[Equest-users] equest results for system sizing

[Pasha Korber-Gonzalez]

Hi Deepika,

The answers you are looking for are dependent on what you are trying to
achieve.   As Will had stated that it is not a great idea to use building
energy simulation programs as load calculation programs.  The reason for
this is two fold:
1)  Only use your tools for what they were designed for---you wouldn't cut
an apple with a chain saw, when a simple paring knife will do a much more
accurate and efficient job at slicing the apple.   With that example,
eQuest/DOE-2 are designed to estimate whole building energy consumption.
It can perform load calculations and analysis, however the energy models are
typically an "average" profile of energy use throughout a one year period.
The program doesn't properly size HVAC equipment for the peak heating or
cooling days, as it is not always likely that the weatehr file you are using
will represent these peak design days that HVAC designers are held too for
life-safety purposes.

2)  With so many potential variable unknowns if you are not an experience
eQuest/DOE2.2 user there is much opportunity for risk in your design
calculations.  As Will pointed out, it is stated very clearly on the
building loads reports that these "design load" calcs do not include the
impact of ventilation air requirements.  The closest place you can extract
this number is from the SV-A reports for each of the HVAC systems you have
in your model.

Are you in the process of designing your building using eQuest, or are you
using eQuest to evaluate your HVAC design?  Dependent on your answer will
guide how you use eQuest/DOE2.2 to accomplish your task at hand.

If you are performing your building design load calculations, I also highly
recommend that you do not use any whole building energy sim program for that
purpose.  Choose another load program (i.e Trace or HAP) and then once you
have a completed set of design load calcs then it would be good practice to
building your whole building energy model and compare the calculated
simulation results with your official design load calcs to find where some
of the detail might have been lost.

I've attached a DOE-2.2 document from the eQuest developers that can be used
as a navigational reference for the DOE-2 output reports and what types of
information and variables can be referenced in each report.  The SV-A report
is an output for each AHU (HVAC air system) that you have in your model.
>From this report you can find the overall Supply air flow (CFM), and htg &
clg capacities.   To find the equipment capacities for your plant equipment
you will need to reference the "P" reports in your sim file.

Cheers,
Pasha

On Mon, Sep 19, 2011 at 8:31 AM, Deepika <deepika.khowal at gmail.com> wrote:

>  Thanks for the inputs. .
> So typically use the kw numbers from Equest and use it in trace ?
> Do you also add a sizing factor ?
>
>
>
> On Sep 19, 2011, at 6:49 AM, PKConsulting <pasha.pkconsulting at gmail.com>
> wrote:
>
>   Deepika
> Use the sv-a reports for ahu sizing.
>
> Pashalu
>
> On Sep 19, 2011, at 6:33 AM, "Will Mak" <wmak at epsteinglobal.com> wrote:
>
>   Honestly, I don’t like using eQuest for load calcs. I typically use
> Trane Trace or HAP…****
>
> ** **
>
> Especially since the load summary states in big letters that ventilation is
> not accounted for in the calcs. You could do them separately but still…***
> *
>
> ** **
>
> Just my 2 cents.****
>
> ** **
>
> *William Mak, LEED AP BD+C*
> Mechanical Design Engineer
>
> *EPSTEIN*
> 600 West Fulton Street
> Chicago, Illinois 60661-1259
> D: (312) 429-8116
>
> ****
>
> ** **
>
> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *deepika khowal
> *Sent:* Sunday, September 18, 2011 5:33 PM
> *To:* <equest-users at lists.onebuilding.org>
> equest-users at lists.onebuilding.org
> *Subject:* [Equest-users] equest results for system sizing****
>
> ** **
>
> Hi all****
>
> I would like to know to get an idea for system sizing based on modeling in
> equest.****
>
> where in equest do everyone look for sizing Numbers?****
>
> I have always been looking at design sizing tons from air side HVAC tab.
> But I realized they are very different from detailed report sizing.****
>
> If anyone can direct me through this, it will be helpful.****
>
>  ****
>
> 1.       Using air-side HVAC summary : design sizing tons****
>
> <image001.jpg>****
>
>  ****
>
> 2.       Using building peak components, taking the kbtu/hsf number and
> diving by 12000 to get cooling tons. This number is very low compared to
> design capacity.****
>
> <image002.jpg>****
>
>  ****
>
> 3.       Using PS-C report****
>
> <image003.jpg>****
>
>  ****
>
> Is there any other report which mechanical designers use to size system?**
> **
>
> Thanks****
>
>  Deepika****
>
>  ****
>
> ** **
>
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