Human response to the thermal indoor environment created by a radiant, and a combined radiant and convective cooling system

Ongun B Kazanci,Dolaana Khovalyg,Takayoshi Iida,Tomo-Oki Ukiana,Yoshitaka Uno,Bjarne W Olesen,S.I Tanabe,I Nastase,J Kurnitski,M.C Gameiro Da Silva,H Zhang,G Cao,L Mazzarela,C Inard,P Wargocki

doi:10.1051/e3sconf/201911102060

Abstract

This study reports the main findings from a series of human subject experiments, where the subjects were exposed to the different indoor environments created by different cooling systems. The studied systems were a radiant cooling system (chilled ceiling and mixing ventilation, CCMV), and a combined radiant and convective cooling system (radiant diffuse ceiling ventilation, RDCV). The experiments were conducted in a climate chamber under controlled conditions. The climate chamber was configured as a two-person office room. 24 human subjects (12 female and 12 male) were chosen. The exposure lasted three hours and the participants were allowed to work on their own tasks (normal office work) during the exposure. The cooling load was 54 W/m2 and the room temperature at a reference location was kept constant at 26°C (summer conditions). The results show that under both systems, whole body thermal sensation was between slightly warm and neutral (closer to neutral with the RDCV system), and the overall thermal acceptability was almost the same for both systems (close to clearly acceptable). The satisfaction of the human subjects with the thermal environment was very close under the two systems; between satisfactory and slightly satisfactory (closer to satisfactory). Air movement acceptability (slightly higher and closer to clearly acceptable with the RDCV system) was also very close with the two systems. The results of the human subject experiments agree well with the physical measurements of the thermal indoor environment and confirm that the studied systems created very similar thermal indoor environments.

Highlights

Buildings are often cooled by mechanical cooling systems, which have different energy use characteristics and create different thermal indoor environments
This study reports the main findings from a series of human subject experiments, where the subjects were exposed to the different indoor environments created by different cooling systems
The experiments were conducted in a climate chamber under controlled conditions

Summary

Introduction

Buildings are often cooled by mechanical cooling systems, which have different energy use characteristics and create different thermal indoor environments. The created thermal indoor environment depends strongly on the chosen indoor terminal unit. Indoor terminal units are active building components that emit or remove heat and moisture to indoor spaces. Indoor terminal units mainly rely on convection (natural or forced), radiation or both [1]. Radiant heating and cooling systems have several benefits in terms of energy performance, operation, and thermal comfort, compared to the more conventional convective systems [2]. Due these benefits, the interest in radiant systems and their use is increasing world-wide

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