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Glocon discusses how it believes heating, ventilation and air-conditioning (HVAC) and process heat-transfer systems can achieve significant gains in energy efficiency.

According to the company, achieving significant gains in energy efficiency for HVAC and process heat-transfer systems that utilise high-volume air movement systems such as cooling towers, chillers and evaporative coolers has long eluded the industry.

In the past, much attention has been given to improving fan and blade airfoil designs used in such systems to help improve efficiency; however, only marginal gains have been made.

In addition, most fans have a limited operating range in which they can provide the optimum performance.

Glocon, which manufactures the Swifter series of high-performance industrial axial fans, believes that the solution to realising efficiency gains of 25 per cent or more requires an out-of-the-box approach.

In addition to using the latest fan and airfoil designs, system variables such as power, fan speed and blade pitch angle must be adjusted and managed constantly in real time during operation against the backdrop of the changing operating conditions of the system.

In essence, a smart air movement system (SAMS) using a modern versatile control solution is the key to the next generation of energy-efficient large-volume air movement systems.

Beyond managing system efficiency, a SAMS can monitor the health of a system and indicate potential problems or failures before they occur.

The foundation of a SAMS is integrated control.

Between five and seven years ago, the availability of integrated controls was scarce.

In addition, high costs offset most of the savings that could be garnered.

Since then, the electronics industry has evolved and, as a result, affordable components are now available to replace the inefficient electromechanical control systems of the past.

Industrial controls have followed a similar path as cellular telephones.

To match today’s smart mobile phone technology, an attache case would be needed to carry all the individual devices of the prevailing technology five years ago.

In addition, the data on a personal digital assistant (PDA) would have to be manually re-entered on a mobile phone.

Worse yet, if a telephone number changed, the end user had to check and double check all the individual places the number was stored.

Industrial controls suffered from the same scenario.

A cooling tower diverter had its own control.

Fan operation also relied on a separate temperature reference.

There was no single point of control based on the process variables that actually determined how the equipment should operate.

Affordability and reliability underscore the success of embedded controls today.

The term ’embedded’ implies that something is designed for a specific use.

The control is specially designed and programmed to manage the equipment with respect to the operating environment, desired results and energy savings.

A lifetime of system experience with the respective operating environment is encoded within the firmware (a program) that is embedded onto a specific-use computer.

In a heat exchanger system with a large air movement system, the pitch of a fan blade can be adjusted to operate in concert with its motor’s AC drive.

Energy savings can be optimised with respect to environmental conditions and in real time without operator intervention.

As an example, evaporative coolers are relied upon to deliver consistent heat rejection for many industrial, pharmaceutical and commercial applications.

While process cooling occurs in a dynamic environment, the primary components of an evaporative cooler are not configured to operate efficiently in varying conditions.

Many evaporative coolers installed today still have single-speed pumps and fans that are regulated from disjointed controls, while the processes that depend on these evaporative coolers have become ever more precise.

The scenario is like trying to get a modern jet aircraft fitted with a 50-year-old engine off the ground.

One can look back at advances in aviation to project what will benefit process cooling equipment.

Flaps, which are moveable wing surfaces, were once limited to what a pilot could crank down prior to take-off and crank up once airborne.

Likewise, cooling tower fans are pitched to run at one or two speeds.

Modern aircraft vary control surfaces to efficiently create lift throughout the flight envelope.

With the advent of AC drives (variable-frequency drives or VFDs), ordinary fans based on decades-old NACA airfoils are now confronted with operating in a dynamic environment.

Like modern avionics, today’s embedded controls are capable of economically and automatically adjusting fan blade pitch along with pumps, valve and auxiliary equipment operation.

In addition, advances in fan or fill engineering are incorporated by adding the knowledge base built into today’s unified embedded controls.

The cost benefit of using integrated controls alone can be significant.

As an example, a chilled water plant in which a 100hp pump was managed by an integrated control with a data feedback loop from a chiller and its cooling tower resulted in power savings exceeding 50 per cent for the pump.

Over the 15-year projected life of the equipment, nearly USD70,000 (GBP45,000) of savings are expected.

Payback on investment occurred within 11 months.

However, even greater energy savings over a broad range of operating conditions can be achieved by using fans with optimised airfoils and automatic adjustable pitch in combination with a VFD.

The payback would, again, be months rather than years.

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