4  FM quick reads on HVAC

1. Benefits of Submetering Central Plant Can Justify Cost

Today's topic is the value of submetering the central plant.

The chiller plant is likely to be one of the facility's largest energy users, and often the largest. That makes it a good candidate for submetering.

The biggest obstacle to submetering is typically cost. But submetering the chiller plant offers a range of important benefits that can justify the cost. Perhaps most important is that it enables facility managers to analyze the energy consumption of the central plant. For example, if chiller plant energy use climbs from one spring to the next, it may be that outside air economizers aren't working properly. Or a change in operations or a problem with controls may have caused a spike in electricity use. Addressing problems like those can bring significant savings.

Data from submeters can be used to test the effectiveness of various operational measures designed to save energy and to verify whether upgrades have actually performed as expected.

What's more, submetered data may help to identify problems with equipment. Addressing those problems may not only save energy, but prolong the life of the equipment or identify a piece of equipment that is failing.

Finally, in a multitenant building, the use of submeters can be an element in an overall energy efficiency or green strategy used to attract and retain tenants.

Portable Cooling Units One Option In Data Center HVAC Control

I'm Justin Smith, managing editor of web development for Building Operating Management magazine. Today's tip: portable cooling units in data centers. As technology advances and hardware becomes more powerful, the issue of cooling data centers continues to heat up. There's a simple logic to the situation: as facilities add more equipment, the greater the cooling needs will be. One solution is to add a portable cooling unit to your facility. These units can be permanent or temporary and generally are used where known hot spots exist in rooms where large, capital-intensive cooling solutions are not possible. Portable units can supplement existing HVAC systems and installations can be scheduled when maintenance tasks require the shutdown of the main system. In general, the units can be air- or water-cooled, capacities can range from 0.5 to 5 tons and they can be wheeled or ceiling-mounted. Costs can range from $600 to more than $12,000 per unit. So, whether for a temporary fix or a permanent addition, portable units in data centers are a cool idea.

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.


HVAC , chillers , submeters , energy efficiency

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