Components

This section provides an overview on all available component classes, how to specify simple inputs to components, implement custom values in context of characteristic lines or maps, and give hints as to how to implement custom equations to existing components or create custom components yourself.

List of components

Below we have collected the different components available in tespy per module. In the tabs you can view the available parameters per component and relevant links to the underlying equations, the class documentation and example.

components

Component

Class documentation and example: Component

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

basics

CycleCloser

Class documentation and example: CycleCloser

Table of constraints

Parameter	Description	Method
pressure_equality_constraint	pressure equality constraint	variable_equality_structure_matrix
enthalpy_equality_constraint	enthalpy equality constraint	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
mass_deviation	absolute deviation of mass flow between inlet and outlet	mass_flow	None
fluid_deviation	norm of absolute deviation of fluid composition between inlet and outlet	None	None

Sink

Class documentation and example: Sink

Source

Class documentation and example: Source

SubsystemInterface

Class documentation and example: SubsystemInterface

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix
pressure_equality_constraint	pressure equality constraint	variable_equality_structure_matrix
enthalpy_equality_constraint	enthalpy equality constraint	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
num_inter	number of interfacing connections	None	None

combustion

CombustionChamber

Class documentation and example: CombustionChamber

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow balance over all inflows and outflows	mass_flow_func
reactor_pressure_constraints	pressure equality constraints	combustion_pressure_structure_matrix
stoichiometry_constraints	constraints for stoichiometry of the reaction	stoichiometry_func
energy_balance_constraints	constraint for energy balance	energy_balance_func

Table of parameters

Parameter	Description	Quantity	Method
lamb	available oxygen to stoichiometric oxygen ratio	ratio	lambda_func
ti	thermal input (fuel LHV multiplied with mass flow)	heat	ti_func

DiabaticCombustionChamber

Class documentation and example: DiabaticCombustionChamber

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow balance over all inflows and outflows	mass_flow_func
stoichiometry_constraints	constraints for stoichiometry of the reaction	stoichiometry_func

Table of parameters

Parameter	Description	Quantity	Method
lamb	available oxygen to stoichiometric oxygen ratio	ratio	lambda_func
ti	thermal input (fuel LHV multiplied with mass flow)	heat	ti_func
pr	outlet 0 to inlet 0 pressure ratio	ratio	pr_structure_matrix
dp	inlet 0 to outlet 0 absolute pressure change	pressure	dp_structure_matrix
eta	heat dissipation ratio relative to thermal input	efficiency	energy_balance_func
Qloss	heat dissipation	heat	None

CombustionEngine

Class documentation and example: CombustionEngine

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow balance over all inflows and outflows	mass_flow_func
reactor_pressure_constraints	pressure equality constraints	combustion_pressure_structure_matrix
stoichiometry_constraints	constraints for stoichiometry of the reaction	stoichiometry_func
energy_balance_constraints	constraint for energy balance	energy_balance_func
power_constraints	equation for thermal input to power generation relation	tiP_char_func
heat1_constraints	equation for thermal input to heating port 1 heat generation relation	Q1_char_func
heat2_constraints	equation for thermal input to heating port 2 heat generation relation	Q2_char_func
heatloss_constraints	equation for thermal input to heat dissipation relation	Qloss_char_func
mass_flow_cooling_constraints	equation for mass flow equality at heating ports	variable_equality_structure_matrix
fluid_cooling_constraints	equation for fluid composition equality at heating ports	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
lamb	available oxygen to stoichiometric oxygen ratio	ratio	lambda_func
ti	thermal input (fuel LHV multiplied with mass flow)	heat	ti_func
P [1]	mechanical power generated by the engine	power	None
Q1	heating port 1 heat production	heat	Q1_func
Q2	heating port 2 heat production	heat	Q2_func
Qloss [1]	heat dissipation	heat	None
pr1	heating port 1 outlet to inlet pressure ratio	ratio	pr_structure_matrix
pr2	heating port 2 outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp1	heating port 1 inlet to outlet absolute pressure change	pressure	dp_structure_matrix
dp2	heating port 2 inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta1	heating port 1 non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
zeta2	heating port 2 non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
eta_mech	None	None	None
T_v_inner	None	None	None

Table of characteristic lines and maps

Parameter	Description	Method
tiP_char	thermal input to power lookup table	None
Q1_char	thermal input to heat production of port 1 lookup table	None
Q2_char	thermal input to heat production of port 2 lookup table	None
Qloss_char	thermal input to heat dissipation lookup table	None

displacementmachinery

DisplacementMachine

Class documentation and example: DisplacementMachine

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
P	power input of the component	power	energy_balance_func
pr	outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix

PolynomialCompressor

Class documentation and example: PolynomialCompressor

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
P	power consumption	power	None
pr	outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
Q_diss	heat dissipation	heat	None
eta_vol	volumetric efficiency	efficiency	None
dissipation_ratio	heat dissipation ratio relative to power consumption	ratio	None
Q_diss_rel	heat dissipation ratio relative to power consumption(deprecated)	ratio	None
rpm [1]	compressor frequency	None	None
reference_state	reference state definition for the scaling of displacement with compressor rpm	None	None
eta_s_poly	polynomial coefficients for isentropic efficiency	None	None
eta_vol_poly	polynomial coefficients for volumetric efficiency	None	None
eta_s	isentropic efficiency	efficiency	None

