They are hideously inefficient, relying as they do, on Maxwell's Demon to
separate fast and slow molecules.


Mark Rand
RTFM

On 2009-09-05, Ed Huntress wrote:

"DoN. Nichols" wrote in message
...

[ ... ]

What about a vortex cooler -- no moving parts (unless you count
the air). A bit noisy, however. :-)

[ ... ]

Those darned things still confuse me. I've never looked closely enough to
figure out how they really work, aside from the simple expansion of air and
its consequent absorption of heat. But there's more to it, I think.

Note that there are two ends to it, and cold air comes out one
end, and hot air out the other.

Essentially, compressed air is fed in tangentially around a
point just past the junction of a disk and a large diameter tube. In
the center of the disk is a smaller hole, going off to a tube in the
other direction. The larger tube has an obstruction at a distance so
the total area is similar to the smaller tube (and I think ideally the
larger tube has twice the area of the smaller tube).

The tangential feed causes the air to form a spinning disc at
that point. Hotter air has molecules in faster motion than colder air,
so the hotter molecules tend to (on average) collect around the OD of
the spinning disc of air, and the colder molecules migrate to the
center. Since there is only one direction the hotter molecules can go
(down the larger tube) and while there are two directions the colder air
can go, most of the hotter air from the compressor is going down the
larger tube, so the pressure is a bit higher there, and the colder air
mostly goes down the smaller diameter tube. (It might be possible to
make it more efficient by putting a blocking disc near the center on the
hot side so the colder air can't go that way readily.

I made one of these a long time ago, using mostly plumbing
fittings and a bit of turned and machined brass after seeing one in a
demo of the things one of the other labs in the area was developing.
(The air from the cold side was piped into the helmets of tank crew,
especially those who are trapped down inside the tank during normal
operation.)

Anyway, without knowing anything about their thermodynamic efficiency, yes,
they sure look appealing from a simplicity standpoint.

What I made was terribly inefficient -- it took a lot of
compressed air to get a reasonable separation between hot and cold
output -- but the hot side pipe was uncomfortable to hold, and the cold
side was quite pleasant in mid summer. I understand that the main
things against them are the noise output and the relatively poor
efficiency. But in a tank, there is energy to spare, and an already
noisy environment, so the cooling is quite welcome.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote in message
...
On 2009-09-05, Ed Huntress wrote:

"DoN. Nichols" wrote in message
...

[ ... ]

What about a vortex cooler -- no moving parts (unless you count
the air). A bit noisy, however. :-)

[ ... ]

Those darned things still confuse me. I've never looked closely enough to
figure out how they really work, aside from the simple expansion of air
and
its consequent absorption of heat. But there's more to it, I think.

Note that there are two ends to it, and cold air comes out one
end, and hot air out the other.

Essentially, compressed air is fed in tangentially around a
point just past the junction of a disk and a large diameter tube. In
the center of the disk is a smaller hole, going off to a tube in the
other direction. The larger tube has an obstruction at a distance so
the total area is similar to the smaller tube (and I think ideally the
larger tube has twice the area of the smaller tube).

The tangential feed causes the air to form a spinning disc at
that point. Hotter air has molecules in faster motion than colder air,
so the hotter molecules tend to (on average) collect around the OD of
the spinning disc of air, and the colder molecules migrate to the
center. Since there is only one direction the hotter molecules can go
(down the larger tube) and while there are two directions the colder air
can go, most of the hotter air from the compressor is going down the
larger tube, so the pressure is a bit higher there, and the colder air
mostly goes down the smaller diameter tube. (It might be possible to
make it more efficient by putting a blocking disc near the center on the
hot side so the colder air can't go that way readily.

I made one of these a long time ago, using mostly plumbing
fittings and a bit of turned and machined brass after seeing one in a
demo of the things one of the other labs in the area was developing.
(The air from the cold side was piped into the helmets of tank crew,
especially those who are trapped down inside the tank during normal
operation.)

Anyway, without knowing anything about their thermodynamic efficiency,
yes,
they sure look appealing from a simplicity standpoint.

What I made was terribly inefficient -- it took a lot of
compressed air to get a reasonable separation between hot and cold
output -- but the hot side pipe was uncomfortable to hold, and the cold
side was quite pleasant in mid summer. I understand that the main
things against them are the noise output and the relatively poor
efficiency. But in a tank, there is energy to spare, and an already
noisy environment, so the cooling is quite welcome.

Enjoy,
DoN.

That was a valiant effort, but I think I need a diagram. g I'll put it on
my short list of things to look into. As you describe it, it does sound
intriguing.

Thanks.

--
Ed Huntress

"Mark Rand" wrote in message
...
On Sat, 5 Sep 2009 01:56:25 -0400, "Ed Huntress"
wrote:


"DoN. Nichols" wrote in message
...



What about a vortex cooler -- no moving parts (unless you count
the air). A bit noisy, however. :-)

Enjoy,
DoN.

