airflow an opposing cambered surface may be positioned a short distance adjacent to the said coanda surface to act as a guide for said secondary airflow the opposing surfaces converge near their mid plane normal to the chord of the cambered surfaces and diverge at both the inlet and outlet of secondary flow thereby funneling ambient air into the area of convergence and causing an area of low pressure at the discharge thereby drawing additional ambient air into the secondary airflow in the present invention a unique coanda flow reversing is provided by a section of the cambered surface that may be repositioned so as to close the slotted opening through which said wall jet is generated and to open a second slotted opening in the opposing direction causing a reversal of the wall jet and secondary airflow this allows of overall airflow from the fan to be directed from ceiling to floor in the cooling season and floor to ceiling in the heating season according to a further optional aspect of the invention filtration means may be either or both mechanical or electrostatic according to a further optional aspect of the invention primary air airflow discharged by an impeller is pressurized within a plenum chamber and is further discharged at high velocity through an opening coincident with a cambered surface such as to cause consistent fluid wall attachment of said discharged air said fluid wall attachment is well known to the art as the coanda effect said cambered surface is known as.