Ultrasonic Flow Meters
Energy
Monitoring with
Ultrasonic Flow
Meters
Presented by
Brent Baird
Ultrasonic Flow Meters
Presentation Outline:
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Introduction
Why do you need energy monitoring metering?
What is Hydronic System Energy Metering?
Why use Submetering?
Types of Flow / Energy Meter Technologies
Typical applications
Economics
Ultrasonic Flow Meters
Ultrasonic Flow Meters
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Ultrasonic Flow Meters
Lets look at a few examples………
Ultrasonic Flow Meters
Office Building A
$94,658
Office Building B
$47,905
Annual Energy Savings =
$46,753
Nearly 50%!
Ultrasonic Flow Meters
How is this possible?
Each building requires 470 tons of cooling; accomplished by way of:
(2) air-cooled helical-rotary chillers piped in parallel
(1) Pump per Chiller
System Flow
Pumping
Energy
Consumed
Monthly
Annual
Operating
Costs
Office Building
A
Constant Primary,
Constant Secondary
52,588 kWh
$94,658
Office Building
B
Variable Primary,
Variable, Secondary
(VPF)
26,614 kWh
$47,905
*assuming $0.15 per kWh
Ultrasonic Flow Meters
• How do you determine the efficiencies
of your current system?
• Discover Process
• Use a reference meter to establish
a baseline and map out your sources:
-Hot and Chilled water
-Temperature (Differential) BTU
Ultrasonic Flow Meters
What is Hydronic System Energy Metering?
A hydronic energy meter, also referred to as a BTU meter or heat
meter, measures heat energy generated by a source or transferred
to a load depending on heating or cooling demands.
Energy Measurement unit is called Btu (British thermal unit)
• Btu = The amount of heat energy it takes to raise the
temperature of one pound of water by one degree Fahrenheit,
at sea level.
Ultrasonic Flow Meters
How it works:
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Key Issue(s):
-Too many application assumptions.
-Installations not per specifications.
-Poor or inaccurate data collection.
Ultrasonic Flow Meters
Building / Campus Mapping:
Main Building
A
Annex Building
B
Annex Building
C
• In calculating energy use, each building
is unique.
• Address temperature loss or gain when
transferring CHWS, CHWR.
• Meter all flows and temperatures, you
cant afford not too…
Ultrasonic Flow Meters
• For chilled water applications, where the sensor supplies only
volume information to a Building Automation System (BAS), each
percentage error the flow meter is off will have a direct impact on
the Btu calculation.
• Flow meter technologies come with wide accuracy statements.
• For instance, if one flow sensor is advertised with accuracies of
1% of Reading while another is 1% Full Scale, the energy
calculation can be off by 4% when flows are run at 25% of full
range.
Ultrasonic Flow Meters
On an 8” Chilled Water line; a 1% of Reading Ultrasonic and a 1% FS
Impeller are installed. Both have max working flow rates of 0-4000
GPM with an application design flow of 1000 GPM.
The ultrasonic meter will offer readings of 990-1010 GPM in order to
meet its advertised +/-1% of readings.
The impeller meter will offer readings of 960-1040 GPM in order to
satisfy its +/-1% of Full Scale readings.
Assuming a delta-T of 15ºF, the designed flow of 1000 GPM, and a
water constant of 499: Q(Btu/hr) = (GPM)(499)(delta-T)
True Energy Value = 7485 MBtu/Hr
Ultrasonic = 7410 – 7560 MBtu/Hr, or +/- 1%
Impeller = 7186 – 7784 MBtu/Hr, or +/- 4%
Ultrasonic Flow Meters
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For chilled water applications, temperature sensor accuracy relative to
each other becomes significant since the temperature differences can
be small (<10° F).
For instance, if one sensor reads 1° F high while the other is 1° F low,
the energy calculation can be off by 20%.
A self-contained “Btu” meter is recommended as opposed to using
separate flow and temperature sensors because the accuracy is
generally better (matched sensors) and data collection is simpler,
particularly if energy is being metered for revenue purposes.
Ultrasonic Flow Meters
When selecting technology, you should consider:
Pipe considerations – Include pipe size and material, layout, and straight pipe runs available for
flow sensor installation.
Flow rate –Flow sensors must be sized to accommodate any balancing configuration or valve
position.
System temperature – Flow and temperature sensors are designed especially for chilled or hot
water systems. Example: thermistors are fine for chilled water, but RTD’s are a better selection
for hot water systems.
