def humidity_ratio(t, t_d, p):
# CoolProp
try:
mmr = hap.HAPropsSI('W', 'T', t, 'D', t_d, 'P', p)
except:
mmr = 0.9415
return mmr
def compute_hp_param_estimation(params, m_s, m_l, T_s, T_l, q_load, q_source,
humidity, hp_specification):
refrigerant = hp_specification[2]
T_min_ref = CP.PropsSI('TMIN', refrigerant)
T_max_ref = CP.PropsSI('TCRIT', refrigerant)
p_min_ref = CP.PropsSI('PMIN', refrigerant)
p_max_ref = CP.PropsSI('PCRIT', refrigerant)
source_composition = hp_specification[3]
load_composition = hp_specification[4]
# constants
cp_l = CP.PropsSI('CP0MASS', 'T', T_l, 'P', hp_specification[6],
load_composition)
if hp_specification[0] == 'a-a' or hp_specification[0] == 'a-w':
# humid air properties
cp_s = HA.HAPropsSI('cp_ha', 'T', T_s, 'P', hp_specification[5], 'R',
humidity)
epsilon_s = thermal_eff(params[1], m_s, cp_s)
else:
cp_s = CP.PropsSI('C', 'T', T_s, 'P', hp_specification[5],
source_composition)
epsilon_s = thermal_eff(params[1], m_s, cp_s)
epsilon_l = thermal_eff(params[0], m_l, cp_l)
[m_ref, q_source, q_heating,
comp_p] = heat_pump_cycle(params, T_s, T_l, q_load, q_source, m_s, m_l,
hp_specification, [cp_l, cp_s],
[epsilon_l, epsilon_s],
[T_min_ref, T_max_ref, p_min_ref, p_max_ref])
return [q_heating, comp_p, q_source]
def humidity_ratio(t, t_d, p=14.696):
p_pa = p * 6894.76
t_k = (t - 32) * 5 / 9 + 273.15
td_k = (t_d - 32) * 5 / 9 + 273.15
# CoolProp
mmr = hap.HAPropsSI('W', 'T', t_k, 'D', td_k, 'P', p_pa)
return mmr
def relative_humidity(t, t_d, p=14.696):
p_pa = p * 6894.76
t_k = (t - 32) * 5 / 9 + 273.15
td_k = (t_d - 32) * 5 / 9 + 273.15
# CoolProp
rh = hap.HAPropsSI('R', 'T', t_k, 'D', td_k, 'P', p_pa)
return rh
def dew_point(mmr=1e-3, p=14.696):
# Vapor pressure
p_w = vapor_pressure(mmr, p)
# # ASHRAE method
# t_d = 90.12 + 26.412 * np.log(p_w) + 0.8927 * np.log(p_w)**2
# CoolProp method
t_d = hap.HAPropsSI('D', 'W', mmr, 'P', p * 6894.76, 'T', 300)
t_d = (t_d - 273.15) * 1.8 + 32
return t_d
def relative_humidity2(t, t_d, p):
# CoolProp
try:
rh = hap.HAPropsSI('R', 'T', t, 'D', t_d, 'P', p)
except:
if t < t_d: # HAPropsSI doesn't work with supersaturated air; set to 1.0
rh = 1.0
elif t <= 0.0 or t_d <= 0.0: # low humidity; return 0.0
rh = 0.0
else: # unknown error; return error value
rh = -1.0
return rh
def dew_point(mmr, p_psi):
# Vapor pressure
p_w_psi = vapor_pressure(mmr, p_psi)
# Convert to SI units
p_w = p_w_psi / (KPA2PSI / 1000)
p = p_psi / (KPA2PSI / 1000)
# # ASHRAE method
# t_d = 90.12 + 26.412 * np.log(p_w) + 0.8927 * np.log(p_w)**2
# CoolProp method
try:
t_d = hap.HAPropsSI('D', 'W', mmr, 'P', p, 'T', 300)
except:
t_d = 0.0
return (t_d - 273.15) * 9 / 5 + 32 # converted to degreesF
def relative_humidity1(t_f, mmr, p_psi):
# Convert to SI units
t = (t_f - 32) * 5 / 9 + 273.15 # Kelvin
p = p_psi / (KPA2PSI / 1000) # Pascals
# Calculate dew point (K)
t_d = (dew_point(mmr, p_psi) - 32) * 5 / 9 + 273.15
# CoolProp
try:
rh = hap.HAPropsSI('R', 'T', t, 'D', t_d, 'P', p)
except:
if t < t_d: # HAPropsSI doesn't work with supersaturated air; set to 1.0
rh = 1.0
elif t <= 0.0 or t_d <= 0.0: # low humidity; return 0.0
rh = 0.0
else: # unknown error; return error value
rh = -1.0
return rh
def compute_hp_performance(params, T_s, T_l, q_load, m_s, m_l, humidity,
hp_specification):
# constants
iter = 0
maxiter = 1000
tol = 5 * 10**(-2)
q_load_calc = 0
refrigerant = hp_specification[2]
source_composition = hp_specification[3]
load_composition = hp_specification[4]
T_min_ref = CP.PropsSI('TMIN', refrigerant)
T_max_ref = CP.PropsSI('TCRIT', refrigerant)
p_min_ref = CP.PropsSI('PMIN', refrigerant)
p_max_ref = CP.PropsSI('PCRIT', refrigerant)
cp_l = CP.PropsSI('CP0MASS', 'T', T_l, 'P', hp_specification[6],
load_composition)
epsilon_l = thermal_eff(params[0], m_l, cp_l)
