Design & Selection...SOLAR + BATTERY DESIGN 9. SELECTING, SIZING & PROGRAMMING INVERTERS Power...

DESIGN & SELECTION

OFF-GRID BATTERIES

Txt me your questions: Glen Morris 0419 299 140

SMART ENERGY COUNCILBATTERYSURVEYMay 2017

WORKPLACE HEALTH & SAFETY

SOLAR + BATTERY DESIGN

1. WORKPLACE HEALTH & SAFETY

▸Solar PV high d.c. voltages

▸ELV battery high short-circuit currents

▸LV battery high d.c. voltages similar to a PV array

▸Explosive gases (hydrogen + oxygen from PbA)

▸Chemical hazards (ie. acid spillage)

▸Fire hazard (self-ignition possible with lithium batteries)


BATTERIES ARE HEAVY▸ use appropriate lifting and moving

equipment

▸ ensure structural integrity of mounting

surface

▸ hazardous good regulations may

effect transport options

▸ use insulated tools on exposed

terminals

SYSTEM CONFIGURATIONS


2. SYSTEM CONFIGURATIONS

▸A.C. Coupled

▸D.C. Coupled

▸Single grid-port

▸Multi-port (grid and stand-alone)

▸D.C. - d.c. converter

▸ “AC Battery” (ie. Enphase & Powerwall 2)



A.C. COUPLE SYSTEMS

Pro’s

▸easy to retrofit storage

▸ scales easily

▸no co-location with solar

▸ simple to install

▸ suits daytime energy use

Con’s

▸may not provide backup

▸adds to IES capacity

▸no solar charge when grid

down

▸energy meter required


BATTERY CHARACTERISTICS


3. BATTERY CHARACTERISTICS

▸Cell v’s battery v’s BESS

▸Discharge rate (kW or A)

▸Charge rate (kW or A)

▸Amp-hour or Watt-hour capacity

▸State of Charge (SOC)

▸Depth of Discharge (DOD)


3. BATTERY CHARACTERISTICS

▸Nominal voltage

▸Cutoff voltage

▸Absorb (or Boost) voltage

▸Float voltage

▸Self discharge rate

▸Design life (years or cycles)


VOLTAGE DROOP WITH DEPTH OF DISCHARGE


C RATES FOR BATTERIES


VRLA SONNENSCHEIN (LEAD-ACID)


VRLA CYCLE LIFE (SONNENSCHEIN A600)


CAPACITY VS DISCHARGE RATE (SONNENSCHEIN A600)

BATTERY TECHNOLOGIES


4. BATTERY TECHNOLOGIES

▸Lead-Acid (VRLA v’s flooded)

▸Lead-Carbon

▸Lithium ion (LiFePO4, NMC, NCA, LTO etc…)

▸Flow battery (Vanadium Redox & Zinc Bromine)

▸Hybrid ion (Aquion)

▸Hybrid Supercapacitors (Kilowatt Labs)

▸Nickel alkaline (NiCd)

▸Molten salt battery (Na-NiCl2 & NaS)


COMPARISON OF LITHIUM ION BATTERY CHEMISTRIES

SELECTING & SIZING SPECIFIC LOADS


5. SELECTING & SIZING SPECIFIC LOADS

▸Customer load energy requirement

▸Customer maximum power demand

▸Period of autonomy (if any)

▸PV supplied v’s battery supplied energy

▸ Inverter power rating

▸Self-use v’s Peak lopping v’s Backup


BEST RESEARCH-CELL EFFICIENCIES

SELECTING & SIZING BATTERY


6. SELECTING & SIZING BATTERY

▸Daily load energy required

▸Battery system voltage

▸Load sub-system efficiency

▸Amp-hour demand

(typically daily except if blackout protection)

▸Days of Autonomy (≥1day if off-grid)

▸Amp-hour capacity required @ Cx


BATTERY SIZING EQUATIONS

▸A - daily load energy (Wh)

▸B - battery system voltage (V)

▸C - load sub-system efficiency (0.xx)(wiring, battery round-trip, and inverter efficiency)

▸D - Amp-hour demand = A ÷ B ÷ C

▸E - Amp-hour capacity = (D x DoA) ÷ DoD max.NB. to convert to kWh = (Ah x V) ÷ 1000


BATTERY SIZING WORKED EXAMPLE

▸A - daily load energy 10,000Wh

▸B - battery system 48V

▸C - load sub-system efficiency 0.74

▸D - Amp-hour demand = 10,000 ÷ 48 ÷ 0.74

= 282Ah

▸E - Amp-hour capacity = (282 x 1) ÷ 0.9

= 313Ah @C10

= 313 x 48 = 15kWh (total capacity)

SIZING THE PV ARRAY


7. SIZING THE PV ARRAY

▸Daily load energy requirement

▸Peak Sun Hours (PSH) of site

▸Derating for shade

▸PV sub-system efficiency

▸Load sub-system efficiency

SOLAR CHARGE CONTROLLERS


8. SOLAR CHARGE CONTROLLERS

▸D.C. Coupled

▸A.C. Coupled

▸Micro-inverters

▸PV String considerations

▸Co-location v’s distributed location

▸ELV v’s LV d.c. charge controllers

▸Combo d.c. + a.c. (aka “Black Start”)

SELECTING, SIZING & PROGRAMMING INVERTERS


9. SELECTING, SIZING & PROGRAMMING INVERTERS

▸Power ratings (continuous, short term, surge)

▸Battery system voltage (12/24/48/120/300+)

▸Temperature derating

▸Grid/Generator support

▸AC pass-through current

▸Software feature sets

SYSTEM WIRING


10. SYSTEM WIRING

▸Maximum inverter current

▸Maximum charge controller current

▸D.C. loads or a.c. only

▸Cable selection (maximum CCC)

▸Ripple factor (worse with 1∅ or unbalanced 3∅)

▸Overcurrent protection selection

SYSTEM EFFICIENCY & PV/BATTERY YIELD


11. SYSTEM EFFICIENCY & PV/BATTERY YIELD

▸PV to load efficiency

▸PV to battery efficiency

▸Battery to load efficiency

▸Grid to battery efficiency (and cost)

▸Levelised Cost of Electricity (Cost/Energy)

SYSTEM PHYSICAL LAYOUT


12. SYSTEM PHYSICAL LAYOUT

▸Co-location

▸Manufacturer’s minimum clearances

▸Australian Standards requirements

▸Ambient thermal load + emitted heat

DOCUMENTATION & SIGNAGE


13. DOCUMENTATION & SIGNAGE

▸AS/NZS 5033 requirements

▸AS/NZS 5139 requirements

▸AS/NZS 4777.1 requirements

▸Shutdown procedure

▸Location of signage

▸Electrical system schematics and equipment location plans

Design & Selection...SOLAR + BATTERY DESIGN 9. SELECTING, SIZING & PROGRAMMING INVERTERS Power...

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