Assessment of virtual thermal manikins for thermal comfort numerical studies. Verification and validation

Cristiana Croitoru,Ilinca Nastase,Florin Bode,Mihnea Sandu

doi:10.1080/23744731.2021.1916379

Abstract

In turbulent flows as in HVAC applications, the fluctuation of air speed can affect the sensation of thermal comfort. This study is a part of a larger experimental and numerical campaign intended to evaluate the influence of the turbulence intensity at the inlet of air distribution systems on the local draft sensation and thermal discomfort for different ventilation cases using numerical simulations. For five different imposed values of turbulence intensity (0%, 3%, 10%, 30%, 50%) the local heat loss for different body parts was quantified CFD simulations were performed using a realistic model of human body along with an experimental validation with a humanoid thermal manikin. The CFD model was further exploited for several cases to evaluate the influence of turbulence intensity on the comfort indicators and local heat loss. The recorded velocity, turbulence and temperature fields allowed us to estimate the distributions of DR, PPD and PMV indexes which showed no significant changes, but correlations were found for the imposed turbulence intensity and local heat loss on different body parts, indicating the influence on thermal perception.

Highlights

Heating Ventilating Air Conditioning (HVAC) systems have to ensure clean air and to maintain comfortable conditions for their users as in the industrialised countries people spend up to 90% of their time indoors [1]
The reduced air mass flows being introduced in the occupied zone, should uniformly distribute fresh air and conditioning cooling or heating loads in order to achieve thermal comfort and acceptable air quality
During our research study we ran computational fluid dynamics (CFD) simulations using a realistic model of human body along with an experimental validation

Summary

Introduction

Heating Ventilating Air Conditioning (HVAC) systems have to ensure clean air and to maintain comfortable conditions for their users as in the industrialised countries people spend up to 90% of their time indoors [1]. The reduced air mass flows being introduced in the occupied zone, should uniformly distribute fresh air and conditioning cooling or heating loads in order to achieve thermal comfort and acceptable air quality. Innovative diffusers should be designed to improve mixing. The improved mixing will logically lead to a more stable flow and to a uniform distribution of the thermal load and will improve the air quality. This is not sufficient if an adequate air diffusion strategy is not implemented in the same time [3]

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Methods

Results