The comfort and energy impact of overcooled buildings in warm climates

Research output: Contribution to journalArticlepeer-review

Abstract

Around 18% of global carbon emissions can be attributed to building heating or cooling, driven by the adoption of “international” thermal comfort standards such as ASHRAE-55, which imply an homogenous indoor environment. We argue that the importation of such standards to warm climates results in indoor cold discomfort due to “overcooling”: a phenomenon anecdotally recognised worldwide but not studied or defined systematically. Unlike under- or over-heating, overcooling is the purposeful over-expenditure of energy, that creates conditions of cold thermal discomfort. We examine data for warm and temperate climates from a global thermal comfort database spanning 27 countries with over 90,000 occupant responses to investigate overcooling of air-conditioned buildings. We suggest that overcooling is best defined by taking the intersection of thermal sensation and preference and, using this definition, we find that 17% of building occupants in the examined data can be classed as being overcooled. We estimate the cooling energy demand of overcooling imposed through the adoption of the ASHRAE-55 standard using computer simulations that move building occupants from being overcooled to comfortable. The results suggest around 15% of cooling energy demand could be saved through a simple upward adjustment of set-point temperatures by 2 °C in warm climates. Such an adjustment in the Global South, which contains the majority of the warm regions of the Earth, could have a dramatic impact on the evolution of future cooling energy demand which is expected to triple by 2050.

Original languageEnglish
Article number111938
JournalEnergy and Buildings
Volume260
Early online date12 Feb 2022
DOIs
Publication statusPublished - 1 Apr 2022

Keywords

  • Building energy
  • Building overcooling
  • Cold thermal discomfort
  • Thermal comfort
  • Warm and hot climates

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Building and Construction
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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