Showing posts with label Campus Metering. Show all posts
Showing posts with label Campus Metering. Show all posts

Saturday, November 11, 2017

Clamp-on, Transit-time Difference Ultrasonic Flowmeters Ideal for HVAC Retrofit and New Construction

Transit-time Difference Ultrasonic Flowmeters
Transit-time Difference Ultrasonic Flowmeters (Flexim)
There are many reasons for large commercial buildings, medical centers, museums, airports, sports complexes, federal institutions and military complexes to invest in building energy optimization efforts. Better and more efficient operation of HVAC equipment can reduce the buildings energy and operational costs significantly.

Controlling flow, temperature and pumps can provide energy cost savings of over 20%. Many campus energy managers believe that the biggest user of energy in any complex is the HVAC system, and the key to saving energy in HVAC systems is an accurate and reliable flow metering capability.

Better efficiency of the heating and cooling infrastructure of a building also leads to more environmentally friendly buildings, something that has become a social prerogative of building owners and operators.  Older buildings were not built with BTU meters as metering requirements were added to buildings through increased regulations.

Submetering the buildings heating and cooling systems have become increasingly more important, as building owners are both mandated to meter these utilities and have a financial interest in the accuracy of these BTU measurements. The problem historically is that nearly all flow meters are designed for gradual failure due to direct contact with the fluids they are monitoring and the particulate accumulation on the sensors.

Clamp-on, transit-time difference ultrasonic flowmeters are the ideal retro-fit flowmeter, and also should receive strong consideration for new building construction. Transit-time difference ultrasonic clamp on flowmeters exploit the fact that the transmission speed of an ultrasonic signal depends on the flow velocity of the carrier medium - kind of like a swimmer swimming against the current. The signal moves slower against the flow than with it.

How Transit-time Difference Ultrasonic Flowmeters Work

The flowmeter sends ultrasonic pulses through the process medium - one in the same direction as the
flow and one in the opposite direction. The flowmeter's transducers alternate as emitters and receivers. The transit time of the signal going with the flow is shorter than the one going against. The flowmeter measures transit-time difference and determines the average flow velocity of the process medium. Since ultrasonic signals propagate in solids, the flowmeter can be conveniently mounted directly on the pipe and measure flow non-invasively.

Contact Flow-Tech with your questions about any flow measurement application. Reach them at 410-666-3200, or visit

Saturday, September 30, 2017

Campus Metering: Why Meter?

Instrumentation Energy Management
Schools, universities, medical centers and federal building
use instrumentation for energy management.

Energy and water managers have long known the value of metered data. With recent advances in energy and water metering and information systems resulting in increased functionality at lower costs, obtaining these data in a cost-effective manner is now a standard practice. Whether energy and water resource managers are trying to comply with legislated and mandated metering requirements, or looking to apply accepted building management best practices, such as utility bill verification or benchmarking, today’s metering technologies can provide the information needed to meet energy and water goals, save money, and improve building operations.

Metering of energy and water utilities has seen an increase in interest, application, and technology
Clamp-on flow meter
Clamp-on flow meter (Flexim)
advancement in both the private and the public sectors. One significant driver of this heightened interest is the ongoing modernization of the nation’s electric infrastructure with the move toward the smart grid and smart meters. Another significant driver, specific to the Federal sector, includes the legislative mandates for metering of Federal buildings.

The Business Case for Metering

The application of meters to individual buildings and energy-intensive equipment provides facility managers and operators with real-time information on how much energy has been or is being used. This type of information can be used to assist in optimizing building and equipment operations, in utility procurements, and in building energy budget planning and tracking.

It is important to keep in mind that meters are not an energy efficiency/energy conservation technology per se; instead, meters and their supporting systems are resources that provide building owners and operators with data that can be used to: 
Flow computer
Flow computer (KEP)
  • Reduce energy and water use
  • Reduce energy and water costs
  • Improve overall building operations 
  • Improve equipment operations
How the metered data are used is critical to a successful metering program.

