Radiant systems have successfully been used in Europe for more than 15 years as a standard practice of energy efficient cooling and heating.

Traditionally, radiant systems have been used for heating by circulating a heated fluid through PEX or copper pipes placed within a floor, wall or ceiling structure. We use KaRo capillary tubes both for heating and cooling applications. In the case of heating, the radiant energy transfer is caused by a warm surface of capillary mats giving up its heat to a cooler surface (your body). This radiant energy travels through space without heating the space itself. It only turns into heat when it contacts a cooler surface. Radiant cooling works very much the same way, except the heat transfer is in the opposite direction. Instead of a heated fluid, a chilled fluid is circulated through capillary tubes above drywall/plaster or ceiling panels located in the ceiling. The cold capillary mats above drywall/plaster ceiling then absorbs the thermal energy radiating from people and their surroundings (sensible load), lowering the mean radiant temperature of the room.

The major difference between cooled ceilings and air conditioning is the heat transport mechanism. Air conditioning uses convection only using air distribution through ductwork, but radiant cooling uses a combination of radiation and convection. The amount of radiant heat transfer can be as high as fifty five percent, while convection accounts for the remainder.

Cooling nonresidential buildings in the U.S. contributes significantly to electrical power and peak power demand. Part of the electrical energy used to cool buildings is drawn by fans transporting cool air through the ducts. Traditionally, HVAC systems are designed as all-air systems. Hydronic radiant systems are air-and-water systems that separate the task of ventilation and thermal space conditioning by using the primary air distribution to fulfill the ventilation requirements, and the secondary water distribution system to thermally condition the space. These systems reduce the amount of air transported through buildings significantly, because the ventilation is provided by outside air systems without affecting the recirculating air.

Radiation provides most of the cooling, using water as the transport medium. Thanks to the physical properties of water, hydronic radiant cooling systems can remove a given amount of thermal energy using less than 5% of the fan energy that would otherwise be necessary. The separation of cooling and ventilation task not only improves comfort conditions, it also improves indoor air quality as well as the control and zoning of the system.

Another benefit is that the ventilation systems (DOAS System) and their duct work need only about 20% of the space requirements of conventional HVAC systems, reducing cost for hydronic cooling. Togather with efficient ventilation systems and humidity control, the hydronic radiant cooling system provides advantages over conventional HVAC systems that are worth considering during the building design.

KaRo mats used for cooling mainly used in public buildings. These includes: hospitals, office buildings, libraries, museums and nursing homes. Same KaRo mats can be used both for heating and cooling. Proper piping configuration is required to achieve this.

Finally a single system provides both heating and cooling through a hydronic distribution system. Water is distributed through capillary tubes approximately 1/16-inch in diameter and spaced at about ½-inch apart. The capillary mats are embedded behind drywall/plaster or a metal ceiling.

Radiant Cooling Corporation (RCC) offers a unique blend of design, estimating, product delivery, installation and maintenance of KaRo systems, bringing your new project into the 21st century.