The HVAC Factor: Heading Off Trouble With Technology
By Paul Michalicka
Originally published in the August 2011 issue of Today’s Facility Manager
Advanced maintenance and monitoring technologies can help facility managers (fms) improve the performance of HVAC systems and equipment. Tools featuring electronic and software innovations can help detect problems with machines prior to failure, reduce energy usage, eliminate labor-intensive tasks, and replace outmoded methods and procedures. There are a number of effective technologies on the market, and here are five that fms may benefit from having in their toolkits.
Laser equipped alignment systems. At many facilities, maintenance workers employ manual methods including straightedges to align shafts in coupled machinery (such as those found in electric motors connected to pumps or fans). But manual methods can result in misalignment, causing machine vibration and increased energy consumption. Advanced shaft alignment systems with built-in laser sighting offer greater accuracy. The latest systems typically feature a handheld display unit and dual measuring units positioned a few feet apart on the coupled shafts (see photo above). Each measuring unit emits a laser line, which is projected toward the opposing unit’s detector. “Live” values appear on the display to guide alignment, and the coupled shafts are adjusted vertically and horizontally until aligned.
Fms may also benefit from laser equipped alignment systems for belt driven machinery. Systems that align the grooves of opposing pulleys (rather than pulley faces) offer accuracy regardless of pulley thickness, brand, or type. These systems usually consist of a laser emitting unit and a receiver with a target area that can detect horizontal, vertical, and parallel misalignment.
Automatic lubricators. Rolling bearings and other components in HVAC applications (such as blowers and pumps) need periodic relubrication. That often requires maintenance staff to relube dozens of rotating machines manually. One labor-saving solution is to use automatic lubricators that accurately meter out lubricant for long periods without requiring maintenance.
Recently, a 2,000 bed hospital in Vienna, Austria improved fan operation and reduced labor costs by installing high accuracy multipoint automatic lubricators. Previously, staff there manually relubricated the facility’s 200 fan applications, a time-consuming procedure. Also, the practice commonly resulted in undergreasing, leading to premature bearing failures.
To address this, the hospital ran a six month test program with about 50 multipoint automatic lubricators. Each lubricator featured a centralized canister holding more than 400 milliliters of grease which could operate for a year without replenishment. Lubrication intervals and quantities were carefully calibrated. The lubricators supplied an accurate, regulated flow of grease to fan bearings through up to eight feed lines per canister, preventing overgreasing and undergreasing. After the test, the facility expanded automatic lubrication to all 200 fan applications.
Ultrasonic leak detectors. Fms can also consider ultrasonic leak detectors for HVAC maintenance. As gases escape from a leak, they generate a turbulent flow with high frequency characteristics. The same is true of fluids escaping a leaking valve. Ultrasonic detectors sense these high frequency sounds, convert them to audible signals, and alert users to leak locations.
Some detectors include pistol type probes equipped with noise isolating headsets. Maintenance workers can employ the probes to scan a target area for leaks, and when leaks are detected, they are audible as rushing sounds over the headset.
Ultrasonic detectors can find pressure and vacuum leaks in heat exchangers, boilers, and condensers. They are also recommended by steam trap manufacturers to identify common trap conditions (e.g., blow by, line blockage). The detectors can also provide early indication of bearing problems and perform general mechanical inspections of pumps, motors, compressors, and gearboxes. They also pick up electrical discharges from transformers, circuit breakers, and related equipment.
Thermal cameras. Thermographic technology has improved significantly in the last decade and grown more affordable. Resembling digital cameras in size, new generation thermal cameras detect thermal energy in the spectrum’s infrared band, allowing users to identify temperature anomalies or “hot spots” in operating machinery. Fms can employ the cameras to detect overloads in electrical equipment or to spot overheating in motors or fans. The thermal images are instantly shown on the camera’s viewing screen.
A recent development is a pocket size infrared detector, a non contact instrument that senses thermal energy radiating from equipment and measures the surface temperatures of hot or hard to access machines from a distance. Built-in dual lasers allow users to aim and highlight a targeted area. From 10′ away, the detector can measure thermal energy radiating from an area measuring 2.4″ across.
Video endoscopes. These tools can supplement other monitoring methods by revealing the internal conditions of HVAC machines and components. They generally feature a palm size display unit attached to a flexible insertion tube that measures one meter (3.2″) or more in length. The insertion tube is equipped with a miniature camera and LED lighting and is threaded into ports in machines such air conditioner compressors, gearboxes, and bearings. This allows staff to view still or video images on the display unit in real time and then upload the images to PCs for further analysis.
Many fms find some manual maintenance methods to be tried and true. However, the technology available in some tools today can make the job of keeping HVAC systems up and running easier and more accurate.
Michalicka is North American area sales manager for maintenance products at SKF USA Inc., which is based in Kulpsville, PA.