are a bit useless, as when you need most heat, they work less well
and at about minus 5, pack in altogether. This down to the
refrigerant gas used.

However there is a new technolgy one out now, runs on CO2 refrigerant
and works to much lower outdoor temperatures. Sanyo.


http://www.airconwarehouse.com/acata...O_Brochure.pdf

In article ,
harry writes:
are a bit useless, as when you need most heat, they work less well
and at about minus 5, pack in altogether. This down to the
refrigerant gas used.

No it's not, it's down to the outside unit (evaporator) icing up.
Mine won't work effectively between about +5C and 0C outside because
it has to keep running defrost cycles, but once it's got down to -2C
and lower, it again works fine, because most of the moisture has
already dropped out of the air by then as frost or frozen fog, and
doesn't clog the evaporator. IIRC, I tried it down to something
like -8 or -10, and it still chucks out lots of heat inside.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Jun 22, 6:01 am, harry wrote:
are a bit useless, as when you need most heat, they work less well
and at about minus 5, pack in altogether. This down to the
refrigerant gas used.

However there is a new technolgy one out now, runs on CO2 refrigerant
and works to much lower outdoor temperatures. Sanyo.

http://www.airconwarehouse.com/acata...O_Brochure.pdf

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

On Jun 21, 10:37*pm, (Andrew Gabriel)
wrote:
In article ,
* * * * harry writes:

are a bit useless, as when you need *most heat, they work less well
and at about minus 5, pack in altogether. *This down to the
refrigerant gas used.

No it's not, it's down to the outside unit (evaporator) icing up.
Mine won't work effectively between about +5C and 0C outside because
it has to keep running defrost cycles, but once it's got down to -2C
and lower, it again works fine, because most of the moisture has
already dropped out of the air by then as frost or frozen fog, and
doesn't clog the evaporator. *IIRC, I tried it down to something
like -8 or -10, and it still chucks out lots of heat inside.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

You need one that has a defrost cycle. Or rmaybe it has and is
malfunctioning.

harry wrote:

Andrew Gabriel wrote:

Mine [...] has to keep running defrost cycles

You need one that has a defrost cycle.

Errrr ...

On Jun 21, 10:37*pm, (Andrew Gabriel)
wrote:
In article ,
* * * * harry writes:

are a bit useless, as when you need *most heat, they work less well
and at about minus 5, pack in altogether. *This down to the
refrigerant gas used.

No it's not, it's down to the outside unit (evaporator) icing up.
Mine won't work effectively between about +5C and 0C outside because
it has to keep running defrost cycles, but once it's got down to -2C
and lower, it again works fine, because most of the moisture has
already dropped out of the air by then as frost or frozen fog, and
doesn't clog the evaporator. *IIRC, I tried it down to something
like -8 or -10, and it still chucks out lots of heat inside.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Found some more info about your problem. Sounds like your outside HX
(evaporator) is under sized, ie a bad installation. A larger one would
not run as cold and the icing up would be eliminated.
Good info here.

http://www.ethical-junction.org/blogs/2010/10/13/common-problems-with-air-source-heat-pumps/

On Jun 22, 7:09*am, Andy Burns wrote:
harry wrote:
Andrew Gabriel wrote:

Mine [...] has to keep running defrost cycles

You need one that has a defrost cycle.

Errrr ...

Sorry about that. Mind glitch.

harry wrote:
On Jun 22, 7:09 am, Andy Burns wrote:
harry wrote:
Andrew Gabriel wrote:
Mine [...] has to keep running defrost cycles
You need one that has a defrost cycle.
Errrr ...

Sorry about that. Mind glitch.

What mind?

"Matty F" wrote in message
...
On Jun 22, 6:01 am, harry wrote:
are a bit useless, as when you need most heat, they work less well
and at about minus 5, pack in altogether. This down to the
refrigerant gas used.

However there is a new technolgy one out now, runs on CO2 refrigerant
and works to much lower outdoor temperatures. Sanyo.

http://www.airconwarehouse.com/acata...O_Brochure.pdf

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.

