HIGH ALTITUDE AIRSHIP

Literature Review

• HALE-D HAA:1. Hull Vol: 50 000ft^3=>3,700,000ft^32. Length : 240ft=>500ft3. Diameter: 70ft=>150ft4. Propulsion motors:2 Kw Electric5. Energy storage:40Kwh(Li-ion battery)6. Solar Array:15Kw thin film7. Station keeping altitude:60,000ft8. Payload Weight:50lbs(23Kg)9. Payload Power:10. Life time>15days(Trail Target:90 days)11. Reusable :Yes

FULL SCALE HAA

• With subsequent work being carried out the full scale HAA is expected to function at quasi geo-synchronous orbit for a period of 10 years.

• The Airship operates in the stratosphere just barely within the outer limits of the earth's atmosphere.

• The geostationary position of 60,000 -70,000feet (18-21 km) has been selected because there are minimal wind conditions during a significant part of the year at this altitude and the air density is only five percent of that at the surface.

PARAMETER FINALISATION

• Parameters to be finalised:PV Panel1. PV panel area2. PV panel weightBattery Weight(Saft VL 6Ah Lithium-ion

battery)URFC(Unitized Regenerative Fuel Cell)

PV Panel Area Calculation• On ground: Power Area 1KW unit - 8m-sq 30KW unit - 240m-sq 40KW unit - 320m-sq• Solar flux increases significantly as we move to higher altitudes in earth’s

atmosphere.• At at height of 60,000ft(18,000m): Power Area 0.03W unit - 1cm-sq 3KW unit - 1m-sq 40KW unit - 13.34m-sq 50KW unit - 16.67m-sq With increased in altitude and use of thin film solar cell technology area of solar panel required for a particular amount of power requirement can be significantly reduced.

Calculation : Weight of PV panel

• Data from specification sheet of a solar module(Data for solar panel used):

1. Dimension:306mm X 218mm X 25mm2. Power=5Kw3. Weight=1.00KgVol. of solar panel=(306X218X25)/10^9 m^3Density for a normal traditional solar panel=1/vol=599.628Kg/m^3

Calculation : Weight of PV panel

• Range of thickness of thin film solar cell varies from few nanometers to few micrometers i.e in the orders of 10^(-9) to 10^(-6) much less than 25mm thickness in traditional PV panels.

• Normal PV density=599.628Kg/m^3• Area of solar panel(to be used at

60000ft(=18Km):13.34m^2(16m^2)Considering the thickness of the thin film to be

maximum in orders of 10^-6(micrometers).Vol of solar panel:7.99 X 10^-3Kg(9.5 X 10^-3Kg)

Battery Weight Calculation

• Battery: Saft VL 6Ah Lithium-ion battery• Operating temp:25 degree Celcius• Power to weight ratio: 21370 W/kg • Rating:40Kw• Weight=(40000/21370)Kg=1.8kg

Operational Requirements for a 20Kw RFC

• O/P Pow=20KW• Duration of discharge mode=1.25hrs• Required storage of energy=25KWh• Cycle efficiency=58%• Available time for charging=22.5h• I/P Pow during charging=1.9KW• Min. operational lifetime=15yrs• Total no. of charging cycles=1300

Operational Requirements for a 20Kw RFC

• Total time in discharge mode=1300h• Total time in charge mode=23000h• Required quantity of hydrogen=1.18Kg• Required qty. of oxygen=9.36Kg• Hydrogen flow in discharge mode=7.8mol/min• Oxygen flow in discharge mode=3.9mol/min• Hydrogen flow in charge mode=0.43mol/min• Oxygen flow in charge mode=0.22mol/min

CONDITIONING CIRCUIT REQUIREMENT?

• A power conditioner (also known as a line conditioner or power line conditioner) is a device intended to improve the quality of the power that is delivered to electrical load equipment.

• The term most often refers to a device that acts in one or more ways to deliver a voltage of the proper level and characteristics to enable load equipment to function properly.

SOLAR PANELWorking Principle : Thin Film Solar Cell

Advantages of Thin Film Solar Cell over standard Solar Cells

• 1) Saves material and reduces the weight of Air Ship,which is a major factor for airship performance.

• 2) Compare to traditional PV Cells ,thin film solar cell can produce more amount of electrical power with the same amount of area as they are based on mono crystalline .

• 3) Cheaper than traditional panels• 4) Easy to handle • 5) More flexible than conventional solar cells• 6) Available as thin wafer sheets

Overall Specifications

• Total Power Rating: 40KW• Area of PV panel : 13.34m-sq• o/p pow(URFC): 40KW• Operational lifetime: 10-15yrs ( with maintenance)• Solar module o/p energy density:3KW/m-sq• Payload Capacity:135lbs(63Kg)

CONCLUSION

• The parameters calculated for modeling of solar powered airship seem to be in agreement with one another.

• The total weight of the model is well below the payload capacity .

i.e Weight(Battery+URFC+Solar Panels +Conditioning Ckt.) < (Payload Capacity(135lb))