Developments in HVAC: Chilled Beams and Energy Recovery

Outside units on the roof of a Century Bank

Editor’s note: This article first appeared in the July/August 2015 issue of edition of Business Energy.

There has been a lot going on in recent years related to advancements in commercial HVAC.  A previous article examined variable refrigerant flow (VRF).  Today, we’re going to look at chilled beams and energy recovery. Some of the systems that are new to the US have been used successfully in Europe for decades, and others are brand new technologies still making their way into the sectors that can benefit most from them.

Chilled Beams
Another innovative HVAC technology is chilled beams, which work by convection. The beams, suspended from the ceiling, chill the air around them. The cool air is dense and thus falls to the floor, and warmer air rises up. Overall, there is a passive, constant flow of cooling air. There are active versions of the technology, too, which push air toward the units.

“We are the first US manufacturer of chilled beams,” says Tom Rice, director of sales for SEMCO. “We manufacture the beams as flexible as possible for ease of design and contractor installation.”

The company’s newest related product is called the Neuton pump module, which is coupled with chilled beams. “You can have a central plant that is creating 45-degree [Fahrenheit] water, and feeding that to all of the air handling units,” says Rice. “With chilled beams, you need 58-degree [Fahrenheit] water. So, you can create a blend loop, which blends the 45-degree water to where it becomes 58-degree water, and this is fed out to the chilled beams. This is called a tertiary loop.”

The Neuton creates a tertiary loop at the zone level, rather than at the full-building level. So, if one zone has a problem, such as the rising humidity, the pump module addresses that one zone, as opposed to the central tertiary loop, which would affect all of the zones.

“This zone approach provides a lot of energy savings,” says Rice. “In addition, the pump system controls allow the facility to save on first-cost from the piping perspective, from the electrical perspective, and from the control perspective.”

Energy Recovery
Besides chilled beam technology, SEMCO also offers energy recovery technology for HVAC systems. Its new Unitary Wheel Cassette (UWC) Series, an aluminum energy recovery dessicant wheel, is designed as the HVAC industry’s first drop-in replacement for plastic/polymer dessicant wheels in most unitary energy recovery ventilator (ERV) brands.

The wheel features a fast-acting and corrosion-resistant dessicant that is applied to a sturdy but lightweight all-aluminum wheel substrate. The honeycomb matrix’s opening design produces maximum air-to-air heat transfer, but generates up to 50% less HVAC system static pressure than polymer film wheels. It also has a longer life cycle and less periodic maintenance requirements than polymer wheels.

“The marketplace is filled with inexpensive plastic wheels that have a very short lifespan—one to three years,” says Rice. Since the units could last 15 years, it required a lot of time and money to continually replace the wheels. “In addition, plastic is not a good conductor of energy. So, our goal was to develop an aluminum drop-in replacement wheel that could replace these short lifespan wheels that no longer worked. Aluminum, of course, is a good heat transfer device.”

It is important to consider recovery energy ratio (RER) when purchasing replacement wheels. The RER takes into account the efficiency and static pressure of a dessicant wheel replacement. Not calculating the RER can result in thousands of dollars of lost energy savings over the course of the wheel’s life cycle. “The RER on our wheels, in some cases, is double what our competitors’ wheels produce, because ours use much less energy to recover exhaust energy,” says Rice.  BE_bug_web

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