On Jun 22, 9:14 am, The Natural Philosopher
wrote:
harry wrote:
On Jun 22, 7:09 am, Andy Burns wrote:
harry wrote:
Andrew Gabriel wrote:
Mine [...] has to keep running defrost cycles
You need one that has a defrost cycle.
Errrr ...

Sorry about that. Mind glitch.

What mind?

never mind

On Jun 22, 8:37 pm, "dennis@home"
wrote:
"Matty F" wrote in message

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.

It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

On Wed, 22 Jun 2011 01:57:26 -0700 (PDT), Matty F wrote:

It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

I can see the thinking but it can't be that simple can it?

Yes when you compress air it gets hot so extract that heat before
letting it go outside. But where has the energy that has made the air
hot come from? Do you get significantly more energy out of your "hot
air cooling radiator" than you have put in via the compressor?

--
Cheers
Dave.

dennis@home wrote:


"Matty F" wrote in message
...
On Jun 22, 6:01 am, harry wrote:
are a bit useless, as when you need most heat, they work less well
and at about minus 5, pack in altogether. This down to the
refrigerant gas used.

However there is a new technolgy one out now, runs on CO2 refrigerant
and works to much lower outdoor temperatures. Sanyo.

http://www.airconwarehouse.com/acata...O_Brochure.pdf

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.



The universe is a closed system, sufficient to the needs of this
particular application.

Dave Liquorice wrote:
On Wed, 22 Jun 2011 01:57:26 -0700 (PDT), Matty F wrote:

It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

I can see the thinking but it can't be that simple can it?

Yes when you compress air it gets hot so extract that heat before
letting it go outside. But where has the energy that has made the air
hot come from? Do you get significantly more energy out of your "hot
air cooling radiator" than you have put in via the compressor?

well there's the rub!

"The Natural Philosopher" wrote in message
...
dennis@home wrote:


"Matty F" wrote in message
...
On Jun 22, 6:01 am, harry wrote:
are a bit useless, as when you need most heat, they work less well
and at about minus 5, pack in altogether. This down to the
refrigerant gas used.

However there is a new technolgy one out now, runs on CO2 refrigerant
and works to much lower outdoor temperatures. Sanyo.

http://www.airconwarehouse.com/acata...O_Brochure.pdf

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.



The universe is a closed system, sufficient to the needs of this
particular application.

Look.. we already know you don't do physics so don't bother answering.

On Jun 22, 9:15 pm, "Dave Liquorice"
wrote:
On Wed, 22 Jun 2011 01:57:26 -0700 (PDT), Matty F wrote:
It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

I can see the thinking but it can't be that simple can it?

Yes when you compress air it gets hot so extract that heat before
letting it go outside. But where has the energy that has made the air
hot come from? Do you get significantly more energy out of your "hot
air cooling radiator" than you have put in via the compressor?

I believe we are on to something here. The motor of course uses
energy. I'd have a motor that uses about a kilowatt and compress air
from inside the house and run that through radiators, then outside to
a nozzle where the air escapes and gets very cold. Need to allow for
icing up, and the hissing noise it would make.
My house is leaky enough that more air will come back in.
Or air could be piped in past a radiator.
I don't need a lot of heating. It's winter here and I have not used a
heater so far this year.

"Matty F" wrote in message
...
On Jun 22, 8:37 pm, "dennis@home"
wrote:
"Matty F" wrote in message

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.

It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

No..
to collect heat from the outside it has to expand and cool below ambient
temperature.
It then heats up in the heat exchanger that is outside.

You then compress it which makes it hotter and push it through the internal
heat exchanger where it cools.

Then you expand it again, repeating as required.


Now it would be possible to take in fresh air, expand it to cool, heat it in
the heat exchanger and then compress it and release it in the inside
exchanger.
However it has problems, including..

no lubrication for instance unless you plan on throwing away the oil every
cycle.
condensation inside the expansion vessel as it cools.
noise caused by the release of the compressed air.
more difficult to control the flow rates so the air expands/compresses in
the right place.