Table of parameter groups

Parameter	Description	Required parameters	Method
eta_vol_poly_group	displacement equation based on polynomial coefficients for volumetric efficiency	reference_state, eta_vol_poly, rpm	eta_vol_poly_group_func
eta_vol_group	displacement equation based on fixed volumetric efficiency	reference_state, eta_vol, rpm	eta_vol_group_func
eta_s_poly_group	isentropic efficiency equation based on polynomial coefficients	eta_s_poly, dissipation_ratio	eta_s_poly_group_func
eta_s_group	isentropic efficiency equation with fixed efficiency	eta_s, dissipation_ratio	eta_s_group_func
energy_balance_group	energy balance equation for fixed power and dissipation ratio	P, dissipation_ratio	energy_balance_group_func

PolynomialCompressorWithCooling

Class documentation and example: PolynomialCompressorWithCooling

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix
cooling_energy_balance_constraints	energy balance for the cooling ports	cooling_energy_balance_func

Table of parameters

Parameter	Description	Quantity	Method
P	power consumption	power	None
pr	outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
Q_diss	heat dissipation	heat	None
eta_vol	volumetric efficiency	efficiency	None
dissipation_ratio	heat dissipation ratio relative to power consumption	ratio	None
Q_diss_rel	heat dissipation ratio relative to power consumption(deprecated)	ratio	None
rpm [1]	compressor frequency	None	None
reference_state	reference state definition for the scaling of displacement with compressor rpm	None	None
eta_s_poly	polynomial coefficients for isentropic efficiency	None	None
eta_vol_poly	polynomial coefficients for volumetric efficiency	None	None
eta_s	isentropic efficiency	efficiency	None
eta_recovery	share of dissipated heat usable in cooling port	efficiency	None
td_minimal	theoretical minimal temperature difference between working and cooling fluid	temperature_difference	None
dp_cooling	cooling port inlet to outlet absolute pressure change	pressure	dp_structure_matrix
pr_cooling	cooling port outlet to inlet pressure ratio	ratio	pr_structure_matrix

Table of parameter groups

Parameter	Description	Required parameters	Method
eta_vol_poly_group	displacement equation based on polynomial coefficients for volumetric efficiency	reference_state, eta_vol_poly, rpm	eta_vol_poly_group_func
eta_vol_group	displacement equation based on fixed volumetric efficiency	reference_state, eta_vol, rpm	eta_vol_group_func
eta_s_poly_group	isentropic efficiency equation based on polynomial coefficients	eta_s_poly, dissipation_ratio	eta_s_poly_group_func
eta_s_group	isentropic efficiency equation with fixed efficiency	eta_s, dissipation_ratio	eta_s_group_func
energy_balance_group	energy balance equation for fixed power and dissipation ratio	P, dissipation_ratio	energy_balance_group_func

heat_exchangers

HeatExchanger

Class documentation and example: HeatExchanger

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix
energy_balance_constraints	hot side to cold side heat transfer equation	energy_balance_func

Table of parameters

Parameter	Description	Quantity	Method
Q	heat transfer from hot side	heat	energy_balance_hot_func
kA	heat transfer coefficient considering terminal temperature differences	heat_transfer_coefficient	kA_func
td_log	logarithmic temperature difference	temperature_difference	None
ttd_u	terminal temperature difference at hot side inlet to cold side outlet	temperature_difference	ttd_u_func
ttd_l	terminal temperature difference at hot side outlet to cold side inlet	temperature_difference	ttd_l_func
ttd_min	minimum terminal temperature difference	temperature_difference	ttd_min_func
pr1	hot side outlet to inlet pressure ratio	ratio	pr_structure_matrix
pr2	cold side outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp1	hot side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
dp2	cold side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta1	hot side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
zeta2	cold side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
eff_cold	heat exchanger effectiveness for cold side	efficiency	eff_cold_func
eff_hot	heat exchanger effectiveness for hot side	efficiency	eff_hot_func
eff_max	maximum heat exchanger effectiveness	efficiency	eff_max_func

Table of parameter groups

Parameter	Description	Required parameters	Method
kA_char	equation for heat transfer based on kA and modification factor	kA_char1, kA_char2	kA_char_func

Table of characteristic lines and maps

Parameter	Description	Method
kA_char1	hot side kA modification lookup table for offdesign	None
kA_char2	cold side kA modification lookup table for offdesign	None

Condenser

Class documentation and example: Condenser

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix
energy_balance_constraints	hot side to cold side heat transfer equation	energy_balance_func

Table of parameters

Parameter	Description	Quantity	Method
Q	heat transfer from hot side	heat	energy_balance_hot_func
kA	heat transfer coefficient considering terminal temperature differences	heat_transfer_coefficient	kA_func
td_log	logarithmic temperature difference	temperature_difference	None
ttd_u	terminal temperature difference at hot side inlet to cold side outlet	temperature_difference	ttd_u_func
ttd_l	terminal temperature difference at hot side outlet to cold side inlet	temperature_difference	ttd_l_func
ttd_min	minimum terminal temperature difference	temperature_difference	ttd_min_func
pr1	hot side outlet to inlet pressure ratio	ratio	pr_structure_matrix
pr2	cold side outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp1	hot side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
dp2	cold side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta1	hot side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
zeta2	cold side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
eff_cold	heat exchanger effectiveness for cold side	efficiency	eff_cold_func
eff_hot	heat exchanger effectiveness for hot side	efficiency	eff_hot_func
eff_max	maximum heat exchanger effectiveness	efficiency	eff_max_func
subcooling	allow subcooling in the condenser	None	subcooling_func

Table of parameter groups

Parameter	Description	Required parameters	Method
kA_char	equation for heat transfer based on kA and modification factor	kA_char1, kA_char2	kA_char_func

Table of characteristic lines and maps

Parameter	Description	Method
kA_char1	hot side kA modification lookup table for offdesign	None
kA_char2	cold side kA modification lookup table for offdesign	None

