REFPROP connector

REFPROP connector is a tools developed by the SERG research group of the University of Florence for launching REFPROP calculation and retrieving results from python.

In order to use the code you must have both REFPROP and the REFPROP wrappers for Python installed and properly working.

The scope of this library is to make the usage of the refprop wrappers simpler.

The beta version can be downloaded using PIP:

pip install REFPROP_connector

Once the installation has been completed the user can import the tool and initialize the connector itself.

from REFPROPConnector import ThermodynamicPoint

tp = ThermodynamicPoint(["air"], [1.])

An important aspects to keep in mind for the initialization:

• A file-dialog could appear the first time that the connector is imported asking the user to select the REFPROP installation folder (usually it's "C:\Program Files (x86)\REFPROP"). Once the executable path has been selected, the program will keep it in memory in order to avoid a new appearance of the file-dialog. The stored executable can be modified calling the following function:

from REFPROPConnector import retreive_RP_exec

retreive_RP_exec()

Each ThermodynamicPoint class instance represent a thermodynamic state, hence you had to provide at least two indipendent state variables in order to calculate the others.

from REFPROPConnector import ThermodynamicPoint

tp = ThermodynamicPoint(["water"], [1.])

tp.set_variable("P", 0.101325)     # P in MPa (ambient pressure)
tp.set_variable("Q", 0.5)          # vapour quality for multiphase condition

T_sat = tp.get_variable("T")       # saturation temperature in celsius (100 °C)

AbstractThermodynamicPoint is a class that can be overwritten in order to perform some calculation once both independent state variable have been set. It can be useful for example for the evaluation of the reynolds number for a fluid flowing in a pipe.

from REFPROPConnector import AbstractThermodynamicPoint, RefPropHandler
import numpy as np


class TubeSection(AbstractThermodynamicPoint):

    def __init__(self, diam, flow_rate):
        
        self.diam = diam
        self.area = np.pi * np.power(diam / 2, 2)
        self.flow_rate = flow_rate
        self.Re = 0.
        
        refprop = RefPropHandler(["air"], [1])

        super().__init__(refprop)

    def other_calculation(self):
        
        mu = self.get_variable("mu") / (10 ** 6)  # conversion uPa*s -> Pa*s
        self.Re = self.flow_rate * self.diam / (self.area * mu)

if __name__ == "__main__":

    section = TubeSection(0.5, 1)
    
    """
    
        The following line will return 0. as the function "other_calculation" 
        is called only when 2 independent state variable is provided 
        
    """
    print(section.get_variable("Re"))   
    
    section.set_variable("P", 0.5)
    section.set_variable("T", 20)
    
    """
    
        The following line will return the actual Reynolds number
        
    """
    print(section.get_variable("Re"))

Variable that can be calculated can be listed using list_properties method from both ThermodynamicPoint and AbstractThermodynamicPoint (the name is not case-sensitive). Finally, user can also select the unit system to be used in the calculation, a list of possible unit system can be revived calling the method list_unit_systems() (current unit_system will be highlighted):

from REFPROPConnector import ThermodynamicPoint

tp = ThermodynamicPoint(["water"], [1.], unit_system="MASS BASE SI")
tp.list_properties()
tp.list_unit_systems()

Defaul unit system is SI with C

For other information please contact: pietro.ungar@unifi.it

-------------------------- !!! THIS IS A BETA VERSION !!! --------------------------

please report any bug or problems in the installation to pietro.ungar@unifi.it
for further information visit: https://tinyurl.com/SERG-3ETool