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CBECC-Com Issue #931

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago 
CBECC-Com Version 3a (687)

Other Issue – ExistingAlteration baseline model

Set Roger as Owner

I was experimenting with CBECC-Com in trying to model an existing building and 
then to make only one change with something to see the difference in energy 
based on that change.  So I took the ‘020012S-OffSml-CECStd’ template and 
set everything I could find to ‘Existing’.  And I set the ComplianceType to 
ExistingAlteration.  Then I ran it and the result (compliance margin) wasn’t 
zero, which I think it should be if everything is existing.  The margin appears 
to be coming from the cooling and I think I narrowed it down to the SEER rating 
of the cooling equipment.  Even though it’s set as EXISTING, the baseline 
model appears to be assuming a SEER of 9.7 instead of matching the proposed 
efficiency.

Original issue reported on code.google.com by f.le...@gmail.com on 7 Feb 2015 at 12:20

GoogleCodeExporter commented 9 years ago

Original comment by rhedr...@archenergy.com on 7 Feb 2015 at 12:45

GoogleCodeExporter commented 9 years ago 
I reviewed and indeed it is a bug in the rule logic for the property 
CoilClg:DXEER. The problem was the rule was not looking at the status/value of 
the user's input, but rather the status/value of the property in the local 
"transform".

The net result is the baseline cooling efficiency is UNDEFINED when sent to 
OpenStudio for simulation. In this case, OpenStudio assumes a default gross 
cooling efficiency of COP-3.0, which roughly translates to the net efficiency 
of SEER-9.7, as you found in your testing. 

This bug is limited to Existing* compliance models that have existing, 
SEER-rated DX systems. 

A fix has been committed @ r3028

Original comment by da...@360-analytics.com on 7 Feb 2015 at 12:48