A New Dynamic and Vertical Photovoltaic Integrated Building Envelope for High-Rise Glaze-Facade Buildings

Substantially glazed facades are extensively used in contemporary high-rise buildings to achieve attractive architectural aesthetics.Inherent conflicts exist among architectural aesthetics,building energy consumption,and solar energy harvesting for glazed facades.In this study,we addressed these conflicts by introducing a new dynamic and vertical photovoltaic integrated building envelope(dvPVBE)that offers extraordinary flexibility with weather-responsive slat angles and blind positions,superior architectural aesthetics,and notable energy-saving potential.Three hierarchical control strategies were proposed for different scenarios of the dvPVBE:power generation priority(PGP),natural daylight priority(NDP),and energy-saving priority(ESP).Moreover,the PGP and ESP strategies were further analyzed in the simulation of a dvPVBE.An office room integrated with a dvPVBE was modeled using EnergyPlus.The influence of the dvPVBE in improving the building energy efficiency and corresponding optimal slat angles was investigated under the PGP and ESP control strategies.The results indicate that the application of dvPVBEs in Beijing can provide up to 131%of the annual energy demand of office rooms and significantly increase the annual net energy output by at least 226%compared with static photovoltaic(PV)blinds.The concept of this novel dvPVBE offers a viable approach by which the thermal load,daylight penetration,and energy generation can be effectively regulated.

Progress of semitransparent emerging photovoltaics for building integrated applications

With the rapid development of emerging photovoltaics technology in recent years,the application of building-integrated photovoltaics(BIPVs)has attracted the research interest of photovoltaic communities.To meet the practical application requirements of BIPVs,in addition to the evaluation indicator of power conversion efficiency(PCE),other key performance indicators such as heat-insulating ability,average visible light transmittance(AVT),color properties,and integrability are equally important.The traditional Si-based photovoltaic technology is typically limited by its opaque properties for application scenarios where transparency is required.The emerging PV technologies,such as organic and perovskite photovoltaics are promising candidates for BIPV applications,owing to their advantages such as high PCE,high AVT,and tunable properties.At present,the PCE of semitransparent perovskite solar cells(ST-PSCs)has attained 14%with AVT of 22–25%;for semitransparent organic solar cells(ST-OSCs),the PCE reached 13%with AVT of almost 40%.In this review article,we summarize recent advances in material selection,optical engineering,and device architecture design for high-performance semitransparent emerging PV devices,and discuss the application of optical modeling,as well as the challenges of commercializing these semitransparent solar cells for building-integrated applications.

Building Integrated Photovoltaic Systems for Single Family Dwellings: Innovation Concepts

Growing consumer interest in distributed Building Integrated Photovoltaic (BIPV) Systems and industry competition to reduce installation costs are stimulating the development of deploying these materials to the residential sector of the building industry. This emerging market continues to attract the attention of many stakeholders, yet cohesive opportunities to deploy in residential sectors, specifically detached single-family dwellings, is scattered. As a result, this study of literature and implementation strategies through simple examples looks to identify several characteristics related to BIPV. Characteristics that were studied in this initial pilot study were design considerations for system selection, applicability to residential construction, and system and material options and enhancements. A case-study home was analyzed demonstrating opportunity for implementation of BIPV on an existing residence. Strategies for maximizing the energy-generating capacity of the system to achieve net-zero energy performance, including all building surfaces and landscaping were also explored. This body of work provides a state-of-the-art review on common materials as well as the more customizable types.

Research on Key Technologies of Solar Photovoltaic Building Integration

On December 21,2020,The State Council Information Office issued a white paper titled"China's Energy Development in the New Era,"in which the installed capacity of hydropower,wind power,photovoltaic power and biomass power generation in China ranked first in the world[1].Solar photovoltaic power generation is the most important development direction of clean energy in the world.It is an important energy strategy to combine it with the field of construction in China.This paper mainly introduces the characteristics and problems of the key technologies of solar photovoltaic building integration,and explores its future development direction and ways,in order to constantly promote the industrialization of new energy technology in China.

Design and performance testing of a novel building integrated photovoltaic thermal roofing panel

A novel building integrated photovoltaic thermal(BIPVT)roofing panel has been designed considering both solar energy harvesting efficiency and thermal performance.The thermal system reduces the operating temperature of the cells by means of a hydronic loop integrated into the backside of the panel,thus resulting in maintaining the efficiency of the solar panels at their feasible peak while also harvesting the generated heat for use in the building.The performance of the proposed system has been evaluated using physical experiments by conducting case studies to investigate the energy harvesting efficiency,thermal performance of the panel,and temperature differences of inlet/outlet working liquid with various liquid flow rates.The physical experiments have been simulated by coupling the finite element method(FEM)and finite volume method(FVM)for heat and mass transfer in the operation.Results show that the thermal system successfully reduced the surface temperature of the solar module from 88℃to as low as 55℃.Accordingly,the output power that has been decreased from 14.89 W to 10.69 W can be restored by 30.2%to achieve 13.92 W.On the other hand,the outlet water from this hydronic system reaches 45.4℃which can be used to partially heat domestic water use.Overall,this system provides a versatile framework for the design and optimization of the BIPVT systems.

URBAN PHOTOVOLTAIC POTENTIAL OF INCLINED ROOFING FOR BUILDINGS IN HERITAGE CENTERS IN EQUATORIAL AREAS

In situ renewable energy production is a favourable alternative for reducing pollu-tion and combating climate change.The research area,Cuenca,Ecuador,is located in the Andes near the equator with optimal conditions for energy self-supply due to its low energy demands and low levels of irradiation variability.In this study,tem-porary fluctuations in consumption based on 2016 electricity consumption data are characterized.Using GIS,available roofing polygons are obtained,and the amount of usable solar radiation is estimated based on these values.With available surface,orientation,and inclination information,electricity generation based on photovoltaic performance is estimated and compared for monocrystalline silica panels and pho-tovoltaic solar roof tiles,which are architectural alternatives.A potential net supply of 148%is found for monocrystalline silica photovoltaic panels in a typical format,whereas that of photovoltaic tiles is only 61%.In addition,production-demand imbalances are predicted in extreme months and average months and on extreme days due to variations in irradiation and demands.

Adoption of wide-bandgap microcrystalline silicon oxide and dual buffers for semitransparent solar cells in building-integrated photovoltaic window system

We focused on developing penetration-type semitransparent thin-film solar cells(STSCs) using hydrogenated amorphous Si(a-Si:H) for a building-integrated photovoltaic(BIPV) window system. Instead of conventional p-type a-Si:H, p-type hydrogenated microcrystalline Si oxide(p-μc-SiOx:H) was introduced for a wide-bandgap and conductive window layer. For these purposes, we tuned the CO2/SiH4 flow ratio(R) during p-μc-SiOx:H deposition. The film crystallinity decreased from 50% to 13% as R increased from 0.2 to 1.2. At the optimized R of 0.6, the quantum efficiency was improved under short wavelengths by the suppression of p-type layer parasitic absorption. The series resistance was well controlled to avoid fill factor loss at R = 0.6. Furthermore, we introduced dual buffers comprising p-a-SiOx:H/i-a-Si:H at the p/i interface to alleviate interfacial energy-band mismatch. The a-Si:H STSCs with the suggested window and dual buffers showed improvements in transmittance and efficiency from 22.9% to 29.3% and from 4.62% to 6.41%, respectively, compared to the STSC using a pristine p-a-Si:H window.

A maximum power point tracking strategy applied to building integrated photovoltaics

To solve the problem of permanent-shadow shading of photovoltaic buildings,a maximum power point tracking(MPPT)strategy to determine the search range by pre-delimiting area is proposed to improve MPPT efficiency.The single correspondence between the solar-cell current-voltage(I-V)curve and the illumination conditions was proved by using the single-diode model of photovoltaic cells,thus proving that a change in the illumination conditions corresponds to a unique maximum power point(MPP)search area.According to the approximate relationship between MPP voltage,current and open-circuit voltage and short-circuit current of a photovoltaic module,the voltage region where the MPP is located is determined and the global maximum power point is determined using the power operating triangle strategy in this region.Simulation carried out in MATLAB proves the correctness and feasibility of the theoretical research.Simulation results show that the MPPT strategy proposed in this paper can improve the average efficiency by 1.125%when applied in series as building integrated photovoltaics.

冰上运动建筑曲面光伏参数化集成设计研究

2022年冬奥会成功举办,国内掀起了冰上体育运动的热潮,冰上运动建筑需求量和能源消耗量随之增长。光伏建筑一体化(Building Integrated Photovoltaic,BIPV)作为建筑节能的主要手段之一,在体育建筑屋面具有较大的集成潜力。通过建立寒冷地区曲面冰上运动建筑典型模型进行集成设计研究,基于Grasshopper参数化平台实现新型柔性CIGS薄膜光伏组件沿屋面曲线形态的优化布置,从两个层级出发,提出参数化设计方法与构造措施。通过Honeybee进行能耗模拟,结果表明,该柔性光伏系统全年可以为冰上运动建筑降低15.82%的能量消耗,进而验证了该方案的节能性,为建筑师进行寒冷地区曲面冰上运动建筑设计的节能优化设计提供数据支撑及科学依据。

光伏光热联合双源热泵系统运行模式研究(2):供暖季系统仿真研究

使用TRNSYS软件建立了光伏光热-双源热泵(PV/T-DSHP)系统的仿真模型。选取夏热冬冷地区某一近零能耗居住建筑作为研究对象,模拟研究了供暖季PV/T-DSHP系统在COP_(s)切换模式下的运行特性和能耗。结果表明:平均光电效率为15.08%,平均光热效率为33.05%;水源热泵运行模式下供暖季平均COP为4.55,空气源热泵运行模式下供暖季平均COP为3.19,PV/T-DSHP系统的平均COP_(s)为2.98;供暖季系统自满足率为61%。

考虑建筑物热惯性的综合能源系统主从博弈协调优化策略

从用户角度出发,提出一种考虑建筑物热惯性的综合能源系统主从博弈协调优化策略。首先,建立热网特性模型和建筑物热惯性模型,并构建以微网运营商为领导者,用户为跟随者的主从博弈数学模型。在光伏出力大时,用户通过电制热设备将电能转化为热能,并利用建筑物热惯性将热能加以存储,无需将光伏余电尽数售给微网运营商,可增强用户权益,同时可有效避免大量光伏余电接入电网,进而缓和余电上网的压力。其次,考虑用户用能满意度及温度舒适度,建立微网运营商与用户的定价、定量模型,并证明Stackelberg博弈均衡解的存在性与唯一性。最后通过算例验证所提策略的有效性,极大地增强了用户权益,同时避免用户光伏余电大量接入电网。

光伏光热一体化建筑热负荷能效分层调度仿真

光伏光热一体化系统中涉及多种能源,包括太阳能和热能等。由于不同能源的产生、存储和使用特性不同,加之系统内部的复杂性,使得实现多能源协同调度变得复杂。为了获取满意的建筑热负荷能效分层协同调度结果,提出一种光伏光热一体化建筑热负荷能效分层协同调度方法。研究光伏光热一体化建筑中热负荷的热量传递过程,对热负荷自身和热惯性展开分析,获取热负荷热惯性大小和室内热量需求两者的关系。以最大[火用]效率和最小调度成本为目标,分别建立光伏光热一体化建筑热负荷能效上层和下层协同调度模型。通过量子粒子群算法对模型展开分析计算,确定最优建筑热负荷能效分层协同调度方案。实验分析表明,所提方法的热负荷能效分层协同调度效果好,且节能效益高。

寒冷地区光伏墙体综合传热特性的数值模拟研究

近年来BIPV项目逐渐增多,对光伏墙体的研究多以光伏组件电热性能为重点,少有结合节能墙体热工性能对不同构造光伏墙体的综合传热特性优化开展的研究。以天津地区为应用场景,分别建立符合天津市居住建筑四步节能设计技术指标的基础墙体、普通光伏墙体和嵌入保温隔热一体化板的新型光伏墙体的传热模型,采用ANSYS FLUENT软件对其温度分布、表面热流密度进行数值模拟,对模拟结果进一步分析获得不同类型墙体的传热系数和光伏组件的电性能。结果表明:较基础墙体,夏季普通光伏墙体内表面得热量可增加46.88%,冬季普通光伏墙体内表面失热量可减少5.47%;新型光伏墙体中的保温隔热层厚度宜不小于20 mm,此时,夏季新型光伏墙体内表面得热量最大可增加18.16%,冬季新型光伏墙体内表面失热量最小可减少20.07%。基于计算结果,寒冷地区的建筑外墙应用光伏组件时,散热构造措施可简化。

绿色金融支持我国东部地区BIPV建筑发展评价及耦合分析

以我国东部地区的10个省(市)为例,建立2017-2021年绿色金融和光伏建筑一体化(BIPV)发展的评价指标体系,并利用熵值法与耦合协调度模型开展实证分析。研究结果表明:从区域性发展差异上看,绿色金融发展和BIPV建筑发展水平较高的是上海市和北京市,相对落后的是河北省和海南省;从发展态势上看,绿色金融和BIPV建筑发展总体上呈上升趋势;从耦合特征上看,近年来我国东部地区绿色金融和BIPV建筑发展两系统之间的耦合度及耦合协调度均较高,且总体呈逐步增长的趋势。

基于MPC的光电热联合系统建模与控制优化

为解决我国北方地区冬季采暖产生的能源消耗与环境污染问题,改善光资源丰富、较丰富地区光能利用率不足的现状,充分利用谷电和日照优势,针对太阳能利用与建筑采暖相结合的分布式能源系统性问题,提出一种基于TRNSYS动态建模与数值建模相结合的光电热联合供暖系统。综合考虑小范围内供暖温度的时滞性以及系统各设备的出力情况,联合Matlab搭建模型预测控制器(MPC),提出一种基于MPC的误差实时校正优化控制策略。分析表明:采用MPC的控制优化,在热负荷跟踪方面,最大误差降低4.16%,平均误差降低2.79%;在室内温度控制方面,最大偏差降低1.2℃,平均偏差降低0.2℃;在太阳能利用占比方面,太阳辐射强度趋近于800 W/m^(2)时,太阳能利用占比差距达最大8.9%。分析结果说明该系统可以更快速、更准确地跟踪建筑热负荷波动,并且有效抑制室内温度波动,提高清洁能源的利用率。

BIPV/T–DSF与新风一体化系统性能模拟研究

为提高光伏光热建筑一体化技术中光伏组件发电效率,充分利用其光热能量,同时满足室内人员对新风的需求,本研究将光伏光热建筑一体化技术与双层皮玻璃幕墙相结合,组成BIPV/T–DSF与新风一体化系统。以沈阳市一间30 m2的卧室为研究对象,通过实地测量室内污染物浓度并进行系统仿真模拟,对室内空气质量状况进行评估,并对系统的热电性能、空气通道内流场的流动特性进行研究。结果表明:系统运行时,冬季热效率达到0.22,电效率达到0.178;夏季电效率由原来的0.151提高到0.156。新风对于室内甲醛浓度有较好的净化效果,系统通风运行20 min后,甲醛浓度即可稳定在0.033 mg/m3。

光伏建筑一体化光伏幕墙体系与经济性研究

在当今全球能源转型的大背景下,建筑行业作为主要能源消费领域,其能源消费模式的革新对于实现国家层面的可持续发展目标至关重要。鉴于此,显著削减建筑领域对化石燃料的依赖,并积极拓宽可再生能源的利用渠道,成为了推动绿色建筑革命的重要策略。光伏建筑一体化(BIPV)技术,作为一种将高效光伏发电系统与现代化建筑设计、建造工艺深度融合的创新实践,不仅展现了太阳能这一清洁、可再生资源的巨大应用潜力,而且也预示着未来建筑领域在能源自给自足方面广阔的发展蓝图。为了探究光伏建筑一体化的现状,文章对光伏建筑一体化的背景及常用的应用场景进行研究,通过案例分析光伏幕墙增量成本,并采用静态投资回收期和效益费用比两个参数对薄膜类光伏幕墙、晶硅类光伏幕墙、薄膜类光伏采光顶三种光伏方案的经济性进行分析,为后续光伏建筑一体化中光伏幕墙的经济性提供参考。

外显、灵活、多维、高效——从2022中国国际太阳能十项全能竞赛看建筑与光伏一体化设计趋势

建筑光伏一体化技术是实现建筑行业节能减碳的重要途径。以第三届中国国际太阳能十项全能竞赛(SDC2022)为例,对15个参赛作品在建筑与光伏一体化设计上的特征进行了比较,从美学表现、构造整合、功能复合、性能提升4个维度分析了当前建筑与光伏一体化的设计新趋势,指出:在美学表现上,通过光伏组件材质外观和光伏方阵形成积极外显的形态;在构造上,采用不同类型光伏灵活组合衍生多种应用场景;在功能上,将光伏发电与建筑围护结构的采光、集热、遮阳、防护等功能进行多维度复合;在性能上,通过光伏朝向与倾角、散热设计和电气系统综合提升产能效率。为建筑与光伏一体化技术的推广和应用提供新思路。

以光伏集成性能为导向的建筑形体生成方法——基于参数化与形状语法的实现

光伏技术的应用对减少能源消耗、降低能源成本、减少碳排放和实现可持续发展都具有巨大潜力,是推动可持续能源未来的关键技术之一。提出了一种以单位体积太阳辐射、建筑体形系数和能源覆盖率为性能指标,通过形状语法的参数化编译使之符合形状语法规则的光伏建筑一体化(BIPV)建筑形态生成方法。通过建筑形体生成实验表明,该方法在给定的简单初始形状基础上经过25代迭代计算均可生成一定数量且具有显著差异的建筑形体最优解集。可以根据特定性能对建筑形体的最优解进行排序为设计提供选择,也可以根据建筑密度或总建筑面积等的设计要求进行筛选。同时实验发现初始形状对建筑形体的性能有显著的影响。实验显示本方法可以作为以太阳能辐射性能为导向的形体生成方法应用于早期设计阶段。