槽式聚光太阳能热电联供复合循环

提出一种新型的太阳能光伏发电与供热复合循环系统,该复合循环系统有效利用太阳辐射能量,提高光伏系统电池功率,并将光伏电池所产生的热量有效回收,实现同一聚光集热器对外供电、供热.构建了槽式聚光太阳能热电复合循环实验装置,实验表明,在10倍太阳聚光作用下,单晶硅电池功率可放大5.05倍,并可有效回收太阳电池所产生的热量.太阳能热电联供系统能有效提高太阳能综合利用率.     

一种快装式光伏光热一体化系统搭建及试验研究

研究一种快装式光伏光热(PVT)一体化热电联产系统,该系统将先进的微热管集热技术应用到分布式光伏发电领域,在不增加任何占地空间的基础上,快速实现真正的光伏光热一体化组件及热电联产系统。通过真实系统搭建,并经过试验数据验证,该系统不仅能够抑制太阳电池板工作时的温度升高,还能在一定程度上提高发电效率,光伏背板所产生的热能还可为用户提供热水需求,从而较大程度提高光电转换效率和低温热量利用率,实现更高的综合效率。     

太阳能光伏光热系统集热器连接方式的优化

集热器连接方式对强制循环式光伏光热(PVT)热水系统的运行性能存在较大影响,针对最佳连接方式的相关研究未见报道。综合考虑环境温度、太阳辐射量和热水负荷等因素,以12块平板型PVT集热器(2 m×1 m)为研究对象,利用Fortran语言建立不同连接方式PVT热水系统动态传热模型,并分别以发电量、实际集热量以及实际综合发电量为优化目标进行计算。结果表明:在两种不同工况下,获得最大发电量的连接方式都为N=1,而获得最大实际集热量的连接方式并不一致;综合全年性能分析,以发电量、实际集热量和实际综合发电量为优化目标时对应的最佳连接方式和最佳倾角组合形式分别为:N=1和β=20°,N=4和β=28°,N=3和β=26°。研究结果对大型太阳能集热器安装方式的选取具有参考价值。     

太阳电池冷却及光伏/光热一体技术的新进展

由于太阳电池光电转换效率随自身温度的升高而下降,因而对太阳电池进行冷却成为当前太阳能光伏研究的一项重要内容;同时,在太阳电池冷却的研究课题当中引申出了光伏与光热相结合(PV/T)的概念,使太阳电池转换而成的热量得以应用,这是新能源产业的一项重要发展趋势.收集并整理了近5年国内外的太阳电池冷却方法和光伏光热一体化研究成果...     

基于太阳能光伏热利用的光伏/热电(PV/TV)建筑一体化试验研究

将太阳能电池板、集热器、热电发电片结合起来,设计并制成了一套光伏/热电(PV/TV)系统,在利用太阳能电池发电的同时,收集热量并利用其发电。在北京地区进行了该系统的室外模拟试验,测试并讨论了该系统在不同结构和不同环境下的性能,探讨该系统在光伏建筑中的应用。试验结果表明,与单纯的光伏发电系统或太阳能热水系统相比,PV/TV系统具有占地面积小、综合效率高等优点。     

非晶硅太阳能光伏/光热空气集热器性能对比实验研究

文章设计了新型非晶硅太阳能PV/T空气集热器,该空气集热器能够解决传统太阳能PV/T热水器在高温波动情况下,晶硅电池热应力大的问题,同时避免了冬季管道发生霜冻的现象。文章通过实验对比,分析了非晶硅太阳能PV/T空气集热器、单独非晶硅光伏电池和传统太阳能空气集热器的能量效率和[火用]效率的差异。分析结果表明:非晶硅太阳能PV/T空气集热器的平均热效率为45.70%,比传统太阳能空气集热器的平均热效率降低了约25.88%;当空气质量流量增大至0.048 kg/s时,非晶硅太阳能PV/T空气集热器中的非晶硅光伏电池的平均电效率高于单独非晶硅光伏电池,它们的平均电效率分别为4.70%,4.54%;非晶硅太阳能PV/T空气集热器的总[火用]效率高于传统太阳能空气集热器的热[火用]效率和单独非晶硅光伏电池的电[火用]效率,非晶硅太阳能PV/T空气集热器总[火用]效率最大值为7.14%。文章的分析结果为非晶硅太阳能PV/T空气集热器的推广提供了参考。     

水冷型PV/T集热器的换热性能研究

光伏/光热(Photovoltaic/Thermal,PV/T)集热器集光伏发电与太阳能低温热利用于一体,可以同时输出电和热,是前景较好的新型太阳能利用技术。文章利用Fluent软件数值模拟了多进多出形式的水冷型PV/T集热器,分析了水的入口温度、流速及辐射强度对光伏电池温度及出口水温的影响。研究显示,在最佳匹配条件下,集热器的光电转化率和光热转化率能得到综合提高。     

