[Bldg-sim] Solar gains differences between Design Builder and IES VE....

[Macdonald, Iain]

David,

I suspect that you are not comparing apples to apples. Intermodel comparisons are generally difficult to complete without a thorough understanding of the inputs and algorithms used in the tools. Its very easy to think you have equivalency in your input models when you do not. You have the added complication in your case that the DesignBuilder interface adds another layer of translation to the problem.

Also note that both simulation engines (IES VE and EnergyPlus) have been through the BESTEST/ASHRAE 140 process as well as many other validation exercises. This should mean that given the same input the output will be similar (within some bound due to different algorithms and implementations).

I suggest that you make a careful comparison of all the inputs and understand how they impact the simulation, then do the same with the output variables that you are comparing.

Regards,

Iain

From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of David GARCIA-SANCHEZ
Sent: November-23-12 8:23 AM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] Solar gains differences between Design Builder and IES VE....

Dear group,

In our current projects we noticed a big difference when modeling solar gains between the software IES VE and Designbuilder (EnergyPlus). IES VE underestimate the values of solar gains, by almost 1 to 2 of difference than EnergyPlus,

So I just try to ask if someone of you are experienced the same difference and if you know the reasons of that big difference. We test a "cell-test" and we found also this underestimation of solar gains.

Thanks in advance,

David Garcia Sanchez

[cid:image001.png at 01CDC96F.768FF0B0]

David GARCIA-SANCHEZ
greenaffair
Tel. +33 (0)1 46 03 80 10
Mobile +33 (0)6 78 15 08 09
102 avenue Edouard Vaillant - 92100 Boulogne-Billancourt
www.greenaffair.com<http://www.greenaffair.com/>



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