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。     

CPC型聚光光伏光热系统的性能分析

根据能量守恒定律,建立了分析CPC型聚光光伏光热系统性能的动态模型,并研究了系统的结构尺寸、冷却水流量等参数对系统性能的影响。当冷却水流量一定时,随着系统长度的增加,系统日发电效率和系统日集热效率逐渐降低。当系统长度一定时,增加冷却水流量能降低冷却水的出口温度,提高系统的发电效率。但是,随着冷却水流量的逐渐增加,各指标的变化趋势将逐渐平缓,系统的发电效率与水温之间存在一个基于流量的优化关系。     

光伏/光热联合空气源热泵系统的性能研究

为了改善传统光伏发电系统的运行性能,提出了一种光伏/光热(PV/T)联合空气源热泵系统,介绍了该系统的工作原理和运行方式,研究了该系统的综合性能评价方法,然后利用TRNSYS瞬时系统模拟软件建立了该系统的仿真模型,并以重庆地区为例,对比分析了PV/T联合空气源热泵系统与单一光伏发电系统的组件表面温度、热效率、电效率、?效率和一次能源节约效率。研究结果表明：1) PV/T组件表面温度与光伏组件表面温度的变化趋势较为一致,二者的平均值相差13℃,说明PV/T联合空气源热泵系统可以有效降低光伏组件表面温度;2) PV/T联合空气源热泵系统和光伏发电系统的平均电效率分别为11.40%和9.86%,相对提高了15.62%,说明PV/T联合空气源热泵系统能够获得更多的电能;3) PV/T联合空气源热泵系统和光伏发电系统的?效率平均值分别为11.73%和8.94%,相对提高了31.21%,说明PV/T联合空气源热泵系统能够获得更多的可用能;4) PV/T联合空气源热泵系统的平均一次能源节约效率为50.94%,其总体变化趋势与热效率的变化趋势相似。     

太阳能光伏光热建筑一体化系统的研究

太阳能光伏光热一体化不仅能够有效降低光伏组件的温度,提高光伏发电效率,而且能够产生热能,从而大大提高了太阳能的转换效率。对光伏光热建筑一体化(BIPV/T)系统的两种主要模式:水冷却型和空气冷却型系统的工作原理和系统模型进行了理论介绍,详细说明了两种系统中热产品在家庭中的应用。并对目前研究情况下两个系统中存在的问题提出了改进方案。与常规建筑相比,光伏光热建筑减少了墙体得热,改善了室内空调负荷状况,提高了建筑节能效果。     

聚光型太阳能光伏光热系统研究进展

聚光型太阳能光伏光热系统(CPV/T)在传统光伏发电系统的基础上增加了聚光系统和光热系统,在通过聚光系统提高光伏效率的同时将系统中多余的热量加以利用,以达到太阳能最大化利用的目的。本文介绍了CPV/T系统的工作原理及其能效影响因素,以直接影响系统太阳能综合利用效率的聚光器技术、光伏电池技术和光伏冷却技术作为分析对象,结合近几年国内外最新研究成果比较了不同类型聚光器、光伏电池以及冷却方式的优劣,列举了常见的光伏余热利用方式。分析认为:CPV/T系统虽然具有更高的太阳能利用率,但应加大对系统尤其是聚光器经济性的分析;考虑在系统中应用叠层光伏电池缓解聚光器带来的系统体积过大问题;新电池开发过程中应更注意光伏电池的温度系数以减少冷却系统的压力,冷却技术在强化散热的同时也应注意热量的收集方法及其与利用途径的有效结合。     

太阳能光伏光热一体化系统的实验研究

为提高太阳能的利用率同时得到可资利用的热水和电力，将小型贮能式光伏系统与家用平板型太阳能热水器结合起来，把光优电池组件层压在热水器的扁盒式铝合金集热板上，构成一套光优光热(PV／T)一体化系统，并在合肥地区进行了自然循环模式下的光电光热性能测试。实验结果表明，在晴朗或多云的天气条件下实验系统日平均热效率可达40％，日平均发电效率约9．5％，系统综合性能效率多在60％以上，比单独的光伏或热水系统效率有显著提高。     

