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Remove serial tanks option for heattrap tes
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@taylorbrown75
taylorbrown75 committed Mar 26, 2024
1 parent d291663 commit 284b73d
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Showing 4 changed files with 37 additions and 132 deletions.
7 changes: 6 additions & 1 deletion ssc/cmod_csp_subcomponent.cpp
View file
Expand Up @@ -220,6 +220,12 @@ class cm_csp_subcomponent : public compute_module
tes_diams.assign(tes_diams_val, 1);
}

bool tanks_in_parallel = as_boolean("tanks_in_parallel");
if (tanks_in_parallel == false)
{
throw exec_error("csp_subcomponent", "TES model requires tanks in parallel");
}

storage_NT = C_csp_NTHeatTrap_tes(
as_integer("Fluid"),
as_matrix("field_fl_props"),
Expand All @@ -245,7 +251,6 @@ class cm_csp_subcomponent : public compute_module
as_double("h_tank_min"),
as_double("init_hot_htf_percent"),
as_double("pb_pump_coef"),
as_boolean("tanks_in_parallel"),
as_double("tes_tank_cp") * 1000, // convert to J/kgK
as_double("tes_tank_dens"),
as_double("tes_tank_thick"),
Expand Down
7 changes: 6 additions & 1 deletion ssc/cmod_trough_physical.cpp
View file
Expand Up @@ -1313,6 +1313,12 @@ class cm_trough_physical : public compute_module
//double tes_tankcp = 1200; // J/kg K
//double tes_tankdens = 8000; // kg/m3

bool tanks_in_parallel = as_boolean("tanks_in_parallel");
if (tanks_in_parallel == false)
{
throw exec_error("trough_physical", "TES model requires tanks in parallel");
}

storage_NT = C_csp_NTHeatTrap_tes(
c_trough.m_Fluid,
c_trough.m_field_fl_props,
Expand All @@ -1338,7 +1344,6 @@ class cm_trough_physical : public compute_module
as_double("h_tank_min"),
as_double("init_hot_htf_percent"),
as_double("pb_pump_coef"),
as_boolean("tanks_in_parallel"),
as_double("tes_tank_cp") * 1000, // convert to J/kgK
as_double("tes_tank_dens"),
as_double("tes_tank_thick"),
Expand Down
151 changes: 24 additions & 127 deletions tcs/csp_solver_NTHeatTrap_tes.cpp
View file
Expand Up @@ -787,7 +787,6 @@ C_csp_NTHeatTrap_tes::C_csp_NTHeatTrap_tes(
double h_tank_min, // [m] Minimum allowable HTF height in storage tank
double f_V_hot_ini, // [%] Initial fraction of available volume that is hot
double htf_pump_coef, // [kW/kg/s] Pumping power to move 1 kg/s of HTF through sink
bool tanks_in_parallel, // [-] Whether the tanks are in series or parallel with the external system. Series means external htf must go through storage tanks.
double tank_wall_cp, // [J/kg-K] Tank wall specific heat
double tank_wall_dens, // [kg/m3] Tank wall density
double tank_wall_thick, // [m] Tank wall thickness
Expand Down Expand Up @@ -816,7 +815,6 @@ C_csp_NTHeatTrap_tes::C_csp_NTHeatTrap_tes(
m_cold_tank_Thtr(cold_tank_Thtr), m_cold_tank_max_heat(cold_tank_max_heat), m_dt_hot(dt_hot), m_T_cold_des(T_cold_des),
m_T_hot_des(T_hot_des), m_T_tank_hot_ini(T_tank_hot_ini), m_T_tank_cold_ini(T_tank_cold_ini),
m_h_tank_min(h_tank_min), m_f_V_hot_ini(f_V_hot_ini), m_htf_pump_coef(htf_pump_coef),
tanks_in_parallel(tanks_in_parallel),
m_tank_wall_cp(tank_wall_cp), m_tank_wall_dens(tank_wall_dens), m_tank_wall_thick(tank_wall_thick), m_nstep(nstep),
m_piston_loss_poly(piston_loss_poly),
V_tes_des(V_tes_des), calc_design_pipe_vals(calc_design_pipe_vals), m_tes_pump_coef(tes_pump_coef),
Expand Down Expand Up @@ -941,7 +939,7 @@ void C_csp_NTHeatTrap_tes::init(const C_csp_tes::S_csp_tes_init_inputs init_inpu
m_is_cr_to_cold_tank_allowed = false;
}
else {
m_is_cr_to_cold_tank_allowed = true;
throw C_csp_exception("Tank model must be in parallel");
}

