The Prediction of the Leakage Airflow Rate Using the Supply and Return Airflow Rate in a Variable Air Volume System

Pressure differences in the envelope of a building result in leakage airflow (i.e., the unintended flow of air). This can lead to increased building heating and cooling energy, decreased thermal comfort for occupants, and the spread of moisture. To address this problem, it is necessary to know the l...

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Main Authors: Kyung-Won Kim, Hyo-Jun Kim, Jin-Hyun Lee, Young-Hum Cho
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/14/22/10363
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author Kyung-Won Kim
Hyo-Jun Kim
Jin-Hyun Lee
Young-Hum Cho
author_facet Kyung-Won Kim
Hyo-Jun Kim
Jin-Hyun Lee
Young-Hum Cho
author_sort Kyung-Won Kim
collection DOAJ
description Pressure differences in the envelope of a building result in leakage airflow (i.e., the unintended flow of air). This can lead to increased building heating and cooling energy, decreased thermal comfort for occupants, and the spread of moisture. To address this problem, it is necessary to know the leakage airflow in a building. Generally, the leakage airflow in a building is calculated by determining the leakage function through fan pressurization methods, such as the blower door test, and substituting the pressure difference measured by the pressure sensor. However, it is difficult to install continuous pressure sensors in an operating building. Therefore, this study proposes a method to utilize the supply and return airflow of an air conditioning system to predict the variation in the leakage airflow with changing indoor and outdoor airflow, and the efficacy of this approach was verified through experiments. The experiment measured the indoor and outdoor pressure difference of the building with a change in the speed of the supply and return fans and the opening rate of the variable air volume (VAV) damper. As a result of the experiment, the indoor–outdoor pressure difference is proportional to the difference between the indoor supply airflow and the ventilation airflow. In addition, the relationship between the pressure difference and the leakage airflow was derived through the pressurization/decompression method using an air handler, and the leakage airflow from the pressure difference generated by the operation of the air conditioning system was calculated. Lastly, the relationship between the supply and return airflow difference and the leakage airflow was derived based on the experimental results, and the leakage airflow was predicted based on the relationship.
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spelling doaj-art-92a436e867a34062aaba8fa30a39c8d12025-08-20T01:53:43ZengMDPI AGApplied Sciences2076-34172024-11-0114221036310.3390/app142210363The Prediction of the Leakage Airflow Rate Using the Supply and Return Airflow Rate in a Variable Air Volume SystemKyung-Won Kim0Hyo-Jun Kim1Jin-Hyun Lee2Young-Hum Cho3Department of Architectural Engineering, Graduate School of Yeungnam University, Gyeongsan 38541, Republic of KoreaR&D Center, BETECH, Daegu 41228, Republic of KoreaArchitecture Research Institute, Yeungnam University, Gyeongsan 38541, Republic of KoreaSchool of Architecture, Yeungnam University, Gyeongsan 38541, Republic of KoreaPressure differences in the envelope of a building result in leakage airflow (i.e., the unintended flow of air). This can lead to increased building heating and cooling energy, decreased thermal comfort for occupants, and the spread of moisture. To address this problem, it is necessary to know the leakage airflow in a building. Generally, the leakage airflow in a building is calculated by determining the leakage function through fan pressurization methods, such as the blower door test, and substituting the pressure difference measured by the pressure sensor. However, it is difficult to install continuous pressure sensors in an operating building. Therefore, this study proposes a method to utilize the supply and return airflow of an air conditioning system to predict the variation in the leakage airflow with changing indoor and outdoor airflow, and the efficacy of this approach was verified through experiments. The experiment measured the indoor and outdoor pressure difference of the building with a change in the speed of the supply and return fans and the opening rate of the variable air volume (VAV) damper. As a result of the experiment, the indoor–outdoor pressure difference is proportional to the difference between the indoor supply airflow and the ventilation airflow. In addition, the relationship between the pressure difference and the leakage airflow was derived through the pressurization/decompression method using an air handler, and the leakage airflow from the pressure difference generated by the operation of the air conditioning system was calculated. Lastly, the relationship between the supply and return airflow difference and the leakage airflow was derived based on the experimental results, and the leakage airflow was predicted based on the relationship.https://www.mdpi.com/2076-3417/14/22/10363building pressure differenceleakage airflow ratesupply and return airflow ratebuilding airtightness
spellingShingle Kyung-Won Kim
Hyo-Jun Kim
Jin-Hyun Lee
Young-Hum Cho
The Prediction of the Leakage Airflow Rate Using the Supply and Return Airflow Rate in a Variable Air Volume System
Applied Sciences
building pressure difference
leakage airflow rate
supply and return airflow rate
building airtightness
title The Prediction of the Leakage Airflow Rate Using the Supply and Return Airflow Rate in a Variable Air Volume System
title_full The Prediction of the Leakage Airflow Rate Using the Supply and Return Airflow Rate in a Variable Air Volume System
title_fullStr The Prediction of the Leakage Airflow Rate Using the Supply and Return Airflow Rate in a Variable Air Volume System
title_full_unstemmed The Prediction of the Leakage Airflow Rate Using the Supply and Return Airflow Rate in a Variable Air Volume System
title_short The Prediction of the Leakage Airflow Rate Using the Supply and Return Airflow Rate in a Variable Air Volume System
title_sort prediction of the leakage airflow rate using the supply and return airflow rate in a variable air volume system
topic building pressure difference
leakage airflow rate
supply and return airflow rate
building airtightness
url https://www.mdpi.com/2076-3417/14/22/10363
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