两种不同结构的光伏光热一体化系统的性能分析

文章对光伏光热一体化热泵(PV/T-HP)系统和光伏光热一体化热管(HP-PV/T)系统进行了对比实验,并分析了这两种PV/T系统的热水温度、光热转化效率、光电转化效率、光伏电池板温度、火用效率以及一次能源节约效率等参数。研究结果表明:PV/T-HP系统的光热转化效率、光电转化效率相对较高;通过火用效率分析可知,以节约用电或发电为主要目的时,宜采用HP-PV/T系统;通过一次能源节约效率分析可知,PV/T-HP系统节约化石能源的能力要优于HP-PV/T系统,并且以供热为主要目的且需热量较大时,适宜采用PV/T-HP系统。     

光伏光热一体式阳台壁挂系统

将光伏与光热结合起来,开发了一款新型的阳台壁挂系统。描述了产品的关键技术,分析了产品的优点和技术之处,阐述了该产品市场推广的价值。     

光伏光热系统导热流道传热性能的数值模拟

对光伏光热系统实体模型进行简化处理,并建立了包含单条流道、带翅片的单条流道、单侧排列两条流道的三种型式导热流道的物理模型。以20℃蒸馏水为流动工质,借助FLU-ENT分别对三种不同型式的导热流道的传热性能展开数值模拟研究,分析了导热流道的出口平均温度和壁面导热速率。     

联合热泵的光伏光热一体化系统的性能评价

建立了联合热泵的光伏光热一体化系统和水冷式光伏光热一体化系统的数学模型,比较了两者的光伏电池温度、热水温度、电效率、热效率以及能量收益。研究结果表明,联合热泵的光伏光热一体化系统的光伏电池温度远低于水冷式光伏光热一体化系统,能达到较高的电效率和热效率。通过分析得出:联合热泵的光伏光热一体化系统的能量收益低于水冷式光伏光热一体化系统,但在以供热为主的情况下,联合热泵的光伏光热一体化系统具有明显的优势。     

Exergoeconomic analysis of glazed hybrid photovoltaic thermal module air collector

In this paper, an exergoeconomic analysis has been carried out and on the basis of this analysis it has been concluded that in terms of energy saving the glazed hybrid photovoltaic thermal (PVT) module air collector offers a greater potential compared to PV module. The experimental validation for glazed hybrid PVT module air collector has also been performed and it has been observed that there is a good agreement between the theoretical and experimental values with correlation coefficient in range of 0.96–0.99 and root mean square percentage deviation in range of 2.38–7.46. The experiments have been carried out on clear days during the month July 2010 to June 2011. For the validation of theoretical results with experimental results, a typical day of winter month (December 08, 2010) and summer month (April 11, 2011) has been considered. An experimental uncertainty for December and April month is 11.6% and 2.1% respectively. The annual overall thermal energy and exergy gain are 1252.0 kWh and 289.5 kW h respectively. The annual net electrical energy savings by glazed hybrid PVT module air collector is 234.7 kW h.     

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。     

An experimental implementation and testing of a concentrated hybrid photovoltaic/thermal system with monocrystalline solar cells using linear Fresnel reflected mirrors

Integration of solar concentrators with photovoltaic (PV) systems reduces the required number of PV panels, which often account for the major costs of PV systems. The linear Fresnel reflector mirror is considered more effective because of its simplicity and effortless fabrication. An experimental test rig of a concentrated PV/thermal system that employs a linear configuration and horizontal absorber was built for evaluating its electrical and thermal performances. The considered concentrator consists of various widths of flat glass mirrors, which positioned with different angles, and with sun light focusing on the PV cells that fixed over an active cooling system. The experimental investigation of the proposed concentrated PV/thermal system shows that higher electrical and thermal efficiencies can be achieved at comparatively high temperature levels than that typically utilized in a nonconcentrated PV/thermal system. The characteristics of PV cells also indicate that the electrical efficiency values in case of no concentration and with concentration ratio of 6.0 are 9.6%, and 11%, respectively. The measured values for the inlet and outlet cooling water temperatures of the receiver showed that the maximum outlet temperature reached was 75°C with a flow rate of 0.025 L/min, and the product thermal efficiency was 62.3%. These obtained results illustrate an adequate and good thermal and electrical performance under the meteorological weather conditions of the province of Al‐Karak in Jordan.     

An experimental study of hybrid photovoltaic thermal (PV/T)-active solar still

In this paper a new self-sustainable hybrid photovoltaic thermal (PV/T)-integrated-active solar still has been designed and tested for composite climate at I.I.T. New Delhi (28°32′N, 77°12′E). The PV system is used to generate electricity to run the pump (60 W and 18 V) as well as thermal energy to heat the water in the collector. The proposed design of hybrid-active solar still can be used at any remote location because of its self-sustainability. The experiments were performed on the set-up for different water depths and for different running duration of the pump. It has been observed that the hybrid-active solar still gives a higher yield (more than 3.5 times) than the passive solar still. It has also been observed that the daily distillate yield and thermal efficiency of the hybrid-active solar still remain almost the same for all water depths in the basin by reducing the daily running period of the pump from 9 to 5 h. This running period of the pump reduced saves 43% of the power used to run the pump with 9 h running, without affecting the performance of the solar still. This work also deals with exergy analysis of the system. Copyright © 2008 John Wiley & Sons, Ltd.     

