Towards a Unified Description of the Energy Behavior of Thermomechanical Systems

The behavior of the thermal components is commonly described through a set of internal parameters: isoentropic efficiencies, pressure ratios, effectiveness factors, pressure losses, temperature relations or differences, etc. The aim of this paper is to define new internal parameters for the components, the internal parameters θ (Royo, 1994), coming from the observation of the trajectory followed by the mass flows in the h-s plane. The internal parameters θ are able to describe the thermodynamic processes taking place in the components in the same way than the conventional internal parameters, but adding two important advantages: • They allow for a unified description of the internal parameters. • They are specially adequated for the characterization of thermal systems in an analytical way. From these internal parameters, very simple analytical expressions of the characteristic equations (Valero et al., 1992) or production functions for the components that usually constitute the thermal systems can be obtained.