// Calculate thermal power to PC at design
Expand Down Expand Up @@ -1173,6 +1171,27 @@ int C_csp_NTHeatTrap_tes::solve_tes_off_design(double timestep /*s*/, double T_
double& T_sink_htf_in_hot /*K*/, double& T_cr_in_cold /*K*/,
C_csp_tes::S_csp_tes_outputs& s_outputs) //, C_csp_solver_htf_state & s_tes_ch_htf, C_csp_solver_htf_state & s_tes_dc_htf)
{
// DEBUG
if (true)
{
double mdot_from_FIELD_to_HOT_TES = m_dot_cr_to_cv_hot;
double mdot_PC_HOT_IN = m_dot_cv_hot_to_sink;
double mdot_FIELD_to_COLD_TES = m_dot_cr_to_cv_cold;

if ((mdot_from_FIELD_to_HOT_TES > 0 && mdot_PC_HOT_IN > 0)
&& (std::abs(mdot_from_FIELD_to_HOT_TES - mdot_PC_HOT_IN) > 0.01))
{
int asdfasg = 0;
}
}








// Enthalpy balance on inlet to cold cv
double T_htf_cold_cv_in = T_sink_out_cold; //[K]
double m_dot_total_to_cv_cold = m_dot_cv_hot_to_sink + m_dot_cr_to_cv_cold; //[kg/s]
Expand Down Expand Up @@ -1223,16 +1242,7 @@ int C_csp_NTHeatTrap_tes::solve_tes_off_design(double timestep /*s*/, double T_
}
else
{ // Serial configuration


m_dot_cr_to_tes_hot = m_dot_cr_to_cv_hot; //[kg/s]
m_dot_cr_to_tes_cold = m_dot_cr_to_cv_cold; //[kg/s]
m_dot_tes_hot_out = m_dot_cv_hot_to_sink; //[kg/s]
m_dot_pc_to_tes_cold = m_dot_cv_hot_to_sink; //[kg/s]
m_dot_tes_cold_out = m_dot_cr_to_cv_hot + m_dot_cr_to_cv_cold; //[kg/s]
m_dot_tes_cold_in = m_dot_total_to_cv_cold; //[kg/s]
m_dot_src_to_sink = 0.0; //[kg/s]
m_dot_sink_to_src = 0.0; //[kg/s]
throw C_csp_exception("Tank model must be in parallel");
}

double q_dot_heater = std::numeric_limits<double>::quiet_NaN(); //[MWe] Heating power required to keep tanks at a minimum temperature
Expand Down Expand Up @@ -1310,120 +1320,7 @@ int C_csp_NTHeatTrap_tes::solve_tes_off_design(double timestep /*s*/, double T_
}
else // Serial tank operation
{


// Inputs are:
// 1) Mass flow rate of HTF from source to hot tank
// 2) Mass flow rate of HTF from source to cold tank
// 3) Mass flow rate of HTF from hot tank to sink
// 4) Temperature of HTF leaving source and entering hot tank
// 5) Temperature of HTF leaving the sink and entering the cold tank

double q_dot_ch_est, m_dot_tes_ch_max, T_cold_to_src_est;
q_dot_ch_est = m_dot_tes_ch_max = T_cold_to_src_est = std::numeric_limits<double>::quiet_NaN();
charge_avail_est(T_cr_out_hot, timestep, q_dot_ch_est, m_dot_tes_ch_max, T_cold_to_src_est);

