An irreversible Carnot cycle engine operating as a closed system is modeled using the Direct Method and the First Law of Thermodynamics for processes with Finite Speed. Several models considering the effect on the engine performance of external and internal irreversibilities expressed as a function of the piston speed are presented. External irreversibilities are due to heat transfer at temperature gradient between the cycle and heat reservoirs, while internal ones are represented by pressure losses due to the finite speed of the piston and friction. Moreover, a method for optimizing the temperature of the cycle fluid with respect to the temperature of source and sink and the piston speed is provided. The optimization results predict distinct maximums for the thermal efficiency and power output, as well as different behavior of the entropy generation per cycle and per time. The results obtained in this optimization, which is based on piston speed, and the Curzon–Ahlborn optimization, which is based on time duration, are compared and are found to differ significantly. Correction have been proposed in order to include internal irreversibility in the externally irreversible Carnot cycle from Curzon–Ahlborn optimization, which would be equivalent to a unification attempt of the two optimization analyses.

The paper presents studies based on measurements of the Fundamental State Parameters (FH, FL, Rf and N, the quantum interaction number between the Heart and the Lungs) of the Cardio-Pulmonary System by persons belonging to a family, based on established protocols, for a more complete knowledge of its functioning. Thus, the persons are different in terms of age, sex and physical characteristics (weight, height, and lifestyle), they have parental or cohabiting statuses (mother-son, father-son, husband-wife). They perform the same activities or have different concerns with a higher or lower Power consumption. The diagrams constructed using the Fundamental State Parameters in Quantum Biological Thermodynamics with Finite Speed (QBTFS) allow the study of Stationary Quantum States and the interaction Processes between them (with or without Quantum Jump), which provides very important data on the functional characteristics of the Cardio-Pulmonary System for each person. The information obtained within QBTFS of the Cardio-Pulmonary System is particularly useful for the personalized design of the Hearts and artificial Lungs according to the physical and physiological particularities of different patients.

The paper presents the results of the recent studies and research conducted within the Quantum Biological Thermodynamics with Finite Speed on the calculation and interpretation of the Cardio-Pulmonary System performance. Thus, based on the new PV/Px diagram developed for the Cardio-Respiratory System, an original Scheme for calculating the Mechanical Work and Power of the Heart/Lungs has been developed. The new Calculation Scheme allows to study the variation of the Heart and Lungs parameters for each person, in Quantum States and in Processes with and without Quantum Jump. Based on the values calculated in each Stationary State, for the cases studied, the diagrams of the Mechanical Work, of the total Power and the Entropy Source for the Cardio-Pulmonary System, as functions of the Frequencies of the Heart (F-H), and the Lungs (F-L), the maximum systolic pressure and body mass of the person were thus constructed. The study and interpretation of these diagrams - which are novel elements - provides information on interactions within the Cardio-Pulmonary System or between it and the entire body, particularly useful in bioengineering for optimized and personalized design of artificial organs.

The paper presents the Fundamental Concepts, Equations and Diagrams in a new domain which is the extension of Thermodynamics with Finite Speed (TFS), invented and called by us: Quantum Biological Thermodynamics with Finite Speed of the Cardio-Pulmonary System (QBTFSCPS). The new concepts are: Stationary States, parameters of Stationary States, Processes between Stationary States with or without Quantum Jump, Non-Stationary States. Essential parameters of the Stationary States are: Frequency of Heart Oscillations F-H, Frequency of Lungs Oscillations F-L and Quantum Number N - which characterize the Synergetic (ordered) Interaction between Heart and Lungs, in a Stationary State. We present also a Fundamental Equation discovered by us, based on experimental data, which describes any Stationary States and 4 Equations of the Processes between these States in the Cardio-Pulmonary System. Based on these new concepts and new equations we invented 6 Diagrams which describe graphically in synoptic images the Stationary States and Processes between them with or (W)ithout Quantum Jump, between Quantum levels represented by the Quantum Number N (an integer number = 0, 1, 2, 3, 4, 5, 6, ... etc.).

The successful development, applications and validation of Thermodynamics with Finite Speed (TFS) for Thermal Machines (TM) has prompted us to try to extend it to Biological Systems. As the most important Validation of TFS was achieved for Stirling Machines where basically two pistons are in continuous motion, the Cardio-Pulmonary System appeared as an appropriate candidate for study. It can be seen as an ensemble of two biological machines: a liquid pump with valves (the Heart) and an air compressor (the Lung), similarly to a two pistons machine (as in Stirling one). This association allowed us to invent a new pV/px diagram for this Biological System, similar to the one previously introduced for Stirling Machines. By using these new concepts and tools, experimental studies on more than 50 peoples (children, yang, adults, old) were done. Thousands of stationary states and processes with and without quantum jump (new concept) in the Cardio-Pulmonary System were analyzed and 5 new diagrams were invented, where this system can now be described qualitatively and quantitatively in similar way to the TFS approach. Thus, the equations of the 4 fundamental processes in the Cardio-Pulmonary System were discovered, creating what we call Quantum Biological Thermodynamics with Finite Speed, as an extension of TFS from Thermal Machines to one of the most important Biological System in humans and animals.

The use of solar energy to produce mechanical or electrical energy is presently a good related to environmental concern and sustainable power production. We propose in this paper to develop a model of a Thermomechanical solar system, with a Stirling engine. The presented model is a first step in the optimization of the main functional parameters, using only thermodynamics of the system (whatever the kinematics). So we focus on optimal control of system temperatures, and physical dimensions optimal allocation. The heat exchangers model uses ε, the thermal effectiveness of the heat exchangers (HEX) and the number of heat transfer units (NTU), and allows us to show that an optimal way to allocate in heat exchangers effectiveness, the heat capacity rates at the hot and cold side of the system is possible. The sensitivity of the model to parameters variation is reported and future improvements of the work are proposed.

In this paper we present a synthesis on the epistemological process of the discovery, invention and construction of Quantum Biological Thermodynamics with Finite Speed of the Cardio –Pulmonary System (QBTFSCPS) starting from Thermodynamics with Finite Speed Applied to Thermal Machines (TFS). We present first when and how Thermodynamics with Finite Speed of Thermal Machines was invented, developed and validated, and after that we show how we extended it to a Biological – Electrochemical - Thermal Machine, namely to the Cardio-Pulmonary System, creating what we call: Quantum Biological Thermodynamics with Finite Speed of the Cardio –Pulmonary System (QBTFSCPS).

The paper presents a new computation scheme of Stirling engine performance that was elaborated in the frame of Thermodynamics with Finite Speed and the Direct Method. Based on the new expression of the First Law of Thermodynamics for Irreversible Processes with Finite Speed that is integrated on each process of the cycle, a completely analytical model of the Stirling engine cycle is developed. It takes into account the effect of irreversibilities dues to pressure losses and imperfect regeneration on the engine performance, namely power and efficiency. The model considered three types of pressure losses occurring in the four processes of the Stirling engine cycle, dues to (1) finite speed of the piston, (2) mechanical friction, and (3) throttling of the gas flowing through the regenerator. Their effect was successively emphasized on each process and then simultaneously on the cycle. This new scheme yielded accurate results when compared with actual experimental data of two operational Stirling engines with best performance.