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Trox USA Chilled Beams

The German company Trox makes a variety of passive and active chilled beams for commercial use… Read more
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  • Before specifying efficient heating and cooling equipment, it’s important to do what we can to reduce heating and cooling loads. Insulation is one of the key products to consider here, but because there are so many insulation products on the market, we look for additional benefits. Examples include cellulose insulation with recycled content, mineral wool insulation with no flame retardants, and fiberglass insulation with no formaldehyde binders. Other products in this area are high-performance windows and glazings, products that contribute to building airtight envelopes, products that reduce thermal bridging, and window-retrofit products.

    With products in this area under constant development, we are always refining our approach. For example, as we have learned about insulation products with hazardous flame retardants and blowing agents that have high global warming potential, we have removed those products from GreenSpec, pending manufacturing changes. We encourage building professionals to pressure manufacturers for those changes through specification language and purchasing decisions.

  • With energy-consuming equipment, such as water heaters and refrigerators, we have good data on energy consumption and can set clear standards accordingly. In some product categories—clothes washers, for example—Energy Star standards were adopted because those standards provide a high enough threshold to represent just the very top segment of the product market (less than 10%). In other product categories—e.g., refrigerators and dishwashers—we set a higher threshold than ENERGY STAR: for example, exceeding those standards by 10% or 20%. With lighting and lighting control equipment, certain generic products qualify, such as compact fluorescent lamps and occupancy/daylighting controls, while in other categories only a subset of products qualify. In some cases, products that meet the energy efficiency requirements are excluded, because of evidence of poor performance or durability. Microturbines are included here because of the potential for cogeneration (combined heat and power) that they offer.

The German company Trox makes a variety of passive and active chilled beams for commercial use. Primarily used for high-cooling-load applications, passive beams can be mounted either flush to the ceiling or extended beneath. The company offers active beams that provide cooling and heating and can be installed using either side or top fresh-air entry; some that are appropriate for low-ceiling-height construction; and multi-service models that incorporate lighting and other features. Smaller models are also available for use in individual rooms, such as in hospitals, and there are higher-capacity models for use in spaces with taller ceilings.

Chilled beams are typically ceiling-mounted fixtures that use chilled water flowing through finned heat-exchanger coils to supply cooling (and sometimes heating) in large commercial buildings. Chilled beams take advantage of water’s ability to transport energy more efficiently than air. Pumps also move water more efficiently than fans move air. Chilled beams require very little ductwork and fewer mechanical systems, which can save significant building space Chilled beams work best with ceiling heights of less than 14 feet, and building humidity levels have to be carefully controlled to avoid condensation.

Passive chilled beams operate through simple convection: as warm room air rises it passes through the water-cooled heat exchanger fins inside the chilled beam where it cools and settles back into the room. This air pattern circulates the cooling energy. Passive beams can provide an energy-efficient HVAC solution, especially in retrofits or modular office layouts where duct space is a problem, but they require added ventilation—often underfloor—to provide fresh air and humidity control, and they do not provide heating.

Active chilled beams (ACBs) use the same heat-exchanger technology as passive beams, but can supply both cooling and heating, as well as ventilation air. ACBs contain an added compartment (plenum) that is connected to the ventilation air supply. This primary ventilation air (dehumidified and filtered outdoor air) enters the beam’s plenum under pressure where it is forced through nozzles that direct the flow of the air along the outside of a second chamber and into the room.

This action pulls secondary air (room air) into the unit from underneath via induction past the heat exchanger coils. This secondary air, now cooled or heated, mixes with the primary air in this second chamber and is blown back into the room. Unlike passive beams, active beams force warm air down into the room rather than relying on convection, so they can provide heating as well as cooling. There are no electrical connections or moving parts in the beams, minimizing maintenance and creating a quiet HVAC system. (There are also custom, multi-service ACBs that include lighting, sprinklers, security, sensors, or other features.)

Radiant ceiling panels are similar to chilled beams, but use flat panels instead of finned heat exchangers. They are less efficient than chilled beans and do not supply ventilation air. They could be a viable choice in the right building, but GreenSpec does not list radiant ceiling panels.

LEED Credits

EAc1: Optimize Energy Performance

EAc1.3: Optimize Energy Performance—HVAC

EAp2: Minimum Energy Performance

EAp2: Minimum Energy Efficiency Performance

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