双玻光伏组件PV/T集热器特性及实验研究

利用双玻光伏组件设计了一种新的PV/T(photovoltaic/thermal)太阳能集热器,并对其热转换和传输特性进行研究。制备了透光率分别为50%和10%的2种双玻光伏组件PV/T空气集热系统样机,并对其特性进行实验研究。结果表明透光率50%的PV/T太阳能集热器,其吸热板温度高于双玻光伏组件温度,透光率10%PV/T太阳能集热器中吸热板温度低于双玻光伏组件温度,其最大温度差达到30℃,光伏组件受吸热板温度影响减小,且透光率50%集热系统输出空气温度达94℃,日热效率为49.2%,光伏组件输出效率达到9.5%,具有较好的实用性,实验结果与理论分析结果一致。研究为PV/T太阳能集热器优化设计提供了一种新的途径。     

太阳能PV/T集热系统性能优化研究

水工质太阳能PV/T(光伏/光热)集热技术可实现电热联产,应用潜力巨大,但在电热联产能量转化及系统优化方面的研究不够深入。文章采用验证后的TRNSYS模型,对水工质PV/T(光伏/光热)集热器及系统进行了优化研究。结果表明,在基准工况下,优化后的PV/T集热器发电效率、热效率和总效率相比优化前分别相对提升50.22%,27.47%和32.92%。以PV/T集热系统CO₂排放最低为优化目标,系统存在最佳工质质量流量、最佳温控器设置温差和最佳水箱体积,优化后的系统在杭州应用时,系统年度热效率、电效率和总效率分别为32.41%,18.65%和51.06%,并且该系统无论耦合电加热还是热泵,在CO₂排放或成本上都具有一定竞争性。     

复合抛物面聚光太阳能PV/T系统的实验研究

设计并搭建了CPC低倍聚光太阳能PV/T单通道空气系统实验台,对不同工作环境下聚光PV/T系统的热电性能进行了实验研究。实验研究结果显示:在聚光条件下,系统的各表面温度随光照强度的增加而升高,随下部通道入口空气流速的增加而降低。聚光PV/T系统的最大输出功率可达到60W,比对应相同电池面积平板系统最大输出功率高20W。聚光PV/T系统的各效率随光照强度增加而增大,系统的最大电效率为11%,最大热效率为70%,最大火用效率为16%,比单纯发电时最大火用效率提高约5%。实验获得了一批新的有价值的实验数据,为聚光太阳能光伏光热系统的进一步研究提供了依据。     

一种基于微热管阵列的太阳能PV/T热泵系统能效实验研究

为了提高PV/T装置的太阳能利用效率,文章提出了一种基于微热管阵列的太阳能PV/T热泵系统,并在恒温供热条件下分析了该系统中PV/T收集器的热、电性能和热泵COP的全天变化趋势,最后将PV/T收集器的电性能与单一光伏发电系统进行对比分析。分析结果表明:在测试时间段内,PV/T收集器的平均热效率为38.7%;PV/T收集器的平均电效率为12%,比单一光伏发电系统提升了27.7%;PV/T收集器的光热光电综合平均效率为70.3%;热泵的平均COP为2.7。     

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。     

太阳电池及光伏热（PV／T）结构的实验研究

设计制作了一个空冷型非晶硅光伏热(PV/T)结构,对太阳电池在天津地区的性能进行了实验研究.在天津地区的太阳辐射情况下,测试的非晶硅太阳电池的电效率约为4.4%,多晶硅太阳电池的电效率约为8.5%.空冷型非晶硅PV/T结构在自然通风冷却作用下,电效率为4.56%,热效率为26.1%,综合能量效率为38.1%;强迫通风冷却作用下电效率为4.61%,热效率为32.8%,综合能量效率为44.9%.     

太阳能光伏光热一体化PV/T组件的实验研究

为提高太阳能的综合利用效率及光伏组件的可靠性,设计并搭建了空气型太阳能光伏光热PV/T组件的实验测试平台,并对常规PV组件和空气型PV/T组件的转化效率进行了实验测试,测试结果表明:以空气为传热介质的PV/T组件在被动循环情况下,组件的板温下降约8℃,比普通PV组件的电效率提高约0.1%,PV/T组件通风后的热效率在25%左右,综合效率最高可达72%。分析结果可为空气型PV/T组件的结构优化和建筑供暖提供参考。     

