Uncertainty analysis for a virtual flow meter using an air-handling unit chilled water valve

Li Song, Gang Wang, Michael R. Brambley

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

A virtual water flow meter is developed that uses the chilled water control valve on an air-handling unit as a measurement device. The flow rate of water through the valve is calculated using the differential pressure (DP) across the valve and its associated coil, the valve command, and an empirically determined valve characteristic curve. Thus, the uncertainty in the measurements could be significantly greater than for conventional hardware flow meters. In this article, mathematical models are developed and used to conduct uncertainty analyses for the virtual flow meter, and the results from the virtual meter are compared to measurements made with an ultrasonic flow meter. Theoretical uncertainty analysis shows that the total uncertainty in flow rates from the virtual flow meter is 1.46% with 95% confidence; comparison of virtual flow meter results with measurements from an ultrasonic flow meter yielded an uncertainty of 1.46% with 99% confidence. The comparable results from the theoretical uncertainty analysis and empirical comparison with the ultrasonic flow meter corroborate each other and tend to validate the approach to computationally estimating uncertainty for virtual sensors introduced in this study. Furthermore, the results show that the total uncertainty in flow rates from this virtual flow meter is adequately low for use in place of common physical flow meters for monitoring thermal energy use in air handlers and detecting operational and equipment faults that affect energy consumption.

Original languageEnglish
Pages (from-to)335-345
Number of pages11
JournalHVAC and R Research
Volume19
Issue number3
DOIs
StatePublished - Apr 3 2013

Fingerprint

Uncertainty analysis
Water
Air
Ultrasonics
Flow rate
Thermal energy
Uncertainty
Energy utilization
Mathematical models
Hardware

ASJC Scopus subject areas

  • Building and Construction

Cite this

Uncertainty analysis for a virtual flow meter using an air-handling unit chilled water valve. / Song, Li; Wang, Gang; Brambley, Michael R.

In: HVAC and R Research, Vol. 19, No. 3, 03.04.2013, p. 335-345.

Research output: Contribution to journalArticle

@article{7ced2437a2514dca94ed1a9561472ea3,
title = "Uncertainty analysis for a virtual flow meter using an air-handling unit chilled water valve",
abstract = "A virtual water flow meter is developed that uses the chilled water control valve on an air-handling unit as a measurement device. The flow rate of water through the valve is calculated using the differential pressure (DP) across the valve and its associated coil, the valve command, and an empirically determined valve characteristic curve. Thus, the uncertainty in the measurements could be significantly greater than for conventional hardware flow meters. In this article, mathematical models are developed and used to conduct uncertainty analyses for the virtual flow meter, and the results from the virtual meter are compared to measurements made with an ultrasonic flow meter. Theoretical uncertainty analysis shows that the total uncertainty in flow rates from the virtual flow meter is 1.46{\%} with 95{\%} confidence; comparison of virtual flow meter results with measurements from an ultrasonic flow meter yielded an uncertainty of 1.46{\%} with 99{\%} confidence. The comparable results from the theoretical uncertainty analysis and empirical comparison with the ultrasonic flow meter corroborate each other and tend to validate the approach to computationally estimating uncertainty for virtual sensors introduced in this study. Furthermore, the results show that the total uncertainty in flow rates from this virtual flow meter is adequately low for use in place of common physical flow meters for monitoring thermal energy use in air handlers and detecting operational and equipment faults that affect energy consumption.",
author = "Li Song and Gang Wang and Brambley, {Michael R.}",
year = "2013",
month = "4",
day = "3",
doi = "10.1080/10789669.2013.774890",
language = "English",
volume = "19",
pages = "335--345",
journal = "Science and Technology for the Built Environment",
issn = "2374-4731",
publisher = "Taylor and Francis Ltd.",
number = "3",

}

TY - JOUR

T1 - Uncertainty analysis for a virtual flow meter using an air-handling unit chilled water valve

AU - Song, Li

AU - Wang, Gang

AU - Brambley, Michael R.

PY - 2013/4/3

Y1 - 2013/4/3

N2 - A virtual water flow meter is developed that uses the chilled water control valve on an air-handling unit as a measurement device. The flow rate of water through the valve is calculated using the differential pressure (DP) across the valve and its associated coil, the valve command, and an empirically determined valve characteristic curve. Thus, the uncertainty in the measurements could be significantly greater than for conventional hardware flow meters. In this article, mathematical models are developed and used to conduct uncertainty analyses for the virtual flow meter, and the results from the virtual meter are compared to measurements made with an ultrasonic flow meter. Theoretical uncertainty analysis shows that the total uncertainty in flow rates from the virtual flow meter is 1.46% with 95% confidence; comparison of virtual flow meter results with measurements from an ultrasonic flow meter yielded an uncertainty of 1.46% with 99% confidence. The comparable results from the theoretical uncertainty analysis and empirical comparison with the ultrasonic flow meter corroborate each other and tend to validate the approach to computationally estimating uncertainty for virtual sensors introduced in this study. Furthermore, the results show that the total uncertainty in flow rates from this virtual flow meter is adequately low for use in place of common physical flow meters for monitoring thermal energy use in air handlers and detecting operational and equipment faults that affect energy consumption.

AB - A virtual water flow meter is developed that uses the chilled water control valve on an air-handling unit as a measurement device. The flow rate of water through the valve is calculated using the differential pressure (DP) across the valve and its associated coil, the valve command, and an empirically determined valve characteristic curve. Thus, the uncertainty in the measurements could be significantly greater than for conventional hardware flow meters. In this article, mathematical models are developed and used to conduct uncertainty analyses for the virtual flow meter, and the results from the virtual meter are compared to measurements made with an ultrasonic flow meter. Theoretical uncertainty analysis shows that the total uncertainty in flow rates from the virtual flow meter is 1.46% with 95% confidence; comparison of virtual flow meter results with measurements from an ultrasonic flow meter yielded an uncertainty of 1.46% with 99% confidence. The comparable results from the theoretical uncertainty analysis and empirical comparison with the ultrasonic flow meter corroborate each other and tend to validate the approach to computationally estimating uncertainty for virtual sensors introduced in this study. Furthermore, the results show that the total uncertainty in flow rates from this virtual flow meter is adequately low for use in place of common physical flow meters for monitoring thermal energy use in air handlers and detecting operational and equipment faults that affect energy consumption.

UR - http://www.scopus.com/inward/record.url?scp=84877677835&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84877677835&partnerID=8YFLogxK

U2 - 10.1080/10789669.2013.774890

DO - 10.1080/10789669.2013.774890

M3 - Article

AN - SCOPUS:84877677835

VL - 19

SP - 335

EP - 345

JO - Science and Technology for the Built Environment

JF - Science and Technology for the Built Environment

SN - 2374-4731

IS - 3

ER -