结合光伏光热组件的双源热泵系统的研究

考虑到太阳能电池板温度升高时其光电转换效率降低,以及水源温度升高时热泵运行效率增加的特点,设计出一套结合光伏光热(PV/T)组件的双源热泵系统。对该系统进行室外实际运行实验,通过实验验证系统是否能够稳定运行,并验证太阳能电池板降温提效的可行性。实验结果表明,该系统运行可靠,且组件电池转换效率与固定倾角的追踪式光伏(TPV)组件相比,提高0.3%左右,能够为下一步研究最优运行方式提供实验数据支持。     

太阳能光伏光热(PV/T)热泵热水系统实验研究

本文搭建了1种间接式基于太阳能光伏光热(PV/T)部件的热泵热水系统应用示范平台,其中PV/T集热器面积为64 m~2。对PV/T热泵系统在不同环境温度和辐照条件下的光电光热性能进行了测试分析,结果表明PV/T部件发电量较之传统光伏组件提高11.0%,PV/T电池温度比较传统光伏组件温度平均降温25.5℃,可以有效缓解较高温度对光伏电池使用寿命的影响。热泵机组平均COP可达4.7。PV/T热泵系统的光伏光热综合效率可达74.4%,在产热发电性能上与传统集热器和光伏组件更有优势。在将3 m~3水从31.0℃加热至51.0℃的过程中,PV/T热泵系统总发电量和耗电量分别为28.0 kW·h和24.5 kW·h,并且夏季晴朗少云条件下,发电功率一直高于用电功率,可以实现离网使用。     

新型光伏光热幕墙组件性能特性研究

将微热管阵列技术引入传统光伏幕墙,组成新型光伏光热幕墙组件(Micro Heat Pipe Array-Building Integrated Photovoltaic,MHPA-BIPV/T),再应用到光伏光热系统中。通过实验对新型光伏光热幕墙组件与传统的光伏幕墙组件、透光型PV/T幕墙组件和非透光型PV/T幕墙组件作对比,结果表明新型PV/T幕墙组件比传统PV幕墙组件光电转换效率提升较为显著,其中,透光PV/T组件比透光PV组件的日平均光电转换效率提升了9%,非透光PV/T组件比非透光PV组件的日平均光电转换效率提升了4%;透光PV/T幕墙组件的日平均总效率为51%,非透光PV/T幕墙组件的日平均总效率为46%。     

光伏建筑装饰一体化铝型材基板的水冷系统

研究发现光伏组件模块的发电效率会随着其工作温度的升高急剧下降。而目前的光伏建筑一体化系统中,由于使用导热性能较差的玻璃作为基底和光伏构件没有进行主动散热降温的原因,导致构件内部的光伏组件模块温度很高,太阳能电池效率仅能达到8%~9%。利用一种中空的铝质型材作为光伏构件的基底,并通入介质水使光伏组件模块在得到主动冷却条件下,工作温度大幅降低,可使太阳能电池的效率提高约40%。通过这种主动降温方式能够使光伏建筑一体化发电系统的效能得到有效提升。     

太阳能光伏光热组件(PV/T)性能评价方法研究

结合对某太阳能光伏光热组件(PV/T)的测试数据,从热力学第一定律、热力学第二定律、发电效率和集热效率的角度对PV/T组件的性能进行了评价,对评价结果进行了分析,给出了PV/T组件性能评价方法。     

大型并网光伏电站电池组件自动水清洗系统

光伏电站在节能减排、减少大气污染做出了贡献，但是大型并网光伏电站电池组件清洗一直是电站经营管理人员比较头疼的问题。目前光伏组件表面清洗基本靠人工完成，效率低下，成本较高，如不及时清洗，又影响发电量。本文提出水清洗系统，实现光伏电站电池组件清洗工作高效和环保。     

水冷型PV/T系统的高效利用与发展现状

在光伏光热系统(PV/T)中为提高其电效率并高效利用低品位热能,近年来对于冷却工质及其工作方式的研究越来越多。其中,水冷式以其方便直接使用、无需二次换热、良好的光学特性和高热容量等优点,受到了广泛的理论研究和实验测试。通过以效率的视角探究光伏覆盖率、背管分布形式等影响流体冷却能力的因素,并结合相变PV/T、PV/T矩阵等PV/T未来发展新趋势,为今后水冷型PV/T系统进一步高效实验提供了研究方向。     

科技动态

正力诺光伏太阳能多晶电池片效率达到17.81%2013年11月27日,力诺光伏集团电池二厂批量生产多晶电池片转换效率达到17.81%,与前期最高效率相比提高0.2%,提前一个多月完成年度效率指标。通过对本批次电池片后续封装组件的跟踪发现,260W以上组件占比达到15%,降低了营销接单门槛,为开拓高功率组件市场奠定了基础。提高电池转换效率是迎接市场挑战的     

