def Validate(self):
"""
Check that all required fields are included, and no extra fields not listed here are added
This is quite strict, but for the best to avoid typos
"""
reqFields = [('RH', float, 0, 1),
('Tdb', float, -80 + 273.15, 200 + 273.15),
('FanPower', float, 0, 4000), ('p', float, 0.01, 10000),
('Vdot_ha', float, 0.001, 10)]
optFields = ['RHmean', 'Tmean']
d = dict(self.Air.__dict__) #The current values
ValidateFields(d, reqFields, optFields)
reqFields = [('FPI', float, 0.1, 100), ('Pd', float, 0.000001, 0.1),
('xf', float, 0.000001, 0.1), ('t', float, 0.00001, 0.01),
('k_fin', float, 0.01, 10000)]
optFields = None
d = dict(self.Fins.__dict__) #The current values
ValidateFields(d, reqFields, optFields)
reqFields = [('NTubes_per_bank', int, 0.1, 100),
('Ncircuits', int, 1, 50), ('Nbank', float, 1, 50),
('Ltube', float, 0.001, 10), ('ID', float, 0.0001, 1),
('OD', float, 0.0001, 1), ('Pl', float, 0.0001, 1),
('Pt', float, 0.0001, 1)]
optFields = None
d = dict(self.Tubes.__dict__) #The current values
ValidateFields(d, reqFields, optFields)
def Initialize(self):
#Input validation the first call of Initialize
if False:#not hasattr(self,'IsValidated'):
self.Fins.Validate()
reqFields=[
('Ref',str,None,None),
('psat_r',float,0.001,100000000),
('Fins',IsFinsClass,None,None),
('FinsType',str,None,None),
('hin_r',float,-100000,10000000),
('mdot_r',float,0.000001,10),
]
optFields=['Verbosity']
d=self.__dict__ #Current fields in model
ValidateFields(d,reqFields,optFields)
self.IsValidated=True
# Retrieve some parameters from nested structures
# for code compactness
self.ID=self.Fins.Tubes.ID
self.OD=self.Fins.Tubes.OD
self.Ltube=self.Fins.Tubes.Ltube
self.NTubes_per_bank=self.Fins.Tubes.NTubes_per_bank
self.Nbank=self.Fins.Tubes.Nbank
self.Ncircuits=self.Fins.Tubes.Ncircuits
self.Tin_a=self.Fins.Air.Tdb
# Calculate an effective length of circuit if circuits are
# not all the same length
TotalLength=self.Ltube*self.NTubes_per_bank*self.Nbank
self.Lcircuit=TotalLength/self.Ncircuits
# Wetted area on the refrigerant side
self.A_r_wetted=self.Ncircuits*pi*self.ID*self.Lcircuit
self.V_r=self.Ncircuits*self.Lcircuit*pi*self.ID**2/4.0
#Average mass flux of refrigerant in circuit
self.G_r = self.mdot_r/(self.Ncircuits*pi*self.ID**2/4.0) #[kg/m^2-s]
## Bubble and dew temperatures (same for fluids without glide)
self.Tbubble_r=PropsSI('T','P',self.psat_r,'Q',0,self.Ref)
self.Tdew_r=PropsSI('T','P',self.psat_r,'Q',1,self.Ref)
## Mean temperature for use in HT relationships
self.Tsat_r=(self.Tbubble_r+self.Tdew_r)/2
# Latent heat
self.h_fg=(PropsSI('H','T',self.Tdew_r,'Q',1.0,self.Ref)-PropsSI('H','T',self.Tbubble_r,'Q',0.0,self.Ref))*1. #*1000. #[J/kg]
self.Fins.Air.RHmean=self.Fins.Air.RH
#Update with user FinType
if self.FinsType == 'WavyLouveredFins':
WavyLouveredFins(self.Fins)
elif self.FinsType == 'HerringboneFins':
HerringboneFins(self.Fins)
elif self.FinsType == 'PlainFins':
PlainFins(self.Fins)
self.mdot_ha=self.Fins.mdot_ha #[kg_ha/s]
self.mdot_da=self.Fins.mdot_da #[kg_da/s]
def Initialize(self):
#Input validation the first call of Initialize
if False:#not hasattr(self,'IsValidated'):
self.Fins.Validate()
reqFields=[
('Ref',str,None,None),
('psat_r',float,1e-6,100000),
('Fins',IsFinsClass,None,None),
