View Single Post
Old 09-18-14, 01:26 PM   #25
mejunkhound
Apprentice EcoRenovator
 
Join Date: Apr 2011
Location: PNW
Posts: 197
Thanks: 0
Thanked 47 Times in 31 Posts
Default

Quote:
Originally Posted by charlesfl View Post
Dumb question.

Given the Carnot cycle limits how is the efficiency achieved with lower temperature difference for gshp?

Is it by lower compressor amperage used, shorter run times or something else?
Carnot is inversely involved with a heat pump cycle.

Look at it this way: it takes work to pump water uphill, in a like manner it takes work to move heat from low temperature to higher temperature.

Thus, lower temperature difference (as in GSHP from 55F earth to 100F air vs. 20F air to 100F air) means less work to pump heat to higher temperature, just like less work to pump a given quantity of water fewer feet uphill.
mejunkhound is offline   Reply With Quote
The Following User Says Thank You to mejunkhound For This Useful Post:
jeff5may (02-27-16)