太阳能光伏光热一体化系统运行实验研究

太阳能光伏光热一体化系统（hybrid photovoltaic-thermal solar system—PVT系统）作为一种利用太阳能同时获得电收益和热收益的新型能源利用方式,近年来受到学者的广泛关注。本文搭建了PVT系统电、热性能综合实验台,通过全天实验,分别研究和分析了系统的温度特性与相对电效率的关系。结果袁明,在日照条件较好,系统循环水温较低的情况下,PVT系统的电效率与普通光伏电池相比可以提高约7％。同时,文章还分析了PVT系统内水的温度一天内的变化情况,提出了在午后太阳辐射强度逐渐减弱,环境温度逐渐升高时如何保持PVT系统较高电效率的方法。     

太阳能的应用与发展

进入20世纪,开发利用太阳能经历了三个阶段:先是在本世纪前期,为热利用研究开发阶段,如美国此时已研建聚光集热器;接着到中叶,为继续发展利用和研制太阳电池阶段,主要工作为提高集热器效率,使用热水器,建太阳能采暖房和温室,对太阳能热电站进行先期     

太阳能光伏、光热及制冷一体机(上)

从对一般城镇居民用电结构的调查入手,通过对现有太阳能光伏系统能量转化和利用情况进行分析,确立了太阳能光伏、光热利用两条并行主线,提出了"以光变电、制热,用热制冷"的综合解决方案。通过设计新的反射聚光系统、由太阳电池板和集热器组成复合结构的光靶、集成吸收式制冷系统和仿生害羞虫避光式阳光跟踪传感器系统等,最终形成了太阳能光伏、光热和制冷功能一体化集成设计理念,以期通过整个系统的协调运行实现太阳能利用的高效率和经济性。     

On the Development of the Solar Photovoltaic and Thermal (PVT) Collector

The solar photovoltaic and thermal (PVT) collector is a device which converts solar energy into thermal and electrical energies simultaneously. The PVT collector can be used whenever both electricity and hot water are required, for example, for domestic uses. It is a known fact that the efficiency of the solar (photovoltaic) cells decreases as operating temperatures increase. Therefore, a better and a more efficient use of these cells, calls for cooling the cells. One method for doing that is to use a heat exchange system, which cools the cells by means of a heat absorbing medium, such as water, flowing in pipes. The heat removed from the cells results in hot water. Another advantage of the PVT collector is its higher overall efficiency per unit area and lower packaging costs due to its compact design. In this paper a theoretical analysis of the PVT collector using a simulation model is presented. In this model the PVT collector is divided into a matrix of ``small' PVT collector units, each one consisting of several layers. The energy balance of each ``small' PVT collector unit is studied by analysis of the energies entering and leaving each one of its layers. Later, the process is applied to the PVT collector itself. A PVT collector was designed and constructed and putthru a series of experiments under varying load conditions, insolation levels and other climatological conditions.     

Hybrid photovoltaic and thermal solar-collector designed for natural circulation of water

The electricity conversion-efficiency of a solar cell for commercial application is about 6–15%. More than 85% of the incoming solar energy is either reflected or absorbed as heat energy. Consequently, the working temperature of the solar cells increases considerably after prolonged operations and the cell’s efficiency drops significantly. The hybrid photovoltaic and thermal (PVT) collector technology using water as the coolant has been seen as a solution for improving the energy performance. Through good thermal-contact between the thermal absorber and the PV module, both the electrical efficiency and the thermal efficiency can be raised. Fin performance of the heat exchanger is one crucial factor in achieving a high overall energy yield. In this paper, the design developments of the PVT collectors are briefly reviewed. Our observation is that very few studies have been done on the PVT system adopting a flat-box absorber design. Accordingly, an aluminum-alloy flat-box type hybrid solar collector functioned as a thermosyphon system was constructed. While the system efficiencies did vary with the operating conditions, the test results indicated that the daily thermal efficiency could reach around 40% when the initial water-temperature in the system is the same as the daily mean ambient temperature.     

Performance analysis of a novel hydrogen production system incorporated with hybrid solar collector and phase change material

In this technical article, a novel experimental setup is designed and proposed to produce a hydrogen by using solar energy. This system comprises a hybrid or photovoltaic Thermal (PVT) solar collector, Hoffman's voltameter, heat exchanger unit and Phase Change Material (PCM). The effect of PCM and mass flow rate of water on the hybrid solar collector efficiency and hydrogen yield rate is studied. This experimental results clearly showed that by adding the thermal collector with water, decreases PV module temperature by 20.5% compared with conventional PV module. Based on the measured values, at 12.00 and 0.011 kg/s mass flow rate, about 33.8% of thermal efficiency is obtained for water based hybrid solar collector. Similarly, by adding Paraffin PCM to the water based thermal collector, the maximum electrical efficiency of 9.1% is achieved. From this study, the average value of 17.12% and 18.61% hydrogen yield rate is attained for PVT/water and PVT/water with PCM systems respectively.     

