Energy (BTU) Flow Survey with Clamp

Energy (BTU) Flow Survey with Clamp-On
Ultrasonic Flow Meters & Temperature.
Presented by: Brent Baird
AIA Quality Assurance
The Building Commissioning Association is a Registered Provider
with The American Institute of Architects Continuing Education
Systems (AIA/CES). Credit(s) earned on completion of this program
will be reported to AIA/CES for AIA members. Certificates of the
Completion for both AIA members and non-AIA members are
available upon request.
This program is registered with AIA/CES for continuing professional
education. As such, it does not include content that may be deemed
or construed to be an approval or endorsement by the AIA of any
material of construction or any method or manner of handling, using,
distributing, or dealing in any material or product.
Questions related to specific materials, methods, and services will
be addressed at the conclusion of this presentation.
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Learning Objectives
At the end of this session participants will be able to:
1. Articulate the basic theory of ultrasonic flow and RTD
technology.
2. Reflect on the applications, considerations, and pitfalls of the
energy survey.
3. Utilize best practices for clamp-on energy surveys.
4. Implement ways to keep your labor and equipment making
money.
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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
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Lets look at a few examples………
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Office
Building A
$94,658
Office
Building B
$47,905
Annual Energy Savings =
$46,753
Nearly 50%!
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
• 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
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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)
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Btu = The amount of heat energy it takes to raise the
temperature of one pound of water by one degree Fahrenheit,
at sea level.
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How it works:
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Key Issue(s):
-Too many application assumptions.
-Installations not per specifications.
-Poor or inaccurate data collection.
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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…
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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.
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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.
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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
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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.
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THE SOUND'S TIME OF FLIGHT IS
ACCURATELY MEASURED IN BOTH
DIRECTIONS AND THE DIFFERENCE IN TIME
OF FLIGHT CALCULATED.
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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
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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
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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
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Using Portable Ultrasonic Meters
1. Determine Transducer site
2. Pipe/Transducer Preparation
3. Install Transducer to Pipe
Clamp transducer to pipe at the
prepared area.
Adjust transducer knobs until sensors
are snug to pipe surface.
Attach cables according to
upstream/downstream.
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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
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Using Portable Ultrasonic Meters
1. Determine Transducer site
2. Pipe/Transducer Preparation
• Prep / Clean Pipe
• Remove insulation if any
• Apply Acoustic Couplant to the
sensors.
• Adjust Transducer Spacing
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Location.. Location… Location….
• Mount the RTD – temperature sensors in the identical location on
the supply and the return (metal) pipes.
• Failure to-do so will result in temperature differentials that can
effect your performance of the BTU calculations
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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
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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
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Brent Baird
President / Application Engineer / Technical Speaker
Instruments Direct
[email protected]
www.instrumentsdirect.com