[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[EnergyPlus_Support] Re: need help w/ monthly gas usage results
Dear Dimos,
Now that I think about it a bit, I wonder......
It occurs to me that all of the normal HVAC objects expect a
thermostat which controls to the zone temperature setpoint. Your
situation does not fit that scenario. It would be challenging to try
to define a scenario that treated the oven as a temperature zone; you
would have to define a separate zone for the oven, with walls and roof
that matched the actual construction ... and then define a complete
heating system for that zone. Even then, there are probably warmup /
cooldown cycles for the oven that would not be handled well by an E+
thermostat.
So....
As I recall, your Gas Equipment object uses the same amount of gas
constantly. If you got good agreement with your utility bills
previously, you should be able to duplicate that with an equivalent
amount of energy in the Steam Equipment object. I think (you should
check) that the Steam Equipment object assumes that the steam is at
standard atmospheric pressure, so your steam flow will be higher than
the process equipment if the process equipment operates at a higher
pressure. (In other words, adjust the steam flow to the equivalent
rate at sea level atmospheric pressure.)
Finally, the Schedule field of the Steam Equipment object should give
you plenty of flexibility to fine tune the energy use.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, D T <ellinas.1984@...> wrote:
>
> The facility I am modeling uses a natural gas-fired fire-tube steam
boiler to heat the water and convert it into steam for this facility's
process. Since natural gas is the fuel that is being used, I am trying
to validate the facility's monthly gas energy usage. When I lumped the
ovens and the boiler in the gas equipment object, I was able to
successfully obtain the monthly gas usages and gas cost (from the
tariff I applied) with EnergyPlus. The usages and costs compared well
with the actual bill data.
>
> But, since there's a boiler object in EnergyPlus, I think it would
be better to use that. I've never used the steam boiler object
before and this is why I'm having so many problems. It looks like I
have to add a steam loop if I want to correctly model the facility.
What do you think?
>
> Dimos
>
> p.s. I find the ABUPS report useful because it gives you a total
report on the facility energy usage. It's helpful for the project I am
working on.
>
>
>
>
>
> --- On Thu, 8/7/08, JV Dirkes II <jvd2pe@...> wrote:
>
> From: JV Dirkes II <jvd2pe@...>
> Subject: [EnergyPlus_Support] Re: need help w/ monthly gas usage results
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Date: Thursday, August 7, 2008, 6:55 PM
>
>
>
>
>
>
> Dear Dimos,
>
> It makes sense to me that the Steam Equipment object reports energy in
> a purchased heating category because it's not associated with a
> "known" HVAC energy source like a boiler. It could actually be a
> number of independent steam sources that are unrelated to HVAC.
>
> That said, I still don't know anything about the ABUPS report, since I
> haven't used it before. Maybe I should check it out on my next
> project, since you are finding it useful....
>
> p.s., How much trouble could it be to just add the purchased heating
> energy to the other gas usage? It seems as though that wouldn't be
> too difficult...
>
> --- In EnergyPlus_Support@ yahoogroups. com, D T <ellinas.1984@ ...>
wrote:
> >
> > sorry... i misspoke, it's supposed to read "steam equipment object"
> in the second paragraph not "steam boiler object". Same thing goes
> with the last paragraph. I meant steam equipment object
> >
> > --- On Thu, 8/7/08, D T <ellinas.1984@ ...> wrote:
> >
> > From: D T <ellinas.1984@ ...>
> > Subject: Re: [EnergyPlus_ Support] Re: need help w/ monthly gas usage
> results
> > To: EnergyPlus_Support@ yahoogroups. com
> > Date: Thursday, August 7, 2008, 6:32 PM
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > Thank you very much for the help. I read through all the comments
> and objects that you had marked through. I made all the changes you
> had suggested to the file, but I was still getting an error with one
> of the branch nodes after re-running the simulation. I think I will
> follow your suggestion to use the steam object for the boiler. Though,
> as you said, it won't capture the sophistication of a boiler, it does
> look a lot easier to work with and provides a good approximation.
> >
> > When I used the steam boiler object, I got energy usage results.
> However, this energy was under purchased heating, which is not
> correct. How do I get it to not fall under this category in the ABUPS
> report?
