def __init__(self):
"""
Load up the necessary sub-structures to be filled with
the code that follows
"""
self.Compressor = CompressorClass()
#Outdoor coil is a Condenser in cooling mode and evaporator in heating mode
self.CoolingCoil = CoolingCoilClass()
self.CoolingCoil.Fins = FinInputs()
self.Pump = PumpClass()
#Add both types of internal heat exchangers
self.CoaxialIHX = CoaxialHXClass()
self.PHEIHX = PHEHXClass()
self.LineSetSupply = LineSetOptionClass()
self.LineSetReturn = LineSetOptionClass()
self.LineSetSuction = LineSetOptionClass()
self.LineSetDischarge = LineSetOptionClass()
self.LineSetLiquid = LineSetOptionClass()
#Make IHX an empty class for holding parameters common to PHE and Coaxial IHX
class struct:
pass
self.IHX = struct()
def __init__(self):
"""
Load up the necessary sub-structures to be filled with
the code that follows
"""
self.Compressor = CompressorClass()
self.CoolingCoil = CoolingCoilClass()
self.CoolingCoil.Fins = FinInputs()
self.PHEHX = PHEHXClass()
self.Pump = PumpClass()
FinsTubes.Fins.Pd = 0.001
FinsTubes.Fins.xf = 0.001
FinsTubes.Fins.t = 0.00011
FinsTubes.Fins.k_fin = 237
FinsTubes.Air.Vdot_ha = 0.5663
FinsTubes.Air.Tmean = 299.8
FinsTubes.Air.Tdb = 299.8
FinsTubes.Air.p = 101325 #Air pressure in Pa
FinsTubes.Air.RH = 0.51
FinsTubes.Air.RHmean = 0.51
FinsTubes.Air.FanPower = 438 #fan power in Watts
# Here are two equivalent methods for setting parameters
# 1. Create an empty instance of the class, then set parameters CC=CoolingCoilClass()
CC = CoolingCoilClass()
CC.Fins = FinsTubes
CC.FinsType = 'WavyLouveredFins' #Choose fin Type: 'WavyLouveredFins' or 'HerringboneFins'or 'PlainFins'
CC.Ref_g = 'Water'
CC.mdot_g = 0.15
CC.Tin_g = 278
CC.pin_g = 300000 #Refrigerant vapor pressure in Pa
CC.Verbosity = 3
CC.Calculate()
print "Method 1:"
print "Cooling Coil Q: " + str(CC.Q) + " W"
print "Cooling Coil SHR: " + str(CC.SHR) + " "
# 2. Build a dictionary of values, then use that to initialize the class
kwds = {
class SecondaryCycleClass():
def __init__(self):
"""
Load up the necessary sub-structures to be filled with
the code that follows
"""
self.Compressor = CompressorClass()
self.CoolingCoil = CoolingCoilClass()
self.CoolingCoil.Fins = FinInputs()
self.PHEHX = PHEHXClass()
self.Pump = PumpClass()
def Update(self):
'''
Update cycle class with selected HX type
Update cyle class with Abstract State
'''
if self.EvapSolver == 'Moving-Boundary':
if self.EvapType == 'Fin-tube':
self.Evaporator = EvaporatorClass()
self.Evaporator.Fins = FinInputs()
elif self.EvapType == 'Micro-channel':
raise
else:
raise
elif self.EvapSolver == 'Finite-Element':
raise
else:
raise
if self.CondSolver == 'Moving-Boundary':
if self.CondType == 'Fin-tube':
self.Condenser = CondenserClass()
self.Condenser.Fins = FinInputs()
elif self.CondType == 'Micro-channel':
self.Condenser = MicroCondenserClass()
self.Condenser.Fins = MicroFinInputs()
else:
raise
elif self.CondSolver == 'Finite-Element':
raise
else:
raise
#Abstract State
self.AS = CP.AbstractState(self.Backend, self.Ref)
if hasattr(self, 'MassFrac'):
self.AS.set_mass_fractions([self.MassFrac])
elif hasattr(self, 'VoluFrac'):
self.AS.set_volu_fractions([self.VoluFrac])
#Abstract State for SecLoopFluid
self.AS_SLF = CP.AbstractState(self.Backend_SLF, self.SecLoopFluid)
if hasattr(self, 'MassFrac_SLF'):
self.AS_SLF.set_mass_fractions([self.MassFrac_SLF])
elif hasattr(self, 'VoluFrac_SLF'):
self.AS_SLF.set_volu_fractions([self.VoluFrac_SLF])
def Calculate(self, DT_evap, DT_cond, Tin_IHX):
"""
Inputs are differences in temperature [K] between HX air inlet temperature
and the dew temperature for the heat exchanger.