('hin_r',float,-100000,10000000),
('mdot_r',float,0.000001,10),
]
optFields=['Verbosity']
d=self.__dict__ #Current fields in model
ValidateFields(d,reqFields,optFields)
self.IsValidated=True
# Retrieve some parameters from nested structures
# for code compactness
self.ID=self.Fins.Tubes.ID
self.OD=self.Fins.Tubes.OD
self.Ltube=self.Fins.Tubes.Ltube
self.NTubes_per_bank=self.Fins.Tubes.NTubes_per_bank
self.Nbank=self.Fins.Tubes.Nbank
self.Ncircuits=self.Fins.Tubes.Ncircuits
self.Tin_a=self.Fins.Air.Tdb
# Calculate an effective length of circuit if circuits are
# not all the same length
TotalLength=self.Ltube*self.NTubes_per_bank*self.Nbank
self.Lcircuit=TotalLength/self.Ncircuits
# Wetted area on the refrigerant side
self.A_r_wetted=self.Ncircuits*pi*self.ID*self.Lcircuit
self.V_r=self.Ncircuits*self.Lcircuit*pi*self.ID**2/4.0
#Average mass flux of refrigerant in circuit
self.G_r = self.mdot_r/(self.Ncircuits*pi*self.ID**2/4.0) #[kg/m^2-s]
"""
Tsat() is a relatively slow function since it does a Dekker solve
over the full two-phase region. So store the value in order to cut
down on computational work.
"""
## Bubble and dew temperatures (same for fluids without glide)
self.Tbubble_r=Props('T','P',self.psat_r,'Q',0,self.Ref)
self.Tdew_r=Props('T','P',self.psat_r,'Q',1,self.Ref)
## Mean temperature for use in HT relationships
self.Tsat_r=(self.Tbubble_r+self.Tdew_r)/2
# Latent heat
self.h_fg=(Props('H','T',self.Tdew_r,'Q',1.0,self.Ref)-Props('H','T',self.Tbubble_r,'Q',0.0,self.Ref))*1000. #[J/kg]
self.Fins.Air.RHmean=self.Fins.Air.RH
self.Fins.h_tp_tuning= self.h_tp_tuning #pass tuning factor
WavyLouveredFins(self.Fins)
self.mdot_ha=self.Fins.mdot_ha #[kg_ha/s]
self.mdot_da=self.Fins.mdot_da #[kg_da/s]
def Validate(self):
"""
Check that all required fields are included, and no extra fields not listed here are added
This is quite strict, but for the best to avoid typos
"""
reqFields = [('RH', float, 0, 1),
('Tdb', float, -80 + 273.15, 200 + 273.15),
('FanPower', float, 0, 4000), ('p', float, 10, 10000000),
('Vdot_ha', float, 0.001, 10)]
optFields = ['RHmean', 'Tmean']
d = dict(self.Air.__dict__) #The current values
ValidateFields(d, reqFields, optFields)
reqFields = [('FPI', float, 0.1, 100), ('Lf', float, 0.0001, 1),
('t', float, 0.00001, 0.01),
('k_fin', float, 0.01, 10000)]
optFields = None
d = dict(self.Fins.__dict__) #The current values
ValidateFields(d, reqFields, optFields)
reqFields = [('NTubes', float, 0.1, 100), ('Nbank', float, 1, 50),
('Npass', float, 1, 50), ('Nports', float, 1, 50),
('Ltube', float, 0.001, 10), ('Td', float, 0.0001, 1),
('Ht', float, 0.0001, 1), ('b', float, 0.0001, 1),
('tw', float, 0.00001, 0.01),
('twp', float, 0.00001, 0.01),
('beta', float, 0.00001, 100)]
optFields = None
d = dict(self.Tubes.__dict__) #The current values
ValidateFields(d, reqFields, optFields)
reqFields = [
('Lalpha', float, 1, 89),
('lp', float, 0.0001, 1),
]
optFields = ['Llouv']
d = dict(self.Louvers.__dict__) #The current values
ValidateFields(d, reqFields, optFields)
def Calculate(self):
#Only validate the first time
if not hasattr(self, 'IsValidated'):
self.Fins.Validate()
reqFields = [
('Ref', str, None, None),
('Fins', IsFinsClass, None, None),
('FinsType', str, None, None),
('mdot_r', float, 0.00001, 20),
('Tin_r', float, 200, 500),
