[Equest-users] eQUEST vs EnergyPlus: Fan Energy Consumption

[Simge Andolsun]

Joe hi!

I tried that one. Nothing changed in fan energy consumption between cycling
and continuous. I feel like eQUEST has a default fan control for PTAC
(which is continuous) and uses it no matter what.


Thanks,
Best Regards,
Simge Andolsun, Ph.D.


On Thu, Feb 13, 2014 at 3:27 PM, Joe Huang <yjhuang at whiteboxtechnologies.com
> wrote:

>  Simge,
>
> You might want to try (in eQUEST/DOE-2)  FAN-CONTROL = CYCLING instead of
> FAN-CONTROL = CONSTANT-VOLUME
>
> Joe
>
> Joe Huang
> White Box Technologies, Inc.
> 346 Rheem Blvd., Suite 108D
> Moraga CA 94556yjhuang at whiteboxtechnologies.comhttp://weather.whiteboxtechnologies.com for simulation-ready weather data
> (o) (925)388-0265
> (c) (510)928-2683
> "building energy simulations at your fingertips"
>
>
> On 2/13/2014 1:15 PM, Simge Andolsun wrote:
>
>  Joe hi!
>
> Thanks for your response. I had autosized the systems in both programs.
> Since the loads were different, then the air flow rates ended up being
> different. Based on your comments, I entered the air flow rate calculated
> by eQUEST into EnergyPlus. I also added the Daylight saving time of eQUEST
> into EnergyPlus. Attached is how my charts currently look like. I am also
> attaching the new EnergyPlus file. Most of the problems seem to have been
> resolved except the night time control. I would appreciate any suggestion
> on solving this discrepancy between the two models.
>
> Thank you very much in advance,
> Best Regards,
> Simge Andolsun, Ph.D.
>
>
> On Thu, Feb 13, 2014 at 1:40 PM, Joe Huang <
> yjhuang at whiteboxtechnologies.com> wrote:
>
>>  (repost of comment on EnergyPlus_Support bulletin board in case any
>> eQUEST-Users readers have other thoughts or corrections)
>>
>> -------- Original Message --------
>> Subject:     Re: [EnergyPlus_Support] eQUEST vs EnergyPlus: Fan Energy
>> Consumption
>> Date:     Thu, 13 Feb 2014 11:32:17 -0800
>> From:     Joe Huang <YJHuang at whiteboxtechnologies.com><YJHuang at whiteboxtechnologies.com>
>> Reply-To:     EnergyPlus_Support at yahoogroups.com
>> To:     EnergyPlus_Support at yahoogroups.com
>>
>> Simge,
>>
>> Looking at your plots, it seems that the eQUEST fan is simply larger by
>> 40% or so.  Are you letting the programs autosize the equipment, and did
>> you use any sizing-factors  or sizing-ratios in the runs?  I would just
>> take the larger
>> capacity of the two runs, and use that for both runs, which should take
>> care of the discrepancy.
>>
>> Other observations:
>> 1. eQUEST CYCLE-ON-ANY seems to keep the fans on the entire hour, whereas
>> EnergyPlus seems to cycling them on
>>     only when the HVAC is on.
>>
>> 2. You seem to have daylight savings in the eQUEST, but not in the
>> EnergyPlus model.
>>
>> Joe
>>
>>
>> Joe Huang
>> White Box Technologies, Inc.
>> 346 Rheem Blvd., Suite 108D
>> Moraga CA 94556yjhuang at whiteboxtechnologies.comhttp://weather.whiteboxtechnologies.com for simulation-ready weather data
>> (o) (925)388-0265
>> (c) (510)928-2683
>> "building energy simulations at your fingertips"
>>
>>
>> On 2/13/2014 9:06 AM, Simge Andolsun wrote:
>>
>>   Dear EnergyPlus users,
>>
>> We have modeled a test case with exactly same inputs in eQUEST and
>> EnergyPlus to compare the results of these programs for an identical
>> situation. This case had a PTAC system with electric heating. The fan
>> inputs were as follows in both eQUEST and EnergyPlus:
>>
>> ·         0.3 inWG (74.7 Pa), 0.6 total efficiency fraction
>>
>> ·       In eQUEST: Fan control is constant volume, with night time
>> cycling
>> In EnergyPlus: Fan control is constant volume (fan control
>> schedule=1) when the fans are scheduled to be on and it is cycling (fan
>> control schedule=0) when the fans are scheduled to be off. I used
>> AvailabilityManager:NightCycle to set this control (Please let me know
>> whether there is any better way to model the same fan control condition in
>> eQUEST and EnergyPlus).
>>
>> ·         California Title 24 fan availability schedules were used in
>> both programs. These schedules turn the fan off during the hours listed
>> below:
>>
>> Weekdays: Between 8pm-5am
>>
>> Saturday: Between 3pm-5am
>>
>> Sundays and Holidays: Off all day.
>>
>> The fan energy consumption of the two programs ended up differing from
>> each other significantly. Attached are the charts that show the results of
>> the coldest and warmest days. Would you let me know what might be the
>> reason for this difference between the two programs?
>>
>> Thank you very much in advance for your help,
>> Best Regards,
>> S. Andolsun, Ph.D.
>>
>>
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>
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