Bjarne W. Olesen, Ph.D., Professor - Technical University of Denmark

Alternatively to full air-conditioning heating and cooling may be done by water-based radiant heating and cooling systems, where pipes are embedded in the building structure (floors, ceilings, walls) or in the center of the concrete slabs in multi-story buildings. The present talk will discuss the possibilities and limitations of radiant surface heating and cooling systems. Differences in performance and application of surface systems compared to embedded systems are presented. Results from both dynamic computer simulations and field measurements are presented.

The paper shows that for well-designed buildings these types of system are capable of providing a comfortable indoor climate both in summer and in winter in different climatic zones. Various control concepts and corresponding energy performance are presented. To remove latent heat, these systems may be combined with an air system. This air system can, however, be scaled down with the benefit of improved comfort (noise, draught) compared to full air-conditioning. An added benefit can be reduced building height due to the elimination of suspended ceilings. Finally, surface heating and cooling systems use water at a temperature close to room temperature. This increases the possibility of using renewable energy sources and increasing the efficiency of boilers, heat pumps and refrigeration machines.