> >
> > As far as how I specified each zone, you are correct. The only
> exception is zone 1441 which is actually a freezer, but DesignBuilder
> did not have that option so I tried modeling it as best I could for
> the time being, knowing that I would change it later. I will probably
> use the refrigeration object for that zone because ammonia compressors
> service that zone.
> >
> > I appreciate all the help you have provided. If I could get the
> results from steam object to not fall under purchased heating, that
> would be great.
> >
> > Thanks again,
> > Dimos
> >
> >
> >
> > --- On Thu, 8/7/08, JV Dirkes II <jvd2pe@> wrote:
> >
> > From: JV Dirkes II <jvd2pe@>
> > Subject: [EnergyPlus_ Support] Re: need help w/ monthly gas usage
> results
> > To: EnergyPlus_Support@ yahoogroups. com
> > Date: Thursday, August 7, 2008, 3:08 PM
> >
> >
> >
> >
> > Dear Dimos,
> >
> > I took the liberty of making some suggestions for your .idf and have
> > uploaded them in a Microsoft Word document for your review. All
> > changes are highlighted with a yellow background. Anything that I
> > thought should be deleted uses a "Strikethrough" font; if you agree
> > that it should be deleted, you will have to actually delete the text.
> >
> > My own comments are in a red font. All suggestions and comments are
> > based on the understanding that the assumptions in my previous post
> > are correct...
> >
> > --- In EnergyPlus_Support@ yahoogroups. com, D T <ellinas.1984@ ...>
> wrote:
> > >
> > > Thanks for the suggestions from you and Richard. I modeled this
> > facility using DesignBuilder and imported the idf file into
> > EnergyPlus. In the model, I have DX cooling along with split
> > system/gas furnace for heating in the office area. The largest zone
> > (zone 1405) has no heating. It only uses mechanical ventilation and
> > outside air. The hot water boiler was added in there from
> > DesignBuilder for the gas furnace in the office area. If I'm correct,
> > I don't think that zone I designated as the offices is being heated.
> > >
> > > I deleted the Furnace:heating object because I don't need to
> > heat zone 1405 with the either the steam boiler nor the hot water
> > boiler. Rather, the steam from the steam boiler is being used for a
> > process in the zone.
> > >
> > > I tried connecting the appropriate branches and/or coils to the
> > steam boiler, but I'm still having problems. Though the errors aren't
> > fatal, I am still not getting gas usage values from the steam boiler.
> > I'm having problems with node connections for the steam boilers.
> > Something is not correct and, despite the error messages, I still
> > cannot figure out how to correct it.
> > >
> > > Any help or suggestions as to how I can fix this problem are
> > appreciated.
> > >
> > > Thanks,
> > > Dimos
> > >
> > >
> > >
> > > --- On Wed, 8/6/08, JV Dirkes II <jvd2pe@> wrote:
> > >
> > > From: JV Dirkes II <jvd2pe@>
> > > Subject: [EnergyPlus_ Support] Re: need help w/ monthly gas usage
> results
> > > To: EnergyPlus_Support@ yahoogroups. com
> > > Date: Wednesday, August 6, 2008, 9:05 PM
> > >
> > >
> > >
> > >
> > >
> > >
> > > Dear Dimos,
> > >
> > > In addition to Richard's comments, I suggest....
> > >
> > > I'm not sure why you are trying to use both hot water AND steam
> > > boilers on the same building, but consider these suggestions. ..
> > >
> > > 1) Use a fan coil with hot water heating for Zone 1405 and
delete the
> > > furnace. You can get both heating and cooling from that single
object
> > > and ignore the Steam Boiler completely.
> > > 2) If you need to provide outdoor air to zone 1405, and it must use
> > > heat from the boiler, you'll have to abandon the Furnace and instead
> > > create an air handler with OA mixer, cooling coil and heating coil.
> > > The Branch will look something like...
