Tour the Mechanical Room

Have you taken a virtual tour of our new energy-efficient Mechanical Room at the Taco Innovation & Development Center (IDC)?

We invite you to visit Center’s dedicated mechanical room, a showcase for the latest in energy savings and sustainable products and systems available in the HVAC industry today. The building includes advanced hydronics system applications such as radiant cooling, radiant heating, snowmelt, geothermal and solar thermal in a total of 25 “Living Laboratories” that provide for hands-on learning.

In this video, Rich Medairos, project mechanical engineer, walks you through the highlights of this sophisticated, integrated installation incorporating a variety of design strategies for an energy efficient building including:

• Active chilled beams.
• An energy recovery unit.
• Solar hot water generation.
• The iWorx system building management.
• High-efficiency pumps, chillers and boilers.
• Variable speed pumping applications.

Take a virtual tour now: http://bit.ly/O5e4Ev

Chilled Beams: A Viable Alternative to VAV Systems

Chilled Beams: A Viable Alternative to VAV Systems

By Greg Cunniff, Applications Engineering Manager, Taco, Inc.

Chilled beam technology works in tandem with a central air system, which is calibrated to circulate only the amount of air needed for ventilation and latent-load purposes. The chilled beams provide the additional air movement and sensible cooling/heating required through the induced room air and secondary water coil. As ventilation moves through venturi nozzles, creating a low-pressure zone within an active beam, room air is induced upward where it makes contact with the cooling coil. This air and primary ventilation air then mix and are delivered through linear slot diffusers.

The Convective Cooling Component is Natural Convection.

An active chilled beam will add considerable cooling capacity.

It’s in this way that active chilled beams transfer a huge portion of cooling or heating loads from the less efficient air distribution system to the more efficient water distribution system. As more systems are installed in the U.S. and Canada, it will become clear that chilled beam technology has developed into a viable alternative to conventional variable-air-volume (VAV) systems.

What makes this technology so interesting is its broad application for commercial structures and extreme energy and thermal efficiency. A key advantage is that a chilled beam system requires very little ceiling space and height. Another advantage is the high energy carrying capacity of water via pipes. A forced air system is significantly less efficient because of the low density of air, which necessitates large ductwork.

InEuropeintegrated/multiservice chilled beams have circulation systems incorporated into lighting, sound, sprinkler and cable pathways – in time we can expect this development to make its way across the pond to us as well.

Next up…In summary, benefits of chilled beam systems.

Passive vs. Active Chilled Beams

Passive vs. Active Chilled Beams

By Greg Cunniff, Applications Engineering Manager, Taco, Inc.

Chilled beams are available in three variations: passive, active and integrated/multiservice beams. The difference between passive and active beams focuses on the way airflow and fresh air are brought into the space. Both of these systems are now enjoying significant attention here in the U.S.and Canada.

Passive Chilled Beams - natural convection.

Passive Chilled Beams - natural convection.

Passive chilled beams require ventilation air to be delivered by a separate air-handling system. With active chilled beam systems – sometimes referred to as “induction diffusers” – a building’s ventilation air is continuously supplied to chilled beam terminal units by a central air-handling system. Ventilation is cooled or heated to partially handle temperature –driven sensible loads, while in summer it is sufficiently cooled and dehumidified to handle all of the internal moisture-driven latent loads. With active chilled beams, chilled beam air is introduced into the space through a slot diffuser creating a Coanda effect – that is, the tendency of a fluid jet to be attracted to a nearby surface like the ceiling.

Active Chilled Beams - forced convection.

Active Chilled Beams - forced convection.

Inducing warm air to blow through the chilled beam coil substantially increases its capacity. Active chilled beam capacities (in the range of 350 to 600 Btuh/sq. ft.) get a boost in capacity from the primary air from the DOAS. Depending on the temperature and the quantity of this primary supply air, the capacity can amount 300 Btuh/sq. ft. An active chilled beam can deliver from 500 to 900 Btuh sq. ft. between the chilled coil and the primary air.

