System performance of a three-phase PV-grid-connected system installed in Thailand: Data monitored analysis

PV-grid-connected systems are worldwide installed because it allows consumer to reduce energy consumption from the electricity grid and to feed the surplus energy back into the grid. The system needs no battery so therefore the system price is very cheap comparing to other PV systems. PV-grid-connected systems are used in buildings that already hooked up to the electrical grid.Finding efficiency of the PV-grid-connected system can be done by using a standard instrument which needs to disconnect the PV arrays from the grid before measurement. The measurement is also difficult and we lose energy during the measurement.This paper will present the system performance of a PV-grid-connected system installed in Thailand by using a monitoring system. The monitored data are installed by acquisition software into a computer. Analysis of monitored data will be done to find out the system performance without disconnecting the PV arrays from the system. The monitored data include solar radiation, PV voltage, PV current, and PV power which has been recorded from a 5 kWp system installed of amorphous silicon PV at Rajamangala University of Technology Suvarnabhumi, Nonthaburi, Thailand. The system performance of the system by using the data monitored is compared to the standard instrument measurement. The paper will give all details about system components, monitoring system, and monitored data. The result of data analysis will be fully given.     

Performance results and analysis of 3 kW grid-connected PV systems

Four 3 kW grid-connected photovoltaic (PV) generation systems have been installed and monitored at the Field Demonstration Test Center in Korea since October 2002. To observe the overall effect of meteorological conditions on their operation characteristics by field test, the monitoring system has been constructed for measuring and analyzing the performance of PV systems and components in November 2002. In this paper, the performance of PV systems is evaluated and analyzed not only for component perspective but also for global perspective by reviewing one year of monitoring results and loss factors of PV systems. On the basis of these monitoring results, the performance of PV systems is compared to the measured performance of PV systems with the estimated performance by simulation. These results will indicate that it is highly imperative to develop evaluation, analysis and application technology for PV systems.     

Comparison of theoretical and real energy yield of direct DC-power usage of a Photovoltaic Façade system

Multifunctional façade components have nowadays become a significant research topic as a step towards developing energy-efficient buildings. This paper presents the performance evaluation of an experimental setup of a real fully decentralized façade-integrated photovoltaic (PV) system installed in a prototype façade, for direct DC power use. The goal of this evaluation was to test the system's ability to fulfill a pre-designed daily electrical load of 925Wh corresponding to a three-people office space under 100% decentralization. This was achieved by studying the operation under different weather conditions and the impact of the system design and components on its overall output. The evaluation of both the actual and theoretical system outputs indicates poor actual system performance in terms of low energy yield and unacceptable load fulfillment factor, which did not exceed 0.95. At the same time it revealed underutilized system potential which could be exploited theoretically with a proper system configuration. The results in this paper conclude that decentralized façade integrated PV systems can completely satisfy their designated applications if properly-designed and implemented, and provides a methodology which could be used in designing similar systems. Satisfactory fulfillment is shown to be achieved by having 30% additional PV and 9 times bigger storage capacities in this system.     

An approach to the selection of the inverter for architecturally integrated photovoltaic grid-connected systems

An optimal compromise between energy efficiency and aesthetics for PV in the built environment sometimes requires to divide the PV field into sections with different orientation and tile each, which are connected to a single inverter. From the experience and data collected through a year of monitoring the 2-Kwp photovoltaic grid-connected system installed on the flat roof of the High Technical School of the University of Jaen, some charts are presented to help architects, engineers and installers to select the most suitable inverter for two specific architectural solutions addressed to integrating PV in buildings. However, charts for other sites, climates and architectural designs can be easily obtained.     

On-site performance of electrochromic glazings coupled to an anidolic daylighting system

This work takes benefit from two advanced building technologies through the integration of an anidolic daylighting system and an electro-chromic glazing in a building facade for achieving an optimal control of the daylight flux entering in an office room. Computer simulations of different systems configurations, based on ray-tracing techniques, were used to identify the optimal anidolic system design. Once installed in an experimental building the visual and thermal performance of the anidolic system coupled to an electrochromic glazing was assessed by way of on-site monitoring. These performances were compared to those offered by a conventional double glazing unit installed in an identical neighbouring room. An evaluation of users comfort was achieved by way of a survey involving 30 different subjects. Their visual performance during specific tasks performed on a VDT screen and/or on a sheet of paper was used to compare the lighting conditions. The main results of this detailed experimental study, showing the capability of such a combined daylighting system to control the daylight flux entering a working space, are presented in this paper.     

Experience on integration of solar thermal technologies with green buildings

The green buildings of Shanghai Research Institute of Building Science include an office building for the demonstration of public building and two residential buildings, which are for the demonstration of flat and villa, respectively. Here, a solar-powered integrated energy system including heating, air-conditioning, natural ventilation and hot water supply was designed and constructed for the office building. However, only solar hot-water systems were installed for the flat and villa. All the three solar thermal systems have continuously run for 2 years. Two different integrated approaches have been put into practice in the two green residential buildings. It is shown that, for new buildings, solar collectors can be mounted on balconies and awnings besides roofs, on condition that solar systems become part of the general building design. The solar-powered integrated energy system has the advantage of high utilization ratio with different functions according to different seasons. It is testified to be capable of taking on about 70% of the yearly building load regarding the involved space under the weather condition of Shanghai.     

Building-integrated PV installations in the Netherlands: Examples and operational experiences

Building-integrated PV started receiving attention in the Netherlands around 1990. Attention has ever since been focusing on the integration of PV into new dwellings. Efforts have resulted in cost reductions, performance improvements, the development of new integration products and the creation of a network with utilities, property developers, architects, building companies and local authorities. PV system costs have been reduced by one third, to 5 Euro in 2000. System performance has gone up slightly during the reporting period, further reducing the costs per unit energy produced. Inverter costs have gone down from 1.5 Euro/Wp in 1991 to 0.5 Euro/Wp in 2000. Concerning integration into buildings and the building process, the Netherlands PV programme has been concentrating on developing products for low-cost integration into sloped roofs of new buildings. Watertight profile systems have been developed, tested, and applied in projects on a growing scale. The costs for building integration have come down due to improvements in integration systems, the electric system and in installation procedures. Projects have also been carried out on an increasing scale to learn about the integration of PV into the building process. In total, a capacity of more than 8 MW was installed by the end of the year 1999, with projects ranging from individual dwellings and offices to solar cities such as the Nieuw Sloten project in Amsterdam (250 kWp) and Nieuwland in Amersfoort (1 MW). Now, at the turn of the century, plans are being derived to give PV the ‘boost’ to become commercially viable within the next 7 to 10 years. For this, an ambitious goal is being formulated by government together with the PV industry, utilities, the building sector and others involved in PV in the Netherlands. Already in the mid-1990s, the long-term energy programme of the ministry of Economic Affairs set the target at an installed PV capacity of 250 MWp by the year 2010. In order to achieve a commercially viable market within the next 7 to 10 years, however, a goal of 500 MWp installed PV capacity would be required. Recent research shows that such a target is ambitious, but achievable if supported by dedicated government programmes, investments by industry and contributions of the building and utility sector.     

Hammarby Sjöstad–an interdisciplinary case study of the integration of photovoltaics in a new ecologically sustainable residential area in Stockholm

The integration of photovoltaic (PV) systems in apartment buildings in a new residential area, Hammarby Sjöstad in Stockholm, has been studied using an interdisciplinary approach including e.g. interviews with actors and modelling of PV systems in PVSYST. Four of the ten construction companies represented in the area will install PV systems. The yearly electricity production from these systems has been estimated to be 63 MWh or equal to an electricity demand of 38 (out of 2300) households in the area. Interviews reveal that obstacles for the integration of PV in buildings are e.g. perceived expense and a lack of knowledge. The choice of PV technology is based more on economy, aesthetic appearance, and a wish to demonstrate environmental concern, than on optimal system performance. By integrating renewable energy technologies in the buildings, the construction companies will lay a ground for an ecologically sustainable living, but how these opportunities are utilised by future residents, managers, and caretakers of the buildings will be of decisive importance for the final outcome.     

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.     

Photovoltaic modules in buildings: Performance and safety

Many PV systems exhibit a poorer performance as is to be expected using installed peak power. Performance ratios of ‘reasonable’ systems have experimentally been determined in the range of 60%–85% of STC (=standard test conditions) performance. A significant part of the losses is due to the performance deviation of PV modules from their rating at STC due to the outdoor conditions (realistic reporting conditions, RRC). This is due to low light level dependence, temperature coefficients, nominal operating cell temperatures and reflectivity at the module surface. Due to the special operating conditions, this is of special importance if PV modules are integrated into buildings. To overcome the problems in module performance evaluation and to assist system sizing, a realistic PV efficiency map and performance data for commercial PV modules are presented. In a similar way as the European radiation atlas for solar irradiation, this RRC market survey of PV modules gives detailed information on module performance at many sites for various installation conditions.As the International Electrotechnical Commission is currently preparing a new international standard, dealing with the safety of PV modules in a variety of application classes, performance data on PV modules is supplemented by information on possible module safety tests and module integration into buildings.     

Optimum thermal design of office buildings

Proper design and selection of building components at the early stages of the design process can greatly help in achieving thermal comfort with minimum reliance upon HVAC systems and, therefore, minimum energy requirements. Given today's complexities in building design as well as advances in computer technology, optimization techniques can be used as an aid to building designers in their decision making process. Office buildings are characterized by being ‘internal-load’ dominated with internal heat generation determining the need for energy to air-condition such buildings. This paper presents the results of applying an optimization model to the design of energy conserving office buildings in different climatic regions to test the impact of mainly envelope related parameters on the thermal performance of offices. Optimum sets of building design variables for three different sizes office building in four U.S. and two Saudi Arabian cities are presented with the objective of minimizing annual energy consumption for those buildings. © 1997 John Wiley & Sons, Ltd.     

太阳能光伏光热建筑一体化系统的研究

太阳能光伏光热一体化不仅能够有效降低光伏组件的温度,提高光伏发电效率,而且能够产生热能,从而大大提高了太阳能的转换效率。对光伏光热建筑一体化(BIPV/T)系统的两种主要模式:水冷却型和空气冷却型系统的工作原理和系统模型进行了理论介绍,详细说明了两种系统中热产品在家庭中的应用。并对目前研究情况下两个系统中存在的问题提出了改进方案。与常规建筑相比,光伏光热建筑减少了墙体得热,改善了室内空调负荷状况,提高了建筑节能效果。     

Status report of Task VII of the IEA program: PV in buildings

On January 1, 1997, a new Task started within IEA's PV Power Systems Program: Task VII. Objective of Task VII is to enhance the architectural quality, the technical quality and the economic viability of PV systems in the built environment and to assess and remove non-technical barriers for their introduction as an energy-significant option.The value of building integration for the introduction of grid connected PV is recognized around the world. Rooftop programs, aiming at large-scale application in the next century are carried out in many countries. In order to reach this widespread application, however, cost reductions still are essential. BIPV R&D should therefor focus on achieving these cost reductions, by optimizing integration concepts, by developing new building products and by the development of standardized products.Building integrated PV does not only offer perspectives for the next century. PV systems are installed today by building owners who appreciate the added value of solar roofs and facades, and who are willing to pay a premium for PV. This market potential must be captured and assisted. From the R&D side, this can be done by focusing on architectural issues and on non-technical barriers that impede short-term market penetration. The work in Task VII concentrates on all these aspects. The Task VII R&D strategy is to enhance systems technologies, to work on the architecture of building integrated PV and to assess and remove non-technical barriers that impede the widespread application of PV in the built environment.     

Promotion of grid-connected photovoltaic systems in Spain: Performance analysis of the period 1998–2008

This paper contributes a critical view of the development of grid-connected photovoltaic systems (GCPVS) in Spain during the period 1998–2008 by looking into the different actions that were intended to promote this technology. The Spanish photovoltaic (PV) sector has undergone bullish development in the recent years, but its underlying factors still lack systematic identification and analysis. Accordingly, this paper collects and presents detailed data for describing this evolution. It also makes a special case of the particular promotion of PV systems on roof and goes further to analyze how these actions have affected GCPVS evolution as well as the magnitude of their impact on its performance. The exponential growth of installed cumulative PV power at the end of this period, which largely exceeded the target set for 2008, is canvassed by building an analogy with feedback control systems. In this approach, market response or the PV power attained is considered as the system output, while the different regulation changes are regarded as control actions aimed at enabling GCPVS to hit the energy target. Such an analysis allows determining the most significant delays and control actions that explain the system's performance. Hence, this study suggests an alternative framework to support the formulation and assessment of energy policy as it puts the emphasis not only on the evolution of the system per se but rather on the performance of the system against the energy target. In this regard, it might contribute to enhance the promotion mechanisms of green technologies.     

Experimental analysis of a condenser heat recovery in an air conditioning plant

A total heat recovery system performances are analysed by monitoring building–plant system long term behaviour. Some of the installed chillers offer in fact the possibility of a total recovery of the heat rejected by condenser. The results are very satisfactory both in energy and economic–financial terms. The experimental test takes advantage of the supervisor just existing in the building. Therefore it is an example of how these control systems can be used not only for safety and management needs, but also for a detailed performance analysis able to permit an easy simulation of the effects of different design and control options.     