Required Inputs:
DT_evap:
Difference in temperature [K] between cooling coil air inlet temperature and refrigerant dew temperature
DT_cond:
Difference in temperature [K] between condenser air inlet temperature and refrigeant dew temperature
Tin_IHX:
Inlet "glycol" temperature to IHX
"""
if self.Verbosity > 1:
print('Inputs: DTevap %7.4f DTcond %7.4f fT_IHX %7.4f' %
(DT_evap, DT_cond, Tin_IHX))
#AbstractState
AS = self.AS
#AbstractState for SecLoopFluid
AS_SLF = self.AS_SLF
"""
The coldest the glycol entering the cooling coil could be would be the
"""
self.Tdew_cond = self.Condenser.Fins.Air.Tdb + DT_cond
self.Tdew_evap = self.CoolingCoil.Fins.Air.Tdb - DT_evap
AS.update(CP.QT_INPUTS, 1.0, self.Tdew_cond)
psat_cond = AS.p() #[Pa]
AS.update(CP.QT_INPUTS, 1.0, self.Tdew_evap)
psat_evap = AS.p() #[Pa]
AS.update(CP.PQ_INPUTS, psat_evap, 0.0)
self.Tbubble_evap = AS.T() #[K]
params={ #dictionary -> key:value, e.g. 'key':2345,
'pin_r': psat_evap,
'pout_r': psat_cond,
'Tin_r': self.Tdew_evap+self.Compressor.DT_sh,
'AS': AS,
}
self.Compressor.Update(**params)
self.Compressor.Calculate()
params = {
'mdot_r': self.Compressor.mdot_r,
'Tin_r': self.Compressor.Tout_r,
'psat_r': psat_cond,
'AS': AS,
}
self.Condenser.Update(**params)
self.Condenser.Calculate()
AS.update(CP.QT_INPUTS, 0.0, self.Tbubble_evap)
hL = AS.hmass() #[J/kg]
AS.update(CP.QT_INPUTS, 1.0, self.Tdew_evap)
hV = AS.hmass() #[J/kg]
xin_r = (self.Condenser.hout_r - hL) / (hV - hL)
AS_SLF.update(CP.PT_INPUTS, 300000, Tin_IHX)
h_in = AS_SLF.hmass() #[J/kg]
params = {
'mdot_h': self.Pump.mdot_g,
'hin_h': h_in,
'hin_c': self.Condenser.hout_r,
'mdot_c': self.Compressor.mdot_r,
'pin_c': psat_evap,
'xin_c': xin_r,
'AS_c': AS,
'AS_h': AS_SLF,
}
self.PHEHX.Update(**params)
self.PHEHX.Calculate()
#Now run CoolingCoil to predict inlet glycol temperature to IHX
params = {
'mdot_g': self.Pump.mdot_g,
'Tin_g': self.PHEHX.Tout_h,
'AS_g': AS_SLF,
}
self.CoolingCoil.Update(**params)
self.CoolingCoil.Calculate()
params = {
'DP_g': self.PHEHX.DP_h + self.CoolingCoil.DP_g,
'Tin_g': self.CoolingCoil.Tout_g,
'AS_g': AS_SLF,
}
self.Pump.Update(**params)
self.Pump.Calculate()
self.Charge = self.Condenser.Charge + self.PHEHX.Charge_c
self.EnergyBalance = self.Compressor.CycleEnergyIn + self.Condenser.Q + self.PHEHX.Q
resid = np.zeros((3))
resid[0] = self.EnergyBalance
if self.ImposedVariable == 'Subcooling':
resid[1] = self.Condenser.DT_sc - self.DT_sc_target
elif self.ImposedVariable == 'Charge':
resid[1] = self.Charge - self.Charge_target
resid[2] = self.PHEHX.Q - self.CoolingCoil.Q
if self.Verbosity > 1:
print(
'Qres % 12.6e Resid2: % 12.6e ResSL %10.4f Charge %10.4f SC: %8.4f'
% (resid[0], resid[1], resid[2], self.Charge,
self.Condenser.DT_sc))
self.Capacity = self.CoolingCoil.Capacity
self.COP = self.CoolingCoil.Q / self.Compressor.W
self.COSP = self.CoolingCoil.Capacity / (
self.Compressor.W + self.Pump.W +
self.CoolingCoil.Fins.Air.FanPower +
self.Condenser.Fins.Air.FanPower)
self.SHR = self.CoolingCoil.SHR
return resid
def PreconditionedSolve(self):
# Takes the place of a lambda function since lambda functions do not
# bubble the error up properly
def OBJECTIVE(x):
return self.Calculate(x[0], x[1], x[2])
# Increase DT_evap in increments of 0.5 K until the system solves, and
# two steps cause a sign change in cycle energy balance
# Should give a starting point quite close to the "right" soluton
oldDT_evap = None
oldQresid = None
Tin_IHX = None
for DT_evap in np.linspace(12, 25, 21):
try:
#Run the cooler to get a good starting inlet temperature for IHX
self.CoolingCoil.mdot_g = self.Pump.mdot_g
self.CoolingCoil.Tin_g = self.CoolingCoil.Fins.Air.Tdb - DT_evap
self.CoolingCoil.AS_g = self.AS_SLF
self.CoolingCoil.Calculate()
Tin_IHX = self.CoolingCoil.Tout_g
resid = self.Calculate(DT_evap, 8, Tin_IHX)
except Exception, e:
if self.Verbosity > 1:
print('Failed: ', e.__str__())
raise
pass
else:
#Not set yet, first one that works
if oldQresid == None:
oldQresid = resid[0]
oldDT_evap = DT_evap
#Has been set, and sign changes, use average of old and new DT
elif oldQresid * resid[0] < 0:
