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import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline
absorption 0.64
https://dumas.ccsd.cnrs.fr/dumas-00469805/document
page 116
albédo 0.33 - 0.36
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S = 25.8e-2 * 43.7e-2 # m3
m = 3.2 # kg
# Masse surfacique :
rhoS = m/S
print( rhoS )
convection libre (air) h= 5 - 25 W/m2/K
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k = 0.0262 # W/m/K, conductivité thermique
nu = 1.57e-5 # m2·s−1 , viscosité cinématique air,
alpha = 2.22e-5 # m2·s−1, diffusivité thermique
Pr = 0.708 # Prandl
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L = 4 # m, dimension caractéristique
U = 20e3/60/60 # m/s, vitesse caractéristique
print( U )
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Re = U*L/nu # Reynolds, turbulent si >3.10^5
print( Re )
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Reynolds = lambda u: u*L/nu
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# Limite turbulence
v_lim = 3e5/L*nu
print( 'vitesse limite turbulence: %f m/s '% v_lim )
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# Forcée, turbulent, Pr < 50 (cf. page 15)
h_FT = lambda u : k/L * 0.036 * Reynolds(u)**(4/5) * Pr**(1/3)
# Forcée laminaire
h_FL = lambda u : k/L * 0.664 * Reynolds(u)**(1/2) * Pr**(1/3)
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u_span_T = np.linspace( 1.0, 15, 20 ) # m/sh_FT_span = h_FT( u_span )
u_span_L = np.linspace( 0, 1.7, 20 )
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plt.figure( figsize=(10, 6) )
plt.plot( u_span_T, h_FT( u_span_T ), label='Forcée, turbulent' )
plt.plot( u_span_L, h_FL( u_span_L ), label='Forcée, laminaire' )
plt.plot( [0, 1.7], [5, 5], label='Naturelle, laminaire&turb.' )
# plt.plot( u_span_T, 6.5*u_span_T, label='Forcée, laMétéo-dec' )
plt.xlabel( 'vitesse vent m/s' )
plt.ylabel( 'h W/m2/K' );
plt.legend();
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theta = 37*np.pi/180
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deltaT = 30
L = 4 # m
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g = 9.81 #* np.cos(theta) #m/s-2
beta = 3e-3 # air, 20°C
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Gr = g*beta*deltaT*L**3/nu**2
print('Grashof: %e'% Gr )
print('Rayleight: %e'% (Gr*Pr) )
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# Plaque horizontale chauffant vers le haut
h_NTh = k/L * 0.14*(Gr*Pr)**(1/3)
print( h_NTh )
# Vertical, turbulent (Mac Adams)
h_NTv = k/L * 0.13 * (Gr*Pr)**(1/3)
print( h_NTv )
Si taille de tuile comme dim carac:
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L = 20e-2 # m
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Gr = g*beta*deltaT*L**3/nu**2
print('Grashof: %e'% Gr )
print('Rayleight: %e'% (Gr*Pr) )
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# limite de turbulence ...
# vertical :
h_NLv = k/L * 0.677* (Pr)**(1/2)/(0.95+Pr)**(1/4)*Gr**(1/4)
print( h_NLv )
# horizontale :
h_NLh = k/L * 0.54* (Pr*Gr)**(1/4)
print( h_NLh )
laine de verre
http://www.toutsurlisolation.com/Choisir-son-isolant/Les-isolants/Isolants-en-laine-minerale/Laine-de-verre
sigma = 0.030W/(m.k.) à 0.040W/(m.k)
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ep = 20e-2 # m
k = 0.035 # W/m/K
S_plafond = 2*4.59*7.94 # m2 , surface toit
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print( 'U_toit = %.3f W/K'%(ep*k*S_plafond) )
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h_vitre = 2.8 # W/ (m2.K)
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h_vitre = 2.8 # W/ (m2.K)
S_vitre = 0.6*0.8*2 + 1.2*0.8 + 0.3*0.72*4 + 0.25**2 # m2
print('surface vitrée: %.2f m^2' % S_vitre )
print( '> U_vitre : %.3f W/K'%( h_vitre*S_vitre ) )
longueur_cadres = (0.6+0.8)*4 + (1.2+0.8)*2 + 2*(0.3+0.72)*4 + 4*0.25
print( 'longueur cadres: %.1f m' % longueur_cadres )
psi = 0.016
k_bois = 0.15 + psi #
U_cadres = k_bois*longueur_cadres # W/K
print( '> U_cadres : %.3f W/K'%( U_cadres ) )
print(' ')
print( '> U_tot : %.3f W/K'%( U_cadres + h_vitre*S_vitre ) )
https://www.commeunthermicien.fr/scripts/doc/Fiche-Inertie.pdf
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# pour du béton :
rhoCp = 1400e3 # J/m3/K
k = 1.75 # W/m/K
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# Distance de pénetration dans les murs :
temps_carac = 60*60*12 # 12h
D = k/rhoCp # diffusivité
distance = np.sqrt( D*temps_carac )
print( 'Longeur carac. diff. mur: %f cm' % (distance*100) )
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surface_murs = 58 + 2*22.7
ep_utile = 0.08 # 8cm
M_mur = surface_murs*ep_utile*rhoCp
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print( 'masse thermique murs: %.2e J/K'% M_mur )
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h = 10
print( M_mur/h/60/60/24 )
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Volume_appart = 22.7 * 7.94 # m3
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# http://www.engineeringtoolbox.com/air-properties-d_156.html
rho_air = 1.2051 # kg/m3, 20°C
Cp_air = 0.005 * 1e3 # J/(kg K), 20°C
rhoCp_air = Cp_air*rho_air
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print( 'masse air appart: %f kg'% (Volume_appart*rho_air) )
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M_air = Volume_appart*rho_air*Cp_air
print( 'masse thermique air appart: %f J/K'% M_air )
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A = 1.2*0.3 # m2
v = 0.5 # m/s
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taux = ( A*v ) / Volume_appart
print( taux*60*60 )
http://www.rowenta.fr/Confort-de-la-maison/Ventilateurs/ESSENTIAL-COMPACT/p/4100000412
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q_min = 34 # m3/min +- 10%
q_min = q_min - 0.1*q_min
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taux = (q_min*60)/ Volume_appart
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print( taux )
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taux = 10 # Volume / heure
U_aeration = q_min *60*60 * rhoCp_air
print( 'U_ventilateur: %f W/K' % U_aeration )
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# http://www.ecro.fr/fr/principes-solutions/principes/taux-de-brassage-renouvellement.html
taux = 2 # V/h
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Volume_appart = 22.7 * 7.94 # m3
U_aeration = taux *Volume_appart /60/60 * rhoCp_air
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print( 'U aération nat: %f W/K' % U_aeration )
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12/2.3
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3.5*5
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