/
sco2_htrbypass_cycle.cpp
2163 lines (1768 loc) · 91.2 KB
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sco2_htrbypass_cycle.cpp
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/*
BSD 3-Clause License
Copyright (c) Alliance for Sustainable Energy, LLC. See also https://github.com/NREL/ssc/blob/develop/LICENSE
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "sco2_htrbypass_cycle.h"
#include "sco2_cycle_components.h"
#include "CO2_properties.h"
#include "fmin.h"
// ********************************************************************************** C_sco2_htrbp_core CORE MODEL
void C_sco2_htrbp_core::initialize_solve()
{
m_outputs.Init();
}
int C_sco2_htrbp_core::solve()
{
initialize_solve();
m_outputs.m_error_code = -1;
// Apply scaling to the turbomachinery here
{
m_outputs.m_mc_ms.m_r_W_dot_scale = m_inputs.m_W_dot_net_design / 10.E3; //[-]
m_outputs.m_rc_ms.m_r_W_dot_scale = m_outputs.m_mc_ms.m_r_W_dot_scale; //[-]
m_outputs.m_t.m_r_W_dot_scale = m_outputs.m_mc_ms.m_r_W_dot_scale; //[-]
}
// Initialize Recuperators
{
// LTR
m_outputs.mc_LT_recup.initialize(m_inputs.m_LTR_N_sub_hxrs, m_inputs.m_LTR_od_UA_target_type);
// HTR
m_outputs.mc_HT_recup.initialize(m_inputs.m_HTR_N_sub_hxrs, m_inputs.m_HTR_od_UA_target_type);
}
// Initialize a few variables
{
m_outputs.m_temp[C_sco2_cycle_core::MC_IN] = m_inputs.m_T_mc_in; //[K]
m_outputs.m_pres[C_sco2_cycle_core::MC_IN] = m_inputs.m_P_mc_in;
m_outputs.m_pres[C_sco2_cycle_core::MC_OUT] = m_inputs.m_P_mc_out;
m_outputs.m_temp[C_sco2_cycle_core::TURB_IN] = m_inputs.m_T_t_in; //[K]
}
// Apply pressure drops to heat exchangers, fully defining the pressures at all states
{
if (m_inputs.m_DP_LTR[0] < 0.0)
m_outputs.m_pres[C_sco2_cycle_core::LTR_HP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::MC_OUT] - m_outputs.m_pres[C_sco2_cycle_core::MC_OUT] * std::abs(m_inputs.m_DP_LTR[0]); // relative pressure drop specified for LT recuperator (cold stream)
else
m_outputs.m_pres[C_sco2_cycle_core::LTR_HP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::MC_OUT] - m_inputs.m_DP_LTR[0]; // absolute pressure drop specified for LT recuperator (cold stream)
if ((m_inputs.m_LTR_target_code == NS_HX_counterflow_eqs::OPTIMIZE_UA && m_inputs.m_LTR_UA < 1.0E-12)
|| (m_inputs.m_LTR_target_code == NS_HX_counterflow_eqs::TARGET_UA && m_inputs.m_LTR_UA < 1.0E-12)
|| (m_inputs.m_LTR_target_code == NS_HX_counterflow_eqs::TARGET_MIN_DT && m_inputs.m_LTR_min_dT < 1.0E-12)
|| (m_inputs.m_LTR_target_code == NS_HX_counterflow_eqs::TARGET_EFFECTIVENESS && m_inputs.m_LTR_eff_target < 1.0E-12))
m_outputs.m_pres[C_sco2_cycle_core::LTR_HP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::MC_OUT]; // If there is no LT recuperator, there is no pressure drop
m_outputs.m_pres[C_sco2_cycle_core::MIXER_OUT] = m_outputs.m_pres[C_sco2_cycle_core::LTR_HP_OUT]; // Assume no pressure drop in mixing valve
m_outputs.m_pres[C_sco2_cycle_core::RC_OUT] = m_outputs.m_pres[C_sco2_cycle_core::LTR_HP_OUT]; // Assume no pressure drop in mixing valve
if (m_inputs.m_DP_HTR[0] < 0.0)
m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::MIXER_OUT]
- m_outputs.m_pres[C_sco2_cycle_core::MIXER_OUT] * std::abs(m_inputs.m_DP_HTR[0]); // relative pressure drop specified for HT recuperator (cold stream)
else
m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::MIXER_OUT] - m_inputs.m_DP_HTR[0]; // absolute pressure drop specified for HT recuperator (cold stream)
if ((m_inputs.m_HTR_target_code == NS_HX_counterflow_eqs::OPTIMIZE_UA && m_inputs.m_HTR_UA < 1.0E-12)
|| (m_inputs.m_HTR_target_code == NS_HX_counterflow_eqs::TARGET_UA && m_inputs.m_HTR_UA < 1.0E-12)
|| (m_inputs.m_HTR_target_code == NS_HX_counterflow_eqs::TARGET_MIN_DT && m_inputs.m_HTR_min_dT < 1.0E-12)
|| (m_inputs.m_HTR_target_code == NS_HX_counterflow_eqs::TARGET_EFFECTIVENESS && m_inputs.m_HTR_eff_target < 1.0E-12))
m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::MIXER_OUT]; // If there is no HT recuperator, there is no pressure drop
if (m_inputs.m_DP_PHX[0] < 0.0)
m_outputs.m_pres[C_sco2_cycle_core::TURB_IN] = m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT] - m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT] * std::abs(m_inputs.m_DP_PHX[0]); // relative pressure drop specified for PHX
else
m_outputs.m_pres[C_sco2_cycle_core::TURB_IN] = m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT] - m_inputs.m_DP_PHX[0]; // absolute pressure drop specified for PHX
if (m_inputs.m_DP_PC_main[1] < 0.0)
m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::MC_IN] / (1.0 - std::abs(m_inputs.m_DP_PC_main[1])); // relative pressure drop specified for precooler: P1=P9-P9*rel_DP => P1=P9*(1-rel_DP)
else
m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::MC_IN] + m_inputs.m_DP_PC_main[1];
if (m_inputs.m_DP_LTR[1] < 0.0)
m_outputs.m_pres[C_sco2_cycle_core::HTR_LP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT] / (1.0 - std::abs(m_inputs.m_DP_LTR[1])); // relative pressure drop specified for LT recuperator (hot stream)
else
m_outputs.m_pres[C_sco2_cycle_core::HTR_LP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT] + m_inputs.m_DP_LTR[1]; // absolute pressure drop specified for LT recuperator (hot stream)
if ((m_inputs.m_LTR_target_code == NS_HX_counterflow_eqs::OPTIMIZE_UA && m_inputs.m_LTR_UA < 1.0E-12)
|| (m_inputs.m_LTR_target_code == NS_HX_counterflow_eqs::TARGET_UA && m_inputs.m_LTR_UA < 1.0E-12)
|| (m_inputs.m_LTR_target_code == NS_HX_counterflow_eqs::TARGET_MIN_DT && m_inputs.m_LTR_min_dT < 1.0E-12)
|| (m_inputs.m_LTR_target_code == NS_HX_counterflow_eqs::TARGET_EFFECTIVENESS && m_inputs.m_LTR_eff_target < 1.0E-12))
m_outputs.m_pres[C_sco2_cycle_core::HTR_LP_OUT] = m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT]; // if there is no LT recuperator, there is no pressure drop
if (m_inputs.m_DP_HTR[1] < 0.0)
m_outputs.m_pres[C_sco2_cycle_core::TURB_OUT] = m_outputs.m_pres[C_sco2_cycle_core::HTR_LP_OUT] / (1.0 - std::abs(m_inputs.m_DP_HTR[1])); // relative pressure drop specified for HT recuperator (hot stream)
else
m_outputs.m_pres[C_sco2_cycle_core::TURB_OUT] = m_outputs.m_pres[C_sco2_cycle_core::HTR_LP_OUT] + m_inputs.m_DP_HTR[1]; // absolute pressure drop specified for HT recuperator (hot stream)
if ((m_inputs.m_HTR_target_code == NS_HX_counterflow_eqs::OPTIMIZE_UA && m_inputs.m_HTR_UA < 1.0E-12)
|| (m_inputs.m_HTR_target_code == NS_HX_counterflow_eqs::TARGET_UA && m_inputs.m_HTR_UA < 1.0E-12)
|| (m_inputs.m_HTR_target_code == NS_HX_counterflow_eqs::TARGET_MIN_DT && m_inputs.m_HTR_min_dT < 1.0E-12)
|| (m_inputs.m_HTR_target_code == NS_HX_counterflow_eqs::TARGET_EFFECTIVENESS && m_inputs.m_HTR_eff_target < 1.0E-12))
m_outputs.m_pres[C_sco2_cycle_core::TURB_OUT] = m_outputs.m_pres[C_sco2_cycle_core::HTR_LP_OUT]; // if there is no HT recuperator, there is no pressure drop
// Added pressures
m_outputs.m_pres[C_sco2_cycle_core::BYPASS_OUT] = m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT];
m_outputs.m_pres[C_sco2_cycle_core::MIXER2_OUT] = m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT];
}
// Determine equivalent isentropic efficiencies for main compressor and turbine, if necessary.
