870 resultados para Heat Solar Energy
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Item 231-B-1
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Edited by A. S. Hundemann.
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Mode of access: Internet.
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"NBSIR 76-1562."
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Description based on: Fiscal year 1986.
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"No. 139."
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"March 1983."
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"June 1980."
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On cover : Shawnee Solar Project.
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Caption title.
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"Literature cited": p. 95-103.
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Published by the Solar Energy Research Institute, a division of Midwest Research Institute, for the United States Department of Energy under contract no.EG-77-C-01-44042
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A need was indicated for the identification of a possible new solar energy product to improve the sales potential of a metal film with a selective surface, manufactured by the industriaI sponsor of this project (INCO). A possible way of overcoming the disadvantageous economics of solar energy collection was identified. This utilised the collection of solar energy by the walls of buildings constructed in such a manner as to allow the transfer of energy into the building, whilst providing adequate thermal insulation in the absence of sunlight. The actual collection element of the wall, being metallic, is also capable of performing the function of a low temperature heating .system in the absence of sunlight. As a result of this, the proposed system, by displacing both the wall and centraI heating system which would otherwise be necessary, demonstrates economic benefits over systems which are constructed solely for the purpose of collecting solar energy. The necessary thermodynamic and meteorological. characteristics and data: are established, and applied to a typical urban site in the North of England, for a typical average year, with and without a shading device incorporated into the construction. It is concluded that the proposed system may offer considerable benefit in reducing the effective heating season in all orientations of wall.
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The aim of this paper is to identify and evaluate potential areas of technical improvement to solar-powered desalination systems that use reverse osmosis (RO). We compare ideal with real specific energy consumption (SEC) to pinpoint the causes of inefficiency. The ideal SEC is compared among different configurations including a batch system driven by a piston, and continuous systems with single or multiple stages with or without energy recovery in each case. For example, to desalinate 1 m3 of freshwater from normal seawater (osmotic pressure 27 bar) will require at least 0.94 kWh of solar energy; thus in a sunny coastal location, up to 1850 m3 of water per year per m2 (m3/m2) of land covered by solar collectors could theoretically be desalinated. For brackish water (osmotic pressure 3 bar), 11570 m3/m2 of fresh water could theoretically be obtained under the same conditions. These ideal values are compared with practically achieved values reported in the literature. The practical energy consumption is found to be typically 40-200 times higher depending on feed water composition, system configuration and energy recovery. For state-of-the-art systems, energy losses at the various steps in the conversion process are quantified and presented with the help of Sankey diagrams. Improvements that could reduce the losses are discussed. Consequently, recommendations for areas of R&D are highlighted with particular reference to emerging technologies. It is concluded that there is considerable scope to improve the efficiency of solar-powered RO system.
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Purpose: Energy security is a major concern for India and many rural areas remain un-electrified. Thus, innovations in sustainable technologies to provide energy services are required. Biomass and solar energy in particular are resources that are widely available and underutilised in India. This paper aims to provide an overview of a methodology that was developed for designing and assessing the feasibility of a hybrid solar-biomass power plant in Gujarat. Design/methodology/approach: The methodology described is a combination of engineering and business management studies used to evaluate and design solar thermal collectors for specific applications and locations. For the scenario of a hybrid plant, the methodology involved: the analytical hierarchy process, for solar thermal technology selection; a cost-exergy approach, for design optimisation; quality function deployment, for designing and evaluating a novel collector - termed the elevation linear Fresnel reflector (ELFR); and case study simulations, for analysing alternative hybrid plant configurations. Findings: The paper recommended that for a hybrid plant in Gujarat, a linear Fresnel reflector of 14,000 m2 aperture is integrated with a 3 tonne per hour biomass boiler, generating 815 MWh per annum of electricity for nearby villages and 12,450 tonnes of ice per annum for local fisheries and food industries. However, at the expense of a 0.3 ¢/kWh increase in levelised energy costs, the ELFR can increase savings of biomass (100 t/a) and land (9 ha/a). Research limitations/implications: The research reviewed in this paper is primarily theoretical and further work will need to be undertaken to specify plant details such as piping layout, pump sizing and structure, and assess plant performance during real operational conditions. Originality/value: The paper considers the methodology adopted proved to be a powerful tool for integrating technology selection, optimisation, design and evaluation and promotes interdisciplinary methods for improving sustainable engineering design and energy management. © Emerald Group Publishing Limited.