One of possible directions for the use of low potential heat for generating electricity is considered. The possibility of using pentafluoropropane (R245fa) in the axial multistage turbine to drive an electric generator is analyzed. The influence of the initial pressure of the working fluid on the efficiency of its expansion is determined. The characteristics of thermal calculation of the axial turbine and restrictions for the achievement of ultimate unit powers when operating at R245fa are given.

Any analysis and optimization of complex technical systems based on the methods of classical thermodynamics are associated with certain difficulties. They are explained by the fact that thermodynamic analysis operates in terms of «energy costs» and «energy losses», while for a full assessment, it is necessary to take into account all types of costs. Consequently, any analysis and optimization must take into account economic cost calculations and ultimately lead to savings in natural resources and human labour. In many cases, the term «energy «is replaced by the term «exergy». The main task of the analysis in terms of exergy is to study the degree of perfection of processes. However, only the exergy method is not able to give results that are fundamentally different from the classical thermodynamic. The method of solving the optimization problem is based on the use of exergoeconomical method, which allows to establish the interaction of thermodynamic and cost parameters and to take the cost of the unit of exergy in the energy conversion processes as the main indicator. The formulation of the problem of optimization of complex energy systems «combined cycle gas turbine unit - lithium bromide absorption chiller» as a single energy unit is described.

The changes of the muscular tissue microstructure taking place during several freezingthawing alternation of pork, taken as an example, were studied. The dynamics of ice crystal formation and their intramuscular localization is shown. The intensity of destructive changes of a frozen meat muscular tissue at one and double freezing is described as well. The changes of pork salable condition, meat moistureretaining power as well as water activity after several cycles of pork freezing and thawing were analyzed. The meat freezing at -18 and -35 оC was compared.

This article describes the analysis of necessity developing life support systems and their application in the XXI century. The main problem concerns the use of natural resources, especially nonrenewable, and the negative impact of human civilization on the environment. The first part discusses the concept of a universal thermodynamic unit useful, suitable for transformation of energy (exergy). It is shown that this concept allows us to solve two fundamental problems. The first task - “the task of Vernadsky’s” - is an objective assessment of all natural material and energy resources of the Earth by means of universal units, the second affects the calculation of the thermodynamic efficiency of existing life support systems and, consequently, the main possibilities and limitations of development in this direction. In addition, the presented qualitative and quantitative analysis of the energy, entropy and exergic balances of the Earth with respect to the possibilities and limitations of using energy and material potentials of the planet in various life support systems.