真空太阳集热管在应用不同吸气剂时的残气分析

自行设计了可直接测量成品集热管夹层真空状况的装置,对集热管夹层内真空度进行测量,并验证了该装置的可靠性.利用该真空开管装置分析了使用不同吸气剂的集热管内残余气体的情况.     

室温对全玻璃真空太阳集热管平均热损系数的影响

引言 平均热损系数（ULI）是判定全玻璃真空太阳集热管热性能的一个重要技术指标。它是指在无太阳辐照条件下，全玻璃真空太阳集热管内充满80℃热水时，通过真空集热管向周围环境传递热能，水温下降，管内平均水温与环境温度相差1℃时，吸热体单位表面积散失的功率。全玻璃真空太阳集热管的热损系数取决于选择性吸收表面的发射比大小和真空夹层内的气体压强，因此热损系数的大小可以综合地反映吸收表面发射比和夹层的真空度好坏，较主要地决定着真空集热管的高温性能。     

真空集热管热性能与其特性参数之间的关系

真空集热管热性能与其特性参数之间的关系桂裕宗全玻璃真空太阳集热管的主要热性能———闷晒温度、空晒温度和平均热损系数，基本上决定于集热管玻璃的太阳透射比、吸收涂层的太阳吸收比和半球向发射率，以及真空夹层的真空度．１闷晒温度、热损系数与集热管玻璃的太阳...     

全玻璃真空太阳集热管规模生产的质量管理

全玻璃真空太阳集热管规模生产的质量管理严锡元牛传瑾全玻璃真空太阳集热管（以下简称集热管）的生产，在我国，从清华大学殷志强教授等研制出第一支集热管开始，仅有十多年历史，至于大批量生产，则是最近二、三年的事．清华大学太阳能电子厂于１９９４年建成一条年产１...     

国家标准《全玻璃真空太阳集热管》修订审定会召开

国家标准GB／T17049-1997《全玻璃真空太阳集热管》修订审定会于2004年9月23日在云南省丽江市召开。本标准修订的主要内容为：1．适当提高全玻璃真空太阳集热管及其材料的光一热性能参数；2．增加罩玻璃管直径Ф58mm为全玻璃真空太阳集热管；3．增加全玻璃真空太阳集热管的真空品质检测；4．增加了采用钢球进行机械冲击试验的内容。     

太阳能热利用

一种家用太阳能吸附式中央空调；一种全玻璃真空太阳集热管的尾部固定结构；一种全玻璃真空太阳集热管；可避免真空集热管破裂的太阳能热漏洞百出器；海水源热泵机组[编者按]     

全玻璃真空太阳集热管光—热性能

从能量平衡议程导出全玻璃真空太阳集热管的3个光－热性能参数,即热损系数UTL、闷晒太阳曝辐量H和空晒性能参数Y与真空热管理的罩管玻璃的太阳透射比τ、选择性吸收表面的太阳吸收比a、发射比ε、和集热管内的气体压强p,太阳辐照度、环境温度和真空太阳集热管的几何尺寸等函数关系。理论计算的真空太阳集热管的3个热性能参数与实验的结果比较一致。上述全玻璃真空太阳集热管的光－热性能参数已经被国家标准《全玻璃真空太阳集热管》（GB／T17049－1997）采用。     

全玻璃真空集热管大面积太阳热水器的安装调试和维护

全玻璃真空集热管大面积太阳热水器的安装调试和维护刘海涛李德坚我们为山东省即墨市田横岛渡假村利用梯田地势安装了一个３５０ｍ２的大面积太阳热水器，一年四季可为旅游者提供生活用热水，用户十分满意．本文总结了几年来我们安装全玻璃真空集热管大面积太阳热水器的经...     

