Radiant Passive Chilled Beams are a 'hybrid' between a traditional Passive Chilled Beam and a Radiant Cooling Chilled Ceiling. Chilled water is circulated through the Radiant Passive Chilled Beam such as FTF Group's 'X-Wing®' unit which consists of a single serpentine sinusoid coil (X-Wing® has no joints in the copper coil to eliminate any risk of leaks) with 4 gilled aluminum fins mechanically joined to each waterway. The fins are equally spaced and run longitudinally to each waterway, thus forming an 'X' cross-sectional profile with a waterway in the center, hence the name 'X-Wing®'.

As chilled water is circulated through the copper water pipes, the aluminum becomes colder than the room space, thus cooling any air that comes into contact with the cold surfaces, this is the convective quotient and this represents 60% of the total cooling from the X-Wing® unit. The other 40% of total cooling comes from 'radiant absorption' which cools the occupants and room space without the air movement that is associated with convective cooling, hence higher total cooling allowed with radiant convective cooling (336 BTU/hr/ft) as opposed to traditional convective only cooling which is limited to 232 BTU/hr/ft to avoid excessive air velocities - see 'What is radiant absorption cooling'.