[Equest-users] DHW loads difference

[David Reddy]

Pramod,
I'd also suggest confirming that the keyword CIRCULATION-LOOP:PROCESS-T 
is the same in both your models.  This property is not exposed in the 
UI, but is likely in your input file, and I believe the wizard sets it 
by default to be the same as the CIRCULATION-LOOP:DESIGN-HEAT-T. If the 
PROCESS-T is less than DESIGN-HEAT-T, which can happen if you set the 
loop temps in the wizard and then change them in the detailed interface, 
this will impact your results.

On 1/12/2015 5:55 AM, Nathan Miller wrote:
>
> My guess is that it is the standby losses making the difference. You 
> presumably have the tanks assigned to a zone. If there is a difference 
> in envelope, lighting loads, plug loads, etc in that zone between the 
> two runs, then it might affect the standby losses (because the delta-T 
> in the space could be different). If you want to test that theory, 
> assign the DHW heater to be “Outdoor” in both runs, that way standby 
> losses should be identical. If the energy use aligns, you will know it 
> was standby loss making the difference. If they are still different, 
> it is something else (schedule, peak gpm, DHWH efficiency, etc).
>
> **
>
> *Nathan Miller, PE, LEED AP BD+C**– */Mechanical Engineer/Senior 
> Energy Analyst/**
>
> *RUSHING*| *D*206-788-4577 |*O*206-285-7100
>
> *www.rushingco.com <http://www.rushingco.com/>***
>
> *From:* Equest-users 
> [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of 
> *Pramod .D
> *Sent:* Monday, January 12, 2015 8:42 AM
> *To:* Byron Burns; equest-users at lists.onebuilding.org
> *Subject:* Re: [Equest-users] DHW loads difference
>
> Byron,
>
> Thanks for your immediate reply. I have compared all the schedules, 
> volume, capacity, tanks loss, etc. Everything is same but I am getting 
> difference in results. Please help me out on this and thanks for the 
> manual.
>
> Thanks,
>
> **
>
> *Pramod D*| *Junior Energy Analyst*
>
> *d.pramod at setty.com <mailto:d.pramod at setty.com>*
>
> *From:*Byron Burns [mailto:B.Burns at ha-inc.com]
> *Sent:* Monday, January 12, 2015 7:04 PM
> *To:* Pramod .D; equest-users at lists.onebuilding.org 
> <mailto:equest-users at lists.onebuilding.org>
> *Subject:* RE: DHW loads difference
>
> Hello Pramod,
>
> You should be able to get the results to line up, if you are 
> interested in the algorithm used,here 
> <http://doe2.com/download/DOE-21E/DOE-2EngineersManualVersion2.1A.pdf> 
> is a link to the engineering manual.  Generally, the DHW energy is 
> modeled just like a process load with a few more knobs (hourly demand 
> * fractional schedule)/DHW efficiency + standby loss.  There is a 
> portion of the calculation that accounts for the tank loss, which is a 
> factor of the size of the tank, the amount of insulation on the tank 
> and the ambient conditions, so make sure both the baseline and 
> proposed models have the same volume, amount of insulation and are 
> located in the same zone.
>
> To ensure it is not something simple, I would recommend re-inputting 
> the data and running it again.  You will notice that eQ rounds many of 
> the inputs in the GUI, however it will input the actual values into 
> the .inp file and .bld file when you run it, so make sure all inputs 
> are the same regardless of how they are displayed.  Also the schedules 
> are a common cause of these issues.  I recommend using something to 
> compare the inputs of both your baseline and proposed .inp files to 
> ensure they are the same.  Personally, I like Notepad++, 
> <http://notepad-plus-plus.org/> it has a compare plug in that makes it 
> a snap.
>
> Hope that helps,
>
>
> *Byron D. Burns, EIT, BEMP*
> Energy Engineer, Building Sciences Studio
>
> *H&A | Hankins & Anderson* | www.ha-inc.com <http://www.ha-inc.com>
> *d:* (804) 420-1622 *p:* (804) 285-4171 *f:* (804) 217-8520
>
> *From:*Equest-users 
> [mailto:equest-users-bounces at lists.onebuilding.org] *On Behalf Of 
> *Pramod .D
> *Sent:* Monday, January 12, 2015 7:51 AM
> *To:* equest-users at lists.onebuilding.org 
> <mailto:equest-users at lists.onebuilding.org>
> *Subject:* [Equest-users] DHW loads difference
>
> Hi,
>
> I have modelled an apartment using eQuest. I have given the same 
> inputs (capacities, schedules,etc) in both the models for *DHW* but I 
> am getting difference in the results. Can anyone please tell how 
> eQuest calculates DHW loads. Why I am getting difference in DHW loads. 
> The images are attached.
>
> Thanks,
>
> Pramod
>
>
>
>
>
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