Efficiency Calculator by F.D. Drake, 1988 M.S. Thesis "Evaluating 
Cogeneration Options for a Campus Heating and Cooling Plant"
     In order to have a common basis on which to compare the thermal 
performance of various cogeneration systems, a subroutine has been written
to compute the first law, second law and the PURPA effciencies of the entire
system.  The equations for mu1 and mu2 are given below.  The PURPA efficiency 
mu p  is a measure of performance that is used to determine if a private 
business qualifies as a cogenerator under the PURPA act. It is defined as
                W elec + 1/2 Q heat
         Mu p = -------------------
                      Q fuel
     The calculations can account for various fuels, for heat supplied at
different conditions and for all power producers in a plant.

     W elec + Q heat    W elec + m (h-ho)
mu1= ---------------- = -----------------
	Q fuel          m fuel  LHV fuel

     W elec + A fl   W elec + m fl[(h-ho)-To(s-so)]
mu2= ------------- = ------------------------------
        A fuel		m fuel LHV fuel