Reducing Energy Costs with Efficient Facilities Energy Management

Are rising energy costs and process inefficiencies impacting your bottom line?

In today’s industrial environments, controlling energy costs while maximizing operational efficiency is essential for long-term success. Facilities that depend on natural gas, compressed air, steam, or water know that precise flow measurement is the key to optimizing processes and reducing unnecessary expenses.

Advanced flow meters empower organizations to accurately monitor and manage these critical resources, enabling smarter decisions, improved reliability, and substantial cost savings. In this article, we’ll explore how modern flow measurement technologies can help achieve peak efficiency across a wide range of applications and reduce operating costs regardless of your industry.

Smart Flow Energy Management Solutions

What fluid flows does your operation depend on? Whether they’re liquids, steam, or other gases, your ability to control costs depends on the accuracy and efficiency with which you can measure and manage flows.

Let’s examine these types of fluid flow and determine the best measurement technology solutions to apply.

1. Natural Gas and Compressed Air

Natural gas and compressed air are among the most common fluid flows measured in facilities. Many plants use natural gas for burner control in manufacturing or to fuel boilers which produce steam or hot water. Facilities may also require tracking of gas distribution for allocation and billing.

No matter the application, facilities managers need precise natural gas measurement to manage flow and control energy costs.

Similarly, compressed air requires energy-intensive compressors for production. Facility managers need accurate flow information to measure compressor efficiency, identify leaks in the system, and balance distribution of their compressed air.

The turbine flow meters and pitot tubes used in the past to measure gas flow have become antiquated. Turbine meters don’t work well for low flows of compressed air, and pitot tubes are prone to clogging. Furthermore, both of these technologies measure gas volume rather than mass flow and require complex calculations involving fluid temperature and pressure to measure mass.

The Mass Flow Advantage

Thermal mass flow meters are ideal for natural gas combustion and allocation because both applications require mass flow rate, not volumetric flow rate. The optimal air-to-fuel ratio for efficient combustion is calculated on a mass basis. Natural gas is also billed on a mass basis.

Measuring compressed air presents its own challenges. In many facilities, usage varies throughout the day, from very heavy at times of peak manufacturing to small flows (including leakage when processes are on standby.

Thermal flow meters have a very wide turndown rate (100:1) to handle such fluctuations. Plus, they have little to no pressure drop. Your facility is already paying to compress your air, so a needless pressure drop is wasted money.

In a thermal flow meter’s simplest working configuration, gas flows past a heated thermal sensor and a temperature sensor. Heat is transferred from the heated thermal sensor to the gas molecules as they flow past. This cools the thermal sensor, while the temperature sensor continues to measure the temperature of the fluid.

Figure 1. Thermal mass flow principle of operation

The amount of heat lost depends on the fluid’s thermal properties and its flow rate. By measuring the current required to heat the thermal sensor to a constant temperature differential from the temperature sensor, the flow rate can be calculated.

Because thermal mass flow meters effectively count the molecules of gas flowing past the sensor, they are immune to changes in inlet temperature and pressure.

Advances in four-sensor thermal technology, stable dry-sense sensors, and thermodynamic modeling now allow some thermal flow meters to achieve accuracy as precise as ±0.5% of reading, which is comparable to the accuracy of a Coriolis meters but at a lower cost. Built-in software also supports gas mixing, in-situ validation, and dial-a-pipe features.

Figure 2. QuadraTherm^® insertion thermal flow meter with four-sensor thermal technology

Advantages of Sierra Instruments' thermal mass flow meters for gases include:

Direct mass flow measurement eliminates the need for tertiary equipment to perform temperature and pressure compensation
Accuracy up to +/- 0.5% reading, low flows down to 15 sfpm, high flows up to 60,000 sfpm, and up to 1000:1 turndown
Multivariable mass flow rate, temperature, and pressure
Advanced four-sensor “dry sense” technology minimizes drift
On-board diagnostics for meter verification
Digital sensors and signal processing to enable gas correlations in the field—no need for factory recalibration when your gas composition changes
Hot-tap capabilities for easy insertion without process shutdown
Software applications for easy setup, calibration gas selection, and piping feature adjustments
Digital communications suite

Case Study 1: Compressed Air Audit Saves Thousands

Air may be free, but compressed air certainly isn’t. According to Cary Carlisle, an expert compressed air auditor from Air Compressor Supply, Inc. (ACS), over a 10-year period, electricity accounts for 76% of a factory’s operating costs. In many cases, the electricity used by a compressed air system in a factory makes up a major part of the electricity bill.

