Proposal For Installation Of Solar PV Power System And Steam

Cooking System

BySRIDHAR S.I

B.Tech Energy and Environmental Engineering

Place : University Canteen.

Location: Tamil Nadu Agricultural University.

Coimbatore 3.

Consumption Pattern:• Minimum Consumption – 25units / day.

• Average Consumption – 27units / day.

• Maximum Consumption – 30units/ day. (exceptional)

Objective:To design Solar PV system for average consumption.(i.e., 27units /day).

Solar Hybrid – Grid tie with solar.

The PCU draws current from the grid, when the power from the battery is not sufficient to run the appliances.

Load & Consumption:

Appliances Nos. Rated Load Working Hrs Consumption (Wh)

Fan 05 70W 10hrs 3500

Tube Light 08 60W 07hrs 3360

Fan 05 70W 02hrs 700

Tube Light 08 60W 02hrs 960

KITCHEN

Tube Light 04 60W 16hrs 3840

Coffee Machine 01 1500W 01hrs 1500

Refrigerator 02 375W 24 (12hrs) 9000

Pump 01 746W 45min 560

Wet Grinder 02 746W 1.5hrs 2238

Wet Grinder 02 373W 01hrs 746

Tube Light 02 60W 06hrs 720

TOTAL 27124Wh

Condition:

Consider any one usage at a time among Coffee Machine,

pump, & Wet Grinder.

Appliances Consumption (Wh)

Fan 3500

Tube Light 3360

Fan 700

Tube Light 960

Tube Light 3840

Wet Grinder 2238

Wet Grinder 746

Refrigerator 9000

TOTAL 25064Wh

Panel Selection:

Total Consumption - 25064Wh

Additional 30% watt loss per day for loss calculation – 7519.2Wh

Total capacity of SPV system req. – 32583.2Wh

Assuming Avg. 5hrs sunlight per day

SPV module capacity req. – 6516.64W

~ 6520W( app ).

Select,

• 250Wp (12V) panel in 26 nos. (6520/250 = 26).

Battery sizing:

Consumption

= -------------------------------------------------

Battery Efficiency * DOD* 12V

= 25064/ 0.85*0.6*12

= 4095Ah

= 4100Ah (app)

Select,

350Ah Batteries in 12 nos. ( 4095/350= 11.7).

PCU Selection:

Appliances Nos. Watts Multi. factor Rated Load

Fan 05 70W 1.2 420

Tube Light 08 60W 1.2 576

Fan 05 70W 1.2 420

Tube Light 12 60W 1.2 864

Refrigerator 02 375W 03 2250

Wet Grinder 02 746W 03 4476

Wet Grinder 02 373W 03 2238

TOTAL 11244VA

Req. PCU Size is for 11.2KVA.

Select PCU for 12KVA (app).

Wiring Pattern:

Total 26 panels each of 250Wp (12V).

13 panels in series (13*12 = 156V) – 1String.

13 panels in series (13*12 = 156V) – 2string.

Connect string1 & string2 in parallel.

The net voltage is 156V.

Total 13 Batteries each of 350Ah (12V).

Connecting 13batteries in series = 156V.

PCU for 12KVA , 156V.

Cost Estimation:

Items Nos. Amount

SPV array (250Wp, 12V) 26 Rs.325000 ( @ Rs 50/W)

Battery (350Ah, 12V) 13 Rs.420000

Inverter (12KVA, 156V) 01 Rs.225000

• Mounting Structure – Rs.65000 ( @ Rs.10/W).

• Installation cost - Rs.32500 ( @ Rs.5000/1KW).

• Total cost - Rs.1067500.

30% MNRE subsidy,

Net Investment – Rs.747250 ( 7.5 Lac app).

Net Savings:

Units consumed – 27 units / day (app).

810 units / month.

Per unit costs – Rs.5 (commercial usage).

Rs.4050 / month.

Rs.48600/ annum.

This amount can be saved per annum in EB bill.

CER Estimation:

1 CER = 1 ton of carbon-dioxide saved.

Units saved / month – 850 units.

Units saved / year – 10200 units.

Therefore,

10.2 CER saved per year

Recommendation:

Replace all FL lamps with CFL / LED lamps.

Avoid using all heavy loads appliances at a time.

The we can reduce the consumption and subsequently the cost for

solar PV system can also be reduced.

Solar Steam Cooking System

Consumption:

5 – 6 LPG cylinders / day.

A boiler of capacity 300 liter ( wood fueled boiler).

Objective:

To replace the wood fueled steam boiler with solar steam cooking

system.

Boiler Details:

Capacity – 300 liters.( 4 chamber- 100kg of rice can be cooked).

Steam pressure – 1.5bar.

Temperature of the steam - 120°C.

Boiler radius, r = 35.8cm

Boiler area ( pot area) = 0.4sq.m

Energy Required For The Boiler:

Q = mass of water * heat capacity of water (final temp – ambient temp)

therefore,

Q = 300 * 4.18 * (120ºC - 30ºC)

= 112860KJ.

Since, boiler is 70% efficiency ( 30% loss)

= 112860000 * 0.3

= 33858000J.

Therefore, total heat energy req.

Q =112860000 + 33858000

= 146718000J = 146718KJ.

Collector Plate Sizing:

Boiler area (pot area) = 0.4sq.m

• Collector plate available in India (7, 9, 9.2, 10, ….16sq.m).

Choose 10sqm collector plate.

• Concentration ratio =10/0.4

= 25.

Therefore,

density of solar radiation at the focus point

= concentration ratio * direct radiation * efficiency of collector

= 25 * 500W/sq.m * 0.75

= 9375 W/sq.m.

Actual solar radiation at the boiler area,

= density of radiation * focus point area.

= 9375 * 0.4

= 3844 watts

Therefore,

actual available wattage at the focus point of a10sq.m collector plate,

= 3844watts.(3844 J/S).

7 * 3844 = 26908watts.

Select 7 collector plate of each 10sq.m

Time required to cook the food = req.energy / (available wattage * 3600)

= 146718000 / (26908 * 3600)

= 1.5hrs.

Cost Estimation:

Cost of a collector plate with aperture diameter 1.4m – Rs.6000

so a 10sq.m( dia 3.6m) collector plate cost is – Rs.15500 .

Therefore, cost of 7 plates = Rs.15500 * 7

= Rs. 108500.

Pay Back:

Cost of wood per day = Rs.90 ( to produce 146718KJ Heat energy).

Cost per annum = Rs.32400.

Pay back period = 108500 / 32400.

~ 3 years.

THANK YOU