Transforming thermal-radiative study of a climber green wall to innovative engineering design to enhance building-energy efficiency

Shing Him Louis LEE, Chi Yung JIM

Research output: Contribution to journalArticle

Abstract

The thermo-regulatory function of building-integrated climber vegetation has been verified. However, there is a need to increase in-situ observation studies on green walls installed on windowed building envelopes. This study presents results of instrumental monitoring of the thermal and radiative environment of a climber-green wall with windows to inspire a more energy-efficient green wall system design. This research is based in humid-subtropical Hong Kong, with reference to experimental controls (without vegetation cover) of a bare wall and a bare roof in sunny, cloudy and rainy weather in summer. The experimental results demonstrated lower short-wave reflectivity on green wall (0.13) than on control bare wall (0.30). Green wall received the thermal influence of long-wave terrestrial radiation as well as sky radiation. On sunny, cloudy and rainy days, the exterior concrete wall surface behind climber vegetation was cooler than control bare wall up to 6.6, 2.3 and 1.2 K respectively, and the posterior air gap shielded by the climbers was cooler than ambient air up to 2.2, 0.8 and 0.4 K. On sunny day, indoor wall surface and air of the green wall envelope were warmer at maximum by 1.4 and 1.3 K respectively, possibly contributed by the thermal bridge effect of the windows. On cloudy and rainy days, however, indoor surface and air experienced cooling by < 2.0 K. The evaluation of the thermal effects of windows on the indoor thermal regime led to the proposal of a rotatable green wall planter system, which could optimize daytime and nighttime thermal benefits by maximizing daytime shading-induced shielding against through-window insolation and nighttime radiative heat loss. Copyright © 2019 Elsevier Ltd. All rights reserved.
Original languageEnglish
Pages (from-to)892-904
JournalJournal of Cleaner Production
Volume224
Early online dateMar 2019
DOIs
Publication statusPublished - Jul 2019

Fingerprint

energy efficiency
Energy efficiency
engineering
Air
Radiation
Incident solar radiation
Heat losses
Shielding
Thermal effects
Roofs
Systems analysis
Hot Temperature
Engineering design
Concretes
air
Cooling
Monitoring
vegetation
thermal regime
shading

Citation

Lee, L. S. H., & Jim, C. Y. (2019). Transforming thermal-radiative study of a climber green wall to innovative engineering design to enhance building-energy efficiency. Journal of Cleaner Production, 224, 892-904. doi: 10.1016/j.jclepro.2019.03.278

Keywords

  • Climber green wall
  • Window effect
  • Thermal benefit
  • Wall surface shielding
  • Air gap cooling
  • Rotatable green wall planter