Electrochromic windows: Physical characteristics and environmental profile

We present the thermal and optical evaluation of a 40 cm×40 cm electrochromic window prototype mounted on an Insulating Glass Unit (double glazed window with a low emittance coating). The favorable optical performance of the electrochromic part combined with the excellent thermal protection of the advanced Insulating Glass Unit provides a product suitable for energy efficient applications. The environmental evaluation of the prototype was assessed by implementing the Life Cycle Assessment methodology. Energy savings up to 5608 MJ per unit can be achieved when the electrochromic device is used in cooling dominated areas and buildings with large facades. This corresponds to cooling and heating savings of 127.1 kWh/m2 glass per year and 94.3 MJ/m2 glass per year respectively. The reduction in building energy needs reaches 55.7% and the energy pay back time is only 0.8 years since the embodied energy represents only 3.3% of the energy saved during its life cycle. The net greenhouse gas emissions reduction is estimated to be 630 kg CO2 equivalent, while only 0.5 years of operation are required to compensate the lifecycle emissions. Net human toxic emissions reduction can reach 358 kg 1,4-DCB equivalent, compensating its life cycle toxic emissions already from 0.25 years of operation.

[1]  G. Leftheriotis,et al.  Structural and electrochemical properties of opaque sol–gel deposited WO3 layers , 2003 .

[2]  A. W. Czanderna,et al.  Evaluation criteria and test methods for electrochromic windows , 1990 .

[3]  Claes-Göran Granqvist,et al.  Electrochromic coatings and devices: survey of some recent advances , 2003 .

[4]  G. Leftheriotis,et al.  Effect of the tungsten oxidation states in the thermal coloration and bleaching of amorphous WO3 films , 2001 .

[5]  Spiros Papaefthimiou,et al.  Study of WO3 films with textured surfaces for improved electrochromic performance , 2001 .

[6]  Arne Roos,et al.  Annual energy window performance vs. glazing thermal emittance — the relevance of very low emittance values , 2001 .

[7]  G. Leftheriotis,et al.  The effect of water on the electrochromic properties of WO3 films prepared by vacuum and chemical methods , 2004 .

[8]  G. Leftheriotis,et al.  Influence of the substrate on the electrochromic characteristics of lithiated α-WO3 layers , 2004 .

[9]  Hans-Jürgen Dr. Klüppel,et al.  The Revision of ISO Standards 14040-3 - ISO 14040: Environmental management – Life cycle assessment – Principles and framework - ISO 14044: Environmental management – Life cycle assessment – Requirements and guidelines , 2005 .

[10]  Spiros Papaefthimiou,et al.  Study of electrochromic cells incorporating WO3, MoO3, WO3-MoO3 and V2O5 coatings , 1999 .

[11]  C. Granqvist.  "Charge Your Glasses" with Electrochromic Glazing , 2001 .

[12]  Spiros Papaefthimiou,et al.  Integrated low-emittance–electrochromic devices incorporating ZnS/Ag/ZnS coatings as transparent conductors , 2000 .

[13]  R. Sullivan,et al.  Review of electrochromic window performance factors , 1994, Other Conferences.

[14]  R. Sullivan,et al.  Energy performance analysis of prototype electrochromic windows , 1996 .

[15]  Claes G. Granqvist,et al.  Handbook of inorganic electrochromic materials , 1995 .

[16]  G. Leftheriotis,et al.  Effect of the tungsten and molybdenum oxidation states on the thermal coloration of amorphous WO3 and MoO3 films , 2001 .

[17]  K. Urbanik,et al.  Progress toward durable, cost effective electrochromic window glazings , 1999 .

[18]  Spiros Papaefthimiou,et al.  Advanced electrochromic devices based on WO3 thin films , 2001 .

[19]  G Finnveden,et al.  Life cycle assessment part 2: current impact assessment practice. , 2004, Environment international.

[20]  Spiros Papaefthimiou,et al.  Environmental assessment of electrochromic glazing production , 2005 .

[21]  D W Pennington,et al.  Life cycle assessment: Part 1: Framework, goal and scope definition, inventory analysis, and applications , 2004 .

[22]  G. Leftheriotis,et al.  Electrochromic phenomena in transition metal oxide thin films prepared by thermal evaporation , 1998 .

[23]  Spiros Papaefthimiou,et al.  Energy performance assessment of an electrochromic window , 2006 .

[24]  Spiros Papaefthimiou,et al.  Development of multilayer transparent conductive coatings , 2000 .