Integrating PV panels as eaves in an universitary building. Their GHG emission reduction potencial from a life cycle perspective

ARENA, A.P.; HENDERSON, G.; BELLO, C.; PANELLA, L; MARTÍNEZ, M.; SALASSA, A.

Buenos Aires

Congreso; 5th International Solar Cities Congress; 2014

ISCI

In this article the simulated results for a demonstrative photovoltaic system integrated to the envelope of a university building located in the city of Mendoza are presented. The PV panels are used as eaves in the north-faced walls from the main building of the National Technological University, Campus Mendoza, while reducing the building?s energy demand from the public grid. In this way the PV panels play a role as a micro- power generation plant and as a building element which adds value to the architecture. Taking advantage of the interdisciplinary capabilities of the professionals involved in the project, including civil and electromechanical engineers and students, and specialists on sustainable buildings, the team was able to incorporate many features and strategies pursuing sustainable conditions, both from the economic and environmental point of view. The process was performed trading off the cost of the different design alternatives against the future direct energy benefits, focusing only on building-integrated solutions with high visibility, enhancing the impact of the project on the local university community. The design of the PV supporting structure was developed with the aim of optimizing the energy generation through the different seasons of the year while blocking the direct radiation directed towards the classrooms? windows, mainly during the warmer months. This is performed by means of a manually-driven, horizontal-axis tracking system. The supporting structure is designed to revolve round a horizontal axis, and is capable of being blocked in all positions due to the high reduction-rate of the gearbox used to modify the panel angle. The design is useful also for facilitating the cleaning of the PV panel surfaces, by rotating the structures 180ª without need of climbing up to the roof. A vertical position can be adopted for protecting the PV panels in case of adverse weather with risk or hail, which is not a rare phenomenon in the region. Distributed generation allows the production of electricity where the consumption is made, diminishing transmission losses and trading only the difference between the total energy consumed and the energy produced. The developed building-integrated system avoids the need of constructing and installing two different structures: an overhang for controlling of the incident radiation into the north-faced classrooms and a traditional PV system in the roof, allowing for a better use of limited resources. The system?s capacity is small compared with the demand of the building, but it play a role as a demonstrative installation aimed at improving the knowledge about different problems related with PV distributed generation in the region: lack of a suitable electric regulatory system, electricity quality, monitoring, urban morphology, environmental impact, costs, public awareness, building integration, etc. Results present an interesting potential for decentralized, building-integrated PV power supply, which are likely to play a more significant role in the near future. The installation will provide lower annual costs for energy bills, and will improve thermal comfort in classrooms. Initial costs constitute a barrier for the spreading of the technology, but integrated design and double functioning are the key elements within the design team?s reach for lowering them. The simulated results show an interesting diminution of GHG emissions per kWh produced, compared with the conventional sources and from a life cycle perspective.