DT_evap = (DT_evap + oldDT_evap) / 2
break
#Run the Newton-Raphson solver to solve the system
x = fsolve(OBJECTIVE, [DT_evap, 20, Tin_IHX])
if self.Verbosity > 1:
print('Capacity: ', self.Capacity)
print('COP: ', self.COP)
print('COP (w/ both fans): ', self.COSP)
print('SHR: ', self.SHR)
FinsTubes.Fins.Pd=0.001
FinsTubes.Fins.xf=0.001
FinsTubes.Fins.t=0.00011
FinsTubes.Fins.k_fin=237
FinsTubes.Air.Vdot_ha=0.5663
FinsTubes.Air.Tmean=299.8
FinsTubes.Air.Tdb= 299.8
FinsTubes.Air.p=101325 #Air pressure in Pa
FinsTubes.Air.RH=0.51
FinsTubes.Air.RHmean=0.51
FinsTubes.Air.FanPower=438 #fan power in Watts
# Here are two equivalent methods for setting parameters
# 1. Create an empty instance of the class, then set parameters CC=CoolingCoilClass()
CC=CoolingCoilClass()
CC.Fins = FinsTubes
CC.FinsType = 'WavyLouveredFins' #Choose fin Type: 'WavyLouveredFins' or 'HerringboneFins'or 'PlainFins'
CC.Ref_g = 'Water'
CC.mdot_g = 0.15
CC.Tin_g = 278
CC.pin_g = 300000 #Refrigerant vapor pressure in Pa
CC.Verbosity = 3
CC.Calculate()
print "Method 1:"
print "Cooling Coil Q: " + str(CC.Q) + " W"
print "Cooling Coil SHR: " + str(CC.SHR) + " "
# 2. Build a dictionary of values, then use that to initialize the class
kwds={'Fins':FinsTubes,
class SecondaryCycleClass():
def __init__(self):
"""
Load up the necessary sub-structures to be filled with
the code that follows
"""
self.Compressor = CompressorClass()
#Outdoor coil is a Condenser in cooling mode and evaporator in heating mode
self.CoolingCoil = CoolingCoilClass()
self.CoolingCoil.Fins = FinInputs()
self.Pump = PumpClass()
#Add both types of internal heat exchangers
self.CoaxialIHX = CoaxialHXClass()
self.PHEIHX = PHEHXClass()
self.LineSetSupply = LineSetOptionClass()
self.LineSetReturn = LineSetOptionClass()
self.LineSetSuction = LineSetOptionClass()
self.LineSetDischarge = LineSetOptionClass()
self.LineSetLiquid = LineSetOptionClass()
#Make IHX an empty class for holding parameters common to PHE and Coaxial IHX
class struct:
pass
self.IHX = struct()
def Update(self):
'''
Update cycle class with selected HX type
Update cycle class with Abstract State
'''
if self.EvapSolver == 'Moving-Boundary':
if self.EvapType == 'Fin-tube':
self.Evaporator = EvaporatorClass()
self.Evaporator.Fins = FinInputs()
elif self.EvapType == 'Micro-channel':
raise
else:
raise
elif self.EvapSolver == 'Finite-Element':
raise
else:
raise
if self.CondSolver == 'Moving-Boundary':
if self.CondType == 'Fin-tube':
self.Condenser = CondenserClass()
self.Condenser.Fins = FinInputs()
elif self.CondType == 'Micro-channel':
self.Condenser = MicroCondenserClass()
self.Condenser.Fins = MicroFinInputs()
else:
raise
elif self.CondSolver == 'Finite-Element':
raise
else:
raise
#Abstract State
self.AS = CP.AbstractState(self.Backend, self.Ref)
if hasattr(self, 'MassFrac'):
self.AS.set_mass_fractions([self.MassFrac])
elif hasattr(self, 'VoluFrac'):
self.AS.set_volu_fractions([self.VoluFrac])
#Abstract State for SecLoopFluid
self.AS_SLF = CP.AbstractState(self.Backend_SLF, self.SecLoopFluid)
if hasattr(self, 'MassFrac_SLF'):
self.AS_SLF.set_mass_fractions([self.MassFrac_SLF])
elif hasattr(self, 'VoluFrac_SLF'):
self.AS_SLF.set_volu_fractions([self.VoluFrac_SLF])
def OutputList(self):
"""
Return a list of parameters for this component for further output
It is a list of tuples, and each tuple is formed of items:
[0] Description of value
[1] Units of value
[2] The value itself
"""
return [
('Charge', 'kg', self.Charge),
('Condenser Subcooling', 'K', self.DT_sc),
('Primary Ref.', '-', self.Ref),
('Secondary Ref.', '-', self.SecLoopFluid),
('Imposed Variable', '-', self.ImposedVariable),
('IHX Type', '-', self.IHXType),
('COP', '-', self.COP),
('COSP', '-', self.COSP),
('Net Capacity', 'W', self.CoolingCoil.Capacity),
('Net Power', 'W', self.Power),
('SHR', '-', self.SHR),
('Condensation temp (dew)', 'K', self.Tdew_cond),
('Evaporation temp (dew)', 'K', self.Tdew_evap),
]
def Calculate(self, DT_evap, DT_cond, Tin_CC):
"""
Inputs are differences in temperature [K] between HX air inlet temperature
and the dew temperature for the heat exchanger.
