The following variables are calculated during
the
simulation process, and available as results:
Meteo and irradiation variables: see previous page.
PV array behaviour
| EArrMPP
|
Array virtual energy at MPP
(after wiring, module quality and mismatch losses), |
Virtual calculation independent
of the system running and voltage operation
| EArUfix
|
Array virtual energy at fixed voltage |
Voltage as calculated by the
balance loop (real battery voltage),
or Battery reference
voltage when PV-array disconnected.
| EUnused
|
Unused energy (full battery) loss
(EArUFix when Charging OFF) |
| MPPLoss
|
Loss with respect to the MPP
operation (when charging ON) |
| Earray
|
Effective energy at the output of
the array (when charging ON) |
| IArray
|
Array Current
(accumulated in Ah) |
| UArray
|
Array Voltage
(average when Charging ON) |
| ArrayON
|
State / Duration of the PV
production of the array |
If converter present: converter losses
| CL Oper
|
Converter loss during operation
(efficiency curve) |
| CL Pmin
|
Converter Loss due to power
threshold' |
| CL Pmax
|
Converter Loss due to power
overcharging |
| CL Vmin
|
Converter Loss due to low voltage
MPP window |
| CL Vmax
|
Converter Loss due to upper
voltage MPP window |
| CnvLoss
|
Global converter losses |
| OutConv
|
Energy at converter output
|
Battery
operation: storage, losses and ageing
| EBatCh
|
Battery Charging Energy
|
| U Batt
|
Average battery voltage,
any conditions, |
| UBatCh
|
Battery Voltage during charging
operation |
| IBatCh
|
Battery Charging Current
(all currents accumulated [Ah]) |
| ChargON
|
Charging duration |
| EBatDis
|
Battery Discharging Energy
|
| UbatDis
|
Battery Voltage during discharge
operation |
| IBatDis
|
Battery Discharging Current
(all currents accumulated
[Ah]) |
| DischON
|
Discharging duration |
| ESOCBal
|
Stored energy balance
(according to SOCEnd - SOCBeg) |
| SOCmean
|
Average State of Charge during
the period |
| SOC Beg
|
State of Charge at beginning of
time interval' |
| SOC End
|
State of Charge at end of time
interval' |
| NB:
|
The SOC current calculations are referred to
the actual capacity of the
battery, which is defined at nominal current, but varies with the
discharge current level and temperature. Therefore it is not quite
well determined, and not reversible (i.e. it can be different when
charging and discharging). |
| EBatLss
|
Battery global energy loss
(EBatCh - EBatDis - ESOCBal) |
| IBEffL
|
Battery charge/discharge current loss
(coulombic
efficiency [Ah]) |
| IBGass
|
Gassing Current loss
(electrolyte dissociation
[Ah]) |
| IBSelf
|
Battery Self-discharge Current
(depends on
temperature [Ah]) |
| EBattEff
|
Battery energy efficiency
(IBEffL * U
Batt) |
| EBGass
|
Gassing Current energy loss
(IBGass * U
Batt) |
| EBSelf
|
Battery Self-discharge Energy
(IBSelf *
U Batt) |
| NB:
|
The
sum of the detailed battery losses contributions appearing on the
loss diagram should in principle match this Battery Global Energy
Loss calculated above, i.e:
|
|
|
EBattLss =
EBattEff + EBSelf + EBGass
|
|
|
But
during the simulation, all these contributions are determined from
the Currents balance of the system (PV array - Battery -
Load), multiplied by the Battery Voltage, which is varying with
currents, charge/discharge state, state of charge, temperature,
etc. The resulting energies are therefore defined with some
uncertainties.
|
|
|
On
the other hand, as explained above, the ESOCBal is also not well
determined.
|
|
|
Therefore the overall energy balance on the
battery cannot be quite rigorous.
|
| WeCycle
|
Wearing due to cycling
|
| WeState
|
Wearing state (cycling and age)
|
| MGass
|
Dissociated Electrolyte Mass per cell
|
System
operating conditions
| E BkUp
|
Back-up Generator
Energy (UBatt * I BkUp) |
| I BkUp
|
Back-up Generator Current'
(accumulated in
Ah) |
| BkUp ON
|
Back-up Generator running duration
|
| FuelBU
|
Fuel consumption of Back-up Generator
|
Energy use
| E Avail
|
Available Solar Energy
Energy at the output of the array when producing
- converter loss + Unused energy |
|
|
E Avail = E Array - CnvLoss + E Unused
|
| E Load
|
Energy need of the user
(Load) Defined as Input data |
| E User
|
Energy supplied to the
user
Including back-up
energy |
| SolFrac
|
Solar fraction
(EUser -
EBkUp) / ELoad |
When no back-up generator
defined
| E Miss
|
Missing energy
Eload - Euser |
| SolFrac
|
Solar fraction
EUser /
ELoad |
| T LOL
|
Duration of "Loss of Load"
Duration
user not supplied |
| Pr LOL
|
Probability of "Loss of Load"
Idem as percentage of time
|
Efficiencies
| EffArrR
|
Array Efficiency:
EArray / rough area |
| EffArrC
|
Array Efficiency:
EArray / cells area
(=0 when
cells area not defined) |
| EffSysR
|
System efficiency
E User / rough area |
| EffSysC
|
System efficiency
E User / cells area
(=0 when
cells area not defined) |
| EffBatI
|
Battery current charge/discharge
efficiency
|
| EffBatE
|
Battery energy charge/discharge efficiency
|
Normalised performance index
| Yr
|
Reference Incident Energy in
collector plane = GlobInc
[kWh/m²/day] |
| Yu
|
Normalized Potential PV
Production (battery never full)
[kWh/kWp/day] |
| Ya
|
Normalized Array Production
= EArray
[kWh/kWp/day] |
| Yf
|
Normalized System Production
= EAvail
[kWh/kWp/day] |
| Pr
|
Performance ratio
= Yf / Yr. |
| Lu
|
Normalized Unused energy
= Yr - Yu |
| Lc
|
Normalized Array Losses
= Yu - Ya |
| Ls
|
Normalized System Losses
= Ya - Yf |
| Lur
|
Unused (full battery) Loss / Inc.
Energy Ratio = Lu / Yr |
| Lcr
|
Array Loss / Incident Energy
Ratio = Lc /
Yr |
| Lsr
|
System Loss / Incident Energy
Ratio = Ls /
Yr |
