Hydronic radiant building surfaces for space heating

Selecting heating and cooling systems is a decision that affects both energyperformance and thermal comfort in buildings. Lately, though, energy efficiency inbuildings is strongly related with the increasing need to utilise renewable energy sourceseither solar thermal energy or wind and solar generated electricity for heating or coolingapplications. For that effort to become feasible and practical a different approach in theperception of heat emission indoors, thermal comfort, energy efficiency and thermalenergy storage is required. Hydronic radiant building surfaces provide that differentapproach since they achieve thermal comfort by heating directly the building and thepeople and not the indoor air and in addition, they utilise low temperature heating waterthat increases the efficiency of solar thermal collectors and electricity driven air to waterheat pumps while they present the feature of thermal energy storage embedded in theirconstruction. Thus, by using such equipment a totally different view on the building as asystem is possible where the building elements themselves act as heat emitters andthermal energy storage facilities. In this chapter, after an introduction to the main featuresof radiant heating systems and the perception of thermal comfort, several hydronicradiant building surfaces (floors, walls and ceilings) are compared with commonconvective heat emitters using as criteria the energy consumption and thermal comfortachieved.