HeatUtility#

HeatUtility objects take care of finding utility requirements.

class HeatUtility(heat_transfer_efficiency=None, unit=None, hxn_ok=False)[source]#

Create an HeatUtility object that can choose a utility stream and calculate utility requirements. It can calculate required flow rate, temperature change, or phase change of utility. Calculations assume counter current flow rate.

Parameters:

heat_transfer_efficiency (float, optional) – Enforced fraction of heat transferred from utility (due to losses to environment).
unit (Unit, optional) – Parent unit using this heat utility.
hxn_ok (bool, optional) – Whether heat utility can be satisfied within a heat exchanger network.

Examples

Create a heat utility:

>>> from biosteam import HeatUtility
>>> hu = HeatUtility()
>>> hu.show()
HeatUtility: None
 duty: 0
 flow: 0
 cost: 0

Calculate utility requirement by calling it with a duty (kJ/hr), and entrance and exit temperature (K):

>>> hu(1000, 300, 350)
>>> hu.show()
HeatUtility: low_pressure_steam
 duty: 1.05e+03 kJ/hr
 flow: 0.0272 kmol/hr
 cost: 0.00647 USD/hr

All results are accessible:

>>> hu.ID, hu.duty, hu.flow, hu.cost
('low_pressure_steam', 1052.6315789473686, 0.02721274387089031, 0.006471190492497716)

All results are accessible:

>>> hu.ID, hu.duty, hu.flow, hu.cost
('low_pressure_steam', 1052.6315789473686, 0.02721274387089031, 0.006471190492497716)

dT: float = 5#: Minimum approach temperature difference. Used to assign the pinch temperature of the utility stream.

display_units: Display:py:class:`~biosteam.Unit`s = DisplayUnits(duty='kJ/hr', flow='kmol/hr', cost='USD/hr')#: Units of measure for IPython display.

thermo_water: Thermo = Thermo(chemicals=CompiledChemicals([Water]), mixture=IdealMixture(..., include_excess_energies=False), Gamma=DortmundActivityCoefficients, Phi=IdealFugacityCoefficients, PCF=MockPoyintingCorrectionFactors)#: Used broadly throughout utilities.

thermo_propane: Thermo = Thermo(chemicals=CompiledChemicals([Propane]), mixture=IdealMixture(..., include_excess_energies=False), Gamma=DortmundActivityCoefficients, Phi=IdealFugacityCoefficients, PCF=MockPoyintingCorrectionFactors)#: Used for refrigeration utility.

thermo_propylene: Thermo = Thermo(chemicals=CompiledChemicals([Propylene]), mixture=IdealMixture(..., include_excess_energies=False), Gamma=DortmundActivityCoefficients, Phi=IdealFugacityCoefficients, PCF=MockPoyintingCorrectionFactors)#: Used for refrigeration utility.

thermo_ethylene: Thermo = Thermo(chemicals=CompiledChemicals([Ethylene]), mixture=IdealMixture(..., include_excess_energies=False), Gamma=DortmundActivityCoefficients, Phi=IdealFugacityCoefficients, PCF=MockPoyintingCorrectionFactors)#: Used for refrigeration utility.

thermo_natural_gas: Thermo = Thermo(chemicals=CompiledChemicals([Methane, N2, CO2, O2, H2O]), mixture=IdealMixture(..., include_excess_energies=False), Gamma=DortmundActivityCoefficients, Phi=IdealFugacityCoefficients, PCF=MockPoyintingCorrectionFactors)#: Used exclusively for furnaces.

characterization_factors: dict[tuple[str, str], tuple[float, Absolute:py:class:`~biosteam.Unit`sOfMeasure]] = {}#: Characterization factor data (value and units) by agent ID and impact key.

cooling_agents: list[UtilityAgent] = [<UtilityAgent: cooling_water>, <UtilityAgent: chilled_water>, <UtilityAgent: chilled_brine>, <UtilityAgent: propane>, <UtilityAgent: propylene>, <UtilityAgent: ethylene>]#: All cooling utilities available.

heating_agents: list[UtilityAgent] = [<UtilityAgent: low_pressure_steam>, <UtilityAgent: medium_pressure_steam>, <UtilityAgent: high_pressure_steam>, <UtilityAgent: natural_gas>]#: All heating utilities available.

classmethod set_CF(ID, key, value, basis=None, units=None)[source]#

Set the characterization factor of a utility agent for a given impact key.

Parameters:

ID (str) – ID of utility agent.
key (str) – Key of impact indicator.
value (float) – Characterization factor value.
basis (str, optional) – Basis of characterization factor. Valid dimensions include weight, molar, and energy (e.g. ‘kg’, ‘kmol’, ‘kJ’). Defaults to ‘kg’.
units (str, optional) – Units of impact indicator. Before using this argument, the default units of the impact indicator should be defined with settings.define_impact_indicator. Units must also be dimensionally consistent with the default units.

Raises:

ValueError – When the duty characterization factor for a cooling agent is positive (should be negative).
DimensionError – When characterization factor is not given in dimensions of weight, molar, or energy.