# Photovoltaics on Landmark Buildings with Distinctive Geometries
## 1 Introduction  
The use of photovoltaics (PV) has registered a significant increase in the last decades, because of their higher efficiency and a rapid drop in their prices [1]. As most countries try to tackle their energy security problems and reduce greenhouse gas emissions [2], new policies are implemented to increase the distributed generation of energy in the built environment [3]. Towards that end, the use of PVsystems in landmark buildings, either private or public, represent virtuous examples for a broader impact to society and investors. \"Buildings occupied by public authorities and buildings frequently visited by the public should set an example by showing that environmental and energy considerations are being taken into account\" [3]. Furthermore, the use of PVs in these buildings can inspire architects and PV practitioners to move past the aesthetically neutral, towards a visually attractive element in an architectural context [4]. Landmark buildings are recognized easily in their built environment, by their size, shape, social importance, funds invested, etc. [5]. They range from constructions with high heritage and historical value (e.g., cathedrals, museums and government buildings) to contemporary architectures, such as stadiums, concert halls, exhibition centres, educational centers, public buildings, headoffices, etc. [6]. To that end, the exploitation of renewable energy sources in historical and heritage buildings has been extensively studied [7]. Some researchers proposed methodologies for retrofitting measures to improve the energy performance of historical buildings [8] and studied the integration of solar facades in buildings in the eastern Mediterranean [9]. Other researchers focused on the analysis of the energy saving potential in historical buildings in Europe as a source of national energy savings and building reuse improvement [10], assessing the energy performance and the costs of energy retrofitting and technological renovation of historical buildings without affecting their historic and architectural qualities [11], or towards achieving net zero energy classification [12]. Besides technical performance that has been extensively examined [2; 13; 14], the architectural aesthetic values, visibility and integration of PV are important aspects for the promotion and application of solar energy conversion systems in buildings integrated elements [15]. Firstly, practitioners need to consider the architectural value of integrated PV systems in buildings; secondly, architects should exploit the adoption of PVs on exceptional architectural examples; thirdly, contemporary investors of remarkable architectural buildings in terms of financial background of PV application, should consider the environmental impact and on the society [16]. This aspect was only recently considered by researchers on the dynamics of the transition of urban areas from traditional to sustainable and smart neighbourhoods [17] by investigating the context of cities with well-known traditions of sustainable urban development. This drive towards PV integration in landmark buildings is not limited to specific geographical boundaries, but is shared worldwide, as attested in the literature [16; 18; 19]. In this paper, ten landmark buildings are considered, based on a number of parameters like PV integration, geometry and visibility, size and shape and architectural value. The motivation of the study is to bridge the architectural design with the PV engineering, aiming at highlighting the architectural performance of PV integration systems in landmark buildings, which have significant dimensions and importance in the society.