Special Issue 1, December 2009
Article Number: 10
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Study of the technology development of harvesting gravitational potential energy for transportation by using CASWAT-G

L.B. Baral
Pages 57-59

Abstract—What is CASWAT–G? Walking against gravitational pull (ascending) from the foot of hill is difficult. While climbing down from the hill top (descending) controlling one's body against gravitational pull is also difficult. For comfortable walking of both ascending and descending personal, CASWAT-G (Circulating Cable Supported Up-Down Walking Technology by Using Gravitation) arrangement could be a successful technology. In the CASWAT-G technology, the main part- circulating cable circulates between two bull wheels (one fixed to the hill top and the other at its base). The bodies of the ascending (from the hill base) person and descending (from the hill top) person are connected to the circulating cable by connecting cables. The force is equal to (mgsinq)cosd is provided by the descending person to pull the ascending person. Hence, ascending person feels comfortable ascending. By loosing force is equal to (mgsinq)cosd, descending person also feels comfortable descending. This way both ascending and descending personnel can achieve comfortable up-down walking. This technology could be very much useful for hilly country like Nepal for transportation purposes. Tourism also can get enough benefits from it by employing it to rock climbing, trekking and transporting goods. This technology is eco-friendly, cheap and minimum effort is required to make it work. It requires only small walking trail, no need to cut the trees inside the forest trail (even strongly rooted big trees can be used to fit the pulleys if required).
The total force harvested from the descending person = (mgsinq)cosd
If H is the height through which descending person descends then
Total Harvested gravitational potential energy (GPE) = (mgsinq)cosd x H
q = land slop
d = angle made by connecting cable with circulating cable
m = mass of descending person
g = acceleration due to gravity
Calculation showed, about 66 % of weight (i.e. 32.8 kg) of descending person can be harvested to pull up the ascending person for q = 45º, d = 20º, m = 50 kg.

Keywords—CASWAT-G, gravitational potential energy.