v0.4¶

Changelog of the v0.4 release series.

v0.4.4 - Reynolds’ Reminiscence (July, 14, 2021)¶

Documentation¶

Fix some typos here and there.

Bug Fixes¶

Fix pandas version 1.3.0 dependencies (PR #277).
Add missing results for some components in the results DataFrame of the network (PR #277).
Fix exergy balance equation of class merge tespy.components.nodes.merge.Merge.exergy_balance (PR #280).
Fix a lot of DeprecationWarnings in pandas (PR #280).

Other Changes¶

Add warning logs for missing fluid composition data in the initialisation process of the network (PR #278).
Add Dodecane to the available fuels for combustion (PR #273).
Add tests for the solar energy generating system (PR #280).

Contributors¶

Francesco Witte (@fwitte)

v0.4.3-003 - Grassmann’s Graph (May, 17, 2021)¶

Documentation¶

Fix typos in the HeatExchanger classes API docs.
Add two more examples for exergy analysis setups.

Other Changes¶

Remove Python3.6 support.
Make it possible to include results in automatic model report, for more information see the corresponding section in the documentation: TESPy Networks Postprocessing (PR #267).

Contributors¶

Francesco Witte (@fwitte)

v0.4.3-001 - Grassmann’s Graph (May, 12, 2021)¶

Documentation¶

Some minor changes in documentation.

Other Changes¶

Check for key in dictionary instead of key in dictionary.keys() in boolean operations (PR #264).
Rename GitHub branches: master to main (Issue #266).

Contributors¶

Francesco Witte (@fwitte)

v0.4.3 - Grassmann’s Graph (April, 29, 2021)¶

New Features¶

Automatic provision of input data for the sankey diagram class of the plotly library to generate exergy sankey diagrams. For example, the diagram of the solar thermal power plant presented in the thermodynamic analyses section

(PR #251).
The results of your simulation are much more easy to bulk access: The tespy.networks.network.Network class provides you with a results dictionary containing DataFrames with all data necessary. The keys of the dictionary are:
- 'Connection'
- the class names of the different components used, e.g. 'Turbine' or 'HeatExchanger'
- the labels of the busses, e.g. 'input power'
The pandas DataFrame provides you with the SI-values for components and busses as well as all fluid property data of the connections in respective specified unit. For example:
```
mynetwork.results['Connection']
mynetwork.results['Turbine']
```
(PR #255).

Documentation¶

An own chapter for the exergy analysis toolbox has been added (PR #251).
Fix some typos in the code of heat pump tutorial (PR #260).
Update component parameter data type specifications according to 0.4.x API in docs and add missing parameters in HeatExchanger classes (PR #260).
Fix broken links to characteristic map functions of class tespy.components.turbomachinery.compressor.Compressor (PR #263).

Bug Fixes¶

Add missing exergy balance method of class Drum (#1eb92e3).
Add missing specified values of temperature difference to boiling point to connection report (PR #250).
Fix Reynolds value ranges for Hanakov and Blasius equations in calculation of Darcy friction factor (#ce6bef9).

Other Changes¶

Add a timestamp for the automatic model documentation feature (PR #248).
Move from travis to GitHub actions (PR #249).
Specified Bus values are now colored in the tespy.networks.network.Network.print_results() method (PR #255).
Remove building figures for characteristics from docs generation (PR #251).

Contributors¶

v0.4.2 - Fixes for User’s Universe (February, 11, 2021)¶

API Fixes/Changes¶

Due to a bug/double structure in the network properties of a model, specification of component or connection parameters when the component or connection instance was accessed via its label within the network, the wrong copy of the instance was accessed when using PyGMO in some cases. The method off accessing components and connections via label has therefore changed in the following way.