Accuracy – Accuracy and repeatability help determine how precise your energy measurements
will be. Some applications leverage tighter accuracy and repeatability tolerances to maintain
tighter controls on hydronic system performance.
Service considerations – For new installations, direct insertion of sensors is usually possible.
However, when retro-fitting a system, often pipes cannot be drained requiring a wet tap.
Optional display – Depending on owner requirements, local displays of flow, temperature,
energy rate, and/or energy totals may be required.
Optional connectivity – Data logging and Building Automation System (BAS) networks, in
addition to simple pulse and analog signals, include many different network protocols
Ultrasonic Flow Meters
Energy Management is Key
• Optimizing usage/minimizing operating costs
– Energy distribution
• Measuring consumption
– System monitoring
• Cost allocation
– Energy sub-metering
• Measurement and Verification is an essential part
of every energy efficiency facility program
• Federal and state agencies encourage investment
in energy-saving technology
Ultrasonic Flow Meters
Submetering - involves the installation of equipment to measure,
monitor, bill or control your process of your water, sewer, gas and
electric use. Because submetering raises facility operation
awareness, users work harder to conserve, thereby reducing overall
consumption dramatically.
Discovery-(Portable) Metering – Insertion meters can be very time
consuming and expensive. Clamp-on survey meters are more
practical. Ideal for spot check or extended study. Justification to add
submetering or retrofit your system.
Ultrasonic Flow Meters
Ultrasonic Flow Meters
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THE SOUND'S TIME OF FLIGHT IS
ACCURATELY MEASURED IN BOTH
DIRECTIONS AND THE DIFFERENCE IN TIME
OF FLIGHT CALCULATED.
Ultrasonic Flow Meters
• Select your meter technology
• Invasive or Non-invasive
Ultrasonic Flow Meters
Impeller Meter
• Basic principles
– Mechanical Impeller spins with flow
• Key advantages
– Easy to install
– Hot tap installation
– Economical Price
• Applications
– Clean cold or hot fluids, pipes must
be full
– Installation cost and service can be
very costly
Ultrasonic Flow Meters
Magnetic Meter
• Basic principles
– Uses an electromagnetic field
• Key advantages
– No moving parts
– No pressure drop
– Accurate with reduced pipe runs
• Applications
– Water and other conductive fluids
– Installation cost and relatively
maintenance cost.
Ultrasonic Flow Meters
Clamp-on, Fixed
• Basic principles
– Uses ultrasound waves
to measure flow
• Key advantages
– Non-invasive
– No need to shut
down system
– Economical Price
• Applications
– Relatively clean cold or hot fluids,
pipes must be full
– No maintenance costs
Ultrasonic Flow Meters
Clamp-on, Portable
• Basic principles
– Uses ultrasound waves
to measure flow
• Key advantages
– Non-invasive
– No need to shut
down system
– Rental & Purchase
• Applications
– Relatively clean cold or hot fluids,
pipes must be full
– No maintenance costs
Ultrasonic Flow Meters
APPLICATIONS:
* Water Monitoring
* Energy Management
* HVAC
* Test & Balance
* Chillers
* Cooling Towers
* Boilers
* And More……..
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Using Portable Ultrasonic Meters
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Discover process.
Spot check flows
Water usage study
Energy usage study
Balancing Hydronic
system
• Economics
Ultrasonic Flow Meters
Using Dedicated Ultrasonic Meters
Energy monitoring & control
by monitoring BTU
• Flow and temperature
• Domestic hot & cold water
• Air conditioning / Heater
• Communications
- 4/20mA
- Modbus
- Ethernet
- BACnet MSTP
- BACnet/IP
- Modbus TCP/IP…..
• Economics
Ultrasonic Flow Meters
Ultrasonic Flow Meters
Summary:
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We all live in a bubble and need to control our environment
Energy monitoring can enhance your facilities efficiencies
A discovery process is necessary to establish a baseline
Install submetering correctly for accurate continual data collection
and operations of your facility.
• Define communications for your submetering
• Submeter / Flow Meter Budget economics
QUESTIONS & ANSWERS
Brent Baird
CEO / Application Engr / Technical Speaker
Instruments Direct
Ph 1(888)722-5543
bbaird@instrumentsdirect.com
CRS-401
(2”-26”)
CRS-402
(28”-100”)
UTXDR-408
(0.5”-2”)