From sidewalks to hospital entrances and helipads, these systems are becoming a more common part of a project’s mechanical infrastructure. Examine differences between ASHRAE’s old and updated classifications, then review design considerations such as heat of evaporation, heat loss to the atmosphere, and back and edge losses. Tubing, spacing strategies, and controls round out the primer.
Why was one floor’s laboratory ventilation failing to keep up, when it was even the closest floor to the rooftop fans? Some system sleuthing led two engineers to a fitting conclusion. Read more stories in May Issue 2017.