double eta_mc_isen = std::numeric_limits<double>::quiet_NaN();
double eta_t_isen = std::numeric_limits<double>::quiet_NaN();
{
if (m_inputs.m_eta_mc < 0.0)
{
int poly_error_code = 0;
isen_eta_from_poly_eta(m_outputs.m_temp[C_sco2_cycle_core::MC_IN], m_outputs.m_pres[C_sco2_cycle_core::MC_IN], m_outputs.m_pres[C_sco2_cycle_core::MC_OUT], std::abs(m_inputs.m_eta_mc),
true, poly_error_code, eta_mc_isen);
if (poly_error_code != 0)
{
m_outputs.m_error_code = poly_error_code;
return m_outputs.m_error_code;
}
}
else
eta_mc_isen = m_inputs.m_eta_mc;
if (m_inputs.m_eta_t < 0.0)
{
int poly_error_code = 0;
isen_eta_from_poly_eta(m_outputs.m_temp[C_sco2_cycle_core::TURB_IN], m_outputs.m_pres[C_sco2_cycle_core::TURB_IN], m_outputs.m_pres[C_sco2_cycle_core::TURB_OUT], std::abs(m_inputs.m_eta_t),
false, poly_error_code, eta_t_isen);
if (poly_error_code != 0)
{
m_outputs.m_error_code = poly_error_code;
return m_outputs.m_error_code;
}
}
else
eta_t_isen = m_inputs.m_eta_t;
}
// Determine the outlet state and specific work for the main compressor and turbine.
// Main compressor
m_outputs.m_w_mc = std::numeric_limits<double>::quiet_NaN();
{
int comp_error_code = 0;
calculate_turbomachinery_outlet_1(m_outputs.m_temp[C_sco2_cycle_core::MC_IN], m_outputs.m_pres[C_sco2_cycle_core::MC_IN], m_outputs.m_pres[C_sco2_cycle_core::MC_OUT], eta_mc_isen, true,
comp_error_code, m_outputs.m_enth[C_sco2_cycle_core::MC_IN], m_outputs.m_entr[C_sco2_cycle_core::MC_IN], m_outputs.m_dens[C_sco2_cycle_core::MC_IN], m_outputs.m_temp[C_sco2_cycle_core::MC_OUT],
m_outputs.m_enth[C_sco2_cycle_core::MC_OUT], m_outputs.m_entr[C_sco2_cycle_core::MC_OUT], m_outputs.m_dens[C_sco2_cycle_core::MC_OUT], m_outputs.m_w_mc);
if (comp_error_code != 0)
{
m_outputs.m_error_code = comp_error_code;
return m_outputs.m_error_code;
}
}
// Turbine
m_outputs.m_w_t = std::numeric_limits<double>::quiet_NaN();
{
int turbine_error_code = 0;
calculate_turbomachinery_outlet_1(m_outputs.m_temp[C_sco2_cycle_core::TURB_IN], m_outputs.m_pres[C_sco2_cycle_core::TURB_IN], m_outputs.m_pres[C_sco2_cycle_core::TURB_OUT], eta_t_isen, false,
turbine_error_code, m_outputs.m_enth[C_sco2_cycle_core::TURB_IN], m_outputs.m_entr[C_sco2_cycle_core::TURB_IN], m_outputs.m_dens[C_sco2_cycle_core::TURB_IN], m_outputs.m_temp[C_sco2_cycle_core::TURB_OUT],
m_outputs.m_enth[C_sco2_cycle_core::TURB_OUT], m_outputs.m_entr[C_sco2_cycle_core::TURB_OUT], m_outputs.m_dens[C_sco2_cycle_core::TURB_OUT], m_outputs.m_w_t);
if (turbine_error_code != 0)
{
m_outputs.m_error_code = turbine_error_code;
return m_outputs.m_error_code;
}
}
// Check that this cycle can produce power
m_outputs.m_w_rc = std::numeric_limits<double>::quiet_NaN();
{
double eta_rc_isen = std::numeric_limits<double>::quiet_NaN();
if (m_inputs.m_recomp_frac >= 1.E-12)
{
if (m_inputs.m_eta_rc < 0.0) // need to convert polytropic efficiency to isentropic efficiency
{
int rc_error_code = 0;
isen_eta_from_poly_eta(m_outputs.m_temp[C_sco2_cycle_core::MC_OUT], m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT], m_outputs.m_pres[C_sco2_cycle_core::RC_OUT], std::abs(m_inputs.m_eta_rc),
true, rc_error_code, eta_rc_isen);
if (rc_error_code != 0)
{
m_outputs.m_error_code = rc_error_code;
return m_outputs.m_error_code;
}
}
else
eta_rc_isen = m_inputs.m_eta_rc;
int rc_error_code = 0;
calculate_turbomachinery_outlet_1(m_outputs.m_temp[C_sco2_cycle_core::MC_OUT], m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT], m_outputs.m_pres[C_sco2_cycle_core::RC_OUT], eta_rc_isen,
true, rc_error_code, m_outputs.m_w_rc);
if (rc_error_code != 0)
{
m_outputs.m_error_code = rc_error_code;
return m_outputs.m_error_code;
}
}
else
m_outputs.m_w_rc = 0.0;
if (m_outputs.m_w_mc + m_outputs.m_w_rc + m_outputs.m_w_t <= 0.0) // positive net power is impossible; return an error
{
m_outputs.m_error_code = (int)C_sco2_cycle_core::E_cycle_error_msg::E_CANNOT_PRODUCE_POWER;
return m_outputs.m_error_code;
}
}
// Solve the recuperators
{
C_mono_htrbp_core_HTR_des HTR_des_eq(this);
C_monotonic_eq_solver HTR_des_solver(HTR_des_eq);
{
double T_HTR_LP_out_lower = m_outputs.m_temp[C_sco2_cycle_core::MC_OUT]; //[K] Coldest possible temperature
double T_HTR_LP_out_upper = m_outputs.m_temp[C_sco2_cycle_core::TURB_OUT]; //[K] Hottest possible temperature
double T_HTR_LP_out_guess_lower = std::min(T_HTR_LP_out_upper - 2.0, std::max(T_HTR_LP_out_lower + 15.0, 220.0 + 273.15)); //[K] There is nothing special about these guesses...
double T_HTR_LP_out_guess_upper = std::min(T_HTR_LP_out_guess_lower + 20.0, T_HTR_LP_out_upper - 1.0); //[K] There is nothing special about these guesses, either...