To evaluate plant efficiency, Carlisle begins with a compressed air audit. In most facilities, air usage fluctuates throughout the day, rising during peak production and dropping to minimal levels (often due to leaks) during standby periods. With accurate compressed air usage data, companies can assign real costs to compressed air and make informed decisions that drive savings.

In the past, processes operators would use volumetric or non-compensated flowmeters, which would present challenges in compressed air measurement. For example, even a small change in operating temperature could result in a 5-10% reduction in accuracy for outdated measurement technologies.

Carlisle switched to thermal mass flow meters for compressed air audits to gain direct mass flow measurement that remains accurate despite changes in operating temperature. With a 100:1 turndown ratio and improved accuracy, customers have seen annual savings of $7,500 to $44,000 by better managing their systems or upgrading to more efficient compressors—a significant return with a short payback period. Advanced software also enables Carlisle to provide verifiable proof that the meter’s accuracy hasn’t drifted over time.

2. Steam Flow Measurement

Figure 3. Multivariable insertion vortex flow meters are ideal for saturated and supersaturated steam measurement.

Steam plays a vital role across industries—from chemical processing and refineries to geothermal and nuclear energy production. Steam is used to optimize boiler efficiency, heat buildings and water, and support food processing. In nuclear power plants, steam generated by nuclear fission drives energy production.

Steam flow can be measured using a differential pressure device like an orifice plate, but these instruments are inherently volumetric flow measurements. Changes in pressure and temperature will change the mass flow rate of steam. Even a “small” change of 10% in steam pressure will result in a 10% error in non-compensated mass flow.

The volumetric flow rate measured by a differential pressure meter can only be compensated by also measuring temperature and pressure, and all three measurements must be tied into a flow computer to calculate mass flow. Thankfully, there are other steam measurement technologies that offer easier integration and lower cost of ownership.

Multivariable Vortex Flow Meters Increase Accuracy

Multivariable vortex flow meters allow one instrument and one process connection to simultaneously measure mass flow rate, temperature, pressure, volumetric flow rate, and fluid density. Combining all these process variables into a single device enables on-board pressure and temperature compensation, resulting in steam flow measurement uncertainty of +/-1% of reading or better, accurate density calculations, and a 30:1 turndown ratio.

Figure 4. Vortex sensor cutaway showing the vortex principle of operation

In addition to steam measurements, vortex shedding technology is a reliable, well-established method for measuring other gases and liquids. As fluid passes an obstruction, it creates vortices—like water around a rock in a stream or wind past a flagpole. In a vortex meter, a sensor near the obstruction oscillates with each vortex, generating a frequency output proportional to the flow rate (Figure 4).

Multivariable mass flow is achieved when a temperature sensor is immersed in the flow stream to measure the temperature of the fluid, while a pressure sensing port leads to a pressure transducer.

Key advantages of using Sierra Instruments’ multivariable vortex flow meters for steam measurement include:

Lower cost-of-ownership, with one meter with one process connection measuring up to five process variables—volumetric flow rate, mass flow, density, pressure and temperature
Dynamic density calculations improve steam metering accuracy—up to +/- 0.7% of reading
More rangeability than differential pressure devices—30:1 turndown ratio
Hot-tap insertion probes with retractors for easy installation without stopping your process
Onboard software facilitate setup, application tuning, and validation for ease of use.

Case Study 2: Crab Plant Boosts Efficiency & Quality

A large seafood processing plant needed better steam management to flash-cook thousands of pounds of freshly caught crab daily. The plant’s process uses clean steam, produced from purified water in a dedicated generator, which comes in direct contact with the crab to ensure food safety and ideal texture.

Accurately measuring steam temperature, pressure, and flow is essential for both product quality and operational efficiency. The plant previously used volumetric orifice plates, which presented three problems:

Inaccurate mass flow measurements due to separate pressure and temperature sensing points, impacting both efficiency and product quality.
Higher installation costs from the need to buy separate sensors and make multiple penetrations in the pipe for multiple instruments.
Frequent maintenance caused by clogging and wear, especially problematic in the plant’s 24/7 operations.