Those darned things still confuse me. I've never looked closely enough to
figure out how they really work, aside from the simple expansion of air
and
its consequent absorption of heat. But there's more to it, I think.

Anyway, without knowing anything about their thermodynamic efficiency,
yes,
they sure look appealing from a simplicity standpoint.

Look up Hilsch Vortex tube.

They are hideously inefficient, relying as they do, on Maxwell's Demon to
separate fast and slow molecules.


Mark Rand
RTFM

Thanks, Mark. I'll put it on my list of things to check into.

--
Ed Huntress

In article ,
"Ed Huntress" wrote:

"Mark Rand" wrote in message
...
On Sat, 5 Sep 2009 01:56:25 -0400, "Ed Huntress"
wrote:


"DoN. Nichols" wrote in message
...



What about a vortex cooler -- no moving parts (unless you count
the air). A bit noisy, however. :-)

Enjoy,
DoN.

Those darned things still confuse me. I've never looked closely enough to
figure out how they really work, aside from the simple expansion of air
and
its consequent absorption of heat. But there's more to it, I think.

Anyway, without knowing anything about their thermodynamic efficiency,
yes,
they sure look appealing from a simplicity standpoint.

Look up Hilsch Vortex tube.

They are hideously inefficient, relying as they do, on Maxwell's Demon to
separate fast and slow molecules.


Mark Rand
RTFM

Thanks, Mark. I'll put it on my list of things to check into.

http://en.wikipedia.org/wiki/Vortex_tube

Joe Gwinn

"Joseph Gwinn" wrote in message
...
In article ,
"Ed Huntress" wrote:

"Mark Rand" wrote in message
...
On Sat, 5 Sep 2009 01:56:25 -0400, "Ed Huntress"

wrote:


"DoN. Nichols" wrote in message
...



What about a vortex cooler -- no moving parts (unless you count
the air). A bit noisy, however. :-)

Enjoy,
DoN.

Those darned things still confuse me. I've never looked closely enough
to
figure out how they really work, aside from the simple expansion of air
and
its consequent absorption of heat. But there's more to it, I think.

Anyway, without knowing anything about their thermodynamic efficiency,
yes,
they sure look appealing from a simplicity standpoint.

Look up Hilsch Vortex tube.

They are hideously inefficient, relying as they do, on Maxwell's Demon
to
separate fast and slow molecules.


Mark Rand
RTFM

Thanks, Mark. I'll put it on my list of things to check into.

http://en.wikipedia.org/wiki/Vortex_tube

Joe Gwinn

Aha. Well, that helps. Thanks, Joe.

It appears from that description that there is some controversy about the
best way to describe it. That sounds like the controversy over the Bernoulli
Principle and the lift on an aircraft wing. You just pick the explanation
that works for you. g

I'll have to dig further. Again, I appreciate the link.

--
Ed Huntress

"jk" wrote in message
...
"Ed Huntress" wrote:


It appears from that description that there is some controversy about the
best way to describe it. That sounds like the controversy over the
Bernoulli
Principle and the lift on an aircraft wing. You just pick the explanation
that works for you. g


I don't care if the explanation works for me, as long as it works for
the airplane
jk

g Yes. It must be an awful feeling to be doing some calculations at 30,000
feet and to conclude that the plane can't possibly fly...

--
Ed Huntress

"Ed Huntress" wrote:


It appears from that description that there is some controversy about the
best way to describe it. That sounds like the controversy over the Bernoulli
Principle and the lift on an aircraft wing. You just pick the explanation
that works for you. g


I don't care if the explanation works for me, as long as it works for
the airplane
jk

"Richard J Kinch" wrote in message
.. .
Do the model engineering fanatics ever build heat pumps? All I can recall
seeing are various engines.

I was trying to think up a project that would not look too eccentric and
would entertain people. It occurs to me that you could build a little
hand-cranked heat pump that would chill a beverage can from room temp down
to near freezing. Since that represents only about 50 BTUs it shouldn't
take that much muscle in a properly engineered device. It would all be
belt-driven from a hand crank, running something like a Procon pump to
compress a refrigerant, with a belt-driven fan over a condenser, and an
evaporator that was a saddle to hold a can sideways that was slowly spun.
The saddle could contain a water bath to make an ice bank to chill the can
without freezing it.

Or maybe just a simpler version to blow some cold air in your face when
you
crank it.

Or what would be even more impressive would be a gadget that made cold
beer
on one end and hot tea on the other.

http://www.youtube.com/watch?v=wpEG0...eature=related

Rick writes:

http://www.youtube.com/watch?v=wpEG0...eature=related

Cute, but that's cheating, using a dessicant to do most of the work.

"Richard J Kinch" wrote in message
. ..
Rick writes:

http://www.youtube.com/watch?v=wpEG0...eature=related

Cute, but that's cheating, using a dessicant to do most of the work.

I agree, not quite what you were asking about...