Transcript T07 Presentation

RESIDENTIAL CHARGING STATION FOR AN
ELECTRIC VEHICLE
RICHARD BROWN & SONIKA NEGI
Second Solar, Inc , A Subsidiary of Kozicki Enterprises
DESIGN TARGET REQUIREMENTS
 Capable of charging an Electric Vehicle - Tesla Model 85 S.
 Independent of the existing residential electrical system and local
electrical grid.
 Able to operate day or night.
 Sufficient storage capacity to provide two days of autonomy.
SYSTEM DESIGN
SYSTEM DESIGN OVERVIEW
 Load Analysis considering EV range and electrical consumption
 Battery selection.
 PV system design based on solar insolation of the location
 Selection of module and its sizing in an array.
 Selection of Charge controllers having MPPT feature.
 Selection of Inverter
LOAD ANALYSIS
 Our target :- Ability to commute 100 miles daily in a Tesla 85S
 Requires 32 kWh daily charge
 Load :- Telsa Model 85S.
http://cdn.teslarati.com
 PV System to be designed for 32 kWh/day
 2 Day Autonomy, requires 64 kWh of battery capacity
BATTERY SELECTION
 Total capacity requirement for 2 days
autonomy = 64 kWh
 Chosen Battery Voltage = 48 V
 Required Battery capacity
 ∴1333.33 Ah @ 48V
 1 VRLA AGM, Outback 1600 RE Battery
 24 individual 2V batteries in series
 Capacity 1378 Ah, at C/20
 For DOD= 50 %, yields life of 1800 cycles
 ~ 5 years life (2 year warranty)
 Total max energy stored - 66.14 kWh.
 Battery round trip efficiency 80%.
Reference:- http://www.outbackpower.com/outbackproducts/store-the-energy
PV SYSTEM DESIGN
 Winter Consideration
 System requirement :- 32 kWh
 Dec (4.9 hr) and Jan (5.1 hr) have least average daily insolation (NREL Data)
 Therefore, Capacity of PV panels= System Req. (32kWh)/ min sun hr (4.9) = 6.53 kW
 Solar Module selected :- Canadian Solar MaxPower CS6X-320 Watt,
Polycrystalline Silicon (72cell)
 Assuming 47.5 Deg C Cell Operating temp. in Paradise Valley, AZ, in Dec and
Jan and temperature coefficient of the module of -0.41 % / °C.
 Resulting power loss of 10.2% in winter. Thus the nominal power=290.5 W/module
 No of modules required = 6.53 kW/290.5 W= 22.5 ; 24 modules considered.
PV SYSTEM DESIGN

Annualized Consideration
 System requirement :- 32 kWh
 Annual Average Daily Insolation of 6.5 hrs (NREL data).
 Therefore, the capacity of PV panels= System Req. (32 kWh)/ avg sun hr (6.5)= 4.92 kW

Winter conditions resulted in system capacity of 6.53 kWh.

Considering 59.5 °C Cell Operating temp as an avg. annualized value and temp. coefficient of
the module of -0.41 % / °C
 Resulting power loss of 14.12 % yearly average. Thus the nominal power=274.82 W/module
 No of modules required = 4.92 kW/274.82 W= 17.90 ; 18 modules.

24 Module Winter requirement is Design Direction resulting in a 7.68 kW PV System.

Additional annual capacity utilized to offset additional system losses.
ARRAY SIZING
The PV system consist of 2 arrays. Each array has 3 parallel strings of 4 modules in series.
Pmax= 320 W, Vmp= 36.8A, Imp= 8.69 A, Voc=45.3 V & Isc=9.26A.
The total voltage of an array is 147.2 V and current is 26.07.
Total power delivered by the PV system = 7.68 kW
SELECTION OF CHARGE CONTROLLER
 Single charge controller with MPPT for each PV array.
 Midnite Solar classic 200 selected
 Efficiency 98%
 Input output characteristic as below:
SELECTION OF INVERTER
 Outback Power GS8048 Radian series grid
hybrid 8kW inverter/charger.
 Nominal DC input voltage = 48 V
 Continuous output power = 8000 VA
 AC output voltage= 120/240 V AC
 Continuous AC output current = 33.33 A
 Efficiency = 93 %
COST BREAKDOWN
S.N
1
Item Description
Canadian Solar Max Power C56X320P (320 Watt modules)
Qty.
(No)
Unit Price
( $)
Total Amount
($)
24
305
7,320
2
Outback 800RE Battery Bank
1
17,798
17,798
3
Midnite Solar Classic 200 MPPT
2
607
1,214
4
Outback Radian GS8048 Inverter
1
4,500
4,500
TOTAL COST OF COMPONENTS
$ 30,842
Total electrical power requirement/day = 32 kWh
As per APS data , cost of per unit consumed = $0.14/kWh
For a day, cost of 32 kWh consumed = $ 4.48
Therefore, electricity savings in an year using stand alone system = $ 1,635.20
FEASIBILITY REPORT
 During winter, 76.3 miles/day range is achieved vs. 100 miles target.
 On annual average basis, 95.8 miles/day range vs. 100 mile target.
 To meet the target of 100 miles/day in winter requires a 33% PV system
capacity increase over the current 7.68 kW proposal, resulting in an overall
system capacity in excess of 10.2 kW.
 The total estimated cost of components = $ 30,842.
 10.2 kW system capacity will increase cost and complexity significantly.
 The PV design for the stand alone EV charging is the optimal design which
can provide a average driving range of 95.8 miles/day on an annualized
basis.
 APS electricity rate is 0.14 $/kWh resulting in an annual electricity savings of
only $1,635 which does not appear to financially justify the investment.
THANK YOU