Field study of various air based photovoltaic/thermal hybrid solar collectors

In the present work a comparative study for thermal and electrical performance of different hybrid photovoltaic/thermal collectors designs for Iraq climate conditions have been carried out. Four different types of air based hybrid PV/T collectors have been manufactured and tested. Three collectors consist of four main parts namely, channel duct, glass cover, axial fan to circulate air and two PV panels in parallel connection. The measured parameters are, the temperature of the upper and the lower surfaces of the PV panels, air temperature along the collector, air flow rate, pressure drop, power produced by solar cell, and climate conditions such as wind speed, solar radiation and ambient temperature. The thermal and hydraulic performances of PV/T collector model IV have been analyzed theoretically based on energy balance. A Matlab computer program has been developed to solve the proposed mathematical model.The obtained results show that the combined efficiency of collector model III (double duct, single pass) is higher than that of model II (single duct double pass) and model IV (single duct single pass). Model IV has the better electrical efficiency. The pressure drop of model III is lower than that of models II and IV. The root mean square of percentage deviations for PV outlet temperature, and thermal efficiency of model IV are found to be 3.22%, and 18.04% respectively. The calculated linear coefficients of correlation (r) are 0.977, 0.965 respectively.     

Energy and exergy analysis of a hybrid photovoltaic thermal double pass air collector

In this paper an attempt has been made to analyze the performance of semi transparent hybrid PVT double pass air collector. Based on the first law of thermodynamics, energy balance equations are for-mulated to derive the analytical expression for air temperature at the outlet, as a function of the design and climatic parameters for investigating the performance of semi transparent hybrid PVT air collector. The analysis is based on quasi-steady state condition. This paper shows the detailed analysis of energy and exergy of a semi transparent hybrid PVT double pass air collector and its comparison with single pass air collector for four weather conditions (a, b, c and d type) for five different cities (New Delhi, Bangalore, Mumbai, Srinagar, and Jodhpur) of India. It has been analyzed that if such systems are installed only at 10% of the total residential houses in Delhi, then the total carbon credits earned by the system is found to be Rs. 1767 millions in terms of thermal energy and Rs. 493 millions in terms of exergy for double pass air collector whereas Rs. 1528 millions in terms of thermal energy and Rs. 446 millions in terms of exergy for single pass air collector. The results clearly shows that hybrid PVT double pass air collector have better performance as compared to single pass air collector.     

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。     

Performance analysis of a hybrid photovoltaic thermal double pass air collector using ANN

This paper presents the use of artificial neural network for performance analysis of a semi transparent hybrid photovoltaic thermal double pass air collector for four weather conditions (a, b, c and d type) of New Delhi. The MATLAB 7.1 neural networks toolbox has been used for defining and training of ANN for calculations of thermal energy, electrical energy, overall thermal energy and overall exergy. The ANN model uses ambient air temperature, global solar radiation, diffuse radiation and number of clear days as input parameters for four weather conditions. The transfer function, neural network configuration and learning parameters have been selected based on highest convergence during training and testing of network. About 2000 sets of data from four weather stations (Bangalore, Mumbai, Srinagar, and Jodhpur) have been given as input for training and data of the fifth weather station (New Delhi) has been used for testing purpose. It has been observed that the best transfer function for a given configuration is logsig. The feedforward back-propagation algorithm has been used in this analysis. Further the results of ANN model have been compared with analytical values on the basis of root mean square error.     

An experimental evaluation of R11 as a heat pump working fluid in comparison with some other working fluids

A water to water heat pump specially designed and instrumented for research has been used to determine the actual coefficients of performance of R11 for condensing temperatures in the range 70°C to 104°C. 101 experimental points were obtained and these lie on a smooth curve with a standard deviation of 6.32 per cent. The results are compared with data previously obtained for R12, R22, R12B1 and R114 on the same equipment. R11 with its relatively high critical temperature of 198°C is potentially an attractive working fluid provided that it can be operated in conjunction with a lubricant which does not facilitate thermal breakdown.