玻璃盖板与光伏板间距对PV/T系统性能的影响

通过对PV/T系统中的光伏板和玻璃盖板进行热平衡分析,探讨光伏板与玻璃盖板之间的板间距对PV/T系统光热效率的影响。根据天津地区典型年气象参数,计算出在不同的板间距不同光伏板温度的情况下,PV/T系统中光伏板散热量和光热效率,对计算结果进行分析。随着板间距变大,PV/T系统的光热效率开始快速升高,达到极大值后随着板间距继续增加,光热效率有所下降,下降到一定程度后又有所上升。PV/T系统中光伏板散热量的变化趋势与此相反。对所分析的两种光伏板温度(40℃、50℃),最佳板间距随着光伏板温度的升高而减小。当光伏板的温度控制在40℃时最佳板间距为6 cm,当光伏板的温度控制在50℃时最佳板间距为5 cm。由于调节板间距容易实现,所以选择合适的板间距对提高PV/T系统的光热效率有实用价值。     

太阳能建筑光伏/热电系统(PV/TV)性能研究

本文将太阳能电池板、集热器、热电发电片结合起来,设计并开发制成了一套光伏/热电系统(PV/TV),在利用太阳能电池发电的同时,可将热量收集并利用其发电。而后将这种系统在北京地区进行了室外模拟实验,测试并讨论了该系统在4～10月的发电性能,对PV/TV系统在光伏建筑中的应用进行了初步探讨。结果表明,相对于单纯的光伏发电系统,PV/TV系统单位面积发电效率有5%～15%的提高。     

深圳T3航站楼雨水池应用于空调冷却系统的研究

针对深圳即将建设的T3航站楼,对雨水池能否用于空调冷却系统进行了研究。结果表明,在深圳地区地表水间接应用于空调冷却系统是不节能的,采用处理后的雨水作为冷却水系统补水,节水省钱效果显著。     

建筑一体化电热冷联产光伏组件能量特性研究

传统太阳能光伏或光热建筑一体化只能为建筑提供单一电能或热能。通过研究一种集成发电、集热、制冷3种功能的建筑一体化电热冷联产光伏组件,对其夏季工况下能量特性进行了实际检测。结果表明:白天,组件集热同时能有效降低光伏电池温度,组件工作温度高于环境温度约8~16℃,发电和集热效率分别为14.1%~13.7%和40.1%~15.7%;晴朗夜间,组件通过对流和辐射两种传热方式进行散热制冷,总制冷功率为26.0~268.5 W/m~2。电热冷联产光伏组件适合与热泵结合,为建筑提供所需能源。     

Efficiency characteristic of building integrated photovoltaics as a shading device

A building-integrated photovoltaic system (BIPV) has been operated over 1 year in the Samsung Institute of Engineering & Construction Technology (SIECT) in Korea. The PV cells are mounted on the south facade and on the roof of the SIECT in the Giheung area. Special care was taken in the building design to have the PV modules shade the building in the summer, so as to reduce cooling loads, while at the same time allowing solar energy to enter the building during the heating season, and providing daylight. This paper gives a 1 year analysis of the system performance, evaluation of the system efficiency and the power output, taking into account the weather conditions. As a part of certain design compromises, that took into account, aesthetic, safety, and cost considerations, non-optimal tilt angles and occasional shading of the PV modules made the efficiency of PV system lower than the peak rating of the cells. The yearly average efficiency of the sunshade solar panel is 9.2% (average over 28.6°C surface temperature), with a minimum of 3.6% (average over 27.9°C surface temperature) in June and a maximum of 20.2% (average over 19.5°C surface temperature) in December.     

A heat pipe photovoltaic/thermal (PV/T) hybrid system and its performance evaluation

Building-integrated photovoltaic/thermal (BIPV/T) system has been considered as an attractive technology for building integration. The main part of a BIPV/T system is PV/T collector. In order to solve the non-uniform cooling of solar PV cells and control the operating temperature of solar PV cells conveniently, a heat pipe photovoltaic/thermal (PV/T) hybrid system (collector) has been proposed and described by selecting a wick heat pipe to absorb isothermally the excessive heat from solar PV cells. A theoretical model in terms of heat transfer process analysis in PV module panel and introducing the effectiveness-number of transfer unit (?-NTU) method in heat exchanger design was developed to predict the overall thermal-electrical conversion performances of the heat pipe PV/T system. A detailed parametric investigation by varying relevant parameters, i.e., inlet water temperature, water mass flow rate, packing factor of solar cell and heat loss coefficient has been carried out on the basis of the first and second laws of thermodynamics. Results show that the overall thermal, electrical and exergy efficiencies of the heat pipe PV/T hybrid system corresponding to 63.65%, 8.45% and 10.26%, respectively can be achieved under the operating conditions presented in this paper. The varying range of operating temperature for solar cell on the absorber plate is less than 2.5 °C. The heat pipe PV/T hybrid system is viable and exhibits the potential and competitiveness over the other conventional BIPV/T systems.     