Desuperheater

Class documentation and example: Desuperheater

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix
energy_balance_constraints	hot side to cold side heat transfer equation	energy_balance_func
saturated_gas_constraints	equation for saturated gas at hot side outlet	saturated_gas_func

Table of parameters

Parameter	Description	Quantity	Method
Q	heat transfer from hot side	heat	energy_balance_hot_func
kA	heat transfer coefficient considering terminal temperature differences	heat_transfer_coefficient	kA_func
td_log	logarithmic temperature difference	temperature_difference	None
ttd_u	terminal temperature difference at hot side inlet to cold side outlet	temperature_difference	ttd_u_func
ttd_l	terminal temperature difference at hot side outlet to cold side inlet	temperature_difference	ttd_l_func
ttd_min	minimum terminal temperature difference	temperature_difference	ttd_min_func
pr1	hot side outlet to inlet pressure ratio	ratio	pr_structure_matrix
pr2	cold side outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp1	hot side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
dp2	cold side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta1	hot side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
zeta2	cold side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
eff_cold	heat exchanger effectiveness for cold side	efficiency	eff_cold_func
eff_hot	heat exchanger effectiveness for hot side	efficiency	eff_hot_func
eff_max	maximum heat exchanger effectiveness	efficiency	eff_max_func

Table of parameter groups

Parameter	Description	Required parameters	Method
kA_char	equation for heat transfer based on kA and modification factor	kA_char1, kA_char2	kA_char_func

Table of characteristic lines and maps

Parameter	Description	Method
kA_char1	hot side kA modification lookup table for offdesign	None
kA_char2	cold side kA modification lookup table for offdesign	None

SectionedHeatExchanger

Class documentation and example: SectionedHeatExchanger

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix
energy_balance_constraints	hot side to cold side heat transfer equation	energy_balance_func

Table of parameters

Parameter	Description	Quantity	Method
Q	heat transfer from hot side	heat	energy_balance_hot_func
kA	heat transfer coefficient considering terminal temperature differences	heat_transfer_coefficient	kA_func
td_log	logarithmic temperature difference	temperature_difference	None
ttd_u	terminal temperature difference at hot side inlet to cold side outlet	temperature_difference	ttd_u_func
ttd_l	terminal temperature difference at hot side outlet to cold side inlet	temperature_difference	ttd_l_func
ttd_min	minimum terminal temperature difference	temperature_difference	ttd_min_func
pr1	hot side outlet to inlet pressure ratio	ratio	pr_structure_matrix
pr2	cold side outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp1	hot side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
dp2	cold side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta1	hot side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
zeta2	cold side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
eff_cold	heat exchanger effectiveness for cold side	efficiency	eff_cold_func
eff_hot	heat exchanger effectiveness for hot side	efficiency	eff_hot_func
eff_max	maximum heat exchanger effectiveness	efficiency	eff_max_func
num_sections	number of sections of the heat exchanger	None	None
UA	sum of UA values of all sections of heat exchanger	heat_transfer_coefficient	UA_func
refrigerant_index	side on which the refrigerant is flowing (0: hot, 1:cold)	None	None
re_exp_r	Reynolds exponent for UA modification based on refrigerant side mass flow	None	None
re_exp_sf	Reynolds exponent for UA modification based on secondary fluid side mass flow	None	None
alpha_ratio	secondary to refrigerant side convective heat transfer coefficient ratio	ratio	None
area_ratio	secondary to refrigerant side heat transfer area ratio	ratio	None
td_pinch	equation for minimum pinch	temperature_difference	td_pinch_func

Table of parameter groups

Parameter	Description	Required parameters	Method
kA_char	equation for heat transfer based on kA and modification factor	kA_char1, kA_char2	kA_char_func
UA_cecchinato	equation for UA modification in offdesign	re_exp_r, re_exp_sf, alpha_ratio, area_ratio	UA_cecchinato_func

Table of characteristic lines and maps

Parameter	Description	Method
kA_char1	hot side kA modification lookup table for offdesign	None
kA_char2	cold side kA modification lookup table for offdesign	None

MovingBoundaryHeatExchanger

Class documentation and example: MovingBoundaryHeatExchanger

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix
energy_balance_constraints	hot side to cold side heat transfer equation	energy_balance_func

Table of parameters

Parameter	Description	Quantity	Method
Q	heat transfer from hot side	heat	energy_balance_hot_func
kA	heat transfer coefficient considering terminal temperature differences	heat_transfer_coefficient	kA_func
td_log	logarithmic temperature difference	temperature_difference	None
ttd_u	terminal temperature difference at hot side inlet to cold side outlet	temperature_difference	ttd_u_func
ttd_l	terminal temperature difference at hot side outlet to cold side inlet	temperature_difference	ttd_l_func
ttd_min	minimum terminal temperature difference	temperature_difference	ttd_min_func
pr1	hot side outlet to inlet pressure ratio	ratio	pr_structure_matrix
pr2	cold side outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp1	hot side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
dp2	cold side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta1	hot side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
zeta2	cold side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
eff_cold	heat exchanger effectiveness for cold side	efficiency	eff_cold_func
eff_hot	heat exchanger effectiveness for hot side	efficiency	eff_hot_func
eff_max	maximum heat exchanger effectiveness	efficiency	eff_max_func
UA	sum of UA values of all sections of heat exchanger	heat_transfer_coefficient	UA_func
refrigerant_index	side on which the refrigerant is flowing (0: hot, 1:cold)	None	None
re_exp_r	Reynolds exponent for UA modification based on refrigerant side mass flow	None	None
re_exp_sf	Reynolds exponent for UA modification based on secondary fluid side mass flow	None	None
alpha_ratio	secondary to refrigerant side convective heat transfer coefficient ratio	ratio	None
area_ratio	secondary to refrigerant side heat transfer area ratio	ratio	None
td_pinch	equation for minimum pinch	temperature_difference	td_pinch_func

