[Equest-users] EnergyPlus--Quest Competitor or Natural Evolution

Karen Walkerman kwalkerman at gmail.com
Mon Apr 13 10:27:51 PDT 2009

I agree that there are some serious disconnects occurring between the
design, modeling, construction and building operation.  I have been on
projects where the design engineer claimed that all pumps will operate at
variable speeds, but no control valves were specified for coils, meaning
that while pumps are supplied with VSDs, no variable speed pumping is
actually possible.  I've also seen projects reported where the design team
touted the installation of high-efficiency boilers (94% or better), and then
also claimed to be saving pumping energy by running loop temperatures hot,
around 180 F.  You have to be very careful with this combination.  I don't
know of a boiler that can provide 94% efficiency at 180F supply water
temperature without some very fancy heat exchangers.

Sometimes field changes are made that cut into the energy performance of a
building.  Simple pipe distribution and pumping changes can have large
energy performance impacts.  Simple misplacement of a DP sensor in a pumping
loop can result in inadequate flow to heating and cooling coils.  This often
results in an efficient pumping system being forced into an all-on position
so that all systems are provided with adequate flow.  Each building tells
its own story.  I've seen fantastic engineers produce horrible models
because they understand how buildings work, but not how computer programs

When I first started watching this list-serve, someone said "if you can't
develop a simple excel spreadsheet calculation to estimate what you are
trying to model, you shouldn't be modeling it."  I think that we all need to
take this to heart.  You should be able to explain each and every result.
If you can't, look through hourly outputs.  See how the program is
calculating things.  Figure out what is going on.  All of the output reports
available from eQuest allow for a window into the calculation mechanism of
the program that is absolutely fantastic.  It is unlikely that I will use a
modeling program that doesn't provide me with this sort of transparency, and
post-processing ability.

I have looked through Energy Plus.  On the surface it seems that there's
some valuable functionality available that is not currently available in
eQuest, but without a fully-functional graphical user interface, and
extensive testing, none of that matters.  Precision does not equal accuracy.


On Mon, Apr 13, 2009 at 12:32 PM, Carol Gardner <gems at spiritone.com> wrote:

