Asteam pipe 8m long has an external diameter of 100mm and it is covered by lagging 50mm thick. the pipe contains steam at 198°c and the temperature of the atmosphere surrounding the pipe is 18 c. the thermal conductivity of the lagging is 0.15w/mk. the surface heat transfer coefficient is 10w/m2k. assuming the pipe has the same uniform temperature as the steam, calculate the heat loss and the surface temperature of the lagging.

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