Source code for component.heat_exchanger.hex_csteff

from connector.mass_connector import MassConnector
from connector.heat_connector import HeatConnector

from component.base_component import BaseComponent

# from component.heat_exchanger.moving_boundary.simple_model.modules.U import U_Gnielinski_calibrated, U_DittusBoelter, U_Cooper_calibrater, U_Thonon

import CoolProp.CoolProp as CP



class HexCstEff(BaseComponent):
    """
    **Component**: Counterflow Heat Exchanger with Constant Effectiveness (HXEffCst)
    
    **Model**: Simplified Heat Exchanger Model with Constant Effectiveness
    
    **Description**:
    
        This model simulates a counterflow heat exchanger with a fixed effectiveness (η). It estimates the maximum possible heat transfer based on inlet conditions and applies the given effectiveness to compute the actual heat transfer rate. The model assumes a simplified configuration without discretization or detailed internal states. It is suitable for quick, steady-state evaluations in system-level models.
    
    **Assumptions**:
    
        - Steady-state operation.
        - Constant effectiveness (η) is applied across the entire heat exchanger.
        - No phase change or pressure drop effects are modeled.
        - Uniform flow distribution on both hot and cold sides.
        - Fluid properties are retrieved from CoolProp.
    
    **Connectors**:
    
        su_C (MassConnector): Mass connector for the cold-side supply.
        
        su_H (MassConnector): Mass connector for the hot-side supply.
        
        ex_C (MassConnector): Mass connector for the cold-side exhaust.
        
        ex_H (MassConnector): Mass connector for the hot-side exhaust.
        
        Q (HeatConnector): Heat transfer connector representing the total exchanged heat.
    
    **Parameters**:
    
        eta (float): Effectiveness of the heat exchanger [-].
    
    **Inputs**:
    
        fluid_H (str): Hot-side fluid.
        
        h_su_H (float): Hot-side inlet specific enthalpy [J/kg].
        
        P_su_H (float): Hot-side inlet pressure [Pa].
        
        m_dot_H (float): Hot-side mass flow rate [kg/s].
    
        fluid_C (str): Cold-side fluid.
        
        h_su_C (float): Cold-side inlet specific enthalpy [J/kg].
        
        P_su_C (float): Cold-side inlet pressure [Pa].
        
        m_dot_C (float): Cold-side mass flow rate [kg/s].
    
    **Outputs**:
    
        h_ex_C: Cold-Side Exhaust specific enthalpy at outlet [J/kg].
        
        P_ex_C: Cold-Side Exhaust pressure at outlet [Pa].
                    
        h_ex_H: Hot-Side specific enthalpy at outlet [J/kg].
        
        P_ex_H: Hot-Side pressure at outlet [Pa].
        
        Q_dot: Total heat transfer rate across the exchanger [W].

    """

    def __init__(self):
        super().__init__()
        self.su_C = MassConnector() # Working fluid supply
        self.su_H = MassConnector() # Secondary fluid supply
        self.ex_C = MassConnector()
        self.ex_H = MassConnector()

        self.Q = HeatConnector()
        self.guesses = {}

    def get_required_inputs(self):
        # Return a list of required inputs
        return['fluid_C', 'h_su_C', 'P_su_C', 'm_dot_C', 'fluid_H', 'h_su_H', 'P_su_H', 'm_dot_H']
    
    def get_required_parameters(self):
        # Return a list of required parameters
        return['eta']

    def solve(self):
        # Ensure all required checks are performed

        if self.su_H.m_dot is None: 
            self.su_H.m_dot = self.su_C.m_dot
        
        if self.su_C.m_dot is None:
            self.su_C.m_dot = self.su_H.m_dot    
    
        self.check_calculable()
        self.check_parametrized()
        
        if 'DP_c' in self.params:
            self.DP_c = self.params['DP_c']
        else:
            self.DP_c = 0
        
        if 'DP_h' in self.params:
            self.DP_h = self.params['DP_h']
        else:
            self.DP_h = 0
        
        try:
            "Define Abstract State for property calculations"
            self.AS_C = CP.AbstractState('HEOS', self.su_C.fluid)
            self.AS_H = CP.AbstractState('HEOS', self.su_H.fluid)
    
