Heat Exchanging

QSDsan: Quantitative Sustainable Design for sanitation and resource recovery systems

This module is developed by:

Part of this module is based on the biosteam package: https://github.com/BioSTEAMDevelopmentGroup/biosteam

This module is under the University of Illinois/NCSA Open Source License. Please refer to https://github.com/QSD-Group/QSDsan/blob/main/LICENSE.txt for license details.

class qsdsan.sanunits._heat_exchanging.HXprocess(ID='', ins: Sequence[AbstractStream] | None = None, outs: Sequence[AbstractStream] | None = (), thermo=None, init_with='Stream', F_BM_default=None, *, U=None, dT=5.0, T_lim0=None, T_lim1=None, material='Carbon steel/carbon steel', heat_exchanger_type='Floating head', N_shells=2, ft=None, phase0=None, phase1=None, H_lim0=None, H_lim1=None, inner_fluid_pressure_drop=None, outer_fluid_pressure_drop=None, neglect_pressure_drop=True)

Similar to biosteam.units.HXprocess, but can be initialized with qsdsan.SanStream and qsdsan.WasteStream.

See also

biosteam.units.HXprocess

H_lim0

[float] Temperature limit of outlet stream at index 0.

H_lim1

[float] Temperature limit of outlet stream at index 1.

N_shells

Number of shells for LMTD correction factor method.

T_lim0

[float] Temperature limit of outlet stream at index 0.

T_lim1

[float] Temperature limit of outlet stream at index 1.

U

[float] Enforced overall heat transfer coefficient (kW/m^2/K)

dT

[float] Pinch temperature difference.

ft

User imposed correction factor.

inner_fluid_pressure_drop

Optional[float] Pressure drop along the inner fluid.

line: str = 'Heat exchanger'

class-attribute Name denoting the type of Unit class. Defaults to the class name of the first child class

neglect_pressure_drop

[bool] Whether to assume a negligible pressure drop.

outer_fluid_pressure_drop

Optional[float] Pressure drop along the outer fluid.

phase0

Enforced phase of outlet at index 0

phase1

Enforced phase of outlet at index 1

total_heat_transfer

[float] Total heat transferred in kW (not including losses).

class qsdsan.sanunits._heat_exchanging.HXutility(ID='', ins: Sequence[AbstractStream] | None = None, outs: Sequence[AbstractStream] | None = (), thermo=None, init_with='Stream', F_BM_default=None, include_construction=True, T=None, V=None, rigorous=False, U=None, H=None, heat_exchanger_type='Floating head', material='Carbon steel/carbon steel', N_shells=2, ft=None, heat_only=None, cool_only=None, heat_transfer_efficiency=None, inner_fluid_pressure_drop=None, outer_fluid_pressure_drop=None, neglect_pressure_drop=True)

Similar to biosteam.units.HXutility, but can be initialized with qsdsan.SanStream and qsdsan.WasteStream and calculate material usage based on [1].

References

See also

biosteam.units.HXutility

H

[float] Enthalpy of outlet stream.

N_shells

Number of shells for LMTD correction factor method.

T

[float] Temperature of outlet stream (K).

U

[float] Enforced overall heat transfer coefficient (kW/m^2/K)

V

[float] Vapor fraction of outlet stream.

cool_only

[bool] If True, heat exchanger can only cool.

ft

User imposed correction factor.

heat_only

[bool] If True, heat exchanger can only heat.

heat_transfer_efficiency

[bool] User enforced heat transfer efficiency. A value less than 1 means that a fraction of heat transferred is lost to the environment. If value is None, it defaults to the heat transfer efficiency of the heat utility.

inner_fluid_pressure_drop

Optional[float] Pressure drop along the inner fluid.

line: str = 'Heat exchanger'

class-attribute Name denoting the type of Unit class. Defaults to the class name of the first child class

neglect_pressure_drop

[bool] Whether to assume a negligible pressure drop.

outer_fluid_pressure_drop

Optional[float] Pressure drop along the outer fluid.

rigorous

[bool] If true, calculate vapor liquid equilibrium

class qsdsan.sanunits._heat_exchanging.HeatExchangerNetwork(ID='', T_min_app=5.0, units=None, ignored=None, Qmin=0.001, force_ideal_thermo=False, cache_network=False, avoid_recycle=False, acceptable_energy_balance_error=None, replace_unit_heat_utilities=False)

Similar to the biosteam.units.facilities.HeatExchangerNetwork, but also a subclass of qsdsan.SanUnit

Examples

>>> import qsdsan as qs
>>> from qsdsan import Stream, sanunits as su
>>> from qsdsan.utils import create_example_components
>>> qs.set_thermo(create_example_components())
>>> salt_water = Stream('salt_water', Water=2000, NaCl=50, units='kg/hr')
>>> methanol = Stream('methanol', Methanol=20, units='kg/hr')
>>> ethanol = Stream('ethanol', Ethanol=10, units='kg/hr')
>>> M1 = su.MixTank('M1', ins=(salt_water, 'recycled_brine', methanol, ethanol), init_with='Stream')
>>> P1 = su.Pump('P1', ins=M1-0, init_with='Stream')
>>> H1 = su.HXutility('H1', ins=P1-0, T=350, init_with='Stream')
>>> S1 = su.ComponentSplitter('S1', ins=H1-0, split_keys=('Methanol', 'Ethanol'), init_with='Stream')
>>> M2 = su.Mixer('M2', ins=(S1-0, S1-1), outs='alcohols', init_with='Stream')
>>> S2 = su.Splitter('S2', ins=S1-2, outs=(1-M1, 'waste_brine'), split=0.2, init_with='Stream')
>>> H2 = su.HXutility('H2', ins=S2.outs[1], T=280, init_with='Stream')
>>> HXN = su.HeatExchangerNetwork('HXN')
>>> sys = qs.System('sys', path=(M1, P1, H1, S1, M2, S2, H2), facilities=(HXN,))
>>> sys.simulate()
>>> # The actual utility usage is just 30% of the original one (i.e., without HXN)
>>> round(HXN.actual_heat_util_load/HXN.original_heat_util_load, 2)
0.28
>>> HXN.stream_life_cycles 
[<StreamLifeCycle: Stream_0, cold
    life_cycle = [
            <LifeStage: <HXprocess: HX_0_1_hs>, H_in = 0 kJ, H_out = 3.15e+05 kJ>
            <LifeStage: <HXutility: Util_0_hs>, H_in = 3.15e+05 kJ, H_out = 4.4e+05 kJ>
    ]>,
 <StreamLifeCycle: Stream_1, hot
    life_cycle = [
            <LifeStage: <HXprocess: HX_0_1_hs>, H_in = 3.49e+05 kJ, H_out = 3.36e+04 kJ>
            <LifeStage: <HXutility: Util_1_cs>, H_in = 3.36e+04 kJ, H_out = -1.22e+05 kJ>
    ]>]

See also

biosteam.units.facilities.HeatExchangerNetwork

line: str = 'Heat exchanger network'

class-attribute Name denoting the type of Unit class. Defaults to the class name of the first child class