Solar & Wind Technology最新文献

In 1984 Kelp Industries converted a seaweed drying kiln from oil to wood firing. Annual oil cost savings of over $100,000 are now being achieved. Based on detailed resource assessment, and a 15 year contract of sale, wood supply to the company is assured. Retention of money in the island economy has had a community benefit, viability of logging operations has been improved, and Kelp Industries are now more internationally competitive.

In the present work we have produced polycrystalline n-CdTe film on Cd element as substrate by direct surface reaction between elemental Te and Cd surfaces, at elevated temperatures ranging between 180 and 275°C under argon atmosphere. The film is characterized by X-ray diffraction and reflectance spectroscopy. The i-V characteristics and photoelectrochemical behaviour of CdTe in polysulphide electrolyte are investigated. The effect of light intensity on both short circuit current (i_sc) and open circuit voltage (V_oc) of the cell: Cd/CdTe/polysulphide/Pt is also recorded.

Economic optimization procedure in particular solar heating design is based on the estimation of the size of a solar system in terms of collector area that will yield the highest total saving produced on behalf of the solar system in comparison with the total expenditures of a conventional alternative during the life-cycle. The most influential design parameter in a total saving is considered to be the collector area. A case study is then realized so as to find the optimum collector area for maximum saving. Saving function for a particular system is defined. Optimum collector area is considered to be the one which makes zero the first derivative of saying function with respect to the collector area. To this end three different methods, namely, Newton's, Secant and Regular falsi are applied for a variety of changes in values for design, climatic and economic parameters. Finally, the ability to use these methods are discussed from the computational point of view.

The paper is an account of personal experience encouraging and installing appropriate technologies in Indonesia and Africa. Examples are given of local incentives and barriers to change. The social implications of new and changing technologies are of the greatest importance.

With the exception of a three year record of diffuse insolation over Quetta, diffuse and direct insolation is not recorded at any location in Pakistan. The empirical relation due to Mani and Chacko (Solar Energy14, 139, 1973) for diffuse insolation has therefore been applied to estimate diffuse insolation over 37 locations in Pakistan and three neighbouring stations. Direct insolation is also obtained for the same locations. Using the data for 40 locations, diffuse and direct insolation is presented on maps. The isolines are compared with the results obtained for India and world maps.

This paper establishes a standardization procedure in which results are presented in ready-to-use charts for the economic evaluation of biogas plants. It is hoped this work will alleviate controversial reports on cost-effectiveness of biogas systems. Also, it is found that these systems are the most economic among renewable energy systems using a standardized procedure for their comparison augmented by the generated spider diagrams wherein most probable costing production values for each system are directly compared.

A long term research programme investigating the production, processing and utilization of triglyceride oils/fats as diesel fuel substitutes has recently been completed. Vegetable oils and animal fats when converted into esters have been conclusively shown to be technically suitable for use as fuels for compression ignition engines. They can be blended with diesel fuel at any level or used neat. Conversion into esters is a simple chemical process which can be carried out on a small or large scale. Current values of crude oil at around US$20/barrel make it an uneconomic proposition to produce and process vegetable oils for fuel purposes. In the longer term if and when oil prices rise again, the use of vegetable oil fuels may become an economically viable option. In the meantime research programmes continue in countries aiming to utilize surplus rural land and in those wishing to become independent of unreliable oil product imports.