from __future__ import division, print_function,absolute_import
from math import pi
from matplotlib import docstring
import CoolProp as CP
from .Correlations import f_h_1phase_Tube
from .FinCorrelations import WavyLouveredFins,HerringboneFins, PlainFins, FinInputs
from .DryWetSegment import DWSVals, DryWetSegment
[docs]class CoolingCoilClass():
"""
The module that implements a cooling coil. See documentation for further information
"""
def __init__(self,**kwargs):
"""Load the parameters passed in using the dictionary"""
self.__dict__.update(kwargs)
[docs] def Update(self,**kwargs):
"""Update the parameters passed in using the dictionary"""
self.__dict__.update(kwargs)
[docs] def OutputList(self):
return [
('Volumetric flow rate','m^3/s',self.Fins.Air.Vdot_ha),
('Inlet Dry bulb temp','K',self.Tin_a),
('Inlet Air pressure','Pa',self.Fins.Air.p),
('Inlet Air Relative Humidity','-',self.Fins.Air.RH),
('Tubes per bank','-',self.Fins.Tubes.NTubes_per_bank),
('Number of banks','-',self.Fins.Tubes.Nbank),
('Number circuits','-',self.Fins.Tubes.Ncircuits),
('Length of tube','m',self.Fins.Tubes.Ltube),
('Tube OD','m',self.Fins.Tubes.OD),
('Tube ID','m',self.Fins.Tubes.ID),
('Tube Long. Pitch','m',self.Fins.Tubes.Pl),
('Tube Transverse Pitch','m',self.Fins.Tubes.Pt),
('Fins per inch','1/in',self.Fins.Fins.FPI),
('Fin waviness pd','m',self.Fins.Fins.Pd),
('Fin waviness xf','m',self.Fins.Fins.xf),
('Fin thickness','m',self.Fins.Fins.t),
('Fin Conductivity','W/m-K',self.Fins.Fins.k_fin),
('Fins Type','-',self.FinsType),
('Q Total','W',self.Q),
('Mean HTC glycol','W/m^2-K',self.h_g),
('Reynolds # glycol','-',self.Re_g),
('Pressure drop glycol','Pa',self.DP_g),
('Inlet glycol temp','K',self.Tin_g),
('Outlet glyol temp','K',self.Tout_g),
('Outlet air temp','K',self.Tout_a),
('Mean Air HTC','W/m^2-K',self.Fins.h_a),
('Surface Effectiveness','-',self.Fins.eta_a),
('Air-side area (fin+tubes)','m^2',self.Fins.A_a),
('Mass Flow rate Air','kg/s',self.Fins.mdot_da),
('Pressure Drop Air-side','Pa',self.Fins.dP_a),
('Wetted area fraction','-',self.f_dry),
('Sensible Heat Ratio','-',self.SHR)]
[docs] def Initialize(self):
#AbstractState
if hasattr(self,'Backend_g'): #check if backend is given
AS_g = CP.AbstractState(self.Backend_g, self.Ref_g)
if hasattr(self,'MassFrac_g'):
AS_g.set_mass_fractions([self.MassFrac_g])
else: #otherwise, use the defualt backend
AS_g = CP.AbstractState('HEOS', self.Ref_g)
self.AS_g = AS_g
#Update
self.Update()
# 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
self.pin_a=self.Fins.Air.p
self.RHin_a=self.Fins.Air.RH
# 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 glycol side
self.A_g_wetted=self.Ncircuits*pi*self.ID*self.Lcircuit
# Evaluate the air-side heat transfer and pressure drop
if self.FinsType == 'WavyLouveredFins':
