Kalina Cycle The Kalina Cycle® is a variation of the more conventional closed-cycle OTEC system incorporating aqueous ammonia (ammonia/water mixture) as the working fluid instead of the conventional ammonia or propylene working fluid employed in earlier designs of closed-cycle OTEC power systems. The Kalina Cycle® is a break-through technology for OTEC power systems providing a nearly 80% increase in efficiency over previous closed-cycle designs. Because the ammonia/water concentrations can be varied throughout the system to optimize according to system temperatures (sort of a "designer" working fluid) and by adding an extra component – the recuperator, heat losses generally experienced in other closed-cycle designs can be minimized and recovered, thereby improving the overall efficiency of the power cycle.