Modeling the life cycle energy and environmental performance of amorphous silicon BIPV roofing in the US

Building integrated photovoltaics (BIPV) perform traditional architectural functions of walls and roofs while also generating electricity. The displacement of utility generated electricity and conventional building materials can conserve fossil fuels and have environmental benefits. A life cycle inventory model is presented that characterizes the energy and environmental performance of BIPV systems relative to the conventional grid and displaced building materials. The model is applied to an amorphous silicon PV roofing shingle in different regions across the US. The electricity production efficiency (electricity output/total primary energy input excluding insolation) for a reference BIPV system (2kW_p PV shingle system with a 6% conversion efficiency and 20 year life) ranged from 3.6 in Portland OR to 5.9 in Phoenix, AZ indicating a significant return on energy investment. The reference system had the greatest air pollution prevention benefits in cities with conventional electricity generation mixes dominated by coal and natural gas, not necessarily in cities where the insolation and displaced conventional electricity were greatest.     

Modeling, design and thermal performance of a BIPV/T system thermally coupled with a ventilated concrete slab in a low energy solar house: Part 1, BIPV/T system and house energy concept

This paper is the first of two papers that describe the modeling, design, and performance assessment based on monitored data of a building-integrated photovoltaic-thermal (BIPV/T) system thermally coupled with a ventilated concrete slab (VCS) in a prefabricated, two-storey detached, low energy solar house. This house, with a design goal of near net-zero annual energy consumption, was constructed in 2007 in Eastman, Québec, Canada - a cold climate area. Several novel solar technologies are integrated into the house and with passive solar design to reach this goal. An air-based open-loop BIPV/T system produces electricity and collects heat simultaneously. Building-integrated thermal mass is utilized both in passive and active forms. Distributed thermal mass in the direct gain area and relatively large south facing triple-glazed windows (about 9% of floor area) are employed to collect and store passive solar gains. An active thermal energy storage system (TES) stores part of the collected thermal energy from the BIPV/T system, thus reducing the energy consumption of the house ground source heat pump heating system. This paper focuses on the BIPV/T system and the integrated energy concept of the house. Monitored data indicate that the BIPV/T system has a typical efficiency of about 20% for thermal energy collection, and the annual space heating energy consumption of the house is about 5% of the national average. A thermal model of the BIPV/T system suitable for preliminary design and control of the airflow is developed and verified with monitored data.     

Low light conditions modelling for building integrated photovoltaic (BIPV) systems

The low irradiance efficiency of photovoltaic modules is important to the optimization of BIPV systems. When photovoltaic modules are integrated into a building, architectural design considerations compete with maximizing photovoltaic energy production. As a result, BIPV arrays are often not facing south and are frequently mounted vertically. Under these conditions, a greater portion of the total sunlight striking the array is diffuse or at high angles of incidence. In northern latitudes a significant amount of the total yearly energy is produced at low light levels.A grid-connected array of BIPV modules integrated into the BCIT Technology Centre building in Burnaby, B.C. was used for assessing the accuracy of an energy performance model developed for BIPV systems. The BIPV system uses AC modules and a computerized data acquisition system for monitoring the performance of modules and inverters. The performance model was developed from analysis of the open circuit voltage, maximum power point voltage and maximum power point current of the individual modules comprising the BIPV array.The algorithm for calculating power output of the photovoltaic array is derived from the ideal diode equation using the single diode model of a photovoltaic cell. An empirically derived parameter modifies the equation. Once the parameters for different module technologies are established, it is possible to compare their annual performance in a BIPV system.     

Different diode models comparison using Lambert W function for extracting maximum power from BIPV modules

Perfect modeling of the building‐integrated photovoltaic (BIPV) module circuit equivalent is required for examining the operation of a BIPV system. Before designing the power electronic converters of an overall BIPV system, a perfect diode modeling is required that usually resembles the I‐V and P‐V characteristics of the BIPV modules. In this research article, different types of diode modeling of BIPV systems along with their comparative analysis based on the Lambert W function in MATLAB/Simulink environment is presented. The main aim of this research article is to analyze Mprime transparent M 115‐130P‐FI BIPV modules (115 Wp and 130 Wp) and compare the existing diode models in terms of accuracy and extraction of unknown parameters for the same. Simulation results for Lambert W function based comparison of the five‐parameter model (FPM), seven‐parameter model (SPM) and nine‐parameter model (NPM) power of 115 Wp and 130 Wp BIPV modules along with their percentage errors are well presented. Lambert W function based comparison of FPM, SPM, and NPM is further made at different values of irradiations and temperatures respectively.     

BIPV/T技术在新徽派民居中的应用探索

针对新徽派民居中存在的建筑能耗大、热舒适性差及室内空气品质低等问题,探索在保持建筑典型特点的前提下,将太阳能光伏光热建筑一体化(BIPV/T)新技术和新方法在新徽派民居中综合运用.文章主要基于作者团队最新的研究,探讨了兼顾"黛瓦"的光伏瓦技术、兼顾"粉壁"的集热?除甲醛多效墙体技术、兼顾"马头墙"的通风?除菌杀毒多效太...     

Available remodeling simulation for a BIPV as a shading device

A building integrated photovoltaic system as a shading device is used as an application and remodeling model. This study applies the simulation program SOLCEL and the computational fluid dynamics method to cases with solar irradiance components analysis and a ventilated double façade remodeling of the BIPV. For the validation of the theoretical work, experimental results of the Samsung Institute of Engineering and Construction Company building are used with a wind velocity of the weather data of Suwon area, Korea, where the real building is located. A photovoltaic system can be used only to generate electricity, but if a photovoltaic module can be used as an element of a double envelope, it could be more useful at the point of view of renewable energy usage and night insulation. Increase of PV module surface temperature is negative for power generation by installing PV module as an element of double envelope. A reasonable combination between renewable energy usage and power generation should be well analyzed for better usage of natural energy to design a BIPV.     

BIPV系统经济性分析

太阳能作为21世纪最具潜力的洁净能源之一,其相关产业在近几年里发展十分迅速。本文论证了在我国发展太阳能产业的可行性,描述了BIPV系统的结构和优越性,并且结合南京市光伏—建筑一体化系统的实例,通过对其发电效益以及动态平直供电成本的计算对该系统的经济性和环境效益进行了分析。计算结果表明,该实例虽然可以带来很好的环境效益,但是目前发电成本偏高。BIPV系统的普及有赖于太阳电池组件产品价格的降低和相关政策的支持。     

Estimating thermal stress in BIPV modules

The thermal stress on building‐integrated photovoltaic modules (BIPV) in Espoo, Finland, was studied with field‐testing of amorphous silicon modules. Based on these results, the thermal stress at two other European locations (Paris and Lisbon) was estimated. The estimation procedure entailed thermal modelling of heat transfer in the façade with meteorological data as input. The results indicate that the thermal stress on BIPV modules in Lisbon is, in this case, approximately 50% higher that in Espoo and between 80 and 200% higher than in Paris, depending on the activation energy of the degradation process. The difference in stress between a BIPV module and a free‐standing module in Espoo was 50–200%. Copyright © 2006 John Wiley & Sons, Ltd.     

贵港供电局光伏建筑一体化项目优化设计研究

对光伏建筑一体化发展应用及需求进行分析,结合贵港供电局办公大楼现有条件进行深入评估,选取最优光伏发电设计方案,充分利用太阳能光电转换技术,解决建筑物的照明、办公等用能需求,为开展节能减排做出带头示范作用,引导全社会共同创造一个科学用电、节能减排、绿色环保的社会环境。     

BIPV: a real-time building performance study for a roof-integrated facility

Building integrated photovoltaic system (BIPV) is a photovoltaic (PV) integration that generates energy and serves as a building envelope. A building element (e.g. roof and wall) is based on its functional performance, which could include structure, durability, maintenance, weathering, thermal insulation, acoustics, and so on. The present paper discusses the suitability of PV as a building element in terms of thermal performance based on a case study of a 5.25?kW_p roof-integrated BIPV system in tropical regions. Performance of PV has been compared with conventional construction materials and various scenarios have been simulated to understand the impact on occupant comfort levels. In the current case study, PV as a roofing material has been shown to cause significant thermal discomfort to the occupants. The study has been based on real-time data monitoring supported by computer-based building simulation model.     

Performance of thin-film BIPV as double sloped pitched roof in buildings of Malaysia

Solar energy in built environments became more popular in the recent years emerging as building integrated photovoltaics (90° façade and 0° roof BIPV). However, in most cases, residential buildings have varying roof pitches instead of 0° roof. In this context, it is significant to assess the energy output and performance of double-sloped pitched roof thin-film BIPV at different angles and orientation. Results show that the performance of the BIPV inclined at 15° and east orientation is better among the other orientation and angles.     

Practical application of building integrated photovoltaic (BIPV) system using transparent amorphous silicon thin-film PV module

An analysis has been carried out on the first practical application in Korea of the design and installation of building integrated photovoltaic (BIPV) modules on the windows covering the front side of a building by using transparent thin-film amorphous silicon solar cells. This analysis was performed through long-term monitoring of performance for 2 years. Electrical energy generation per unit power output was estimated through the 2 year monitoring of an actual BIPV system, which were 48.4 kWh/kWp/month and 580.5 kWh/kWp/year, respectively, while the measured energy generation data in this study were almost half of that reported from the existing data which were derived by general amorphous thin-film solar cell application. The reason is that the azimuth of the tested BIPV system in this study was inclined to 50° in the southwest and moreover, the self-shade caused by the projected building mass resulted in the further reduction of energy generation efficiency. From simulating influencing factors such as azimuth and shading, the measured energy generation efficiency in the tested condition can be improved up to 47% by changing the building location in terms of azimuth and shading, thus allowing better solar radiation for the PV module. Thus, from the real application of the BIPV system, the installation of a PV module associated with azimuth and shading can be said to be the essentially influencing factors on PV performance, and both factors can be useful design parameters in order to optimize a PV system for an architectural BIPV application.     

Modeling and coordinate control of photovoltaic DC building module based BIPV system

This paper presents the modeling method and coordinate control strategy for photovoltaic dc building module (PV-DCBM) based building integrated photovoltaic (BIPV) system. The PV-DCBM based BIPV system consists of plenty of PV-DCBMs and a centralized inverter which are coupled to the common dc bus in parallel. Each PV-DCBM is integrated with a PV building material to extract maximum power from it and then a centralized inverter is used to transfer the power to the grid. The PV-DCBM based BIPV system has some significant advantages for building integrated applications, such as individual MPPT, inherent data monitor, low cost and excellent expandability. A coordinate control strategy based on energy balance of the PV-DCBM based BIPV system is proposed to realize the individual control for each PV-DCBM and the centralized inverter. The accurate small-signal model of the PV-DCBM based BIPV system is built based on the proposed operation principle and a detailed design approach of the coordinate controller is proposed. Experimental results on the laboratory prototype verify the validity of the proposed modeling and coordinate control method.     

Simulation for an optimal application of BIPV through parameter variation

The degree of efficiency of Building Integrated Photovoltaic (BIPV) as a shading device and the variation of the electrical power generation over 1 year in a real building has already been experimentally investigated in my earlier research. In this paper, the influence of the angle of the solar cell panel, albedo of earth, building azimuth, and of solar cell panels under shading on the power generation are theoretically studied to further optimize BIPV implementation. For the validation of the theoretical work, experimental results of the Samsung Institute of Engineering and Construction Company building are used with a wind velocity of the weather data (TRY, test reference year) of Suwon area, Korea. The efficiency of the BIPV system as a shading device was compared at different months. In this work, the simulation program SOLCEL, for the calculation of a shading/sunlit area on solar cell module and facade, surface temperature of solar cell module, effective solar irradiance on solar cell module and the power generation of a BIPV as a shading device, was developed and validated. The SOLCEL can be applied to develop a multi functional Building Integrated Photovoltaic which could improve power generation, thermal comfort, natural lighting, cooling and heating, etc.     

