For friction to occur two surfaces have to rub against one another. This is a destructive process leading to loss of the abrading parts. Now the trend being conservation of existing resources,it becomes difficult to envisage such energy source. However it is thermodynamically a possible process and could be explored. Good Luck

Dr Arun Rao

You wrote:

>For friction to occur two surfaces have to rub against one another. This is a destructive process leading to loss of the abrading parts. Now the trend being conservation of existing resources,it becomes difficult to envisage such energy source. However it is thermodynamically a possible process and could be explored.<

Of course it's a destructive process. Most thermal processes require consumption of some material.  The question is whether the 'cost' of the material versus the process efficiency make tribothermal generaltion an economical process.  The opportunity lies in the relatively simple reclamation of the material and also the higher enegy capacity of solids.  I take it form your response that you are not knowledgable of any work on the efficiency of friction [eg the input torque work of two motor-driven, counter-rotating discs vs. output heat of friction]...?

q12023,
  Why so abrasive (chuckle) with the good doctor?  He has a point about consumption, as it's not as easy to replace an abrading solid as it is to pipe in fresh fuel.  As for a practical friction energy source, you would a pre-existing and plentiful input like flowing water.  I think any purpose-built input would require more energy than you would get out (that confounded prohibition of perpetual motion).
  One elegant application of all this is regenerative braking, which is used in some of the prototype solar cars to reclaim some of the energy you waste slowing down.  Is that the sort of system you allude to, q?  If you know of other applications being attempted, I'm interested to hear about them.

There is a friction stir welding developed by NASA Glenn Research center for welding Al alloys. This precisely uses friction energy.

Sivakumar