不同结构PV/T系统散热方式的试验研究

光伏/光热(PV/T)集热器集光伏发电和太阳能低温热利用于一体,既可以提高电池效率,又可以回收和利用低温热能。文章对内置不同冷却结构的PV/T系统和电池板的散热特性进行了对比试验。试验结果表明:回形冷却结构PV/T系统的冷却效果要优于蛇形结构;不同结构PV/T系统的综合效率均大于电池光板的折算综合效率。回形冷却结构的PV/T系统最高综合效率可达40%,而电池板的折算综合效率最高只有14.7%。     

非晶硅PV/T系统的结构方式对性能的影响

以非晶硅PV/T系统为研究对象,对PV/T系统建立传热模型,研究PV/T系统结构改变对其性能的影响.结果表明:非晶硅太阳电池紧贴集热器吸热板时能量效率和(火用)效率均高于电池板作为系统盖板的效率.总体上能量效率和(火用)效率随着太阳辐射强度、工质流量和电池光电转换效率的升高而增加,随着环境风速的增大而减少,但各因素的影响程度随结构方式而异.     

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。     

Exergetic optimization of a solar photovoltaic thermal (PV/T) air collector

In this paper, an exergetic optimization has been developed to determine the optimal performance and design parameters of a solar photovoltaic thermal (PV/T) air collector. A detailed energy and exergy analysis has been carried out to calculate the thermal and electrical parameters, exergy components, and exergy efficiency of a typical PV/T air collector. The thermal and electrical parameters of a PV/T air collector include solar cell temperature, back surface temperature, outlet air temperature, open‐circuit voltage, short‐circuit current, maximum power point voltage, maximum power point current, etc. An improved electrical model has been used to estimate the electrical parameters of a PV/T air collector. Furthermore, a new equation for the exergy efficiency of a PV/T air collector has been derived in terms of design and climatic parameters. A computer simulation program has been also developed to calculate the thermal and electrical parameters of a PV/T air collector. The results of numerical simulation are in good agreement with the experimental measurements noted in the previous literature. Moreover, the simulation results obtained in this paper are more precise than the one given by the previous literature, and the new exergy efficiency obtained in this paper is in good agreement with the one given by the previous literature. Finally, exergetic optimization has been carried out under given climatic, operating, and design parameters. The optimized values of inlet air velocity, duct length, and the maximum exergy efficiency have been found. Parametric studies have been also carried out. Copyright © 2010 John Wiley & Sons, Ltd.     

Optimization of a solar photovoltaic thermal (PV/T) water collector based on exergy concept

In this paper, the optimization of a solar photovoltaic thermal (PV/T) water collector which is based on exergy concept is carried out. Considering energy balance for different components of PV/T collector, we can obtain analytical expressions for thermal parameters (i.e. solar cells temperature, outlet water temperature, useful absorbed heat rate, average water temperature, thermal efficiency, etc.). Thermal analysis of PV/T collector depends on electrical analysis of it; therefore, five-parameter current–voltage (I–V) model is used to obtain electrical parameters (i.e. open-circuit voltage, short-circuit current, voltage and current at the point which has maximum electrical power, electrical efficiency, etc.). In order to obtain exergy efficiency of PV/T collector we need exergy analysis as well as energy analysis. Considering exergy balance for different components of PV/T collector, we obtain the expressions which show the exergy of the different parts of PV/T collector. Some corrections have been done on the above expressions in order to obtain a modified equation for the exergy efficiency of PV/T water collector. A computer simulation program has been developed in order to obtain the amount of thermal and electrical parameters. The simulation results are in good agreement with the experimental data of previous literature. Genetic algorithm (GA) has been used to optimize the exergy efficiency of PV/T water collector. Optimum inlet water velocity and pipe diameter are 0.09 m s⁻¹, 4.8 mm, respectively. Maximum exergy efficiency is 11.36%. Finally, some parametric studies have been done in order to find the effect of climatic parameters on exergy efficiency.     

An improved thermal and electrical model for a solar photovoltaic thermal (PV/T) air collector

