Replies: 2 comments 4 replies
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# %%
#import des bibliothèques
from tespy.components.basics.cycle_closer import CycleCloser
from tespy.networks import Network
from tespy.components import (
CycleCloser, Pipe, Pump, Valve, SimpleHeatExchanger,Splitter,Merge
)
from tespy.connections import Connection
# fluid is therminol 66 : Coolprop fluid = "T66"
Fluid='INCOMP::T66'
# https://tespy.readthedocs.io/en/main/
# %%
# table de tuyauterie
DN_Acier={
21.7:0.1295,
27.3:0.1564,
36:0.1589,
41.9:0.181,
53.9:0.2013,
69.7:0.2325,
82.5:0.2418,
107.1:0.2543,
132.5:0.288,
160.3:0.3369,
210.1:0.3686,
263:0.3637,
312.7:0.4126,
344.4:0.4009,
393.8:0.4222,
444.4:0.4242,
495.4:0.4149,
595.8:0.5002,
695.2:0.5665,
795.4:0.6372,
}
# Trouver la clé strictement supérieure
def find_DN( D):
for key in sorted(DN_Acier.keys()):
if key >= D*1000:
return key/1000, DN_Acier[key]*1000
return None, None # Si aucune clé ne correspond
# %%
# définitions du réseau
nw = Network()
nw.set_attr(
T_unit='C',
p_unit='bar',
h_unit='kJ / kg',
v_unit='m3 / h',
vol_unit='m3 / kg'
)
# central heating plant
Chaudiere = SimpleHeatExchanger('Biomasse')
cc = CycleCloser('cycle closer',printout=False)
Pompe = Pump('Pompe')
# consumer
cons=[]
val=[]
for i in range(5):
cons.append(SimpleHeatExchanger('consumer_' + str(i+1))) # Append to the list
val.append(Valve('control_valve_' + str(i+1)))
# pipes
pipe=[]
for i in range(10):
pipe.append(Pipe('Pipe_'+str(i)))
# Split & merge
sp0 = Splitter("splitter 1", num_out=2)
sp1 = Splitter("splitter 2", num_out=2)
sp2 = Splitter("splitter 3", num_out=2)
sp3 = Splitter("splitter 4", num_out=2)
me1 = Merge("merge 1", num_in=2)
me2 = Merge("merge 2", num_in=2)
me3 = Merge("merge 3", num_in=2)
me4 = Merge("merge 4", num_in=2)
# connections
c=[None]*35
#aller et consumers
c[0] = Connection(cc, "out1", Chaudiere, "in1", label="entrée chaudière")
c[1] = Connection(Chaudiere, "out1", Pompe, "in1", label="sortie chaudière")
c[2] = Connection(Pompe, "out1", pipe[0], "in1", label="sortie pompe")
c[3] = Connection(pipe[0], "out1", sp0, "in1", label="Feeder")
c[4] = Connection(sp0 , "out1", val[0] , "in1", label="4")
c[5] = Connection(val[0], "out1", cons[0], "in1", label="entrée ech0")
c[6] = Connection(cons[0] , "out1", pipe[5] , "in1", label="sortie ech0")
c[7] = Connection(sp0 , "out2", pipe[1] , "in1", label="7")
c[8] = Connection(pipe[1] , "out1", sp1 , "in1", label="8")
c[9] = Connection(sp1 , "out1", val[1] , "in1", label="9")
c[10] = Connection(val[1] , "out1", cons[1] , "in1", label="entrée ech1")
c[11] = Connection(cons[1] , "out1", me1 , "in1", label="sortie ech1")
c[12] = Connection(sp1 , "out2", pipe[2] , "in1", label="12")
c[13] = Connection(pipe[2] , "out1", sp2 , "in1", label="13")
c[14] = Connection(sp2 , "out1", val[2] , "in1", label="14")
c[15] = Connection(val[2] , "out1", cons[2] , "in1", label="entrée ech2")
c[16] = Connection(cons[2], "out1", me2 , "in1", label="sortie ech2")
c[17] = Connection(sp2 , "out2", pipe[3] , "in1", label="17")
c[18] = Connection(pipe[3] , "out1", sp3 , "in1", label="18")
c[19] = Connection(sp3 , "out1", val[3] , "in1", label="19")
c[20] = Connection(val[3], "out1", cons[3] , "in1", label="entrée ech3")
c[21] = Connection(cons[3] , "out1", me3 , "in1", label="sortie ech3")
c[22] = Connection(sp3 , "out2", pipe[4] , "in1", label="22")
c[23] = Connection(pipe[4] , "out1",val[4] , "in1", label="23")
c[24] = Connection(val[4] , "out1", cons[4] , "in1", label="entrée ech4")
c[25] = Connection( cons[4], "out1", me4 , "in1", label="sortie ech4")
#retour
c[26] = Connection(pipe[5] , "out1", me1 , "in2", label="26")
c[27] = Connection(me1 , "out1", pipe[6] , "in1", label="27")
c[28] = Connection(pipe[6] , "out1", me2 , "in2", label="28")
c[29] = Connection(me2 , "out1", pipe[7] , "in1", label="29")
c[30] = Connection(pipe[7] , "out1", me3 , "in2", label="30")
c[31] = Connection(me3 , "out1", pipe[8] , "in1", label="31")
c[32] = Connection(pipe[8] , "out1", me4 , "in2", label="32")
c[33] = Connection(me4, "out1", pipe[9] , "in1", label="33")
c[34] = Connection(pipe[9] , "out1", cc , "in1", label="34")
for i in range(35):
nw.add_conns(c[i])
# %%
# Initialisation pour premier calcul
# Tuyauteries
for i in range(10):
pipe[i].set_attr(
pr=0.9,
Q=-100, # deperdition estimées
Tamb=15,
ks = 0.00045, #rugosité
D = 'var' # cherche diametre
)
pipe[0].set_attr(L=100)
pipe[1].set_attr(L=50)
pipe[2].set_attr(L=50)
pipe[3].set_attr(L=160)
pipe[4].set_attr(L=80)
pipe[5].set_attr(L=50)
pipe[6].set_attr(L=50)
pipe[7].set_attr(L=160)
pipe[8].set_attr(L=80)
pipe[9].set_attr(L=250)
# chaudière
Chaudiere.set_attr(
# Tamb=800,
pr=1,
Q='var',
Tamb = 12,
)
# pompe
Pompe.set_attr(
eta_s=0.75,
)
# consommateurs
for i in range(5):
cons[i].set_attr(
pr = 0.93,
Tamb=200,
)
val[i].set_attr(pr='var')
cons[0].set_attr(Q=-1.9e6) # Jod
cons[1].set_attr(Q=-1.8e6) # Castor
cons[2].set_attr(Q=-3e6) # Noris
cons[3].set_attr(Q=-2.5e6) # Astérix
cons[4].set_attr(Q=-1.8e6) # Pollux
# fluide, pression et températures
c[0].set_attr( fluid={Fluid : 0},p=3) # entrée chaudière
c[1].set_attr(T=330) # sortie chaudière
c[2].set_attr(p=8)
# températures de sorties
for i in (6,11,16,21,25): # sorties échangeurs
c[i].set_attr(T=230)
#calcul
nw.solve(mode="design")
nw.print_results()
# %%
# Définition des DN normalisés / Calcul des Pertes de charge et de température
# calcul du dP pompe Réel nécessaire
for i in range(10):
dn, ka = find_DN(pipe[i].D.val)
pipe[i].set_attr(
D = dn, # Diametre normalisé
kA=ka, # perte de chaleur correspondante
pr='var',
Q='var',
)
# consommateurs
for i in range(5):
cons[i].set_attr(
# Q = -6e6,
pr = 0.98,
Tamb=200,
)
val[i].set_attr(pr='var')
# Suppression de la valeur de sortie de la pompe
c[2].set_attr(p=None)
# vanne de la sortie la plus défavorisée trés ouverte
val[4].set_attr(
pr=0.99,
)
#d éfinition de la valeur cherchée de la pompe
Pompe.set_attr(
eta_s= 0.75,
pr='var'
)
#calcul
nw.solve(mode="design",max_iter=100)
nw.print_results()
# %%
nw.save('Results_omya')
# %% [markdown]
# until here everything had worked fine.....
# %%
# Calcul avec echangeur 0 arrété
# définition de la valeur cherchée de la pompe
c[2].set_attr(p=None)
# vanne forcée pour permettre calcul
val[4].set_attr(
pr=.8,
)
# fermeture de l'echangeur 0
cons[0].set_attr(
Q = 'var',
)
# fermeture de l'echangeur 0
val[0].set_attr(
pr=0,
)
# nw.solve(mode="design",max_iter=100)
nw.solve(mode="offdesign",design_path='Results_omya',max_iter=100)
nw.print_results() |
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Hi @HaarNhoo, thank you for reaching out, I can respond to your request more thoroughly on Sunday. Models with mass flow = 0 pose challenges, you could specify a very small value for Q, that could work. Best Francesco |
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Hi, I'll wait and let you try and investigate. Thanks for your time and work |
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|
Ah, do you have fixed ambient temperature and identical temperature at inlet and outlet? If yes, the reason is, that the expression evaluates to zero inside the log, that does not work. Maybe a try except is necessary around that block. Does it happen in postprocessing or during iteration? |
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I've changed the last part of my code by # Calcul avec echangeur 0 arrété
# définition de la valeur cherchée de la pompe
c[2].set_attr(p=None)
# vanne forcée pour permettre calcul
val[4].set_attr(
pr=.8,
)
# fermeture de l'echangeur 0
cons[0].set_attr(
Q = 'var',
)
# fermeture de l'echangeur 0
c[6].set_attr(m=0.001)
# nw.solve(mode="design",max_iter=100)
nw.solve(mode="offdesign",design_path='Results_omya',max_iter=100)
nw.print_results()And it gives me this I hope this could help you. It seems to me that it would be easier to configure a network if we could force a valve to be closed. |
