南京地区某办公建筑南向水平外遮阳角度节能研究

本文利用eQUEST软件对南京某办公建筑南向水平外遮阳板倾斜角度进行了研究,分析了不同外遮阳板倾斜角度对建筑节能效果的影响规律,指出当建筑南向采用水平固定外遮阳板时,遮阳板应尽量向下倾斜安装,倾斜角度以45°之内为宜；倾斜角度在45 °之内的活动遮阳板更能显示出其相对于固定式遮阳板的优势.     

夏热冬冷地区窗户遮阳系统的综合能效研究

为了比较夏热冬冷地区常见窗户遮阳系统的综合能效,本文以长沙地区典型住宅建筑为例,利用Energy Plus建立模型,对光伏遮阳以及蜂巢帘、固定遮阳篷、卷帘、水平百叶窗帘等传统遮阳系统进行综合能效研究。研究内容包括光伏遮阳系统在不同方位角和不同倾斜角下的净能耗,以及其它4种传统遮阳系统在不同品质和不同布置方式下的总能耗,最后对光伏遮阳系统与传统遮阳系统的节能效果进行了比较分析。研究结果表明:南向光伏遮阳系统最佳安装角度为30°,东西向光伏遮阳系统最佳安装角度在35°到45°之间;传统遮阳系统中,蜂巢帘和卷帘节能效果最好,相比于无遮阳条件可实现节能20%以上;此外,光伏遮阳系统相比于最优的传统遮阳系统至少可以节能30%。     

基于SciLab/Xcos的太阳能光伏建筑节能效果仿真分析

根据太阳能电池特点,建立基于试验数据的太阳能光伏建筑发电量计算方法;依据建立的计算方法,采用开源软件SciLab/Xcos建立太阳能光伏建筑节能评价动态仿真模型,并对沈阳地区某建筑进行仿真分析。结果表明,固定安装光伏系统时,若安装倾角为36°则能取得最佳电量输出;屋顶单位面积年平均发电量为76 kW·h/m~2;增加墙面、遮阳处光伏系统能显著增加节能总量,但单位面积发电量及利用率相应降低。     

建筑遮阳对建筑空调采暖能耗的影响分析

针对建筑遮阳对建筑能耗的影响问题,以数值模拟为研究手段,选取具有代表性的建筑南向水平遮阳进行研究,采用控制变量法分别分析不同气候区的不同窗墙比、不同窗户类型、不同遮阳板长度对建筑空调采暖能耗的影响,得到了五个气候区建筑南向窗墙比、窗户遮阳系数和水平遮阳板长度对建筑空调采暖能耗的影响规律,找出了五个气候区建筑南向窗墙比、窗户类型、水平遮阳板长度之间合理的匹配关系,对建筑的节能设计起到了重要的指导作用。     

基于海南气候条件的南向外窗遮阳设施性能分析

海南省太阳辐射强烈,建筑遮阳是营造良好室内环境的重要途径。本文以海口市气象条件为例,分析了水平遮阳设施参数变化对南向外窗遮阳性能的影响。研究发现,在一定范围内通过增加遮阳板的长度以及宽度对其遮阳性能有明显提升,但进一步增加则影响甚微。同时采用双层水平遮阳时,下层遮阳板的安装位置对外窗的遮阳性能影响很大。     

西安地区办公建筑南窗水平遮阳研究

通过窗户的太阳辐射对建筑夏季空调能耗和冬季采暖能耗有着重要的影响,对于南向窗户来说水平遮阳方式比较有效.以西安地区办公建筑南向窗户为研究对象,借助Energyplus等软件,分析了夏季通过南窗太阳能辐射得热问题,综合考虑不同水平遮阳板宽度对建筑采暖和空调负荷的影响,得出了遮阳板最佳设计尺寸.     