> > >
> > > BRANCH,
> > > Branch_AirLoop_ AH1, !- Branch Name
> > > Autosize, !- Maximum Branch Flow Rate {m3/s}
> > > OUTSIDE AIR SYSTEM, !- Comp1 Type
> > > OASystem_AH1, !- Comp1 Name
> > > NodeOut_RFan_ AH1, !- Comp1 Inlet Node Name
> > > NodeOut_MA_AH1, !- Comp1 Outlet Node Name
> > > PASSIVE, !- Comp1 Branch Control Type
> > > DXSystem:AirLoop, !- Comp2 Type
> > > DXAirLoop_AH1, !- Comp2 Name
> > > NodeOut_MA_AH1, !- Comp2 Inlet Node Name
> > > NodeOut_ClgCoilAir_ AH1, !- Comp2 Outlet Node Name
> > > PASSIVE, !- Comp2 Branch Control Type
> > > FAN:SIMPLE:VARIABLE VOLUME, !- Comp3 Type
> > > SFan_AH1, !- Comp3 Name
> > > NodeOut_ClgCoilAir_ AH1, !- Comp3 Inlet Node Name
> > > NodeOut_SF_AH1, !- Comp3 Outlet Node Name
> > > ACTIVE, !- Comp3 Branch Control Type
> > > COIL:WATER:SIMPLEHE ATING,!- Comp4 Type
> > > HtgCoil_AH1, !- Comp4 Name
> > > NodeOut_SF_AH1, !- Comp4 Inlet Node Name
> > > NodeOut_Air_ AH1, !- Comp4 Outlet Node Name
> > > PASSIVE; !- Comp4 Branch Control Type
> > > Of course, you will need Splitter, Mixer, Direct Air and a
variety of
> > > other objects to make the Air Loop complete; Don't forget those! It
> > > will become very similar to your other two zones.
> > >
> > > 3) Your Steam Boiler has only one branch, named "1405 branch".
At the
> > > least, if you keep the Steam Boiler, you will need an inlet and
outlet
> > > branch, similar to what you've created for the Hot water Boiler.
> > >
> > > 4) The Steam Boiler now has inlet and outlet nodes that look
> > > incorrect. They appear to be from an air loop....
> > >
> > > That's all for now.1
> > >
> > > --- In EnergyPlus_Support@ yahoogroups. com, D T <ellinas.1984@ ...>
> > wrote:
> > > >
> > > > Thanks for the suggestions. I created a Coil:Steam:AirHeati ng
> object
> > > and connected it to the Furnace:HeatOnly object. However, I am
having
> > > problems connecting the Furnace to the boiler. I read the error
> > > messages I am getting and I still cannot figure out how to fix the
> > > problem. Apparently I am having a problem with the branches and
nodes.
> > > I created an AirLoop for the steam boiler. More or less, I am having
> > > trouble figuring out how to correct my errors. Any help or
suggestions
> > > are appreciated.
> > > >
> > > > Thanks,
> > > > Dimos
> > > >
> > > > P.S. I've uploaded my file.
> > > >
> > > >
> > > > --- On Mon, 8/4/08, JV Dirkes II <jvd2pe@> wrote:
> > > >
> > > > From: JV Dirkes II <jvd2pe@>
> > > > Subject: [EnergyPlus_ Support] Re: need help w/ monthly gas usage
> > results
> > > > To: EnergyPlus_Support@ yahoogroups. com
> > > > Date: Monday, August 4, 2008, 9:07 PM
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Dear Dimos,
> > > >
> > > > I took a look at the new file, and it appears that:
> > > >
> > > > 1) You have two air loops. Each of those has a
Furnace:HeatCool. One
> > > > of the furnaces has a gas heating coil and the other has an
electric
> > > coil.
> > > > 2) You have a "Boiler:simple" (which is a hot water boiler) and a
> > > > "Boiler:Steam" , but the only thing using either one is the Fan
> > Coil in
> > > > Zone 1405.
> > > > 3) Therefore, neither of the Furnaces will use any energy from the
> > > > Boilers because they're not using hot water or steam coils. In
> > > > addition, the Boiler:Steam will not use any gas, because it has
> > > > nothing connected to it.
> > > > 4) If the Fan Coil has any load, the Boiler:Simple will provide
> it ...
> > > > as long as the Boiler is available and the Fan coil operates.
> > > > 5) Finally, you have created a Gas Equipment object called
"Boiler",
> > > > but it is not connected in any way with the heating loads, and
> > > > therefore is not useful to you.
> > > > 6) I think you should:
> > > > a) Delete the "Boiler" Gas Equipment object. This is not the
correct
> > > > approach for a heating load.