In this paper, an attempt is made to investigate the thermal and electrical performance of a solar photovoltaic thermal (PV/T) air collector. A detailed thermal and electrical model is developed to calculate the thermal and electrical parameters of a typical PV/T air collector. The thermal and electrical parameters of a PV/T air collector include solar cell temperature, back surface temperature, outlet air temperature, open-circuit voltage, short-circuit current, maximum power point voltage, maximum power point current, etc. Some corrections are done on heat loss coefficients in order to improve the thermal model of a PV/T air collector. A better electrical model is used to increase the calculations precision of PV/T air collector electrical parameters. Unlike the conventional electrical models used in the previous literature, the electrical model presented in this paper can estimate the electrical parameters of a PV/T air collector such as open-circuit voltage, short-circuit current, maximum power point voltage, and maximum power point current. Further, an analytical expression for the overall energy efficiency of a PV/T air collector is derived in terms of thermal, electrical, design and climatic parameters. A computer simulation program is developed in order to calculate the thermal and electrical parameters of a PV/T air collector. The results of numerical simulation are in good agreement with the experimental measurements noted in the previous literature. Finally, parametric studies have been carried out. Since some corrections have been down on thermal and electrical models, it is observed that the thermal and electrical simulation results obtained in this paper is more precise than the one given by the previous literature. It is also found that the thermal efficiency, electrical efficiency and overall energy efficiency of PV/T air collector is about 17.18%, 10.01% and 45%, respectively, for a sample climatic, operating and design parameters.     

一种新型全铝扁盒式PV/T热水系统

将单晶硅光伏电池与全铝扁盒式太阳能热水器集热板通过特殊工艺粘结起来,制成了一套自然循环式光伏光热一体化(PV/T)系统,在利用太阳能发电的同时提供热水。于04年7月-10月在合肥地区进行了室外实验,测试并讨论了该系统以不同水量和不同初始水温运行时的光电光热性能。结果表明,当m/Ac>80kg/m2时,这种PV/T热水系统的发电效率在10.15%左右,热效率在50%左右,光电光热总效率可以达到60%左右,光电光热综合性能效率可以达到70%左右。相对于单纯的光伏系统或自然循环式太阳能热水系统,这种PV/T热水系统具有占地面积小、综合效率高等优点。     

Design considerations for flat-plate-photovoltaic/thermal collectors

Several potentially useful features in the design of photovoltaic/thermal (PV/T) collectors are explored in order to determine their effectiveness and interaction. Based on a computer simulation of flat-plate PV/T collectors that is applicable to a wide range of designs, the present work focuses on air-type collectors employing single crystal silicon PV cells. Features explored center on two main areas: increasing the solar absorptance and reducing the infrared emittance. The results of the simulations can be summarized as follows: for PV cells covering greater than approximately 65% of the total collector area, a selective absorber actually reduces the thermal efficiency when used with a gridded-back cell. The requirements for the low emissivity coating are an infrared emissivity of less than 0.25 and a solar transmissivity of greater than 0.85. The optimum combination for an air PV/T was found to consist of gridded-back PV cells, a nonselective secondary absorber, and a high-trans-missivity/low-emissivity cover above the PV cells.     

Design concept and mathematical model of a bi-fluid photovoltaic/thermal (PV/T) solar collector

This paper presents an improved design of a photovoltaic/thermal (PV/T) solar collector integrating a PV panel with a serpentine-shaped copper tube as the water heating component and a single pass air channel as the air heating component. In addition to the electricity generated, this type of collector enables the production of both hot air and water, increasing the total efficiency per unit area compared to the conventional PV/T solar collector. The use of both fluids (bi-fluid) also creates a greater range of thermal applications and offers options in which hot and/or cold air and/or water can be utilized depending on the energy needs and applications. In this paper, the design concept of the bi-fluid PV/T solar collector is emphasized with 2D steady state energy balance equations for the bi-fluid configuration are developed, validated and used to predict the performance of the bi-fluid solar collector for a range of mass flow rates of air and water. The performance of the collector is then compared when the fluids are operated independently and simultaneously. The simulations indicate that when both fluids are operated independently the overall thermal and electrical performance of the solar collector is considered as satisfactory and when operated simultaneously the overall performance is higher. The bi-fluid PV/T solar collector discussed in this paper will add insights to the new knowledge of optimizing the utilization of solar energy by a PV/T solar collector and has potential applications in various fields.     

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.     

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.     

A critical review of photovoltaic–thermal solar collectors for air heating

Integrated photovoltaic–thermal solar collectors have become of great interest in the solar thermal and photovoltaic (PV) research communities. Solar thermal systems and solar PV systems have each advanced markedly, and combining the two technologies provides the opportunity for increased efficiency and expanded utilization of solar energy. In this article, the authors critically review photovoltaic–thermal solar collectors for air heating. Included is a review of photovoltaic thermal technology and recent advances, particularly as applied to air heaters. It is determined that the photovoltaic–thermal (PV/T) air heater is or may in the future be practicable for preheating air for many applications, including space heating and drying, and that integrated PV/T collectors deliver more useful energy per unit collector area than separate PV and thermal systems. Although PV/T collectors are promising, it is evident that further research is required to improve efficiency, reduce costs and resolve several technical design issues related to the collectors.