PEV Heat dissipation



Heat dissipation of a simple Plug-in hybrid electric vehicle during the charging process

%% PEV data set
clear all
%Geometry ESS for heat dissipation (Conductive parameters, Matlab script)
%Specific heat capacitance energy storage system (Thermal mass, Matlab script)
%Polymer heat capacitance
%Charger below 60C
%Battery charging efficiency needed
%Heat exchanger may vary between inverter and energy storage system
%Total process estimastes ~25% in heat dissipation losses what is rather

%% General PEV data
%Grid connection
P_l=1500;%Power line connection [W]

%Cooling fluid initial conditions
c_p=4200;%[J/kgK] specific heat capacitance H2O
T_i=283.15;%Initial cooling liquid temperature at inverter,
%heat exchanger inlet, and inverter case [K] 
T_ambient=300.15;%Initial ambient temperature;

%% Data inverter/charger

%Assumptions base on Delta-q QuiQ datasheet
E_inverter=0.83;%Inverter efficiency 

%Specific heat capacitance inverter
c_Al=897;%Specific heat capacitance aluminum around room temperature [J/kg K]
c_Co=385;%Specific heat capacity copper [J/kg K]
c_Fe=449;%Specific heat capacity iron [J/kg K]
c_Po=50;%Specific heat capacity of typical Polymers in conductor boards

%% Conductive heat transfer parameters for thermal path between inverter and heat exchanger

k_Al=237;%Thermal conductivity aluminum case around room temperature [W/m C]
m_case=0.1;%Case weight [kg]
w_case=0.05;%Width case [m]
A_case=0.246*0.278*0.75;%Assumed surface area of the PEV inverter/charger

w_bond=0.025;%Width bond between case plate and heat exchanger
k_bond=296;%Eutectic bond as it is in chip carriers

k_ideal=2*k_Al;%Assumed ideal thermal conductivity [W/m C];
A_ideal=2*A_case;%Assumed ideal conductive heat transfer area [m^2];

%% Cooling plate parameters

%The underlying assumption is a custom made turbo tube liquid cold plate
%adapted to the geometry of the inverter. Assumptions base on Aavid
%Thermalloy Turbo Tube Liquid Cold Plate datasheet

k_Co=401;%Thermal conductivity of copper [W/m C] used in the heat exchanger pipes
w_pipe=0.0015;%Thickness of copper pipes app. 1.5mm
Dm=0.01;%Outer diameter of tubes
L=0.75*0.278;%Effective tube length one way [m]
n=10;%number of pipes on cooling plate
A_pipes=1/3*pi*Dm*L*n; %Assumed relevant area for conductive heat transfer as app. 
%1/3 of tube surface is facing towards the inverter case

A_plate=A_case-A_pipes; %Case surface less tube diameter*number of tubes*effective 
%tube length adapted from inverter case surface
w_plate=0.05;%Assumed thickness extrusion Aluminum plate [m]

V_pipes=pi*(Dm/2)^2*n*L*0.66;%Effective Volume of pipes inside the Aluminum plate profile
V_plate=A_case*w_plate-V_pipes;%Volume Aluminum plate less spacetaken by tubes [m^3]
rho_Al=2710;%[kg/m^3] Density Aluminum plate
m_plate=rho_Al*V_plate;%Mass Aluminum plate 
A_bs_bond=2/3*A_pipes/(1/3);%Effective conductive heat transfer surface area of the bond on the backside

A_surface=A_case;%Convective heat transfer area for outside-facing cooling plates under realistic conditions
h_surface=25;%Empirical value for free convection of gases. Source: Cengel, Basics of heat transfer, 2002, S. 26

%% Heat exchange process parameters

U=1000;     %[W/m^2 K] Overall heat transfer coefficient steam condenser 
            %(Cengel, 2002, S. 673) 
A_HE=Dm*pi*(L/0.75)*n;%[m^2] Relevant area for convective heat transfer along the whole pipe length
NTU=UA/(m_dot*c_p);%Number of transferred units
E=1-exp(-NTU);%Initial heat exchanger efficiency
rho_Co=8920;%Density Copper [kg/m^3]
high_efficiency=0.7;%High efficiency option for scenario analysis

%% Energy storage system parameters

E_ess=0.9;%Energy storage system charging efficiency
m_ess=40;%Mass of a single energy storage system [kg]
c_ess=3482;%Specific heat capacitance Lithium [J/kg K]
C_ess=4900;%Energy storage system capacity [Wh] (See Hymotion, L5 Plug-in 
%Conversion module for specifications)
n_ess=PHEV;%The EV is equipped with 9 conversion modules. Whereas an efficient PHEV
%has 2 conversion modules. n_ess adapts the neccessary charging time

%% Charging patterns
DOD=0.8;%Depth of discharge 
NC_ess=DOD*C_ess*n_ess/(E_ess*E_inverter);%Relevant Net capacity energy storage system for charging
D=NC_ess*3600/P_l;%Charging duration [s]

%% Split up heat flow: 

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