Development of personalized air supply systems

Pao Yue-kong Library Electronic Theses Database

Development of personalized air supply systems

 

Author: Kwok, Hiu-kwan
Title: Development of personalized air supply systems
Degree: M.Eng.
Year: 2007
Subject: Hong Kong Polytechnic University -- Dissertations.
Air filters.
Air -- Purification -- Equipment and supplies.
Demand controlled ventilation systems.
Department: Dept. of Building Services Engineering
Pages: xiii, 119 leaves : ill. (some col.) ; 30 cm.
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b2117575
URI: http://theses.lib.polyu.edu.hk/handle/200/858
Abstract: Personalized Air Supply (PAS) system is designed to achieve good inhaled air quality, improve thermal comfort and provide individual thermal preferences for occupants. In this study, Chair-based Personalized Air Supply system with Air Terminal Device (AID) located at chin position of occupant was developed. Flexible "Neck goose" support has been designed to provide adjustment of position of the AID in the PAS system. The Chair-based Personalized Air Supply system is expected to be applicable to many other built environments. The objective of this study is to investigate the performance of air quality, thermal comfort and human acceptability of the improved Chair-based PAS system by experimental measurements and subjective surveys. In experimental measurements, a thermal manikin was used to simulate a human being. Tracer gas was used to evaluate the amount of personalized air inhaled by the manikin. Six experimental conditions at ambient temperature of 24oC and PAS supply temperature of 22oC and 24oC were designed to perform in the experiments. Flow rate of PAS was changed from 0.8L/S to 1.61/s. Two indices, Pollution Exposure Reduction effectiveness and Fresh Air Utilization Efficiency, were applied to analyze quality of inhaled air and system effectiveness. The Pollution Exposure Reduction effectiveness increased with the increase of the PAS flow rate. 53.6% of Pollution Exposure Reduction effectiveness was achieved at PAS flow rate of 1.6L/S under isothermal condition. In contrast, the Fresh Air Utilization Efficiency decreased with increase of the flow rate. The maximum Fresh Air Utilization Efficiency of 6.8% was obtained at PAS flow rate at 0.81/s also under isothermal condition. In addition to physical experiments, subjective surveys were conducted to assess human responses on different thermal conditions created by the PAS system. 30 human subjects participated in the survey. During the survey, perceived air quality, feelings of irritation, thermal sensation, thermal acceptability, as well as temperature and flow rate preferences were studied under nine experimental conditions as in the physical experiments. Significant improvement in the perceived air quality was obtained when PAS system was operated, compared to the case with mixing ventilation alone. High PAS flow rate can ensure larger amount of personalized air in the inhalation as proved in the experimental measurements; however, the survey results indicate that at such a high flow rate, draught discomfort was experienced by the subjects. The optimum condition would be at 0.8L/s under PAS temperature 22oC and 24oC, in which the air quality and thermal environment perceived are the most acceptable. The thermal sensations were reported at the ranged of the "Neutral" and "Less Irritation" feelings from the subjects. Most of the subjects preferred no change to the environment. Compared with the Mixing ventilation system alone, it can be found that the additional installation of the PAS system can improve the perceived air quality and the thermal sensation to the user at particular thermal condition. Recommendations for investigating the free convection flow and the personalized air flow interaction and identifying the minimum flow rate that obtains steady maximum effectiveness are given. Obtaining an extensive response to thermal acceptability of the PAS system from different age groups and genders is also suggested in the further studies. Future research needed on the development of the PAS system is outlined in the dissertation.

Files in this item

Files Size Format
b21175755.pdf 13.30Mb PDF
Copyright Undertaking
As a bona fide Library user, I declare that:
  1. I will abide by the rules and legal ordinances governing copyright regarding the use of the Database.
  2. I will use the Database for the purpose of my research or private study only and not for circulation or further reproduction or any other purpose.
  3. I agree to indemnify and hold the University harmless from and against any loss, damage, cost, liability or expenses arising from copyright infringement or unauthorized usage.
By downloading any item(s) listed above, you acknowledge that you have read and understood the copyright undertaking as stated above, and agree to be bound by all of its terms.

     

Quick Search

Browse

More Information