Table of parameter groups

Parameter	Description	Required parameters	Method
kA_char	equation for heat transfer based on kA and modification factor	kA_char1, kA_char2	kA_char_func
UA_cecchinato	equation for UA modification in offdesign	re_exp_r, re_exp_sf, alpha_ratio, area_ratio	UA_cecchinato_func

Table of characteristic lines and maps

Parameter	Description	Method
kA_char1	hot side kA modification lookup table for offdesign	None
kA_char2	cold side kA modification lookup table for offdesign	None

SimpleHeatExchanger

Class documentation and example: SimpleHeatExchanger

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
power_connector_location	None	None	None
Q	heat transfer	heat	energy_balance_func
pr	outlet ot inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta	non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
D [1]	diameter of channel	length	None
L [1]	length of channel	length	None
ks [1]	roughness of wall material	length	None
ks_HW [1]	Hazen-Williams roughness	None	None
kA [1]	heat transfer coefficient considering ambient temperature	heat_transfer_coefficient	None
Tamb	ambient temperature	temperature	None
dissipative	None	None	None

Table of parameter groups

Parameter	Description	Required parameters	Method
darcy_group	Darcy-Weißbach equation for pressure loss	L, ks, D	darcy_func
hw_group	Hazen-Williams equation for pressure loss	L, ks_HW, D	hazen_williams_func
kA_group	equation for heat transfer based on ambient temperature and heat transfer coefficient	kA, Tamb	kA_group_func
kA_char_group	heat transfer from design heat transfer coefficient, modifier lookup table and ambient temperature	kA_char, Tamb	kA_char_group_func

Table of characteristic lines and maps

Parameter	Description	Method
kA_char	heat transfer coefficient lookup table for offdesign	None

ParabolicTrough

Class documentation and example: ParabolicTrough

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
power_connector_location	None	None	None
Q	heat transfer	heat	energy_balance_func
pr	outlet ot inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta	non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
D [1]	diameter of channel	length	None
L [1]	length of channel	length	None
ks [1]	roughness of wall material	length	None
ks_HW [1]	Hazen-Williams roughness	None	None
Tamb	ambient temperature	temperature	None
dissipative	None	None	None
E [1]	solar irradiation to the parabolic trough	heat	None
A [1]	area of the parabolic trough	area	None
eta_opt	optical efficiency	efficiency	None
c_1	thermal loss coefficient 1	None	None
c_2	thermal loss coefficient 2	None	None
iam_1	incidence angle modifier 1	None	None
iam_2	incidence angle modifier 2	None	None
aoi	angle of incidence	angle	None
doc	degree of cleanliness	ratio	None
Q_loss	heat dissipation	heat	None

Table of parameter groups

Parameter	Description	Required parameters	Method
darcy_group	Darcy-Weißbach equation for pressure loss	L, ks, D	darcy_func
hw_group	Hazen-Williams equation for pressure loss	L, ks_HW, D	hazen_williams_func
energy_group	energy balance equation of the parabolic trough	E, eta_opt, aoi, doc, c_1, c_2, iam_1, iam_2, A, Tamb	energy_group_func

ParallelFlowHeatExchanger

Class documentation and example: ParallelFlowHeatExchanger

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix
energy_balance_constraints	hot side to cold side heat transfer equation	energy_balance_func

Table of parameters

Parameter	Description	Quantity	Method
Q	heat transfer from hot side	heat	energy_balance_hot_func
kA	heat transfer coefficient considering terminal temperature differences	heat_transfer_coefficient	kA_func
td_log	logarithmic temperature difference	temperature_difference	None
ttd_u	terminal temperature difference at hot side inlet to cold side outlet	temperature_difference	ttd_u_func
ttd_l	terminal temperature difference at hot side outlet to cold side inlet	temperature_difference	ttd_l_func
pr1	hot side outlet to inlet pressure ratio	ratio	pr_structure_matrix
pr2	cold side outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp1	hot side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
dp2	cold side inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta1	hot side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
zeta2	cold side non-dimensional friction coefficient for pressure loss calculation	None	zeta_func

Table of parameter groups

Parameter	Description	Required parameters	Method
kA_char	equation for heat transfer based on kA and modification factor	kA_char1, kA_char2	kA_char_func

Table of characteristic lines and maps

Parameter	Description	Method
kA_char1	hot side kA modification lookup table for offdesign	None
kA_char2	cold side kA modification lookup table for offdesign	None

SolarCollector

Class documentation and example: SolarCollector

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
power_connector_location	None	None	None
Q	heat transfer	heat	energy_balance_func
pr	outlet ot inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta	non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
D [1]	diameter of channel	length	None
L [1]	length of channel	length	None
ks [1]	roughness of wall material	length	None
ks_HW [1]	Hazen-Williams roughness	None	None
Tamb	ambient air temperature	temperature	None
dissipative	None	None	None
E [1]	solar irradiation to the solar collector	heat	None
A [1]	area of the solar collector	area	None
eta_opt	optical efficiency	efficiency	None
lkf_lin	linear heat loss factor	None	None
lkf_quad	quadratic heat loss factor	None	None
Q_loss	heat dissipation	heat	None

