1, room air (ra) is at 75 fdb (dry bulb) and 50% relative humidity. the psychrometric slope (ehr) for the room load is 5000 btu/lbm. the total load on the room is 20 usrt. the supply air (sa) is at 55 fdb. mark the ra and sa states on the psychrometric chart with a point in a circle o and the identifying initials "ra" or "sa", and find: (a) the mass flow of the sa (b) the sa dry bulb temperature using steam table data, calculate the ra humidity ratio w = using ideal gas formula, calculate the ra enthalpy- lbm/hr fdb additional calculations: