Note on thermal heating efficiency

E. T. Jaynes
2003 American Journal of Physics  
Kelvin showed the maximum e ciency with which heat can be converted into work; but there is a dual theorem about the maximum e ciency with which heat at one temperature can be converted into heat at another temperature. It has some surprising implications, in particular that the e ciency with which w e heat our buildings could in principle be improved by a large factor. This long known but still little known fact is of current pedagogical interest and practical importance.
doi:10.1119/1.1508446 fatcat:b4ncl7igkjg4pivdapchqg5qwi