Energy Recovery Device

This energy recovery device unit model represents a reversible pump or Pelton turbine. It is a class of pressure changer which is based on the IDAES pressure changer and makes the following assumptions:

• supports a single liquid phase only

• supports steady-state only

• supports isothermal pump only

Degrees of Freedom

Energy recovery device units generally have two degrees of freedom:

• outlet pressure, \(P_{out}\) or pressure change across the inlet and outlet,:math:Delta P

• energy recovery device efficiency

Model Structure

The energy recovery device unit model consists of a single ControlVolume0D (named control_volume) with one Inlet Port (named inlet) and one Outlet Port (named outlet). This model inherits IDAES pressure changer with the configuration compressor fixed to False, representing that the unit should be considered as an expander with pressure drop.

Sets

Description	Symbol	Indices
Time	\(t\)	[0]
Phases	\(p\)	[‘Liq’]
Components	\(j\)	[‘H2O’, ‘NaCl’]*

*Solute depends on the imported property model; example shown here is for the NaCl property model.

Variables

The variables are the same as those listed in the “Variable” tab of IDAES pressure changer.

Equations and Relationships

The constraints are the same as those listed in IDAES pressure changer.

Class Documentation

class watertap.unit_models.pressure_changer.EnergyRecoveryDevice(*args, **kwds)

Parameters:

• rule (function) – A rule function or None. Default rule calls build().

• concrete (bool) – If True, make this a toplevel model. Default - False.

• ctype (class) –

  Pyomo ctype of the block. Default - pyomo.environ.Block

  Config args

  dynamic

  Indicates whether this model will be dynamic or not, default = useDefault. Valid values: { useDefault - get flag from parent (default = False), True - set as a dynamic model, False - set as a steady-state model.}

  has_holdup

  Indicates whether holdup terms should be constructed or not. Must be True if dynamic = True, default - False. Valid values: { useDefault - get flag from parent (default = False), True - construct holdup terms, False - do not construct holdup terms}

  material_balance_type

  Indicates what type of mass balance should be constructed, default - MaterialBalanceType.useDefault. Valid values: { MaterialBalanceType.useDefault - refer to property package for default balance type **MaterialBalanceType.none - exclude material balances, MaterialBalanceType.componentPhase - use phase component balances, MaterialBalanceType.componentTotal - use total component balances, MaterialBalanceType.elementTotal - use total element balances, MaterialBalanceType.total - use total material balance.}

  energy_balance_type

  Indicates what type of energy balance should be constructed, default - EnergyBalanceType.useDefault. Valid values: { EnergyBalanceType.useDefault - refer to property package for default balance type **EnergyBalanceType.none - exclude energy balances, EnergyBalanceType.enthalpyTotal - single enthalpy balance for material, EnergyBalanceType.enthalpyPhase - enthalpy balances for each phase, EnergyBalanceType.energyTotal - single energy balance for material, EnergyBalanceType.energyPhase - energy balances for each phase.}

  momentum_balance_type

  Indicates what type of momentum balance should be constructed, default - MomentumBalanceType.pressureTotal. Valid values: { MomentumBalanceType.none - exclude momentum balances, MomentumBalanceType.pressureTotal - single pressure balance for material, MomentumBalanceType.pressurePhase - pressure balances for each phase, MomentumBalanceType.momentumTotal - single momentum balance for material, MomentumBalanceType.momentumPhase - momentum balances for each phase.}

  has_phase_equilibrium

  Indicates whether terms for phase equilibrium should be constructed, default = False. Valid values: { True - include phase equilibrium terms False - exclude phase equilibrium terms.}

  compressor

  Indicates whether this unit should be considered a compressor (True (default), pressure increase) or an expander (False, pressure decrease).

  thermodynamic_assumption

  Flag to set the thermodynamic assumption to use for the unit. - ThermodynamicAssumption.isothermal (default) - ThermodynamicAssumption.isentropic - ThermodynamicAssumption.pump - ThermodynamicAssumption.adiabatic

  property_package

  Property parameter object used to define property calculations, default - useDefault. Valid values: { useDefault - use default package from parent model or flowsheet, PropertyParameterObject - a PropertyParameterBlock object.}

  property_package_args

  A ConfigBlock with arguments to be passed to a property block(s) and used when constructing these, default - None. Valid values: { see property package for documentation.}

  support_isentropic_performance_curves

  Include a block for performance curves, configure via isentropic_performance_curves.

  isentropic_performance_curves

  Configuration dictionary for the performance curve block.

  isentropic_performance_curves

  build_callback

  Optional callback to add performance curve constraints

  build_head_expressions

  If true add expressions for ‘head’ and ‘head_isentropic’. These expressions can be used in performance curve constraints.

  variable_efficiency

  Indicates the relationship used to define pump efficiency VariableEfficiency.none - uses default pump efficiency at BEP VariableEfficiency.flow - uses an efficiency correlation scaled to the BEP flow rate VariableEfficiency.flow_head - uses an efficiency correlation scaled to the BEP flow rate and head

• initialize (dict) – ProcessBlockData config for individual elements. Keys are BlockData indexes and values are dictionaries with config arguments as keys.

• idx_map (function) – Function to take the index of a BlockData element and return the index in the initialize dict from which to read arguments. This can be provided to override the default behavior of matching the BlockData index exactly to the index in initialize.

Returns:

(EnergyRecoveryDevice) New instance