Presented by Brent Baird Ultrasonic Flow Meters Optimize your Hydronic Energy Monitoring using...

Presented byBrent Baird

Ultrasonic Flow Meters

Optimize your Hydronic Energy Monitoring using

Non-ContactFlow & Temp

© Instruments Direct 2014


• Introduction• Why do you need energy metering?• Hydronic System Energy Metering applications• Noncontact Ultrasonic technology• Noncontact Temperature monitoring• Application of noncontact energy monitoring

applications• Economics

Presentation Outline:


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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 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 efficienciesof your current system?

•Use a reference meter to establish a baseline and map out your sources:

-Hot and Chilled water -Temperature (Differential) BTU

• Discover Process


What is Hydronic System Energy Metering?

A hydronic energy meter, also referred to as a BTU meter or heat meter. It 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.


• BTU/hr = flow rate in GPM (Δ Temp) 500

GPM*(abs(temp supply-temp return)*ROUND(((1-(((((temp supply+temp Return)/2)-32)/1.8)+288.9414)/(508929.2*(((((temp supply+temp Return)/2)-32)/1.8)+68.12963))*(((((temp supply+temp Return)/2)-32)/1.8)-3.9863)^2)*8.34540445),3)*1)=BTU/min

500 = the “fluid factor” this is based on water as the heat transfer fluid. The fluid factor is obtained by using the weight of a gallon of water (8.33 lbs.) multiplied by the specific heat of the water (1.0) multiplied by 60 (minutes). This comes out to 499.8 when using water.


How it works:


What have we learned so far:

-We need to monitor our energy system to optimize performance.

+ Flow – Supply+ Temperature – Supply

+ Temperature – Return


Main Building A

Annex Building B

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 Building C


Key Issue(s):

-Too many application assumptions are being made -Installations not per specifications-Accuracies of metering instruments-Poor or inaccurate data collection.


• 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.


Example: 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/HrUltrasonic = 7410 – 7560 MBtu/Hr, or +/- 1%Impeller = 7186 – 7784 MBtu/Hr, or +/- 4%


Example:

•For chilled water applications, temperature sensor accuracy relative toeach 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.


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


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


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.


Clamp-on Technology for Flow & TemperatureClamp-on Ultrasonic Transit Time Flow Meter

Clamp-on RTD Precision Temperature sensors


Clamp-on Technology : Doppler

The Doppler meter continuously transmits high frequency sound that travels through the pipe wall and into the flowing liquid.

Sound is reflected back to the sensor from solids or bubbles in the fluid. If the fluid is in motion, the echoes return at an altered frequency proportionate to flow velocity.

Doppler flow meters continuously measure this frequency shift to calculate flow.

B

A

Clamp-on Technology : Transit Time



THE SOUND'S TIME OF FLIGHT IS ACCURATELY MEASURED IN BOTH

DIRECTIONS AND THE DIFFERENCE IN TIME OF FLIGHT CALCULATED.

APPLICATIONS:


* Water Monitoring * Energy Management * HVAC * Test & Balance * Chillers * Cooling Towers * Boilers * And More……..


• 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

Clamp-on, Portable


• 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


Flow - Temperature Monitoring


Resistance temperature detectors or RTD’s as they are

more commonly known, are another common way to measure temperature.

To use an RTD, a small voltage is passed through the element

and then measured. The resistance of the element

reduces the voltage and this voltage drop can be converted

into a temperature measurement.

With most RTD’s, the higher the temperature, the higher the

resistance. 5(w) + 1000 + 5(r) = 1010 – (5(w) + 5 (r)) = 1000


5(w) + 1000 + 5(r) = 1010 – (5(w) + 5 (r)) = 1000

The 3-wire circuit does allow for compensation of lead wire

resistance, which is normally done by the measuring

instrument.

The instrument measures the resistance between the red and

the white leads and then subtracts the resistance between the two reds.


Temperature – Flow Monitoring


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


Using Portable Ultrasonic Meters

• Discover process.• Spot check flows• Water usage study• Energy usage study• Balancing Hydronic

system• Economics


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


Summary:

• 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• There are different ultrasonic technologies• Install submetering correctly for accurate continual data collection

and operations of your facility.• Define communications for your submetering

• Validate your ROI on any system upgrades.

Brent BairdCEO / Application Engr / Technical SpeakerInstruments DirectPh 1(888)[email protected]

QUESTIONS & ANSWERS


CRS-401(2”-26”)

CRS-402(28”-100”)

UTXDR-408(0.5”-2”)


Presented by Brent Baird Ultrasonic Flow Meters Optimize your Hydronic Energy Monitoring using...

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