HTR_des_solver.settings(m_inputs.m_des_tol * m_outputs.m_temp[C_sco2_cycle_core::MC_IN], 1000, T_HTR_LP_out_lower, T_HTR_LP_out_upper, false);
double T_HTR_LP_out_solved, tol_T_HTR_LP_out_solved;
T_HTR_LP_out_solved = tol_T_HTR_LP_out_solved = std::numeric_limits<double>::quiet_NaN();
int iter_T_HTR_LP_out = -1;
int T_HTR_LP_out_code = HTR_des_solver.solve(T_HTR_LP_out_guess_lower, T_HTR_LP_out_guess_upper, 0,
T_HTR_LP_out_solved, tol_T_HTR_LP_out_solved, iter_T_HTR_LP_out);
if (T_HTR_LP_out_code != C_monotonic_eq_solver::CONVERGED)
{
m_outputs.m_error_code = (int)C_sco2_cycle_core::E_cycle_error_msg::E_HTR_LTR_CONVERGENCE;
return m_outputs.m_error_code;
}
double test = 0;
solve_HTR(T_HTR_LP_out_solved, &test);
}
}
// State 5 can now be fully defined
{
// Check if there is flow through HTR_HP
if (m_outputs.m_m_dot_htr_hp <= 1e-12)
m_outputs.m_enth[C_sco2_cycle_core::HTR_HP_OUT] = m_outputs.m_enth[C_sco2_cycle_core::MIXER_OUT];
else
m_outputs.m_enth[C_sco2_cycle_core::HTR_HP_OUT] = m_outputs.m_enth[C_sco2_cycle_core::MIXER_OUT] + m_outputs.m_Q_dot_HT / m_outputs.m_m_dot_htr_hp; // Energy balance on cold stream of high-temp recuperator
int prop_error_code = CO2_PH(m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT], m_outputs.m_enth[C_sco2_cycle_core::HTR_HP_OUT], &m_co2_props);
if (prop_error_code != 0)
{
m_outputs.m_error_code = prop_error_code;
return m_outputs.m_error_code;
}
m_outputs.m_temp[C_sco2_cycle_core::HTR_HP_OUT] = m_co2_props.temp;
m_outputs.m_entr[C_sco2_cycle_core::HTR_HP_OUT] = m_co2_props.entr;
m_outputs.m_dens[C_sco2_cycle_core::HTR_HP_OUT] = m_co2_props.dens;
}
// Calculate total work and heat metrics
{
// Work
m_outputs.m_W_dot_mc = m_outputs.m_w_mc * m_outputs.m_m_dot_mc; //[kWe]
m_outputs.m_W_dot_rc = m_outputs.m_w_rc * m_outputs.m_m_dot_rc; //[kWe]
m_outputs.m_W_dot_t = m_outputs.m_w_t * m_outputs.m_m_dot_t; //[kWe]
m_outputs.m_W_dot_net = m_outputs.m_W_dot_mc + m_outputs.m_W_dot_rc + m_outputs.m_W_dot_t;
// Air Cooler (heat rejection unit)
m_outputs.m_W_dot_air_cooler = m_inputs.m_frac_fan_power * m_outputs.m_W_dot_net;
m_outputs.m_Q_dot_air_cooler = m_outputs.m_m_dot_mc * (m_outputs.m_enth[C_sco2_cycle_core::LTR_LP_OUT] - m_outputs.m_enth[C_sco2_cycle_core::MC_IN]);
// Total Heat Entering sco2
m_outputs.m_Q_dot_total = m_outputs.m_W_dot_net + m_outputs.m_Q_dot_air_cooler;
// LTR
m_outputs.m_Q_dot_LTR_LP = m_outputs.m_m_dot_t * (m_outputs.m_enth[C_sco2_cycle_core::HTR_LP_OUT] - m_outputs.m_enth[C_sco2_cycle_core::LTR_LP_OUT]);
m_outputs.m_Q_dot_LTR_HP = m_outputs.m_m_dot_mc * (m_outputs.m_enth[C_sco2_cycle_core::LTR_HP_OUT] - m_outputs.m_enth[C_sco2_cycle_core::MC_OUT]);
// LTR
m_outputs.m_Q_dot_HTR_LP = m_outputs.m_m_dot_t * (m_outputs.m_enth[C_sco2_cycle_core::TURB_OUT] - m_outputs.m_enth[C_sco2_cycle_core::HTR_LP_OUT]);
m_outputs.m_Q_dot_HTR_HP = m_outputs.m_m_dot_htr_hp * (m_outputs.m_enth[C_sco2_cycle_core::HTR_HP_OUT] - m_outputs.m_enth[C_sco2_cycle_core::MIXER_OUT]);
}
// Calculate Bypass Energy
{
// Set Bypass Temp based on HTR_HP_OUT
m_outputs.m_temp[C_sco2_cycle_core::BYPASS_OUT] = m_outputs.m_temp[C_sco2_cycle_core::HTR_HP_OUT] + m_inputs.m_dT_BP;
// Calculate BYPASS_OUT properties
int prop_error_code = CO2_TP(m_outputs.m_temp[C_sco2_cycle_core::BYPASS_OUT], m_outputs.m_pres[C_sco2_cycle_core::BYPASS_OUT], &m_co2_props);
if (prop_error_code != 0)
{
m_outputs.m_error_code = -1;
return m_outputs.m_error_code;
}
m_outputs.m_enth[C_sco2_cycle_core::BYPASS_OUT] = m_co2_props.enth;
m_outputs.m_entr[C_sco2_cycle_core::BYPASS_OUT] = m_co2_props.entr;
m_outputs.m_dens[C_sco2_cycle_core::BYPASS_OUT] = m_co2_props.dens;
// Calculate Heat Transfer in Bypass
m_outputs.m_Q_dot_BP = m_outputs.m_m_dot_bp * (m_outputs.m_enth[C_sco2_cycle_core::BYPASS_OUT] - m_outputs.m_enth[C_sco2_cycle_core::MIXER_OUT]);
}
// Simulate Mixer 2
{
// If Bypass and HTR have flow
if (m_inputs.m_bypass_frac >= 1e-12 && m_inputs.m_bypass_frac <= (1.0 - 1e-12))
{
m_outputs.m_enth[C_sco2_cycle_core::MIXER2_OUT] = (1.0 - m_inputs.m_bypass_frac) * m_outputs.m_enth[C_sco2_cycle_core::HTR_HP_OUT] +
m_inputs.m_bypass_frac * m_outputs.m_enth[C_sco2_cycle_core::BYPASS_OUT]; //[C_sco2_cycle_core::kJ/kg]
int prop_error_code = CO2_PH(m_outputs.m_pres[C_sco2_cycle_core::MIXER2_OUT], m_outputs.m_enth[C_sco2_cycle_core::MIXER2_OUT], &m_co2_props);
if (prop_error_code != 0)
{
m_outputs.m_error_code = -1;
return m_outputs.m_error_code;
}
m_outputs.m_temp[C_sco2_cycle_core::MIXER2_OUT] = m_co2_props.temp; //[C_sco2_cycle_core::K]
m_outputs.m_entr[C_sco2_cycle_core::MIXER2_OUT] = m_co2_props.entr; //[C_sco2_cycle_core::kJ/kg-K]
m_outputs.m_dens[C_sco2_cycle_core::MIXER2_OUT] = m_co2_props.dens; //[C_sco2_cycle_core::kg/m^3]
}
// Flow only through HTR
else if (m_inputs.m_bypass_frac <= (1.0 - 1e-12))
{
m_outputs.m_temp[C_sco2_cycle_core::MIXER2_OUT] = m_outputs.m_temp[C_sco2_cycle_core::HTR_HP_OUT]; //[C_sco2_cycle_core::K]