On Jun 22, 11:40*am, "dennis@home"
wrote:
"Matty F" wrote in message

...

On Jun 22, 8:37 pm, "dennis@home"
wrote:
"Matty F" wrote in message

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.

It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

No..
to collect heat from the outside it has to expand and cool below ambient
temperature.
It then heats up in the heat exchanger that is outside.

You then compress it which makes it hotter and push it through the internal
heat exchanger where it cools.

Then you expand it again, repeating as required.

Now it would be possible to take in fresh air, expand it to cool, heat it in
the heat exchanger and then compress it and release it in the inside
exchanger.
However it has problems, including..

no lubrication for instance unless you plan on throwing away the oil every
cycle.
condensation inside the expansion vessel as it cools.
noise caused by the release of the compressed air.
more difficult to control the flow rates so the air expands/compresses in
the right place.

I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas condenses, the latent heat absorbs most of the
energy.

dennis@home wrote:


"The Natural Philosopher" wrote in message
...
dennis@home wrote:


"Matty F" wrote in message
...

On Jun 22, 6:01 am, harry wrote:
are a bit useless, as when you need most heat, they work less well
and at about minus 5, pack in altogether. This down to the
refrigerant gas used.

However there is a new technolgy one out now, runs on CO2 refrigerant
and works to much lower outdoor temperatures. Sanyo.

http://www.airconwarehouse.com/acata...O_Brochure.pdf

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.



The universe is a closed system, sufficient to the needs of this
particular application.

Look.. we already know you don't do physics so don't bother answering.
Talking to yourself again?

Matty F wrote:
On Jun 22, 9:15 pm, "Dave Liquorice"
wrote:
On Wed, 22 Jun 2011 01:57:26 -0700 (PDT), Matty F wrote:
It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.
I can see the thinking but it can't be that simple can it?

Yes when you compress air it gets hot so extract that heat before
letting it go outside. But where has the energy that has made the air
hot come from? Do you get significantly more energy out of your "hot
air cooling radiator" than you have put in via the compressor?

I believe we are on to something here. The motor of course uses
energy. I'd have a motor that uses about a kilowatt and compress air
from inside the house and run that through radiators, then outside to
a nozzle where the air escapes and gets very cold. Need to allow for
icing up, and the hissing noise it would make.
My house is leaky enough that more air will come back in.
Or air could be piped in past a radiator.
I don't need a lot of heating. It's winter here and I have not used a
heater so far this year.
you ill indeed see gains. The clue is that the air going out is colder
than outside.

It is in fact an air sourced heatpump.


Instead if the 'warm' air heating the regfrigerant you simply use the
warm air outside itself.

Tim Streater wrote:
In article
,
Matty F wrote:

On Jun 22, 8:37 pm, "dennis@home"
wrote:
"Matty F" wrote in message

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.

It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

Which will enter from the outside and so will be cold.

But not as cold as the escaping air from the outlet.

"The Natural Philosopher" wrote in message
...
Tim Streater wrote:
In article
,
Matty F wrote:

On Jun 22, 8:37 pm, "dennis@home"
wrote:
"Matty F" wrote in message

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.

It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

Which will enter from the outside and so will be cold.

But not as cold as the escaping air from the outlet.

See, I said you didn't do the physics as is obvious from your posts.
Now go and look at what heat pumps do and stop answering with wrong answers.

dennis@home wrote:


"The Natural Philosopher" wrote in message
...
Tim Streater wrote:
In article
,
Matty F wrote:

On Jun 22, 8:37 pm, "dennis@home"
wrote:
"Matty F" wrote in message

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the
other.

It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

Which will enter from the outside and so will be cold.

But not as cold as the escaping air from the outlet.

See, I said you didn't do the physics as is obvious from your posts.
Now go and look at what heat pumps do and stop answering with wrong
answers.
talking to yourself again?

On Jun 23, 3:36 am, harry wrote:
On Jun 22, 11:40 am, "dennis@home"
wrote:



"Matty F" wrote in message

...

