Page 301 - Handbook of Energy Engineering Calculations

downward gravity force due to the weight of the kite and its string. Another
possibility is to tie a balloon to the kite.
A detailed theoretical analysis of the proposed scheme has been carried
out. This analysis indicates that the proposed scheme is scalable, that the drag
on the kite string is small in comparison to the pull in the string for large

devices, and that approximately 0.38 kW of power theoretically can be
2
2
obtained from a kite 1.2 yd (1 m ) in area. In addition, there are no material
or system constraints which will prevent the kite from achieving an elevation
of 5000 ft (1500 m).
Even though it is difficult to estimate the cost of wind power from the
proposed scheme, a rough estimate indicates that for a 100-kW system, the
capital cost per unit of energy from the proposed scheme will be less—

approximately by a factor of 3—in comparison with the capital cost of one
unit of energy produced from other 100-kW wind-energy systems.
The most important application of kite-based energy systems is in
developing countries where these systems can be used to pump water from

wells, grind grain, and generate electricity. A majority of developing
countries do not have an adequate supply of indigenous oil and gas, nor can
they afford to buy substantial quantities of fossil fuel at international prices.
What these countries prefer is a system that could generate useful energy by

using as inputs resources that are available within the country. The simple
scheme proposed here is ideally suited for the needs of developing countries.
The kite-based system may also be economically attractive in comparison
to a small windmill of less than 1 hp (750 W) which has been used in rural

and farm areas in the western United States to pump water, generate
electricity, and irrigate land. Another application of the proposed scheme is to
generate auxiliary power in large sailboats, motorboats, and ships where
conventional wind-energy schemes cannot be employed. The wind-energy

system employing kites can also be used as a fuel saver in conjunction with
already existing transmission lines.
A kite flying at an altitude of 5000 ft (1500 m) may present a hazard to
low-flying airplanes. One way to avoid a collision with the kite or an

entanglement with the kite lines is to enhance their visibility by providing
flashing lights around the kite structure and along its retaining line. Another
approach is to fly the kites at lower altitudes. For instance, even at an altitude