if (m_dot_cr_to_cv_hot > m_dot_cv_hot_to_sink && std::max(1.E-4, (m_dot_cr_to_cv_hot - m_dot_cv_hot_to_sink)) > 1.0001 * std::max(1.E-4, m_dot_tes_ch_max))
{
q_dot_heater = std::numeric_limits<double>::quiet_NaN();
m_dot_cold_tank_to_hot_tank = std::numeric_limits<double>::quiet_NaN();
W_dot_rhtf_pump = std::numeric_limits<double>::quiet_NaN();
q_dot_loss = std::numeric_limits<double>::quiet_NaN();
q_dot_dc_to_htf = std::numeric_limits<double>::quiet_NaN();
q_dot_ch_from_htf = std::numeric_limits<double>::quiet_NaN();
T_hot_ave = std::numeric_limits<double>::quiet_NaN();
T_cold_ave = std::numeric_limits<double>::quiet_NaN();
T_hot_final = std::numeric_limits<double>::quiet_NaN();
T_cold_final = std::numeric_limits<double>::quiet_NaN();

return -1;
}

double q_dot_dc_est, m_dot_tes_dc_max, T_hot_to_pc_est;
q_dot_dc_est = m_dot_tes_dc_max = T_hot_to_pc_est = std::numeric_limits<double>::quiet_NaN();
// Use temperature downstream of sink-out and cr-to-cold-tank mixer
discharge_avail_est(T_htf_cold_cv_in, timestep, q_dot_dc_est, m_dot_tes_dc_max, T_hot_to_pc_est);

// If mass flow into the cold tank *from the sink* is greater than mass flow going from cold tank to source to hot tank
if (m_dot_cv_hot_to_sink > m_dot_cr_to_cv_hot && std::max(1.E-4, (m_dot_cv_hot_to_sink - m_dot_cr_to_cv_hot)) > 1.0001 * std::max(1.E-4, m_dot_tes_dc_max))
{
q_dot_heater = std::numeric_limits<double>::quiet_NaN();
m_dot_cold_tank_to_hot_tank = std::numeric_limits<double>::quiet_NaN();
W_dot_rhtf_pump = std::numeric_limits<double>::quiet_NaN();
q_dot_loss = std::numeric_limits<double>::quiet_NaN();
q_dot_dc_to_htf = std::numeric_limits<double>::quiet_NaN();
q_dot_ch_from_htf = std::numeric_limits<double>::quiet_NaN();
T_hot_ave = std::numeric_limits<double>::quiet_NaN();
T_cold_ave = std::numeric_limits<double>::quiet_NaN();
T_hot_final = std::numeric_limits<double>::quiet_NaN();
T_cold_final = std::numeric_limits<double>::quiet_NaN();

return -2;
}

// serial operation constrained to direct configuration, so HTF leaving TES must pass through another plant component
m_dot_cold_tank_to_hot_tank = 0.0; //[kg/s]

double q_heater_hot, q_dot_loss_hot, q_heater_cold, q_dot_loss_cold;
q_heater_hot = q_dot_loss_hot = q_heater_cold = q_dot_loss_cold = std::numeric_limits<double>::quiet_NaN();

double T_hot_prev = mc_hot_tank_NT.get_m_T_prev();
double T_cold_prev = mc_cold_tank_NT.get_m_T_prev();

// Call energy balance on hot tank discharge to get average outlet temperature over timestep
mc_hot_tank_NT.energy_balance_iterated(timestep, m_dot_cr_to_cv_hot, m_dot_cv_hot_to_sink,
T_cr_out_hot, T_amb,
T_cold_prev, T_cold_prev,
T_sink_htf_in_hot, q_heater_hot, q_dot_loss_hot, q_dot_out_hot);

/*mc_hot_tank_NT.energy_balance(timestep, m_dot_cr_to_cv_hot, m_dot_cv_hot_to_sink,
T_cr_out_hot, T_amb,
T_cold_prev,
T_sink_htf_in_hot, q_heater_hot, q_dot_loss_hot);*/

// Call energy balance on cold tank charge to track tank mass and temperature
// Use mass flow and temperature downstream of sink-out and cr-to-cold-tank mixer
mc_cold_tank_NT.energy_balance_iterated(timestep, m_dot_total_to_cv_cold, m_dot_cv_cold_to_cr,
T_htf_cold_cv_in, T_amb,
T_hot_prev, T_hot_prev,
T_cr_in_cold, q_heater_cold, q_dot_loss_cold, q_dot_out_cold);

