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.