On Jun 22, 8:37 pm, "dennis@home"
wrote:
"Matty F" wrote in message

Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.

It needs to be a closed cycle to pump heat from one side to the other.

It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.

No..
to collect heat from the outside it has to expand and cool below ambient
temperature.
It then heats up in the heat exchanger that is outside.

You then compress it which makes it hotter and push it through the internal
heat exchanger where it cools.

Then you expand it again, repeating as required.

Now it would be possible to take in fresh air, expand it to cool, heat it in
the heat exchanger and then compress it and release it in the inside
exchanger.
However it has problems, including..

no lubrication for instance unless you plan on throwing away the oil every
cycle.
condensation inside the expansion vessel as it cools.
noise caused by the release of the compressed air.
more difficult to control the flow rates so the air expands/compresses in
the right place.

I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas condenses, the latent heat absorbs most of the
energy.

In the OP the refrigerant was CO2. Does that condense?
There are a number of compressor types that don't need oil.

"Matty F" wrote in message
...

I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas condenses, the latent heat absorbs most of the
energy.

In the OP the refrigerant was CO2. Does that condense?

There is no need for it condense.
If you expand a gas it cools (Boyles law), it is then colder than the
outside air so will absorb heat from the outside.
Then you have to pump it into the inside and compress it, this heats it up
and it releases the heat it had absorbed.
If you don't expand it first you wont get much heat transfer.

It is somewhat easier to make a system work if it does condense as it is
easier to control the flow rates, all you need is a capillary tube.
There are a number of compressor types that don't need oil.

Matty F wrote:
On Jun 23, 3:36 am, harry wrote:
On Jun 22, 11:40 am, "dennis@home"
wrote:



"Matty F" wrote in message
...
On Jun 22, 8:37 pm, "dennis@home"
wrote:
"Matty F" wrote in message
Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.
It needs to be a closed cycle to pump heat from one side to the other.
It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.
No..
to collect heat from the outside it has to expand and cool below ambient
temperature.
It then heats up in the heat exchanger that is outside.
You then compress it which makes it hotter and push it through the internal
heat exchanger where it cools.
Then you expand it again, repeating as required.
Now it would be possible to take in fresh air, expand it to cool, heat it in
the heat exchanger and then compress it and release it in the inside
exchanger.
However it has problems, including..
no lubrication for instance unless you plan on throwing away the oil every
cycle.
condensation inside the expansion vessel as it cools.
noise caused by the release of the compressed air.
more difficult to control the flow rates so the air expands/compresses in
the right place.
I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas condenses, the latent heat absorbs most of the
energy.

In the OP the refrigerant was CO2. Does that condense?
There are a number of compressor types that don't need oil.
its a simple physics problem. There are three paths into and out of the
system.

air in at outside temp.
air out, colder than outside.
electricity in.

Total heat is electricity in + (specific heat of air times air flow rate
times temp difference between inlet and exhaust air). As long as that
difference is there, then some heat has been pumped from outside to inside.

How you do it, is only a matter of efficiency.

On Wed, 22 Jun 2011 22:06:36 +0100, dennis@home wrote:


There is no need for it condense.
If you expand a gas it cools (Boyles law), it is then colder than the


not Boyles law - that relates P and V noT involved lol
--
(º€¢.¸(¨*€¢.¸ ¸.€¢*¨)¸.€¢Âº)
.€¢Â°€¢. Nik .€¢Â°€¢.
(¸.€¢Âº(¸.€¢Â¨* *¨€¢.¸)º€¢.¸)

On Jun 23, 9:27 am, Tim Streater wrote:
In article
,
Matty F wrote:

On Jun 23, 3:36 am, harry wrote:
I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas condenses, the latent heat absorbs most of the
energy.

In the OP the refrigerant was CO2. Does that condense?
There are a number of compressor types that don't need oil.

Only with about 70 bar of pressure, if you want it to be liquid at 0C.

In that case CO2 would appear to be a much better choice for a
refrigerant than air. I'd better recycle the CO2 then.
Can't have that nasty CO2 escaping and causing Catastrophic Global
Warming can we

On Jun 22, 10:06*pm, "dennis@home"
wrote:
"Matty F" wrote in message

...

