Ducting for Heat Exchangers

[vex]

Update: Don't do this arrangement. The dimensions of the opening reduce the hydraulic diameter to basically nill making it insufficient for cooling. The alternative is to keep about the same area but keep the entry cross-section a much more 'balanced' square/rectangle. This keeps the hydraulic diameter and the cross-sectional area in line with the rule of thumb of about a 1/4-1/3 the size of the heat exchanger.