m_outputs.m_enth[C_sco2_cycle_core::MIXER2_OUT] = m_outputs.m_enth[C_sco2_cycle_core::HTR_HP_OUT]; //[C_sco2_cycle_core::kJ/kg]
m_outputs.m_entr[C_sco2_cycle_core::MIXER2_OUT] = m_outputs.m_entr[C_sco2_cycle_core::HTR_HP_OUT]; //[C_sco2_cycle_core::kJ/kg-K]
m_outputs.m_dens[C_sco2_cycle_core::MIXER2_OUT] = m_outputs.m_dens[C_sco2_cycle_core::HTR_HP_OUT]; //[C_sco2_cycle_core::kg/m^3]
}
// Flow only through Bypass
else
{
m_outputs.m_temp[C_sco2_cycle_core::MIXER2_OUT] = m_outputs.m_temp[C_sco2_cycle_core::BYPASS_OUT]; //[C_sco2_cycle_core::K]
m_outputs.m_enth[C_sco2_cycle_core::MIXER2_OUT] = m_outputs.m_enth[C_sco2_cycle_core::BYPASS_OUT]; //[C_sco2_cycle_core::kJ/kg]
m_outputs.m_entr[C_sco2_cycle_core::MIXER2_OUT] = m_outputs.m_entr[C_sco2_cycle_core::BYPASS_OUT]; //[C_sco2_cycle_core::kJ/kg-K]
m_outputs.m_dens[C_sco2_cycle_core::MIXER2_OUT] = m_outputs.m_dens[C_sco2_cycle_core::BYPASS_OUT]; //[C_sco2_cycle_core::kg/m^3]
}
}
// Calculate PHX Heat Transfer
{
m_outputs.m_Q_dot_PHX = m_outputs.m_m_dot_t * (m_outputs.m_enth[C_sco2_cycle_core::TURB_IN] - m_outputs.m_enth[C_sco2_cycle_core::MIXER2_OUT]);
}
// Back Calculate and Check values
{
// Bypass Temps
double bp_temp_in = m_outputs.m_temp[C_sco2_cycle_core::MIXER_OUT];
double bp_temp_out = m_outputs.m_temp[C_sco2_cycle_core::BYPASS_OUT];
double real_q_dot_total = m_outputs.m_W_dot_t + m_outputs.m_Q_dot_air_cooler;
double qSum = m_outputs.m_Q_dot_total;
double qSum_calc = m_outputs.m_Q_dot_BP + m_outputs.m_Q_dot_PHX;
int x = 0;
}
// HTF
{
// Check if HTF mdot is already assigned
if (m_inputs.m_set_HTF_mdot > 0)
{
// Mdot is Set
m_outputs.m_m_dot_HTF = m_inputs.m_set_HTF_mdot;
// Calculate PHX HTF Outlet Temperature
m_outputs.m_T_HTF_PHX_out = m_inputs.m_T_HTF_PHX_inlet - m_outputs.m_Q_dot_PHX / (m_outputs.m_m_dot_HTF * m_inputs.m_cp_HTF);
// Back Calculate PHX cold approach
m_outputs.m_HTF_PHX_cold_approach = m_outputs.m_T_HTF_PHX_out - m_outputs.m_temp[C_sco2_cycle_core::MIXER2_OUT];
}
else
{
// Use HTF Bypass cold approach to calculate PHX outlet Temperature
m_outputs.m_T_HTF_PHX_out = m_inputs.m_HTF_PHX_cold_approach_input + m_outputs.m_temp[C_sco2_cycle_core::MIXER2_OUT];
m_outputs.m_HTF_PHX_cold_approach = m_inputs.m_HTF_PHX_cold_approach_input;
// Calculate HTF mdot
m_outputs.m_m_dot_HTF = m_outputs.m_Q_dot_PHX / ((m_inputs.m_T_HTF_PHX_inlet - m_outputs.m_T_HTF_PHX_out) * m_inputs.m_cp_HTF);
}
// Calculate Bypass Out Temperature
m_outputs.m_T_HTF_BP_outlet = m_outputs.m_T_HTF_PHX_out - (m_outputs.m_Q_dot_BP / (m_outputs.m_m_dot_HTF * m_inputs.m_cp_HTF));
// Calculate HTF Bypass Cold Approach
m_outputs.m_HTF_BP_cold_approach = m_outputs.m_T_HTF_BP_outlet - m_outputs.m_temp[C_sco2_cycle_core::MIXER_OUT];
}
// Define Heat Exchangers and Air Cooler
{
// PHX
C_HeatExchanger::S_design_parameters PHX_des_par;
PHX_des_par.m_DP_design[0] = m_outputs.m_pres[C_sco2_cycle_core::MIXER2_OUT] - m_outputs.m_pres[C_sco2_cycle_core::TURB_IN];
PHX_des_par.m_DP_design[1] = 0.0;
PHX_des_par.m_m_dot_design[0] = m_outputs.m_m_dot_t;
PHX_des_par.m_m_dot_design[1] = 0.0;
PHX_des_par.m_Q_dot_design = m_outputs.m_m_dot_t * (m_outputs.m_enth[C_sco2_cycle_core::TURB_IN] - m_outputs.m_enth[C_sco2_cycle_core::MIXER2_OUT]);
m_outputs.m_PHX.initialize(PHX_des_par);
// BPX
C_HeatExchanger::S_design_parameters BPX_des_par;
BPX_des_par.m_DP_design[0] = m_outputs.m_pres[C_sco2_cycle_core::MIXER_OUT] - m_outputs.m_pres[C_sco2_cycle_core::BYPASS_OUT];
BPX_des_par.m_DP_design[1] = 0.0;
BPX_des_par.m_m_dot_design[0] = m_outputs.m_m_dot_bp;
BPX_des_par.m_m_dot_design[1] = 0.0;
BPX_des_par.m_Q_dot_design = m_outputs.m_m_dot_bp * (m_outputs.m_enth[C_sco2_cycle_core::BYPASS_OUT] - m_outputs.m_enth[C_sco2_cycle_core::MIXER_OUT]);
m_outputs.m_BPX.initialize(BPX_des_par);
// Air Cooler
C_HeatExchanger::S_design_parameters PC_des_par;
PC_des_par.m_DP_design[0] = 0.0;
PC_des_par.m_DP_design[1] = m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT] - m_outputs.m_pres[C_sco2_cycle_core::MC_IN];
PC_des_par.m_m_dot_design[0] = 0.0;
PC_des_par.m_m_dot_design[1] = m_outputs.m_m_dot_mc;
PC_des_par.m_Q_dot_design = m_outputs.m_m_dot_mc * (m_outputs.m_enth[C_sco2_cycle_core::LTR_LP_OUT] - m_outputs.m_enth[C_sco2_cycle_core::MC_IN]);
m_outputs.m_PC.initialize(PC_des_par);
}
// Calculate Thermal Efficiency
{
m_outputs.m_eta_thermal = m_outputs.m_W_dot_net / m_outputs.m_Q_dot_total;
}
m_outputs.m_error_code = 0;
return m_outputs.m_error_code;
}
int C_sco2_htrbp_core::finalize_design(C_sco2_cycle_core::S_design_solved& design_solved)
{
// Design Main Compressor
{
int mc_design_err = m_outputs.m_mc_ms.design_given_outlet_state(m_inputs.m_mc_comp_model_code, m_outputs.m_temp[C_sco2_cycle_core::MC_IN],
m_outputs.m_pres[C_sco2_cycle_core::MC_IN],
m_outputs.m_m_dot_mc,
m_outputs.m_temp[C_sco2_cycle_core::MC_OUT],
m_outputs.m_pres[C_sco2_cycle_core::MC_OUT],
m_inputs.m_des_tol);
if (mc_design_err != 0)
{