Required Inputs:
DT_evap:
Difference in temperature [K] between cooling coil air inlet temperature and refrigerant dew temperature
DT_cond:
Difference in temperature [K] between condenser air inlet temperature and refrigerant dew temperature
Tin_CC:
Inlet "glycol" temperature to line set feeding cooling coil
"""
if self.Verbosity > 1:
print('Inputs: DTevap %7.4f DTcond %7.4f fT_IHX %7.4f' %
(DT_evap, DT_cond, Tin_CC))
#AbstractState
AS = self.AS
#AbstractState for SecLoopFluid
AS_SLF = self.AS_SLF
#Store the values to save on computation for later
self.DT_evap = DT_evap
self.DT_cond = DT_cond
self.Tin_CC = Tin_CC
#If the user doesn't include the Mode, set it to Air Conditioning
if not hasattr(self, 'Mode'):
self.Mode = 'AC'
if self.Mode == 'AC':
self.Tdew_cond = self.Condenser.Fins.Air.Tdb + DT_cond
self.Tdew_evap = self.CoolingCoil.Fins.Air.Tdb - DT_evap
elif self.Mode == 'HP':
self.Tdew_cond = Tin_CC + DT_cond
self.Tdew_evap = self.Evaporator.Fins.Air.Tdb - DT_evap
else:
raise ValueError('Mode must be AC or HP')
#Evaporator and condeser saturation pressures
AS.update(CP.QT_INPUTS, 1.0, self.Tdew_cond)
psat_cond = AS.p() #[Pa]
AS.update(CP.QT_INPUTS, 1.0, self.Tdew_evap)
psat_evap = AS.p() #[Pa]
#Evaporator and condeser bubble temepratures
AS.update(CP.PQ_INPUTS, psat_evap, 0.0)
self.Tbubble_evap = AS.T() #[K]
AS.update(CP.PQ_INPUTS, psat_cond, 0.0)
self.Tbubble_cond = AS.T() #[K]
#Cycle solver for 'AC' mode
if self.Mode == 'AC':
if not hasattr(self.Compressor,
'mdot_r') or self.Compressor.mdot_r < 0.00001:
# The first run of model, run the compressor just so you can get a preliminary value
# for the mass flow rate for the line set
params={ #dictionary -> key:value, e.g. 'key':2345,
'pin_r': psat_evap,
'pout_r': psat_cond,
'Tin_r': self.Tdew_evap+self.DT_sh,
'AS': AS,
}
self.Compressor.Update(**params)
self.Compressor.Calculate()
#Calculate inlet enthalpy
AS.update(CP.PT_INPUTS, psat_evap, self.Tdew_evap + self.DT_sh)
h_in = AS.hmass() #[J/kg]
params = {
'Tin': self.Tdew_evap + self.DT_sh,
'pin': psat_evap,
'hin': h_in,
'mdot': self.Compressor.mdot_r,
'AS': AS,
'Name': 'Suction Line'
}
self.LineSetSuction.Update(**params)
self.LineSetSuction.Calculate()
params = { #dictionary -> key:value, e.g. 'key':2345,
'pin_r':
psat_evap + self.DP_low,
'pout_r':
psat_cond - self.DP_high,
'Tin_r':
TrhoPhase_ph(self.AS, psat_evap, self.LineSetSuction.hout,
self.Tbubble_evap, self.Tdew_evap)[0],
'AS':
AS
}
self.Compressor.Update(**params)
self.Compressor.Calculate()
params = {
'Tin': self.Compressor.Tout_r,
'pin': psat_cond,
'hin': self.Compressor.hout_r,
'mdot': self.Compressor.mdot_r,
'AS': AS,
'Name': 'Discharge Line'
}
self.LineSetDischarge.Update(**params)
self.LineSetDischarge.Calculate()
params = {
'mdot_r': self.Compressor.mdot_r,
'Tin_r': self.Compressor.Tout_r,
'psat_r': psat_cond,
'AS': AS,
#'Oil': self.Oil,
#'shell_pressure':self.shell_pressure,
}
self.Condenser.Update(**params)
self.Condenser.Calculate()
params = {
'Tin': self.Condenser.Tout_r,
'pin': psat_cond,
'hin': self.Condenser.hout_r,
'mdot': self.Compressor.mdot_r,
'AS': AS,
'Name': 'Liquid Line'
}
self.LineSetLiquid.Update(**params)
self.LineSetLiquid.Calculate()
#Inlet enthalpy to LineSetSupply
AS_SLF.update(CP.PT_INPUTS, self.Pump.pin_g, Tin_CC)
h_in_LineSetSupply = AS_SLF.hmass() #[J/kg]