('psat_r', float, 0.01, 20000000
) #0.00001,20000 changed to 0.01,20000000
]
optFields = ['Verbosity']
ValidateFields(self.__dict__, reqFields, optFields)
self.IsValidated = True
# Retrieve some parameters from nested structures
# for code compactness
self.ID = self.Fins.Tubes.ID
self.OD = self.Fins.Tubes.OD
self.Ltube = self.Fins.Tubes.Ltube
self.NTubes_per_bank = self.Fins.Tubes.NTubes_per_bank
self.Nbank = self.Fins.Tubes.Nbank
self.Ncircuits = self.Fins.Tubes.Ncircuits
self.Tin_a = self.Fins.Air.Tdb
## Bubble and dew temperatures (same for fluids without glide)
self.Tbubble = PropsSI('T', 'P', self.psat_r, 'Q', 0.0, self.Ref)
self.Tdew = PropsSI('T', 'P', self.psat_r, 'Q', 1.0, self.Ref)
# Calculate an effective length of circuit if circuits are
# not all the same length
TotalLength = self.Ltube * self.NTubes_per_bank * self.Nbank
self.Lcircuit = TotalLength / self.Ncircuits
self.V_r = pi * self.ID**2 / 4.0 * self.Lcircuit * self.Ncircuits
self.A_r_wetted = pi * self.ID * self.Ncircuits * self.Lcircuit
self.G_r = self.mdot_r / (self.Ncircuits * pi * self.ID**2 / 4.0)
#Definitely have a superheated portion
self._Superheat_Forward()
#Maybe have a full two-phase section
#First try to run with a full two-phase section from quality of 1 to quality of 0
self._TwoPhase_Forward()
#If we have already used too much of the HX (max possible sum of w is 1.0)
if self.w_2phase + self.w_superheat > 1:
#There is no subcooled portion, solve for outlet quality
brentq(self._TwoPhase_Forward, 0.0000001, 0.9999999)
#Zero out all the subcooled parameters
self.Q_subcool = 0.0
self.DP_r_subcool = 0.0
self.Charge_subcool = 0.0
self.w_subcool = 0.0
self.h_r_subcool = 0.0
self.existsSubcooled = False
else:
#By definition then we have a subcooled portion, solve for it
self.existsSubcooled = True
self._Subcool_Forward()
#Overall calculations
self.Q = self.Q_superheat + self.Q_2phase + self.Q_subcool
self.DP_r = self.DP_r_superheat + self.DP_r_2phase + self.DP_r_subcool
self.Charge = self.Charge_2phase + self.Charge_subcool + self.Charge_superheat
self.sin_r = PropsSI('S', 'T', self.Tin_r, 'P', self.psat_r,
self.Ref) #*1000
if self.existsSubcooled == True:
self.hout_r = PropsSI('H', 'T', self.Tout_r, 'P', self.psat_r,
self.Ref) #*1000
self.sout_r = PropsSI('S', 'T', self.Tout_r, 'P', self.psat_r,
self.Ref) #*1000
else:
self.Tout_r = self.xout_2phase * self.Tdew + (
1 - self.xout_2phase) * self.Tbubble
self.hout_r = PropsSI(
'H', 'T', self.Tout_r, 'Q', 0, self.Ref
) + self.xout_2phase * (
PropsSI('H', 'T', self.Tout_r, 'Q', 1, self.Ref) -
PropsSI('H', 'T', self.Tout_r, 'Q', 0, self.Ref)
) #PropsSI('H','T',self.Tout_r,'Q',self.xout_2phase,self.Ref)#*1000
self.sout_r = PropsSI(
'S', 'T', self.Tout_r, 'Q', 0, self.Ref
) + self.xout_2phase * (
PropsSI('S', 'T', self.Tout_r, 'Q', 1, self.Ref) -
PropsSI('S', 'T', self.Tout_r, 'Q', 0, self.Ref)
) #PropsSI('S','T',self.Tout_r,'Q',self.xout_2phase,self.Ref)#*1000
#Use the effective subcooling
self.DT_sc = self.DT_sc_2phase
#Calculate the mean outlet air temperature [K]
self.Tout_a = self.Tin_a - self.Q / (self.Fins.cp_da *
self.Fins.mdot_da)
self.hmean_r = self.w_2phase * self.h_r_2phase + self.w_superheat * self.h_r_superheat + self.w_subcool * self.h_r_subcool
self.UA_r = self.hmean_r * self.A_r_wetted
