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Net Zero-Energy Buildings (NZEBs) have received increased attention in recent years as a result of constant concerns about energy supply constraints, decreasing energy resources, increasing energy costs and the rising impact of greenhouse gases on world climate. Promoting whole building strategies that employ passive measures together with energy efficient systems and technologies using renewable energy became a European political strategy following the publication of the Energy Performance of Buildings Directive recast in May 2010 by the European Parliament and Council. However designing successful NZEBs represents a challenge because the definitions are somewhat generic while assessment methods and monitoring approaches remain under development and the literature is relatively scarce about the best sets of solutions for different typologies and climates likely to deliver an actual and reliable performance in terms of energy balance (consumed vs generated) on a cost-effective basis. Additionally the lessons learned from existing NZEB examples are relatively scarce. The authors of this paper, who are participants in the IEA SHC Task 40-ECBCS Annex 52, “Towards Net Zero Energy Solar Buildings”, are willing to share insights from on-going research work on some best practice leading NZEB residential buildings. Although there is no standard approach for designing a Net Zero-Energy Building (there are many different possible combinations of passive and efficient active measures, utility equipment and on-site energy generation technologies able to achieve the net-zero energy performance), a close examination of the chosen strategies and the relative performance indicators of the selected case studies reveal that it is possible to achieve zero-energy performance using well known strategies adjusted so as to balance climate driven-demand for space heating/cooling, lighting, ventilation and other energy uses with climate-driven supply from renewable energy resources.

The purpose of this paper is to present a critical review of the key trends in the integration of photovoltaic (PV) facilities into the built environment in cities. This is regarded as part of a series of measures towards wider use of renewable energy sources.

The problem has been approached from the point that cities are consumers of large amounts of energy. They require uninterrupted energy supply but with dynamic power profile. Mainly consumption of energy generated from fossil fuels is present nowadays with significant pollution of the environment as a consequence. The sustainable energy transition in cities means increasing the supply of energy from renewable sources.

The paper points to the integration of PV renewable systems in the built environment, opportunities and constraints, design conditions and tools. The consideration of the constraints which creates urban environment is carried out to understand the complexity of selecting locations in the cities. The paper gives an overview of the possibilities of PV systems integration in the built environment and discusses physical limitations in the urban environment and simulation tools as well as challenges and research and development issues.

The paper offers a critical review of the PV applications which have been illustrated with examples from developed countries. However, examples from developing markets have not been considered. Future work would address this limitation and enable the discussion from a comparative perspective.

The study gives a comprehensive overview of PV integrations in contemporary cities, stimulating architects’ practitioners to acquire the PV technology and aesthetics, and to apply it in future developments.

Observing the use of PV applications from the perspective of architects and designers the discussion and examples covered in this paper offers an original review, which provides the base future in-depth studies on PV applications in various contexts.