Chiller:Electric:EIR
Used in:
- Chilled water loop, supply side
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Used in:
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Chillers provide chilled water to cooling coils, chilled beams and cooled ceilings. Chiller components are used in both Compact and Detailed HVAC:
When using Detailed HVAC, to edit an existing chiller go to the Cold water supply loop (HVAC System > Cold water loop > Supply loop) level where the chiller is placed, click on the chiller icon to highlight it then either right click and select the Edit selected component menu option or, when using Learning mode, click on the Edit icon in at the top of the info panel.
The EnergyPlus Chiller:Electric:EIR model is used internally to represent all chillers in DesignBuilder.This chiller model is the empirical model used in the DOE-2.1 building energy simulation program. It uses performance information at reference conditions along with three curve fits for cooling capacity and efficiency to determine chiller operation at off-reference conditions. Chiller performance curves can be generated by fitting manufacturer’s catalog data or measured data. Performance curves for more than 160 chillers, including the default DOE-2.1E reciprocating and centrifugal chillers, are provided as templates for selection within the chiller dialog. This data comes from in the EnergyPlus Reference DataSets (Chillers.idf and AllDataSets.idf).
Note: Chiller:Electric:EIR objects and their associated performance curve objects are developed using performance information for a specific chiller and should normally be used together for an EnergyPlus simulation. Changing the object input values, or swapping performance curves between chillers, should be done with caution.
The auto-generated name of the chiller can be edited.
Use this browse option to select a chiller from the EnergyPlus chiller database.
This numeric field contains the reference cooling capacity of the chiller (in W or Btu/h). This should be the capacity of the chiller at the reference temperatures and water flow rates defined below. Alternately, this field can be autosized.
This numeric field contains the chiller’s coefficient of performance which is multiplied by the output of the chiller performance curves described below. This value should not include energy use due to pumps, evap-cooled or air-cooled condenser fans, or cooling tower fans. This COP should be at the reference temperatures and water flow rates defined below.
This numeric input represents the fraction of compressor electrical energy consumption that must be rejected by the condenser. Enter a value of 1.0 when modelling hermetic chillers. This value must be between 0.0 and 1.0, with a default value of 1.0.
This field determines if the chiller is modelled with constant or variable water flow through the evaporator. Valid choices are:
This numeric field allows you to specify a sizing factor for this component. The sizing factor is used when the component design inputs are autosized: the autosizing calculations are performed as usual and the results are multiplied by the sizing factor. For this component the inputs that would be altered by the sizing factor are: Reference capacity, Reference chilled water flow rate and Reference condenser water flow rate. Sizing factor allows the user to size a component to meet part of the design load while continuing to use the autosizing feature.
The condenser type determines what type of condenser will be included with this chiller. Valid condenser types are:
The default is 2-Water cooled which requires the full specification of the Condenser loop and its associated equipment. 1-Air cooled and 3-Evaporatively cooled do not require a Condenser loop to be specified.
This data is used to model condenser fan power associated with air-cooled or evaporatively cooled condensers. Enter the ratio of the condenser fan power to the reference chiller cooling capacity in W/W.
During the simulation the condenser fan power for air-cooled or evaporatively cooled chillers is calculated as total chiller power consumption multiplied by this ratio.
This numeric field contains the chiller’s reference leaving chilled water temperature (in °C or °F). The default value is 6.67°C.
This numeric field contains the chiller’s reference entering condenser fluid temperature (in °C or °F). The default value is 29.4°C. For water-cooled chillers this is the water temperature entering the condenser (e.g., leaving the cooling tower). For air- or evap-cooled condensers this is the entering outdoor air dry-bulb or wet-bulb temperature, respectively.
This numeric field contains the lower limit for the leaving chilled water temperature (in °C or °F). This temperature acts as a cut off for heat transfer in the evaporator, so that the fluid doesn’t get too cold. This input field is currently unused. The default value is 2˚C.
For a variable flow chiller this is the maximum water flow rate and for a constant flow chiller this is the operating water flow rate through the chiller’s evaporator. The units are (in m3/s or gal/min). This numeric input field must be greater than zero, or it can be autosized.
This numeric field contains the chiller’s operating condenser water flow rate (in m3/s or gal/min). This field can be autosized.
The name of a Bi-quadratic performance curve that parameterizes the variation of the cooling capacity as a function of the leaving chilled water temperature and the entering condenser fluid temperature. The output of this curve is multiplied by the reference capacity to give the cooling capacity at specific temperature operating conditions (i.e., at temperatures different from the reference temperatures). The curve should have a value of 1.0 at the reference temperatures and flow rates specified above. The bi-quadratic curve should be valid for the range of water temperatures anticipated for the simulation.
