A Study on the Thermal Bridge Reduced Stiffeners for the Reduction of Window Overall Hear Transfer Coefficient

창문 열관류율 저감을 위한 열교 저감형 보강재 연구

  • Received : 2015.09.14
  • Accepted : 2015.11.18
  • Published : 2015.12.31


Steel stiffener is required for reinforcing the structure of the window frame made of versatile but weak PVC material. Steel stiffener however becomes a source of greater heat loss and frequently plays a role of thermal bridge due to its high thermal conductivity. To maintain thermal resistance similar to PVC frame, steel stiffener is perforated to reduce the effective heat transfer area. To compensate the structural strength of the steel stiffener which is weakened by the perforation, the thickness is increased. Increase in thickness will also increase the thermal heat resistance. Five samples which are PVC frame, PVC frame + original steel stiffener, PVC frame + 30% perforated steel stiffener, PVC frame + 50% perforated steel stiffener, PVC frame + 65% perforated steel stiffener are modeled and simulated for 2nd moment of area and thermal resistance. Therm/window version 6.3 is used for thermal analysis. The results show that among the five samples analyzed, PVC frame + 65% perforated steel stiffener best satisfies both structural strength and thermal resistance.


U-factor;Window;Thermal bridge;Stiffener;Heat transfer


  1. Cengel, Y. A., Cimbala, J. M., & Turner, R. H. (2012). Fundamentals of Thermal-Fluid Sciences, 4th ed., McGraw-Hill.
  2. Kwon, T., W. (1993). Curtain Planning and Construction, Publishing Company Sewoong.
  3. Kim, S. S., & Youn, S. K. (2014). Steel Structure Design, Publishing Company Munundang.
  4. No, S. T., & Jeong, J. W. (2011). A Study on Analysis Method of Curtain Wall Thermal Performance Comparing Simulation and Mock-up Test, Journal of the KIAEBS of Korea, Vol. 5, 1-6.
  5. Kim, J. Y., (2015). Evaluation of Probablilistic Capacities of Old Window System in Residential Buildings for Strong Winds, J, Korean Soc. Hazard Mitig. Vol. 15,
  6. Lee, Y. W., (2010). The Analysis of Wind Load On Curtain Wall Member of the Building, Journal of the Architectural Institute of Korea,
  7. Lee, J, B., (2011). Systematic Performance Assessments for the Design of High Performance Glazing, Journal of the Architectural Institute of Korea,