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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• 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

Presentation Outline:

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Lets look at a few examples………

Office Building A $94,658

Office Building B $47,905

Annual Energy Savings =

$46,753Nearly 50%!

Each building requires 470 tons of cooling; accomplished by way of:(2) air-cooled helical-rotary chillers piped in parallel(1) Pump per Chiller

How is this possible?

System Flow

Pumping Energy

Consumed Monthly

Annual Operating

Costs

Office Building A

Constant Primary,Constant

Secondary52,588 kWh $94,658

Office Building B

Variable Primary, Variable,

Secondary (VPF)26,614 kWh $47,905

*assuming $0.15 per kWh

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• How do you determine the efficienciesof 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)

• 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.

Main BuildingA

Annex BuildingB

Building / Campus Mapping:

• 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…

Annex BuildingC

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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 relativeto 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

• 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

Clamp-on, Fixed

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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

• 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

• 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 onthe 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 MetersEnergy 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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• 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

Summary:

Brent BairdPresident / Application Engineer / Technical Speaker

Instruments Directbbaird@instrumentsdirect.comwww.instrumentsdirect.com