if hp_specification[0] == 'a-a' or hp_specification[0] == 'a-w':
# humid air properties
cp_s = HA.HAPropsSI('cp_ha', 'T', T_s, 'P', hp_specification[5], 'R',
humidity)
epsilon_s = thermal_eff(params[1], m_s, cp_s)
else:
cp_s = CP.PropsSI('C', 'T', T_s, 'P', hp_specification[5],
source_composition)
epsilon_s = thermal_eff(params[1], m_s, cp_s)
# initial guess for q_source
q_source = q_load * 0.8
while abs((q_load - q_load_calc) / q_load) > tol and iter < maxiter:
[m_ref, q_source, q_load_calc, comp_p
] = heat_pump_cycle(params, T_s, T_l, q_load, q_source, m_s, m_l,
hp_specification, [cp_l, cp_s],
[epsilon_l, epsilon_s],
[T_min_ref, T_max_ref, p_min_ref, p_max_ref])
iter = iter + 1
return [m_ref, q_source, comp_p, q_load_calc, iter]
# 3 - source composition/ relative humidity , 4 - load composition
hp_specification = hp.loc[0, "HP-Type":"pressure load"].to_numpy()
# convert sample values
samples.T_s = samples.T_s + 273.15
samples.T_l = samples.T_l + 273.15
samples.q_load = samples.q_load * 10**3
samples.q_source = samples.q_source * 10**3
samples.w_el = samples.w_el * 10**3
# convert source volume flow rate to mass flow rate
if hp_array[10] == 'l/s':
if hp_specification[0] == 'a-a' or hp_specification[0] == 'a-w':
for k, row_samples in samples.iterrows():
rho = 1 / HA.HAPropsSI('Vha', 'T', samples.T_s[k], 'P',
hp_specification[5], 'R',
samples.comment[k])
m_s = samples.m_s[k] * rho * 10**(-3)
samples.at[k, 'm_s'] = m_s
hp.at[0, 'flow type source'] = 'kg/s'
else:
for k, row_samples in samples.iterrows():
rho = CP.PropsSI('D', 'P', hp_specification[5], 'T',
samples.T_s[k], hp_specification[3])
m_s = samples.m_s[k] * rho * 10**(-3)
samples.at[k, 'm_s'] = m_s
hp.at[0, 'flow type source'] = 'kg/s'
elif hp_array[10] == 'm^3/h':
if hp_specification[0] == 'a-a' or hp_specification[0] == 'a-w':
for k, row_samples in samples.iterrows():
rho = 1 / HA.HAPropsSI('Vha', 'T', samples.T_s[k], 'P',
def parallel_evaporation(
temperature_interface = 300,
temperature_far_in = 290,
relhum_far_in = 0.2,
dryair_mass_flow_in = 0.1,
water_flow_in = 0.07,
a_cell = 2.,
pressure = 1e5,
cells = 20,
supersaturated_method=None):
"""For supersaturated method, consider 'hack'."""
nodal_temperature = []
nodal_relhum = []
nodal_humrat = []
nodal_water_flow = []
nodal_water_temperature = []
nodal_interface_humrat = []
relhum_interface = 1
nodal_temperature.append(temperature_far_in)
nodal_relhum.append(relhum_far_in)
humrat_far_in = HAP.HAPropsSI('HumRat','P',pressure,'T',temperature_far_in,'RH',relhum_far_in)
nodal_humrat.append(humrat_far_in)
nodal_water_flow.append(water_flow_in)
nodal_water_temperature.append(temperature_interface)
nodal_interface_humrat.append(HAP.HAPropsSI(
'HumRat','P',pressure,'T',temperature_interface,'RH',relhum_interface))
for i in range(cells):
temperature_far = temperature_far_in
relhum_far = relhum_far_in
# Convert to dimensions we wish to average
enthalpy_interface = HAP.HAPropsSI('Hha','P',pressure,'T',temperature_interface,'RH',relhum_interface)
humrat_interface = HAP.HAPropsSI('HumRat','P',pressure,'T',temperature_interface,'RH',relhum_interface)
mole_fraction_interface = HAP.HAPropsSI('Y','P',pressure,'T',temperature_interface,'RH',relhum_interface)
mixture_density_interface = 1 / HAP.HAPropsSI('Vha','P',pressure,'T',temperature_interface,'RH',relhum_interface)
vapor_density_interface = mole_fraction_interface * mixture_density_interface
enthalpy_far = HAP.HAPropsSI('Hha','P',pressure,'T',temperature_far,'RH',relhum_far)
humrat_far = HAP.HAPropsSI('HumRat','P',pressure,'T',temperature_far,'RH',relhum_far)
mole_fraction_far = HAP.HAPropsSI('Y','P',pressure,'T',temperature_far,'RH',relhum_far)
mixture_density_far = 1 / HAP.HAPropsSI('Vha','P',pressure,'T',temperature_far,'RH',relhum_far)
