Use the second law of thermodymanics to explain why energy cannot be recycled?

Question

Use the second law of thermodymanics to explain why energy cannot be recycled?

Answer 1

Well, if you want to extract work from heat, energy has to flow from hotter to colder environment - and maximum energy would have been extracted when all the heat has been transferred from hot to cold to bring the system to an equillibrium (thermally speaking - same temperature). now, recycling in traditional world means, using the energy again, which is at the ambient (or what was colder before). now, you can't really recycle as heat isn't going to want to flow back to something else if that was colder (do infite regression on this, if you do find a colder environment).