Selecting perimeter zone slot diffusers

[ACD1]

Seems to me that there is no consensus on this one. I'm selecting slot diffusers for an exterior zone with a large amount of glass. In addition, the ceiling height is 8'-6", with occupants sometimes directly up against the glass. ASHRAE (I think it's in "Systems and Equipment") says to select with 150fpm halfway down the way or 5 feet AFF, whichever is lower. I've seen the Price webinar:

https://www.priceindustries.com/resources?Category=Webinars

"Fundamentals of Air Distribution Selections" that states the 1% rule and then says select for 50fpm 2/3 of the way down the window. There's a big difference between these two methods! After applying the 1% rule, thinking about what the maximum possible (at design conditions, no less) 85 degree airflow is going to be in heating, and all the rest - I realize that in heating, unless the box is in maximum heating, my cfm for most of these slots will be in the "not recommended" selection area. However, in cooling - they have the potential to easily throw 50 fpm beyond the floor. Other people select solely based upon NC. If there's anyone out there that has had these problems and has personal knowledge of how to select in this situation, I'd appreciate it.

 

[EnergyProfessional]

Sounds like you talk about heating performance and you have large glass area. Depending on yoru climate zone, you will need perimeter heat (baseboard, in-floor etc.). It is impossible to "throw" enough warm air down. jsut ask all the hot-ballon captains.

Even if you can generate enough air-flow, don't you think 150 fpm would create discomfort?

 

[GT-EGR]

If your heating and cooling air flows are drastically different, you could utilize fan powered boxes so that a constant airflow is always delivered overall, just the cooling airflow is increased/decreased and the fan pulls the remaining needed air from the plenum