vapor_density_far = mole_fraction_far * mixture_density_far
enthalpy_vapor_interface = CP.PropsSI('H','T',temperature_interface,'Q',1,'water') \
- h_ref_water
# Now determine the film state and transport properties
enthalpy_film = 0.5 * (enthalpy_interface + enthalpy_far)
humrat_film = 0.5 * (humrat_interface + humrat_far)
temperature_film = HAP.HAPropsSI('T','P',pressure,'Hha',enthalpy_film,'HumRat',humrat_film)
relhum_film = HAP.HAPropsSI('RH','P',pressure,'Hha',enthalpy_film,'HumRat',humrat_film)
volume = HAP.HAPropsSI('Vha','P',pressure,'Hha',enthalpy_film,'HumRat',humrat_film)
density = 1 / volume
c_p = HAP.HAPropsSI('Cha','P',pressure,'Hha',enthalpy_film,'HumRat',humrat_film)
k = HAP.HAPropsSI('K','P',pressure,'Hha',enthalpy_film,'HumRat',humrat_film)
mu = HAP.HAPropsSI('mu','P',pressure,'Hha',enthalpy_film,'HumRat',humrat_film)
nu = mu * volume
prandtl = c_p * mu / k
#print(prandtl)
#print(vapor_density_far, vapor_density_interface, mixture_density_far)
length_scale = 0.01
velocity = 1
nusselt = 1
h_heat = nusselt * k / length_scale
stanton_heat = h_heat / (density * velocity * c_p)
#print(stanton_heat)
# Mass diffusivity [m2/s]
# TODO: add a lookup-table with temperature
diffusivity_mass = 2.5e-5
schmidt = nu / diffusivity_mass
lewis = schmidt / prandtl
#print(lewis)
stanton_ratio = pow(lewis, 2/3)
#print(stanton_ratio)
stanton_mass = stanton_heat / stanton_ratio
h_mass = stanton_mass * velocity
#print(h_mass)
flow_per_area_mass = h_mass * (vapor_density_interface - vapor_density_far)
flow_per_area_heat = h_heat * (temperature_interface - temperature_far)
flow_per_area_mass, flow_per_area_heat
mass_flow_cell = a_cell * flow_per_area_mass
heat_flow_cell = a_cell * flow_per_area_heat
# If the state is near saturation and getting closer,
# then we need to dial down the water vapor influx.
# Water vapor outflux is okay, as it tends to drive away from saturation.
if supersaturated_method is 'hack':
if relhum_film > 1 and mass_flow_cell > 0:
mass_flow_cell = 0
water_flow_out = water_flow_in - mass_flow_cell
humrat_in = humrat_far
humair_mass_flow_in = dryair_mass_flow_in * (1+humrat_in)
humair_mass_flow_out = humair_mass_flow_in + mass_flow_cell
humrat_out = humair_mass_flow_out / dryair_mass_flow_in - 1
enthalpy_ave_in = enthalpy_far
total_enthalpy_in = humair_mass_flow_in * enthalpy_ave_in
total_enthalpy_out = total_enthalpy_in + heat_flow_cell \
+ mass_flow_cell * enthalpy_vapor_interface
enthalpy_ave_out = total_enthalpy_out / humair_mass_flow_out
water_total_enthalpy_in = water_flow_in * CP.PropsSI('H','T',temperature_interface,'Q',0,'water')
water_total_enthalpy_out = water_total_enthalpy_in - heat_flow_cell \
- mass_flow_cell * enthalpy_vapor_interface
water_enthalpy_out = water_total_enthalpy_out / water_flow_out
water_temperature_out = CP.PropsSI('T','H',water_enthalpy_out,'P',pressure,'water')
#print(water_temperature_out)
interface_humrat_out = HAP.HAPropsSI('HumRat','P',pressure,'T',water_temperature_out,'RH',relhum_interface)
t_out = HAP.HAPropsSI('T','P',pressure,'Hha',enthalpy_ave_out,'HumRat',humrat_out)
rh_out = HAP.HAPropsSI('RH','P',pressure,'Hha',enthalpy_ave_out,'HumRat',humrat_out)
temperature_far_in = t_out
relhum_far_in = rh_out
water_flow_in = water_flow_out
temperature_interface = water_temperature_out
nodal_temperature.append(t_out)
nodal_relhum.append(rh_out)
nodal_humrat.append(humrat_out)
nodal_water_flow.append(water_flow_out)
nodal_water_temperature.append(water_temperature_out)
nodal_interface_humrat.append(interface_humrat_out)
result = pandas.DataFrame.from_dict(dict(
T_air=nodal_temperature,
RelHum=nodal_relhum,
HumRat_air=nodal_humrat,
WaterFlow=nodal_water_flow,
T_water=nodal_water_temperature,
HumRat_interface=nodal_interface_humrat
))
return result