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Hi @HaarNhoo, an issue with steady-state systems when forcing mass flow to be zero is, that for many equations is it not necessarily clear, which part of the equation should be zero. So using a very small value should always be a good way out. There are a couple of simplifications you could take in the first step, because by making the pressure ratios and heat transfers of many of the components to be variables of the system, you make the system of equation more complex than necessary. The results of the values found in postprocessing will be the same value the newton algorithm would find during solving. # Initialisation pour premier calcul
# Tuyauteries
for i in range(10):
pipe[i].set_attr(
pr=0.9,
Q=-100, # deperdition estimées
Tamb=15,
ks = 0.00045, #rugosité
D = 'var' # cherche diametre
)
pipe[0].set_attr(L=100)
pipe[1].set_attr(L=50)
pipe[2].set_attr(L=50)
pipe[3].set_attr(L=160)
pipe[4].set_attr(L=80)
pipe[5].set_attr(L=50)
pipe[6].set_attr(L=50)
pipe[7].set_attr(L=160)
pipe[8].set_attr(L=80)
pipe[9].set_attr(L=250)
# chaudière
Chaudiere.set_attr(
# Tamb=800,
pr=1,
# Q='var',
Tamb = 12,
)
# pompe
Pompe.set_attr(
eta_s=0.75,
)
# consommateurs
for i in range(5):
cons[i].set_attr(
pr = 0.93,
Tamb=200,
)
# val[i].set_attr(pr='var')
cons[0].set_attr(Q=-1.9e6) # Jod
cons[1].set_attr(Q=-1.8e6) # Castor
cons[2].set_attr(Q=-3e6) # Noris
cons[3].set_attr(Q=-2.5e6) # Astérix
cons[4].set_attr(Q=-1.8e6) # Pollux
# fluide, pression et températures
c[0].set_attr( fluid={Fluid : 0},p=3) # entrée chaudière
c[1].set_attr(T=330) # sortie chaudière
c[2].set_attr(p=8)
# températures de sorties
for i in (6,11,16,21,25): # sorties échangeurs
c[i].set_attr(T=230)
#calcul
nw.solve(mode="design")
nw.print_results()
# %%
# Définition des DN normalisés / Calcul des Pertes de charge et de température
# calcul du dP pompe Réel nécessaire
for i in range(10):
dn, ka = find_DN(pipe[i].D.val)
pipe[i].set_attr(
D = dn, # Diametre normalisé
kA=ka, # perte de chaleur correspondante
# pr=None,
Q=None,
)
# consommateurs
for i in range(5):
cons[i].set_attr(
# Q = -6e6,
pr = 0.98,
Tamb=200,
)
# val[i].set_attr(pr='var')
# Suppression de la valeur de sortie de la pompe
c[2].set_attr(p=None)
# vanne de la sortie la plus défavorisée trés ouverte
val[4].set_attr(
pr=0.99,
)
#d éfinition de la valeur cherchée de la pompe
Pompe.set_attr(
eta_s= 0.75,
# pr='var'
)
#calcul
nw.solve(mode="design",max_iter=100)
nw.print_results()I would be interested, as to why you inputted these the way you did before (with all kinds of stuff being variables, To your issue: The function applied with c[6].set_attr(m=c[6].m.val)
cons[0].set_attr(Q=None)
nw.solve(mode="design",max_iter=100)
while True:
c[6].set_attr(m=c[6].m.val * 0.5)
cons[0].set_attr(Q=None)
nw.solve(mode="design",max_iter=100)
print(c[6].m.val_SI)So, to fix this, it would be nice to remove the part of the system you do not want to model. You can not super easily do this natively. I have to think a bit about possible solutions how to automize it. For now, you could remove the specification of the while True:
c[6].set_attr(m=c[6].m.val * 0.5)
cons[0].set_attr(Q=None)
try:
nw.solve(mode="design")
except ValueError:
break
print(c[6].m.val_SI)
c[26].set_attr(T=100)
pipe[5].set_attr(Tamb=None)
nw.solve("design") |
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Hi,
I'm new to TESPy and currently working on my first work-related project.
As you can probably tell, English isn't my first language—sorry about that!
I'm designing a heat network, as shown in the attached schematic:
I've created the network and performed an initial design to calculate the flows and diameters.
Then, I adjusted the diameters to match standard values (I might open another thread on this topic).
After redesigning the system, I got everything working
I'm pretty happy with the results so far!
Now, I would like to simulate what happens when the power demand changes in the consumer heat exchangers. Specifically, I'm trying to figure out how to:
I couldn’t find a clear solution for this in the documentation.
Either the number of parameters isn’t correct, or the solver fails with a "math error."
Any help or guidance would be greatly appreciated!
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