Current status of the traditional watermills of the Himalayan region and the need of technical improvements for increasing their energy efficiency

Traditional watermills of the Himalayan region are centuries old water-power driven small-scale industry which is serving mountain inhabitants till date. But, day by day it is becoming tough for this eco-friendly technology to keep pace with modern technologies; hence its future is dubious now. Various organizations throughout the world are trying to rejuvenate and re-popularize this environment-friendly technology for multipurpose use. However, instead of improving its existing design, stress is being given to increase the adoptability of new-design watermill. In spite of all efforts, the new-design watermill has not shown any sharp impact on its adoptability rate. Certainly, there are issues which are not considered while implementing line of action. Before commencing the study, thorough discussions on the issues affecting the watermills’ existence in the region were made with the remotely residing watermill owners. Complete study is divided into two parts. In the first part, the issues that are deciding the fate of watermills’ existence in the region are discussed. Keeping all discussed-issues in mind, design of various components of an in-operation watermill is reviewed and modifications are proposed for increasing its efficiency. For the purpose, analytical expressions for evaluating watermill efficiency are also derived.

► Analytical solutions for evaluating the traditional-watermill’s efficiency are derived. ► Blade surface modification from flat to circular-paraboloid increases efficiency by 7.51%. ► Water-jet angle alters the geometric dimensions of the blade due to abrasion. ► Replacement of chute with circular pipe increases the power generation by 0.366 kW.