Consider a 1m high and 2m wide solar collector that is tilted at an angle θ form the horizontal. the back side of the absorber is heavily insulated. the absorber plate and the glass cover, which are spaced 2.5 cm from each other, are maintained at temperatures of 80°c and 40°c, respectively. determine the nusselt number from the absorber plate by natural convection for θ=90

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