Performance of the raised floor heating system with natural ventilation

In Korea, all residential buildings adopt floor- heating systems for indoor thermal comfort. And the ratio of multi-family houses exceeds 50%. Lately problems of noise between floors and contamination of indoor air in multi-family houses emerged as social issue, and performance standards related to noise between floors and ventilation were established in Housing Regulation. Concerning these issues, many systems have been developed. Recently developed raised floor heating system is not only capable of basic function to reduce noise between floors, but also is a multi-functional floor heating system enabling natural ventilation. The procedure of this system for natural ventilation is to import outdoor air through bottom space of the floor heating system, circulate indoor space and discharge it out of ceiling. In winter, powerless natural ventilation is possible with buoyancy effect caused by temperature difference between outdoor and indoor. And it also allows saving of energy by importing pre-heated air in bottom space of the floor heating system. To evaluate ventilation performance of this system, on-site measurement was conducted in 2 test laboratories, and the nominal air change rate was satisfied as 0.4~0.8 h-1 under the condition of outdoor temperature 5~-5, which was evaluated as highly possible to be applied as a natural ventilation system in multi-family houses.