| dc.creator |
Bryant, J. A. |
en_US |
| dc.creator |
O'Neal, D. L. |
en_US |
| dc.date.accessioned |
2008-05-16T16:17:47Z |
|
| dc.date.available |
2008-05-16T16:17:47Z |
|
| dc.date.issued |
1996 |
en_US |
| dc.identifier.other |
ESL-HH-96-05-07 |
en_US |
| dc.identifier.uri |
http://handle.tamu.edu/1969.1/6668 |
|
| dc.description.abstract |
Thermal energy consumption in buildings with
chilled or hot water distribution systems is often
monitored through the use of some type of flow
metering device. These flowmeters can be fixed types,
such as venturis or orifices, or insertion flowmeters
which can be more easily installed and removed. The
easy removal and reinstallation of the insertion type
flowmeters makes them good choices for use in
existing buildings or in retrofit projects. Besides the
installation benefits, insertion flowmeters can also be
installed while the pipe is in service or ''hot tapped".
With any type flowmeter however, location in the pipe
is a critical problem and deserves special
consideration. Ideally, the meter should be inserted in
existing pipe with a minimum of 10 to 15 diameters of
straight pipe upstream of the meter location. This is
rarely the case in existing piping distribution systems.
It is much more common to be faced with only one or
two candidate metering locations and these often are
very short straight runs or will have elbows upstream
and downstream of the proposed metering location.
This paper reports on flow measurement error
resulting from an insertion flowmeter installed
downstream of a 90° elbow. The measurement errors
were compared for tests conducted in 4.0 and 6.0 inch
(0.1 and 0.15 meter) diameter PVC pipe. The
insertion flowmeter was a nonmagnetic, tangential
paddle wheel type. The flowmeter was located from 2
to 10 pipe diameters downstream fiom a 90° elbow
with fluid velocities ranging from 1.0 to 10.0 ft/s (0.3
to 3.0 m/s). At each flowmeter location, the meter was
rotated in 45° increments around the circumference of
the pipe to quantify the effect of circumferential
location on flow error.
The flowmeters were tested at the energy metering
calibration facility at the Texas A&M University
Energy Systems Laboratory Riverside campus.
Flowmeter output was compared to mass flow
measurements obtained 6om precision load cells
mounted beneath a 1342 ft^3 (38 m^3 ) weigh tank. All
output is given in terms of percent error relative to the
load cells. Final results are presented as a bction of
flowmeter downstream location, circumferential
rotation angle, and fluid velocity. Circumferential
meter location was found to be a very important factor.
The percent difference for the tested flow meters
ranged 6om -23% to -5% in the 4.0 in. (0.1 m) pipe
and 6om -33% to 1% in the 6.0 in. (0.15 m) pipe. The
''best" location for these flowmeters was at zero
degrees rotation angle, regardless of pipe size or meter
location relative to the upstream 90° elbow. |
en_US |
| dc.description.provenance |
Made available in DSpace on 2008-05-16T16:17:47Z (GMT). No. of bitstreams: 1
ESL-HH-96-05-07.pdf: 383903 bytes, checksum: 1439dc38abaed264215e59794082609a (MD5)
Previous issue date: 1996 |
en |
| dc.publisher |
Energy Systems Laboratory (http://esl.tamu.edu) |
en_US |
| dc.publisher |
Texas A&M University (http://www.tamu.edu) |
en_US |
| dc.title |
Effect of a 90° Elbow on the Accuracy of an Insertion Flowmeter, Results and Comparisons for 4 and 6 in. Diameter PVC Pipe |
en_US |
| dc.contributor.sponsor |
The University of Texas at El Paso |
en_US |
| dc.contributor.sponsor |
Texas A&M University |
en_US |
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