m_outputs.m_error_code = mc_design_err;
return m_outputs.m_error_code;
}
}
// Design Recompressor
if (m_inputs.m_recomp_frac > 0.01)
{
int rc_des_err = m_outputs.m_rc_ms.design_given_outlet_state(m_inputs.m_rc_comp_model_code, m_outputs.m_temp[C_sco2_cycle_core::LTR_LP_OUT],
m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT],
m_outputs.m_m_dot_rc,
m_outputs.m_temp[C_sco2_cycle_core::RC_OUT],
m_outputs.m_pres[C_sco2_cycle_core::RC_OUT],
m_inputs.m_des_tol);
if (rc_des_err != 0)
{
m_outputs.m_error_code = rc_des_err;
return m_outputs.m_error_code;
}
design_solved.m_is_rc = true;
}
else
{
design_solved.m_is_rc = false;
}
// Size Turbine
{
C_turbine::S_design_parameters t_des_par;
// Set turbine shaft speed
t_des_par.m_N_design = m_inputs.m_N_turbine;
t_des_par.m_N_comp_design_if_linked = m_outputs.m_mc_ms.get_design_solved()->m_N_design; //[rpm] m_mc.get_design_solved()->m_N_design;
// Turbine inlet state
t_des_par.m_P_in = m_outputs.m_pres[C_sco2_cycle_core::TURB_IN];
t_des_par.m_T_in = m_outputs.m_temp[C_sco2_cycle_core::TURB_IN];
t_des_par.m_D_in = m_outputs.m_dens[C_sco2_cycle_core::TURB_IN];
t_des_par.m_h_in = m_outputs.m_enth[C_sco2_cycle_core::TURB_IN];
t_des_par.m_s_in = m_outputs.m_entr[C_sco2_cycle_core::TURB_IN];
// Turbine outlet state
t_des_par.m_P_out = m_outputs.m_pres[C_sco2_cycle_core::TURB_OUT];
t_des_par.m_h_out = m_outputs.m_enth[C_sco2_cycle_core::TURB_OUT];
// Mass flow
t_des_par.m_m_dot = m_outputs.m_m_dot_t;
int turb_size_error_code = 0;
m_outputs.m_t.turbine_sizing(t_des_par, turb_size_error_code);
if (turb_size_error_code != 0)
{
m_outputs.m_error_code = turb_size_error_code;
return m_outputs.m_error_code;
}
}
// Design air cooler
{
// Structure for design parameters that are dependent on cycle design solution
C_CO2_to_air_cooler::S_des_par_cycle_dep s_air_cooler_des_par_dep;
// Set air cooler design parameters that are dependent on the cycle design solution
s_air_cooler_des_par_dep.m_T_hot_in_des = m_outputs.m_temp[C_sco2_cycle_core::LTR_LP_OUT]; // [K]
s_air_cooler_des_par_dep.m_P_hot_in_des = m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT]; // [kPa]
s_air_cooler_des_par_dep.m_m_dot_total = m_outputs.m_m_dot_mc; // [kg/s]
// This pressure drop is currently uncoupled from the cycle design
double cooler_deltaP = m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT] - m_outputs.m_pres[C_sco2_cycle_core::MC_IN]; // [kPa]
if (cooler_deltaP == 0.0)
s_air_cooler_des_par_dep.m_delta_P_des = m_inputs.m_deltaP_cooler_frac * m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT]; // [kPa]
else
s_air_cooler_des_par_dep.m_delta_P_des = cooler_deltaP; // [kPa]
s_air_cooler_des_par_dep.m_T_hot_out_des = m_outputs.m_temp[C_sco2_cycle_core::MC_IN]; // [K]
s_air_cooler_des_par_dep.m_W_dot_fan_des = m_inputs.m_frac_fan_power * m_outputs.m_W_dot_net / 1000.0; // [MWe]
// Structure for design parameters that are independent of cycle design solution
C_CO2_to_air_cooler::S_des_par_ind s_air_cooler_des_par_ind;
s_air_cooler_des_par_ind.m_T_amb_des = m_inputs.m_T_amb_des; // [K]
s_air_cooler_des_par_ind.m_elev = m_inputs.m_elevation; // [m]
s_air_cooler_des_par_ind.m_eta_fan = m_inputs.m_eta_fan; // [-]
s_air_cooler_des_par_ind.m_N_nodes_pass = m_inputs.m_N_nodes_pass; // [-]
if (m_inputs.m_is_des_air_cooler && std::isfinite(m_inputs.m_deltaP_cooler_frac) && std::isfinite(m_inputs.m_frac_fan_power)
&& std::isfinite(m_inputs.m_T_amb_des) && std::isfinite(m_inputs.m_elevation) && std::isfinite(m_inputs.m_eta_fan) && m_inputs.m_N_nodes_pass > 0)
{
m_outputs.mc_air_cooler.design_hx(s_air_cooler_des_par_ind, s_air_cooler_des_par_dep, m_inputs.m_des_tol);
}
}
// Get 'design_solved' structure from component classes
design_solved.ms_mc_ms_des_solved = *m_outputs.m_mc_ms.get_design_solved();
design_solved.ms_rc_ms_des_solved = *m_outputs.m_rc_ms.get_design_solved();
design_solved.ms_t_des_solved = *m_outputs.m_t.get_design_solved();
design_solved.ms_LTR_des_solved = m_outputs.mc_LT_recup.ms_des_solved;
design_solved.ms_HTR_des_solved = m_outputs.mc_HT_recup.ms_des_solved;
design_solved.ms_mc_air_cooler = *m_outputs.mc_air_cooler.get_design_solved();
// Set solved design point metrics
design_solved.m_temp = m_outputs.m_temp;
design_solved.m_pres = m_outputs.m_pres;
design_solved.m_enth = m_outputs.m_enth;
design_solved.m_entr = m_outputs.m_entr;
design_solved.m_dens = m_outputs.m_dens;
design_solved.m_eta_thermal = m_outputs.m_eta_thermal;
design_solved.m_W_dot_net = m_outputs.m_W_dot_net;
design_solved.m_m_dot_mc = m_outputs.m_m_dot_mc;
design_solved.m_m_dot_rc = m_outputs.m_m_dot_rc;
design_solved.m_m_dot_t = m_outputs.m_m_dot_t;
design_solved.m_recomp_frac = m_outputs.m_m_dot_rc / m_outputs.m_m_dot_t;
design_solved.m_bypass_frac = m_inputs.m_bypass_frac;
design_solved.m_UA_LTR = m_inputs.m_LTR_UA;
design_solved.m_UA_HTR = m_inputs.m_HTR_UA;
design_solved.m_W_dot_t = m_outputs.m_W_dot_t; //[kWe]