Old method:
```
conn = mynetwork.connections['connection label']
comp = mynetwork.components['component label']
```
New method:
```
conn = mynetwork.get_conn('connection label')
comp = mynetwork.get_comp('component label')
```
To iterate through all components or connections of the network use something like:
```
for conn in mynetwork.conns['object']:
    print(conn.label)

for comp in mynetwork.comps['object']:
    print(comp.label)
```
Accessing busses remains untouched (PR #247)

Bug Fixes¶

Saving data of characteristics and reloading from the .csv file structure was broken if more than one component of the same class was part of the network (PR #246).

Contributors¶

Francesco Witte (@fwitte)

v0.4.1 - User’s Universe (February, 7, 2021)¶

New Features¶

Add functionalities for user defined equations. The user can define individual functions that can be applied on connection parameters. E.g. in order to couple mass flow values at some point of the network to temperature values at a different point. Generic equations can be applied: There are no restrictions as long as the partial derivatives are provided correctly. For extensive examples have a look at the API documentation of class tespy.tools.helpers.UserDefinedEquation or in the respective section in the online documentation (PR #245).

Documentation¶

Bug Fixes¶

Fix RuntimeError in CombustionChamberStoich class (PR #244).

Other Changes¶

Contributors¶

Francesco Witte (@fwitte)
@govind-menon110

v0.4.0 - Gibbs’ Gallery (January, 27, 2021)¶

API Changes¶

In order to stick closer to the PEP 8 style guide we changed the names of all classes in TESPy to CamelCase instead of snake_case as the latter is reserved for methods. This means, you need to change your import like in the following examples:

from tespy.components import Turbine, CombustionEngine
from tespy.components import HeatExchanger, HeatExchangerSimple
from tespy.connections import Connection
from tespy.connections import Bus
from tespy.connections import Ref
from tespy.networks import Network
from tespy.tools.characteristics import CharLine

# but keep e.g.
from tespy.networks import load_network

The examples in the online documentation and the examples repository have been adjusted accordingly (PR #237).

The definition of power and heat transfer of the components tespy.components.combustion.engine.CombustionEngine and tespy.components.customs.orc_evaporator.ORCEvaporator as well as the heat loss values of the components tespy.components.heat_exchangers.solar_collector.SolarCollector and tespy.components.heat_exchangers.parabolic_trough.ParabolicTrough have been changed to negative sign as all values are energy output streams (PR #215) and (PR #243).
Specification of characteristics has changed. Use a dictionary instead of DataContainer specification if you want to update more than just the characteristic function. E.g. if you have the measurement data for the isentropic efficiency of a turbine like below. X-data are ratio of actual mass flow to design mass flow and y values are the ratio of actual isentropic efficiency to design value of the turbine. Say, you want to specify these data as tespy.tools.characteristics.CharLine and the characteristics should be applied. In order to do that, pass a dictionary that contains the CharLine object as 'char_func' and set is_set to True:
```
from tespy.components import Turbine
from tespy.tools.characteristics import CharLine
import numpy as np

t = Turbine('myturbine')
# ... design specs
# ... design calculation
# offdesign case, use char line
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]) / 0.855)
t.set_attr(eta_s_char={'char_func': line, 'is_set': True})
```
More information on characteristics specification and a fully working example can be found in the corresponding section in the online documentation (PR #243).
Characteristic Maps behave differently: Instead of two output dimensions z1 and z2 they do now only hold one output dimension z. The calculation of z as function of x and y does not change (PR #243).
The char_map parameter of the component tespy.components.turbomachinery.compressor.Compressor has been split up into two separate parameters:
- char_map_eta_s: Map linking non-dimensional mass flow and speed line to isentropic efficiency.
- char_map_pr: Map linking non-dimensional mass flow and speed line to pressure ratio.
(PR #243).
Remove class Node (PR #243).
For reference specification, the delta parameter must be specified in the corresponding network unit, e.g. if your pressure unit is set to bar, the delta will be interpreted in bar, too (PR #243).

