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Cooling Buildings using Radiant Technology

The second law of thermodynamics states that thermal energy will always move from an object of higher temperature to one of lower temperature until the two reach equilibrium. This transfer of heat can happen in three ways: conduction (direct contact), convection (fluid motion) & radiation (electromagnetic waves).

We traditionally think of radiant systems as being used to heat spaces. But we can actually design radiant systems for effective cooling as well. Radiant heat transfer does not require any medium or physical contact to transfer thermal energy where as the traditional convection method does.

More airtight building envelopes and improved direct outside air systems have been used to manage indoor humidity while providing fresh air. This has helped to make radiant cooling become a viable option. A radiant system using water as its medium can transport more thermal energy per unit of volume than air via convective systems. And since ventilation is decoupled from thermal conditioning in a radiant system, much less air needs to be supplied to occupied spaces, thus reducing the total amount of energy required to power fans moving thermal energy throughout a building.

In a radiant system, hydronic tubing can be embedded or attached to different types of floor or ceiling assemblies. This allows hydronic radiant systems to offer many advantages over air-based convection systems including a higher level of thermal comfort, significant operational energy savings, and greater ease of maintenance for such conditioning systems.

With radiant systems engineers must design to control moisture with a conditioned supply of outside air and take care to ensure the temperature of chilled water for the radiant cooling system remains a few degrees above the interior air's dew point. This requires the use of temperature and humidity sensors at key locations.

Radiant cooling & heating systems are well suited to large multi-height and highly glazed circulation spaces. During the winter season, heating the floor through radiant means ensures that thermal energy reaches the occupants immediately instead of being quickly carried to the ceiling (which is a common occurrence with convection forced-air systems). In the summer months thermal energy delivered to the floor can be removed by the radiant cooling system before occupants start to feel the heat (although a more effective solution would be the use of exterior shading systems to prevent this problem). In contrast, radiant ceiling panels can be suitable in spaces that are subdivided by workstations because they provide a large, uninterrupted thermal surface from above.

In conclusion, the passive approach of radiant cooling can save on energy costs as well as create a higher level of thermal comfort. As our society moves forward into a more sustainable future the benefits of using this strategy can help us reduce our dependence on non-renewable energy resources as well.

Call MSA today at 210.408.7533 or use the contact form to discuss putting radiant technology to work in your business.