To main content

Impact of convection on thermal performance of aerogel granulate glazing systems

Abstract

Among currently available window systems, aerogel granulate glazing systems are considered promising for achieving good thermal and visual comfort in buildings. In aerogel granulate glazing systems, it is important to evaluate how convection in the granular-filled cavity affects their thermal performance because double glazing systems, which have a similar structure, show variable thermal properties related to the convection effect. In this study, it is shown that the granular-filled cavity hardly influences the air permeance, and therefore, convection can occur in such cavities. Nevertheless, a mock-up of commercially available aerogel granulate window shows practically identical window U-values in hot box measurement with various tilt angles. In other words, convection in the granular cavity does not affect the thermal performance of aerogel granulate glazing systems. The center-of-glass U-values are 0.28 and 0.69 W/(m2 K) for aerogel thickness of 60 and 30 mm, respectively. The total window U-values (using a wood frame) are 0.69 and 0.84 W/(m2 K) for aerogel thickness of 60 and 30 mm, respectively. Furthermore, the granular aerogel in the cavity subsided by ∼3% of its total volume after the hot box measurement. The risks posed by this subsidence under actual conditions should be assessed in later research.

Category

Academic article

Client

  • Research Council of Norway (RCN) / 207551

Language

English

Author(s)

Affiliation

  • Norwegian University of Science and Technology
  • Japan
  • SINTEF Community / Architecture, Materials and Structures

Year

2015

Published in

Energy and Buildings

ISSN

0378-7788

Volume

88

Page(s)

165 - 173

View this publication at Cristin