Efficient Thermal Cycle Undergoing Adiabatic Contraction Based Work by Releasing Heat

By means of observational evidence it is shown that, among the vast amount of heat-work interactions occurring in closed process based transformations, there exists the possibility of doing a transformation characterized by doing useful mechanical work by contraction based compression, while increasing the internal energy. Such thermodynamic transformation has never been considered in processes. However, in reality closed contraction based compression process are physically possible in which net work is produced by contraction of a thermal working fluid while fulfilling the fundamental laws. Thus, the objective is therefore to analyze heat-work interaction modes in closed processes conducted by heat addition, heat extracting and net work done by the process. Therefore, this analysis focuses on the feasible thermodynamic transformations contributing to the achievement of efficient closed processes based thermal cycles. The proposed cycles are characterized by performing mechanical work both in the expansion phase due to heat addition, and in the compression phase due to heat releasing. The cycles achieved are characterized by operating with closed thermal processes in which both transformations with isochoric heat addition and isochoric heat extraction are associated with useful mechanical work at high performance. The analysis of the cycle between top working temperatures ranging from 350 to 700 K while botom temperature approaches 300 K has been carried out, corroborated by experimental validation for low temperatures, in the order of 350 degrees Kelvin through a test bench designed specifically for this task. It is also worth noting that the thermal efficiency is independent of the temperature ratio. Therefore the results indicate that for lower temperatures below 690 K, the thermal efficiency of the cycle exceeds the Carnot factor, which is an efficient means of recovering residual or low-grade heat efficiently.

The range of application of ORC power plant in power stations fed with low and medium thermal sources

The work presents the diagrams of the applied power plant solutions with a description of their operation and calculation algorithm. In the latter case, the cycle of thermodynamic transformations of the Rankine cycle presented in the T-s coordinate system was used, which reflects the subsequent transformations occurring in individual devices of the power plant, including the method of determining unit quantities characterizing their operation. The energy balance equations of the evaporator and the heater are presented, which among other things will be the basis for determining the coefficient that plays an important role in determining the range of applications of the single-circuit sub-critical power plant in the power plant/CHP plant. The coefficient ϕ was defined as the ratio of the mass stream of water flowing through the counter-current heat exchanger in which the liquid of the working medium is heated within the limits of condensation and evaporation temperatures, to the mass stream of water leaving the evaporator according to the dependence ϕ = ṁs1/ṁs. It has been assumed that a given mass stream of water ṁs at a given temperature Ts1 is heated in a heat exchanger which is the upper heat source. The calculations of the power plant for selected working fluids (R227ea, RC318, R1234ze and R1234yf) were made for different evaporation temperatures taking into account near-subcritical temperatures for selected supply water temperatures. On this basis, the figures ϕ = f(TEVAP) illustrating the application ranges of a single-circuit power plant in a power plant/CHP plant were drawn up. The analysis of the above figures became the basis for formulating final conclusions.

CORRELATIONS IN QUANTUM PHYSICS

We provide a historical perspective of how the notion of correlations has evolved within quantum physics. We begin by reviewing Shannon's information theory and its first application in quantum physics, due to Everett, in explaining the information conveyed during a quantum measurement. This naturally leads us to Lindblad's information theoretic analysis of quantum measurements and his emphasis of the difference between the classical and quantum mutual information. After briefly summarizing the quantification of entanglement using these ideas, we arrive at the concept of quantum discord, which naturally captures the boundary between entanglement and classical correlations. Finally we discuss possible links between discord, which the generation of correlations in thermodynamic transformations of coupled harmonic oscillators.