- What's the promise of radiant cooling?
- Why all the fuss?
- What's the big deal?
- Why has it taken so long to develop?
- Why is it feasible now?
The promise of radiant cooling is to be able to bring the comfort and economy of radiant heating to cooling buildings in the summer.
The fuss about radiant cooling is "mold". Radiant cooling begins to fail when water condenses on the radiant cooling surface. This is bad. Radiant designs must avoid radiant surface moisture. Dehumidification is necessary in many climate zones for comfort, and to prevent mold growth. Architects, engineers and contractors will design their projects to provide fresh air and dehumidification necessary for healthy buildings. Radiant cooling provides "sensible" cooling. Dedicated Outdoor Air Systems (DOAS) provide cool, dehumidified fresh air.
The big deal with radiant cooling is it takes much less energy to comfort condition a building than a forced air cooling system. The National Renewable Energy Lab (NREL) has compared forced air and radiant systems energy demands and conclude that radiant cooling systems in many cases can reduce building cooling energy by about half.
Building construction standards have improved dramatically in the last half century. Building envelopes, the insulation and windows are much better. The result is that the energy requirement to cool buildings is much less than in the past. Radiant cooling has a limited capacity based on the difference between the comfort design and outdoor temperatures. The energy required to cool buildings is now low enough that radiant cooling is feasible.
Talbott Solar & Radiant Homes Inc. has completed eleven homes over the last six years with prototypes of the xLath radiant ceiling heat exchange modules. The Western Cooling Efficiency Center (WCEC) is beginning monitoring and testing several of these homes in 2010 so we will have a clear sense the value of radiant cooling sometime in the next year. We did some spot testing last year on two homes with radiant cooling. I'll publish the results of that test in future posts.
Talbott Solar & Radiant is training xLath radiant cooling installation the week of June 21-6 in Monterrey and Ventura. It should be fun to work with new crews installing the new ceiling modules.
ReplyDeleteWorking with a regional utility and state energy commission we're planning a new showcase house in Sacramento. It is very refreshing to discuss methods to condition the building and heat water using very simple, reliable equipment.
ReplyDeleteWe agreed to use radiant heating and cooling using Xlath radiant ceiling modules and a reversing chiller (air to water heat pump). Solar hot water will be provided by a Progressiv Tube solar water heater with electric tank backup.
The requirement for fresh air in new homes requires some ventilation. The ventilation adds a cost, and in some cases will provide a pathway for energy losses. The design provided by the engineering company utilizes 1 centrally located Energy Recovery Ventilator (ERV) and substantial duct work.
I think a better design would utilize small ERV units associated with conventionally required ventilation. If the kitchen and bathroom exhausts were connected to ERV units with fresh outdoor air distributed to the adjacent rooms, the additional costs and energy losses would be minimal.
With great design and equipment we should be able to build comfortable houses at a reasonable cost.
Hi Dean,
ReplyDeleteis possible to post some photos of this projects??
Thank you!!
S.