Study of the performance of thermoelectric modules for use in active building envelopes

Active building envelope (ABE) systems are a new enclosure technology which integrate photovoltaic (PV) and thermoelectric (TE) technologies. In ABE systems, a PV system supplies electrical power to a TE heat-pump system, which can transfer heat in one direction or another depending on the direction of the current. Both the TE and PV systems are integrated into one enclosure surface. Hence, ABE systems have the ability to actively control the flow of heat across their surface when exposed to solar radiation. Applications for this technology include all types of enclosures that require cooling or heating, such as building enclosures. At this stage of our study, we are developing various ABE system prototypes by using commercially available PV and TE technologies. In this study, two types of commercial available TE modules are studied for their potential application in an ABE prototype window system. We have performed various experiments to determine the coefficient of performance for these TE modules when operating under different voltage regimes, and have tested different electrical connection diagrams. Based upon the measured data, and results based on the computational models of a TE system, the most suitable type of TE modules, the voltage and current, and the preferable connection diagrams are discussed.     

Evaluating the low exergy of chilled water in a radiant cooling system

In this paper, in order to make guidelines for designing a low-energy radiant cooling system with an air-handling unit (AHU) for dehumidification, we investigated the impact of various air-conditioning parameters on the exergies of chilled water supplied to radiant panels and a cooling coil. The cooling load, thermal comfort index PMV, relative humidity, area of radiant panels, sensible heat factor (SHF), temperature and air-flow rate of supply air of the AHU, and presence/absence of total heat exchanger were considered. We used computational fluid dynamics (CFD) code in order to analyze the indoor air-flow and thermal environments, and added models for the calculation of thermal transfer to radiant panels and a cooling coil. Furthermore, a feedback control algorithm was introduced to calculate the surface radiant panel temperature, targeting the average PMV of the task area in an office room. As a result, the impact of various air-conditioning parameters on the exergies of chilled water were demonstrated quantitatively. As an example, by reducing the cooling load rate from 100% to 57% and 27%, the exergy of chilled water decreased by 47% and 67%, respectively.     

Field performance of a Japanese low energy home relying on renewable energy

This paper describes the construction and evaluation of an experimental low energy home assisted by a hybrid system using natural energy resources and unused energy. The home, for which a ground source heat pump (GSHP) system has been installed, was built on the campus of Hokkaido University, Japan in March 1997. The total floor area of the home is 192 m². This home is super insulated and airtight; the calculated coefficient of heat loss is 0.97 W/m² K. It has various passive strategies including direct solar heat gain and a ventilation system with an exhaust stack. Photovoltaic (PV) modules, wind power and solar collectors are adopted in order to achieve self-sufficiency in electric power and domestic hot water (DHW) supply. A GSHP is used for space heating and cooling. Two vertical steel wells are used as vertical earth heat exchangers (VHE). In summer, there is a floor cooling system using piped cold water from the VHE.Approximately 80% of the home’s total energy was provided by PV modules, solar collectors, as well as underground and exhaust heat. The annual amount of purchased energy during the test period was 12.5% that of a typical home in Hokkaido.     

空调冷却水系统设计中几个问题的分析

分析了仅夏季用的空调冷却水系统不设循环水箱（水池）时冷却塔集水槽所需的只及系统运行的可靠性。给出了冷却水系统的合理补水量，讨论了冷却水系统应采用的合理水处理方式。     

空调系统冷却塔集水槽的最小容积及补水量

给出了当冷却水系统不设循环水池时空调系统冷却塔集水槽的最小容积,指出了为保证冷却水系统稳定可靠的运行应采取的措施,讨论了冷却塔水损失的组成,提出了冷却塔的合理补水量．     

自然冷却下太阳能PV板发电效率的影响研究

基于一维稳态传热模型,通过数值模拟与计算,进行了自然冷却条件下散热肋片对PV板发电效率的影响研究,对不同因素包括PV板水平倾角、空气温度、风速和肋片高度等对PV板发电效率的影响进行了研究,研究结果对于PV板被动式冷却设计具有一定的实际意义和参考价值。