params = {
'Tin': Tin_CC,
'mdot': self.Pump.mdot_g,
'hin': h_in_LineSetSupply,
'pin': self.Pump.pin_g,
'AS': AS_SLF,
'Name': 'Supply Line'
}
self.LineSetSupply.Update(**params)
self.LineSetSupply.Calculate()
#Now run CoolingCoil to predict inlet glycol temperature to IHX
params = {
'mdot_g': self.Pump.mdot_g,
'Tin_g': self.LineSetSupply.Tout,
'pin_g': self.CoolingCoil.pin_g,
'AS_g': AS_SLF
}
self.CoolingCoil.Update(**params)
self.CoolingCoil.Calculate()
#Inlet enthalpy to LineSetReturn
AS_SLF.update(CP.PT_INPUTS, self.Pump.pin_g,
self.CoolingCoil.Tout_g)
h_in_LineSetReturn = AS_SLF.hmass() #[J/kg]
params = {
'Tin': self.CoolingCoil.Tout_g,
'mdot': self.Pump.mdot_g,
'hin': h_in_LineSetReturn,
'pin': self.CoolingCoil.pin_g,
'AS': AS_SLF,
'Name': 'Return Line'
}
self.LineSetReturn.Update(**params)
self.LineSetReturn.Calculate()
if self.IHXType == 'Coaxial':
params = {
'mdot_g': self.Pump.mdot_g,
'Tin_g': self.CoolingCoil.Tout_g,
'pin_g': self.Pump.pin_g,
'AS_g': AS_SLF,
'pin_r': psat_evap,
'hin_r': self.LineSetLiquid.hout,
'AS_r': AS,
'mdot_r': self.Compressor.mdot_r,
}
self.CoaxialIHX.Update(**params)
self.CoaxialIHX.Calculate()
self.IHX.Charge_r = self.CoaxialIHX.Charge_r
self.IHX.Q = self.CoaxialIHX.Q
self.IHX.Tout_g = self.CoaxialIHX.Tout_g
self.IHX.DP_g = self.CoaxialIHX.DP_g
self.IHX.hout_r = self.CoaxialIHX.hout_r
self.IHX.Tout_r = self.CoaxialIHX.Tout_r
self.IHX.DP_r = self.CoaxialIHX.DP_r
if hasattr(self, 'PHEIHX'):
del self.PHEIHX
elif self.IHXType == 'PHE':
#Inlet enthalpy to PHEIHX
AS_SLF.update(CP.PT_INPUTS, self.PHEIHX.pin_h,
self.CoolingCoil.Tout_g)
h_in_PHEIHX = AS_SLF.hmass() #[J/kg]
params = {
'mdot_h': self.Pump.mdot_g,
'hin_h': h_in_PHEIHX,
'pin_h': self.PHEIHX.pin_h,
'AS_h': AS_SLF,
'mdot_c': self.Compressor.mdot_r,
'pin_c': psat_evap,
'hin_c': self.LineSetLiquid.hout,
'AS_c': AS
}
self.PHEIHX.Update(**params)
self.PHEIHX.Calculate()
self.IHX.Charge_r = self.PHEIHX.Charge_c
self.IHX.Q = self.PHEIHX.Q
self.IHX.Tout_g = self.PHEIHX.Tout_h
self.IHX.DP_g = self.PHEIHX.DP_h
self.IHX.DP_r = self.PHEIHX.DP_c
self.IHX.hout_r = self.PHEIHX.hout_c
self.IHX.Tout_r = self.PHEIHX.Tout_c
if hasattr(self, 'CoaxialIHX'):
del self.CoaxialIHX
params = {
'DP_g':
self.IHX.DP_g + self.CoolingCoil.DP_g + self.LineSetSupply.DP +
self.LineSetReturn.DP,
'Tin_g':
self.CoolingCoil.Tout_g,
'pin_g':
self.Pump.pin_g,
'AS_g':
AS_SLF,
}
self.Pump.Update(**params)
self.Pump.Calculate()
self.Charge = self.Compressor.Charge + self.Condenser.Charge + self.IHX.Charge_r + self.LineSetSuction.Charge + self.LineSetDischarge.Charge + self.LineSetLiquid.Charge
self.EnergyBalance = self.Compressor.CycleEnergyIn + self.Condenser.Q + self.IHX.Q + self.LineSetSuction.Q + self.LineSetDischarge.Q + self.LineSetLiquid.Q
#Calculate properties:
AS.update(CP.QT_INPUTS, 0.0, self.Tbubble_cond)
h_L = AS.hmass() #[J/kg]
cp_L = AS.cpmass() #[J/kg-K]
AS.update(CP.PT_INPUTS, psat_cond,
self.Tbubble_cond - self.DT_sc_target)
h_target = AS.hmass() #[J/kg]
self.DT_sc = (h_L - self.Condenser.hout_r) / cp_L
deltaH_sc = self.Compressor.mdot_r * (h_L - h_target)
resid = np.zeros((3))
resid[0] = self.Compressor.mdot_r * (self.IHX.hout_r -
self.LineSetSuction.hin)
if self.ImposedVariable == 'Subcooling':
resid[1] = self.Condenser.DT_sc - self.DT_sc_target
elif self.ImposedVariable == 'Charge':
