Water enters a counter flow, double-pipe heat exchanger at 45 c, flowing at the rate of 0.5 kg/s. it is heated by oil (cp = 1.884 kj/kg. k) flowing at the rate of 1 kg/s from an inlet temperature of 105 c. for an area of 18.0 m2 and an overall heat transfer coefficient of 340w/m^2.k, determine the total heat transfer rate.

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