Economic Analysis, by F.D. Drake, 1988
     This subroutine was written to facilitate the computation of the life 
cycle costs for a base case, the alternative and the difference between the two 
for a heating and cooling plant.  This routine takes into account the discount 
rate, the number of interest periods, the annual operational costs (for fuel,
electricity, etc.), as well as demand and price increases. The routine assumes
that all capital investments are made at the beginning of the analysis period.
     This subroutine will also calculate the rate of return on an investment.  
In this technique the capital investment, the operational costs and the length 
of the analysis period is known.  The objective is to obtain the interest rate 
which would yield the same benefits on the capital investment as those from the
expenditure on the system improvements.

"Evaluating Cogenertation Options for a Campus Heating and Cooling Plant"
Drake F.D.  M.S. Thesis, 1988