pytanksim.classes.simresultsclass

Contains the SimResults class.

It is used for storing and post-processing the results of dynamic simulations.

Classes

SimResults

Class for storing the results of dynamic simulations.

Module Contents

class pytanksim.classes.simresultsclass.SimResults(pressure, temperature, time, moles_adsorbed, moles_gas, moles_liquid, moles_supercritical, tank_params, sim_params, stop_reason, sim_type=None, inserted_amount=0, flow_energy_in=0, cooling_required=0, heating_required=0, cooling_additional=0, heating_additional=0, heat_leak_in=0, vented_amount=0, vented_energy=0)

Class for storing the results of dynamic simulations.

It comes with methods for exporting the results to csv, plotting the results, and for combining the results of multiple simulations.

df

A dataframe containing the results of dynamic simulations. See notes for the column names and the variables each column has.

Type:

pd.DataFrame

Notes

Below is a list of the pandas DataFrame column names and a short description of the variable stored inside each series.

  • t: time (seconds)

  • p: pressure (Pa)

  • T: temperature (K)

  • na: amount of fluid adsorbed (moles)

  • ng: amount of fluid in gaseous form (moles)

  • nl: amount of fluid in liquid form (moles)

  • ns: amount of fluid in supercritical form (moles)

  • Qcoolreq: cumulative amount of cooling required (J)

  • Qheatreq: cumulative amount of heating required (J)

  • nout: cumulative amount of fluid vented (moles)

  • Hout: cumulative amount of vented fluid enthalpy (J)

  • nin: cumulative amount of fluid inserted (moles)

  • Hin: cumulative amount of inserted fluid enthalpy (J)

  • Qcooladd: cumulative amount of user specified cooling (J)

  • Qheatadd: cumulative amount of user specified heating (J)

  • Qleak: cumulative amount of heat leakage into the tank (J)

  • ma: mass of fluid adsorbed (kg)

  • mg: mass of fluid in gaseous form (kg)

  • ml: mass of fluid in liquid form (kg)

  • ms: mass of fluid in supercritical form (kg)

  • mout: cumulative mass of fluid vented (kg)

  • min: cumulative mass of fluid inserted (kg)

  • na_dot: the amount of fluid (moles) being adsorbed per second.

  • ng_dot: the first derivative of the amount of fluid in gaseous form w.r.t. time. Its unit is mol/s.

  • nl_dot: the first derivative of the amount of fluid in liquid form w.r.t. time. Its unit is mol/s

  • ns_dot: the first derivative of the amount of fluid in supercritical form w.r.t. time. Its unit is mol/s.

  • Qcoolreq_dot: the cooling power (W) required to maintain a constant pressure during refuel.

  • Qheatreq_dot: the heating power (W) required to maintain a constant pressure during discharge.

  • nout_dot: the rate at which fluid is being vented from the tank (mol/s).

  • Hout_dot: the rate at which enthalpy is taken away by fluid leaving the tank (W).

  • nin_dot: the rate at which fluid is entering the tank (mol/s).

  • Hin_dot: the rate at which enthalpy is added by fluid fluid entering the tank (W).

  • Qcooladd_dot: the user specified cooling power (W).

  • Qheatadd_dot: the user specified heating power (W).

  • Qleak_dot: the rate of heat leakage into the tank (W).

  • ma_dot: the mass of fluid (kg) being adsorbed per second.

  • mg_dot: the first derivative of the mass of fluid in gaseous form w.r.t. time. Its unit is kg/s.

  • ml_dot: the first derivative of the mass of fluid in liquid form w.r.t. time. Its unit is kg/s.

  • ms_dot: the first derivative of the mass of fluid in supercritical form w.r.t. time. Its unit is kg/s.

  • mout_dot: the rate at which fluid is being vented from the tank (kg/s).

  • min_dot: the rate at which fluid is being inserted into the tank (kg/s).

Initialize a SimResults object.

Parameters:

  • pressure (Union[List[float], np.ndarray]) – A list or numpy array containing the pressure values inside of the tank (Pa) as it changes over time.