Table of parameter groups

Parameter	Description	Required parameters	Method
darcy_group	Darcy-Weißbach equation for pressure loss	L, ks, D	darcy_func
hw_group	Hazen-Williams equation for pressure loss	L, ks_HW, D	hazen_williams_func
energy_group	energy balance equation of the solar collector	E, eta_opt, lkf_lin, lkf_quad, A, Tamb	energy_group_func

nodes

NodeBase

Class documentation and example: NodeBase

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

DropletSeparator

Class documentation and example: DropletSeparator

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass balance constraint	mass_flow_func
energy_balance_constraints	energy balance constraint	energy_balance_func
pressure_constraints	pressure equality constraints	pressure_structure_matrix
outlet_constraint_liquid	outlet 0 is saturated liquid constraint	saturated_outlet_func
outlet_constraint_gas	outlet 1 is saturated liquid constraint	saturated_outlet_func
fluid_constraints	fluid equality constraints	fluid_structure_matrix

Drum

Class documentation and example: Drum

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass balance constraint	mass_flow_func
energy_balance_constraints	energy balance constraint	energy_balance_func
pressure_constraints	pressure equality constraints	pressure_structure_matrix
outlet_constraint_liquid	outlet 0 is saturated liquid constraint	saturated_outlet_func
outlet_constraint_gas	outlet 1 is saturated liquid constraint	saturated_outlet_func
fluid_constraints	fluid equality constraints	fluid_structure_matrix

Merge

Class documentation and example: Merge

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass balance constraint	mass_flow_func
fluid_constraints	fluid mass fraction balance constraints	fluid_func
energy_balance_constraints	energy balance constraint	energy_balance_func
pressure_constraints	pressure equality constraints	pressure_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
num_in	number of inlets	None	None

Splitter

Class documentation and example: Splitter

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass balance constraint	mass_flow_func
energy_balance_constraints	equal enthalpy at all outlets constraint	enthalpy_structure_matrix
pressure_constraints	pressure equality constraints	pressure_structure_matrix
fluid_constraints	fluid equality constraints	fluid_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
num_out	number of outlets	None	None

Node

Class documentation and example: Node

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass balance constraint	mass_flow_func
pressure_constraints	pressure equality constraints	pressure_structure_matrix
outlet_enthalpy_constraints	equal enthalpy at all outlets constraint(s)	enthalpy_structure_matrix
outlet_fluid_constraints	equal fluid at all outlets constraint(s)	fluid_structure_matrix
fluid_constraints	fluid mass fraction constraints	fluid_func
energy_balance_constraints	energy balance constraint	energy_balance_func

Table of parameters

Parameter	Description	Quantity	Method
num_out	number of outlets	None	None
num_in	number of inlets	None	None

Separator

Class documentation and example: Separator

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass balance constraint	mass_flow_func
fluid_constraints	fluid mass fraction balance constraints	fluid_func
energy_balance_constraints	equal temperature at all outlets constraints	energy_balance_func
pressure_constraints	pressure equality constraints	pressure_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
num_out	number of outlets	None	None

piping

Pipe

Class documentation and example: Pipe

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
power_connector_location	None	None	None
Q	heat transfer	heat	energy_balance_func
pr	outlet ot inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta	non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
D [1]	diameter of channel	length	None
L [1]	length of channel	length	None
ks [1]	roughness of wall material	length	None
ks_HW [1]	Hazen-Williams roughness	None	None
kA [1]	heat transfer coefficient considering ambient temperature	heat_transfer_coefficient	None
Tamb	ambient temperature	temperature	None
dissipative	None	None	None
insulation_thickness	thickness of pipe insulation	length	None
insulation_tc	thermal conductivity of insulation	thermal_conductivity	None
material	None	None	None
pipe_thickness	wall thickness of pipe	length	None
environment_media	None	None	None
wind_velocity	velocity of wind at insulation surface	speed	None
pipe_depth	depth of buried pipe	length	None

Table of parameter groups

Parameter	Description	Required parameters	Method
darcy_group	Darcy-Weißbach equation for pressure loss	L, ks, D	darcy_func
hw_group	Hazen-Williams equation for pressure loss	L, ks_HW, D	hazen_williams_func
kA_group	equation for heat transfer based on ambient temperature and heat transfer coefficient	kA, Tamb	kA_group_func
kA_char_group	heat transfer from design heat transfer coefficient, modifier lookup table and ambient temperature	kA_char, Tamb	kA_char_group_func
Q_ohc_group_surface	equation for heat loss of surface pipes	insulation_thickness, insulation_tc, Tamb, material, pipe_thickness, environment_media, wind_velocity	ohc_surface_group_func
Q_ohc_group_subsurface	equation for heat loss of buried pipes	insulation_thickness, insulation_tc, Tamb, material, pipe_thickness, environment_media, pipe_depth	ohc_subsurface_group_func

Table of characteristic lines and maps

Parameter	Description	Method
kA_char	heat transfer coefficient lookup table for offdesign	None

Valve

Class documentation and example: Valve

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix
enthalpy_constraints	equation for enthalpy equality	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
pr	None	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta	None	None	zeta_func

Table of characteristic lines and maps

Parameter	Description	Method
dp_char	inlet to outlet absolute pressure change as function of mass flow lookup table	dp_char_func

power

PowerBus

Class documentation and example: PowerBus

Table of constraints

Parameter	Description	Method
energy_balance_constraint	energy balance over all inflows and outflows	energy_balance_func

Table of parameters

Parameter	Description	Quantity	Method
num_in	number of inlets	None	None
num_out	number of outlets	None	None

Generator

Class documentation and example: Generator

Table of parameters

Parameter	Description	Quantity	Method
eta	efficiency	efficiency	eta_func
delta_power	inlet to outlet power difference	power	delta_power_func

Table of characteristic lines and maps

Parameter	Description	Method
eta_char	efficiency lookup table for offdesign	eta_char_func