WavyLouveredFins(self.Fins)
elif self.FinsType == 'HerringboneFins':
HerringboneFins(self.Fins)
elif self.FinsType == 'PlainFins':
PlainFins(self.Fins)
[docs] def Calculate(self):
"""
This function is now simply a wrapper around the DryWetSegment()
function in order to decrease the amount of code replication
"""
#Initialize
self.Initialize()
AS_g = self.AS_g
DWS=DWSVals() #DryWetSegment structure
# Store temporary values to be passed to DryWetSegment
DWS.A_a=self.Fins.A_a
DWS.cp_da=self.Fins.cp_da
DWS.eta_a=self.Fins.eta_a
DWS.h_a=self.Fins.h_a #Heat transfer coefficient
DWS.mdot_da=self.Fins.mdot_da
DWS.pin_a=self.Fins.Air.p
DWS.Tin_a=self.Tin_a
DWS.RHin_a=self.Fins.Air.RH
DWS.Fins=self.Fins
DWS.FinsType=self.FinsType #Added to pass FinsType to DryWetSegment
DWS.Tin_r=self.Tin_g
DWS.A_r=self.A_g_wetted
AS_g.update(CP.PT_INPUTS, self.pin_g, (self.Tin_g+DWS.Tin_a)/2.0)
DWS.cp_r=AS_g.cpmass() #[J/kg-K]
DWS.pin_r=self.pin_g
DWS.mdot_r=self.mdot_g
DWS.IsTwoPhase=False
#Use a guess value of 6K superheat to calculate the properties
self.f_g, self.h_g, self.Re_g=f_h_1phase_Tube(self.mdot_g / self.Ncircuits, self.ID,
(self.Tin_g+DWS.Tin_a)/2.0, self.pin_g, self.AS_g, "Single");
# Average Refrigerant heat transfer coefficient
DWS.h_r=self.h_g
#Run DryWetSegment
DryWetSegment(DWS)
#Average mass flux of glycol in circuit
self.G_g = self.mdot_g/(self.Ncircuits*pi*self.ID**2/4.0) #[kg/m^2-s]
#Pressure drop calculations for glycol (water)
Dh_g=self.ID
AS_g.update(CP.PT_INPUTS, self.pin_g, self.Tin_g)
v_g=1/AS_g.rhomass() #[m^3/kg]
#Pressure gradient using Darcy friction factor
dp_dz_g=-self.f_g*v_g*self.G_g**2/(2*Dh_g)
DP_g=dp_dz_g*self.Lcircuit
self.f_dry=DWS.f_dry
self.DP_g=DP_g
self.Q=DWS.Q
self.Tout_g=DWS.Tout_r
self.Tout_a=DWS.Tout_a
self.hout_a=DWS.hout_a
self.hin_a=DWS.hin_a
self.SHR=self.Fins.cp_da*(DWS.Tout_a-DWS.Tin_a)/(DWS.hout_a-DWS.hin_a)
self.Capacity=DWS.Q-self.Fins.Air.FanPower
def TestCase():
CC=CoolingCoilClass()
FinsTubes=FinInputs()
FinsTubes.Tubes.NTubes_per_bank=32
FinsTubes.Tubes.Nbank=3
FinsTubes.Tubes.Ncircuits=5
FinsTubes.Tubes.Ltube=0.452
FinsTubes.Tubes.OD=0.009525
FinsTubes.Tubes.ID=0.0089154
FinsTubes.Tubes.Pl=0.0254
FinsTubes.Tubes.Pt=0.0219964
FinsTubes.Fins.FPI=14.5
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
FinsTubes.Air.RH=0.51
FinsTubes.Air.RHmean=0.51
FinsTubes.Air.FanPower=438
CC.Fins = FinsTubes
CC.FinsType = 'WavyLouveredFins' #Choose fin Type: 'WavyLouveredFins' or 'HerringboneFins'or 'PlainFins'
CC.Ref_g = 'Water'
CC.Backend_g = 'TTSE&HEOS' #choose between: 'HEOS','TTSE&HEOS','BICUBIC&HEOS','REFPROP','SRK','PR'
CC.mdot_g = 0.15
CC.Tin_g = 278
CC.pin_g = 300000
CC.Verbosity = 3
CC.Calculate()
print(CC.OutputList())
if __name__=='__main__':
TestCase()