design_solved.m_W_dot_mc = m_outputs.m_W_dot_mc; //[kWe]
design_solved.m_W_dot_rc = m_outputs.m_W_dot_rc; //[kWe]
design_solved.m_W_dot_cooler_tot = m_outputs.mc_air_cooler.get_design_solved()->m_W_dot_fan * 1.E3; //[kWe] convert from MWe
return 0;
}
int C_sco2_htrbp_core::solve_HTR(double T_HTR_LP_OUT_guess, double* diff_T_HTR_LP_out)
{
m_outputs.m_w_rc = m_outputs.m_m_dot_t = m_outputs.m_m_dot_rc = m_outputs.m_m_dot_mc = m_outputs.m_Q_dot_LT = m_outputs.m_Q_dot_HT = std::numeric_limits<double>::quiet_NaN();
// Set temperature guess
m_outputs.m_temp[C_sco2_cycle_core::HTR_LP_OUT] = T_HTR_LP_OUT_guess; //[K]
// Solve HTR_LP_OUT properties
{
int prop_error_code = CO2_TP(m_outputs.m_temp[C_sco2_cycle_core::HTR_LP_OUT], m_outputs.m_pres[C_sco2_cycle_core::HTR_LP_OUT], &m_co2_props);
if (prop_error_code != 0)
{
*diff_T_HTR_LP_out = std::numeric_limits<double>::quiet_NaN();
return prop_error_code;
}
m_outputs.m_enth[C_sco2_cycle_core::HTR_LP_OUT] = m_co2_props.enth;
m_outputs.m_entr[C_sco2_cycle_core::HTR_LP_OUT] = m_co2_props.entr;
m_outputs.m_dens[C_sco2_cycle_core::HTR_LP_OUT] = m_co2_props.dens;
}
// Solve for the LTR solution
{
double T_LTR_LP_out_lower = m_outputs.m_temp[C_sco2_cycle_core::MC_OUT]; //[K] Coldest possible outlet temperature
double T_LTR_LP_out_upper = m_outputs.m_temp[C_sco2_cycle_core::HTR_LP_OUT]; //[K] Hottest possible outlet temperature
double T_LTR_LP_out_guess_upper = std::min(T_LTR_LP_out_upper, T_LTR_LP_out_lower + 15.0); //[K] There is nothing special about using 15 here...
double T_LTR_LP_out_guess_lower = std::min(T_LTR_LP_out_guess_upper * 0.99, T_LTR_LP_out_lower + 2.0); //[K] There is nothing special about using 2 here...
C_mono_htrbp_core_LTR_des LTR_des_eq(this);
C_monotonic_eq_solver LTR_des_solver(LTR_des_eq);
LTR_des_solver.settings(m_inputs.m_des_tol * m_outputs.m_temp[C_sco2_cycle_core::MC_IN], 1000, T_LTR_LP_out_lower,
T_LTR_LP_out_upper, false);
double T_LTR_LP_out_solved = std::numeric_limits<double>::quiet_NaN();
double tol_T_LTR_LP_out_solved = std::numeric_limits<double>::quiet_NaN();
int iter_T_LTR_LP_out = -1;
int T_LTR_LP_out_code = LTR_des_solver.solve(T_LTR_LP_out_guess_lower, T_LTR_LP_out_guess_upper, 0, T_LTR_LP_out_solved,
tol_T_LTR_LP_out_solved, iter_T_LTR_LP_out);
if (T_LTR_LP_out_code != C_monotonic_eq_solver::CONVERGED)
{
return 31;
}
}
// Know LTR performance so we can calculate the HP outlet (Energy balance on LTR HP stream)
{
m_outputs.m_enth[C_sco2_cycle_core::LTR_HP_OUT] = m_outputs.m_enth[C_sco2_cycle_core::MC_OUT] + m_outputs.m_Q_dot_LT / m_outputs.m_m_dot_mc; //[kJ/kg]
int prop_error_code = CO2_PH(m_outputs.m_pres[C_sco2_cycle_core::LTR_HP_OUT], m_outputs.m_enth[C_sco2_cycle_core::LTR_HP_OUT], &m_co2_props);
if (prop_error_code != 0)
{
*diff_T_HTR_LP_out = std::numeric_limits<double>::quiet_NaN();
return prop_error_code;
}
m_outputs.m_temp[C_sco2_cycle_core::LTR_HP_OUT] = m_co2_props.temp; //[K]
m_outputs.m_entr[C_sco2_cycle_core::LTR_HP_OUT] = m_co2_props.entr; //[kJ/kg-K]
m_outputs.m_dens[C_sco2_cycle_core::LTR_HP_OUT] = m_co2_props.dens; //[kg/m^3]
}
// Simulate the Mixer
if (m_inputs.m_recomp_frac >= 1.E-12)
{
m_outputs.m_enth[C_sco2_cycle_core::MIXER_OUT] = (1.0 - m_inputs.m_recomp_frac) * m_outputs.m_enth[C_sco2_cycle_core::LTR_HP_OUT]
+ m_inputs.m_recomp_frac * m_outputs.m_enth[C_sco2_cycle_core::RC_OUT]; //[kJ/kg]
int prop_error_code = CO2_PH(m_outputs.m_pres[C_sco2_cycle_core::MIXER_OUT], m_outputs.m_enth[C_sco2_cycle_core::MIXER_OUT], &m_co2_props);
if (prop_error_code != 0)
{
*diff_T_HTR_LP_out = std::numeric_limits<double>::quiet_NaN();
return prop_error_code;
}
m_outputs.m_temp[C_sco2_cycle_core::MIXER_OUT] = m_co2_props.temp; //[K]
m_outputs.m_entr[C_sco2_cycle_core::MIXER_OUT] = m_co2_props.entr; //[kJ/kg-K]
m_outputs.m_dens[C_sco2_cycle_core::MIXER_OUT] = m_co2_props.dens; //[kg/m^3]
}
else
{ // No recompressor, so no mixing required, and HTR HP inlet = LTR HP outlet
m_outputs.m_temp[C_sco2_cycle_core::MIXER_OUT] = m_outputs.m_temp[C_sco2_cycle_core::LTR_HP_OUT]; //[K]
m_outputs.m_enth[C_sco2_cycle_core::MIXER_OUT] = m_outputs.m_enth[C_sco2_cycle_core::LTR_HP_OUT]; //[kJ/kg]
m_outputs.m_entr[C_sco2_cycle_core::MIXER_OUT] = m_outputs.m_entr[C_sco2_cycle_core::LTR_HP_OUT]; //[kJ/kg-K]
m_outputs.m_dens[C_sco2_cycle_core::MIXER_OUT] = m_outputs.m_dens[C_sco2_cycle_core::LTR_HP_OUT]; //[kg/m^3]
}
// Solve Mass Flow rates for HTR_HP_OUT and Bypass
{
m_outputs.m_m_dot_bp = m_inputs.m_bypass_frac * m_outputs.m_m_dot_t;
m_outputs.m_m_dot_htr_hp = m_outputs.m_m_dot_t - m_outputs.m_m_dot_bp;
}
// Find the design solution of the HTR
double T_HTR_LP_out_calc = std::numeric_limits<double>::quiet_NaN();
{
// If there is no flow through HTR HP side
if (m_outputs.m_m_dot_htr_hp < 1e-12)
{
m_outputs.m_Q_dot_HT = 0;
T_HTR_LP_out_calc = m_outputs.m_temp[C_sco2_cycle_core::TURB_OUT];
}
// If there is flow through HTR HP side
else
{