Primary/ventilation is introduced into the active chilled beam through a series of nozzles. This induces room air into the chilled beam and, in turn, through a water coil. Induced room air is cooled and/or heated by the water coil and then mixed with ventilation air and released, which controls room temperature.

Next up…More on active chilled beams.


Hydronics Vs. Air: Radiant Cooling

By Greg Cunniff, Applications Engineering Manager, Taco, Inc.

In comparing hydronic chilled water and VRV/VRF systems, a new emerging factor for the chilled water side of the equation is radiant cooling. Radiant cooling is an exciting feature that avoids some of the challenges with space cooling distribution common to both types of air conditioning systems.

Comfort cooling is dependent on cooling coils and fans in the form of fan coil units or heat pumps along with filters (in the case of critical areas high efficiency filters). In lower end systems lower performance grills and air diffusers are commonly used, which can aggravate the comfort problem by dumping cold air on occupants. A radiant cooling system, however, avoids these problems since chilled air is not distributed through an air distribution system, as described above, but rather by a combination of radiant and natural convection. This only serves to improve IAQ.

Radiant cooling systems are now coming of notice here in the U.S. and design engineers are turning to them to achieve high comfort levels. Radiant cooling, like most hydronic-based applications, is common in Europe, but the trend line here in the U.S. is encouraging. There are a number of domestic radiant cooling manufacturers around today with successful installations.

At Taco’s Milton, Canada operation we have installed a chilled beam system to cool the office and training areas during the summer months.

Chilled Beam installation at our Taco’s operation facility in Milton, Canada

In this application active chilled beams were employed along with chilled ceilings to supplement. Together they work to reduce fan energy by a factor of 10, since the only air circulation that’s required is from the DOAS. This system supplies just enough treated, dehumidified outdoor air to slightly pressurize the building, negating natural infiltration of humid outside air. Like its counterpart, radiant heating, the market for radiant cooling will only grow larger in the years ahead, now that use of 100-percent DOAS is understood to be an effective remedy for the dehumidification issue previously associated with radiant cooling.

Lowering Peak Power Demand in Radiant-Cooling Systems

Lowering Peak Power Demand in Radiant-Cooling Systems

By Greg Cunniff, Applications Engineering Manager, Taco, Inc.

If the chilled-water flow of a radiant-cooling system can be reduced to that of a conventional system, peak power demand can be reduced even further. Injection pumping can achieve this goal. Injection pumping has been used in radiant-heating systems for a number of years, lowering 180°F boiler water to the 100°F-120°F needed for a radiant floor panel. The same principal can be applied to a radiant-cooling system in reverse by raising 40°F chilled water to the 55°F-60°F required by a chilled ceiling panel or beam.

The primary chiller flow in an injection-piping-system is lower than that in a conventional system. Primary chilled-water temperatures in an injection-piping system is 16°F – or 1.5 gpm per ton – while a conventional system ranges from 8°F-12°F – or 2-3 gpm per ton.  An injection-piping system’s flow rate is 50-percent less than that of a conventional system and 75-percent less than that of a typical radiant-cooling system. This results in a corresponding decrease in pump horsepower and materials for smaller pipe. An injection-piping system keeps the transport horsepower used to move a building’s heating and cooling energy to a minimum.

The use of low-temperature chilled water also allows spot dehumidification. A 100-percent DOAS pressurizes a building, negating infiltration of outside air. Natural infiltration can temporarily overwhelm the amount of outside conditioned air delivered by a DOAS when a building’s outside door is opened, especially in humid climates.

The amount of fresh air supplied to a building can be controlled by a differential pressure sensor to measure the difference in static pressure between the building and the outside. This sensor and an accompanying DDC controller will then control the speed of the DOAS unit fan to maintain a slight positive pressure. Fan coils can be used at the building’s entrances to overcome the inrush of humid air – or cold air in winter -that can overwhelm the slight building positive pressure when a door is opened.

