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192 snehashis


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192 snehashis

  1. 1. School of Energy Studies Jadavpur University IV th International Conference on Advances in Energy Research Indian Institute of Technology Bombay, Mumbai Advance Glazing System- Energy Efficiency approach for Buildings a Review Snehashis Ghoshal, Subhasis Neogi School of Energy Studies Jadavpur Unversity
  2. 2. School of Energy Studies Jadavpur University Objective  In building applications Windows and Glazing units are utilised for light transmission.  This leads to the path for heat flow through the glazing system. This path is normally poor in its thermal characteristics.  The paper reviews various type of glazing units and compares thermal characteristics of such systems. 2
  3. 3. School of Energy Studies Jadavpur University Introduction  Since last century, glazing systems have been modified from single glazed to double glazed in different forms and recently developed multilayer evacuated glazing.  In single glazed unit, significant heat gain/loss occurs.  Initially, double glazed units had air as a medium in between.  With the gradual development noble gas filled double glazed units were developed.  In recent days new concept of evacuated glazing units are slowly emerging. 3
  4. 4. School of Energy Studies Jadavpur University Glazing Techniques I. The Evacuated Glazing Technique II. Glazing System with TIM III. Electrochromic Evacuated Glazing IV. Multilayer Evacuated Glazing 4
  5. 5. School of Energy Studies Jadavpur University I. The Evacuated Glazing Technique  History: The concept of evacuated glazing was proposed by Zoller in 1913 with a patent granted in 1924.  Design Parameters: 1. In evacuated glazing, the internal cavity pressure between two glass panes is maintained at very low value (less than 0.1 Pa). 2. To protect the glazing unit from the stress caused due to atmospheric pressure, tiny support pillars (ss) are used. 3. Edge sealing by transition metal or transition alloy metal maintains the internal vacuum level. 4. Radiative heat loss in evacuated glazing units is reduced by applying low emittance coating. 5
  6. 6. School of Energy Studies Jadavpur University Schematic representation of double pane evacuated glazing (Fang et al., 2009) 6
  7. 7. School of Energy Studies Jadavpur University II. Glazing systems with TIM  TIM or transparent insulating material combines the contrasting requirements of high thermal insulation and high visible transmittance.  Aerogel is a promising material among TIMs for use in windows from energy efficiency point of view.  Aerogel can be classified as monolithic and granular. Monolithic aerogel is not popular for mass production. 7
  8. 8. School of Energy Studies Jadavpur University III. Electrochromic Evacuated Glazing  Electrochromic evacuated glazing is developed by attaching an electrochromic layer with a vacuum glazing unit. It can be switched between transparent and opaque state.  Electrochromic films have many potential applications in automotive industry or in buildings that provide shading and privacy applications.  Under all aspect, electrochromic layer should face the outdoor environment . 8
  9. 9. School of Energy Studies Jadavpur University Schematic representation of electrochromic evacuated glazing (Fang et al., 2010) 9
  10. 10. School of Energy Studies Jadavpur University IV. Multilayer Evacuated Glazing  Triple evacuated glazing consists of three glass panes with two evacuated gaps in between.  Main drawback of such systems is increased weight and cost.  The second cavity of the triple evacuated glazing unit is beneficial because the resulting surface-to-surface thermal resistance is twice as that of double pane evacuated glazing.  A tabular representation regarding thermal property of different glazing systems is given in Table 1 . 10
