Rankine Cycle Efficiency under Maximum Power Generation Condition as Applied to Low-Temperature Power Plant Using a Cryoproduct as the Working Substance

The “carnotized” Rankine cycle efficiency is studied under conditions of maximum power generation in a low-temperature power plant using a cryoproduct as the working substance. A method is proposed for evaluating the thermodynamic efficiency of the cycles that make efficient use of cold energy. A generalized thermal efficiency equation, η tN = 1 − ( T C / T h ) m , is derived for low-temperature cycles, which can be used to increase the accuracy of determination of the efficiency and the amount of additional power generation by 20–40 %. The amount of power generated in the low-temperature power plant is estimated based on the criterion of maximum performance. This method of calculation of the characteristics of low-temperature cycles is applicable for any energy generating systems. It is shown that utilization of cold energy of a cryogenic fuel (liquefied natural gas) is a promising direction of development of the idea of cogeneration and trigeneration in power plants.