Motor

Class documentation and example: Motor

Table of parameters

Parameter	Description	Quantity	Method
eta	efficiency	efficiency	eta_func
delta_power	inlet to outlet power difference	power	delta_power_func

Table of characteristic lines and maps

Parameter	Description	Method
eta_char	efficiency lookup table for offdesign	eta_char_func

PowerSink

Class documentation and example: PowerSink

PowerSource

Class documentation and example: PowerSource

reactors

FuelCell

Class documentation and example: FuelCell

Table of constraints

Parameter	Description	Method
mass_flow_constraints	equations for oxygen and hydrogen mass flow relation	reactor_mass_flow_func
cooling_mass_flow_constraints	cooling fluid mass flow equality equation	cooling_mass_flow_structure_matrix
cooling_fluid_constraints	cooling fluid composition equality equation	cooling_fluid_structure_matrix
energy_balance_constraints	energy balance equation of the reactor	energy_balance_func
reactor_pressure_constraints	reactor pressure equality equations	reactor_pressure_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
P [1]	power output of the fuel cell	power	None
Q	heat output of the cooling port	heat	heat_func
pr	cooling port outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	cooling inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta	cooling port non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
eta	efficiency of the fuel cell	efficiency	eta_func
e [1]	equation for specified specific energy consumption of the fuel cell	specific_energy	specific_energy_func

WaterElectrolyzer

Class documentation and example: WaterElectrolyzer

Table of constraints

Parameter	Description	Method
mass_flow_constraints	equations for oxygen and hydrogen mass flow relation	reactor_mass_flow_func
cooling_mass_flow_constraints	cooling fluid mass flow equality equation	cooling_mass_flow_structure_matrix
cooling_fluid_constraints	cooling fluid composition equality equation	cooling_fluid_structure_matrix
energy_balance_constraints	energy balance equation of the reactor	energy_balance_func
reactor_pressure_constraints	reactor pressure equality equations	reactor_pressure_structure_matrix
gas_temperature_constraints	equation for same temperature of product gases	gas_temperature_func

Table of parameters

Parameter	Description	Quantity	Method
P [1]	power consumption of the electrolyzer	power	None
Q	heat output of the cooling port	heat	heat_func
pr	cooling port outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	cooling inlet to outlet absolute pressure change	pressure	dp_structure_matrix
zeta	cooling port non-dimensional friction coefficient for pressure loss calculation	None	zeta_func
eta	efficiency of the fuel cell	efficiency	eta_func
e [1]	equation for specified specific energy consumption of the electrolyzer	specific_energy	specific_energy_func

Table of characteristic lines and maps

Parameter	Description	Method
eta_char	efficiency lookup table for offdesign	eta_char_func

turbomachinery

Turbomachine

Class documentation and example: Turbomachine

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
P	power input/output of the component	power	energy_balance_func
pr	outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix

Compressor

Class documentation and example: Compressor

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
P	power input/output of the component	power	energy_balance_func
pr	outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
eta_s	isentropic efficiency	efficiency	eta_s_func
igva [1]	inlet guide vane angle	angle	None

Table of parameter groups

Parameter	Description	Required parameters	Method
char_map_eta_s_group	map for isentropic efficiency over speedlines and non-dimensional mass flow	char_map_eta_s, igva	char_map_eta_s_func
char_map_pr_group	map for pressure ratio over speedlines and non-dimensional mass flow	char_map_pr, igva	char_map_pr_func

Table of characteristic lines and maps

Parameter	Description	Method
eta_s_char	isentropic efficiency lookup table for offdesign	eta_s_char_func
char_map_eta_s	2D lookup table for efficiency over non-dimensional mass flow and speed line	None
char_map_pr	2D lookup table for pressure ratio over non-dimensional mass flow and speed line	None

Pump

Class documentation and example: Pump

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
P	power input/output of the component	power	energy_balance_func
pr	outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
eta_s	isentropic efficiency	efficiency	eta_s_func

Table of characteristic lines and maps

Parameter	Description	Method
eta_s_char	isentropic efficiency lookup table for offdesign	eta_s_char_func
flow_char	pressure rise over volumetric flow lookup table	flow_char_func

Turbine

Class documentation and example: Turbine

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
P	power input/output of the component	power	energy_balance_func
pr	outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
eta_s	isentropic efficiency	efficiency	eta_s_func
cone	cone law equation for offdesign	None	cone_func

Table of characteristic lines and maps

Parameter	Description	Method
eta_s_char	isentropic efficiency lookup table for offdesign	eta_s_char_func

SteamTurbine

Class documentation and example: SteamTurbine

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
P	power input/output of the component	power	energy_balance_func
pr	outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
eta_s	isentropic efficiency	efficiency	eta_s_func
cone	cone law equation for offdesign	None	cone_func
alpha	influence factor for wetness efficiency modifier	ratio	None
eta_s_dry	isentropic efficiency of dry expansion	efficiency	None

Table of parameter groups

Parameter	Description	Required parameters	Method
eta_s_dry_group	method to apply Baumann rule	alpha, eta_s_dry	eta_s_wet_func

Table of characteristic lines and maps

Parameter	Description	Method
eta_s_char	isentropic efficiency lookup table for offdesign	eta_s_char_func

TurboCompressor

Class documentation and example: TurboCompressor

Table of constraints

Parameter	Description	Method
mass_flow_constraints	mass flow equality constraint(s)	variable_equality_structure_matrix
fluid_constraints	fluid composition equality constraint(s)	variable_equality_structure_matrix

Table of parameters

Parameter	Description	Quantity	Method
P	power input/output of the component	power	energy_balance_func
pr	outlet to inlet pressure ratio	ratio	pr_structure_matrix
dp	inlet to outlet absolute pressure change	pressure	dp_structure_matrix
eta_s	isentropic efficiency	efficiency	eta_s_func
igva [1]	inlet guide vane angle	angle	None

Table of parameter groups

Parameter	Description	Required parameters	Method
char_map_eta_s_group	map for isentropic efficiency over speedlines and non-dimensional mass flow	char_map_eta_s, igva	char_map_eta_s_func
char_map_pr_group	map for pressure ratio over speedlines and non-dimensional mass flow	char_map_pr, igva	char_map_pr_func

Table of characteristic lines and maps

Parameter	Description	Method
char_map_eta_s	2D lookup table for efficiency over non-dimensional mass flow and speed line	None
char_map_pr	2D lookup table for pressure ratio over non-dimensional mass flow and speed line	None

[1] (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32)

This parameter can be made a variable, get more info here.

