The need for efficiency improvement in energy conversion systems leads to a stricter functional integration among system components. This results in structures of increasing complexity, the high performance of which are often difficult to be understood easily, being in general an optimal compromise between maximization of local thermodynamic “benefits” at the lower possible expense. To make the comprehension of complex structures easier, a new approach is presented in this paper, consisting in representing them as partial or total superimposition of thermodynamic cycles. Although system performance cannot in general be evaluated as sum of the performance of the separate cycles, this kind of representation and analysis can be of great help in understanding directions of development adopted in the literature for the construction of advanced systems and could support new potential directions of work. The evolution from the simple Brayton-Joule cycle to the so called “mixed” cycles, in which heat at turbine discharge is exploited using internal heat sinks only without using a separate bottoming section, is used to demonstrate the potentiality of the approach. Mixed cycles are named here "auto-combined cycles” to highlight the combination of different (gas and steam) cycles within the same system components.
Analysis of Superimposed Elementary Thermodynamic Cycles: from the Brayton-Joule to Advanced Mixed (Auto-Combined) Cycles
MANENTE, GIOVANNI
2008-01-01
Abstract
The need for efficiency improvement in energy conversion systems leads to a stricter functional integration among system components. This results in structures of increasing complexity, the high performance of which are often difficult to be understood easily, being in general an optimal compromise between maximization of local thermodynamic “benefits” at the lower possible expense. To make the comprehension of complex structures easier, a new approach is presented in this paper, consisting in representing them as partial or total superimposition of thermodynamic cycles. Although system performance cannot in general be evaluated as sum of the performance of the separate cycles, this kind of representation and analysis can be of great help in understanding directions of development adopted in the literature for the construction of advanced systems and could support new potential directions of work. The evolution from the simple Brayton-Joule cycle to the so called “mixed” cycles, in which heat at turbine discharge is exploited using internal heat sinks only without using a separate bottoming section, is used to demonstrate the potentiality of the approach. Mixed cycles are named here "auto-combined cycles” to highlight the combination of different (gas and steam) cycles within the same system components.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