I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas *condenses, the latent heat absorbs most of the
energy.

In the OP the refrigerant was CO2. Does that condense?

There is no need for it condense.
If you expand a gas it cools (Boyles law), it is then colder than the
outside air so will absorb heat from the outside.
Then you have to pump it into the inside and compress it, this heats it up
and it releases the heat it had absorbed.
If you don't expand it first you wont get much heat transfer.

It is somewhat easier to make a system work if it does condense as it is
easier to control the flow rates, all you need is a capillary tube.



There are a number of compressor types that don't need oil.- Hide quoted text -

- Show quoted text -

In a refrigeration sytem, more energy is shifted than power consumed
by the compressor. I don't think thisis the case here. You only get
out what you put in.

On Jun 22, 10:09*pm, The Natural Philosopher
wrote:
Matty F wrote:
On Jun 23, 3:36 am, harry wrote:
On Jun 22, 11:40 am, "dennis@home"
wrote:

"Matty F" wrote in message
....
On Jun 22, 8:37 pm, "dennis@home"
wrote:
"Matty F" wrote in message
Seems to me that a DIYer could make a heat pump by just compressing
air inside and letting it expand outside.
It doesn't even have to recycle the air - just get some fresh air.
It needs to be a closed cycle to pump heat from one side to the other.
It needs to be a closed cycle only if you want to reuse the
refrigerant. If it's air at high prssure, just let it go outside and
get some more air.
No..
to collect heat from the outside it has to expand and cool below ambient
temperature.
It then heats up in the heat exchanger that is outside.
You then compress it which makes it hotter and push it through the internal
heat exchanger where it cools.
Then you expand it again, repeating as required.
Now it would be possible to take in fresh air, expand it to cool, heat it in
the heat exchanger and then compress it and release it in the inside
exchanger.
However it has problems, including..
no lubrication for instance unless you plan on throwing away the oil every
cycle.
condensation inside the expansion vessel as it cools.
noise caused by the release of the compressed air.
more difficult to control the flow rates so the air expands/compresses in
the right place.
I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas *condenses, the latent heat absorbs most of the
energy.

In the OP the refrigerant was CO2. Does that condense?
There are a number of compressor types that don't need oil.

its a simple physics problem. There are three paths into and out of the
system.

air in at outside temp.
air out, colder than outside.
electricity in.

Total heat is electricity in + (specific heat of air times air flow rate
times temp difference between inlet and exhaust air). As long as that
difference is there, then some heat has been pumped from outside to inside.

How you do it, is only a matter of efficiency.- Hide quoted text -

- Show quoted text -

More ********.
Never heard of Coefficient Of Performance then TurNiP?
http://en.wikipedia.org/wiki/Coefficient_of_performance

Theoretically a heat pump can shift an infinite amount of heat.

The practical limitations being the compression ratio of the
compressor and the boiling point of the refrigerant.

On Jun 22, 11:59*pm, Ghostrecon wrote:
On Wed, 22 Jun 2011 22:06:36 +0100, dennis@home wrote:
There is no need for it condense.
If you expand a gas it cools (Boyles law), it is then colder than the

not *Boyles law - that relates P and V noT involved lol *
--
*(º•.¸(¨*•.¸ * ¸.•*¨)¸.•º)
* * .•°•. *Nik .•°•.
*(¸.•º(¸.•¨* **¨•.¸)º•.¸)


He means Charles law.
Boyles and Charles laws are referred to as the combined gas laws.

On Jun 23, 12:13*am, Matty F wrote:
On Jun 23, 9:27 am, Tim Streater wrote:

In article
,
*Matty F wrote:

On Jun 23, 3:36 am, harry wrote:
I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas *condenses, the latent heat absorbs most of the
energy.

In the OP the refrigerant was CO2. Does that condense?
There are a number of compressor types that don't need oil.

Only with about 70 bar of pressure, if you want it to be liquid at 0C.