Component parametrisation

All parameters of components can be set and unset through the set_attr method. As seen in the tables above, there are different types of parameters:

• Simple component parameters: If an equation/method is associated with the parameter, setting a value for the parameter will activate that equation.

• Grouped component parameters: Multiple simple parameters can be part of a parameter group. To activate the equation associated with the parameter group, values for all elements of the group have to be set by the user.

• Component parameters that serve as variable in the model: Specifically in the context of grouped parameters it is possible to set one of the parameters as a variable. If values for all other parameters of the group are specified as well, then the group equation is activated and the solver will include the one parameter marked as variable in the variables.

• Component characteristics and characteristic groups: Lookup-tables are implemented here to interpolate over a variable or an expression and modify the outcome of an equation.

Component parameters

The example shows how to specify a component parameter and how to unset again at the example of the heat transfer coefficient of an evaporator.

>>> from tespy.components import HeatExchanger
>>> from tespy.tools import ComponentProperties as dc_cp
>>> import numpy as np

>>> he = HeatExchanger('evaporator')

>>> # specify the value
>>> he.set_attr(kA=1e5)
>>> he.kA.val
100000.0
>>> he.kA.is_set
True

>>> # possibilities to unset a value
>>> he.set_attr(kA=None)
>>> he.kA.is_set
False

Grouped parameters

Grouped parameters are used whenever a component property depends on multiple parameters. For instance, the pressure loss calculation via Darcy-Weissbach requires information about the length, diameter and roughness of the pipe. The solver will prompt a warning, if you do not specify all parameters required by a parameter group. If parameters of the group are missing, the equation will not be implemented by the solver.

>>> from tespy.components import Pipe, Source, Sink
>>> from tespy.networks import Network
>>> from tespy.connections import Connection

>>> nw = Network()
>>> nw.units.set_defaults(temperature="degC", pressure="bar")

>>> so = Source('source')
>>> si = Sink('sink')
>>> my_pipe = Pipe('pipe')

>>> c1 = Connection(so, 'out1', my_pipe, 'in1')
>>> c2 = Connection(my_pipe, 'out1', si, 'in1')
>>> nw.add_conns(c1, c2)
>>> c1.set_attr(fluid={"CH4": 1}, m=1, p=10, T=25)
>>> c2.set_attr(p0=10, T=25)

>>> # specify grouped parameters
>>> my_pipe.set_attr(D=0.1, L=20, ks=0.00005)
>>> nw.solve('design', init_only=True)
>>> my_pipe.darcy_group.is_set
True

>>> # the solver will not apply an equation, since the information of the
>>> # pipe's length is now missing (by removing it as follows).
>>> c2.set_attr(p=10)
>>> my_pipe.set_attr(L=None)
>>> nw.solve('design', init_only=True)
>>> my_pipe.darcy_group.is_set
False

Component variables

It is possible to use component parameters as variables of your system of equations. In the component parameter list, if a parameter can be a string, it is possible to specify this parameter as custom variable. For example, given the pressure ratio pr, length L and roughness ks of a pipe you may want to calculate the pipe’s diameter D required to achieve the specified pressure ratio. In this case you need to specify the diameter the following way.

>>> # make diameter variable of system
>>> my_pipe.set_attr(pr=0.98, L=100, ks=0.00002, D='var')
>>> c2.set_attr(p=None)
>>> nw.solve("design", init_only=True)
>>> my_pipe.darcy_group.is_set
True

It is also possible to set value boundaries for you custom variable. You can do this, if you expect the result to be within a specific range. But beware: This might result in a non converging simulation, if the actual value is out of your specified range.

>>> my_pipe.D.max_val = 0.3
>>> round(my_pipe.D.max_val, 1)
0.3

Component characteristics

Several components integrate parameters using a characteristic function. These parameters come with default characteristics. The default characteristics available can be found in the this section. Of course, it is possible to specify your own data for these characteristic functions.

Note

There are two different characteristics specifications

The characteristic function can be an auxiliary parameter of a different component property. This is the case for kA_char1 and kA_char2 of heat exchangers as well as the characteristics of a combustion engine: tiP_char, Q1_char, Q2_char and Qloss_char.

For all other components, the characteristic function is an individual parameter of the component.

What does this mean?

For the auxiliary functionality the main parameter, e.g. kA_char of a heat exchanger must be set .kA_char.is_set=True.

For the other functionality the characteristics parameter must be set e.g. .eta_s_char.is_set=True.

