[Equest-users] Variation in incident solar radiation on east and west surface of a building in different simulation tool

[Joe Huang]

I've been corresponding with Mayank offline and have determined that the cause for the 
difference is due entirely to the 30 minute difference between the GMT 5.50 time zone for 
India, and the GMT 5.0  integer time zone input into eQUEST.

I'm summarizing the e-mail exchange with Mayank below for those who may be curious as to 
the cause and solution for this discrepancy in solar radiation on different orientations.

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"

On 9/26/2014 6:23 AM, Mayank Bhatnagar wrote:

Dear Joe,

Thanks for your response.

We took your recommendations and have been able to resolve the problems. Results for east 
and west facade are consistent for Eplus and eQuest post the longitude correction.I have 
attached these files for your reference as well.



Regards,
Mayank

On Fri, Sep 26, 2014 at 7:14 AM, Joe Huang <yjhuang at whiteboxtechnologies.com 
<mailto:yjhuang at whiteboxtechnologies.com>> wrote:

Mayank,

I suspect that this discrepancy in the peaks is an artifact of the eQUEST/DOE-2 limitation 
of accepting only integer time-zones.
One way to adjust for this is to move the longitude of the building site by 7.5 degrees, 
i.e., if you input the time zone as 5, then  subtract 7.5 degrees from the building 
location, and if you input the time zone as 6, then add 7.5 degrees to the building location.

I was going to experiment with that, but then thought it would save some of my time if you 
could send me your eQUEST (*.inp) and EnergyPlus (*.idf) input files.  That would also 
clarify to me which variables you're pulling out as the solar radiation terms.

Thanks.

Joe

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com  <mailto:yjhuang at whiteboxtechnologies.com>
http://weather.whiteboxtechnologies.com  for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"


On 11:59 AM, Mayank Bhatnagar wrote:
Dear Joe,

I am using the same weather file for both energy plus and eQuest. As eQuest uses BIN 
format I converted the same epw format file using eQ_wthProc tool (EPW to BIN converter). 
I have attached a spreadsheet (New Delhi_ISHRAE_2014EPW.xlsx)  that compares Total global 
Horizontal radiation and direct normal radiation for EPW file (by converting it into CSV 
format) and eQuest hourly outputs (as it reads BIN file). Since both the global horizontal 
and direct normal radiations are identical, conversion from epw to bin seems correct. 
Additionally, as you know, eQuest doesn't take diffused radiation from the weather file, 
it calculates itself.

Since I am using the same source file for both eQuest and Eplus simulations I would expect 
similar trend in solar radiation data for both East and West facades. However, for Delhi I 
found variation in solar radiation output for east and west facade. I have attached 
results spreadsheet (eQUest and energy plus_Miami and Delhi_v1.xlsx) for your reference.

Interestingly, when I performed a similar analysis for "Miami epw and bin file", I got 
fairly consistent results (refer graph below, the results are for June 6 to June 9)

  (plots deleted)

On 9/24/2014 8:18 AM, Jeff Haberl wrote:
>
> FYI:
>
> You also didn't say that you're using the EPW weather file in EQUEST, only that EQUEST 
> is using .BIN format (or binary). Is EQUEST using TMY2 or TMY3?
>
> Jeff
>
> 8=!  8=)  :=)  8=)  ;=)  8=)  8=(  8=)  8=()  8=)  8=|  8=)  :=')  8=) 8=?
> Jeff S. Haberl, Ph.D.,P.E.inactive,FASHRAE,FIBPSA,......jhaberl at tamu.edu 
> <mailto:........jhaberl at tamu.edu>
> Professor........................................................................Office 
> Ph: 979-845-6507
> Department of Architecture............................................Lab Ph:979-845-6065
> Energy Systems Laboratory...........................................FAX: 979-862-2457
> Texas A&M University...................................................77843-3581
> College Station, Texas, USA, 77843..............................URL:www.esl.tamu.edu
> 8=/  8=)  :=)  8=)  ;=)  8=)  8=()  8=)  :=)  8=)  8=!  8=)  8=? 8=) 8=0
> ------------------------------------------------------------------------------------------
> *From:* Bldg-sim [bldg-sim-bounces at lists.onebuilding.org] on behalf of Peter Simmonds 
> [psimmonds11 at gmail.com]
> *Sent:* Wednesday, September 24, 2014 10:15 AM
> *To:* Mayank Bhatnagar
> *Cc:* bldg-sim at lists.onebuilding.org
> *Subject:* Re: [Bldg-sim] Fwd: Variation in incident solar radiation on east and west 
> surface of a building in different simulation tool
>
> Try checking the date and time set on the programs. One could be using summertime hours ?
>
> Peter Simmonds, Ph.D., ASHRAE Fellow and DL
> Mobile US: +1-310-383-9911
> Mobile HKG: +852-9845-4902
> Mobile UK: +44 7711 926317
>
> On Sep 24, 2014, at 8:06 AM, Mayank Bhatnagar <mayank.23aug at gmail.com 
> <mailto:mayank.23aug at gmail.com>> wrote:
>
>> Dear Dru,
>>
>> Yes, I am using the same weather file for all simulation tools. eQuest used bin format, 
>> which I have already checked with weather file (epw format). The bin file only have 
>> total horizontal radiation and Normal direct radiation, the diffuse radiation is being 
>> calculated by eQuest itself (as per Joe huang's mail: previously asked for a query on 
>> eQuest users). TRNSYS and E+ used epw format.
>>
>> The variation are found in radiation falling on east and west surface of the building.
>>
>> Regards,
>> Mayank
>>
>> On Wed, Sep 24, 2014 at 8:23 PM, Dru Crawley <dbcrawley at gmail.com 
>> <mailto:dbcrawley at gmail.com>> wrote:
>>
>>     Are you using the same hourly weather data in eQuest, TRNSYS and EnergyPlus?  The
>>     radiation can vary significantly.
>>
>>     On Wed, Sep 24, 2014 at 7:42 AM, Mayank Bhatnagar <mayank.23aug at gmail.com
>>     <mailto:mayank.23aug at gmail.com>> wrote:
>>
>>
>>         Dear All,
>>
>>         I am doing envelope analysis of a rectangular building in eQuest. The building
>>         have identical parameters for all perimeter zones. The simulation is being done
>>         for New Delhi climate zone. The results shows that the total solar heat gain
>>         through glazing is more in east zone compare to west zone. In the result of
>>         that the total load and energy consumption in east zone is higher than in west
>>         zone.
>>
>>         To verify the results, I analyzed the total horizontal and beam radiation
>>         incident on east and west facade. Here, the issue was started. In the eQuest,
>>         there always high incident solar radiation in east surface compare to west
>>         surface. However, the incident solar radiation on east and west surface in
>>         energy plus and TRNSYS have different trend from the eQuest. Here I am
>>         attaching graph showing variation of incident solar radiation in east and west
>>         facade with energy plus and TRNSYS.
>>
>>         Any guidance, suggestions will be appreciated.
>>
>>         1. Variation in eQuest and TRNSYS. (Blue and green is for eQuest and; Magenta
>>         and brown for TRNSYS)
>>
>>         <image.png>
>>
>>         2. eQuest and Energy Plus
>>         <image.png>
>>
>>
>>          Regards,
>>
>>         Mayank Bhatnagar
>>
>>         Energy Analyst
>>
>>
>>
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