New Features¶

Automatic TESPy model documentation: You can generate an automatic model report in LaTeX format after a simulation. The document will contain all input parameters specified as well as all equations and characteristics applied in your previous simulation. Import and function call are implemented as follows. This feature will be under future development, driven by user requirements. If you have any feedback or suggestions or want to add new data you are very welcome to submit an issue in the GitHub repository or even open a pull request. The documentation code is located in the tespy.tools.document_models module.
```
from tespy.tools import document_model

document_model(mynetwork)
```
For further information also check the corresponding section in the online documentation (PR #243).
IF97 back end for properties of water is now supported. A fix was implemented in TESPy to solve convergence issues near saturation in region 1. You can use the back end by adding 'IF97::water' to your network’s fluid list (PR #238, also see CoolProp Issue #1918).
An automatic exergy analysis has been added. The method reliably works for temperature values that are larger than the ambient temperature. An implementation for temperature values crossing or below the ambient temperature is in the making. Also, combustion processes are not covered for now (PR #215). If you like to contribute, you are welcome to submit an issue in the GitHub repository.
Add a method get_plotting_data to each component to export the input data required by FluProDia in order to generate the data required to display state changes in the components in a fluid property diagram. Each component returns a nested dictionary containing the respective data. E.g. the return value of a valve:
```
 {1: {
     'isoline_property': 'h',
     'isoline_value': 773.8970004397456,
     'isoline_value_end': 773.8970004397456,
     'starting_point_property': 'p',
     'starting_point_value': 51.164150405253665,
     'ending_point_property': 'p',
     'ending_point_value': 6.831002318100345
}}
```
The diagrams could look like this:

Figure: logph diagram of NH3 with a simple heat pump cycle.¶

Figure: Ts diagram of NH3 with a simple heat pump cycle.¶

For more information see the respective documentation section (PR #234).
Add a flag to deactivate calculation of all component equations in every iteration. This improves stability in some cases but may reduce calculation speed (PR #226). To deactivate simply specify on calling the tespy.networks.network.Network.solve() method:
```
mynetwork.solve('design', always_all_equations=False)
```
Add a flag use cuda instead of numpy for matrix inversion. With cuda matrix inversion is outsourced to the graphics card. Using cuda additionally requires cupy installed on your machine (PR #226). To activate simply specify on calling the tespy.networks.network.Network.solve() method:
```
mynetwork.solve('design', use_cuda=True)
```
For more information on cupy visit the online documentation.

Note

In general, calculation time depends on many factors of your local machine. You should try and check, if using cuda or disabling always all equations benefits your calculation times individually.

Documentation¶

Fix several broken links and typos (PR #236).

Bug Fixes¶

Fix a bug, where checking if parameters are numeric in the set_attr() methods of classes connection, bus and component failed in case special numpy number types were passed (#daa1ecb, #b420396).

Other Changes¶

Adjust value limits for some component parameters¶
component	parameter	new value
heat_exchanger_simple	`zeta.max_val`	1e15
	`ks.max_val` (for Hazen-Williams equation)	200
valve	`zeta.max_val`	1e15

On some machines the coloring of the results printout does not work and displaces the table in an ugly way. To avoid this, the coloring is changed to optional (PR #229). Use the following line for non-colored printouts:
```
mynetwork.print_results(colored=False)
```
An error message is raised in case the user specifies a fluid vector containing fluids, that are not part of the network’s fluid list (PR #233).
An understandable error message is raised in case the user misses out on fluids required by components of class CombustionChamber or CombustionEngine (#7adff43a).
For improved convergence stability of the methods tespy.components.heat_exchangers.simple.HeatExchangerSimple.kA_group_func and tespy.components.heat_exchangers.simple.HeatExchangerSimple.kA_char_group_func, the logarithmic temperature difference is calculated based on the mean temperature difference between ambient and inlet and outlet temperature, if the terminal temperature differences do not have the same sign (PR #225).
Changes in the equation management of components for much easier maintenance and future development (PR #243).

Contributors¶

Francesco Witte (@fwitte)
@juliusmeier
@jbueck
Markus Brandt (@MarBrandt)