共查询到20条相似文献,搜索用时 46 毫秒
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全玻璃真空管太阳空气集热器的应用李曾豫殷志强刘学臣太阳空气集热器是以空气为热载体的太阳集热器,其品种繁多,性能、结构各异,在采暖、干燥、空调、温室种植、食品加工等领域具有广泛的潜在应用前景.其中,从经济与效益着眼,全玻璃真空管太阳空气集热器是比较理想... 相似文献
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随着人们节能和环保意识的增强,太阳热水系统已逐渐进入千家万户。有关资料表明,我国目前已经成为世界上使用太阳热水器数量最多的国家。然而,现在广泛采用的太阳热水系统,大部分是太阳集热器直接加热的单回路热水系统。该系统虽然使用方便,但对于高寒地区冬季系统防... 相似文献
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一、前 言 我国大部分山区都有生产香菇的传统.随着农村经济的发展和人民生活水平的提高,香菇的消费量愈来愈大.此外,国际市场对香菇的需求量也日趋增加.因此近几年来,我国许多山区和农村积极发展人工培育香菇,有些贫困山区把发展香菇作为脱贫致富的有效途径.但是长期以来,农村传统的香菇干燥工艺都是将鲜菇装在篦筐里,架在火盆上用炭火烘为干菇。这种烘干方法存在着三大问题,一是由于火盆里的炭火燃烧温度无法控制,只能凭经验操作,火力分布不均,干燥出来的干菇含水量不匀,往往出现局部烘焦,达不到出口的标准;二是这种低档次的烘干,不仅需要消耗大量的木炭和木柴,人工添火翻动操作,劳动强度大;三是由于鲜菇含水量高达900%(干基)以上,24小时内不烘干就要变质腐烂.现在山区大面积发展香菇,有 相似文献
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总结和推导了常用太阳空气集热器的有用得热的数学表达式,分析了UL,F‘,FR的数学表达式与热水器的异同,指出了测试和设计空气集热器时应注意的有关问题。 相似文献
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A natural extension of the design procedure for liquid-based solar space and water heating systems is a similar analysis for solar heating systems using air as the heat transfer fluid. In this paper, a solar air heating system incorporating a flat-plate air heater and packed bed thermal storage is described and a simulation model for the system is developed. The results of many simulations of the air heating system are used to establish the relationship between system performance and the system design and meteorological variables. The results are presented in analytic and graphical form, referred to as an f-chart for solar air heating systems. The results of simulations in several widely different climates suggest that the information presented in the f-chart is location independent. Methods of estimating the performance of air heating systems having a collector air capacitance rate and a storage capacity other than those used to generate the f-chart are included. A comparison of the performance of air and liquid based systems is afforded by a comparison of their respective f-charts. The air system is shown to perform better at high load fractions supplied by solar energy than a liquid-based system with the same collector thermal performance parameters. 相似文献
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This paper consists of two parts. The first part provides a graphical method of determining, under different operating conditions, the design data for a system using air heaters of known characteristics, i.e. of known η vs (Δtm/I) curves for different flow rates. The interdependent operating parameters are the inlet and outlet fluid temperatures and the fluid flow rate. The unknown third parameter, when two others are fixed, is determined by the application of a design procedure outlined in the first part of the paper. The fluid rate per unit area is usually specified when presenting an air heater performance curve. However, while maintaining the same fluid flow rate per unit area, different curves are obtained for air heaters of different dimensions. Explicit importance to this fact does not seem to have been given in the literature so far. A methodology, by which performance curves obtained from a certain air heater of specific dimensions can be suitably modified so as to predict the performance of similar heaters having different dimensions, constitutes the second part of the paper. 相似文献
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何谓“全天候太阳能热水系统”,简单的说就是一年365天、每天24小时,时时都有热水备用的太阳能热水系统及工程。让用户(包括集体用户和家庭用户)再也不用为“现在洗浴有热水吗”而操心。它比过去使用过的“天天有热水”,实际上是天天的某个时段才有热水的承诺有更加明确的概念界限。也让用户遇到阴雨风雪等恶劣天气环境时无后顾之忧。 相似文献
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W.F. Phillips 《Solar Energy》1981,26(2):175-180
A theoretical model is presented which predicts the effects of stratification in the rock bed storage unit of a solar air heating system. The results are presented in terms of a stratification coefficient which is defined to be the ratio of the actual useful energy gain to the energy gain that would be achieved if the rock bed were maintained at a uniform temperature. This stratification coefficient is shown to be a system constant which depends on only three dimensionless system parameters. 相似文献
