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应用层次分析法综合评价家用太阳热水器 总被引:1,自引:0,他引:1
采用层次分析法对家用太阳热水器的热性能,经济性,可靠性以及使用寿命等多项因素进行综合评价。通过建立评价家用太阳热水器的层次结构及确定评价指标,借助计算机计算模型,可简捷,方便地排出各种不同型式家用太阳热水器的优劣,为用户选择产品和生产厂家优化设计提供依据,也可用来作为评比太阳热水器的一种方法。 相似文献
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张道文 《小型内燃机与摩托车》2009,38(1)
选取了模糊综合评判决策作为代用燃料发动机综合性能的评价方法,建立了评价模型.用这个模型对CNG/汽油两用发动机的综合性能进行了评价,说明该评价模型有一定适用性. 相似文献
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20世纪 90年代以来,我国太阳热水器产业发展十分迅速,目前产销量均居世界首位。这就迫使我们思考,采用什么指标对热水器进行评价才能更好地反映它的热性能 ?另外,预测一个热水器在不同气象条件下的性能,对用户和生产厂家也都十分必要。1太阳热水器热性能评价指标体系 (1)评价指标体系组成 笔者认为,以太阳热水器得热量、水的温升以及热损系数作为太阳热水器热性能评价指标较为合适。下面通过能量平衡方程推导得热量的解析表达式。 太阳热水器的能量平衡方程:(τα )AH=Mcp· (te- ti)+ UL(te- ta)Δτ+ S (1) … 相似文献
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关于太阳热水器热性能评价指标 总被引:1,自引:0,他引:1
拜读了在《太阳能学报》(2 0 0 0年第 3期 )和《太阳能》(2 0 0 0年第 4期 )上发表的有关太阳热水器热性能评价与预测的文章 (以下简称为该文 ) ,该文提出了以热水器日得热量Q、水的温升te-ti 和热损系数UL 作为太阳热水器热性能的评价指标。其中热水器得热量采用排水法 ,并经过回归 ,得到热水器日得热量和水的温升的预测公式。文中还推得了一个有关热损系数的公式。笔者对其中的一些观点不敢苟同 ,对其中的一些方法和公式也存有疑问 ,在此提出 ,与各位同行共同商讨。1 关于评价指标作为一个评价指标 ,它应具有概念上的科学性、分析… 相似文献
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Nehrir M.H. Lameres B.J. Venkataramanan G. Gerez V. Alvarado L.A. 《Energy Conversion, IEEE Transaction on》2000,15(4):433-439
This paper reports the development of a computer approach for evaluating the general performance of stand-alone wind/photovoltaic generating systems. Simple models for different system components are developed, integrated, and used to predict the behavior of generating systems based on available wind/solar and load data. The model is useful for evaluating the performance of stand-alone generating systems and gaining a better insight in the component sizes needed before they are built. Simulation results are presented for performance evaluation of a stand-alone generating system that has been previously designed to supply the average power demand of a typical residential house. An electric water heater model is used as a dump load, and the excess available wind/solar-generated power is used to heat the water. The heated water is used as the inlet water to the main house water heater, which is assumed to be nonelectric. It is shown that this strategy can be effective in reducing the amount of fuel used by the main residential water heater 相似文献
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文章建立了三维非稳态的全玻璃真空管太阳热水器的数值模型,分析了夜间散热时,该热水器内的流动和传热特征,并且在夜间同一工况下,模拟研究了贮热水箱保温材料的导热系数、保温厚度,以及真空管涂层的发射率对贮热水箱温度、真空管温度和该热水器夜间热损失的影响。分析结果表明:随着散热过程的持续进行,全玻璃真空管太阳热水器内温度分层情况越来越明显,内部流体的流速越来越小,真空管内静滞区域自下往上逐渐扩大;当贮热水箱保温材料的导热系数由0.035 W/(m·℃)减小至0.020 W/(m·℃)时,该热水器的夜间热损失减少了8.5%;当贮热水箱保温厚度由50 mm增加至60 mm时,该热水器的夜间热损失减少了5.0%;当真空管涂层的发射率由0.06减小至0.05时,该热水器的夜间热损失减少了4.0%。 相似文献
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Yemeli Wenceslas Koholé 《国际可持续能源杂志》2017,36(5):430-449
The paper presents a comparative study of three solar water heaters made of flat-plate collectors with different absorber configurations. The performance of the three solar water heaters is assessed under the same conditions. The collectors have the same surface area and are glazed. The theoretical model for each collector type, with the transient effects taken into account, is based on a control volume. By considering a small element of the collector in each case and the storage tank, six partial differential equations were developed for each solar water heater and were solved numerically for a cloudy day. This study shows that the thermal performance obtained with the solar water heater using the absorber-pipe lower bond configuration in the solar collector is always greater than the two others. These results showed that the solar water heater made of the absorber-pipe lower bond configuration is more efficient than the other systems. 相似文献
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Experimental investigation on thermal performance of thermosyphon flat-plate solar water heater with a mantle heat exchanger 总被引:1,自引:0,他引:1
The thermal performance of thermosyphon flat-plate solar water heater with a mantle heat exchanger was investigated to show its applicability in China. The effect on the performance of the collector of using a heat exchanger between the collector and the tank was analyzed. A “heat exchanger penalty factor” for the system was determined and energy balance equation in the system was presented. Outdoor tests of thermal performance of the thermosyphon flat-plate solar water heater with a mantle heat exchanger were taken in Kunming, China. Experimental results show that mean daily efficiency of the thermosyphon flat plate solar water heater with a mantle heat exchanger with 10 mm gap can reach up to 50%, which is lower than that of a thermosyphon flat-plate solar water heater without heat exchanger, but higher than that of a all-glass evacuated tubular solar water heater. 相似文献
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文章从传热学的角度提出一种适用于低压加热器变工况运行时的优化计算方法。介绍了低压加热器的功能原理及传热过程。分析了给定端差计算法的局限性。构建了优化的低压加热器内部传热理论模型并对其求解过程进行了描述。给出了定面积和定端差2种不同情况下,加热器参数与给水参数的变化关系曲线。根据计算结果对加热器在变工况条件下运行时的参数特性进行了分析。 相似文献
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