A fan coil requires chilled water (50°F max.) to achieve adequate dehumidification, which cannot be supplied by a distribution system using 55°F-60°F chilled water for radiant panels and  chilled beams. With a proper low-flow piping layout, an injection-pumping system can deliver chilled water to building entrances for adequate dehumidification. Additionally, lower chiller operating temperatures (e.g., 40°F-45°F) allow a DOAS, rather than a direct-expansion unit, to use chilled water.

Next up… More on Passive Vs. Active Chilled Beams


The Evolution of Chilled Beams

The Evolution of Chilled Beams

By Greg Cunniff, Applications Engineering Manager, Taco, Inc.

European design engineers discovered that if they lowered chilled beams below a ceiling, each individual panel’s convection-cooling component could be increased. This satisfied the need for increased cooling loads caused by the expanded use of computers within the space. In addition, higher cooling capacities were needed for exterior zones to deliver better overall comfort. By lowering the panels, chilled panel capacity could be increased to approximately 120 to 150 Btuh per square foot of the beam or beam coil area. Also known as a passive chilled beam, this configuration resembles a beam when mounted below a ceiling and is passive because natural convection is the convective-cooling component.

The high cooling capacity of a passive chilled beam can help satisfy increased equipment loads in interior spaces and solar loads in exterior spaces. To further boost a passive chilled beam’s cooling capacity, conditioned ventilation air from a DOAS can be used to flow air through a chilled coil, further increasing the beam’s convective component. This configuration is known as an active chilled beam. Ventilation air is introduced to a chilled beam through a venturi, generating a higher velocity and, subsequently, a lower pressure region inside the chilled beam. This low-pressure region induces room air to flow up through the chilled coil and mix with primary air from the DOAS. The airflow over the chilled coil is reversed for an active chilled beam, and the induced room air flows up through the coil.

Active chilled beams sometimes are referred to as “induction diffusers.” Air from an active chilled beam is introduced into a space through a slot diffuser, creating a Coanda Effect. Inducing warm room air to blow through a chilled coil substantially increases chilled beam capacity. Active chilled beam capacities range from 350 to 600 Btuh per sq. ft. of beam or beam-coil area. Depending on the temperature and quantity of primary air supply from a DOAS, this can add up to 300 Btuh per sq. ft. of beam or beam-coil area. An active chilled beam can deliver from 500 to 900 Btuh per beam or beam-coil area between the chilled coil and primary air.

One thing radiant and chilled beam systems have in common is lower air volumes (1 to 2 ACH vs. 7 to 10 ACH). Lower horsepower and fewer materials are needed to achieve the same or better levels of comfort than with air systems, such as variable-air-volume (VAV), rooftop, variable-volume-and-temperature, and constant-air-volume systems.

The total peak power demand of radiant cooling system, including transport and generation systems, is almost 25% less than that of an all-air system. This decrease – which includes a 50% reduction in transport energy – is caused by the reduction of air quantities needed to cool the building. However, a radiant cooling system requires approximately twice as much chilled water flow as a conventional system, causing an increase in pump horsepower.

Next up…Lowering peak power demand.

Designing with Chilled Beams

DESIGNING WITH CHILLED BEAMS

As a manufacturer of hydronic equipment and systems, Taco has an active interest in all things concerning chilled beam technology, so we offer up this recent article in Engineered Systems magazine, entitled, “Practical Implementation of Chilled Beams for Offices,” co-authored by Peter Rumsey, P.E. and John Weale, P.E., both of the engineering firm Integral Group, based in Oakland, CA.

The authors provide a solid primer on designing chilled beam systems, which they consider a “mainstream solution for more efficient system designs,” and they emphasize that “careful attention to the design details (discussed in their article) can allow any engineer to add this efficient system type to his or her design box.”

 A bin analysis of three different systems.

A bin analysis of three different systems by Peter Rumsey P.E., FASHRAE John Weale P.E., LEED® AP (click on the image to enlarge)

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