PTAC Curve

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Hi Everybody,

Does anyone understand the heating EIR curves used for PTACS in Equest? It
is the "DX-Heat-EIR-fEDB&OAT" curve. I calculated the curve using excel
(see attached spreadsheet) and found as the outside air gets colder the
efficiency of the heating curve increases. Does that make sense to anyone?

Thanks in advance,


Lee Chorney's picture
Joined: 2012-06-21
Reputation: 0

The EIR modefier curve acts as a multiplier on the COOLING-EIR value,
which is the the reciprocal of the COP. Therefore, if you multiply the
your curve values times the COOLING-EIR and take the inverse, you will
see that the efficiency is actually decreasing, approaching COP=1.0 at
low temperatures. Keep in mind that this curve is not the only EIR
modifier curve, there is also the PLR curve...


David Reddy3's picture
Joined: 2011-09-30
Reputation: 0