- 日本建築学会環境系論文集 (ISSN:13480685)
- vol.82, no.731, pp.31-41, 2017 (Released:2017-01-30)
In this study, we focused on the improvement of the additional thermal resistance of windows with shading devices. The measurement of the additional thermal resistance of windows with shading devices, such as blinds or roller screens was conducted for 64 cases under the identical test devices and conditions. The results were further analyzed in terms of gap in the opening, porosity of surface material, ventilation characteristics and emissivity, so as to verify the improved elements of additional thermal resistance. (1) To improve additional thermal resistance of the shading devices, the followings are the elements to consider: - Make the gaps of the shieling material smaller. - Use low emissivity material. - Make the heat resistance of the shading devices bigger. (2) Venetian blinds can have a better additional thermal resistance by adopting the high degree of shielding and air tightness. (3) Roller screens can have a better additional thermal resistance by adopting of low-emissivity screen and side rails. (4) Cellular screen has the highest thermal resistance among the shading devices, thanks to cellular structure and its air layer. The performance can be further improved by filling the gaps with side rails. The No. 50, the best performance one, achieved an additional thermal resistance of over 0.5[W/m2K]. (5) Using two layers of shading devices helps the additional thermal resistance improve. (6) Measured values are mostly consistent with calculated values by ISO 15099. However, there are some different values between the measurement and the calculation. The desirable difference between the tested and the calculated value is within 10%. The evaluation method taking into account the air permeability (airleakage) of the window with shading devices and the emissivity of shield member is regarded as the future subject to examine, because it is valuable in terms of simplifying the evaluation of the additional thermal resistance of the window with shading devices. (7) Even though the improvement of the window's additional thermal resistance by using shading devices is an effective measure, it is regarded as the future subject to examine because the dew condensation possibly appear on the glass surface.