> I agree with Glenn. I have always regretted the split that occurred between
> the eQUEST team and the EnergyPlus team that occurred lo so many years ago
> now. We users have paid for that the most. Just think what tools would be
> available right now if all those experts were still working together.....
> William cited operations as the reason for green buildings not performing
> as they should; Dan thinks it is the tool's fault. I think we, as energy
> modelers, better look in the mirror to see who is at fault. There are a lot
> of untrained new people entering this field who think that by possessing an
> engineering degree, or some other advanced degree, they should be able to
> jump right in and do this work. I have been doing it for 25 years now using
> a variety of tools and I can tell you that any tool I use is only as good as
> my ability to make it work, and I am still learning how to do that.
> It is not correct to assume that the funding for eQUEST is insignificant
> just because federal $ are no longer available for it. As far as I know
> eQUEST is funded at a level that the current eQUEST team is hard pressed to
> spend because there are not enough of them doing the work as well as not
> enough hours in the day. Also, they are constantly making changes and
> improvement which address the past concerns that people had about the
> algorithms, heat balance methodology, etc.
> Each team, the EnergyPlus team and the eQUEST team. is composed of highly
> educated and trained professionals that are capable of developing great
> tools for our use. Each one will eventually function as well as a user can
> make it function. And, that again is the biggest problem. The user, not the
> tool. We can wish for a model to do this or to do that but as long as there
> are users out there, you know who you are, who are untrained and
> inexperienced, bad results will be obtained using whatever tool is used.
> Carol Gardner PE
> Glenn Haynes wrote:
>> Mr. Koran has made some good points on the power of government funding to
>> assure that EnergyPlus will eventually overtake DOE2 and eQuest. But this
>> doesn’t guarantee a better simulation code. Doe2 has the backing of decades
>> of usage and testing by millions of experienced building simulation modelers
>> worldwide. It has undergone thousands of corrections and improvements during
>> its lifetime, and has evolved to the point that it has been widely accepted
>> and used as the benchmark by which other simulation codes are tested and
>> proven.
>> So my advice is let’s not be hasty in writing off such a powerful legacy
>> and jumping to something newer just because it is receiving more funding at
>> this point in time. Wasn’t DOE2 conceived and developed under federal (DOE)
>> funding decades ago? Do we need to start over with a new baby? We can all
>> point out weaknesses in a tool that we are all intimately familiar with, but
>> have we spent enough time and effort to look as carefully and critically at
>> EnergyPlus? Not yet, because we can’t until EnergyPlus (or any other newer
>> software) has undergone as much usage and scrutiny as DOE2 and its
>> derivitives.
>> No matter how much money is spent on a newer code, I will personally put
>> more faith and confidence in the more tried and proven code. That kind of
>> confidence can’t be bought; it can only develop over a long time. When
>> EnergyPlus has been proven to my satisfaction to be better than DOE2, then I
>> will be happy to switch.
>> Remember McIntosh computers and their windows GUI? Has Microsoft created a
>> better product? I don’t think so, but we have been unhappily forced to
>> switch because most other people have, and it was all due to money and its
>> power, not a better product. As grass roots users of DOE2, let’s stick
>> together and demand that EnergyPlus be proven to our satisfaction to be at
>> least as good as DOE2 before we switch. After all, we pay our government to
>> serve our needs, not to use our money to dictate our choices.
>> Glenn Haynes, PE
>> ------------------------------------------------------------------------
>> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
>> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *Bill
>> *Sent:* Sunday, April 12, 2009 11:00 PM
>> *To:* Dan.Monaghan at bentley.com; equest-users at lists.onebuilding.org
>> *Subject:* Re: [Equest-users] EnergyPlus--Quest Competitor or Natural
>> Evolution
>> I work mostly in the existing buildings (non- or pre-"green) markets, but
>> to the extent green buildings don't live up to the promises is largely due
>> to operaitons, not design. Many green buildings are more complex, and since
>> even more traditional buildings typically have significantly sub-optimal
>> operations, it is only logical that green buildings will suffer at least as
>> much when compared to expectations/simulation results.
>> Some interesting documentation of green building performance is available
>> at www.newbuildings.org <http://www.newbuildings.org>.
>> As far as Energy Plus and eQuest, I only have experience with DOE-2 and
>> eQuest. EnergyPlus should be superior since it was built using the best of
>> DOE-2 and BLAST. IIRC, it was moving away from a transfer-function-based
>> simulation to a heat balance-based simulation. This should also help it to
>> be superior in some circumstances. DOE-2 derivative simulation tools are
>> generally weak at simulating suboptimal operations, and are very poor at
>> simulating certain controls improvements or retrocommissioning measures. I
>> don't know how much better EnergyPlus is in this regard.
>> At any rate, because of federal funding, and that some (many/most?)
>> federal projects and organizations will only allow EnergyPlus, it seems
>> certain that EnergyPlus is the future. My use of DOE-2 dates back to before
>> there were convenient interfaces and we dealt only with BDL and user-defined
>> functions, and we needed the stacks of documentation to know what we were
>> doing. I certainly believe that as more interfaces for EnergyPlus are
>> developed, more students come out of school with knowledge of EnergyPlus,
>> and more of us learn EnergyPlus, it will see greater and greater use.
>> William E. Koran, P.E.
>> Senior Engineer
>> Q u E S T
>> Quantum Energy Services and Technologies
>> Web: www.quest-world.com <http://www.quest-world.com/>
>> ------------------------------------------------------------------------
>> *From:* equest-users-bounces at lists.onebuilding.org [mailto:
>> equest-users-bounces at lists.onebuilding.org] *On Behalf Of *
>> Dan.Monaghan at bentley.com
>> *Sent:* Sunday, April 12, 2009 7:05 PM
>> *To:* equest-users at lists.onebuilding.org
>> *Subject:* [Equest-users] EnergyPlus--Quest Competitor or Natural
>> Evolution
>> Thanks to all the people who responded to my question.
>> A few of you ask me to post the result from my very unscientific survey.
>> The list is split 50%, 50% in their opinion that EnergyPlus will become a
>> natural transition to eQuest.
>> The basic sentiment is that eQuest is recognized to be less capable, but
>> faster and easier to use.
>> However, almost all who responded recognized that as the demand for
>> high-performance buildings grows, the ability to/ //accurately/ predict
>> energy consumption, C02 emissions, occupant comfort and life cycle costs are
>> going to become more important. I read this to mean that the demand for
>> detailed analysis tools like EnergyPuls is likely to increase.
>> Someone asked me why Bentley cares. We believe that there’s a hole in the
>> U.S. energy analysis/simulation market. We believe, as this survey
>> indicates, that the tools available to U.S. designers seem to fall into two
>> camps. Tools that are easy-to-use, but inaccurate/incomplete. Or, tools that
>> are precise, but difficult to use and slow.
>> Unfortunately, because of this we see:
>> 1. Many “green” building don’t live up to the promises
>> 2. Robust energy simulation is typically reserved for “special” projects,
>> or certain project types.
>> 3. Accurate energy analysis is typically siloed, as oppose to integrated
>> into the design process
>> As the leader in building engineering and analysis software or mission is
>> “sustaining the worlds infrastructure”. As such we’re working on solving
>> this problem, www.bentley.com/eps <http://www.bentley.com/eps>.
>> *Dan Monaghan | Global Marketing Manager
>> Building Performance Group*
>> *Bentley Systems, Incorporated*
>> *Phone*: +1-410-207-5501| *Skype*: dmonaghan.skype
>> *E-mail*: dan.monaghan at bentley.com <mailto:christine.byrne at bentley.com>*
>> **| URL:* www.bentley.com <http://www.bentley.com>
>> *Address*: Bentley | 40 Dunvegan Rd. | Baltimore| MD | 21228 | USA
>> Picture (Device Independent Bitmap)
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