To maintain thermal performance of the Ondol system, elements of the system must be optimally designed so that the thermal performance and hot water flow can be efficiently transmitted from the Ondol system in apartment units. The purpose of this study is to propose the optimal design data and applicable design process of the Ondol system. The design process should incorporate the energy-efficient system as well as a comfortable indoor thermal environment in the early design stage.

ABSTRACT
 1. Introduction
 2. Design Process of Floor Heating System
 3. Design Process of Ondol Heating System
 4. Conclusion
 References

• Dong-Woo Cho(Building Environment Division, Korea Institute of Construction Technology)
• Ki-Hyung Yu(Building Environment Division, Korea Institute of Construction Technology)