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Re: [EnergyPlus_Support] Economics and Demand Cost Calculations



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
> 
> 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
> 
> 
> 
> 
> 






The primary EnergyPlus web site is found at:
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The group web site is:
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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.
 
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