An Empirical Study of Thermal Transmittance through Windows with Interior Blinds
Keywords:
Heat Transfer, Glazing, U-value, R-valueAbstract
The main function of windows is to control the indoor climate along to provide appropriate ventilation i.e air circulation. The main objective is achieved by scheming the heat flow through the window from inside to outside in winter & from outside to inside in summer. Window solar gain has a strong sway on the building energy utilization and peak cooling load. Double glazed window are known to avert the entry of solar gain to inside the room. Shading systems such as Venetian blinds, louver shades, draperies etc. enhances the control of solar gain through windows. In this paper the thermal performance of a double-glazed window with adjacent commercially available blinds has been studied using LBNL research software WINDOWS 6.3 and the results so obtained are validated using a Guarded Heat Plate Apparatus. Despite the fact that this type of glazing system has already been studied for colder climatic conditions in the west, due to the unavailability of literature on local climatic conditions its use in tropical countries like India is very limited. A parametric study for climatic conditions of an Indian city, Chandigarh has been made to give an insight to the thermal performance of glazing systems with interior blinds. In this study the effect of different types of glazing systems i.e single and double glazed , pane to blind spacing (20mm and 40mm) and the climatic conditions of Chandigarh (Hot and Dry, Hot and Humid, Cold and Dry) on the Thermal transmittance (U-value) is studied.
References
2. Xian Devi Fang, A study of U- Factor of the window with a high- reflectivity venetian blind: solar energy, Vol. - 68. No 2 pp 207-14, 2000.
3. Windows and Daylighting Group, "WINDOW 6 and THERM 6 Technical Documentation," Lawrence Berkeley National Laboratory, 3 September 2013. [Online]. Available: http://windows.lbl.gov/soft
ware/window/6/TechnicalDocs.html. [Accessed 8 November 2013]. a. N. Bansal and G. Minke, Climatic zones and rural housing in india, forschungszentrum julich gmbh, zentralbibliothek, 1995.
4. Collins M.R and Harison, S.J, Calorimetric measurement of the inward flowing fraction of absorbed solar radiation in venetian blinds, ASHRARE transactions, Vol. 105(2),pp 1022-30, 1999. 5. Windows and Daylighting Group, "Windows 6.3," Lawrence Berkeley National Laboratories, 26 June 2013. Available Online: http://windows.lbl. gov/ software/window/6/. [Accessed 14 Sept. 2013]
6. http://m.accuweater.com.
7. Lake, K.L, A white paper on manufacturing and assembling on an affordable quick –to – build and sustainable mass housing solution for Indian cities, India Concept House, 2011.
8. J.L Wright and H.F Sullivan, Glazing system UValue measurement using a guarded heater plate apparatus, ASHRAE Transitions, Vol. 94,pt. 2, 1988.
9. Collins, M.R, Harrison, S.J, Oosthuizen, P.H and Naylor, Sensitivity analysis of heat transfer from an irradiated window and horizontal louvered blind assembly, ASHRAE Transitions, Vol. 108 (1),pp 503-511, 2002.
