Journal article
Stability and accuracy of variable air volume box control at low flows. Part 1: Laboratory test setup and variable air volume sensor test
HVAC&R research, v 20(1), pp 3-18
01 Jan 2014
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
Variable air volume systems with direct digital controllers have been widely adopted in the HVAC system of commercial, industrial, and large residential buildings because they provide better energy efficiency and occupant comfort. Normally, a variable air volume terminal unit defines a minimum airflow rate to satisfy the space ventilation requirement and/or the proper operation of a terminal heating coil, if so equipped. However, it has been found that variable air volume terminal units often fail to perform as expected at the minimum airflow range (below 500 fpm [2.5m/s]). Under such a flow range, the embedded airflow sensor becomes inaccurate, and the designed minimum airflow rate is less than the minimum controllable airflow rate. This results in a series of problems, including lack of ventilation, uneven airflow control, reduced damper and operator life, and energy waste. Through designed laboratory and field tests, this study (ASRHAE Research Project RP-1353) aims to identify the major factors that cause inaccuracy and instability issues in variable air volume terminal units and the relationship between the major factors and performance of the airflow sensor, controller, and terminal unit system. Laboratory tests performed in this study included a variable air volume sensor test, controller test, and system test. Four variable air volume boxes from three manufacturers and four controllers from four manufacturers were tested systematically. Two identical test beds with high accuracy (+/- 0.5%) reference airflow meters were designed and constructed in the test facility. The size of the reference airflow measuring stations was carefully selected to provide maximum airflow measuring accuracy and maximum available system pressure drop. This article describes the laboratory test setup and summarizes the variable air volume sensor test results. A companion article summarizes the controller test, system test, and field test results. From the variable air volume sensor test, three factors, namely, inlet conditions, low variable air volume damper positions, and low airflow rates, are identified as strongly impacting variable air volume terminal unit performance.
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Details
- Title
- Stability and accuracy of variable air volume box control at low flows. Part 1: Laboratory test setup and variable air volume sensor test
- Creators
- Ran Liu - Department of Civil, Architectural and Environmental Engineering , Drexel University , Philadelphia , PA , USA ; Iowa Energy Center Energy Resource Station, 2006 S. Ankeny Blvd., DMACC Building #23 , Ankeny , IA , 50023 , USAJin Wen - Drexel UniversityXiaohui Zhou - Iowa Methodist Medical CenterCurtis Klaassen - Iowa Energy Center Energy Resource Station, 2006 S. Ankeny Blvd., DMACC Building #23 , Ankeny , IA , 50023 , USA ; Energy Systems Engineering , Adel , IA , USA
- Publication Details
- HVAC&R research, v 20(1), pp 3-18
- Publisher
- Taylor & Francis
- Number of pages
- 16
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Civil, Architectural, and Environmental Engineering
- Web of Science ID
- WOS:000330022200002
- Scopus ID
- 2-s2.0-84893064567
- Other Identifier
- 991019168351804721
UN Sustainable Development Goals (SDGs)
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InCites Highlights
Data related to this publication, from InCites Benchmarking & Analytics tool:
- Web of Science research areas
- Construction & Building Technology
- Engineering, Mechanical
- Thermodynamics