[Bldg-sim] LEED Comments for EAC1 - Optimize Energy Performance

[James Hansen]

Appeasing the GBCI reviewers is always about proper documentation.  They shouldn't have to go thru every zone/system in your .inp file to make sure there is a corresponding system.  Hell, it's hard enough for us to do that (without being able to open up eQuest).

 

Comment #1:  Plain and simply state:  The baseline building has been configured so that each thermal zone has a corresponding system, and the thermal zones for the baseline building match the proposed building.  (and you just need to make sure this is the case - if you have an unconditioned zone attached to a system, you might want to say that the unconditioned zone has no impact on the system, but eQuest requires each zone to have an associated system and thus you have to have it share a system with a conditioned zone).

 

Comment #2:  Like Chris said, make a spreadsheet, and use it for every project.  The small amount of time it takes to program excel to determine if the CFM is > or < than 20,000 CFM and automatically use the correct formula will pay for itself quickly.

 

Comment #3:  Plain and simply state:  eQuest's autosize routine is based on the 20 degree delta T that we have entered for each system (show a screenshot of that eQuest tab to help back this up, and circle in red).  Therefore, although it is autosized, the CFM is correctly configured based on this 20 degree delta T, and thus specific entry of CFM quantities in the system tabs is not required.

 

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From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Chris Jones
Sent: Thursday, April 01, 2010 12:28 PM
To: bldg-sim at lists.onebuilding.org
Subject: Re: [Bldg-sim] LEED Comments for EAC1 - Optimize Energy Performance

 

The first comment seems like the reviewer isn't carefully reviewing the submission.  It is fairly simple to check the proposed sim file and the Budget case sim file to see if each zone in the proposed case is modelled as a single zone system in the Budget case.  I have seen this comment before and I am not sure what additional documentation the review might want to make it "clearer".

Comment 2: I always setup a spreadsheet showing my calculation of total fan power for the proposed case and the Budget case.  

Comment 3: The 20°F differential is the difference between the room set point and the supply air temperature.  Re Autosizing supply air flows: I always autosize the Baseline air flows based on the 20°F supply air to room air temperature difference (G3.1.2.8).  I set the heat sizing ratio to 1.25 and the cool sizing ratio to 1.15 as per G3.1.2.2.  Never had a problem with this approach.  I suppose you could do a sizing run with those sizing ratios then explicitly enter the resulting supply air flows, heating and cooling capacities but it would amount to almost the same results.  

At 02:56 AM 4/1/2010, Ashraf Khan wrote:

Hello,
 
I received some comments from USGBC regarding my project initial review, in Credit EAC1 - Optimize Energy Performance. Please advise me how I can solve below mentioned comments in the review submission,
  

1.	It is unclear whether one Baseline Constant Volume system was modeled per thermal zone in the Baseline Case as required. Please verify that one system was modeled per zone, and that the Baseline System efficiency for each zone was modeled consistently with the capacity for the Baseline System serving that zone. (please guide me how to solve this comment) 

  

1.	Section G3.1.2.9 describes calculation used to determine the fan power in the baseline building. Please list the total fan volume, capacities, and fan power for the Baseline and Proposed system. (As my system doesn't have any Return fan, so i am dividing the ASHRAE total Fan power by 70% supply, 20% return, 10% exhaust based on my understanding. Please guide me if any changes required) 

  

1.	Based on supporting document, supply fan volumes of some of the zones in the baseline design appear to be modeled as "AUTOSIZED". For the baseline design the fan supply volumes should be calculated based on the system capacity and a temperature differential of 20°F, as set forth in Section G3.1.2.8.(Please guide me Where can we enter the temperature diff, is in Cooling Coil or any other ways.) 

 
Thanks & Regards,
Khan
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Chris Jones
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