水平遮阳板角度在建筑节能与采光分析中的综合应用

建筑物外水平遮阳板的设置与建筑物外窗的朝向、不同时刻的太阳高度角与太阳方位角等因素相关。为了使水平遮阳板在不同时刻、不同朝向能充分发挥遮阳板的建筑节能效果,并能同时满足建筑采光要求,水平外遮阳应采用可调方式,并且能够根据时间与季节的变化进行调节。理论分析了影响水平遮阳效果的因素,并根据理论推理建立2个尺寸统一的水平外遮阳数学模型,分析不同角度的水平遮阳板在不同时间的遮阳效果。基于分析结果,结合水平外遮阳对建筑节能的影响,并综合考虑建筑的采光要求,得出南京地区建筑正南面外窗的水平外遮阳不同时刻的角度调控策略。     

基于外遮阳系数的南向窗口水平遮阳板构型尺寸设计

根据丽水市的地理位置、太阳运行规律,采用外遮阳系数衡量遮阳效果,计算确定了该区域建筑南向窗口水平遮阳板的构型尺寸,为当地建筑遮阳设计提供依据。     

光伏电池板不同朝向的最佳安装倾角

将天津地区标准年气象数据作为基础数据,采用MATLAB软件计算倾斜光伏电池板获得的太阳辐射量。光伏电池板朝南时,安装倾角0°40°、50°70°、80°获得日均太阳辐射量最大月分别出现在5月、4月、2月;安装倾角越大,光伏电池板获得的日均太阳辐射量的变化幅度越小。光伏电池板最理想的朝向为南向,最佳倾角随着方位角(定义为朝南时方位角为零,随着向西偏转,方位角逐渐增大,当朝西时方位角为90°)的增大逐渐减小。方位角0°10°、20°60°、70°、80°90°对应的最佳安装倾角分别为30°、20°、10°、0°。     

"夏氏遮阳"的遮阳效果分析

建国初期,岭南建筑实践的领军人物夏昌世教授在岭南现代建筑创作中建造了许多使人耳目一新的"夏氏遮阳"建筑.本文以建筑技术角度,定量的分析和评价"夏氏遮阳"的遮阳效果.水平遮阳板和垂直遮阳板相结合的"夏氏遮阳"的遮阳效果好,遮阳系数为0.24～0.29,并且能够满足夏季和冬季对太阳辐射量的不同要求.     

Impacts of the shading-type building-integrated photovoltaic claddings on electricity generation and cooling load component through shaded windows

The shading-type building-integrated photovoltaic (BIPV) claddings can act as power generators as well as external shading devices of a building, which reduce the energy consumption of the building. However, there is little information about energy impacts of different tilt angles of the shading-type BIPV claddings. By considering the typical meteorological conditions of Hong Kong, the energy performance of the shading-type BIPV claddings, in terms of the electricity generation and the cooling load reduction, is analyzed in this paper. The optimum tilt angle of PV modules for maximum electricity generation is found to be 20° instead of local latitude. Combining electricity generation and cooling load reduction, it can be concluded that the optimum tilt angles for the first type of the shading-type BIPV claddings vary from 30° to 50°, while the optimum tilt angle for the second type is 0°.     

Compromises between form and function in grid-connected,building-integrated photovoltaics (BIPV) at low-latitude sites

The integration of photovoltaic (PV) modules on building façades and rooftops is an ideal application of solar electricity generators in the urban environment. Maximum annual performance of grid-connected PV is usually obtained with modules tilted at an angle equal to the site latitude, facing the equator. The performance of PV systems not tilted and oriented ideally can drop considerably, depending on site latitude. With grid parity – when the cost of solar electricity becomes competitive with conventional electricity – expected in many countries in the present decade, a more widespread application of PV on buildings is expected, and in this context the main goal of this paper is to demonstrate that good compromises between form and function are possible. In this work we compare the annual energy generation of a curved BIPV system installed as a car port rooftop, with an ideally-oriented and tilted, flat BIPV system installed as a building’s rooftop cover at a low-latitude site (27°S). For the one-year period analysed, the curved-shape BIPV system annual yield was 12% lower than that of the reference BIPV system, and during the summer months (November to February), the curved BIPV installation presented a higher energy yield than the latitude-tilted generator. With these results we show that a good compromise can be reached between form and function in BIPV systems.     

The impact of building-integrated photovoltaics on the energy demand of multi-family dwellings in Brazil

Brazil faces a continuous increase of energy demand and a decrease of available resources to expand the generation system. Residential buildings are responsible for 23% of the national electricity demand. Thus, it is necessary to search for new energy sources to both diversify and complement the energy mix. Building-integrated photovoltaic (BIPV) is building momentum worldwide and can be an interesting alternative for Brazil due its solar radiation characteristics. This work analyses the potential of seven BIPV technologies implemented in a residential prototype simulated in three different cities in Brazil (Natal, Brasília and Florianópolis). Simulations were performed using the software tool EnergyPlus to integrate PV power supply with building energy demand (domestic equipment and HVAC systems). The building model is a typical low-cost residential building for middle-class families, as massively constructed all over the country. Architectural input and heat gain schedules are defined from statistical data (Instituto Brasileiro de Geografia e Estatística—Brazilian Institute for Geography and Statistics (IBGE) and Sistema de Informações de Posses de Eletrodomésticos e Hábitos de Consumo—Consumer Habits and Appliance Ownership Information System (SIMPHA)). BIPV is considered in all opaque surfaces of the envelope. Results present an interesting potential for decentralized PV power supply even for vertical surfaces at low-latitude sites. In each façade, BIPV power supply can be directly linked to local climatic conditions. In general, for 30% of the year photovoltaic systems generate more energy than building demand, i.e., during this period it could be supplying the energy excess to the public electricity grid. Contrary to the common belief that vertical integration of PV is only suitable for high latitude countries, we show that there is a considerable amount of energy to be harvested from vertical façades at the sites investigated.     

Simplified method of sizing and life cycle cost assessment of building integrated photovoltaic system

This paper presents methodology to evaluate size and cost of PV power system components. The simplified mathematical expressions are given for sizing of PV system components. The PV array size is determined based on daily electrical load (kWh/day) and number of sunshine hours on optimally tilted surface specific to the country. Based on life cycle cost (LCC) analysis, capital cost (US$/kW_P) and unit cost of electricity (US$/kWh) were determined for PV systems such as stand-alone PV (SAPV) and building integrated PV (BIPV). The mitigation of CO₂ emission, carbon credit and energy payback time (EPBT) of PV system are presented in this paper. Effect of carbon credit on the economics of PV system showed reduction in unit cost of electricity by 17-19% and 21-25% for SAPV and BIPV systems, respectively. This methodology was illustrated using actual case study on 2.32 kW_P PV system located in New Delhi (India).     

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.     

Modeling of energy performance of a house with three configurations of building-integrated photovoltaic/thermal systems

A theoretical and experimental study of energy performance of three different open loop air heating building-integrated photovoltaic/thermal (BIPV/T) systems that utilize recovered heat for home heating is presented. The configurations are: Configuration 1: base case of unglazed BIPV with airflow under it; Configuration 2: addition of 1.5 m vertical glazed solar air collector in series with Configuration 1; Configuration 3: addition of a glazing over the PV. The model developed has been verified against experimental data from a solar research house for Configuration 1. Obtained relationships for BIPV/T system exiting air temperature as function of solar irradiance and air speed in PV cavity may be used for developing fan airflow control strategies to achieve desired outlet air temperature suitable for different applications. For Configuration 1, preheated air is suitable for HVAC system and domestic hot water (DHW) preheating. Higher outlet air temperatures of the PV cavity suitable for DHW might be achieved by utilizing Configurations 2 or 3. With Configuration 2, significant outlet air temperatures are achieved in winter along with enhanced thermal efficiency making it suitable for coupling with a rockbed heat storage. Finally, Configuration 3 significantly reduces electricity production and may lead to excessively high PV panel temperatures.     

