Conference Agenda

Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).

Session Overview
Poster introductions 20: Building envelope
Wednesday, 25/Aug/2021:
11:40am - 12:00pm

Session Chair: Prof. Staf Roels, KU Leuven
Location: Room 3 - Room 013, Building: 116

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11:40am - 11:43am

Thermal resistance of the ventilated air-spaces behind external claddings; theoretical definition and a parametric study

Mohammad Rahiminejad, Dolaana Khovalyg

École polytechnique fédérale de Lausanne, Switzerland

The presence of a ventilated air cavity between the external cladding and the wall core of a wall assembly can have a varying contribution to the thermal performance of the building envelope. In particular, the thermal resistance of a ventilated air-space is a dynamic parameter that is influenced by various environmental and thermo-physical parameters. In this study, a theoretical definition of the thermal resistance of a ventilated air-space behind an external cladding is introduced, employing a non-linear network of thermal resistances to the entire wall assembly. A numerical code is developed for the steady-state condition and verified with data from hot box tests available in the literature. Thereafter, a parametric analysis based on air change rate in the cavity (0 to 1000 1/h), type of the external cladding (brick and vinyl siding), seasonal variation (summer and winter conditions), presence of the reflective insulation, and roughness of the cavity surfaces is performed. The results are compared with a closed cavity facade to see the efficiency of the ventilation in the air-space. The results confirm that the theoretical thermal resistance of the ventilated air-space is a function of multiple factors, and its magnitude varies under different conditions.

11:43am - 11:46am

Using Closed Cavity Façades (CCF) to enhance building thermal performance

Michalis Michael

University of Cambridge, United Kingdom

Buildings are at the pivotal center of our lives. We spend, on average, 87-90% of our time in buildings. Just as human skin is an all-important barrier and thermal regulator of the human body, the building "skin" is the first critical element in defining goals for building energy performance and occupant comfort. The building envelope has an important and direct effect on its overall performance and whole-life cost. Glazing is particularly critical because it is the most vulnerable envelope part to heat gain and heat loss that account for around 42% of a building’s energy consumption. However, conventional glazing technologies have relatively low-performance characteristics which cause significant heat losses during winter and undesired heat gain in summer. In this regard, this study investigates the thermal and visual performance of CCF glazing technologies of various design configurations, in comparison with traditional glazing technologies. In its simplest form, a CCF consists of a DGU on the inner layer and single glazing on the outer one, forming a sealed non-ventilated cavity with automated blinds in between which, given its dynamic behaviour can contribute to balance the demand for energy saving, thermal, and visual comfort.

Using Energy Plus and IDA ICE, several CCF configurations and geometries were investigated and compared to the baseline (DGU). MATELab, an office-like test facility at the University of Cambridge was used as the model for the simulations, which was beforehand experimentally validated. The results show extensive benefits of CCFs compared to traditional DGU systems in terms of thermal performance and comfort in cold climates (20-23% decrease in annual total energy use and positive effect on thermal comfort with a significant reduction in radiant discomfort). Further investigation showed that glass coatings and solar shading play an important role in cutting down overheating, retaining the cavity temperatures below the critical value.

11:46am - 11:49am

Development of advanced multifunctional façade systems: Thermo-acoustic modelling and performance

Stefano Fantucci, Fabio Favoino, Elisa Fenoglio, Valentina Serra, Marco Perino, Louena Shtrepi, Marta Bivanti, Arianna Astolfi

Politecnico di Torino - Department of Energy

The development of lightweight and multifunctional curtain wall systems, which integrate different technological solutions, is aimed at achieving increasingly higher requirements related to energy efficiency as well as indoor environmental quality in non-residential buildings. On one hand lightweight and thin façade elements present several advantages (such as construction time, space, and transportation savings, less weight on primary structure etc.), while facing the challenge of guaranteeing the required thermal and acoustic performance and to be compliant with the current legislation on the other.

In the framework of the Horizon 2020 Project Powerskin+ a new concept of multifunctional façade which combines high performance insulation, energy harvesting, heating system, and latent heat storage capabilities is under development. Within the design process of the different sub-modules (opaque and transparent), performance calculation are carried out by means of existing simulation tools, or ad-hoc developed models for more complex systems.

In this study, the authors present the main steps to accelerate the simulation based design process and the future thermal and acoustic optimization of the novel lightweight and multifunctional façade element.

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