4 FM quick reads on HVAC
1. Water Treatment Records Are Not Just Busy Work
Today's tip comes from James Piper, contributing editor for Building Operating Management.
One of the most important procedures for the long-term effectiveness of the water treatment program is good record keeping. Thoroughly documented logs of test results and actions taken will not only provide a clear indication of the status of the program, but also indicate any trends that are taking place. In the event of a component failure, a review of records can help identify the cause and what can be done to prevent a recurrence. Good records also help operators predict problems with system components and to identify those that should be inspected.
Here are four types of records that should be kept:
• Makeup water: quantity used, hardness, conductivity and silica
• Cooling tower water: pH, hardness, silica, conductivity, and inhibitor and bacterial levels
• Closed-loop systems: pH, conductivity, iron, hardness, and inhibitor and bacterial levels
• Chemical treatment: chemical pump settings and dosages
Infrared Cameras Can Help Find Leaks in Ductwork
Today's tip is finding leaks in HVAC ducts.
Leaking ducts can be a pernicious energy waster. They lose heat or cooling &emdash; into the ceiling plenum or other space &emdash; rather than delivering it to occupied areas. What's more, they increase fan energy use because more air has to be moved.
Infrared cameras &emdash; more formally known as thermal imagers &emdash; offer an easy way to find leaks in ducts. The cameras capture an image of heat patterns in objects. An image of a duct would show hot and cold spots, allowing the facility staff to pinpoint leaks in the duct.
Advances in technology have produced cameras that are smaller, offer better resolution, have more features, and cost less than cameras in the past.
Repairing leaks in ducts can produce significant savings. That's because fan energy use is proportional to the cube of the speed of the fan, so they become more efficient at lower speeds. Once duct leaks are repaired, fans will save energy because they are moving less air and moving it more efficiently.
Retrocommissioning Quickly Pays for Itself in Energy Savings
Today's topic is payback for retrocommissioning.
Problems with controls &emdash; HVAC controls in particular &emdash; can waste energy and raise operating costs significantly. The way to find and fix those problems is well-established but too rarely used. Retrocommissioning applies the principles of commissioning to existing buildings rather than to new ones. Studies have shown retrocommissioning to be a cost effective way to improve the performance of controls and to remedy other problems within a building.
Retrocommissioning takes a relatively modest upfront investment. According to a study by Lawrence Berkeley National Laboratory (LBNL), the average cost for retrocommissioning is $.30 per square foot. But the return on that investment comes quickly: The median payback time is a little more than a year. That's not surprising considering that the median energy savings is 16 percent. And those savings last, says LBNL: "Energy savings tend to persist well over at least a 3-to-5 year timeframe." Savings may last longer than that, but the study didn't have data for longer periods.