b'THERMAL BRIDGING-130 (a) 60 (b) -135 55-140 AN OPTIMAL CAVITY WIDTH50) -145 SHALL BE DETERMINED BASED ON ) 22Heat Loss (Wh/m Heat Gain (Wh/m45-150 40-155 ANNUAL HEAT LOSS AND GAIN ANALYSIS35-160 IN CONSIDERATION OF WALL DESIGN AND 30-165 25-170 LOCAL CLIMATE CONDITIONS.200 50 100 150 200 0 50 100 150 200air gap width (mm) air gap width (mm)-130 (a) 60 (b) -135 55 Figure 4 (a) shows the total heat lossThe simulation results also suggest that -140 50 through walls with different cavityair cavity widths beyond 76 mm (3) widths during a typical winter daywill not result in additional heat loss, ) -145 ) 2 45 in Vancouver (January 18th, 2012)while they will have negligible addi-2Heat Loss (Wh/m Heat Gain (Wh/mobtained from CFD simulations.tional heat gain reduction benefits. In -150 40 Similarly, the total heat gains throughgeneral, an optimal cavity width shall be -155 35 the walls during a typical summer daydetermined based on annual heat loss in Vancouver (August 17th, 2012)and gain analysis in consideration of -160 30 are presented in Figure 4 (b). As wewall design and local climate condi-can observe from the figures, as cavitytions. For the cases presented here, a -165 25 width increases, the wall heat loss2 air gap is considered optimalfrom -170 20 during winter increases while the heatan energy-saving perspectiveas it has 0 50 100 150 200 0 50 100 150 200 gain through the wall decreases in thethe potential to contribute to passive air gap width (mm) air gap width (mm) summer. For example, when the aircooling of the building. Consideration FIGURE 4: THE IMPACT OF VARYING THE AIRcavity increases from 12.7 mm (1/2)of cavity ventilation for heat gain reduc-CAVITY WIDTH ON (A) WINTER HEAT LOSS AND (B)to 50.8 mm (2), the wall heat losstion can be important, especially for SUMMER HEAT GAIN. CONSIDERED AIR CAVITYincreases by 1.94 per cent, while thebuildings where overheating is expected WIDTH: 1/2, , 1, 2, 3, 5 AND 8. heat gain reduces by 28.5 per cent. to be a major issue.MARKETPLACETo participate in the BCBEC Elements Marketplace, please contact MediaEdge Publishing at 1-866-201-3096(604) 200-7861info@srengineeringltd.comSTATEMENTS IN STEEL www.srengineeringltd.comDavid Forsey 20130 - 107th Ave. N.W.David Forsey,CTRARCHITECTURAL REPRESENTATIVE Edmonton ABT5S 1W9ARCHITECTURAL REPRESENTATIVEP. (800) 661-2826C.(780) 720-6482(800) 661-2826 F. (800) 661-1852david.forsey@westmansteel.cawestmansteel.com david.forsey@westmansteel.cawestmansteel.comDavid Forsey T 800.661.2826 M 780.720.6482LANGLEY, BC | AIRDRIE/EDMONTON, ABArchitectural F 800.661.1852 E david.forsey@westmansteel.caRepresentative Toll Free: 1.888.315.1035SWIFT CURRENT/REGINA/SASKATOON, SK R7A 7B3 Your Trusted Building Envelope Consultants927 Douglas St. Brandon, MBBRANDON/WINNIPEG, MB | CAMBRIDGE, ON20 BCBEC ELEMENTSA BCBEC PUBLICATION'