REFRIGERATION:SECONDARYSYSTEM
Works in conjunction with refrigerated cases and walkins to simulate the performance of a secondary loop supermarket refrigeration system. Heat from the refrigeration loads served by the secondary loop is absorbed by a primary refrigeration system (Refrigeration:System). The SecondarySystem object simulates a heat exchanger that is an evaporator, or refrigeration load, on the primary refrigeration system.
Name
Type: alphanumeric
Refrigerated Case or Walkin or CaseAndWalkInList Name
Type: list of objects
(
REFRIGERATION:CASE,
REFRIGERATION:CASEANDWALKINLIST,
REFRIGERATION:AIRCHILLER or
REFRIGERATION:WALKIN)
Enter the name of a Refrigeration:Case or Refrigeration:WalkIn object. If there is more than one refrigerated case or walk-in served by this secondary system, enter the name of a Refrigeration:CaseAndWalkInList object.
Circulating Fluid Type
Type: choice
(FluidAlwaysLiquid or FluidPhaseChange)
If "FluidAlwaysLiquid" is selected, the fluid properties must be input using the objects: FluidProperties:Name, FluidProperties:GlycolConcentration, and, if user defined fluid type, FluidProperties:Temperatures and FluidProperties:Concentration. Many sets of fluid properties can be found in GlycolPropertiesRefData.idf. If "FluidPhaseChange" is selected, the refrigerant properties must be input using the objects: (if user defined fluid type): FluidProperties:Name, FluidProperties:Temperatures, FluidProperties:Saturated, and FluidProperties:Superheated. Many sets of refrigerant data can be found in FluidPropertiesRefData.idf.
Circulating Fluid Name
Type: list of objects
( or
FLUIDPROPERTIES:GLYCOLCONCENTRATION)
This must correspond to a name in the FluidProperties:Name object.
Evaporator Capacity
Type: real number
For "FluidAlwaysLiquid", at least one of the two, Evaporator Capacity OR Evaporator Flow Rate for Secondary Fluid, is required. For "FluidPhaseChange", the default capacity is the sum of the rated capacities of the Cases and Walk-ins served by the secondary loop.
Unit: W
Minimum: 0.0
Evaporator Flow Rate for Secondary Fluid
Type: real number
For "FluidAlwaysLiquid", at least one of the two, Evaporator Capacity OR Evaporator Flow Rate for Secondary Fluid, is required. For "FluidPhaseChange" loops, this input is not used. (see PhaseChange Circulating Rate)
Unit: m3/s
Minimum: 0.0
Evaporator Evaporating Temperature
Type: real number
This is the evaporating temperature in the heat exchanger used to chill or condense the secondary loop circulating fluid. It is NOT the temperature in any cases or walk-ins served by the secondary loop.
Unit: C
Evaporator Approach Temperature Difference
Type: real number
For "FluidAlwaysLiquid", this is the rated difference between the temperature of the circulating fluid leaving the heat exchanger and the heat exchanger's rated evaporating temperature. For "FluidPhaseChange", this is the difference between the temperature of the evaporating and condensing temperatures in the heat exchanger.
Unit: deltaC
Evaporator Range Temperature Difference
Type: real number
For "FluidAlwaysLiquid", this is the rated difference between the temperature of the circulating fluid entering the heat exchanger and the temperature of the circulating fluid leaving the heat exchanger, and is Required. For "FluidPhaseChange", this input is not used.
Unit: deltaC
Number of Pumps in Loop
Type: integer
Default: 1
Total Pump Flow Rate
Type: real number
For "FluidAlwaysLiquid",if not input, Evaporator Flow Rate for Secondary Fluid will be used. For "FluidPhaseChange", if not input, this will be calculated using the PhaseChange Circulating Rate.
Unit: m3/s
Minimum: 0.0
Total Pump Power
Type: real number
Either the Total Pump Power or the Total Pump Head is required.
Unit: W
Minimum: 0.0
Total Pump Head
Type: real number
Either the Total Pump Power or the Total Pump Head is required.
Unit: Pa
Minimum: 0.0
PhaseChange Circulating Rate
Type: real number
This is the total mass flow at the pump divided by the gaseous mass flow leaving the refrigeration load.
Unit: dimensionless
Minimum: 1.0
Default: 2.5
Pump Drive Type
Type: choice
(Constant or Variable)
Default: Constant
Variable Speed Pump Cubic Curve Name
Type: list of objects
(
CURVE:LINEAR,
TABLE:LOOKUP,
CURVE:RECTANGULARHYPERBOLA1,
CURVE:SIGMOID,
CURVE:QUARTIC,
CURVE:CUBIC,
CURVE:EXPONENT,
CURVE:EXPONENTIALDECAY,
CURVE:DOUBLEEXPONENTIALDECAY,
CURVE:EXPONENTIALSKEWNORMAL,
CURVE:QUADRATIC,
CURVE:RECTANGULARHYPERBOLA2 or
CURVE:FUNCTIONAL:PRESSUREDROP)
Variable Speed Pump Curve Name is applicable to variable speed pumps only.
Pump Motor Heat to Fluid
Type: real number
This is the portion of the pump motor heat added to secondary circulating fluid and is equal to the motor efficiency for non-hermetic motor. Enter 1.0 for a semi-hermetic motor.
Unit: dimensionless
Minimum: 0.5
Maximum: 1.0
Default: 0.85
Sum UA Distribution Piping
Type: real number
Use only if you want to include distribution piping heat gain in refrigeration load.
Unit: W/K
Default: 0.0
Distribution Piping Zone Name
Type: list of objects
( or
ZONE)
This will be used to determine the temperature used for distribution piping heat gain. The pipe heat gains are also counted as cooling credit for the zone. Required only if Sum UA Distribution Piping >0.0
Sum UA Receiver/Separator Shell
Type: real number
Use only if you want to include Receiver/Separator Shell heat gain in refrigeration load.
Unit: W/K
Default: 0.0
Receiver/Separator Zone Name
Type: list of objects
( or
ZONE)
This will be used to determine the temperature used for Receiver/Separator Shell heat gain. The shell heat gains are also counted as cooling credit for the zone. Required only if Sum UA Receiver/Separator Shell >0.0
Evaporator Refrigerant Inventory
Type: real number
This value refers to the refrigerant circulating within the primary system providing cooling to the chiller for the secondary loop, not to the fluid circulating within the secondary loop itself.
Unit: kg
Default: 0.0
End-Use Subcategory
Type: alphanumeric
Any text may be used here to categorize the end-uses in the ABUPS End Uses by Subcategory table.
Default: General