全玻璃真空太阳集热管（器）寿命测试方法的分析

综述了太阳集热管（器）寿命研究及选择性吸收材料老化性能检测方法的研究进展,分析认为单盖板平板型太阳集热器寿命研究同太阳选择性吸收材料的老化性能的检测方法一样要考虑温度（循环）、湿度及环境气氛的影响,而全玻璃真空太阳集热管（器）在长期运行过程中则会发生惰性气体及水分通过罩管玻璃向夹层渗透、吸气剂的变化而降低夹层真空度,气体导热损失增大,涂层（镀膜）和基底材料的相互作用、罩管积灰（尘）及内管结垢等改变涂层（镀膜）的光学性能,进而导致热性能的降低。最后,提出全玻璃真空太阳集热管（器）的寿命研究并形成检测方法的基本思路。     

全玻璃真空集热管热损计算与分析

根据热量传递原理,对全玻璃真空太阳集热管的热传导、对流和辐射三种传热形式进行了推导计算,其中辐射热损对真空集热管热损的贡献起主要作用,且辐射热损随温度升高而增大.根据串联电阻叠加原则得出真空集热管主体热损的计算模型,并通过该理论模型计算了全玻璃真空集热管的热损.结果表明,理论计算的热损值均小于测试的热损值,这是由于集热管的边端热损效应引起的.     

Fabrication and testing of a non-glass vacuum-tube collector for solar energy utilization

An evacuated tubular solar collector was fabricated from acrylics for improved resistance to shattering. A plasmatron was employed to apply a thin gas-barrier coating to the surfaces of the plastic tube to prevent/alleviate gas infiltration. Experiments were conducted to investigate the effect of vacuum level on the performance of the non-glass vacuum-tube solar collector. Inserted in the evacuated tube was a finned heat pipe for solar energy collection and heat transfer to a water tank. Time variations of temperatures on the heat pipe surface and in the water tank were recorded and analyzed for different degrees of vacuum in the collector. The steady-state temperature of the non-glass collector was compared to that of a commercial glass vacuum-tube collector to assess the feasibility of the use of evacuated plastic tubes for solar energy collection. A simple analytical model was also developed to assist in understanding and analyzing the transient behavior and heat losses of the vacuum-tube solar collector.     

CPC热管式真空管集热器的集热效率研究

介绍了CPC(compound parabolic concentrator)热管式真空管集热器的结构,对CPC热管式真空管太阳能集热器进行了传热分析,并对CPC热管式真空管集热器、热管式真空管集热器和CPC热管式集热器的集热效率进行了对比计算。CPC热管式真空管集热器的集热效率的理论计算和试验结果表明:CPC热管式真空管集热器的集热效率最佳。     

Simulation and experimental investigation of two hybrid solar domestic water heaters with drain water heat recovery

In this paper, the performance of two solar domestic hot waters (SDHW) with drain water heat recovery (DWHR) units is investigated. Both SDHW systems are recently installed at the Archetype Sustainable Twin Houses at Kortright Center, Vaughan, Ontario. The first SDWH system in House A consists of a flat plate solar thermal collector in combination with a gas boiler and a DWHR unit. The second SDHW system in House B includes an evacuated tube solar collector, an electric tank, and a DWHR unit. Both systems are modeled in TRNSYS, and the models are validated by experimental data. The addition of the DWHR and the flat‐plate solar thermal collector would result in 1831 kWh of annual energy saving in House A. While the addition of the DWHR and the evacuated tube collector in House B would result in an annual energy saving of 1771 kWh. Subsequently, the models are used to investigate the performance of similar systems for five major Canadian cities of Halifax, Montreal, Toronto, Edmonton, and Vancouver. The conjunctions of solar thermal collectors with DWHR units are found most beneficial in Edmonton. It is also noted from experimental and simulated results that flat‐plate solar collector‐based water heater produced more thermal energy than the system based on the evacuated tube solar collector for all major Canadian cities. Copyright © 2015 John Wiley & Sons, Ltd.     