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An analytic model is presented for the prediction of the monthly and yearly thermal performance of solar air heating systems. The effects of stratification in packed rock bed storage are explicitly taken into account. An expression for monthly solar fraction that depends on the important system and climatic variables is derived, which affords accurate predictions compared to corresponding f-chart calculations. The value of our analytic model, vis-a-vis calculational tools such as f-chart, is discussed. The method is applicable to all solar collector types as well as to load distributions of other than 24 hr/day. 相似文献
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J. Naga Raju 《国际能源研究杂志》1991,15(6):469-471
Three types of conventional solar air heater are designed such that their heat absorbing areas and the pressure drops across them are equal for equal air mass flow rates per unit collector area. The results of thermal performance tests conducted simultaneously on these collectors, under the same environmental conditions, are presented. 相似文献
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M. T. Orozbaev 《Applied Solar Energy》2007,43(1):56-57
The technique and analytic expressions for determining the values of the thermotechnical parameters of the flat-plate solar air heating collectors are presented. These expressions are obtained on the basis of the laboratory and quasistationary full-scale experiments. 相似文献
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E. Taşdemiroǧlu 《Energy》1985,10(1):1-15
Life-cycle costing has been used in an economic analysis of three solar domestic hot water installations. These are in operation in Las Palmas (Canary Islands) and are backed by conventional installations consuming either fuel-oil (GG), butane (BB) or electricity (EE). The cumulative cost flows (CCF), including expenditures for purchase, recovery, maintenance, fuel and operating costs, are calculated over the useful life of the installations for expected annual fuel-increment rates. Twenty-seven comparisons are made between the solar (SAS) and conventional systems (CS). Total savings are found over the lifetime and the repayment periods are obtained as a function of discount rate. The SAS and CS are examined with respect to economic incentives such as subvention, tax deduction, loans and their combinations. Finally, the variations of the payback periods and rates of return on investment (IRR) are plotted against the fuel price, annual fuel increment rate and initial investment in the SAS for a wide range of economic parameters. 相似文献
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Paul R. Barnes 《Solar Energy》1981,26(4):375-376
The optimization of a solar system with a limited number of discrete collection areas available has been discussed. This optimization is based on an exponential relationship between the auxiliary energy required and collector area. In most cases, the optimum area is that area formed by an array of collector panels which is closest to but greater than Aop. In many cases, an even larger collection area can be used without a severe economic penalty since the cost curve changes slowly as collector area is increased. Larger collector areas are also preferable from the standpoint of reducing our dependence on non-renewable fuels. 相似文献
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Energy savings for solar heating systems 总被引:1,自引:0,他引:1
In this paper the realistic behaviour and efficiency of heating systems were analysed, based on long term monitoring projects. Based on the measurements a boiler model used to calculate the boiler efficiency on a monthly basis was evaluated. Comparisons of measured and calculated fuel consumptions showed a good degree of similarity. With the boiler model, various simulations of solar domestic hot water heating systems were done for different hot water demands and collector sizes. The result shows that the potential of fuel reduction can be much higher than the solar gain of the solar thermal system. For some conditions the fuel reduction can be up to the double of the solar gain due to a strong increase of the system efficiency. As the monitored boilers were not older than 3 years, it can be assumed that the saving potential with older boilers could be even higher than calculated in this paper. 相似文献