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

[Simge Andolsun]

or simply eQUEST might be calculating more than zero loads during these
night hours whereas EnergyPlus calculates zero load...


On Thu, Feb 13, 2014 at 3:50 PM, Simge Andolsun <simgeandolsun at gmail.com>wrote:

> 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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