光伏建筑一体化在城市应用中光反射问题的探讨

文章介绍了太阳能光伏发电技术的城市建筑一体化应用形式和目前市场上晶体硅太阳能电池板的减反射特性,比较了不同物质和材质的反射率,分析太阳能光伏建筑一体化应用对城市的光污染影响。     

A framework for evaluating WTP for BIPV in residential housing design in developing countries: A case study of North Cyprus

This paper explores people׳s preferences for a Built in Photovoltaic (BIPV) renewable energy system to be integrated into housing construction. A novel methodology was developed, to study the case of Northern Cyprus, for better understanding of possibilities that abound in BIPV integration. The methodology incorporates Building Information Modeling (BIM) as a real-time design and economic assessment tool for BIPV choices. This serves to benefit both the construction companies and potential house owners in their decision-making. In addition, it uses a Contingent Valuation (CV) method to assess the Willingness to Pay (WTP) and the Willingness to Accept (WTA) compensation. The results indicate that the capital cost of PV is not instrumental in choice, and a lower feed-in tariff could be acceptable.     

Research of BIPV optimal tilted angle,use of latitude concept for south orientated plans

The present study analyzes the correlation between the optimal angle for a fixed Building Integrated Photovoltaic (BIPV) system and the latitude of the system's site as measured in degrees according to estimates made with PVSYST 3.41 software. Calculations were made for a BIPV south orientated tilted roof at 20 different locations in 14 countries, ranging from 0° to 85° latitude in the Northern Hemisphere. In order to prove the reliability of using the latitude angle as the angle for the tilted panel, the correlation was made between the performance obtained with the system using the optimal angle and the system with the site's location angle. Results indicate that an average of 98.6% a system's performance with the optimal angle can be obtained using the latitude angle for the tilted panel.     

Performance monitoring results of the first grid-connected BIPV system in Colombia

This paper summarizes the operational performance results of the first grid-connected building integrated photovoltaic (BIPV) system installed in Colombia (in Bogotá, at 4°35′ latitude and 2.580 m altitude) after two years of monitoring. The performance monitoring was carried out with a sophisticated monitoring system, designed and implemented by us using the virtual instrumentation concept. The following parameters were measured: DC and AC power, inverter and system conversion efficiency, energy generated by the PV array, AC energy produced by the BIPV system, parameters to analyze power quality (%THD, harmonic components, frequency, voltage, flickers, power factor, active power, apparent power and reactive power), solar radiation in the inclination plane of the panels and environment temperature.The data obtained allowed to evaluate the general performance and the quality of the electric power generated by the photovoltaic plant. The results indicated that the power generated by the grid-connected BIPV plant fulfills the specifications demanded for such systems by National and International standards.     

The effect of using two PCMs on the thermal regulation performance of BIPV systems

Building Integrated Photovoltaics (BIPVs) is one of the most promising applications for Photovoltaics (PVs). However, when the temperature in the BIPV increases, the conversion efficiency deteriorates. A PV/PCM system using Phase Change Materials (PCM) for BIPV thermal control has been experimentally and numerically studied previously. One of the main barriers for this application is how to improve the low thermal conductivity of the PCM in order to achieve a quick thermal dissipation response with longer thermal regulation in PVs. Although the metal fins inserted inside the PCM can improve the heat transfer, the thermal regulation period declines as the volume of the PCM is substituted by the metal mass of the PV/PCM system. A modified PV/PCM system integrated with two PCMs with different phase transient temperatures for improving the heat regulation needs to be investigated. The use of combinations of PCMs, each with a set of different phase transient temperatures, is expected to enhance the thermal regulation effect of the PV/PCM system and lengthen the thermal regulation time in PVs. In this study a developed PV/PCM numerical simulation model for single PCM application has been modified to predict the thermal performance of the multi-PCMs in a triangular cell in the PV/PCM system. A series of numerical simulations tests have been carried out in static state and realistic conditions in UK. The thermal regulation of the PV/PCM system with a different range of phase transient temperature PCMs has been discussed.