self.UA_a = self.Fins.h_a * self.Fins.A_a * self.Fins.eta_a
def Calculate(self):
#Only validate the first time
if not hasattr(self, 'IsValidated'):
self.Fins.Validate()
reqFields = [('Ref', str, None, None),
('Fins', IsFinsClass, None, None),
('mdot_r', float, 0.00001, 20),
('Tin_r', float, 200, 500),
('psat_r', float, 0.01, 20000000)]
optFields = ['Verbosity']
ValidateFields(self.__dict__, reqFields, optFields)
self.IsValidated = True
# Retrieve some parameters from nested structures
# for code compactness
self.Ltube = self.Fins.Tubes.Ltube #tube length
self.NTubes = self.Fins.Tubes.NTubes #number of tube (per bank)
self.Nbank = self.Fins.Tubes.Nbank #number of banks
self.Tin_a = self.Fins.Air.Tdb #inlet air temperature
self.Pin_a = self.Fins.Air.p #inlet air pressure
self.RHin_a = self.Fins.Air.RH #inlet air relative humidity
"""NEW ADDED"""
self.Td = self.Fins.Tubes.Td #tube outside width (depth)
self.Ht = self.Fins.Tubes.Ht #tube outside height (major diameter)
self.b = self.Fins.Tubes.b #tube spacing
self.tw = self.Fins.Tubes.tw #tube thickness
self.Npass = self.Fins.Tubes.Npass #Number of passes on ref-side (per bank)
self.kw = self.Fins.Fins.k_fin #thermal conductivity of tube wall (assume same material as the fin)
self.Nports = self.Fins.Tubes.Nports #Number of rectangular ports
self.twp = self.Fins.Tubes.twp #Port wall thickness
self.beta = self.Fins.Tubes.beta #channel (port) aspect ratio (=width/height)
## Bubble and dew temperatures (same for fluids without glide)
self.Tbubble = PropsSI('T', 'P', self.psat_r, 'Q', 0.0, self.Ref)
self.Tdew = PropsSI('T', 'P', self.psat_r, 'Q', 1.0, self.Ref)
# Define Number of circuits (=number of tubes per pass)
self.Ncircuits = self.NTubes / self.Npass
# Calculate an effective length of circuit if circuits are
# not all the same length
TotalLength = self.Ltube * self.NTubes * self.Nbank
self.Lcircuit = TotalLength / self.Ncircuits
"""NEW ADDED"""
# Volume of refrigerant = rectangle of tube + circular part at the ends - thickness between ports
self.V_r = ((self.Td - self.Ht) * (self.Ht - 2.0 * self.tw) +
(pi / 4.0) * (self.Ht - 2.0 * self.tw)**2 -
(self.Ht - 2.0 * self.tw) * self.twp *
(self.Nports - 1)) * self.Lcircuit * self.Ncircuits
# Tube wetted area = tube straight length + circular shape at the ends - horizontal port thickness + vertical thickness between ports
self.A_r_wetted = (2.0 * (self.Td - self.Ht) + pi *
(self.Ht - 2.0 * self.tw) - 2.0 * self.twp *
(self.Nports - 1) + 2.0 *
(self.Ht - 2.0 * self.tw) *
(self.Nports - 1)) * self.Lcircuit * self.Ncircuits
# Free-flow area on refrigerant-side = area of rectangle tube + circular parts at end - area thickness between ports
self.A_c = ((self.Td - self.Ht) * (self.Ht - 2.0 * self.tw) +
(pi / 4.0) * (self.Ht - 2.0 * self.tw)**2 - self.twp *
(self.Ht - 2.0 * self.tw) *
(self.Nports - 1)) * self.Ncircuits
# Hydraulic diameter on ref-side
self.Dh = 4 * self.A_c * self.Lcircuit / self.A_r_wetted
# Mass flux ref-side
self.G_r = self.mdot_r / self.A_c
# Total conduction area (exclude port's thickness)
self.Aw = 2 * (self.Td - self.twp *
(self.Nports - 1)) * self.Lcircuit * self.Ncircuits
# Thermal resistance at the wall
self.Rw = self.tw / (self.kw * self.Aw)
#Definitely have a superheated portion
self._Superheat_Forward()
