Skip to content

Fix SSC 621 - cycle degradation penalty is nan or zero #627

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
brtietz merged 1 commit into from
Oct 28, 2021
Merged

Fix SSC 621 - cycle degradation penalty is nan or zero #627

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
2 changes: 1 addition & 1 deletion shared/lib_battery_lifetime_lmolto.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -182,5 +182,5 @@ void lifetime_lmolto_t::replaceBattery(double percent_to_replace) {
}

double lifetime_lmolto_t::estimateCycleDamage() {
return state->lmo_lto->dq_relative_cyc / (double)state->n_cycles;
return state->lmo_lto->dq_relative_cyc / fmax(1.0, (double)state->n_cycles);
}
4 changes: 2 additions & 2 deletions shared/lib_battery_lifetime_nmc.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -229,8 +229,8 @@ void lifetime_nmc_t::runLifetimeModels(size_t _, bool charge_changed, double pre

double lifetime_nmc_t::estimateCycleDamage() {
// Use cumulative damage from cycling and average it over elapsed cycles
double QLi_cycle_damage = state->nmc_li_neg->dq_relative_li2 / (double)state->n_cycles;
double QNeg_cycle_damage = state->nmc_li_neg->dq_relative_neg / (double)state->n_cycles;
double QLi_cycle_damage = state->nmc_li_neg->dq_relative_li2 / fmax(1.0, (double)state->n_cycles); // fmax eliminates divide by zero error on first cycle
double QNeg_cycle_damage = state->nmc_li_neg->dq_relative_neg / fmax(1.0, (double)state->n_cycles);
return fmax(QLi_cycle_damage, QNeg_cycle_damage) * 100;
}

Expand Down
10 changes: 9 additions & 1 deletion ssc/cmod_battery.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -191,6 +191,9 @@ var_info vtab_battery_inputs[] = {

{ SSC_INPUT, SSC_NUMBER, "inflation_rate", "Inflation rate", "%", "", "Lifetime", "?=0", "MIN=-99", "" },
{ SSC_INPUT, SSC_ARRAY, "load_escalation", "Annual load escalation", "%/year", "", "Load", "?=0", "", "" },
{ SSC_INPUT, SSC_ARRAY, "om_batt_replacement_cost" , "Replacement cost 1" , "$/kWh" , "" , "System Costs" , "?=0.0" , "" , "" },
{ SSC_INPUT, SSC_NUMBER, "om_replacement_cost_escal" , "Replacement cost escalation" , "%/year" , "" , "System Costs" , "?=0.0" , "" , "" },

Comment on lines +194 to +196
Copy link
Collaborator

@mjprilliman mjprilliman Oct 28, 2021

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Why do these need to be in the cmod_battery vartable rather than in vtab_oandm in common.cpp?

Copy link
Collaborator Author

@brtietz brtietz Oct 28, 2021

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The battery compute modules don't include that vartable definition (see line 2014 of cmod_battery, or line 928 if cmod_pvsamv1). I thought it was better to duplicate the lines than include unnecessary variables, but I'm open to other options.

Copy link
Collaborator

@mjprilliman mjprilliman Oct 28, 2021

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

No I like your solution. I was mostly asking for my own understanding


// Powerflow calculation inputs
{ SSC_INPUT, SSC_ARRAY, "fuelcell_power", "Electricity from fuel cell", "kW", "", "FuelCell", "", "", "" },
Expand Down Expand Up @@ -470,8 +473,13 @@ battstor::battstor(var_table& vt, bool setup_model, size_t nrec, double dt_hr, c
ssc_number_t* parr = vt.as_array("om_batt_replacement_cost", &cnt);
if (cnt == 1)
{
double escal = 0.0;
if (vt.is_assigned("om_replacement_cost_escal")) {
escal = vt.as_double("om_replacement_cost_escal");
}

for (i = 0; i < nyears; i++)
replacement_cost[i] = parr[0] * (ssc_number_t)pow((double)(inflation_rate + 1), (double)i);
replacement_cost[i] = parr[0] * (ssc_number_t)pow((double)(inflation_rate + escal + 1), (double)i);
}
else if (cnt < nyears)
{
Expand Down