  • temperature (Union[List[float], np.ndarray]) – A list or numpy array containing the temperature values inside of the tank (K) as it changes over time.

  • time (Union[List[float], np.ndarray]) – A list or numpy array containing the simulation time points (s) at which results are reported.

  • moles_adsorbed (Union[List[float], np.ndarray]) – A list or numpy array containing the amount of fluid that is adsorbed (moles) at given points in time.

  • moles_gas (Union[List[float], np.ndarray]) – A list or numpy array containing the amount of fluid stored in gaseous form (moles) at given points in time.

  • moles_liquid (Union[List[float], np.ndarray]) – A list or numpy array containing the amount of fluid stored in liquid form (moles) at given points in time.

  • moles_supercritical (Union[List[float], np.ndarray]) – A list or numpy array containing the amount of supercritical fluid in the tank (moles) at given points in time.

  • tank_params (Union[StorageTank, SorbentTank]) – An object containing the parameters of the storage tank used for the dynamic simulation.

  • sim_type (str) – A string describing the type of simulation that was conducted.

  • sim_params (SimParams) – An object containing the parameters used for the simulation.

  • stop_reason (str) – A string describing why the simulation was terminated.

  • inserted_amount (Union[List[float], np.ndarray], optional) – The cumulative amount of fluid inserted into the tank (moles) throughout the dynamic simulation. The default is 0.

  • flow_energy_in (Union[List[float], np.ndarray], optional) – The cumulative amount of enthalpy brought by fluid flowing into the tank (J) throughout the dynamic simulation. The default is 0.

  • cooling_required (Union[List[float], np.ndarray], optional) – The cumulative amount of cooling required (J) to maintain a constant pressure during refueling. The default is 0.

  • heating_required (Union[List[float], np.ndarray], optional) – The cumulative amount of heating required (J) to maintain a constant pressure during discharging. The default is 0.

  • cooling_additional (Union[List[float], np.ndarray], optional) – The cumulative amount of additional cooling (J) inputted to the simulation via a user-defined function. The default is 0.

  • heating_additional (Union[List[float], np.ndarray], optional) – The cumulative amount of additional heating (J) inputted to the simulation via a user-defined function. The default is 0.

  • heat_leak_in (Union[List[float], np.ndarray], optional) – The cumulative amount of heat (J) which has leaked into the tank from the environment. The default is 0.

  • vented_amount (Union[List[float], np.ndarray], optional) – The cumulative amount of fluid vented (moles) throughout the dynamic simulation. The default is 0.

  • vented_energy (Union[List[float], np.ndarray], optional) – The cumulative amount of enthalpy taken by fluid flowing out of the tank (J) throughout the dynamic simulation. The default is 0.

Returns:

An object containing the results of a dynamic simulation run by pytanksim. It has functions for exporting and plotting.

Return type:

SimResults

get_final_conditions(idx=- 1)

Output final tank conditions at the end of the simulation.

Parameters:

idx (int, optional) – The index of the simulation results array from which the values are to be taken. The default is -1 (the last time point in the simulation).

Returns:

A dictionary containing tank conditions at’idx’.

Return type:

dict

to_csv(filename, verbose=True)

Export simulation results to a csv file.

Parameters:

  • filename (str) – The desired filepath for the csv file to be created.

  • verbose (bool, optional) – Whether or nor to report the completion of the export. The default value is True.

classmethod from_csv(filename, import_components=False)

Import simulation results from a csv file.

Parameters:

  • filename (str) – Path to a csv file which was exported by pytanksim.

  • import_components (bool) – If True, this function will return a tuple with contents as follows: SimResults, StorageTank, SimParams. If False, this function will only return the SimResults object. The default option is False.

Returns:

A single object containing the simulation results, or a tuple with SimResults, StorageTank, and SimParams objects.

Return type:

SimResults|Tuple

interpolate(x_var='t')

Interpolate simulation results between points.

Parameters:

x_var (str, optional) – Variable to be used as a basis/input for interpolation.The default is “t”.

