Field Measurements of Thermal Comfort Conditions in Buildings with Radiant Surface Cooling Systems

The performance of radiant heating systems (floor heating, ceiling panels) is relatively well documented. Water based systems, where pipes are embedded in the building structure, are now being increasingly used for cooling purposes. Several theoretical studies based on the use of computer simulations have been published, but very little is reported on the actual performance in existing buildings. There are still uncertainties on how such systems operate and on how well the space temperatures under varying external and internal load is kept within the comfort range. To study this aspect, field measurements of thermal comfort conditions were made in several buildings with radiant surface cooling systems. The systems comprise floor cooling, wall cooling and cooling with pipes embedded in the concrete slabs between each floor in a multi storey building. Long term measurements of operative, air, surface, system and external temperatures have been carried out. The analysis of the data shows that, for the major part of the time of occupancy, the operative temperature is inside the comfort range. The analysis has been lead for different classes of comfort according to existing standards. The data show an increase in space temperature during the day, which is counterbalanced by a corresponding decrease during the night. This study shows that hydronic radiant cooling systems in many buildings are an interesting alternative to full air conditioning systems, for obtaining acceptable indoor thermal environments during summer.