For example, kA_char specification for heat exchangers:

>>> from tespy.components import HeatExchanger
>>> from tespy.tools.characteristics import load_default_char as ldc
>>> from tespy.tools.characteristics import CharLine

>>> nw = Network(iterinfo=False)
>>> nw.units.set_defaults(temperature="degC", pressure="bar")

>>> he = HeatExchanger('evaporator')
>>> cond = Source('condensate')
>>> steam = Sink('steam')
>>> gas_hot = Source('air inlet')
>>> gas_cold = Sink('air outlet')

>>> c1 = Connection(cond, "out1", he, "in2")
>>> c2 = Connection(he, "out2", steam, "in1")
>>> c3 = Connection(gas_hot, "out1", he, "in1")
>>> c4 = Connection(he, "out1", gas_cold, "in1")

>>> nw.add_conns(c1, c2, c3, c4)

>>> c1.set_attr(fluid={'water': 1}, m=10, p=10, x=0)
>>> c2.set_attr(p=10, x=1)
>>> c3.set_attr(fluid={'air': 1}, T=250, p=1)
>>> c4.set_attr(T=200, p=1)

>>> nw.solve("design")
>>> nw.save("design_case.json")
>>> round(he.kA.val)
503013

>>> # the characteristic function is made for offdesign calculation.
>>> he.set_attr(offdesign=["kA_char"])
>>> c4.set_attr(design=["T"])
>>> nw.solve("offdesign", design_path="design_case.json")
>>> # since we did not change any property, the offdesign case yields the
>>> # same value as the design kA value
>>> round(he.kA.val)
503013

>>> c1.set_attr(m=9)
>>> # use a characteristic line from the defaults: specify the component, the
>>> # parameter and the name of the characteristic function. Also, specify,
>>> # what type of characteristic function you want to use.
>>> kA_char1 = ldc('HeatExchanger', 'kA_char1', 'DEFAULT', CharLine)
>>> kA_char2 = ldc('HeatExchanger', 'kA_char2', 'EVAPORATING FLUID', CharLine)
>>> he.set_attr(kA_char2=kA_char2)
>>> nw.solve("offdesign", design_path="design_case.json")
>>> round(he.kA.val)
481745

>>> # specification of a data container yields the same result. It is
>>> # additionally possible to specify the characteristics parameter, e.g.
>>> # mass flow for kA_char1 (identical to default case) and volumetric
>>> # flow for kA_char2
>>> he.set_attr(
...     kA_char1={'char_func': kA_char1, 'param': 'm'},
...     kA_char2={'char_func': kA_char2, 'param': 'v'}
... )
>>> nw.solve("offdesign", design_path="design_case.json")
>>> round(he.kA.val)
481745

>>> # or use custom values for the characteristic line e.g. kA vs volumetric
>>> # flow
>>> x = np.array([0, 0.5, 1, 2])
>>> y = np.array([0, 0.8, 1, 1.2])
>>> kA_char2 = CharLine(x, y)
>>> he.set_attr(kA_char2={'char_func': kA_char2, 'param': 'v'})
>>> nw.solve("offdesign", design_path="design_case.json")
>>> round(he.kA.val)
475107

Full working example for eta_s_char specification of a turbine.

>>> from tespy.components import Sink, Source, Turbine
>>> from tespy.connections import Connection
>>> from tespy.networks import Network
>>> from tespy.tools.characteristics import CharLine
>>> import numpy as np

>>> nw = Network(iterinfo=False)
>>> nw.units.set_defaults(
...     temperature="degC", pressure="bar", enthalpy="kJ/kg"
... )
>>> si = Sink('sink')
>>> so = Source('source')
>>> t = Turbine('turbine')
>>> inc = Connection(so, 'out1', t, 'in1')
>>> outg = Connection(t, 'out1', si, 'in1')
>>> nw.add_conns(inc, outg)

>>> # design value specification, cone law and eta_s characteristic as
>>> # offdesign parameters
>>> eta_s_design = 0.855
>>> t.set_attr(
...     eta_s=eta_s_design,
...     design=['eta_s'], offdesign=['eta_s_char','cone']
... )

>>> # Characteristics x as m/m_design and y as eta_s(m)/eta_s_design
>>> # make sure to cross the 1/1 point (design point) to yield the same
>>> # output in the design state of the system
>>> line = CharLine(
...     x=[0.1, 0.3, 0.5, 0.7, 0.9, 1, 1.1],
...     y=np.array([0.6, 0.65, 0.75, 0.82, 0.85, 0.855, 0.79]) / eta_s_design
... )

>>> # default parameter for x is m / m_design
>>> t.set_attr(eta_s_char={'char_func': line})
>>> inc.set_attr(fluid={'water': 1}, m=10, T=550, p=110, design=['p'])
>>> outg.set_attr(p=0.5)
>>> nw.solve('design')
>>> nw.save('tmp.json')
>>> # change mass flow value, e.g. 3 kg/s and run offdesign calculation
>>> inc.set_attr(m=3)
>>> nw.solve('offdesign', design_path='tmp.json')
>>> # isentropic efficiency should be at 0.65
>>> round(t.eta_s.val, 2)
0.65

>>> # alternatively, we can specify the volumetric flow v / v_design for
>>> # the x lookup
>>> t.set_attr(eta_s_char={'param': 'v'})
>>> nw.solve('offdesign', design_path='tmp.json')
>>> round(t.eta_s.val, 2)
0.84

Finally, it is possible to allow value extrapolation at the lower and upper limit of the value range at the creation of characteristic lines. Set the extrapolation parameter to True.

# use custom specification parameters
>>> x = np.array([0, 0.5, 1, 2])
>>> y = np.array([0, 0.8, 1, 1.2])
>>> kA_char1 = CharLine(x, y, extrapolate=True)
>>> kA_char1.extrapolate
True

>>> # set extrapolation to True for existing lines, e.g.
>>> he.kA_char1.char_func.extrapolate = True
>>> he.kA_char1.char_func.extrapolate
True

For more information on how the characteristic functions work click here.

Component customization

Please check the advanced features on how to

• extend existing components with additional parameters and equations or

• create your own components from scratch