resid[1] = self.Charge - self.Charge_target
# resid[2]=self.IHX.Q-self.CoolingCoil.Q+self.Pump.W
self.residSL = self.IHX.Q - self.CoolingCoil.Q + self.Pump.W + self.LineSetSupply.Q + self.LineSetReturn.Q
resid[2] = self.residSL
if self.Verbosity > 7:
print('Wcomp % 12.6e Qcond: % 12.6e QPHE %10.4f ' %
(self.Compressor.W, self.Condenser.Q, self.IHX.Q))
if self.Verbosity > 1:
print(
'Qres % 12.6e Resid2: % 12.6e ResSL %10.4f Charge %10.4f SC: %8.4f'
% (resid[0], resid[1], self.residSL, self.Charge,
self.Condenser.DT_sc))
self.Capacity = self.CoolingCoil.Capacity
self.COP = self.CoolingCoil.Q / self.Compressor.W
self.COSP = self.CoolingCoil.Capacity / (
self.Compressor.W + self.Pump.W +
self.CoolingCoil.Fins.Air.FanPower +
self.Condenser.Fins.Air.FanPower)
self.SHR = self.CoolingCoil.SHR
self.Power = self.Compressor.W + self.Pump.W + self.CoolingCoil.Fins.Air.FanPower + self.Condenser.Fins.Air.FanPower
self.DP_high_Model = self.Condenser.DP_r + self.LineSetDischarge.DP + self.LineSetLiquid.DP #[Pa]
self.DP_low_Model = self.IHX.DP_r + self.LineSetSuction.DP #[Pa]
#Cycle solver for 'HP' mode
elif self.Mode == 'HP':
if psat_evap + self.DP_low < 0:
raise ValueError('Compressor inlet pressure less than zero [' +
str(psat_evap + self.DP_low) +
' Pa] - is low side pressure drop too high?')
if not hasattr(self.Compressor,
'mdot_r') or self.Compressor.mdot_r < 0.00001:
# The first run of model, run the compressor just so you can get a preliminary value
# for the mass flow rate for the line set
params={ #dictionary -> key:value, e.g. 'key':2345,
'pin_r': psat_evap,
'pout_r': psat_cond,
'Tin_r': self.Tdew_evap+self.DT_sh,
'AS': AS,
}
self.Compressor.Update(**params)
self.Compressor.Calculate()
#Calculate inlet enthalpy
AS.update(CP.PT_INPUTS, psat_evap, self.Tdew_evap + self.DT_sh)
h_in = AS.hmass() #[J/kg]
params = {
'Tin': self.Tdew_evap + self.DT_sh,
'pin': psat_evap,
'hin': h_in,
'mdot': self.Compressor.mdot_r,
'AS': AS,
'Name': 'Suction Line'
}
self.LineSetSuction.Update(**params)
self.LineSetSuction.Calculate()
params = { #dictionary -> key:value, e.g. 'key':2345,
'pin_r':
psat_evap + self.DP_low,
'pout_r':
psat_cond - self.DP_high,
'Tin_r':
TrhoPhase_ph(self.AS, psat_evap, self.LineSetSuction.hout,
self.Tbubble_evap, self.Tdew_evap)[0],
'AS':
AS
}
self.Compressor.Update(**params)
self.Compressor.Calculate()
params = {
'Tin': self.Compressor.Tout_r,
'pin': psat_cond,
'hin': self.Compressor.hout_r,
'mdot': self.Compressor.mdot_r,
'AS': AS,
'Name': 'Discharge Line'
}
self.LineSetDischarge.Update(**params)
self.LineSetDischarge.Calculate()
#Inlet enthalpy to LineSetSupply
AS_SLF.update(CP.PT_INPUTS, self.Pump.pin_g, Tin_CC)
h_in_LineSetSupply = AS_SLF.hmass() #[J/kg]
params = {
'Tin': Tin_CC,
'mdot': self.Pump.mdot_g,
'hin': h_in_LineSetSupply,
'AS': AS_SLF,
'Name': 'Supply Line'
}
self.LineSetSupply.Update(**params)
self.LineSetSupply.Calculate()
#Now run CoolingCoil to predict inlet glycol temperature to IHX
params = {
'mdot_g': self.Pump.mdot_g,
'Tin_g': self.LineSetSupply.Tout,
'pin_g': self.PHEIHX.pin_c,
'AS_g': AS_SLF
}
self.CoolingCoil.Update(**params)
self.CoolingCoil.Calculate()
#Inlet enthalpy to LineSetReturn
AS_SLF.update(CP.PT_INPUTS, self.Pump.pin_g,
self.CoolingCoil.Tout_g)
h_in_LineSetReturn = AS_SLF.hmass() #[J/kg]
params = {
