On 21 Feb 2005 12:12:59 -0800, wrote:


p j m@see _my _sig _for_address.com wrote:
On 21 Feb 2005 10:20:36 -0800, wrote:

Would you guys say that if a HP system is oversized, the COP can
fall
enough that the economic balance point is reached, even though the
reduction in capacity isn't enough to hit the thermal balance point?


Yep.

Well, if that's the case, then is the following true:

"below the 'thermal balance point', the heat
pump is STILL putting out economical heat into the house..."

?

%mod%

Oh, yes, absolutely.

The TBP is the point where the output of the heat pump is
sufficient to maintain target temps inside ( regardless of cost ).

The ECB is the point where the cost of getting a BTU out of
the HP exceeds the cost of getting it from some other source ( gas /
oil ).

In theory, the ECB of a HP CAN NOT fall below unity ** as
compared to electric strip heat **, IE, it will ALWAYS return at least
1 KW worth of heat for 1 KW of power to run it ( COP of 1 ).



Paul ( pjm @ pobox . com ) - remove spaces to email me
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