def maxSubcritORCBoilTemp(orc_fluid):
P_crit = FluidState.getPcrit(orc_fluid)
# assume min pressure is condensing at 0C
P_min = FluidState.getStateFromTQ(0, 1, orc_fluid).P_Pa
dP = (P_crit - P_min) / 1000
# find pressure with maximum entropy
P = np.arange(P_min, P_crit, dP)
s = FluidState.getStateFromPQ(P, 1, orc_fluid).s_JK
max_s = np.max(s)
row_index = np.argmax(s, axis=0)
max_P = P[row_index]
return FluidState.getStateFromPS(max_P, max_s, orc_fluid).T_C
def solve(self):
results = FluidSystemCO2Output()
results.pp = PowerPlantEnergyOutput()
# Find condensation pressure
T_condensation = self.params.T_ambient_C + self.params.dT_approach
P_condensation = FluidState.getStateFromTQ(T_condensation, 0, self.params.working_fluid).P_Pa + 50e3
dP_pump = 0
dP_downhole_threshold = 1e3
dP_downhole = np.nan
dP_loops = 1
dP_solver = Solver()
while np.isnan(dP_downhole) or np.abs(dP_downhole) >= dP_downhole_threshold:
# Find Injection Conditions
P_pump_inlet = P_condensation
# Only add pump differential if positive. If negative, add as a throttle at the bottom of the injection well
if (dP_pump > 0):
P_pump_outlet = P_pump_inlet + dP_pump
else:
P_pump_outlet = P_pump_inlet
T_pump_inlet = T_condensation
pump_inlet_state = FluidState.getStateFromPT(P_pump_inlet, T_pump_inlet, self.params.working_fluid)
if dP_pump > 0:
h_pump_outletS = FluidState.getStateFromPS(P_pump_outlet, pump_inlet_state.s_JK, self.params.working_fluid).h_Jkg
h_pump_outlet = pump_inlet_state.h_Jkg + (h_pump_outletS - pump_inlet_state.h_Jkg) / self.params.eta_pump_co2
else:
h_pump_outlet = pump_inlet_state.h_Jkg
results.pp.w_pump = -1 * (h_pump_outlet - pump_inlet_state.h_Jkg)
surface_injection_state = FluidState.getStateFromPh(P_pump_outlet, h_pump_outlet, self.params.working_fluid)
results.injection_well = self.injection_well.solve(surface_injection_state)
# if dP_pump is negative, this is a throttle after the injection well
if (dP_pump < 0):
results.injection_well_downhole_throttle = FluidState.getStateFromPh(
results.injection_well.state.P_Pa + dP_pump,
results.injection_well.state.h_Jkg,
self.params.working_fluid)
else:
results.injection_well_downhole_throttle = FluidState.getStateFromPh(
results.injection_well.state.P_Pa,
results.injection_well.state.h_Jkg,
self.params.working_fluid)
results.reservoir = self.reservoir.solve(results.injection_well_downhole_throttle)
# find downhole pressure difference (negative means
# overpressure
dP_downhole = self.params.P_reservoir() - results.reservoir.state.P_Pa
dP_pump = dP_solver.addDataAndEstimate(dP_pump, dP_downhole)
if np.isnan(dP_pump):
dP_pump = 0.5 * dP_downhole
if dP_loops > 10:
print('GenGeo::Warning::FluidSystemCO2:dP_loops is large: %s'%dP_loops)
dP_loops += 1
if results.reservoir.state.P_Pa >= self.params.P_reservoir_max():
raise Exception('GenGeo::FluidSystemCO2:ExceedsMaxReservoirPressure - '
'Exceeds Max Reservoir Pressure of %.3f MPa!'%(self.params.P_reservoir_max()/1e6))
results.production_well = self.production_well.solve(results.reservoir.state)
# Subtract surface frictional losses between production wellhead and surface plant
ff = frictionFactor(self.params.well_radius, results.production_well.state.P_Pa, results.production_well.state.h_Jkg,