The name of a Bi-quadratic performance curve that parameterizes the variation of the energy input to cooling output ratio (EIR) as a function of the leaving chilled water temperature and the entering condenser fluid temperature. The EIR is the inverse of the COP. The output of this curve is multiplied by the reference EIR (inverse of the reference COP) to give the EIR at specific temperature operating conditions (i.e., at temperatures different from the reference temperatures). The curve should have a value of 1.0 at the reference temperatures and flow rates specified above. The bi-quadratic curve should be valid for the range of water temperatures anticipated for the simulation.
The name of a Quadratic performance curve that parameterizes the variation of the energy input ratio (EIR) as a function of the part-load ratio. The EIR is the inverse of the COP, and the part-load ratio is the actual cooling load divided by the chiller’s available cooling capacity. The output of this curve is multiplied by the reference EIR (inverse of the reference COP) and the Energy input to cooling output ratio function of temperature curve to give the EIR at the specific temperatures and part-load ratio at which the chiller is operating. This curve should have a value of 1.0 when the part-load ratio equals 1.0. The quadratic curve should be valid for the range of part-load ratios anticipated for the simulation.
This numeric field contains the chiller’s minimum part-load ratio. The expected range is between 0 and 1. Below this part-load ratio, the compressor cycles on and off to meet the cooling load. The Minimum part load ratio must be less than or equal to the Maximum part load ratio. The default value is 0.1.
This numeric field contains the chiller’s maximum part-load ratio. This value may exceed 1, but the normal range is between 0 and 1.0. The Maximum part load ratio must be greater than or equal to the Minimum part load ratio. The default value is 1.0.
This numeric field contains the chiller’s optimum part-load ratio. This is the part-load ratio at which the chiller performs at its maximum COP. The optimum part-load ratio must be greater than or equal to the Minimum part load ratio, and less than or equal to the Maximum part load ratio. The default value is 1.0.
This numeric field contains the chiller’s minimum unloading ratio. The expected range is between 0 and 1. The minimum unloading ratio is where the chiller capacity can no longer be reduced by unloading and must be false loaded to meet smaller cooling loads. A typical false loading strategy is hot-gas bypass. The minimum unloading ratio must be greater than or equal to the Minimum part load ratio, and less than or equal to the Maximum part load ratio. The default value is 0.2.
Many output variable names are common across all chiller types. These generic chiller output names all begin with the word "Chiller". Certain chiller types have additional output variables which are specific to that type of chiller. Specific chiller output names begin with the chiller type, for example, "Gas Absorption Chiller Heating Energy [J]." Chiller energy use is added to the appropriate plant-level meters as a cooling end-use.
HVAC,Average,Chiller Electric Power [W]
HVAC,Sum,Chiller Electric Consumption [J]
Zone,Meter,Electricity:Plant [J]
Zone,Meter,Cooling:Electricity [J]
HVAC,Average,Chiller Evap Heat Trans Rate [W]
HVAC,Sum,Chiller Evap Heat Trans [J]
Zone,Meter,EnergyTransfer:Plant [J]
Zone,Meter,Chillers:EnergyTransfer [J]
HVAC,Average,Chiller Evap Water Inlet Temp [C]
HVAC,Average,Chiller Evap Water Outlet Temp [C]
HVAC,Average,Chiller Evap Water Mass Flow Rate [kg/s]
HVAC,Average,Chiller Cond Heat Trans Rate [W]
HVAC,Sum,Chiller Cond Heat Trans [J]
Zone,Meter,HeatRejection:EnergyTransfer [J]
HVAC,Average,Chiller COP [W/W]
The following output is applicable only for air-cooled or evap-cooled chillers:
HVAC,Average,Chiller Cond Air Inlet Temp [C]
The following outputs are applicable only for evap-cooled chillers:
HVAC,Average,Chiller Basin Heater Electric Power [W]
HVAC,Average,Chiller Basin Heater Electric Consumption [J]
The following three outputs are only available for water-cooled chillers:
HVAC,Average,Chiller Cond Water Inlet Temp [C]
HVAC,Average,Chiller Cond Water Outlet Temp [C]
HVAC,Average,Chiller Cond Water Mass Flow Rate [kg/s]
HVAC,Average,Chiller Shaft Power [W]
These outputs are the electric power input to the chiller. In the case of steam or fuel-powered chillers, this repesents the internal chiller pumps and other electric power consumption. Consumption is metered on Cooling:Electricity, Electricity:Plant, and Electricity:Facility.
These outputs are the evaporator heat transfer which is the cooling delivered by the chiller. Chiller Evap Heat Trans is metered on Chillers:EnergyTransfer, EnergyTransfer:Plant, and EnergyTransfer:Facility.
These outputs are the evaporator (chilled water) inlet and outlet temperatures and flow rate.
