Building envelope

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Good afternoon

My name is Alex, and I'm new to building simulation world , and i saw you have many simulation software ,

1.from my understanding the most used ones are eQuest and Trace 700, is it true ?,
what the difference between these two,

2.i would like to simulate more building envelope, what software suit more for that ?

Thank you very much for your support and help

with best regard

Alex

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Hi Alex,

welcome to the world of nerds ;-)

There is an intersting document to start with:
http://apps1.eere.energy.gov/buildings/tools_directory/pdfs/contrasting_the_capabilities_of_building_energy_performance_simulation_programs_v1.0.pdf

That will probably get you a nice intro. If you are into the maths and
equations, check out Joe Clarke's book on building simulation.
Also Jan Hensen recently published one on building simulation.

Good luck and welcome!

Leen

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Dear All,

The paper from referred to by Alex is no 6-7 years old. There has been a lot
of movement in building simulation since then.

Has anyone published formally or informally anything since 2005?

Thanks

Mark Dewsbury (PhD)

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My advise to Alex is to start with Energy Plus, as it has the most
development put into it and the mose capabilities.
Also Open studio has some great information as to where to start.
http://openstudio.nrel.gov/

Jeremiah Crossett's picture
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Also to Alex, eQuest is where most people start.
A great and affordable class on eQuest can be found here
http://energy-models.com/training/equest
(I just took it and found it to be very insightful)

Jeremiah Crossett's picture
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I do not think it is a good idea for a beginner to start with Energy Plus.
Bear in mind, it is not so user friendly. Even a senior energy modeler may
not be able to grasp it easily. Equest is more strait-forward to my mind.

Regards,

Cheney

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Alex,

I would agree with Cheney here. The wizards available in eQuest will allow you to create and simulate typical buildings and various scenarios relatively quickly and easily and with a good level of confidence. The documentation which accompanies the eQuest download contains very useful reference and guidance documentation.

Good luck.
Chris

Chris
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Is anybody interested in dueling software? My idea (and I'm sure it's
been done before)...

We define an easy building and everybody models it in whatever they own
and we compare the results.

Sound like fun?

Robert Wichert P.Eng. LEED AP

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Dear Robert,

That's basically what is done by ASHRAE Standard 140, I think. Modeling an
"easy" building is not the problem, though. Modeling a "messy" building is
the challenge and I am not sure, but doubt that a good comparison could be
made since most of the energy analysis software does not allow close
scrutiny of detailed results.

James V. Dirkes II, P.E., BEMP , LEED AP

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Speaking from an architects perspective and admittedly novice energy simulator, Equest was pretty easy to access, and after going to one of the Equest courses, that made it even more useful. Alex, however, your tag line indicated you are involved in houses, so in that case Equest may not be appropriate, unless they are large multi-family types.

Leonard Sciarra

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Hi Alex,

There?s been a lot of good feedback on these lists. I think a question to keep in mind while picking a modeling software is: what is your target building and target output?

You mention envelope performance ? I?ve used some fenestration (window) specific modeling tools in the past when the building type is appropriate and the level of detail needed is not as high as to require a full eQUEST/EnergyPlus model.

Comfen and Resfen developed by LBNL are great tool for commercial and residential analyses of fenestration impacts. I?m sure there are very many other tools that focus on components of a building. That may be an option for you as well.

From one Alex to another, if I had to pick one, my vote would be for eQUEST as an accessible modeling environment with a great user-base (this list-serv and the archives) as well as many people teaching eQUEST classes across the country.

Cheers,
Alex Krickx

Alex Krickx, LEED AP

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To Alex C and to add to the last email from Alex K, you might take a closer
look at COMFEN and RESFEN.
Each focuses on quick assessment of window/facade performance with a
minimal learning curve but using powerful analysis engines.

