Thermal behavior analysis of different multilayer façade: Numerical model versus experimental prototype

Abstract

In this paper, different sort of façades have been analyzed considering their thermal behavior along a 24 hours period. A numerical model has been developed and compared with experimental measurements considering two different façades for buildings: on the one side an opaque multilayer façade; and on the other side, a ventilated façade. The numerical model representing the temperature in every layer of the façades has been successfully validated. This model has been used for determining the thermal behavior of two new ventilated façades in which the thermal mass has been changed, observing then than the existence of the moving in the air gap affects particularly the air temperature and the thermal transmittance of the façade when the sun is incising over the façade, leading to a decrease of transmittance close to 30% along the air chamber. This quantification is fundamental in warm climates, where this effect is determinant for decreasing the cooling necessities of buildings in summer with no need of increasing the mass of the façade.

Modelling and simulation of Building-Integrated solar thermal systems: Behaviour of the system

“…The thermal performance of different types of façades over a 24-h period was investigated [48]. A numerical model was developed and compared with experimental data for two different building façades: on one side an opaque multilayer façade; on the other side, a ventilated façade.…”

Lowest thermal transmittance of an external wall under budget, material and thickness restrictions: An integer linear programming approach

“…Mandilaras et al [11] studied the thermal performance during one year of an external wall, considering alternative materials in its different layers. Guillén et al [12] also study the thermal performance of several differently ventilated external walls, along a 24h period, with the aim of, among others, reducing the cooling needs of buildings in summer without increasing the total mass of the façade. Eicker et al [13] present an energetic and economic comparison between energy efficient refurbishment of the building envelope and the integration of renewable solar energy technologies for different climatic conditions.…”

“…The air gap (aG) shows 3 different configurations and 9 options: light ventilated air gap (from 3 to 10 cm), not ventilated air gap (4 options) and absence of air gap. Note that air-gaps play a very important role in thermal insulation but also in moisture control [12]. Nevertheless, the absence of air gap or ventilation is also a common constructive solution for external walls.…”

Experimental Comparison Between Three Types of Opaque Ventilated Facades

“…Their characteristic is the presence of an external cladding anchored to the wall surface of the building through a metal frame, detached from the insulation layer, thus creating a ventilated air gap [1,2]. This multi-layer constructive technology achieves high energy performance with respect to conventional facades [3,4]. The air gap activates an airflow between the lower inlet and the upper exhaust openings driven by the buoyancy effect and the wind force [5].…”