'Tin': self.CoolingCoil.Tout_g,
'mdot': self.Pump.mdot_g,
'hin': h_in_LineSetReturn,
'AS': AS_SLF,
'Name': 'Return Line'
}
self.LineSetReturn.Update(**params)
self.LineSetReturn.Calculate()
#Inlet enthalpy to PHEIHX
AS_SLF.update(CP.PT_INPUTS, self.PHEIHX.pin_c,
self.LineSetReturn.Tout)
h_in_PHEIHX = AS_SLF.hmass() #[J/kg]
params = {
'mdot_h': self.Compressor.mdot_r,
'hin_h': self.LineSetDischarge.hout,
'pin_h': psat_cond,
'AS_h': AS,
'mdot_c': self.Pump.mdot_g,
'hin_c': h_in_PHEIHX,
'pin_c': self.Pump.pin_g,
'AS_c': AS_SLF,
}
self.PHEIHX.Update(**params)
self.PHEIHX.Calculate()
params = {
'Tin': self.PHEIHX.Tout_h,
'pin': psat_cond,
'hin': self.PHEIHX.hout_h,
'mdot': self.Compressor.mdot_r,
'AS': AS,
'Name': 'Liquid Line'
}
self.LineSetLiquid.Update(**params)
self.LineSetLiquid.Calculate()
params = {
'mdot_r': self.Compressor.mdot_r,
'psat_r': psat_evap,
'hin_r': self.LineSetLiquid.hout,
'AS': AS,
}
self.Evaporator.Update(**params)
self.Evaporator.Calculate()
params = {
'DP_g':
self.PHEIHX.DP_c + self.CoolingCoil.DP_g +
self.LineSetSupply.DP + self.LineSetReturn.DP,
'Tin_g':
self.CoolingCoil.Tout_g,
'pin_g':
self.Pump.pin_g,
'AS_g':
AS_SLF
}
self.Pump.Update(**params)
self.Pump.Calculate()
self.Charge = self.Compressor.Charge + self.Evaporator.Charge + self.PHEIHX.Charge_h + self.LineSetSuction.Charge + self.LineSetDischarge.Charge + self.LineSetLiquid.Charge
#Calculate properties:
AS.update(CP.QT_INPUTS, 0.0, self.Tbubble_cond)
h_L = AS.hmass() #[J/kg]
cp_L = AS.cpmass() #[J/kg-K]
AS.update(CP.PT_INPUTS, psat_cond,
self.Tbubble_cond - self.DT_sc_target)
h_target = AS.hmass() #[J/kg]
#Calculate an effective subcooling amount by deltah/cp_satL
#Can be positive or negative (negative is quality at outlet
self.DT_sc = self.PHEIHX.DT_sc_h #(PropsSI('H','T',self.Tbubble_cond,'Q',0,self.Ref)-self.PHEIHX.hout_h)/(PropsSI('C','T',self.Tbubble_cond,'Q',0,self.Ref)) #*1000 #*1000
deltaH_sc = self.Compressor.mdot_r * (h_L - h_target)
resid = np.zeros((3))
resid[0] = self.Compressor.mdot_r * (self.Evaporator.hout_r -
self.LineSetSuction.hin)
if self.ImposedVariable == 'Subcooling':
resid[1] = self.DT_sc - self.DT_sc_target
elif self.ImposedVariable == 'Charge':
resid[1] = self.Charge - self.Charge_target
self.residSL = self.PHEIHX.Q + self.CoolingCoil.Q + self.Pump.W + self.LineSetSupply.Q + self.LineSetReturn.Q
resid[2] = self.residSL
if self.Verbosity > 1:
print(
'Qres % 12.6e Resid2: % 12.6e ResSL %10.4f Charge %10.4f SC: %8.4f'
% (resid[0], resid[1], self.residSL, self.Charge,
self.DT_sc))
self.Capacity = -self.CoolingCoil.Q + self.CoolingCoil.Fins.Air.FanPower
self.COP = -self.CoolingCoil.Q / self.Compressor.W
self.COSP = self.Capacity / (self.Compressor.W + self.Pump.W +
self.CoolingCoil.Fins.Air.FanPower +
self.Evaporator.Fins.Air.FanPower)
self.Power = self.Compressor.W + self.Pump.W + self.CoolingCoil.Fins.Air.FanPower + self.Evaporator.Fins.Air.FanPower
self.SHR = -self.CoolingCoil.SHR
self.DP_high_Model = self.PHEIHX.DP_h + self.LineSetDischarge.DP + self.LineSetLiquid.DP #[Pa]
self.DP_low_Model = self.Evaporator.DP_r + self.LineSetSuction.DP #[Pa]
self.DT_evap = DT_evap
self.DT_cond = DT_cond
return resid
def PreconditionedSolve(self, PrecondValues=None):
'''
PrecondValues = dictionary of values DT_evap, DT_cond and Tin_CC
'''
def OBJECTIVE(x):
"""
