Description

People working in a hot humid environment are exposed to heat strains due to the high ambient conditions as well as hindered cooling by sweat evaporation from the human body. This causes heat accumulation in the human body and an increase in the core temperature affecting the comfort of the workers and eventually their productivity. Passive cooling vests containing phase change material (PCM) have been designed to provide cooling for the body. However, the presence of PCM packets creates a barrier in the path of sweat evaporation, and in humid conditions, condensation might happen on the surface of the packets. A combination of PCM and solid desiccant packets was used to minimize the risk of condensation and provide a drier microclimate in the cooling vest. The aim of this study is to integrate a validated fabric-PCM-Desiccant model with a validated Bioheat model and assess the human thermal response upon wearing the PCM-Desiccant vest.The fabric-PCM-Desiccant model is based on heat and mass balances that predict fabric, PCM, desiccant and micro and macro climate air temperatures, as well as micro and macro climate air humidity contents. The bioheat model divides the human body into 25 segments including upper and lower segments of the trunk, that are represented by 8 skin nodes. The bioheat model predicts segmental skin temperatures and heat losses, as well as, mean skin and core temperatures and sweat rate. Thus, an integrated model would allow designing a PCM-Desiccant cooling vest capable of sufficiently cooling the body while maintaining a drier microclimate. The integrated model would also allow assessing the effect of the PCM-Desiccant vest on skin temperature, microclimate temperature, and microclimate humidity content.In this study, a comparison is done between predicted skin and microclimate temperatures and microclimate humidity content when using a PCM-Desiccant vest and when using a PCM-Only cooling vest in hot humid conditions. Then, the effect of different PCM melting temperatures on the human thermal responses and the performance of the PCM-Desiccant vest is examined to give a recommended vest design. It is expected that the PCM-Desiccant cooling vest would provide a cool and less humid microclimate than that in a PCM-Only cooling vest, thus improving thermal comfort of the worker in hot humid environments.Key-words: Bioheat modeling, fabric-PCM-Desiccant modeling; cooling vest; PCM melting temperature.

Citation: 3rd Intl Conf: Efficient Bldg Design

Product Details

Published:

2018

Number of Pages:

9

Units of Measure:

Dual

File Size:

1 file , 860 KB

Product Code(s):

D-ICEB18-C017