Radiant Cooling Takes Hold In Canada
Taco conditions its 30,000-sq.-ft. factory-warehouse-office space with chilled panels and beams.
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| Taco tested a radiant cooling system at its Canadian sales and distribution facility. |
When Taco Canada relocated its sales and distribution facility in 2008 to Milton, Ontario, Canada, it installed a prototype radiant cooling and heating system in the new office. The headquarters became a logical choice to test the operational efficacy of the system.
Commercial radiant cooling has been in existence since the 1980s, centered mostly in Europe. It has developed to the point where, with the use of today's active chilled-beam technology, it can provide full indoor comfort cooling.
Taco's LoFlo radiant cooling system uses a mix of products, including fan coils, heat pumps, chilled ceiling panels, active and passive chilled beams, a single-pipe circulation system, and a modified radiant-cooling injection pump version of its popular radiant mixing block (RMB).
System components are linked in the same piping distribution system despite each of the terminal units requiring different temperatures. The radiant cooling system works in conjunction with radiant chilled ceiling panels and passive/active chilled beams, along with a 100% dedicated outside air system (DOAS) to supply latent cooling.
The office portion of the 30,000-sq.-ft. building is seasonally conditioned by 21 heating and 21 cooling zones. The system was designed not only for an operational role but also for training and display purposes. For example, all of the system components and piping were mounted exposed on the partition wall between the office area and the manufacturing/warehouse space.
There are two separate side-by-side loops for heating and cooling. Thermostats feed into a building-automation system to regulate the indoor temperature. A rooftop chiller and a heat exchanger provide water at 42 F for cooling.
The LoFlo mixing block (LMB) circulates water to the terminal units. The LMB consists of a zone circulator, for water flow through the secondary circuit to the terminal units, and a variable-injection pump that takes a signal from the building-automation system to inject cold water to always maintain the above-dew-point system temperature.
Because the chilled-water supply temperature provided to a radiant-chilled ceiling is above the dew point, radiant-chilled panels alone cannot provide sufficient latent cooling capacity. Providing a 100% DOAS to accomplish latent cooling allows the combination decoupled system to provide sensible and latent capacity. Dedicated outside latent-load air is pretreated and delivered to the terminal units as sensible cooling.
Taco's LoadMatch circulator eliminates control valves and most balancing valves, and greatly reduces piping. The system delivers heating and cooling energy to a variety of terminal units, all in the same piping-distribution system, despite the requirement for different temperatures at different terminal units.
In general, hydronic systems use approximately half the horsepower and half the materials to move heating and cooling around a building, compared with air systems. The LoFlo system uses only a third of the energy and materials to move heating and cooling energy. For example, the system uses only one to two changes of outside air flow/hr. compared with 8 to 12 air changes/hr. for an all-air system. As a result, there is a substantial reduction in the transport energy, or horsepower, to move BTUs around the building. This savings can approach a fourth of the total HVAC energy in a building over a variable-air-volume system. The LoFlo system savings will approach a third of the total HVAC energy.
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