RESFEN (RESidential FENestration) is a two screen interface (text only) to
DOE-2; with a one screen input it runs a highly defaulted "typical" house
but allows all the fenestration related parameters to be selected and
varied, and provides house energy performance and cost data for output.
Download at http://windows.lbl.gov/software/resfen/resfen.html

COMFEN (COMmercial FENestration) is an easy to use but very powerful
interface to EnergyPlus. It does full building systems analysis for
multiple "spaces" - on an annual basis, with default HVAC/operating
schedule etc. It is graphically oriented and "architect friendly", having
been designed with extensive input and collaboration from A/E teams and
consultants. It provides virtually complete access to design and analyze
any fenestration system- you can select from 3000+ glazings from the
WINDOW6 data data base, choose framing sytems, design the facade with
multiple windows, add interior or exterior shading, daylighting etc It
provides graphic access to all the EnergyPlus climate data. There are
multiple options for graphic display of output from annual to monthly to
hourly data; energy/peak/comfort/carbon, etc For 5 zones, on a standard
laptop for an annual 8760 hr calc it takes 30-60 sec; It includes glare
analysis of facades at user specified hours with a link to Radiance. The
next version will include some natural ventilation strategies and some new
cost databases. There are tutorial movies and a user manual; You can
access free downloads at http://windows.lbl.gov/software/comfen/comfen.html
See sample output at
http://windows.lbl.gov/software/comfen/4/comfen_screens.html
provide feedback or ask questions at COMFENHelp at lbl.gov
We plan to add additional new features this year so feedback is welcomed.

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

Stephen Selkowitz

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

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Though I do not retract my statement with regards to energy plus and open
studio, I do agree that eQUEST is a great starting point.

I tend to use both, (eQUEST for preliminary, then Energy Plus, then
crossrefrence my Energy Plus model output with the eQUEST run) but started
with Energy Plus because I wanted to be able to model more then just
thermal and electrical energy systems such as, green roofs, solar electric,
solar thermal, vertical & horizontal wind turbines and have been recently
been modeling phase change materials. At first it was a bit intimidating,
but I got a feel for it pretty fast and now do not find the IDF editor to
be a difficult of an interface for input data, and google sketch up can be
used for the geometry and thermal zones.
The exciting thing about energy plus is the open source tools available
from NREL's Open studio project.
http://openstudio.nrel.gov/

And the new "Simergy" interface being realised by Laurence Berkley in April.
http://eetd.lbl.gov/bt/simergy/key.html

Bently havacomp has a new interface as well
http://www.bentley.com/en-US/Products/Hevacomp+Dynamic+Simulation/

And then there is design builder:
http://www.designbuilder.co.uk/content/view/29/44/

To me it makes more since to start with the latest and most powerful
software, that is being funded by the USDOE and is updated every 6 months.
eQUEST is great, but in the long run Energy Plus is a more valuable skill
set in my opinion. Also there are more features, and you can do interesting
things with the output...

A good example of something that is (from my understanding) not possible
with eQUEST my current research for phase change materials, is visualized
in this model of the generic phase change materiel from an example file, as
compared to a baseline building..( currently working on the new version
with bioPCM product data.).
https://docs.google.com/a/setnrgh2o.com/spreadsheet/ccc?key=0Angnu5sp0FF9dFB6RlNYSkZyMW5MUTd0cmNxZGhpbnc&hl=en_US#gid=28

To Robert I am very interested in dueling software! I also have a small
factory that I have yet to do the simulation for with drop box full of
details we could use in the duel ! Please let me know if you want to as it
sounds fun:)

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Thank you for the advice,
how about doors, walls, floors and roof ? where I can simulate those ?

Thank you for your time

Have a great day today and a wonderful weekend
Alex C

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I'm up for it. Jeremiah is up for it. Anybody with Trace up for it? I
only have EnergyPro.

Robert Wichert P.Eng. LEED AP

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Yes, of course. I was thinking of a non-residential one-story wood
frame, steel studs, or concrete block building with one or two windows
per side and a cathedral ceiling on a poured slab. A basement would be
OK too, but not really necessary. Either no zoning at all or a core for
toilets/break rooms and open plan office all around.

I mean REALLY simple.

Robert Wichert P.Eng. LEED AP

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Now THAT would be a better test than I envisioned, Jon. I was just
thinking of comparing models, NOT comparing them to a real building.
Sounds like fun though!

Robert Wichert P.Eng. LEED AP

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I have two office buildings with data, including energy star portfolio
manager data, and actual utility meeter data. Also I have
architectural data on them. For the one I have three years data on, the
other only one year. See the attached for the one with the best data and
let me know if one of these works..

Jeremiah Crossett's picture
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What would be really interesting is if multiple people would model the same
building in the same code, like have two energy Plus simulations, 2 TRNSYS,
2ESp-r, ... to see how, based on the same information, results might differ
...

