[Equest-users] eQuest Design Days

[Todd Lagus]

Thanks for your input Carol.

I think my main concern is that the sizing peaks aren't necessarily going to occur in the summer.  Say you have a building with a lot of south facing glass.  This space may peak in October.  I did a quick validation model in eQuest and another peak sizing program to see how different the loads would be for such a case.  The eQuest model solar gains were only about 35% of what the sizing program calculated.  I believe this is because the sizing program always assumes a clear day to size equipment for peaks, while the eQuest weather files use average data.  Each kind of calculation serves a purpose, one for sizing and one for simulation, but relying on the simulation weather file to size equipment seems risky.  Everything may turn out ok in these cases because the temperature is less in October than in the summer, but I'm not to a point where I'd trust it yet.  

Thanks,

Todd

 
Todd Lagus, EIT
Mechanical Engineer
Sebesta Blomberg
2381 Rosegate
Roseville, MN 55113
Phone: 651-634-7236
Fax: 651-634-7400
www.sebesta.com
 
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-----Original Message-----
From: Carol Gardner [mailto:gems at spiritone.com] 
Sent: Thursday, August 28, 2008 1:48 PM
To: Todd Lagus
Cc: equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] eQuest Design Days



Todd,

I have been told in the past that it is best to use the TMY weather file 
rather than the Design Day input. If you use the TMY3 file you should 
have all the latest weather/solar info. Just do as you would with DD 
calcs: revise you schedules for summer hottest day with everything on 
and winter coldest day dead of night with everything off, set your 
sizing factors to what you want and hit enter. This should give you good 
output. Be sure to have all the wall/glass info in that you want and be 
sure you have the right thermostat type and throttling range for it 
based on your HVAC system type.

Carol

Todd Lagus wrote:
>
> Hello All,
>
> Has anyone ever tried to use eQuest for sizing equipment? I know about 
> the design day input, but it only allows for a single design day, 
> which doesn't necessarily cover all of the bases for solar angles. 
> Based on the standard TMY2 weather files, I know that shouldn't be 
> done, but has anyone ever created some design day weather files? I'm 
> especially suspicious of the equipment sizing due to the sunlight 
> clarity factors. It would save a lot of time if eQuest could do design 
> day and simulation calculations that could be trusted, but I'm not 
> sure if there is a time effective way to do it. Any input would be 
> greatly appreciated.
>
> Thanks,
>
> Todd
>
> **Todd Lagus, EIT**
>
> Mechanical Engineer
>
> //Sebesta Blomberg//
>
> //2381 Rosegate//
>
> //Roseville////, MN 55113//
>
> //Phone: 651-634-7236//
>
> //Fax: 651-634-7400//
>
> //www.sebesta.com <http://www.sebesta.com>//
>
> //This message has been sent via the Internet. Internet communications 
> are not secure against interception or modification. Sebesta Blomberg 
> therefore cannot guarantee that this message has not been modified in 
> transit. This message and any files transmitted with it are 
> confidential and intended solely for the use of the addressee. If you 
> have received this message in error, please notify the sender and 
> destroy your copies of the message and any attached files.//
>
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>
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