> > > > b) Connect the heating devices (Fan Coil or Furnace, whichever is
> > > > proper) to the Boiler:Simple or Boiler:Steam. If you use
> > > > Boiler:Steam, you'll need a Coil:Steam:AirHeati ng object in the
> > > > Furnace or Fan Coil.
> > > > c) Check the Fan Coil operation and confirm that it operates and
> also
> > > > has some heating to perform. Also check to see that the
> Boiler:Simple
> > > > is operating when you need it.
> > > >
> > > > That's all I can figure out right now. Good luck!
> > > >
> > > > --- In EnergyPlus_Support@ yahoogroups. com, D T
<ellinas.1984@ ...>
> > > wrote:
> > > > >
> > > > > Thanks for the help. I modeled the ovens using the GAS EQUIPMENT
> > > > object as well as the boiler. I did this in order to get
monthly gas
> > > > usage values for one entire year for the entire faclity. They
> closely
> > > > matched the faclity's gas bills. For the boiler, I used the GAS
> > > > EQUIPMENT object because I had some problems using the STEAM
BOILER
> > > > object in EnergyPlus.
> > > > >
> > > > > I specified all the inputs in the STEAM BOILER object yet I
don't
> > > > get any monthly output results. I do not know why I am not
> getting any
> > > > values for the steam boiler. Do you know why this could be
> happening?
> > > > Also, I have yet to specify the fans for the ovens. But, I would
> like
> > > > to ask, under which object in the Fans category of EnergyPlus
> would I
> > > > use to model the fans?
> > > > >
> > > > > Thanks again for the help. I will upload my idf file.
> > > > >
> > > > > Dimos
> > > > >
> > > > > --- On Fri, 8/1/08, JV Dirkes II <jvd2pe@> wrote:
> > > > >
> > > > > From: JV Dirkes II <jvd2pe@>
> > > > > Subject: [EnergyPlus_ Support] Re: need help w/ monthly gas
usage
> > > results
> > > > > To: EnergyPlus_Support@ yahoogroups. com
> > > > > Date: Friday, August 1, 2008, 1:26 PM
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > Dear Dimos,
> > > > >
> > > > > Here's my opinion:
> > > > > 1) Boiler:Steam sounds like a good choice. In my experience, the
> > part
> > > > > load ratio coefficients make a big difference, so I encourage
> you to
> > > > > take some time to get realistic values of these coefficients
> for the
> > > > > boiler.
> > > > > 2) The Gas Equipment object looks suitable for an oven. Assuming
> > that
> > > > > this is an oven type that is used for drying products or curing
> > paint,
> > > > > the radiant fraction will be 0, the latent fraction will be 0,
> > and the
> > > > > fraction lost will be about .20 - .25. A bakery oven will use
> > similar
> > > > > fractions. You will have to determine the schedule of
> operation and
> > > > > load.
> > > > > 3) Finally, ovens often have a fan for the burner, another for
> > exhaust
> > > > > and sometimes a fan for circulation; the energy for these fans
> > should
> > > > > be included in your model.
> > > > >
> > > > > --- In EnergyPlus_Support@ yahoogroups. com, D T
> <ellinas.1984@ ...>
> > > > wrote:
> > > > > >
> > > > > > Thanks for the suggestion. Since I have never modeled
> boilers nor
> > > > > ovens in EnergyPlus, could you perhaps steer me toward the
> objects I
> > > > > would need to work with. I know that for boilers there are
several
> > > > > objects. The plant I am modeling uses boilers for steam
> > generation, so
> > > > > would I need to use the steam boiler option? Also, for the
> > ovens, what
> > > > > object do you suggest I work with?
> > > > > >
> > > > > > Assuming I get these to work properly after modeling them, how
> > would
> > > > > I get them to report in the ABUPS report?
> > > > > >
> > > > > > Thanks in advance for helping me with this.
> > > > > >
> > > > > > Dimos
> > > > > >
> > > > > >
> > > > > >
> > > > > > --- On Thu, 7/31/08, JV Dirkes II <jvd2pe@> wrote:
> > > > > >
> > > > > > From: JV Dirkes II <jvd2pe@>
> > > > > > Subject: [EnergyPlus_ Support] Re: need help w/ monthly gas
> usage
> > > > results
> > > > > > To: EnergyPlus_Support@ yahoogroups. com
> > > > > > Date: Thursday, July 31, 2008, 8:08 PM
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > Dear Dimos,
> > > > > >
> > > > > > The Boiler and ovens will operate on different schedules with
> > > > > > different loads and will have different part load
efficiencies.