This output is the coefficient of performance for the chiller during cooling operation. It is calculated as the evaporator heat transfer rate (Chiller Evap Heat Trans Rate) divided by the “fuel” consumption rate by the chiller. For the constant COP and electric chillers, the “fuel” is electricity so the divisor is Chiller Electric Power [W]. For the absorption chiller, the “fuel” is steam so the divisor is Steam Consumption Rate [W].
For the engine driven chiller and combustion turbine chiller, the output variable is renamed as Chiller Fuel COP to clarify that the primary energy input to the chiller is a gaseous or liquid fuel (natural gas, diesel, gasoline, etc.). The divisor is the appropriate fuel consumption rate (Chiller [fuel type] Consumption Rate).
For the direct fired absorption chiller, this variable is renamed as Direct Fired Absorption Chiller Cooling Fuel COP and the divisor is Direct Fired Absorption Chiller Cooling Gas Consumption Rate.
Note that this variable is reported as zero when the chiller is not operating. When reported for frequencies longer than "detailed" (such as timestep, hourly, daily, monthly or environment), this output will only be meaningful when the chiller is operating for the entire reporting period. To determine an average COP for a longer time period, compute the COP based on total evaporator heat transfer divided by total electric or fuel input over the desired period.
This output is the operating part-load ratio of the indirect absorption chiller. This output may fall below the minimum part-load ratio specified in the input. For this case, the Chiller Cycling Fraction is used to further define the performance of the indirect absorption chiller.
This output is the fraction of the timestep the indirect absorption chiller operates. When the chiller operates above the minimum part-load ratio, a chiller cycling fraction of 1 is reported. When the chiller operates below the minimum part-load ratio, the chiller cycling fraction reports the fraction of the timestep the indirect absorption chiller operates.
These outputs are the condenser heat transfer which is the heat rejected from the chiller to either a condenser water loop or through an air-cooled condenser. Chiller Cond Heat Trans is metered on HeatRejection:EnergyTransfer, EnergyTransfer:Plant, and EnergyTransfer:Facility.
This output is the condenser (heat rejection) inlet temperature for air-cooled or evap-cooled chillers. For an air-cooled chiller, this output would be the dry-bulb temperature of the air entering the condenser coil. For an evap-cooled chiller, this output would be the wet-bulb temperature of the air entering the evaporatively-cooled condenser coil.
These outputs are the electric power input to the chiller’s basin heater (for evaporativelycooled condenser type). Consumption is metered on Chillers:Electricity, Electricity:Plant, and Electricity:Facility
These outputs are the condenser (heat rejection) inlet and outlet temperatures and flow rate for water-cooled chillers.
For engine-driven and turbine-driven chillers, these outputs are the shaft power produced by the prime mover and transferred to the chiller compressor.
For chillers with heat recovery, such as engine-driven chillers, these outputs are the components of recoverable energy available. For a given chiller type, one or more of the following components may be applicable: Lube (engine lubricant), Jacket (engine coolant), Exhaust (engine exhaust), and Total. Chiller Lube Heat Recovery, Chiller Jacket Heat Recovery, and Chiller Exhaust Heat Recovery are metered on HeatRecovery:EnergyTransfer, EnergyTransfer:Plant, and EnergyTransfer:Facility.
This is the exhaust temperature leaving an engine chiller.
These outputs are the heat recovery inlet and outlet temperatures and flow rate for chillers with heat recovery such as engine-driven and gas turbine chillers.
These outputs are the steam or fuel input for steam or fuel-fired chillers. Valid fuel types depend on the type of chiller. <FuelType> may be one of: Gas (natural gas), Steam, Propane, Diesel, Gasoline, FuelOil#1, and FuelOil#2. Consumption is metered on Cooling:<FuelType>, <FuelType>:Plant, and <FuelType>:Facility.
These reports are available only for Electric EIR Chillers.
These outputs are for the electric power consumption of the chiller condenser fan and are applicable to air- or evaporatively-cooled chillers. This output is also added to a report meter with Resource Type = Electricity, End Use Key = Chillers, Group Key = Plant (Ref. Report Meter).
This is the output of the curve object Cooling Capacity Function of Temperature Curve.
This is the output of the curve object Electric Input to Cooling Output Ratio Function of Temperature Curve.
This is the output of the curve object Electric Input to Cooling Output Ratio Function of Part Load Curve.
This output is the ratio of the evaporator heat transfer rate plus the false load heat transfer rate (if applicable) to the available chiller capacity. This value is used to determine ChillerEIRFPLR.
The cycling ratio is the amount of time the chiller operates during each simulation timestep. If the chiller part-load ratio falls below the minimum part-load ratio, the chiller cycles on and off to meet the cooling load.
These outputs are the heat transfer rate and total heat transfer due to false loading of the chiller. When the chiller part-load ratio is below the minimum unloading ratio, the chiller false loads (e.g. hot-gas bypass) to further reduce capacity. The false load heat transfer report variable is not metered.