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Solar Coffee Drying
Throughout Latin America the drying of coffee beans contributes significantly to the destruction of the remaining rain forests. Conventional coffee dryers consume large amounts of wood and electricity to dry the beans after the washing process. In Central America, an estimated 16,086 acres of forest are destroyed to supply the firewood used to dry the coffee production each harvest -- equivalent to over 828,000 barrels of diesel fuel per harvest.
The Solar/Biomass Drying System helps to reduce deforestation by using the sun's energy to dry the harvest.
Because the solar dryers do not need to be connected to the electrical power grid, the drying systems can operate in remote areas, at or near the plantation site. This provides the small grower with the opportunity to dry their own production, greatly increasing the value of their coffee.
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Karnataka, the silicon valley of India, boasts of being 95% electrified. Is it true? In the language of the policy makers, one power line or a "wire" to a single house in a village means that the village is electrified. Furthermore, is it economically worthwhile for the KEB to extend lines into the remote parts of South Karnataka? The average transmission and distribution (T&D) losses in the state of Karnataka are 25%, second only to the hilly states of northeastern India. T&D Losses in addition to the "free" power supply scheme to the pump sector have burdened the state utility with a Rs. 3 billion loss. It is high time the policy makers looked towards other sustainable types of power generation.
India represents perhaps the largest solar market in the world, with a population of 850 million, of which 40% have no electricity. The goal of this study is to develop a model to provide sustainable electricity to rural India. The model is applicable to other countries with similar characteristics.
India has expanded generating capacity from 1,712 Mw in 1950 to 42,000 Mw in 1986 (9% growth per year). Even so, many barriers exist to further grid electrification, particular in rural areas: rough terrain, low power utilization factors, lack of funding. Small, decentralized rural solar photovoltaic systems can overcome some of these problems, but other barriers still exist.
The objective of this study was to design and test envelope, heating, and ventilating systems, which will reduce the reliance on fossil-fuel-based heating technologies in electric vehicles operating in cold climates. To accomplish this, passive solar design and test methods were adapted from buildings to vehicles. Two electric shuttle bus designs were tested over the past two heating seasons in New England. The first bus, a US Electricar 22-foot shuttle bus, is the first battery-powered bus in New England and is owned by the University of Massachusetts Lowell as a shuttle bus both on campus and at Logan Airport. The second bus is an Advanced Vehicle Systems (AVS) 22-foot shuttle bus, owned by the Greater Portland Transportation District, Portland, ME.
The high rate of oil consumption and air pollution problems have stimulated many activities directed toward the development of electric vehicles (EVs). Other than the propulsion system, the climate control system usually consumes more energy than the other accessories in electric vehicles, which, in turn, reduces the vehicle range, particularly in cold weather. For example, GM estimates that the Impact would lose 85% of its range in 0 F weather if no thermal management system were used (GM, 1994). To minimize the loss in range, the energy consumption from the battery must be minimized. The goal of the present work is to develop a thermal storage system using phase-change material (PCM) as a storage medium for EVs. The use of this system has the advantages of negligible use of battery energy, no tailpipe emissions, and less weight than batteries and resistance heaters.
In order to keep zero-emission vehicles in cold climates both warm and truly zero-emission, alternative heating systems must be devised which are not powered by fossil fuels. Heating of electric vehicles presents a considerable challenge if batteries are not to be used as a source of energy in order to keep the vehicle range up. It appears that kerosene heaters are presently used in many electric vehicles in cold climates.
Single junction and multi-junction photovoltaics based on GaAs technology have a number of advantages over silicon-based devices, such as higher efficiency, less sensitivity to atmospheric perturbations and ionizingradiation, and a lower temperature sensitivity coefficient. GaAs photovoltaic use in space programs will increase because it can offer both higher power density and area power density. However, GaAs is not likely to supplant silicon as the mainstay of flat panel photovoltaics, building material photovoltaics, or other cost-driven applications. GaAs cell costs are an order of magnitude higher than silicon and will continue to be higher. In addition, there is considerable difficulty in producing cell sizes larger than several cm2.
While costs are on a downward trend and cell sizes are increasing, the most likely niche application for GaAs-based cells for terrestrial applications is in concentrator arrays for peak load systems. Analysis shows that a module cost of $500/m2 can make a photovoltaic technology competitive for peak load systems as is illustrated in Figure 1. Concentrator modules transfer the costs from high-priced cells to low-priced optics. At cell efficiencies of 25%, concentrator module costs can be brought into the $500/m2 range as is shown in Figure 2. GaAs-based photovoltaic cells have efficiencies that are high enough to offer a concentrator system cost advantage over silicon photovoltaics and viability as a terrestrial power source.
The idea of combining community service and learning is finding acceptance in many schools (Campus Compact Bibliography, 1996). The basic idea is to provide students with experience in community service in a structured manner to apply and/or acquire new knowledge or skills in a course. Matching students with community groups so that learning takes place in specific subject areas so that both the community and the students benefit is not easy, however.