Psychrometer chart:
Range can be changed, Mouse move point calculation;
Calculate once recycle and twice recycle air flow, summer and winter state,
process line shown in chart, press UpDown button to see process changing;
Export wmf format file, can be opened and printed by image browser software
as ACDSee, IE, smoothly zoomed.

Duct calculator:
Air and liquid duct;
Calculate duct flow resistance, environmental heat exchange, and adiabatic.
Note: outer coefficient of heat transfer usually 3~10, >10 when winds.