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Jeremiah,

it is already a pretty large building. I assume most people are like me ...
really occupied. A small thing can be smached in between, but not something
that might take me 6 to 8 hours to analyse and model. Should we not look
for something smaller? A might be able to get some data on a passive house
in Belgium. Something less than 200 m2, measured during over a year.

Leen

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Dear Gents,

I have some toys

Mark Dewsbury (PhD)

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These are great, I wonder if when simplfying energy modeling you loose the
value of some software tools? Without such things as windows, lighting,
HVAC, etc some software may seem like it is a better tool, but then
modeling real world buildings another software tool may work better.. Just
a thought...

Jeremiah Crossett's picture
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For software calibration we start with the simplest envelope of all first.
We can then establish which algorithms require tweaking. We can then change
bits and see what happens.

We have identified many aspects of the HER software requiring further
investigation.

We are now in the last stages of some intensive subfloor research.

About to look at reflective versus bulk subfloor insulation, followed by
thermal mass.

We can mimic internal heat loads and HVAC operation.

Windows one day in the future when the other envelope elements are tested.

Mark Dewsbury (PhD)

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I use EnergyPro and its floor elements are basic, basic, basic. Slab,
floor with crawlspace, floor without crawlspace. I don't know what you
call that building you have with stilts.

But if you have response information on your buildings, they would be
easier to model than a six story building, that's for sure!

Robert Wichert P.Eng. LEED AP

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Hi Jeremiah,

Please see the more detailed email I just sent you. Just to make sure other members don't do repeat the work I did. I think the problem with your files is that the construction object you are putting the PCMs (Drop Ceiling) was never linked to any of the surfaces of your building (In BuildingSurface:Detailed).

Please let me know if this solves your problem.

Best,

Paulo

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FYI...

If you are thinking about how accurate an energy model may or may not be, there has been quite a bit of work done by the ASHRAE Standard 140 over the last 20 years, including: empirical, comparative and analytical models of the building envelope, air side systems. Standard 140 is a standard method of test for simulation that is used by others to see if the algorithms inside the program are performing correctly. The IEA and others have tests as well, which include side-by-side test boxes.

Jeff

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Yes, good idea, Jeff. "Ease of use" isn't in there, but then, I guess
that's not always important.

Do you know of any papers that compare EQuest to EnergyPro to EnergyPlus
to DOE-2 to TRACE-700 to anything else using ASHRAE 140?

Maybe the publishers of these models have done the ASHRAE 140 work and
would allow us to see it, but "Ease of Use" is not on their list!

Robert Wichert P.Eng. LEED AP

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Std 140 comes with example results from various software programs. However
many tools also publish reports comparing their 140 results on their web
sites. That information is required to be certified as software for use
for the tax credits for commercial buildings:
http://www1.eere.energy.gov/buildings/tax_commercial.html and
http://www1.eere.energy.gov/buildings/qualified_software.html

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In addition to the IEA and ASHRAE validation work already described there are also a bunch of CEN standards for energy simulation tools.

One interesting development from a few years ago that may be of interest was that the actual models used for the validation tests for the ESP-r tool were embedded into the software (i.e. they are distributed with it and can be invoked by users from the interface). This gives the user two opportunities: they can check that they get the same answer on their OS/hardware and they can see how the 'experts' modelled the test cases.

Iain

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FYI.

RP1468, which involves developing guidelines for BIM to thermal models, is currently in progress and scheduled for completion in June 2012. It has one test case that attempted to compare DOE2.1e to DOE2.2 and EP+ for the SAMP1E, run 3A file. The results show 2.1e and 2.2 only agree at the envelope level to within 20% (I.e. System sum) or so, and 2.1e to EP+ has even larger disagreement. The final report will have over 1 GByte of files for review, including Autodesk, Bentley and Archicad BIM files for about 20+ test cases.

So, there is still work to do, especially when one considers that development work for 90.1, 90.2, and 189 are now only being simulated with EP+, which means users who uses a DOE2 derivative for 90.1 compliance will have trouble duplicating the tabulated results in the standard within 20%.

Std 189 will eventually have even more trouble as it also covers peak reductions, yet has scant advice has been provided about how to calculate peak loads using a simulation and TMY2 or TMY3 weather files...which will oversize if one is not careful.

Jeff

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