            "Define Q_dot_max through enthalpies"
            self.AS_H.update(CP.PT_INPUTS, self.su_H.p, self.su_C.T) 
            H_h_id = self.AS_H.hmass() # Ideal enthalpy computed based on cold side temperature
            self.AS_C.update(CP.PT_INPUTS, self.su_C.p, self.su_H.T)
            H_c_id = self.AS_C.hmass() # Ideal enthalpy computed based on hot side temperature
            
            Q_dot_maxh = self.su_H.m_dot*abs(H_h_id-self.su_H.h)
            Q_dot_maxc = self.su_C.m_dot*abs(H_c_id-self.su_C.h)
            
            Q_dot_max = min(Q_dot_maxh,Q_dot_maxc)
            
            "Heat Transfer Rate"
            Q_dot = self.params['eta']*Q_dot_max
    
            "Outlet states"   
            self.update_connectors(Q_dot)
            self.solved = True
            
        except:
            "Define Q_dot_max through C_dot"
            self.AS_C.update(CP.PT_INPUTS, self.su_C.p, self.su_C.T)
            cp_c = self.AS_C.cpmass()
            
            self.AS_H.update(CP.PT_INPUTS, self.su_H.p, self.su_H.T)
            cp_h = self.AS_H.cpmass()
            
            C_dot_c = self.su_C.m_dot*cp_c
            C_dot_h = self.su_H.m_dot*cp_h
            
            C_dot_min = min(C_dot_c, C_dot_h)
            Q_dot_max = C_dot_min*(self.su_H.T-self.su_C.T)
            
            "Heat Transfer Rate"
            Q_dot = self.params['eta']*Q_dot_max
            
            "Outlet states"   
            self.update_connectors(Q_dot)
            self.solved = True
            
        return

    def update_connectors(self, Q_dot):
        
        "Mass Connectors"
        self.ex_C.set_fluid(self.su_C.fluid)
        self.ex_C.set_m_dot(self.su_C.m_dot)
        self.ex_C.set_h(self.su_C.h + Q_dot/self.su_C.m_dot)
        self.ex_C.set_p(self.su_C.p - self.DP_c)

        self.ex_H.set_fluid(self.su_H.fluid)
        self.ex_H.set_m_dot(self.su_H.m_dot)
        self.ex_H.set_h(self.su_H.h - Q_dot/self.su_H.m_dot)
        self.ex_H.set_p(self.su_H.p - self.DP_h)

        "Heat conector"
        self.Q.set_Q_dot(Q_dot)

    def print_results(self):
        print("=== Heat Exchanger Results ===")
        print(f"Q: {self.Q.Q_dot}")
        print("======================")

    def print_states_connectors(self):
        print("=== Heat Exchanger States ===")
        print("Connectors:")
        print(f"  - su_C: fluid={self.su_C.fluid}, T={self.su_C.T}, p={self.su_C.p}, m_dot={self.su_C.m_dot}")
        print(f"  - su_H: fluid={self.su_H.fluid}, T={self.su_H.T}, p={self.su_H.p}, m_dot={self.su_H.m_dot}")
        print(f"  - ex_C: fluid={self.ex_C.fluid}, T={self.ex_C.T}, p={self.ex_C.p}, m_dot={self.ex_C.m_dot}")
        print(f"  - ex_H: fluid={self.ex_H.fluid}, T={self.ex_H.T}, p={self.ex_H.p}, m_dot={self.ex_H.m_dot}")
        print(f"  - Q_dot: {self.Q.Q_dot}")
        print("======================")