In that case CO2 would appear to be a much better choice for a
refrigerant than air. I'd better recycle the CO2 then.
Can't have that nasty CO2 escaping and causing Catastrophic Global
Warming can we

The advantage of using CO2 is that the heat pump perfoms better at low
temperatures.
http://en.wikipedia.org/wiki/Coefficient_of_performance

"Ghostrecon" wrote in message
...
On Wed, 22 Jun 2011 22:06:36 +0100, dennis@home wrote:


There is no need for it condense.
If you expand a gas it cools (Boyles law), it is then colder than the


not Boyles law - that relates P and V noT involved lol


So which one is PV/T = constant then?

"Matty F" wrote in message
...
On Jun 23, 9:27 am, Tim Streater wrote:
In article
,
Matty F wrote:

On Jun 23, 3:36 am, harry wrote:
I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas condenses, the latent heat absorbs most of the
energy.

In the OP the refrigerant was CO2. Does that condense?
There are a number of compressor types that don't need oil.

Only with about 70 bar of pressure, if you want it to be liquid at 0C.

In that case CO2 would appear to be a much better choice for a
refrigerant than air. I'd better recycle the CO2 then.
Can't have that nasty CO2 escaping and causing Catastrophic Global
Warming can we

Would that be natural CO2 or the nasty manmade stuff.
Then there is the in between stuff I have been making by burning that nasty
natural methane to make CO2 which is a much less powerful greenhouse gas.

Ghostrecon wrote:
On Wed, 22 Jun 2011 22:06:36 +0100, dennis@home wrote:


There is no need for it condense.
If you expand a gas it cools (Boyles law), it is then colder than the


not Boyles law - that relates P and V noT involved lol

Dont worry dennis' pretty little head over actual facts.

On Jun 23, 8:05*am, "dennis@home"
wrote:
"Ghostrecon" wrote in message

...

On Wed, 22 Jun 2011 22:06:36 +0100, dennis@home wrote:

There is no need for it condense.
If you expand a gas it cools (Boyles law), it is then colder than the

not *Boyles law - that relates P and V noT involved lol

So which one is PV/T = constant then?

Combined gas laws. Charles and Boyles laws.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Matty F
saying something like:

Seems to me that a DIYer could make a heat pump

By arranging a bank of fridge/freezer guts to do the job.

On Jun 23, 10:10*am, Tim Streater wrote:
In article
,
*Matty F wrote:





On Jun 23, 9:27 am, Tim Streater wrote:
In article
,
*Matty F wrote:

On Jun 23, 3:36 am, harry wrote:
I think in theory energy could be transferred.
However the big thing about refrigeration cycles is that on cooling
the refrigerant gas *condenses, the latent heat absorbs most of the
energy.

In the OP the refrigerant was CO2. Does that condense?
There are a number of compressor types that don't need oil.

Only with about 70 bar of pressure, if you want it to be liquid at 0C..

In that case CO2 would appear to be a much better choice for a
refrigerant than air. I'd better recycle the CO2 then.
Can't have that nasty CO2 escaping and causing Catastrophic Global
Warming can we

I doubt it. Above about 27C, CO2 is a gas whatever pressure you apply to
it.

--
Tim

"That excessive bail ought not to be required, nor excessive fines imposed,
nor cruel and unusual punishments inflicted" *-- *Bill of Rights 1689- Hide quoted text -

- Show quoted text -

Rubbish. Fire extinguishers.

On Jun 24, 12:21*am, Grimly Curmudgeon
wrote:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Matty F
saying something like:

Seems to me that a DIYer could make a heat pump

By arranging a bank of fridge/freezer guts to do the job.

The problem being evacuting and filling the system.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember harry saying
something like:

Seems to me that a DIYer could make a heat pump

By arranging a bank of fridge/freezer guts to do the job.

The problem being evacuting and filling the system.

Not a single system- several unmolested systems arranged in parallel.
I've observed that many fridge and/or freezer systems can be removed
from the cabinets in one piece and pressed to another use; either as an
air/air exchanger or even heating a water trough.