"Astro" wrote in message
newspsk6ly6w3v1dc2q@athlon2600...

On Tue, 25 Jan 2005 17:31:23 -0500, geoman wrote:
snipped long message out


Astro, ignore the TempRise for efficiency on your Geothermal unit, it has
nothing to do with it by itself, it is only PART of the equation and
numbers
we use to indicate what a geothermal unit or heat pump is doing. One must
have ARI numbers in order to do these calculations and then do
temperature
checks along with voltage and amperage readings. Heat Pumps and
Geothermals
makes HVAC a real science that can be proved instead of using a wet
finger
in the air test.

Rich,
of course, I agree, delta T is only one number in the equation. The big
concern with my system this winter has been absolute BTU output and the
sustainability of that output.
As for efficiency, I have clamp-metered the compressor amperage and air
handler current a couple times to get an estimate of COP for my unit. I
need to remeasure now that it's been running continuously during the cold
weather, pushing out about 30k BTU. At last measure, the system was
running about 2.8 COP pushing 36k BTU. Nothing to brag about...

My crack about the 5 ton conventional HP is because even in these cold air
temp days, a 5 ton air source HP would be cranking out more BTU's (based
on the published curves) than my less-than-optimal 4-ton geothermal
system. As noted, partly tongue in cheek because the real solution is to
get my installation repaired so that it's pumping from a reasonable ground
temp at which point no air source system should be able to touch it.

I'm curious to which system / brand do you have? What model and what type of
loop?