Takes the place of a lambda function since lambda functions do not bubble error properly
"""
return self.Calculate(x[0], x[1], x[2])
def OBJECTIVE2(x, Tin):
"""
Takes the place of a lambda function since lambda functions do not bubble error properly
"""
return self.Calculate(x[0], x[1], Tin)
def OBJECTIVE_SL(Tin_CC):
"""
Objective function for the inner loop of the vapor compression system
Using the MultiDimNewtRaph function will re-evaluate the Jacobian at
every step. Slower, but more robust since the solution surfaces aren't
smooth enough
Note: This function is not currently used!
"""
x = MultiDimNewtRaph(OBJECTIVE2, [self.DT_evap, self.DT_cond],
args=(Tin_CC, ))
# Update the guess values for Delta Ts starting
# at the third step (after at least one update away
# from the boundaries)
if self.OBJ_SL_counter >= 0:
self.DT_evap = x[0]
self.DT_cond = x[1]
pass
self.OBJ_SL_counter += 1
return self.residSL
def PrintDPs():
print('DP_LP :: Input:', self.DP_low, 'Pa / Model calc:',
self.DP_low_Model, 'Pa')
print('DP_HP :: Input:', self.DP_high, 'Pa / Model calc:',
self.DP_high_Model, 'Pa')
#Some variables need to be initialized
self.DP_low = 0 #The actual low-side pressure drop to be used in Pa
self.DP_high = 0 #The actual low-side pressure drop to be used in Pa
self.OBJ_SL_counter = 0
#Run the preconditioner to get guess values for the temperatures
if PrecondValues is None:
self.DT_evap, self.DT_cond, Tin_CC = SecondaryLoopPreconditioner(
self)
else:
self.DT_evap = PrecondValues['DT_evap']
self.DT_cond = PrecondValues['DT_cond']
Tin_CC = PrecondValues['Tin_CC']
#Remove the other, non-used IHX class if found
if self.IHXType == 'PHE':
if hasattr(self, 'CoaxialIHX'):
del self.CoaxialIHX
else:
if hasattr(self, 'PHEIHX'):
del self.PHEIHX
#Remove the condenser if in heating mode and condenser found
if self.Mode == 'HP':
if hasattr(self, 'Condenser'):
del self.Condenser
iter = 1
max_error_DP = 999
#Outer loop with a more relaxed convergence criterion
while max_error_DP > 0.5:
iter_inner = 1
#Inner loop to determine pressure drop for high and low sides
while max_error_DP > 0.05 and iter_inner < 10:
#Run to calculate the pressure drop as starting point
OBJECTIVE([self.DT_evap, self.DT_cond, Tin_CC])
#Calculate the max error
max_error_DP = max([
abs(self.DP_low_Model - self.DP_low),
abs(self.DP_high_Model - self.DP_high)
])
if self.Verbosity > 0:
PrintDPs()
print('Max pressure drop error [inner loop] is',
max_error_DP, 'Pa')
#Update the pressure drop terms
self.DP_low = self.DP_low_Model #/1000
self.DP_high = self.DP_high_Model #/1000
iter_inner += 1
if self.Verbosity > 0:
print("Done with the inner loop on pressure drop")
# Use Newton-Raphson solver
(self.DT_evap, self.DT_cond,
Tin_CC) = MultiDimNewtRaph(OBJECTIVE,
[self.DT_evap, self.DT_cond, Tin_CC],
dx=0.1)
#Calculate the error
max_error_DP = max([
abs(self.DP_low_Model - self.DP_low),
abs(self.DP_high_Model - self.DP_high)
])
if self.Verbosity > 0:
PrintDPs()
print('Max pressure drop error [outer loop] is', max_error_DP,
'Pa')
if self.Verbosity > 1:
print('Capacity: ', self.Capacity)
print('COP: ', self.COP)
print('COP (w/ both fans): ', self.COSP)
print('SHR: ', self.SHR)
print('-------------------------------------')
print(' Simulation Completed ')
print('-------------------------------------')
return