[bldg-sim] Modeling buildings with natural ventilation for Appendix G

Mike Tillou miket at etcgrp.com
Thu Dec 28 09:56:13 PST 2006


There is no specific temperature range called out but Section G3.1.2.2
does limit the number of unmet heating and cooling hours your simulation
can have.  The heating and cooling schedules you establish would be the
required high / low temperatures you would need to meet.  
 
Again my interpretation of the Exception Calculation methodology is that
if I feel the design I am modeling doesn't need to meet G3.1.2.2 then I
need to argue the case why.
   
 

Michael Tillou, PE 
ETC Group, Inc - Energy Engineering for a Sustainable Future 
Ph:413-458-9870 

-----Original Message-----
From: bldg-sim at gard.com [mailto:bldg-sim at gard.com] On Behalf Of Jon
McHugh
Sent: Thursday, December 21, 2006 2:44 PM
To: bldg-sim at gard.com
Subject: [bldg-sim] Modeling buildings with natural ventilation for
Appendix G


Mike,
 
The prescribed range being what?  Is there a schedule of high and low
temperatures that are called out in Appendix G?
 
Thanks,
 
Jon

  _____  

From: Mike Tillou [mailto:miket at etcgrp.com] 
Sent: Thursday, December 21, 2006 11:12 AM
To: Jon McHugh; bldg-sim at gard.com
Subject: RE: [bldg-sim] Modeling buildings with natural ventilation for
Appendix G


I have always gone under the assumption that my results have to meet the
criteria for zone temperatures being within the prescribed range.
 
MMT
 

Michael Tillou, PE 
ETC Group, Inc - Energy Engineering for a Sustainable Future 
Ph:413-458-9870 

-----Original Message-----
From: Jon McHugh [mailto:Jon.McHugh at h-m-g.com] 
Sent: Tuesday, December 19, 2006 1:25 PM
To: Mike Tillou; bldg-sim at gard.com
Subject: RE: [bldg-sim] Modeling buildings with natural ventilation for
Appendix G


Mike,
 
Does this proposed methodology place limits on the number of occupied
hours above or below a given temperature/RH?
 
Thanks,
 
Jon McHugh

  _____  

From: bldg-sim at gard.com [mailto:bldg-sim at gard.com] On Behalf Of Mike
Tillou
Sent: Tuesday, December 19, 2006 7:18 AM
To: bldg-sim at gard.com
Subject: [bldg-sim] Modeling buildings with natural ventilation for
Appendix G


Ramana,
 
The ASHRAE 90.1 ECB sub-committee is working on a methodology for
simulating natural ventilation within the framework of Appendix G but I
don't think its finished yet.  In the meantime here is what I would
recommend.
 
Appendix G / 90.1 ECB allows you to use an exception calculation method
to simulate hybrid systems or unique efficiency measures to demonstrate
above-standard performance.  I think this would certainly apply in your
case.   
 
Here's what I have done on projects requiring an exception calculation
method.  
1. Establish your energy cost budget and your design energy case
following the Appendix G guidelines.  
2. Create a second model using the Design Energy Case as the baseline
and make the necessary modifications to simulate radiant heating / no
cooling via natural ventilation.  
3. Report the energy savings from your exception calculation as a line
item at the end of your LEED EA-1 summary table (similar to how
renewable energy is reported). 
4.  Include a seperate summary table  for the exception calculation
showing the energy end-use breakdown and how you arrived at the cost
savings.  Show both the baseline and proposed energy use.  
5. Make sure the savings are reasonable and prudent for the system you
are proposing.  
6. Document any changes to the model especially changes to schedules
that were necessary to properly simulate your system. 
7. Make it easy for someone to review your assumptions and the
methodology you used to estimate the savings
 
I hope this helps.  Good luck.
 
Mike
 

Michael Tillou, PE 
ETC Group, Inc - Energy Engineering for a Sustainable Future 
Ph:413-458-9870 

-----Original Message-----
From: bldg-sim at gard.com [mailto:bldg-sim at gard.com] On Behalf Of Ramana
Koti
Sent: Monday, December 18, 2006 4:53 PM
To: bldg-sim at gard.com
Subject: [bldg-sim] Modeling buildings with natural ventilation for
Appendix G


Dear all,

Is ignoring natural ventilation in both proposed and baseline designs an
accepted/fair way of modeling based on Appendix G (ASHRAE 90.1-2004)?

Part of the proposed design has (radiant heating + natural ventilation)
with no cooling which was modeled as a radiant slab, no cooling, natural
ventilation ignored. 

But the Baseline HVAC system based on Appendix G is System 5: Packaged
VAV w/Reheat. (Natural ventilation can be modeled based on Air Change
method or Sherman Grimsrud method though I do not know how to do it).

I cannot decide how to make the baseline and proposed comparable with
respect to Natural Ventilation (in a manner acceptable to LEED review),
suggestions will be appreciated.

Thanks,

Ramana Koti, Sustainable Building Analyst 
LEED AP

ELEMENTS | a division of berkebile nelson immenschuh mcdowell architects
106 W. 14th Street Suite 200
Kansas City, Missouri 64105

p 816.783.1635 f 816.783.1501
www.bnim.com| elements.bnim.com



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