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5.7.6 AFUE and HSPF conversions #232

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
What NACM Section(s) are relevant to this issue?
5.7.6.4 Furnace Fuel Heating Efficiency
5.7.6.5 Electric Heat Pump Heating efficiency 

Explanation of issue:
The AHUE and HSPF conversions are dependent on whether the system is a 
SinglePackage or Split system type. Based on my brief research, the efficiency 
requirements of HVAC equipment is now the same regardless if the system type is 
Split or Packaged.  There is currently no property in the SDD that is used to 
distinguish between split or packaged.  I can add one, but it appears that 
these are the only two ACM descriptors that are dependent on this definition, 
and if the appliance efficiency requirements are now the same, I wonder if 
these separate equations are still relevant.

Proposed resolution:
Revise the ACM to remove dependence of conversions on split vs packaged.  It is 
not difficult to add the necessary SDD property, but this is one more piece of 
information that the user has to define though it no longer seems that relevant 
(it would only be used in the ruleset for these conversions).  If the 
performance of modern split/packaged equipment really is that different, than 
it is fine to leave as is and I will add the property.

Please provide any additional information below.

Original issue reported on code.google.com by da...@360-analytics.com on 24 May 2013 at 3:35

GoogleCodeExporter commented 9 years ago 
Resolution:

Use "Single Package" conversion curve in all cases. This curve is more 
conservative (lower thermal eff prediction) than the split system curve for 
high AFUE. For moderate (75-85) AFUE curves are nearly the same. See 
attachment.  Note: I don't know the source of the current curves, and don't 
have the time to develope new ones.

Original comment by JohnJArent on 28 May 2013 at 9:53

Attachments:

GoogleCodeExporter commented 9 years ago 
Works for me.  Will the HSPF to COP conversion also be reduced to only use the 
"Single Package" curve as well.

Original comment by da...@360-analytics.com on 28 May 2013 at 11:22

GoogleCodeExporter commented 9 years ago 
John,
Still see separate curves for single package and split heat pumps (5.7.6.5).  
Can you confirm that only the Single Package curve will be used for all systems 
as well?

Original comment by da...@360-analytics.com on 24 Sep 2013 at 9:54

GoogleCodeExporter commented 9 years ago 
Making this change for the upcoming release v3.0.  I am removing the separate 
conversion equation for split system heat pumps from HSPF to COP, to simplify 
the ACM.

Original comment by JohnJArent on 19 Nov 2013 at 9:46

GoogleCodeExporter commented 9 years ago 
See attached file with changes

Original comment by JohnJArent on 22 Nov 2013 at 12:00

Attachments: