Daylighting And Energy Consumption Research On Photovoltaic Glass Application To High-rise Office Building In Tianjin

Against the background of building energy conservation and comprehensive utilization of renewable energy, building integrated photovoltaics has got the great opportunity of development, especially the integrated application of photovoltaic modules to the facade of the modern buildings. Compared with the previous common modules, the photovoltaic glass can not only generate electricity, but also brings the complex energy efficiency by the transmission of the light into the room and gradually become the main form of BIPV (Building integrared photovoltaic).There were large amount of High-rise office buildings existed, and especially in the mega cities, with the increasingly scarce land resources, high-rise office building has become an irreversible trend of the future office space form. For now, however, two disadvantages were widely existed in the high-rise office buildings:1) the indoor daylighting environment problems such as the uneven distribution of illumination and glare of the office space;2) the building energy consumption keeps high.The application of the photovoltaic glass can present a solution in theory to improve the situation that existed in the high-rise building and it has advantages on integration with the photovoltaics.This paper was mainly about the application of photovoltaic glass to the window of high-rise office space in Tianjin, to analyse the the relationship between the cell coverage area ratio of the photovoltaic glass and the daylighting quality of the office space, building energy consumption and electricity generation between different buildings aiming to determine the suitable cell coverage area ratio (interval) of the photovoltaic glass in different orientations which both met the daylighting environment demand for office space and achieve lower total energy consumption of office buildings. Studies are mainly from the following aspects:First, basing on the hour-to-hour daylight climate data of the whole year in Tianjin, dynamic and static daylighting simulation comparison and quantitative evaluation toward daylighting environment of the indoor office space using photovoltaic glass in different orientations were done respectively, aiming at finding out the photovoltaic cell coverage area ratio (interval) which will meet the indoor daylighting environment quality requirements and achieve the desired daylighting environment;Second, analysis of the energy consumption in lighting, heating and cooling, total energy consumption, and electricity generation when photovoltaic glass was used in different directions of the office space in Tianjin were made to find the best photovoltaic cells coverage area ratio (interval) corresponding to the lowest total energy consumption of the building;Third, a comprehensive considerations was made between the daylighting performance and the energy performance when using photovoltaic glass in typical office space to determine the best photovoltaic cell coverage area ratio;Finally, a single layer transparent glass and a high permeability Low-e insulating glass were chosen to compare with the performance of the photovoltaic glass by simulating its lighting performance and energy performance, to explore the applicability of the photovoltaic glass in office buildings of Tianjin.The main conclusions drawn in this study are:1. Basing on the daylighting performance of photovoltaic glass in the office space toward different oritentations, the suitable cell coverage area ratio to achieve the lighting quality were:10%-60% to the south, and 10%-40% for the rest; the best cell coverage area ratio to achieve the ideal daylighting environment were 60% to the south, and 40% for the rest. It can obviously improve the DA with the 3-5m depth area when adopting the best cell coverage area ratio and the improvement effect by 247.3% for the east was the most obvious, and followed by the west,southeast,southwest and south; It can obviously improve the UDI with the 0-3m depth area and the improvement effect by 147.7% for the east was the most obvious, and followed by the southwest, south,southeast and East.2. Basing on the energy performance of the photovoltaic glass in the office space toward different oritentations, the suitable cell coverage area ratio to achieve the lowest energy consupmtion were 60-80% to the south and southeast; 10% and 40% to the southwest; 70% to the East and 80% to the West. Adopting the best photovoltaic cells coverage area ratio, the energy consumption saved for the south, southeast, southwest, east and west oritentions respectively were 7.0%、10.0%、5.60%、6.3% 和5.0% when compared to the most unfavorable conditions.3. The cell coverage area ratio of photovoltaic glass has a great influence on the indoor daylighting environment and the total building energy consumption. The optimal cell coverage area ratio (interval)was existed and varied with the different orientations of the building. Considering both the lighting performance and the energy performance of the photovoltaic glass, the best cell of the photovoltaic glass used in the office building of Tianjin were determined,60% for the South, and 40% for the rest. Adopting the optimal cell coverage area ratio is the most meaningful in the south oritention for it has the most obvious effects on both the UDI and energy saving.4. Studies have shown that the application of photovoltaic glass to high-rise office buildings in Tian Jin, can not only improve the indoor daylighing environmental quality, but also reduce the total building energy consumption. Recommended application was suggested in TianJin Area.(1) The daylighting performance of the photovoltaic glass is better than the other two types of glasses. It can significantly improve the daylighting quality of the areas within certain depth of the roon which near the window and effectively reduce the adverse effects of direct light. Of the five oritentions, as compared to the other two types of glass, the improvement for the indoor daylighting effect using the is the most obvious when applied to the south, followed by east, southeast and southwest and the west was relatively small. Compared with the other two types of glass, the photovoltaic glass has the advantage on the visual comfort for it can reduce the glare.(2) In the five oritentions of the office space, the total annual energy consumption values using photovoltaic glass were lower than the other two types of glass. Compared to the single transparent glass, the energy saving effect in the west is the most obvious by the energy-saving rate of 48.4%, followed by south, southwest,east, southeast; Compared to the application of high permeability Low-e insulating glass, the energy saving effect in the west is also the most obvious by the energy-saving rate of 46.0%, followed by south, southeast, southwest, east.The results of the study can provide theoretical support for the application and popularization of photovoltaic glass in high-rise office building in TianJin and promote the development of building integrated Photovoltaics.