/*mc_cold_tank_NT.energy_balance(timestep, m_dot_total_to_cv_cold, m_dot_cv_cold_to_cr,
T_htf_cold_cv_in, T_amb,
T_hot_prev,
T_cr_in_cold, q_heater_cold, q_dot_loss_cold);*/

// Set output structure
q_dot_heater = q_heater_cold + q_heater_hot; //[MWt]

W_dot_rhtf_pump = 0; //[MWe] Tank-to-tank pumping power

q_dot_loss = q_dot_loss_cold + q_dot_loss_hot; //[MWt]
q_dot_ch_from_htf = 0.0; //[MWt]
T_hot_ave = T_sink_htf_in_hot; //[K]
T_cold_ave = T_cr_in_cold; //[K]
T_hot_final = mc_hot_tank_NT.get_m_T_calc(); //[K]
T_cold_final = mc_cold_tank_NT.get_m_T_calc(); //[K]

// Net TES discharge
double cp_field = mc_external_htfProps.Cp_ave(T_cold_ave, T_cr_out_hot);
double cp_cycle = mc_store_htfProps.Cp_ave(T_htf_cold_cv_in, T_hot_ave);
double q_dot_tes_net_discharge = (cp_field * (m_dot_tes_cold_out * T_cold_ave - m_dot_cr_to_tes_hot * T_cr_out_hot)
+ cp_cycle * (m_dot_tes_hot_out * T_hot_ave - m_dot_total_to_cv_cold * T_htf_cold_cv_in)) / 1000.0; //[MWt]

if (m_dot_cv_hot_to_sink >= m_dot_cr_to_cv_hot)
{
q_dot_ch_from_htf = 0.0;

q_dot_dc_to_htf = q_dot_tes_net_discharge; //[MWt]
}
else
{
q_dot_dc_to_htf = 0.0;

q_dot_ch_from_htf = -q_dot_tes_net_discharge; //[MWt]
}

throw C_csp_exception("Tank model must be in parallel");
}

// TOTAL Energy Balance for total system here
Expand Down
4 changes: 1 addition & 3 deletions tcs/csp_solver_NTHeatTrap_tes.h
View file
Expand Up @@ -264,7 +264,7 @@ class C_csp_NTHeatTrap_tes : public C_csp_tes
double m_htf_pump_coef; //[kW/kg/s] Pumping power to move 1 kg/s of HTF through sink
double m_tes_pump_coef; //[kW/kg/s] Pumping power to move 1 kg/s of HTF through tes loop
double eta_pump; //[-] Pump efficiency, for newer pumping calculations
bool tanks_in_parallel; //[-] Whether the tanks are in series or parallel with the external system. Series means external htf must go through storage tanks.
bool tanks_in_parallel; //[-] Whether the tanks are in series or parallel with the external system. ALWAYS TRUE for NT Heat Trap
bool has_hot_tank_bypass; //[-] True if the bypass valve causes the external htf to bypass just the hot tank and enter the cold tank before flowing back to the external system.
double T_tank_hot_inlet_min; //[C] Minimum external htf temperature that may enter the hot tank
double V_tes_des; //[m/s] Design-point velocity for sizing the diameters of the TES piping
Expand Down Expand Up @@ -310,8 +310,6 @@ class C_csp_NTHeatTrap_tes : public C_csp_tes
double h_tank_min, // [m] Minimum allowable HTF height in storage tank
double f_V_hot_ini, // [%] Initial fraction of available volume that is hot
double htf_pump_coef, // [kW/kg/s] Pumping power to move 1 kg/s of HTF through sink
bool tanks_in_parallel, // [-] Whether the tanks are in series or parallel with the external system. Series means external htf must go through storage tanks.

double tank_wall_cp, // [J/kg-K] Tank wall specific heat
double tank_wall_dens, // [kg/m3] Tank wall density
double tank_wall_thick = 0, // [m] Tank wall thickness
Expand Down

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