Detailed analysis of the energy yield of systems with covered sheet-and-tube PVT collectors

Solar cells have a typical efficiency in the range of 5-20%, implying that 80% or more of the incident solar energy can be harvested in the form of heat and applied for low-temperature heating. In a PVT collector one tries to collect this heat. In this work, the electrical and thermal yield of solar domestic hot water systems with one-cover sheet-and-tube PVT collectors were considered. Objectives of the work were to understand the mechanisms determining these yields, to investigate measures to improve these yields and to investigate the yield consequences if various solar cell technologies are being used. The work was carried out using numerical simulations.A detailed quantitative understanding of all loss mechanisms was obtained, especially of those being inherent to the use of PVT collectors instead of PV modules and conventional thermal collectors. The annual electrical efficiencies of the PVT systems investigated were up to 14% (relative) lower compared to pure PV systems and the annual thermal efficiencies up to 19% (relative) lower compared to pure thermal collector systems. The loss of electrical efficiency is mainly caused by the relatively high fluid temperature. The loss of thermal efficiency is caused both by the high emissivity of the absorber and the withdrawal of electrical energy. However, both the loss of electrical and thermal efficiency can be reduced further by the application of anti-reflective coatings. The thermal efficiency can be improved by the application of a low-emissivity coating on the absorber, however at the cost of a reduced electrical efficiency.     

An experimental study of façade-integrated photovoltaic/water-heating system

The worldwide fast development of building-integrated solar technology has prompted the design alternatives of fixing the solar panels on the building façades. How to make full use of an integrative system to achieve the best energy performance can be an important area in the technology promotion. Hybrid solar system applying in buildings has the advantage of increasing the energy output per unit installed collector area. This paper describes an experimental study of a centralized photovoltaic and hot water collector wall system that can serve as a water pre-heating system. Collectors are mounted at vertical facades. Different operating modes were performed with measurements in different seasons. Natural water circulation was found more preferable than forced circulation in this hybrid solar collector system. The thermal efficiency was found 38.9% at zero reduced temperature, and the corresponding electricity conversion efficiency was 8.56%, during the late summer of Hong Kong. With the PVT wall, the space thermal loads can be much reduced both in summer and winter, leading to substantial energy savings. Suggestions were given on how to further improve the system performance.     

商用太阳电池改造的光伏-光热组件传热性能分析

介绍了将传统晶体硅商用太阳电池加装水冷器,改造为光伏-光热集成组件后的结构;通过热阻分析的方法,分析了该光伏-光热组件的传热特性;并通过实验,实际测量了该光伏-光热组件的传热性能,得到了导热热阻及其有效热导率,可为组件的进一步开发提供参考。     

Performance evaluation of photovoltaic–thermosyphon system for subtropical climate application

The rapid development and sales volume of photovoltaic (PV) modules has created a promising business environment in the foreseeable future. However, the current electricity cost from PV is still several times higher than from the conventional power generation. One way to shorten the payback period is to bring in the hybrid photovoltaic–thermal (PVT) technology, which multiplies the energy outputs from the same collector surface area. In this paper, the performance evaluation of a new water-type PVT collector system is presented. The thermal collection making use of the thermosyphon principle eliminates the expense of pumping power. Experimental rigs were successfully built. A dynamic simulation model of the PVT collector system was developed and validated by the experimental measurements, together with two other similar models developed for PV module and solar hot-water collector. These were then used to predict the energy outputs and the payback periods for their applications in the subtropical climate, with Hong Kong as an example. The numerical results show that a payback period of 12 year for the PVT collector system is comparable to the side-by-side system, and is much shorter than the plain PV application. This is a great encouragement in marketing the PVT technology.     

Advancement in solar photovoltaic/thermal (PV/T) hybrid collector technology

This article presents an overview on the research and development and application aspects for the hybrid photovoltaic/thermal (PV/T) collector systems. A major research and development work on the photovoltaic/thermal (PVT) hybrid technology has been done since last 30 years. Different types of solar thermal collector and new materials for PV cells have been developed for efficient solar energy utilization. The solar energy conversion into electricity and heat with a single device (called hybrid photovoltaic thermal (PV/T) collector) is a good advancement for future energy demand. This review presents the trend of research and development of technological advancement in photovoltaic thermal (PV/T) solar collectors and its useful applications like as solar heating, water desalination, solar greenhouse, solar still, photovoltaic-thermal solar heat pump/air-conditioning system, building integrated photovoltaic/thermal (BIPVT) and solar power co-generation.     

Modelling of a hybrid photovoltaic thermal collector based on CdTe

A few years ago, silicon photovoltaic panels had yields of 10 to 18%, which made them interesting because is not profitable enough (too expensive to energy conversion yield too low).But recently, thin film technology appears to increase the efficiency and reduce the cost. For application in hybrid collectors, various types of solar photovoltaic hybrid collectors (PVT) based on new materials for solar cells have been developed as the binary semiconductor, ternary and quaternary materials and organic. CdTe is a the most appropriate binary materials for use in photovoltaic structures in thin layers, this material can produce a high yield of about 15% and is also known by a direct band structure gap of a value of 1.45 eV and a very high absorption coefficient (>105 cm^–1 in the visible). In this work we present the modeling of a hybrid photovoltaic thermal collector based on the thin films solar cells of CdTe, and then we made the determination of the temperature levels of the various layers through the development of the energy balance sheet involves heat exchange between the different components of the collector and to study its electrical and thermal performance, and finally compare their efficiency with it of the PVT collector based on monocrystalline silicon.