Although radiant distribution technology for heating and cooling has existed for more than a century, many people still don't understand how and when it should be used. Misconceptions around its effectiveness, how it works in different climates, and benefits are all reasons for this confusion.
However, appropriately designed, a radiant heating system can be used in nearly all climates as an efficient commercial HVAC system. You’ll find radiant cooling systems as far north as Canada. The differences between radiant heating and conventional HVAC systems are many, so choosing between the two requires careful consideration of project requirements.
All HVAC systems are designed to change temperatures in various rooms. The most common systems use a forced-air system: for heating purposes, the air is blown (over a furnace, through a hot water coil, or over the evaporator coil of a heat pump), then supplied throughout a building through a system of ducts and supply diffusers.
While a radiant heating system can use a similar boiler, it can also use a geothermal system or heat pump to warm up water or another fluid. Small pipes, often three-quarters of an inch, move the fluid through floors, wall panels, or ceilings depending on the system installed. The water then raises the temperature of those elements, which provides radiant heat (technically, there may also be an element of convection) to occupants in the line of sight of the element.
A radiant cooling system uses similar piping systems, but the water is cooled and then delivered through the same types of piping found in radiant heating systems.
In either case, the system’s installation is the final difference: most radiant systems are installed in either floors or ceilings. Floor-based radiant systems can be formed by installing tubes running through a concrete floor slab or a smaller sub-floor. The slab is essentially heated or cooled to provide the radiant effect. Ceiling panels are “activated” by running hot water or chilled water piping attached to the back of the panel. The panel then becomes the radiating element. Below are examples of a radiant system installed in office spaces.
In commercial HVAC applications, the biggest differentiator between these systems is whether the mediums for heat transfer will be air or liquid. Radiant distribution systems will either use warm water or cool water passed through piping in floors, baseboards, or ceilings. The effect on occupants is perceived as more gentle because there is no actual warm or cold air blowing over them.
There are also physical differences. Water has a higher energy capacity than air, so the system does not need as much physician space to transfer the same amount of cooling or heating capacity. In addition, the physical piping required to produce the same heat transfer is much smaller than the ducting required to create a similar effect. Two 1” pipes deliver through a building approximately the same heating capacity as a 2’ x 2’ duct.
A major constraint in any commercial HVAC design is cost, and radiant distribution systems for heating and cooling require special consideration compared to forced-air systems. While radiant heating is generally useful throughout the US and Canada without many issues, radiant cooling comes with special consideration associated with indoor humidity levels. More specifically, humidity and dew point levels must be addressed with radiant cooling systems outside of arid regions like the southwest United States. If space air, or ventilation air introduced into the space, does not have a dew point above the radiant panel surface temperature, the panel may form condensation that can cause water damage.
In addition, HVAC design engineers simply have not seen as many projects in which radiant systems are desired. Radiant cooling systems are even less commonly specified. As a result, the propensity to see radiant designs is diminished.
Are radiant distribution systems the right fit for your heating and cooling needs? At Windy City Representatives, we can help you find the ideal fit. Contact us today to start your search. We look forward to matching you with the right fit for your budget and HVAC performance envelope. Windy City Representatives partners with premier providers of radiant cooling and heating systems, especially Barcol-Air.
630-590-6933