Depending on the type of data collected, these data can enable the following practices and functions:
  • Verification of utility bills
  • Comparison of utility rates
  • Proper allocation of costs or billing of reimbursable tenants 
  • Demand response or load shedding when purchasing electricity under time-based rates 
  • Measurement and verification of energy project performance 
  • Benchmarking building energy use 
  • Identifying operational efficiency improvement opportunities and retrofit project opportunities 
  • Usage reporting and tracking in support of establishing and monitoring utility budgets and costs, and in developing annual energy reports. 
Most of the metered data uses listed above will result in a reduction in energy and water costs. The degree of cost reduction realized will depend on the unit cost of the energy and water being saved and on the effectiveness with which the site analyzes the data and acts upon its findings and recommendations. Examples of additional metering benefits can include:
Inline flowmeter
Thermal dispersion flow meter (FCI)
  • Supporting efforts to attain ENERGY STAR and/or green building certifications 
  • Promoting tenant satisfaction by providing information that tenants find useful in managing their operations 
  • Prolonging equipment life (and reducing capital investment requirements) and improving its reliability by verifying the efficient operation of equipment 
  • Assessing the impact of utility price fluctuations prior to or as they happen, allowing sites/agencies to address budget shortfalls on a proactive basis. 
Metering options will change in response to new material, electronic, and sensor development, as well as new and additional requirements for real-time data information. Future expansion of a metering system should be considered, as well as introduction of new metering and sensor technologies, based on the best available information, but be careful not to over design a system, thus unnecessarily increasing its cost.

Contact Flow-Tech with questions about improving your facilities energy management systems.  

Wednesday, May 31, 2017

Heated or Chilled Water Concepts in Campus Metering Applications

Reprinted with permission from KEP

Typical Heated/Chilled Water Metering System Using Magnetic Flowmeter System, Two Temperature Transmitters and Electronic Flow Computer.

A typical modern, heated/chilled water metering system usually consists of several components:
  • Flow Meter installed in the line
  • A temperature transmitter mounted in the supply line to measure the supply temperature 
  • A temperature transmitter to measure return temperature 
  • A Flow Computer that will compute the energy flow 
  • An optional Data Logger/Modem that will monitor the customer site and provide trend information 
If remote metering is required, a remote PC, modem, and remote metering software may be used in conjunction with this.
Typical Heated/Chilled Water Metering System
Typical Heated/Chilled Water
Metering System with Flow Computer

Equipment Selection

The flowmeter is sized by the manufacturer based on the expected line size, fluid and flow rates anticipated in the application. This would normally require the line size, flow rate range and expected line conditions of temperature and pressure be known. The temperature transmitters are selected for a measurement range that will meet or exceed the range of temperature to be encountered in the application. The flow computer performs the necessary calculations needed to compute the energy flow (BTU’s or ton-hours) from the electrical signals being fed into it. The optional data logger and modem permit the remote monitoring of those signals and the data logging of the measured and computed values. A remote PC with modem can access the information either in the data logger or in the current readings of the flow computer.

Factory Calibration

The flow meter, flowmeter, the transmitters and the flow computer are calibrated by their respective manufacturer’s prior to being supplied to a utility company in accordance with the instructions provided when the units are purchased.


During installation the two temperature transmitters and the flow computer are installed in accordance with industry guidelines and manufacturers instructions.

The individual calibration and setup documents provided by the manufacturers are reviewed.


During startup the individual components of the systems are setup so that they operate correctly.

For the transmitters this will normally involve double-checking of each transmitter range and optional features using a hand held terminal.

The flow computer will be setup by entering the information on the flowmeter, and with the ranges of both temperature transmitters. In addition, the desired items to be included in the data logger will also be setup. This is usually done by the front keypad although connecting the device to a laptop and using an external, special program supplied by the manufacturer could also be used.

The setup of each individual input item is verified. For each measurement, there is a transmitter to scale and send an electrical signal to the receivers that need this information. The scaling of each transmitter must also be set into the corresponding flow computer input channel. If a change is made to one, it must be made to all.

The basic operation of the system can be verified by checking that the respective sensors are producing the correct signals, based on the observed signal, the flow range setup in the sender and receiver of the informa- tion, and the observed process conditions in the line. Signal simulators and multi meters may also be used.

When using voltage or current ranges for the flow input, there is a “low flow cutoff” that should be set to prevent the system from metering when no flow is present. This is also limits the low flow measurement range so it is usually set to the lowest practical value.

There is also a low temperature cutoff that can be used to prevent the false totalization of energy when small differential temperatures are indicated while recirculating water.

Meter Readings

Meters may be read either locally by taking a reading off the flow computer or remotely by taking a reading off the flow computer by modem or by reading the data logger or both. The operational status of the meter system is also checked periodically.