A comparison of optical performance between evacuated collector tubes with flat and semicylindric absorbers

In this article, concepts of solar irradiance ratio and absorbed energy factor on the surface of the evacuated collector tube absorbers were presented respectively. For evacuated collector tubes with flat and semicylindric absorbers, we used a solar simulator as a light source, measured separately distribution of the solar irradiance ratio that varies with incident angles on various points on the absorber surface in a glass-covered tube, and gave their three-dimensional regressive equations correspondingly. Experimental measurement of solar irradiance ratio and solar absorptance of coatings on absorber surfaces was carried out. On this basis, rules of absorbed energy factors on absorbers in two shapes that vary with incident angles were analyzed and studied. According to clear-day model, the daily absorbed energy and its annual changes of single evacuated collector tubes with absorbers in two shapes placed under 40° northern latitude, 40° inclined angle and south orientation were calculated and compared. The results show that the annual absorbed energy of evacuated collector tube with a semicylindric absorber is 15.9% higher than that with a flat absorber. In addition, optimized incident angles for the absorber in two shapes of evacuated collector tubes operated in a whole year were tentatively investigated.     

热管式真空管集热器的热性能研究

在传热分析的基础上，提出了确定热管式真空集热器的总热损系数、效率因子和热转移因子的计算方法，通过实验，还分别测定了单根真空管和真空管集热器的瞬时效率曲线。实验结果与理论计算值符合较好。     

带内遮热板真空集热管的研究

为降低全玻璃真空集热管在较高温度工作时的辐射传热热损,提出两种带内遮板的真空集热管管型,对其传热过程进行分析,计算各管型的辐射热损。讨论真空管各项性能参数对其热性能的影响,结果表明带内遮板的真空集热管在较高温度工作时具有十分优越的性能。     

Determination of emittance of selective absorbing surfaces

The hemispherical emittance of the selective absorbing coating on the outside of the inner glass tube of an all-glass evacuated collector tube has been determined, using calorimetry at steady state in the temperature range 50–300°C and gas pressure range 1.0×10⁻³–1.6 Pa at the jacket between cover and inner glass tubes. Calculated gas heat flux q_c and equivalent emittance _g based on the theory of gas conduction at medium and low pressures have been determined. The calculations agree well with experiments. The experimental results indicate that heat losses of all-glass evacuated collector tubes due to gas convection and conduction are negligible when the gas pressure in the tube is less than 5×10⁻² Pa.     

Experimental and theoretical evaluation of the overall heat loss coefficient of vacuum tubes of a solar collector

The overall heat loss coefficient (U-value) of a vacuum tube solar collector is investigated experimentally and theoretically with regard to the pressure of the remaining gas inside the evacuated glass envelope. A number of collector tubes of same geometry are randomly selected from an installation of a solar based air-conditioning system and tested individually in the laboratory for the determination of the U-value. Measurement results indicate that most of the examined collector tubes have higher overall heat loss coefficients than expected corresponding to a significant amount of gas inside the glass envelope.For the same conditions, an approximate theoretical model is developed for the evaluation of the U-value. The theoretical model is validated against the experimental results for a collector tube having air inside the glass cover at atmospheric pressure and found to be in close agreement. Then, the influence of gas pressure is studied for various gases. Possible presence of air, hydrogen, helium and argon is discussed.     

Numerical and experimental investigation of operating parameters of solar–powered desiccant wheel in India

A mathematical model has been used to predict the operating parameters of a desiccant wheel for performance analysis of the desiccant wheel. The model considered both gas and solid side resistance. The model shows a good agreement with experimental data. An experimental setup was fabricated using an evacuated tube solar air collector with a desiccant wheel. The hot air needed for regeneration is produced by the evacuated tube solar air collector, which has a collector surface area of 4.44 m² . The regeneration can be started from 40 °C. The temperature of outlet air obtained is in the range of 40–65 °C in this evacuated tube solar air collector. The experimental setup was installed at NIT Kurukshetra, India, 29° 58′ (latitude) North and 76° 53′ (longitude) East. Numerical results showed that both the moisture removal and the temperature increment of the process air increases with an increasing regeneration air temperature, regeneration air inlet velocity, and process inlet moisture. But both the moisture removal and the temperature increment of the processed air decreases by increasing the process air inlet velocity and regeneration air moisture at the inlet. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21031