#Maybe have a full two-phase section
#First try to run with a full two-phase section from quality of 1 to quality of 0
self._TwoPhase_Forward()
#If we have already used too much of the HX (max possible sum of w is 1.0)
if self.w_2phase + self.w_superheat > 1:
#There is no subcooled portion, solve for outlet quality
brentq(self._TwoPhase_Forward, 0.0000001, 0.9999999)
#Zero out all the subcooled parameters
self.Q_subcool = 0.0
self.DP_r_subcool = 0.0
self.Charge_subcool = 0.0
self.w_subcool = 0.0
self.h_r_subcool = 0.0
self.existsSubcooled = False
else:
#By definition then we have a subcooled portion, solve for it
self.existsSubcooled = True
self._Subcool_Forward()
#Overall calculations
self.Q = self.Q_superheat + self.Q_2phase + self.Q_subcool
self.DP_r = self.DP_r_superheat + self.DP_r_2phase + self.DP_r_subcool
self.Charge = self.Charge_2phase + self.Charge_subcool + self.Charge_superheat
self.sin_r = PropsSI('S', 'T', self.Tin_r, 'P', self.psat_r, self.Ref)
if self.existsSubcooled == True:
self.hout_r = PropsSI('H', 'T', self.Tout_r, 'P', self.psat_r,
self.Ref)
self.sout_r = PropsSI('S', 'T', self.Tout_r, 'P', self.psat_r,
self.Ref)
else:
self.Tout_r = self.xout_2phase * self.Tdew + (
1 - self.xout_2phase) * self.Tbubble
self.hout_r = PropsSI(
'H', 'T', self.Tbubble, 'Q', 0,
self.Ref) + self.xout_2phase * (
PropsSI('H', 'T', self.Tdew, 'Q', 1, self.Ref) -
PropsSI('H', 'T', self.Tbubble, 'Q', 0, self.Ref))
self.sout_r = PropsSI(
'S', 'T', self.Tbubble, 'Q', 0,
self.Ref) + self.xout_2phase * (
PropsSI('S', 'T', self.Tdew, 'Q', 1, self.Ref) -
PropsSI('S', 'T', self.Tbubble, 'Q', 0, self.Ref))
#Use the effective subcooling
self.DT_sc = self.DT_sc_2phase
#Calculate the mean outlet air temperature [K]
self.Tout_a = self.Tin_a - self.Q / (self.Fins.cp_da *
self.Fins.mdot_da)
self.hmean_r = self.w_2phase * self.h_r_2phase + self.w_superheat * self.h_r_superheat + self.w_subcool * self.h_r_subcool
self.UA_r = self.hmean_r * self.A_r_wetted
self.UA_a = self.Fins.h_a * self.Fins.A_a * self.Fins.eta_a
self.UA_w = 1 / self.Rw
#Upadte air-side pressure drop based on the outlet air temperature
#the air-side pressure drop here include momentum, contraction and expansion effects
#Objective function
def OBJECTIVE(x):
Pair_o = x[0]
W = x[1]
v_da = HAPropsSI('V', 'T', self.Tout_a, 'P', Pair_o, 'W', W)
W_new = HAPropsSI('W', 'T', self.Tout_a, 'P', Pair_o, 'V', v_da)
#outlet air density
rho_o = 1 / v_da * (1 + W_new) #[m^3/kg_ha]
#mean air density
rho_m = pow(0.5 * (1 / self.Fins.rho_i_air + 1 / rho_o), -1)
#air-side pressure drop including momentum, expansion and contraction effects
DeltaP_air = self.Fins.G_air**2 / 2 / self.Fins.rho_i_air * (
(1 - self.Fins.sigma**2 + self.Fins.Kc_tri) + 2 *
(self.Fins.rho_i_air / rho_o - 1) +
self.Fins.f_a * self.Fins.A_a / self.Fins.A_a_c *
(self.Fins.rho_i_air / rho_m) -
(1 - self.Fins.sigma**2 - self.Fins.Ke_tri) *
(self.Fins.rho_i_air / rho_o))
resids = [(self.Pin_a - Pair_o) - DeltaP_air, W - W_new]
return resids
#Initial guesses
P_init = self.Pin_a
w_init = HAPropsSI('W', 'T', self.Tin_a, 'P', self.Pin_a, 'R',
self.RHin_a)
#solve for outlet air pressure and outlet humidity ratio
x = fsolve(OBJECTIVE, [P_init, w_init])
#update the air-side pressure drop
self.dP_a = self.Pin_a - x[0]