Air enters a diffuser with an averaged velocity of 360 m/s at a stagnation pressure and temperature of 340 kpa and 420 k and leaves at a stagnation pressure of 300 kpa with an averaged velocity of 120 m/s and a static pressure of 285 kpa. determine, (i) the static pressure and mach number of the air at inlet; (ii) the diffuser efficiency; (iii)the mach number at exit and the overall entropy increase.

Determine the time of the day and month of the year at which the peak sensible cooling load occurs for a top floor, north-eastern corner room of an office building in durban for the following conditions: floor area: 8 x 8 x 3 m east and north walls: 115 mm face brick (outside), 20 mm air space, 115 mm ordinary brick (inside) with 15 mm plaster roof construction: suspended plasterboard ceiling, 450 mm air space, 150 mm concrete, 75mm screed, waterproofing no heat transfer across other surfaces window area 3x 1,5 m high in north wall only. ordinary glass with venetian blinds. lights and occupants : from 07: 00 to 18: 00 average light density: 25 w/m2 number of occupants : 5 seated, light office work room temperature 24°c