A nodal thermal model for photovoltaic systems: Impact on building temperature fields and elements of validation for tropical and humid climatic conditions

This article deals with both an experimental study and a numerical model of the thermal behaviour of a building whose roof is equipped with photovoltaic panels (PV panels). The aim of this study is to show the impact of the PV panels in terms of level of insulation or solar protection for the building. Contrary to existing models, the one presented here will allow us to determine both the temperature field of the building and the electric production of the PV array. Moreover, an experimental study has been conducted in La Reunion Island, where the climate is tropical and humid, with a strong solar radiation. In such conditions, it is important to minimise the thermal load through the roof of the building. The thermal model is integrated in a building simulation code and is able to predict the thermal impact of PV panels installed on buildings in several configurations and also their production of electricity. Basically, the PV panel is considered as a complex wall within which coupled heat transfer occurs. Conduction, convection and radiation heat transfer equations are solved simultaneously to simulate the global thermal behaviour of the building envelope including the PV panels; this is an approach we call ‘integrated modelling’ of PV panels. The experimental study is used to give elements of validation for the numerical model and a sensitivity analysis has been run to put in evidence the governing parameters. It has been shown that the radiative properties of the PV panel have a great impact on the temperature field of the tested building and the determination of these parameters has to be taken with care.     

光伏建筑一体化设计与运行分析

以深圳地区某光伏建筑一体化示范项目为例,详细介绍其光伏建筑一体化的设计形式,分析光伏发电系统作为建筑构件一部分在兼顾发电同时所起到的建筑功能作用;通过深入研究运行期间该光伏发电系统的各项监测数据,分析采用不同类型光伏组件、安装在不同位置的情况下各光伏发电子系统的太阳辐射与发电量关系,以及单位峰瓦发电量、发电效率等数据指标,对比各光伏发电子系统的运行效果,给出光伏建筑一体化的设计建议,为后续类似项目提供参考借鉴。     

Techno-economic performance analysis of the smart solar photovoltaic blinds considering the photovoltaic panel type and the solar tracking method

In urban areas with dense buildings,it is expected that the building-integrated photovoltaic( BIPV) system,will become widespread. Especially,the solar photovoltaic blinds( SPB),which can block the sunlight coming into the room and produce electricity,is emerging as a new technology trend. To facilitate the installation of the SPB,this study analyzed the techno-economic performance of the smart SPB considering the PV panel type and solar tracking method used. Towards this end,this study conducted experiments using the developed smart SPB,as well as a comparative analysis in terms of the techno-economic aspects based on the experiment results. The analysis results of this study were as follows: at the same cost,( i) the monocrystalline silicon( mono-Si) PV panel generated 350. 5% more electricity than the amorphous silicon( a-Si) PV panel; and( ii) the direct solar tracking system generated 12. 9% more electricity than the indirect solar tracking method.Accordingly,the mono-Si PV panel and the direct solar tracking method were selected for the optimal smart SPB. The installation of the smart SPB with the proposed optimal design on the south-facing window of buildings can be helpful for raising the electricity selfsufficiency rate of buildings by up to 20. 3%.     

武汉国际博览中心屋面太阳能光伏发电应用研究

武汉国际博览中心项目为武汉市最大的公共建筑.以武汉国际博览中心项目为背景,进行了屋面太阳能光伏发电技术难点分析,并介绍太阳能光伏系统关键技术,包括光伏组件铺设场地选择、光伏建筑一体化设计、并网系统设计、BIM技术等相关保障技术,最后对项目节能效果进行分析.武汉国际博览中心屋面太阳能光伏发电系统达到了发电、保温节能、装饰的目的,也对其他相关大型项目起到示范作用.