m_outputs.mc_HT_recup.design_for_target__calc_outlet(m_inputs.m_HTR_target_code,
m_inputs.m_HTR_UA, m_inputs.m_HTR_min_dT, m_inputs.m_HTR_eff_target,
m_inputs.m_HTR_eff_max,
m_outputs.m_temp[C_sco2_cycle_core::MIXER_OUT], m_outputs.m_pres[C_sco2_cycle_core::MIXER_OUT], m_outputs.m_m_dot_htr_hp, m_outputs.m_pres[C_sco2_cycle_core::HTR_HP_OUT],
m_outputs.m_temp[C_sco2_cycle_core::TURB_OUT], m_outputs.m_pres[C_sco2_cycle_core::TURB_OUT], m_outputs.m_m_dot_t, m_outputs.m_pres[C_sco2_cycle_core::HTR_LP_OUT],
m_inputs.m_des_tol,
m_outputs.m_Q_dot_HT, m_outputs.m_temp[C_sco2_cycle_core::HTR_HP_OUT], T_HTR_LP_out_calc);
}
}
*diff_T_HTR_LP_out = T_HTR_LP_out_calc - T_HTR_LP_OUT_guess;
return 0;
}
int C_sco2_htrbp_core::solve_LTR(double T_LTR_LP_OUT_guess, double* diff_T_LTR_LP_out)
{
m_outputs.m_w_rc = m_outputs.m_m_dot_t = m_outputs.m_m_dot_rc = m_outputs.m_m_dot_mc = m_outputs.m_Q_dot_LT = m_outputs.m_Q_dot_HT = std::numeric_limits<double>::quiet_NaN();
// Set LTR_LP_OUT guess
m_outputs.m_temp[C_sco2_cycle_core::LTR_LP_OUT] = T_LTR_LP_OUT_guess;
// First, solve the recompressor model as necessary
if (m_inputs.m_recomp_frac >= 1.E-12)
{
double eta_rc_isen = std::numeric_limits<double>::quiet_NaN();
if (m_inputs.m_eta_rc < 0.0) // recalculate isen. efficiency of recompressor because inlet temp changes
{
int rc_error_code = 0;
isen_eta_from_poly_eta(m_outputs.m_temp[C_sco2_cycle_core::LTR_LP_OUT], m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT],
m_outputs.m_pres[C_sco2_cycle_core::RC_OUT], std::abs(m_inputs.m_eta_rc), true,
rc_error_code, eta_rc_isen);
if (rc_error_code != 0)
{
*diff_T_LTR_LP_out = std::numeric_limits<double>::quiet_NaN();
return rc_error_code;
}
}
else
{
eta_rc_isen = m_inputs.m_eta_rc;
}
int rc_error_code = 0;
calculate_turbomachinery_outlet_1(m_outputs.m_temp[C_sco2_cycle_core::LTR_LP_OUT], m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT], m_outputs.m_pres[C_sco2_cycle_core::RC_OUT], eta_rc_isen, true, rc_error_code,
m_outputs.m_enth[C_sco2_cycle_core::LTR_LP_OUT], m_outputs.m_entr[C_sco2_cycle_core::LTR_LP_OUT], m_outputs.m_dens[C_sco2_cycle_core::LTR_LP_OUT], m_outputs.m_temp[C_sco2_cycle_core::RC_OUT], m_outputs.m_enth[C_sco2_cycle_core::RC_OUT],
m_outputs.m_entr[C_sco2_cycle_core::RC_OUT], m_outputs.m_dens[C_sco2_cycle_core::RC_OUT], m_outputs.m_w_rc);
if (rc_error_code != 0)
{
*diff_T_LTR_LP_out = std::numeric_limits<double>::quiet_NaN();
return rc_error_code;
}
}
else
{
m_outputs.m_w_rc = 0.0; // no recompressor
int prop_error_code = CO2_TP(m_outputs.m_temp[C_sco2_cycle_core::LTR_LP_OUT], m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT], &m_co2_props);
if (prop_error_code != 0)
{
*diff_T_LTR_LP_out = std::numeric_limits<double>::quiet_NaN();
return prop_error_code;
}
m_outputs.m_enth[C_sco2_cycle_core::LTR_LP_OUT] = m_co2_props.enth;
m_outputs.m_entr[C_sco2_cycle_core::LTR_LP_OUT] = m_co2_props.entr;
m_outputs.m_dens[C_sco2_cycle_core::LTR_LP_OUT] = m_co2_props.dens;
m_outputs.m_temp[C_sco2_cycle_core::RC_OUT] = m_outputs.m_temp[C_sco2_cycle_core::LTR_LP_OUT];
m_outputs.m_enth[C_sco2_cycle_core::RC_OUT] = m_outputs.m_enth[C_sco2_cycle_core::LTR_LP_OUT];
m_outputs.m_entr[C_sco2_cycle_core::RC_OUT] = m_outputs.m_entr[C_sco2_cycle_core::LTR_LP_OUT];
m_outputs.m_dens[C_sco2_cycle_core::RC_OUT] = m_outputs.m_dens[C_sco2_cycle_core::LTR_LP_OUT];
}
// Solve Mass Flow Rates
{
m_outputs.m_m_dot_t = m_inputs.m_W_dot_net_design / ((m_outputs.m_w_mc * (1.0 - m_inputs.m_recomp_frac) +
m_outputs.m_w_rc * m_inputs.m_recomp_frac + m_outputs.m_w_t) * m_inputs.m_eta_generator); //[C_sco2_cycle_core::kg/s]
m_outputs.m_m_dot_rc = m_outputs.m_m_dot_t * m_inputs.m_recomp_frac; //[C_sco2_cycle_core::kg/s]
m_outputs.m_m_dot_mc = m_outputs.m_m_dot_t - m_outputs.m_m_dot_rc;
}
// Solve LTR
*diff_T_LTR_LP_out = std::numeric_limits<double>::quiet_NaN();
double T_LTR_LP_out_calc = std::numeric_limits<double>::quiet_NaN();
{
m_outputs.mc_LT_recup.design_for_target__calc_outlet(m_inputs.m_LTR_target_code,
m_inputs.m_LTR_UA, m_inputs.m_LTR_min_dT, m_inputs.m_LTR_eff_target,
m_inputs.m_LTR_eff_max,
m_outputs.m_temp[C_sco2_cycle_core::MC_OUT], m_outputs.m_pres[C_sco2_cycle_core::MC_OUT], m_outputs.m_m_dot_mc, m_outputs.m_pres[C_sco2_cycle_core::LTR_HP_OUT],
m_outputs.m_temp[C_sco2_cycle_core::HTR_LP_OUT], m_outputs.m_pres[C_sco2_cycle_core::HTR_LP_OUT], m_outputs.m_m_dot_t, m_outputs.m_pres[C_sco2_cycle_core::LTR_LP_OUT],
m_inputs.m_des_tol,
m_outputs.m_Q_dot_LT, m_outputs.m_temp[C_sco2_cycle_core::LTR_HP_OUT], T_LTR_LP_out_calc);
}
*diff_T_LTR_LP_out = T_LTR_LP_out_calc - T_LTR_LP_OUT_guess;
return 0;
}
void C_sco2_htrbp_core::reset()
{
this->m_inputs = S_sco2_htrbp_in();
this->m_outputs.Init();
}
// ********************************************************************************** END C_sco2_htrbp_core
// ********************************************************************************** PRIVATE C_HTRBypass_Cycle (: C_sco2_cycle_core)
