Francesco Frontini

BIPV: building envelope solutions in a multi-criteria approach. A method for assessing life-cycle costs in the early design phase

ABSTRACT The increasing demand for nearly zero energy buildings is rapidly contributing to changing the design criteria in architecture and concept of the building envelope. Today, photovoltaics (PV) is one of the most reliable technologies for integration in the built environment, and building-integrated photovoltaics (BIPV) is introducing a different notion of ‘energy integrability’ into practice. The difficulty of undertaking, from the first design stages, a really integrative approach towards energy (PV and building requirements) is today still one of the strongest barriers to the rise of the BIPV market. Likewise, the same uncertainty affects the economic aspects, objects of this paper, since BIPV systems are often evaluated similar to conventional installations. The typical consequence is to neglect their added value such as the multi-functionality of the system and therefore showing limited advantages of BIPV. Scope of this paper, starting from a multi-criteria approach, is to outline a new methodology for evaluating the cost-effectiveness of BIPV for the building skin. This method, based on a life-cycle costing approach and on the assessment of the whole building envelope solution, is expected to support architects during the early design phase in the research of the optimal design of BIPV, synergistically taking into account both PV and building quality. A comparison with conventional building elements and different PV technologies is also presented in order to strengthen the impact of the proposed methodology.

The impact of electrochromic windows on the energy performance of buildings in Mediterranean climates: a case study

Abstract The process of building rehabilitation is usually strongly constrained regarding morphological changes, particularly in the cases of historic or classified buildings. Therefore, in the present chapter the emerging technology of electrochromic (EC) windows is studied, using building energy simulation to assess the effects on energy efficiency in buildings. The phenomena associated with the current state of EC device technology are described, and their potential future trends are discussed. The validation of control procedures for commercially available EC windows is carried out using the ESP-r simulator, using a case study building to be rehabilitated (Faculty of Arts and Humanities, University of Coimbra) through the analysis of the impact of EC technology on energy consumption and thermal comfort. The methodology designed to assess the use of EC windows begins with the calculation, through simulation for a reference case with single glazing windows, of the solar gains and the internal gains of each space, for both heating and cooling seasons, followed by the estimation of the energy savings that result from the application of EC windows. From the results it is concluded that EC windows are an effective solution to the problems associated with the control of solar gain in the east and west facades. The use of EC windows will reduce the annual energy needs, which is clearly an advantage in the cooling season. Generally, it is concluded that the use of EC windows must be defined according to the type of building, or even space, particularly depending on the occupation and the overall internal gains, on the facade characteristics, orientation, and the shading influence of neighboring buildings.

BIPV Products for Façades and Roofs: a Market Analysis

In this paper, the authors report on a jointly conducted analysis of the current status of the BIPV market starting from a comprehensive overview on the available product, discussing the application ranges and finally by giving the price levels. For this purpose a market survey was conducted among the various stakeholders in the BIPV sector, including architects, installers and BIPV product suppliers. The product survey was conducted for the general European Market and the price survey concerned only Benelux and Swiss markets. The most frequent products analysed were PV tiles and in-roof mounting systems (for residential roofs). Although crystalline silicon technology was most commonly used, thin film technologies gained considerable share in facade products. The data from the price survey showed that new buildings using BIPV products can be executed at very similar costs than projects involving conventional and/or building applied PV products.

Outdoor Characterization of Innovative BIPV Modules for Roof Application

In the framework of the European project Construct PV, two different real scale roof mock-up have been installed, one at SUPSI campus in Lugano (Switzerland) and one at Tegola Canadese Headquarter in Vittorio Veneto (Italy). Purpose of this paper is the investigation of the BIPV solar shingle developed within the project that consists of a durable laminated PV glass (containing crystalline solar cells) integrated onto a waterproofing back membrane bitumen-based with the aim of ensuring an easy-mounting and on-site customization. The test-facilities are aimed to demonstrate and to show the Construct PV technology (visits, professional development and student’s training, etc.) as well as to monitor the main energy performance of the new BIPV shingle in comparison to other BIPV roof systems already on the market. Electrical BIPV performances (energy production, performance ratio, temperature of modules, etc.) and some building performances (watertightness, temperatures, ventilation, etc.) are analyzed and discussed, showing strengths and weaknesses of the technology in a multicriteria perspective involving both energy and constructive requirements. This paper presents the preliminary achievements of the monitoring campaign carried out during the first months of installation.

Palazzo Positivo: Renovation of a Residential Building in Switzerland with BIPV Facades

The paper presents the refurbishment of a residential building located in Chiasso (Switzerland) fully covered by photovoltaic modules. The eight storey apartment house was built in 1965 and after 45 years it was decided, due to its bad condition, to refurbish it. The building owner has set itself the target to totally renovate the building and to achieve the passive house standard. At the beginning of the construction phase, the builders put the goals even higher, deciding that by the use of BIPV modules to the entire facades they can achieve the Plus energy house standard (netZero Energy building). The renovation ended in November 2013. Beside the BIPV facades, a single-axis tracking photovoltaic plant was also installed on the pergola roof terrace in October of 2013 as a last resort. This paper describes the building before and after renovation and discusses the critical points in the planning phase and during construction. Moreover, in order to assess the mechanical stability of the glass-glass a-Si module assembly on the facade, mechanical stress tests were performed in the SUPSI laboratories, which are explained in detail in this paper together with an accurate raytracing analysis (based on RADIANCE tool simulation) done to optimize the BIPV module strings and consequently to increase the energy production on an annual basis.

PV and Façade Systems for the Building Skin. Analysis of Design Effectiveness and Technological Features

Facades are the central element in the design and architectural definition of contemporary buildings. Several solutions, with different aesthetical appeal, perform the finishing materials of existing building and new constructions. A sustainable design process today is intended to produce high-performance buildings that are energy-efficient, healthy and economically feasible, by wisely using renewable resources to minimize the impact on the environment and to reduce, as much as possible, the energy demand. For this reason, the facade system plays an important role for achieving these energy and environmental goals and Photovoltaic can play a leading role in this challenge. Relying on a vast database of products and building examples, collected in different research projects, a multi-criteria analysis has been performed to compare BIPV solutions with other technological possibilities for facade (either traditional than innovative), in terms of technological, architectural, energetic, environmental and economic requirements. As this study demonstrates, PV will be able to become an affordable alternative to conventional facades since a more precise information and a common language will be implemented and shared.