> > > > > > Therefore, I think you should model them separately, not as a
> > > combined
> > > > > > object.
> > > > > >
> > > > > > I have not modeled ovens before in E+, but I have applied
> them in
> > > > > > buildings. A typical oven will lose heat to the zone it
occupies
> > > > > > through the oven walls, so you'll need to know the insulation
> > > value of
> > > > > > those walls and calculate that rate. The rate will vary as the
> > oven
> > > > > > warms up and cools down, so you will need to know the
operating
> > > > > schedule.
> > > > > >
> > > > > > An oven also loses heat through the stack. That is the amount
> > which
> > > > > > should be assigned to the "Fraction Lost" field.
> > > > > >
> > > > > > --- In EnergyPlus_Support@ yahoogroups. com, D T
> > <ellinas.1984@ ...>
> > > > > wrote:
> > > > > > >
> > > > > > > Thanks for the help. I now understand why I'm not getting
> > values.
> > > > > > However, my ultimate goal is to obtain monthly gas usage
> > values for
> > > > > > one boiler and 4 ovens for the facility I am modeling.
Since I'm
> > > > > > trying to model a boiler and 4 ovens, could I just simply
> > > specify the
> > > > > > total power input from the boiler and ovens (in watts) under
> > the GAS
> > > > > > EQUIPMENT object? When I did that, I got an error in my
> > > simulation. Or
> > > > > > do I need to use the boiler object and something else for the
> > ovens?
> > > > > > I'm still struggling with trying to get gas usage values for
> > > this part
> > > > > > of my work. Any help or suggestions would be appreciated.
> > > > > > >
> > > > > > > Thank you,
> > > > > > > Dimos
> > > > > > >
> > > > > > > --- On Mon, 7/28/08, JV Dirkes II <jvd2pe@> wrote:
> > > > > > >
> > > > > > > From: JV Dirkes II <jvd2pe@>
> > > > > > > Subject: [EnergyPlus_ Support] Re: need help w/ monthly gas
> > usage
> > > > > results
> > > > > > > To: EnergyPlus_Support@ yahoogroups. com
> > > > > > > Date: Monday, July 28, 2008, 12:48 PM
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Dear Dimos,
> > > > > > >
> > > > > > > I took a look at your file and I think your problem is this:
> > > > > > >
> > > > > > > 1) You have an ELECTRIC heating coil in the furnace.
> > > > > > > 2) Since the Furnace is the only heating object, and its
> > coil uses
> > > > > > > electricity, there is no load for the Boiler:Steam.
> > > > > > > 3) Therefore, there is no gas consumption.
> > > > > > >
> > > > > > > --- In EnergyPlus_Support@ yahoogroups. com, "ellinas.1984"
> > > > > > > <ellinas.1984@ ...> wrote:
> > > > > > > >
> > > > > > > > Hello group,
> > > > > > > > The facility I am modeling has two boilers. I specified
> one of
> > > > them
> > > > > > > > under the boiler object in EnergyPlus just to see how it
> would
> > > > > run. I
> > > > > > > > also specified the gas rate schedule. However, when I
> run the
> > > > > > > > simulation and view the results, I get values of zero
> for the
> > > > > monthly
> > > > > > > > gas usages. Unlike the results from the electricity rate
> > > schedule
> > > > > > that
> > > > > > > > I specified, where it shows the monthly usage in the
> results,
> > > > I get
> > > > > > > > nothing for the gas. Is there anyone out there that knows
> > how to
> > > > > help
> > > > > > > > me solve this problem?
> > > > > > > >
> > > > > > > > Thank you,
> > > > > > > > Dimos
> > > > > > > >
> > > > > > > > p.s. I uploaded my idf file. It is bakery3.idf with the
> > subtitle
> > > > > "gas
> > > > > > > > rate usage values" under the problem submittal folder.
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>
------------------------------------
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/EnergyPlus_Support/join
(Yahoo! ID required)
<*> To change settings via email:
mailto:EnergyPlus_Support-digest@xxxxxxxxxxxxxxx
mailto:EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx
<*> To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/