/// <summary>
/// Core function to optimize cycle (fixed total UA)
/// </summary>
void C_HTRBypass_Cycle::auto_opt_design_core(int& error_code)
{
// Reset optimal htrbp model
m_optimal_htrbp_core.reset();
// Check that simple/recomp flag is set
if (ms_auto_opt_des_par.m_is_recomp_ok < -1.0 || (ms_auto_opt_des_par.m_is_recomp_ok > 0 &&
ms_auto_opt_des_par.m_is_recomp_ok != 1.0 && ms_auto_opt_des_par.m_is_recomp_ok != 2.0))
{
throw(C_csp_exception("C_RecompCycle::auto_opt_design_core(...) requires that ms_auto_opt_des_par.m_is_recomp_ok"
" is either between -1 and 0 (fixed recompression fraction) or equal to 1 (recomp allowed)\n"));
}
// Create 'ms_opt_des_par' for Design Variables
S_opt_design_parameters opt_par;
{
// Max Pressure
double best_P_high = m_P_high_limit; //[kPa]
double PR_mc_guess = 2.5; //[-]
opt_par.m_fixed_P_mc_out = ms_auto_opt_des_par.m_fixed_P_mc_out; //[-]
if (!opt_par.m_fixed_P_mc_out)
{
double P_low_limit = std::min(m_P_high_limit, std::max(10.E3, m_P_high_limit * 0.2)); //[kPa]
//best_P_high = fminbr(P_low_limit, m_P_high_limit, &fmin_cb_opt_des_fixed_P_high, this, 1.0);
best_P_high = m_P_high_limit;
}
opt_par.m_P_mc_out_guess = best_P_high; //[kPa]
//ms_opt_des_par.m_fixed_P_mc_out = true;
// Pressure Ratio (min pressure)
opt_par.m_fixed_PR_HP_to_LP = ms_auto_opt_des_par.m_fixed_PR_HP_to_LP; //[-]
if (opt_par.m_fixed_PR_HP_to_LP)
{
opt_par.m_PR_HP_to_LP_guess = ms_auto_opt_des_par.m_PR_HP_to_LP_guess; //[-]
}
else
{
opt_par.m_PR_HP_to_LP_guess = PR_mc_guess; //[-]
}
// Is recompression fraction fixed or optimized?
if (ms_auto_opt_des_par.m_is_recomp_ok <= 0.0)
{ // fixed
opt_par.m_recomp_frac_guess = std::abs(ms_auto_opt_des_par.m_is_recomp_ok);
opt_par.m_fixed_recomp_frac = true;
}
else
{ // optimized
opt_par.m_recomp_frac_guess = 0.3;
opt_par.m_fixed_recomp_frac = false;
}
// Is bypass fraction fixed or optimized?
if (ms_auto_opt_des_par.m_is_bypass_ok <= 0.0)
{ // fixed
opt_par.m_bypass_frac_guess = std::abs(ms_auto_opt_des_par.m_is_bypass_ok);
opt_par.m_fixed_bypass_frac = true;
}
else
{ // optimized
opt_par.m_bypass_frac_guess = 0.3;
opt_par.m_fixed_bypass_frac = false;
}
// LTR HTR UA Ratio
opt_par.m_LT_frac_guess = 0.5;
opt_par.m_fixed_LT_frac = false;
if (ms_auto_opt_des_par.m_LTR_target_code != NS_HX_counterflow_eqs::OPTIMIZE_UA || ms_auto_opt_des_par.m_HTR_target_code != NS_HX_counterflow_eqs::OPTIMIZE_UA)
{
opt_par.m_fixed_LT_frac = true;
}
// Set Design Method
if (opt_par.m_fixed_LT_frac == true)
opt_par.m_design_method = 3;
else
opt_par.m_design_method = 2;
}
// Find optimal inputs
C_sco2_htrbp_core::S_sco2_htrbp_in optimal_inputs_out;
error_code = optimize_bp(ms_auto_opt_des_par, opt_par, optimal_inputs_out);
if (error_code != 0)
return;
// Run Optimal Case
m_optimal_htrbp_core.set_inputs(optimal_inputs_out);
error_code = m_optimal_htrbp_core.solve();
if (error_code != 0)
return;
// don't size system if eta is terrible
//if (m_optimal_htrbp_core.m_outputs.m_eta_thermal < 0.15)
//{
// error_code = (int)C_sco2_cycle_core::E_cycle_error_msg::E_ETA_THRESHOLD;
// return;
//}
// Finalize Design (pass in reference to solved parameters)
error_code = m_optimal_htrbp_core.finalize_design(ms_des_solved);
}
/// <summary>
/// Core function to optimize cycle for target eta (variable total UA)
/// </summary>
void C_HTRBypass_Cycle::auto_opt_design_hit_eta_core(int& error_code, const double eta_thermal_target)
{
// Create 'ms_opt_des_par' for Design Variables
S_opt_design_parameters opt_par;
{
// Target Thermal Efficiency
opt_par.m_eta_thermal_target = eta_thermal_target;
// Max Pressure
double best_P_high = m_P_high_limit; //[kPa]
double PR_mc_guess = 2.5; //[-]
opt_par.m_fixed_P_mc_out = ms_auto_opt_des_par.m_fixed_P_mc_out; //[-]
if (!opt_par.m_fixed_P_mc_out)
{
double P_low_limit = std::min(m_P_high_limit, std::max(10.E3, m_P_high_limit * 0.2)); //[kPa]
//best_P_high = fminbr(P_low_limit, m_P_high_limit, &fmin_cb_opt_des_fixed_P_high, this, 1.0);
best_P_high = m_P_high_limit;
}
opt_par.m_P_mc_out_guess = best_P_high; //[kPa]
//ms_opt_des_par.m_fixed_P_mc_out = true;
// Pressure Ratio (min pressure)
opt_par.m_fixed_PR_HP_to_LP = ms_auto_opt_des_par.m_fixed_PR_HP_to_LP; //[-]
if (opt_par.m_fixed_PR_HP_to_LP)
{
opt_par.m_PR_HP_to_LP_guess = ms_auto_opt_des_par.m_PR_HP_to_LP_guess; //[-]
}
else
{
opt_par.m_PR_HP_to_LP_guess = PR_mc_guess; //[-]
}
// Is recompression fraction fixed or optimized?
if (ms_auto_opt_des_par.m_is_recomp_ok <= 0.0)
{ // fixed
opt_par.m_recomp_frac_guess = std::abs(ms_auto_opt_des_par.m_is_recomp_ok);
opt_par.m_fixed_recomp_frac = true;
}
else
{ // optimized
opt_par.m_recomp_frac_guess = 0.3;
opt_par.m_fixed_recomp_frac = false;
}
// Is bypass fraction fixed or optimized?
if (ms_auto_opt_des_par.m_is_bypass_ok <= 0.0)
{ // fixed
opt_par.m_bypass_frac_guess = std::abs(ms_auto_opt_des_par.m_is_bypass_ok);
opt_par.m_fixed_bypass_frac = true;
}