Servicing the Metering System

Often a utility will perform various inspections each year on each energy meter. Manufacturers of the compo- nents used in the system provide a number of service and test aids for Service personnel that permit them to interrogate a component to determine if it is operating properly. From time to time problems may occur in any system. The transmitters, flow computer, and data logger usually have some diagnostic capability and can assist in problem detection and notification.

If it becomes necessary, for any reason, the flowmeter may be changed out. This sometimes occurs when the heating load changes or the actual flow range is different than the expected range as a result of inaccu- rate sizing information. When a sensor change out occurs the information on the new flowmeter must also be set into corresponding transmitter and the flow computer flow input channel. If a change is made to one, the change must be made to all.

If a transmitter is changed by either replacement or re-scaling or re-spanning then the new scaling of that transmitter must also be set into corresponding flow computer input channel. If a change is made to one, the change must be made to all.

Most utilities remove portions of the meter system from service after several years for recalibration. The flow computer can usually be checked in place using simulators. They can be removed from service if needed and replaced with another device that then must be setup for use as described earlier. In other cases, the transmitters are replaced with a calibrated replacement unit.

KEP Flow Computer
Kessler-Ellis Products (KEP) offers the Supertrol 2 Flow Computer for Heated or Chilled Water Metering applications. It is available in a variety of housings to suite a wide range of application environments.

For more information on KEP products follow this Flow-Tech link or call 410-666-3200 in Maryland, or 804-752-3450 in Virginia.

Sunday, March 27, 2016

Campus Metering: Improve the Energy Efficiency of Your Building with Clamp-on Flowmeters

Clamp-on, Ultrasonic Flowmeter
Clamp-on, Ultrasonic Flowmeter
(courtesy of FLEXIM)
Today there are many reasons to focus on energy optimization efforts. Due to rising cost of fossil fuels and environmental concerns, decreasing overall energy consumption, decreasing operational costs, improving HVAC performance, improving building quality and certification rating is becoming increasingly important. Facility Managers are stepping up their efforts to find efficiency and savings related to heating, ventilation and air conditioning systems, including chillers, boilers, and air-handling components. Energy-efficiency is a top priority for institutional and commercial organizations and will continue to grow in importance for the foreseeable future.

Finding new ways to reduce energy consumption in buildings without compromising comfort and indoor air quality is an ongoing challenge. One of the most significant options a facility has is to add BTU energy metering that is able to accurately meter the new performance of upgraded chillers, pumps, and chilled water distribution system.

Superior precision can be achieved by using clamp-on flowmeters with specially matched and paired ultrasonic transducers and temperature probes that control the heating and cooling flows within the building. These devices offer a superior solution with a high degree of reliability and repeatability for both temporary and permanent applications.

The biggest challenge in retro-fitting flowmeters in existing piping structures are the very tight piping typical of chiller plants, existing valves, vents, and pipe bends. Clamp-on ultrasonic flowmeters provide an easy work-around. Since the clamp-on ultrasonic transducers are simply mounted on the outside of the pipeline, plant operation is not affected in any way during retrofitting. The reworking of existing piping systems for flowmeter installation is not required, making the clamp-on flow meters an ideal solution for retrofitting existing facilities.

Designed with temperature compensation to eliminate inaccuracies or drift through deviations, and powerful correction algorithms to compensate for non-ideal pipe conditions, these energy flow meters offer an accuracy of 1% or better on the flow rate. Plus, low flow velocities can be detected reliably and accurately.

The advantages for choosing clamp-on ultrasonic flowmeters for HVAC retrofit are:

  • Reliable, non-invasive recording of thermal energy (BTU) flows
  • Practically wear-free measurement without measurement drift, unaffected by potential coating formations
  • Works independently of the conductivity of the medium
  • Simple set-up of measuring points without any interruption of operation
  • Minimum installation effort
  • Compact measurement system, can also be easily installed on measuring points which are difficult to access

Research demonstrates the addition and/or upgrade of metering existing HVAC systems can offer effective solutions for energy conservation and thermal comfort, with possible energy savings in the range of 30-40%.

For more information on BTU/Campus/Building Metering, contact:

Flow-Tech, Inc.
10940 Beaver Dam Rd
Hunt Valley, MD 21030
Ph: 410-666-3200

Central VA Office
10993 Richardson Rd#13
Ashland, VA 23005
Ph: 804-752-3450