No abstract

No abstract

Energy performance analysis of Electrochromic (EC) windows is carried out. EC glass and control strategies are modeled and implemented in ESP-r. EC windows are evaluated, on a test prototype, as an alternative to shading devices. Set-points and measured variables are used to control optical properties of EC glass. Within this context, the paper focuses on the energy savings that may occur when using electrochromic (EC) windows, an interesting emerging technology alternative to shading devices to control solar gain in buildings located in Mediterranean climates. The EC windows technology is briefly presented and the optical properties adjustments of the glasses are discussed according to the operated range. The EC window dynamic behavior and the different control strategies are modeled and implemented in the ESP-r building simulation program. The EC window impact in the energy needs for heating and cooling is studied, considering different ambient parameters (exterior dry bulb temperature, interior dry bulb temperature and incident radiation) and set points for the EC control. A comparison of several windows solutions (single, double-glazing and EC windows), the type of building, internal gains from occupancy, lighting and equipment and the orientation of windows are considered for discussion through the analysis of the energy needs for heating and cooling. It is concluded that for this climate the best positive results are obtained when the EC are used in the west façade. For the south façade the results show no significant advantages in using EC windows.

No abstract

No abstract

No abstract

The growing demand for nearly-Zero Energy Buildings is rapidly contributing to change the building skin from being a passive barrier towards a sensitive and active interface. Building Integrated Photovoltaics (BIPV) is a unique solution for delivering clean, safe, affordable and decentralized electricity to people transforming the building surfaces in active solar collectors. Despite photovoltaic (PV) technology and their basic usage are today known to everybody, the particular requirements for building integration have brought to the surface some issues over the years so that BIPV is still a niche market. Starting from this observation, the paper presents the results of an investigation on the current market of BIPV products for roofs and façade. The analysis aimed to identify the relevant possibilities the products today offer and the level of information that the producers make available within the technical description of BIPV systems. After disclosing the actual lack of information in comparison to conventional building products, the authors propose to implement a new "building-based" approach that could support the BIPV market by including a more comprehensive description of the product's quality (today mainly comprising electrical and basic physical features). Such a "building-technology" perspective, also considering the recent normative framework in BIPV field, is expected to encourage the technological transfer of PV in the building sector by facilitating the daily work of architects, installers and the whole value chain.

Rapid and uncontrolled urbanization is continuously increasing buildings’ energy consumption and greenhouse gas emissions into the atmosphere. In this scenario, solar energy integrated into the built environment can play an important role in optimizing the use of renewable energy sources on urban surfaces. Preliminary solar analyses to map the solar accessibility and solar potential of building surfaces (roofs and façades) should become a common practice among urban planners, architects, and public authorities. This paper presents an approach to support urban actors to assess solar energy potential at the neighborhood scale and to address the use of solar energy by considering overshadowing effects and solar inter-building reflections in accordance with urban morphology and building characteristics. The approach starts with urban analysis and solar irradiation analysis to elaborate solar mapping of façades and roofs. Data processing allows assessment of the solar potential of the whole case study neighborhood of Sluppen in Trondheim (Norway) by localizing the most radiated parts of buildings’ surfaces. Reduction factors defined by a new method are used to estimate the final solar potential considering shadowing caused by the presence of buildings’ architectural elements (e.g., glazed surfaces, balconies, external staircases, projections) and self-shading. Finally, rough estimation of solar energy generation is assessed by providing preliminary recommendations for solar photovoltaic (PV) systems suited to local conditions. Results show that depending on urban morphology and buildings’ shapes, PV systems can cover more than 40% of the total buildings’ energy needs in Trondheim.