self.params.m_dot_IP, self.params.working_fluid, self.params.epsilon)
if self.params.has_surface_gathering_system == True:
dP_surfacePipes = ff * self.params.well_spacing / (self.params.well_radius*2)**5 * 8 * self.params.m_dot_IP**2 / results.production_well.state.rho_kgm3 / 3.14159**2
else:
dP_surfacePipes = 0
results.surface_plant_inlet = FluidState.getStateFromPh(
results.production_well.state.P_Pa - dP_surfacePipes,
results.production_well.state.h_Jkg,
self.params.working_fluid)
# Calculate Turbine Power
h_turbine_outS = FluidState.getStateFromPS(P_condensation, results.surface_plant_inlet.s_JK, self.params.working_fluid).h_Jkg
h_turbine_out = results.surface_plant_inlet.h_Jkg - self.params.eta_turbine_co2 * (results.surface_plant_inlet.h_Jkg - h_turbine_outS)
results.pp.w_turbine = results.surface_plant_inlet.h_Jkg - h_turbine_out
if results.pp.w_turbine < 0:
raise Exception('GenGeo::FluidSystemCO2:TurbinePowerNegative - Turbine Power is Negative')
# heat rejection
h_satVapor = FluidState.getStateFromPQ(P_condensation, 1, self.params.working_fluid).h_Jkg
h_condensed = FluidState.getStateFromPQ(P_condensation, 0, self.params.working_fluid).h_Jkg
if h_turbine_out > h_satVapor:
# desuperheating needed
results.pp.q_cooler = h_satVapor - h_turbine_out
results.pp.q_condenser = h_condensed - h_satVapor
T_turbine_out = FluidState.getStateFromPh(P_condensation, h_turbine_out, self.params.working_fluid).T_C
dT_range = T_turbine_out - T_condensation
else:
# no desuperheating
results.pp.q_cooler = 0
results.pp.q_condenser = h_condensed - h_turbine_out
dT_range = 0
parasiticPowerFraction = CoolingCondensingTower.parasiticPowerFraction(self.params.T_ambient_C, self.params.dT_approach, dT_range, self.params.cooling_mode)
results.pp.w_cooler = results.pp.q_cooler * parasiticPowerFraction('cooling')
results.pp.w_condenser = results.pp.q_condenser * parasiticPowerFraction('condensing')
results.pp.w_net = results.pp.w_turbine + results.pp.w_pump + results.pp.w_cooler + results.pp.w_condenser
results.pp.dP_surface = results.surface_plant_inlet.P_Pa - P_condensation
results.pp.dP_pump = dP_pump
results.pp.state_out = surface_injection_state
return results
def heatExchanger(T_1_in, P_1, m_dot_1, fluid_1, T_2_in, P_2, m_dot_2, fluid_2,
dT_pinch):
results = HeatExchangerResults()
# Only tested where Temp1 < Temp2
if T_1_in > T_2_in:
# throw(MException('HeatExchanger:BadTemps','Temp 1 is greater than Temp 2!'));
# No heat exchanged
results.T_1_out = T_1_in
results.T_2_out = T_2_in
return results
if m_dot_1 <= 0 or m_dot_2 <= 0:
raise Exception(
'GenGeo::HeatExchanger:NegativeMassFlow - Negative Massflow in Heat Exchanger'
)
increments = 20
direction = np.sign(T_1_in - T_2_in)
# Check the phase on incoming fluid
P_crit_1 = FluidState.getPcrit(fluid_1)
if P_1 < P_crit_1:
T_sat_1 = FluidState.getStateFromPQ(P_1, 1, fluid_1).T_C
if T_sat_1 == T_1_in or T_sat_1 == T_2_in:
raise Exception(
'GenGeo::HeatExchanger:TwoPhaseFluid - Fluid 1 enters or leaves two-phase!'
)
P_crit_2 = FluidState.getPcrit(fluid_2)
if P_2 < P_crit_2:
T_sat_2 = FluidState.getStateFromPQ(P_2, 1, fluid_2).T_C
if T_sat_2 == T_1_in or T_sat_2 == T_2_in:
raise Exception(
'GenGeo::HeatExchanger:TwoPhaseFluid - Fluid 2 enters or leaves two-phase!'
