Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
The Source Variable under UtilityCost:Charge:Simple is what EnergyPlus multiplies by the cost to give you the cost for that block of time. Right now you example is saying "Multiply the peakDemand for that month by $4.1" which is why you're getting a varied rate. You want to multiply 4.10 by the Ratchet'd demand so you need to change the source variable to 12MonthDemandPeak (Honestly I'd change the name of the ratchet to something different for less confusion). Here is a quick example:
UtilityCost:Ratchet,
Ratchet1, !- Name
UtilityTarrif, !- Tariff Name
totalDemand, !- Baseline Source Variable
totalDemand, !- Adjustment Source Variable
Annual, !- Season From
Annual, !- Season To
1; !- Multiplier Value or Variable Name
UtilityCost:Charge:Simple,
Demand, !- Utility Cost Charge Simple Name
UtilityTarrif, !- Tariff Name
Ratchet1, !- Source Variable
Annual, !- Season
DemandCharges, !- Category Variable Name
4.1; !- Cost per Unit Value or Variable Name
| | 2 | No.2 Revision |
The Source Variable under UtilityCost:Charge:Simple is what EnergyPlus multiplies by the cost to give you the cost for that block of time. Right now you example is saying "Multiply the peakDemand for that month by $4.1" $4.1 oh and also calculate the ratchet but don't do anything with it" which is why you're getting a varied rate. You want to multiply 4.10 by the Ratchet'd demand so you need to change the source variable to 12MonthDemandPeak (Honestly I'd change the name of the ratchet to something different for less confusion). Here is a quick example:
UtilityCost:Ratchet,
Ratchet1, !- Name
UtilityTarrif, !- Tariff Name
totalDemand, !- Baseline Source Variable
totalDemand, !- Adjustment Source Variable
Annual, !- Season From
Annual, !- Season To
1; !- Multiplier Value or Variable Name
UtilityCost:Charge:Simple,
Demand, !- Utility Cost Charge Simple Name
UtilityTarrif, !- Tariff Name
Ratchet1, !- Source Variable
Annual, !- Season
DemandCharges, !- Category Variable Name
4.1; !- Cost per Unit Value or Variable Name
| | 3 | No.3 Revision |
The Source Variable under UtilityCost:Charge:Simple is what EnergyPlus multiplies by the cost to give you the cost for that block of time. Right now you your example is saying "Multiply the peakDemand for that month by $4.1 oh and also calculate the ratchet but don't do anything with it" which is why you're getting a varied rate. You want to multiply 4.10 by the Ratchet'd demand so you need to change the source variable to 12MonthDemandPeak (Honestly I'd change the name of the ratchet to something different for less confusion). Here is a quick example:
UtilityCost:Ratchet,
Ratchet1, !- Name
UtilityTarrif, !- Tariff Name
totalDemand, !- Baseline Source Variable
totalDemand, !- Adjustment Source Variable
Annual, !- Season From
Annual, !- Season To
1; !- Multiplier Value or Variable Name
UtilityCost:Charge:Simple,
Demand, !- Utility Cost Charge Simple Name
UtilityTarrif, !- Tariff Name
Ratchet1, !- Source Variable
Annual, !- Season
DemandCharges, !- Category Variable Name
4.1; !- Cost per Unit Value or Variable Name
| | 4 | No.4 Revision |
The Source Variable under UtilityCost:Charge:Simple is what EnergyPlus multiplies by the cost to give you the cost for that block of time. Right now your example is saying "Multiply the peakDemand for that month by $4.1 oh and also calculate the ratchet but don't do anything with it" which is why you're getting a varied rate. You want to multiply 4.10 by the Ratchet'd demand so you need to change the source variable to 12MonthDemandPeak (Honestly I'd change the name of the ratchet to something different for less confusion). Here is a quick example:
UtilityCost:Ratchet,
Ratchet1, !- Name
UtilityTarrif, !- Tariff Name
totalDemand, !- Baseline Source Variable
totalDemand, !- Adjustment Source Variable
Annual, !- Season From
Annual, !- Season To
1; !- Multiplier Value or Variable Name
UtilityCost:Charge:Simple,
Demand, !- Utility Cost Charge Simple Name
UtilityTarrif, !- Tariff Name
Ratchet1, !- Source Variable
Annual, !- Season
DemandCharges, !- Category Variable Name
4.1; !- Cost per Unit Value or Variable Name
To answer your second question. The utility costs are calculated after the simulation is completed. So if the peak demand is in July, the ratchet cost in January will use the July peak demand.
