Air-Flow Dindows - an Evaluation of Their Potential for use in Arctic and Sub-Arctic Environments

• Main Author: Lemon, Frank L.
• Format: Report
• Language: English
• Published: 1986
• Subjects: Energy Efficiency; Arctic
• Online Access: http://hdl.handle.net/11122/10346

Air-flow windows, developed in Scandinavia, are being considered for application in arctic and sub-arctic environments. Air-flow windows consist of a double or triple-glazed outer sash and a single glazed inner sash. Room air is returned to the building heating, ventilating and air-conditioning system through the window every cavity existing between the inner and outer sashes, thus warming the inner pane of glass. Air-flow windows have the potential of improving room comfort and reducint building heat losses, particularly if the outdoor air requirement is greater than or at least can be matched to the air extracted through the windows. A sample air-flow window was tested in a guarded hot box at various air flow rates at cold side temperatures ranging from -50(degrees)F to +10(degrees)F. Based on the test results, U-values were calculated for winter night time conditions. The economics of this window system are discussed. The energy balance of an air-flow window is established. Abstract - ii List of Figures - iv Acknowledgments - vii 1.0 Introduction - 1 1.1 Description of Air-Flow Windows - 1 1.2 Brief History of Air-Flow Windows - 3 1.3 Problem Statement - 4 1.4 Scope of Investigations - 4 2.0 Test Apparatus and Procedure - 6 3.0 Energy Balance of an Air-Flow Window Under Winter Night Time Conditions - 15 3.1 Effective U-Value - 17 3.2 Energy Balance of an Air-Flow Window Considering Insolation - 19 4.0 Mean Radiant Temperature - 25 5.0 Test Results and Discussion - 27 5.1 U-Values - 27 5.2 Air Stream Temperature Drop - 31 5.3 Condensation Potential - 31 5.4 Inside Glass Surface Temperature - 37 5.5 Pressure Drop Through the Window - 39 5.6 Temperature Profile Across the Test Window - 39 5.8 Possible Experimental Error - 39 6.0 Economics of Air-Flow Windows - 48 7.0 Summary and Conclusions - 51 References - 53