Building Integrated Photovoltaics: a Concise Description of the Current State of the Art and Possible Research Pathways
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energies Review Building Integrated Photovoltaics: A Concise Description of the Current State of the Art and Possible Research Pathways Bjørn Petter Jelle 1,2 Received: 6 July 2015; Accepted: 24 December 2015; Published: 31 December 2015 Academic Editor: Enrico Sciubba 1 SINTEF Building and Infrastructure, Department of Materials and Structures, Trondheim NO-7465, Norway; [email protected] or [email protected]; Tel.: +47-73-593377; Fax: +47-73-593380 2 Norwegian University of Science and Technology (NTNU), Department of Civil and Transport Engineering, Trondheim NO-7491, Norway Abstract: Building integrated photovoltaics (BIPV) offer an aesthetical, economical and technical solution to integrate solar cells harvesting solar radiation to produce electricity within the climate envelopes of buildings. Photovoltaic (PV) cells may be mounted above or onto the existing or traditional roofing or wall systems. However, BIPV systems replace the outer building envelope skin, i.e., the climate screen, hence serving simultanously as both a climate screen and a power source generating electricity. Thus, BIPV may provide savings in materials and labor, in addition to reducing the electricity costs. Hence, for the BIPV products, in addition to specific requirements put on the solar cell technology, it is of major importance to have satisfactory or strict requirements of rain tightness and durability, where building physical issues like e.g., heat and moisture transport in the building envelope also have to be considered and accounted for. This work, from both a technological and scientific point of view, summarizes briefly the current state-of-the-art of BIPV, including both BIPV foil, tiles, modules and solar cell glazing products, and addresses possible research pathways for BIPV in the years to come. Keywords: building integrated photovoltaics (BIPV); solar cell; state-of-the-art; review; research pathway 1. Introduction As the world’s demand and focus on renewable and non-polluting energy, together with energy efficiency, are ever increasing, zero energy and zero emission buildings are rapidly drawing attention. In order to become a zero energy or zero emission building, such a building needs to harvest energy from its surroundings, where energy from the sun is one of the obvious choices. Building integrated photovoltaic (BIPV) systems, where solar cells are integrated within the climate envelopes of buildings and utilizing solar radiation to produce electricity, may represent a powerful and versatile tool for reaching these goals with respect to both aesthetical, economical and technical solutions. The BIPV systems replace parts of the conventional building materials and components in the climate envelope of buildings, such as the roofs and facades. According to Peng et al., BIPV systems are considered as a functional part of the building structure, or they are architecturally integrated into the building’s design [1]. Hence, the BIPV system serves as a building envelope material and power generator simultaneously [2]. This work summarizes first briefly the current state-of-the-art of BIPV, including both BIPV foil, tiles, modules and solar cell glazing products, also mentioning building attached photovoltaic (BAPV) systems. Thereafter, this work bridges the technologies of today and the scientific explorations of Energies 2016, 9, 21; doi:10.3390/en9010021 www.mdpi.com/journal/energies Energies 2016, 9, 21 2 of 30 tomorrow by addressing and investigating several possible research opportunities and pathways for BIPV in the future. For further overview and elaborations within these aspects of BIPV, refer to the study by Jelle et al. [3]. 2. Building Integration of Photovoltaic Cells Building integration of photovoltaic (PV) cells may be carried out on sloped roofs, flat roofs, facades andEnergies solar 2016 shading, 9, 21 systems. PV cells may be mounted above or onto the existing or traditional Energies 2016, 9, 21 roofing orBIPV wall in systems. the future. OnFor further the other overview hand, and BIPV elaborations systems within replace these theaspects outer of BIPV, building refer to envelope the skin, thus servingstudy simultanously by Jelle et al. [3]. as both a climate screen and a power source generating electricity. That BIPV in the future. For further overview and elaborations within these aspects of BIPV, refer to the is, BIPVstudy may by provide Jelle et al. savings [3]. in materials and labor, in addition to reducing the electricity costs. As 2. 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