thermal dynamics ?

Thread Starter

Mathematics!

Joined Jul 21, 2008
1,036
ok, but then why does a refrigerator need electrical supply.
I.e where in the compressor is electricity needed (if it is just a spring valve then it would be just by mechanical methods)
So if their wasn't a need for fans , ice maker , lighting why would the compressor need an electrical supply?

What I am getting at is if you just had a compressor , and coils with no electricity in theory you should be able to make a primitive cooling system/heating system.

Also
Anybody know anything about how to calculate the best refrigerant , and how to calculate the change in temperature given off by a formula?
 

#12

Joined Nov 30, 2010
18,224
The word that made it all click for me was, "enthalpy". Pressure/enthalpy charts are published for each refrigerant and can be found on the internet.

Which is the best refrigerant? Depends on what you are trying to do. Different pressures and enthalpies for different jobs. One limitation of compressors is that they don't suck very well on a pressure of 5 or 10 psia. You choose a refrigerant to have the right temperature on the low pressure side when it has enough pressure to feed a significant mass into the compressor intake.

Just a partial answer while I'm taking a break from a plumbing job.
 

Kermit2

Joined Feb 5, 2010
4,162
What I am getting at is if you just had a compressor , and coils with no electricity in theory you should be able to make a primitive cooling system/heating system.
Yes, you could do it without electricity. Some place in your scheme though, WORK will have to be done.

I connected my air pump to my bike tire, but nothing happened?
Oh yeah, I have to PUMP it to compress air into the tire.

I wish I had an electric motor to do the pumping for me. :)
 

Wendy

Joined Mar 24, 2008
23,415
The good news is there are hints that Peltier Coolers are going to get a lot more efficient in the not so far future. We could really use them.
 
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