Design of a solar collector for year-round climatization

Solar heating systems in buildings have increasingly been studied in the past two decades. In several applications the primary energy demand is now for both heating and cooling, and modern solar collectors should be designed to provide climatization during the whole year. Solar systems are seldom applied in Europe, and large buildings, such as office buildings and schools, continue to be built with mechanical ventilation systems.The study presented in this paper is part of a European XVII Thermie project entitled “Pilot project for photovoltaic, energetic and biohousing retrieval in a school”, whose aim was to install a photovoltaic plant and solar air collectors coupled with a sun breaker structure at a scientific high school in Umbertide, in central Italy.This paper describes the research and development activities concerning a solar air collector suited for winter heating and summer ventilation, which was installed at the high school. The collector physical and numerical modelling of heat transfer and fluid flow in winter operation is presented. The system performance has been estimated as a function of different parameters in order to provide a tool for the design process. Furthermore, the climate in the area has been simulated through the available experimental data, and the system behavior under these conditions is presented.The collectors were installed at the scientific high school in Umbertide in spring 2001. Summer ventilation cooling is under testing and an experimental test period is foreseen next winter to validate the design of the collectors and their performance.     

Photovoltaic electricity scenario analysis in urban contests: An Italian case study

This paper shows a methodology for the assessment of the photovoltaic potential in urban areas using Google Earth™ tool that provides either satellite images of the roofs of buildings or their number of floors by means of the Street View function. The applicability of the methodology has been tested on a selected urban area of the city of Palermo in the South of Italy. After classifying roofs according to the shape, orientation and pitch of buildings with different morphologies, the share of energy generated by the installable PV systems was evaluated with regard to the number of floors. Moreover the coverage of the electricity demand was investigated on the basis of the consumption of electricity of the households. The results of the energy assessment have been screened considering the economic feasibility of grid-connected photovoltaic systems. The proposed methodology permits to select a threshold number of floors of the buildings in correspondence of which the PV system that may be installed, and the consequent production of electricity, may not recover the costs for installation and maintenance of the system. This aspect has also been analyzed by considering the main factors that influence the computation, such as the mismatch between generated and consumed electricity and the shading effects due to the surrounding obstacles. The methodology could also be used to assess the effectiveness of the national incentives to support the diffusion of the PV systems in the short term.     

Performance comparison of a double-axis sun tracking versus fixed PV system

In the present study, performance results of two double axis sun tracking photovoltaic (PV) systems are analyzed after one year of operation. Two identical 7.9 kWp PV systems with the same modules and inverters were installed at Mugla University campus in October 2009. Measured data of the PV systems are compared with the simulated data. The performance measurements of the PV systems were carried out first when the PV systems were in a fixed position and then the PV systems were controlled while tracking the sun in two axis (on azimuth and solar altitude angles) and the necessary measurements were performed. Annual PV electricity yield is calculated as 11.53 MW h with 1459 kW h/kWp energy rating for 28 fixed tilt angle for each system. It is calculated that 30.79% more PV electricity is obtained in the double axis sun-tracking system when compared to the latitude tilt fixed system. The annual PV electricity fed to grid is 15.07 MW h with 1908 kW h/kWp for the double axis sun-tracking PV system between April-2010 and March-2011. The difference between the simulated and measured energy values are less than 5%. The results also allow the comparison of different solutions and the calculation of the electricity output.     

Analysis of variables that influence electric energy consumption in commercial buildings in Brazil

Air conditioning systems in commercial buildings in Brazil are responsible for about 70% share of their energy consumption. According to BEN 2009 (The Brazilian Energy Balance), energy consumption in the residential, commercial and public sectors, where most buildings are found, represents 9.3% of the final energy consumption in Brazil. This paper aims to examine design factors that could contribute to greater reductions of electric energy consumption in commercial buildings, with emphasis on air conditioning. Simulations were carried out using shades and different types of glass, walls, flooring and roofing. The VisualDOE 2.61 was used as a simulation tool for calculating energy consumption of the analyzed building. This paper shows that the energy performance of the building is considerably influenced by the façade protection and shows, through tables, the impact that decisions related to the top-level and façades have on the energy consumption of the building. The authors concluded that the results confirm the importance of taking energy use into account in the very first design stages of the project, since appropriate choices of types of glass, external shading and envelope materials have a significant impact on energy consumption.     

Development of autonomous monitoring and performance evaluation system of grid-tied photovoltaic station

This work aims to improve the existing monitoring systems MS for two grid-connected PV stations GCPVS of URERMS ADRAR, to eliminate its limitations. This improvement consists of developing an MS which is used for two PV stations with different configurations. This MS contains new LabVIEW-based monitoring software for visualizing real-time measured data and evaluating GCPVS performance. In addition, it illustrates the 2D and 3D real-time relationships of PV system parameters, which allow us to understand the dynamic behavior of PV system components. This developed monitoring software synchronizes also the various data acquisition units DAU of GCPVS, allowing simultaneous data access.To perform a reliable performance analysis and a comparative study of different GCPVS based on accurate measurements, the sensor's calibration is performed with its DAU. The MS autonomy is ensured by integrating developed PV-UPS. A graphical user interface is provided for the evaluation of PV-UPS performance.