Radiant Ceiling Heating / Cooling Systems Year round radiant comfort. Radiant Ceiling heating and cooling

Talbott Solar & Radiant Homes in Davis California  is a construction and consulting firm, specializing in residential and commercial hydronic radiant ceiling heating and cooling systems. For engineering assistance please contact the National Radiant Design Center (831) 333-1130. For information about radiant ceiling heating and cooling modules visit xLath.com Do you know anyone who is not satisfied with the comfort delivered by their heating and cooling system? According to surveys performed by organizations such as;  National Association of Home Builders and Professional Builder and Contractor magazine, approximately half of building occupants are not satisfied with the comfort of their building. Conventional heating and cooling design practice considers convection and conduction for delivering comfort, ignoring Mean Radiant Temperature (MRT).  Building heating and cooling design standard ASHRAE 55-92 Thermal Environmental Conditions for Human Occupancy, identifies MRT as an important factor in comfort. In other work MRT is identified as contributing 50% of the comfort equation. Clearly building designers can deliver more comfortable buildings by including radiant space conditioning.

Talbott Solar and Radiant Homes Inc. has won several Radiant Cooling awards, the Green Entrepreneur Award in 2006 and System Showcase in 2006, 2008-10.

Conventional Housing Hydronic Radiant Ceiling Panel Heating / Cooling Systems.

The goal for this project is to demonstrate the viability of hydronic radiant ceiling heating and cooling in conventional residential buildings.

Hobo data loggers were used during commissioning to verify system cooling performance. Heating performance is well known in the industry. At the outdoor design temperature, 98F, the living room maintained 60F, and the western upstairs bedroom maintained 76F. This radiant heating and cooling design is viable for conventional residential buildings.

Geo-Radiant Heating / Cooling

The Strack House in Cool California features a geoexchange building integrated radiant heating / cooling system with hot water heating. The house is very comfortably heated and cooled with no furnace, no air conditioner, no forced air, no ducts and no vents. This remarkable house is a wood frame custom split level ranch style house. The building integrated heating and cooling radiant panels are behind and in contact with the flooring and the ceiling drywall, making the hardwood floors and the conventionally finished painted ceiling in fact the radiant panels.

Mechanical System

This Geo-Radiant system uses a 3 ton horizontal slinky geothermal loop. The terminal system in the house is a hydronic radiant floor and ceiling panel system integrated into the building located behind the finishes. The heat pump is a Tetco 2.5 ton reversing water to water heat pump. The georadiant system is suitable for any conventional house design. The system includes a Metlund D'mand hot water circulator which reduces energy and water waste.

Strack House Cool CA

A Hydronic Radiant Conditioning (HRC) system is not a "silver bullet". Building type, construction, climate zone and occupancy must be carefully considered to assess applicability.

• Building Type: Residential, retail and office buildings can benefit from HRC designs. Theaters, gyms and sanctuaries have high occupancy's and will require a Dedicated Outdoor Air System (DOAS) to condition fresh air and control indoor humidity.

• Construction: Talbott Radiant uses a building integrated hydronic radiant cooling and heating panel with an embedded heat source designed for light frame low rise construction. Hi-bay tilt-slab, post tensioned concrete and other construction types can also benefit from HRC designs.

• Climate Zone: A low humidity climate is ideal for HRC designs. Climates where the dew point is above 55° F during most of the the cooling season are best for HRC systems. In California, buildings in climate zones 9 - 16 can benefit from HRC designs. Other climate zones will require Dedicated Outdoor Air Systems (DOAS).

• Occupancy: Residential and medium occupancy building types can benefit from a HRC system. In high occupancy buildings fresh air is the dominant factor in the design. 

What are the major components to personal comfort?

1. 50% is radiation, the exchange of energy between surfaces.
2. 30%  is convection, the exchange of energy by transfer to moving air.
3. 20% is evaporation, the exchange of energy by vaporizing sweat.

The Comfort Equation: 0.5Radiant + 0.3Convection + 0.2Evaporation = Satisfied

Physical activity makes a difference, and is illustrated as a Met or one's metabolic rate.

Air comfort is illustrated by psychometric chart, shown at the right. It describes the parameters of the air which are needed  for seated comfort. Most people are comfortable at rest at 74°F at 50% Humidity in still air. The lower limit for Winter is 68°F, and the upper limit for Summer is 80°F.

We do know that psychometric chart above illustrates the parameters for half of the comfort equation, the other half is the radiant temperature of the surrounding surfaces, as illustrated by the "Comfort Triangle" below.

We do know from experience that a radiantly heated home is comfortable at a few degrees lower than a forced air heated home, and there is discussion in the literature that a radiantly cooled home is comfortable at a few degrees warmer than an air conditioned one.

The psychometric chart to the right illustrates the comfort zone influenced by the temperature of the surrounding surfaces. With a radiant panel system providing comfort conditioning, the lower limit for Winter is 66°F, and the upper limit for Summer is 82°F.

We can create comfortable radiant surfaces with less energy than that required for comfortable air. The capital costs to do so are higher. 

What are the methods typically used for radiant heating and cooling systems?

• Traditional radiant heating practice is to install hot water tubing systems in the floor. This is suitable for buildings in heating only climate zones.

• Radiant heating from ceilings is a less common practice and usually uses electric cables. 

• Radiant cooling is a method used in high rise buildings. It is rarely possible to meet cooling loads with radiant chilled floors, therefore chilled water tubing in ceiling panels is used.

• Less well known are roof pond passive solar heating / cooling systems. These were first developed by Harold Hay.  Dick Bourne has recently done several roof pond systems. These heating / cooling systems provide good comfort and economy, but put a lot of weight at the top of the building.

• Talbott Radiant Homes installs tubing in the ceiling behind the drywall to provide a building integrated, low mass, fast reacting, heating and cooling panel.

Do you have questions about radiant heating and cooling systems?

"Passive and Low Energy Cooling Survey" by Marc Rosenbaum, P.E. is a good overview on the subject.

 Rosenbaum has an esthetic objection to radiant panel cooling in his paper, we have addressed that issue with the systems used today. 

LBNL Resource-Efficient Building Conditioning
LBNL Hydronic Radiant Heating and Cooling