• 1 D steady state heat transfer notable points - 1. Heat transfer in only in given direction of temperature gradient. Other remaining directions either have infinite resistence or insulated hence, no temperature difference. 2. Rate of heat transfer at any point at any instant in the path of heat transfer is same. 3. There is no local accumulation of thermal energy at every point at each instant while heat transfer. 4. Temperature as a field variable at any instant has constant distribution throughout the region of heat transfer. That's why it is only function of space co-ordinate especially for 1 D T = T(x) or T(y) or T(z). 5. The variation of thermal conductivity with temperature or space can be possible. 6. Heat source or sink usually be constant or can be variable but their effect should not result in temperature variation with time. 7. Heat can spread over variable areas normally, but heat transfer rate is always constant at any given point. In short, being steady state is the net effect from variety of possible variations of inputs like area of transfer, thermal conductivity or heat source/sink, etc.