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[EnergyPlus_Support] Re: Economics and Demand Cost Calculations
Thank you!
-Greg
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Griffith, Brent" <brent_griffith@...> wrote:
>
> A formal methodology for splitting demand charges across end uses was
> prepared as part of the commercial building tax credits. See section
> 3.1 of the report at:
>
>
>
> http://www.nrel.gov/docs/fy07osti/40228.pdf
>
>
>
> These calculations are not supported inside EnergyPlus; you would have
> to do them with postprocessing.
>
>
>
> Input objects like the following can be used to report out the
> components of demand at the time they occur.
>
>
>
> Report:Table:Monthly,
>
> Components of Peak Electrical Demand, !- Name
>
> 3, !- DigitsAfterDecimal
>
> Electricity:Facility, !- VariableOrMeterName01
>
> Maximum, !- AggregationType01
>
> InteriorLights:Electricity, !- VariableOrMeterName02
>
> ValueWhenMaxMin, !- AggregationType02
>
> InteriorEquipment:Electricity, !- VariableOrMeterName03
>
> ValueWhenMaxMin, !- AggregationType03
>
> Fans:Electricity, !- VariableOrMeterName04
>
> ValueWhenMaxMin, !- AggregationType04
>
> Heating:Electricity, !- VariableOrMeterName05
>
> ValueWhenMaxMin, !- AggregationType05
>
> Cooling:Electricity, !- VariableOrMeterName06
>
> ValueWhenMaxMin; !- AggregationType06
>
>
>
>
>
> ________________________________
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of boulder1259
> Sent: Friday, August 17, 2007 4:22 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: Economics and Demand Cost Calculations
>
>
>
> What I am trying to do is figure out what portion of the utility bill is
> due to lighting,
> HVAC, process, etc. (a common question from clients). The billing is
> simple: demand and
> consumption charges. Since demand charges are by far the largest part of
> the bill, I
> wanted an easy way to split these charges amongst the various services.
> If I understand
> you correctly, this isn't possible with the current version of
> EnergyPlus.
>
> Most of what you said about submetered charges not adding up to the
> facility metered
> charges makes complete sense. My mistake was that I wasn't thinking
> about the
> submeters as being actual meters. Any time demand charges are involved,
> I would expect
> the sum of the submeters and facility meter to differ because the demand
> peaks on the
> various meters are not likely not be coincident. Only if they were would
> I expect the two
> to be the same.
>
> Thanks,
> Greg
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com> , "Michael J. Witte"
> <mjwitte@> wrote:
> >
> > I am not sure I understand what you are trying to do. The energy and
> demand
> > charges within a given tariff will only be based on the specific meter
> or sub-
> > meter that is assigned to that tariff. If you want to calculate demand
> charges
> > for the building as a whole but then separate energy charges by
> end-use, you
> > would need a tariff connected to the facility electricity meter that
> calculates
> > only demand charges, and then tariffs connected to submeters that only
>
> > calcaulate energy charges.
> >
> > Ultimately, I have to question your assumption that the submetered
> costs will
> > add up to the same value as the facility meter costs. This will only
> be true
> > if the rates are a very simple single charge for energy and for
> demand, say
> > $0.10/kWh for energy and $15.00/kW for demand. If there are any sort
> of
> > declining blocks or ratchets or other complexities to the rate
> structure, they
> > will not total to the same value. The use of separate tariff objects
> in
> > EnergyPlus is intended to be used when the building truly has meters
> which are
> > separately billed, such as a separate meter for space-heating
> electricity.
> >
> > Mike
> >
> >
> > On 13 Aug 2007 at 18:31, boulder1259 wrote:
> >
> > > I'm trying to figure out a way to apportion various building service
> costs but
> > > am not having much luck.
> > >
> > > When I sent up a tariff for facility-wide electricity charges (the
> charges
> > > include demand charges), EnergyPlus seems to produce reasonable
> values.
> > > However, if I try to do the same for the various building services
> and then sum
> > > them, the sum of the charges does not match the value of when I look
> at the
> > > building as a whole.
> > >
> > > I'm seeing that the electricity consumption charges can be summed,
> but that the
> > > electricity demand charges cannot. Apparently, the demand charges
> for the
> > > individual services (e.g., lighting) are not calculated from the
> facility's
> > > demand charges but rather independently.
> > >
> > > Do you have suggestions of how to split the electric bill into its
> various parts
> > > (e.g., lighting, pumps, fans, etc.)?
> > >
> > > Thanks,
> > > Greg
> > >
> > >
> > >
> > > The primary EnergyPlus web site is found at:
> > > http://www.energyplus.gov <http://www.energyplus.gov>
> > >
> > > The group web site is:
> > > http://groups.yahoo.com/group/EnergyPlus_Support/
> <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
> > >
> > >
> > >
> > >
> > >
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
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