Chapter 5.1.3 - Radiant Panel Systems Evaluation

There are many advantages unique to radiant panel systems. The authors have
included those recognized in ASHRAE Handbook Fundamentals, research, and manufacturers’
literature. The importance of each feature will vary with the application
and geographic location. However, a full understanding of the impact of radiant panel
features on design comparison is essential to a robust comprehensive evaluation.

Radiant panel evaluation features include the following:

• Better comfort levels because radiant loads are satisfied directly and air motion is
  at normal ventilation levels.
• Energy savings due to reduced air infiltration and exfiltration, lower or nonexistent
  heat transmission losses compared with ducted systems, and lower heat loss
  due to dry-bulb air temperatures that are no higher than the level required for
  occupant thermal comfort.
• Low or minimal maintenance is required for radiant panels.
• Reduced air filtration as makeup air is required only for ventilation and not for
  deliveries of heat as forced-air systems require.
• One hundred percent usable floor space and simplified wall, floor, and structural
  systems because there is no space-conditioning equipment at the outside walls.
• Cleanliness due to elimination of mechanical equipment in the conditioned floor
  space satisfies certain legal requirements.
• Window treatment freedom as installation is not restricted by space-conditioning
  equipment.
• Simultaneous hydronic heating and cooling without central zoning or seasonal
  changeover when a four-pipe system is used.
• Common central air system can serve both interior and perimeter zones.
• Space partitioning and use flexibility with modular radiant panel systems.
• Reduced air quantities for 100 percent outside air systems mean smaller penalties
  in terms of refrigeration load.
• Draft-free environment due to a minimum supply of air quantities with radiant
  heating and cooling.
• Little or no noise compared with induction and fan-coil units.
• Peak load reduction due to mass thermal energy storage in the panel structure,
  exposed walls, partitions, and furnishings.
• Hybrid system problem solving when coupled with other conditioning systems for
  heat loss (gain) compensation for cold or hot floors, walls, windows, skylights, fireplaces,
  or other cold surfaces.

Radiant panel disadvantages include the following:

• Slow response is a characteristic of high-mass systems that can be ameliorated by
  careful selection and installation of heating elements and controls.
• Nonuniform surface temperatures due to improper element sizing, piping installation
  spacing, or insufficient heat capacity.
• Options may be restricted for building materials selection, floor coverings, furnishings
  location, and heater proximity.
• Renovation, redesign, and furnishings options and costs may be impacted.

Radiant heat panels provide natural, direct source-to-object heating that does
not require a heat transfer medium. A radiant panel is noiseless, odorless, and generally
maintenance-free. Panel design and planar location establish basic heat transfer
characteristics that can be managed by thermostats, and fluid controls in the case
of hydronic systems.

There are many advantages unique to radiant panel systems. The authors have
included those recognized in ASHRAE Handbook Fundamentals, research, and manufacturers’
literature. The importance of each feature will vary with the application
and geographic location. However, a full understanding of the impact of radiant panel
features on design comparison is essential to a robust comprehensive evaluation.

Radiant panel evaluation features include the following:

• Better comfort levels because radiant loads are satisfied directly and air motion is
  at normal ventilation levels.
• Energy savings due to reduced air infiltration and exfiltration, lower or nonexistent
  heat transmission losses compared with ducted systems, and lower heat loss
  due to dry-bulb air temperatures that are no higher than the level required for
  occupant thermal comfort.
• Low or minimal maintenance is required for radiant panels.
• Reduced air filtration as makeup air is required only for ventilation and not for
  deliveries of heat as forced-air systems require.
• One hundred percent usable floor space and simplified wall, floor, and structural
  systems because...