Switching to an insertion multivariable vortex flow meter delivered major improvements:

Improved accuracy and streamlined measurement of all the key process variables with a single instrument.
Reduced downtime and installation cost using a hot-tapped insertion probe with a retractor assembly.
Smart software features for auto-adjusting the meter, verifying proper function, and printing in-situ validation certificates to meet food industry regulations.

3. Water & BTU Measurement

Facilities commonly measure water flow for billing, leak detection, and monitoring of influents and effluents. Thermal energy measurement is also gaining importance as facilities invest in HVAC and other processes using hot and chilled water. To manage that distribution and allocation of water, accurate BTU measurement is essential.

Several technologies are used to measure water flow, many with limitations:

Vortex meters perform well but lose accuracy at low flow rates.
Turbine and propeller meters are common but have moving parts that are prone to wear and clogging.
Magnetic flow meters are widely used but can’t measure deionized water, which is common in certain industries.

Clamp-On Ultrasonic Liquid Flow Meters Offer Ease of Use & Flexibility

Clamp-on ultrasonic flow meters are ideal for water flow applications. They achieve high accuracy at low and high flows, are non-invasive, require no process shutdown for installation, and are virtually unaffected by external noise. Coupled with temperature sensors on the “hot” and “cold” legs, the thermal energy gained or lost can be measured (Figure 5). This technique is commonly applied in distributed and district energy, where central heating and cooling plants provide HVAC to the entire facility.

Figure 5. Clamp-on ultrasonic liquid flow meter with thermal energy/BTU capability

With a transit-time ultrasonic liquid flow meter, the upstream transducer transmits an ultrasonic signal in the direction of flow, and another signal is transmitted back against the flow by the downstream transducer (Figure 6). The time for the sonic pulse to travel downstream is compared to the time for the pulse to travel upstream, and that time differential is used to calculate the velocity of the flowing fluid.

Figure 6. Transit-time ultrasonic principle of operation

Ultrasonic flow meters use the fluid velocity to calculate the volumetric flow rate in the pipe. Energy measurement (in BTU or similar units) can be derived from the volumetric flow rate and the temperature difference between the hot and cold legs. New developments in ultrasonic technology coupled with modern software applications now allow for real-time liquid density compensation as well.

Advantages of Sierra Instruments' ultrasonic flow meters for flow and BTU measurements of water include:

Clamp-on transducers are non-intrusive and measure bi-directional flow
One meter design to cover a wide range of pipe sizes—from 1/2 inch to 200 inches (15 mm to 5000mm)
Accuracy up to +/- 0.75% of reading
Suitable for process temperatures up to 248°F (120°C)
Software apps to optimize ultrasonic signal strength
Energy Monitoring—calculate energy usage in BTU and similar units of measurement

Case Study 3: Water Company Improves Water Loss Measurement

Carmel Riviera Mutual Water Company, a small rural utility serving 600 homes along California’s Big Sur coast, faced challenges in accurately measuring water loss—a key concern for system operators.

Historically, the company estimated that 30% of its produced water was lost to leaks, waste, and evaporation. To address this, it budgeted nearly $60,000 annually for leak detection and repair efforts. As part of the initiative, Carmel Riviera implemented clamp-on ultrasonic flow measurement technology.

After six months, the new meters revealed the actual water loss was just 12%—an 18% improvement over prior estimates. With more accurate data, the company was able to reduce unnecessary spending and reallocate its maintenance budget toward long-term conservation and efficiency improvements.

Sierra Instruments Wide Range of Solutions for Complex Flow Challenges

Sierra is a global leader in flow measurement and control solutions. We design and manufacture precision devices that can be trusted to deliver a high degree accuracy, reliability, and efficiency.

Our expertise spans multiple technologies and industries:

Thermal Mass Flow: Sierra is a pioneer in thermal mass flow technology for gas measurement that provides unmatched accuracy.

Advanced Vortex Solutions: We supply industry-leading multivariable vortex flow meters with retractable brackets for easy installation—no shutdown required.

Portable Ultrasonic Meters: Our compact, field-ready ultrasonic meters with clamp-on transducers promise fast, reliable measurements in the field.

Whether you need to measure natural gas, compressed air, steam, water, or energy (BTU) flows, Sierra provides proven, cost-effective solutions tailored to your needs.

Discover our complete range of flow measurement solutions—contact us today.

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