  11. 11. School of Energy Studies Jadavpur University Table 1 Comparison of thermal properties of different types of glazing systems. Type of glazing system Description U-value (W mˉ²¯K¹) Single Glazing One glass pane 5.79-6.3 Double Glazing Two glass panes with air filled cavity 2.78-3.24 Double Glazing Two glass panes with argon filled cavity 2.61-2.95 Double Glazing Two glass panes with argon filled cavity and having night insulation 1.5-1.99 Double Glazing Two glass panes with evacuated space in between 0.86 Double Glazing Two glass panes with monolithic aerogel in between 0.63 Double Glazing Two glass panes with granular aerogel in between 1.69 Electrochromic evacuated glazing Two glass panes forming evacuated glazing with a third pane having electrochrmic layer Slightly less than 1 Triple Evacuated glazing Three glass panes with two evacuated space in between 0.26 11
  12. 12. School of Energy Studies Jadavpur University Conclusion Extensive research work over the last decade led to different glazing fabrication techniques allowing a wider range of performance of glazing systems. This paper reviews different types of glazing systems and their performances. U-value of different glazing units have been compared. 12
  13. 13. School of Energy Studies Jadavpur University References 1) 2) 3) 4) 5) 6) 7) Chow T.T, Li Chunying and Zin Zhang (2010) Innovative solar windows for cooling demand climate, Solar Energy Materials & Solar Cells, 94(2), pp. 212220. Smith N and Issacs N (2009) A cost benefit analysis of secondary glazing as a retrofit alternative for New Zealand households, The Built & Human Environmental Review, 2(1), pp. 69-80. ASHRE Handbook Fundamentals (1993). Liu M, Wittchen K.B., Heiselberg P.V. and Winther F.V. (2013) Development of a simplified and dynamic method for double glazing façade with night insulation and validated by full-scale façade element, Energy and Buildings, 58, pp. 163-171. Eames P.C. (2008) Vacuum Glazing: Current performance and future prospects, Vacuum, 82(7), pp. 717-722. Buratti C., Moretti E. (2012) Experimental performance evaluation of aerogel glazing systems, Applied Energy, 98, pp. 430-437. Buratti C., Moretti E. (2012) Glazing systems with silica aerogel for energy savings in buildings, Applied Energy, 98, pp. 396-403. 13
  14. 14. School of Energy Studies Jadavpur University 8) Zoller F. German Patent, 1924:387655 9) Collins R.E., and Robinson S. (1991) Evacuated Glazing, Solar Energy, 47(1), pp. 27-38. 10) Collins R.E. and Simoko T.M. (1998), Current status of the science and technology of vacuum glazing, Solar Energy, 62(3), pp. 189-213. 11) Griffiths P.W., Leo M.W., Cartwright P., Eames P.C., Yianoulis P., Leftheriotis G and Norton B. (1998) Fabrication of evacuated glazing at low temperature, Solar Energy, 63(4), pp. 243-249. 12) Ng N, Collins R.E. and So L. (2005) Thermal and optical evolution of gas in vacuum glazing at low temperature, Material Science & Engineering B, 119(3) 258-264. 13) Fang Y, Hyde T., Eames P.C. and Hewitt N (2009) Theoretical and experimental analysis of vacuum pressure in a vacuum glazing after extreme thermal cycling, Solar Energy, 83(9), pp. 1723-1730. 14) Fang Y., and Eames P.C. (2006) The effect of glass coating emittance and frame rebate on heat transfer through vacuum and electrochromic vacuum glazed windows, Solar Energy Material Solar Cells, 90(16), pp. 2683-2695. 14
  15. 15. 15) Fang Y., Eames P.C., Hyde T.J. and Norton B. (2005) Complex multilateral insulating frames for windows with evacuated glazing, Solar Energy, 79, pp. 245261. 16) Fang Y., Eames P.C., Norton B., Hyde T.J., Hung Y., and Hewitt N., (2008) The thermal performance analysis of an electrochromic vacuum glazing with selected low-emittance coating, Thin Solid Films, 516(6), pp. 1074-1081. 17) ASTM C976, Standard test method for thermal performance of building assemblies by means of a calibrated hot box (1995) Annual book of ASTM Standard 1995;50:339-55. 18) Fang Y., Hyde T.J. and Hewitt N., (2010) Thermal performance of an electrochromic vacuum glazing, Energy Conversion and Management, 47(20), pp. 3602-3610. 19) Manz H., Bruner S., and Wullschleger L., (2006) Triple vacuum glazing: Heat transfer and basic mechanical design constraints, Solar Energy, 80(12), pp. 16321642. 20) Fang Y., Hyde T.J. and Hewitt N. (2010) Predicted thermal performance of triple vacuum glazing, Solar Energy, 84(12), pp. 2132-2139. 15
  16. 16. THANK YOU 16