Returns:

A dictionary containing functions which interpolate each variable in the SimResults object w.r.t. the variable chosen in x_var.

Return type:

“dict[Callable[[float], float]]”

plot(x_axis, y_axes, colors=['r', 'b', 'g'])

Plot the results of the simulation.

Parameters:

  • x_axis (str) – A string specifying what variable should be on the x-axis. See notes for valid inputs.

  • y_axes (Union[str, List[str]]) – A string or a list of strings specifying what is to be plotted on the y-axis. See notes for valid inputs

  • colors (Union[str, List[str]], optional) – A string or a list of strings specifying colors for the lines in the plot. The default is [“r”, “b”, “g”].

Raises:

ValueError – If more than 3 y-variables are specified to be plotted.

Returns:

A matplolib axis or a numpy array of several axes.

Return type:

Union[np.ndarray, plt.Axes]

Notes

Below is a list of valid string inputs for x_axis and y_axes along with the variables they represent.

  • t: time (seconds)

  • p: pressure (Pa)

  • T: temperature (K)

  • na: amount of fluid adsorbed (moles)

  • ng: amount of fluid in gaseous form (moles)

  • nl: amount of fluid in liquid form (moles)

  • ns: amount of fluid in supercritical form (moles)

  • Qcoolreq: cumulative amount of cooling required (J)

  • Qheatreq: cumulative amount of heating required (J)

  • nout: cumulative amount of fluid vented (moles)

  • Hout: cumulative amount of vented fluid enthalpy (J)

  • nin: cumulative amount of fluid inserted (moles)

  • Hin: cumulative amount of inserted fluid enthalpy (J)

  • Qcooladd: cumulative amount of user specified cooling (J)

  • Qheatadd: cumulative amount of user specified heating (J)

  • Qleak: cumulative amount of heat leakage into the tank (J)

  • ma: mass of fluid adsorbed (kg)

  • mg: mass of fluid in gaseous form (kg)

  • ml: mass of fluid in liquid form (kg)

  • ms: mass of fluid in supercritical form (kg)

  • mout: cumulative mass of fluid vented (kg)

  • min: cumulative mass of fluid inserted (kg)

  • na_dot: the amount of fluid (moles) being adsorbed per second.

  • ng_dot: the first derivative of the amount of fluid in gaseous form w.r.t. time. Its unit is mol/s.

  • nl_dot: the first derivative of the amount of fluid in liquid form w.r.t. time. Its unit is mol/s

  • ns_dot: the first derivative of the amount of fluid in supercritical form w.r.t. time. Its unit is mol/s.

  • Qcoolreq_dot: the cooling power (W) required to maintain a constant pressure during refuel.

  • Qheatreq_dot: the heating power (W) required to maintain a constant pressure during discharge.

  • nout_dot: the rate at which fluid is being vented from the tank (mol/s).

  • Hout_dot: the rate at which enthalpy is taken away by fluid leaving the tank (W).

  • nin_dot: the rate at which fluid is entering the tank (mol/s).

  • Hin_dot: the rate at which enthalpy is added by fluid fluid entering the tank (W).

  • Qcooladd_dot: the user specified cooling power (W).

  • Qheatadd_dot: the user specified heating power (W).

  • Qleak_dot: the rate of heat leakage into the tank (W).

  • ma_dot: the mass of fluid (kg) being adsorbed per second.

  • mg_dot: the first derivative of the mass of fluid in gaseous form w.r.t. time. Its unit is kg/s.

  • ml_dot: the first derivative of the mass of fluid in liquid form w.r.t. time. Its unit is kg/s.

  • ms_dot: the first derivative of the mass of fluid in supercritical form w.r.t. time. Its unit is kg/s.

  • mout_dot: the rate at which fluid is being vented from the tank (kg/s).

  • min_dot: the rate at which fluid is being inserted into the tank (kg/s).

classmethod combine(sim_results_list)

Combine the results of several simulations into a single object.

Parameters:

sim_results_list ("List[SimResults]") – A list of SimResults objects from several different simulations.

Returns:

A single object containing the combined simulation results.

Return type:

SimResults