[BLDG-SIM] IES<VE> Users

Thu Aug 2 17:34:36 PDT 2007

Having used iesVE for a just over a year now---still a relatively new user
of the tool, but one that has pushed it pretty hard along the way---the
following is an attempt to share a range of insights for those interested:

IES say they have put the simulation engine through the paces with the
various ASHRAE standard tests that Drury Crawley referred to; however, I've
not dug into the results of those tests specifically. I expect you could
obtain the results upon request.

My use of VE has been mainly for envelope performance, thermal, HVAC, and
natural ventilation simulations, plus some daylighting. This has included
modeling a range of less common strategies, such as double skins, actively
controlled openings, UFAD and displacement ventilation, and daylight
collectors. 

VE has allowed me to combine relative optimization of the building envelope
with radiant cooling (slab-integrated or panels) in various mechanical and
mixed-mode natural ventilation configurations in comparison to more
conventional approaches. These have included UFAD as well, wherein I've been
able to look at thermal decay in the underfloor plenum and radiant transfer
between the warm ceiling above and floor/plenum surface. VE's ability to
approximate double skins and stratified environments (essentially same as
COMIS), plus exceptional flexibility with regard to mixed-mode operation and
control of openings, were also significant benefits for in my work.

As part of my work at the CBE, I've also made some effort, though far from
exhaustive, to compare VE to other building simulation tools (note that I've
taken a fairly rough, spotty, apples & oranges approach and do not claim to
be an expert here). In this context I've been focused mainly on how various
tools handle or allow manipulation and control of parameters associated with
hydronic radiant cooling and bulk-airflow modeling across a range of
alternatives that include mechanical airside systems. While every tool has
pros and cons, my experience with VE is that it is overall the most useful,
flexible, and integrated set of tools for informing and developing design
alternatives, particularly for less conventional strategies that rely on the
building itself or an integrated systems approach more than mechanical
systems alone to achieve desired levels of indoor environmental quality. I
still use various supporting tools, such as LBNL's Window5 or specific tools
with Ecotect, plus other whole-building simulation tools, such as eQuest,
where they are better suited to particular problems. 

Some examples: 

Like eQuest, VE supports a progression of analysis from getting quick
answers in conceptual design to detailed analysis in DDs. While eQuest/DOE-2
has, without question, far more extensive capability for modeling a very
broad range of relatively conventional mechanical HVAC systems, my
experience has been that VE is much less constrained when it comes to
modeling various unconventional or building-integrated systems and has
considerably greater capability with regard to daylighting, natural
ventilation, etc. And, if your handy with juggling eQuest input files, you
can use eQuest to post-process VE results for certain mechanical elements,
such as water-side economizer operation. 

Similarly, it appears EnergyPlus may be more robust or accurate in certain
situations, though I've not yet come across this in my work. On the
contrary, many of the fundamental limitations I've found in VE, such as the
method for approximating view factors for radiant exchange, are essentially
the same in EnergyPlus. (Of course, there are surely relevant differences
I've not dealt with.) However, I have found some things I'd like to do, such
as controlled prioritization of hydronic cooling in a space using both
hydronic and air-side mechanical cooling, that can be readily done in VE
but, according to Rick Strand (who developed the radiant cooling module for
E+), are not presently possible in E+. I also prefer the degree to which VE
permits integrated analysis of natural ventilation (BAS-controlled or
otherwise). Finally, while the VE user interface still has a bit of a steep
learning curve and lots of room for improvement, it is quite workable and
currently well beyond the DesignBuilder interface for EnergyPlus (the best
E+ interface I'm aware of) in terms of providing a practical level of access
to the full range of simulation potential that the VE toolset offers. The
latter may be of value if you are looking for capability that is similar to
the combination of EnergyPlus, COMIS (or CONTAM), and Radiance, but with an
integrated user interface that is well suited to the pace and constraints of
design projects (as differentiated from research, for which one typically
has much more time). 

Similar comparisons can be made with TAS and TRNSYS. In the end, how you
intend to use the tool may be the most important determinant of which is
best for you.

My understanding is that the Revit plug-in, which takes the design process
integration one step further---porting geometry and building component
information directly from Revit into VE---is new enough that it works well
only for fairly simple stuff, but hopefully will improve in time. However,
my sense of these limitations is based only upon what I've heard and not
first-hand experience.

I have been impressed with the rate of development of VE and the
responsiveness of the IES technical staff. Rapid development of such a
complex tool definitely has both pros and cons: While some additional bugs
may missed before each new release, etc., in just over one year, the
development team has made exceptional progress and has added many
capabilities in direct response to user input. 

It may also be worth noting that a growing number of significant engineering
firms, such as the London offices of ARUP, Buro Happold, and KEEN
Engineering (now a part of Stantec), have come to rely on VE for many
projects. They might offer further insights.

Hopefully this has been helpful.

**********************************************

Timothy Moore
Integrated Sustainable Design Consultant 
LEED AP

Whole Systems Design
910 Indian Rock Ave.
Berkeley, CA 94707
Ph: (510) 525-4809
Fx: (413) 480-7252
Mobile: (303) 324-1044
 <mailto:tmoore at whole-systems-design.com> tmoore at whole-systems-design.com

Building Science Research and Simulation

Center for the Built Environment (CBE)
University of California at Berkeley
 <mailto:tcm at berkeley.edu> tcm at berkeley.edu 

  _____  

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Leonard
Sciarra
Sent: Thursday, August 02, 2007 7:14 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] IES<VE> Users

we just had one of the programmers in our office.  It looks pretty robust,
has a nice graphical interface and translator from our revit models, so for
us, that could save time.  Also, it has some good day lighting analysis
tools, so with the one model we can look at thermal performance and day
lighting.  that is intriguing.  that said, I haven't used it on a project
yet.

Leonard Sciarra, AIA, LEED ap

312.577.6580 (Dir)

G E N S L E R | Architecture & Design Worldwide

30 West Monroe Street

Chicago IL, 60603

312.456.0123

leonard_sciarra at gensler.com 

  _____  

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Staci
Jennings
Sent: Wednesday, August 01, 2007 1:29 PM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] IES<VE> Users

My company is considering purchasing the IES<VE> software, and the only
information I can find about it is from IES.  I'm hoping to find someone
using the software and get their opinion of it.

Staci Jennings 

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