A piston-cylinder assembly containing water, initially a liquid at 50 ?F, undergoes a process at a constant pressure of 20 lbf/in2
to a final state where the water is a vapor at
300 ?F. Kinetic and potential energy affects are negligible. Determine the work and heat
transfer, in Btu/lb, for each of three parts of the overall process
(a) From the initial liquid state to saturated liquid state,
(b) From saturated liquid to saturated vapor and
(c) From saturated vapor to final vapor state, all at 20 lbf/in2

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