While Australian building professionals haven’t fully embraced the concept of thermal mass linked radiant cooling or heating in commercial building designs, they have started to explore technology known as Chilled Beams.
This is largely due to the benefits it delivers to the overall energy performance and long term sustainability in new and renovated buildings.
It is a viable alternative to the conventional and widely used fan coil or variable air volume (VAV) HVAC systems currently used to condition indoor air.
This article introduces chilled beams and LoFlo Injection pumping.
It will outline this type of convection air conditioning and Hydronic systems which are designed to heat or cool commercial buildings in an energy efficient and sustainable manner.
So what is a chilled beam?
To simplify the definition, a chilled beam is a type of air conditioning system designed to heat or cool large buildings.
Copper pipes carrying chilled or heated water are passed through a “beam” (a heat exchanger/ radiator) suspended a short distance from the ceiling of a room.
As the beam cools the air around it, the air becomes denser and falls to the floor.
It is replaced by warmer air moving up from below, causing a constant flow of convection and cooling of the air in the room.
The heating cycle delivered though active chilled beams, works in much the same fashion, except it is delivering warm air into the working or living space.
There are three types of chilled beams. These include passive, active and multi service.
The difference between the passive and active beams, both of which are receiving significant interest locally, concerns airflow and the way fresh air is delivered into the airspace.
With a passive chilled beam system (suitable for cooling only), outdoor air is supplied into the airspace through a separate diffuser or grille.
With active chilled beam systems (suitable for both heating and cooling), outdoor air is supplied into the airspace through the beam itself.
Multi service chilled beams can be of bespoke design and incorporate light, sound, fire and cable pathway services required for the building. These types of chilled beams are widely used throughout Europe.
What makes this technology so interesting is its broad applicability 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, thus enabling shorter commercial buildings but offering the same floor space for tenancy.
Another advantage is the high energy carrying capacity of water via the copper pipes.
A forced air system is significantly less efficient because of the low density of air, necessitating large ducts and taller, less efficient and costly buildings to deliver the same conditioning of the indoor air.
The amount of outside air required to operate a typical chilled beam system is much less than that needed for a forced air system.
A chilled beam system typically needs only one air change per hour, using outside air to pressurize the space.
With a forced air system, that need grows to eight to 10 air changes of recirculated and fresh air into the space.
With active chilled beam systems, energy to operate fans is reduced dramatically because of the low pressure and the relatively small amount of primary air being circulated by the central system.
A chilled beam system can reduce electrical energy demand by almost 25 per cent.
Coupled with the Chilled Beam, Ravenscroft Australia together with Taco Inc. have introduced a variety of new “Green” Hydronic products and system concepts that yield dramatic benefits over the traditional and conventional airside and Hydronic designs of the past.
Just arriving in the Australian market is the award-winning Taco LoFlo Mixing Block (LMB) which sets a new standard for comfort, ease of design, and superior energy performance in Hydronic systems for small to large commercial buildings.
The LoFlo Mixing Block can easily be incorporated into new and existing radiant heating and cooling systems for cost effective results in a variety of applications.
When employed in conjunction with Taco’s latest system approaches, outstanding benefits accrue to designers, installers, owners, and users alike.
Installed within modern radiant systems such as Chilled Beams (active or passive), only two chilled water pipes are needed compared to the conventional four pipe system.
Water flow rates are reduced since there are no control valves, balancing valves, or piping losses to overcome. The small, reliable circulators take the place of all of these components.
The LMB automatically provides only the flow and temperature of water needed to satisfy the zone load at any given time.
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