  From thermodynamics point of view, in this era of aiming at energy
conservation and sustainability, we need to develop more accurate ways to
design thermal power, cooling and heat pump cycles. It has been the general
practice in thermodynamic analysis of cycles to use the Carnot efficiency and
Carnot coefficient of performance which are the highest upper bound to
efficiency and COP of cycles. In the present report through the application of
the second law of thermodynamics for irreversible processes, which results in
the general inequality relation for the entropy production, we have introduce
new upper- and lower-bounds to the efficiency of thermal power cycles and COP
of cooling and heat pump cycles. The resulting upper- and lower-bounds are
closer to the actual efficiency and COP of cycles. That allows us a more
precise design of cycles and the choice of cycles working fluids.
