[Bldg-sim] ASHRAE 90.1 Appendix G3.1.2.2

[milda margarin]

hi Varun thanks for your reply! I have another question though based on your statement that the system should be based on the 'design results'; I thought the whole point of using simulations is to predict the peak capacity required and then base your design on this? (possibly by applying safety factors according to real life experience).And how can you have unmet loads when you design based on the peak load? In that case the 'peak load' is not the maximum load?Further comments anybody? best regardsMilda
From: seldomvarun at gmail.com
Date: Tue, 29 Mar 2011 07:51:29 -0400
Subject: Re: [Bldg-sim] ASHRAE 90.1 Appendix G3.1.2.2
To: empire999 at hotmail.com

Milda,
I think if you are performorming energy simulations for the baseline, it doesnt matter what is this 25% and 15% upsizing is used for, as it used only as much capacity it needs. And your system size should be based on the design results and not simulation results (that also proposed model).


But nevertheless I always interpret this as you said in your first point, to cover uncertainity in building simulation. 
I also think it helps baseline to reduce its unmet load hours.
 
I hope this helps.


On Tue, Mar 29, 2011 at 3:27 AM, milda margarin <empire999 at hotmail.com> wrote:


hi , I already submitted this question but there were no responses so I'd like to try again: 
 could somebody share some insight to the ASHRAE 90.1 Appendix G3.1.2.2 point regarding heating and cooling equipment sizing based on building energy simulations. It is stated that the equipment should be oversized by a factor of 1.25 for heating and 1.15 for cooling. Are these "safety factors" based on the uncertainty associated with building energy simulations or a requirement that makes sure that the system can respond quickly enough during startup? Why are there different factors applied for heating and cooling?


thanks!
Milda


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-- 

Thanks and Best Regards,
 
Sincerely,
Varun Kulkarni , M.S. , EIT
RMF Engineering
5520, Research Park Drive, Suite 300
Baltimore, MD - 21228
 
Office : 410-576-0505 ext. 5352
Mobile: (+1)405-385-1928
 
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