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

[Joe Huang]

Are you using the same weather file in all three programs?  The weather files contain the 
global horizontal and direct normal radiation (beam looking directly at the sun).  The 
different simulation programs take these and calculate the incident solar on each surface 
using similar algorithms.  However, when you compare radiation on different orientations 
where you set the clock, i.e., Time-Zone and Longitude, is very critical.

You should first figure out whether the weather files for the three programs come from the 
same source data  (you can convert from the EPW to a BIN if you're not sure (see  
http://doe2.com/index_Wth.html#eQ_WthProc ).  If the weather files are different, then
all bets are off, and the differences are due to the weather data and not the three programs.

If they are the same weather data,  you should check if you're inputting the same 
longitude and time-zone.  Since India is at GMT +5.5, but eQUEST accepts only integer 
time-zones, you'll likely see a half-hour difference in the hourly profile of radiation, 
which seems consistent with the first page of your spreadsheet where the eQUEST beam 
radiation looks a half-hour late. The comparison of the TRNSYS to the eQUEST curves 
(confusing because nothing is labeled) suggests they may be off by several hours.

Joe

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 9/24/2014 4:42 AM, Mayank Bhatnagar 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)
>
> Inline image 1
>
> 2. eQuest and Energy Plus
> Inline image 1
>
>
>  Regards,
>
> Mayank Bhatnagar
>
> Energy Analyst
>
>
>
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