)
h_1_in = FluidState.getStateFromPT(P_1, T_1_in, fluid_1).h_Jkg
T_1_max = T_2_in
h_1_max = FluidState.getStateFromPT(P_1, T_1_max, fluid_1).h_Jkg
T_1_max_practical = T_2_in + direction * dT_pinch
h_1_max_practical = FluidState.getStateFromPT(P_1, T_1_max_practical,
fluid_1).h_Jkg
h_2_in = FluidState.getStateFromPT(P_2, T_2_in, fluid_2).h_Jkg
T_2_max = T_1_in
h_2_max = FluidState.getStateFromPT(P_2, T_2_max, fluid_2).h_Jkg
T_2_max_practical = T_1_in - direction * dT_pinch
h_2_max_practical = FluidState.getStateFromPT(P_2, T_2_max_practical,
fluid_2).h_Jkg
Q_1_max = abs(m_dot_1 * (h_1_in - h_1_max))
Q_2_max = abs(m_dot_2 * (h_2_in - h_2_max))
Q_1_max_practical = abs(m_dot_1 * (h_1_in - h_1_max_practical))
Q_2_max_practical = abs(m_dot_2 * (h_2_in - h_2_max_practical))
if abs(Q_1_max) < abs(Q_2_max):
# limitingFluid = 1;
Q_max = Q_1_max
Q_max_practical = Q_1_max_practical
else:
# limtingFluid = 2;
Q_max = Q_2_max
Q_max_practical = Q_2_max_practical
results.Q_exchanged = Q_max_practical
ddT_pinch = 1
length = increments + 1
results.Q = np.zeros(length)
h_1 = np.zeros(length)
results.T_1 = np.zeros(length)
h_2 = np.zeros(length)
results.T_2 = np.zeros(length)
dT = np.zeros(length)
UA = np.zeros(length)
while ddT_pinch > 0.1:
dQ = results.Q_exchanged / increments
results.Q[0] = 0.
h_1[0] = h_1_in
results.T_1[0] = T_1_in
h_2[0] = (Q_2_max - results.Q_exchanged) / m_dot_2 + h_2_max
results.T_2[0] = FluidState.getStateFromPh(P_2, h_2[0], fluid_2).T_C
dT[0] = direction * (results.T_1[0] - results.T_2[0])
UA[0] = dQ / dT[0]
for i in range(1, increments + 1):
results.Q[i] = results.Q[i - 1] + dQ
h_1[i] = h_1[i - 1] + dQ / m_dot_1
h_2[i] = h_2[i - 1] + dQ / m_dot_2
results.T_1[i] = FluidState.getStateFromPh(P_1, h_1[i],
fluid_1).T_C
results.T_2[i] = FluidState.getStateFromPh(P_2, h_2[i],
fluid_2).T_C
dT[i] = direction * (results.T_1[i] - results.T_2[i])
UA[i] = dQ / dT[i]
min_dT = min(dT)
ddT_pinch = dT_pinch - min_dT
# Adjust Q_exchanged
# Use proportional error approach
change = ddT_pinch / (T_2_in - T_1_in)
results.Q_exchanged = (1 - change) * results.Q_exchanged
results.dT_LMTD = results.Q_exchanged / sum(UA)
effectiveness = results.Q_exchanged / Q_max
results.T_1_out = results.T_1[-1]
results.T_2_out = results.T_2[0]
# Check the phase on leaving fluid
if P_1 < P_crit_1:
T_sat_1 = FluidState.getStateFromPQ(P_1, 1, fluid_1).T_C
if T_sat_1 > T_1_in and T_sat_1 < results.T_1_out:
print('Caution: Fluid 1 is phase changing in heat exchanger')
if T_sat_1 == results.T_1_out:
raise Exception(
'GenGeo::HeatExchanger:TwoPhaseFluid - Fluid 1 leaves two-phase!'
)
if P_2 < P_crit_2:
T_sat_2 = FluidState.getStateFromPQ(P_2, 1, fluid_2).T_C
if T_sat_2 > T_2_in and T_sat_2 < results.T_2_out:
print('Caution: Fluid 2 is phase changing in heat exchanger')
if T_sat_2 == results.T_2_out:
raise Exception(
'GenGeo::HeatExchanger:TwoPhaseFluid - Fluid 2 leaves two-phase!'
)
return results
