Allam proposed to realize problem of CO2 emissions by using supercritical CO2 cycle as working fluid with heating by carbon fuel burning in pure oxygen and then pumps CO2 into underground volumes remaining after oil production.Interest in the Allam cycle shows readiness for technological difficulties and high costs for combating CO2 accumulation in atmosphere. The formic acid cycle begins with the conversion of CO2 from the atmosphere or from flue gases to an aqueous solution and the electrochemical reduction of CO2 into formic acid. Formic acid is a convenient and safe energy storage for fuel cells, since the electrochemical process is reversible. In the reverse process (oxidation), the released CO2 can be immediately immobilized and further buried as a component of the building foam concrete. The formic acid cycle can serve as a "green" alternative to the dominant oil cycle of basic chemical production. It should be noted that even if the task of combating CO2 emissions and global warming will be no longer relevant, the value of the formic acid cycle will be preserved, since it solves a broader spectrum of tasks for the ecologization of energy generation and organic chemistry.

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Artificial roughness (AR) formed by annular rolling or dimpling is one of the most well-known examples of Reynolds analogy (RA) breaking in a favor of heat transfer. Surfaces which can be called ARPD - Artificial Roughness, are manufactured by wall Pressure Deformation. ARPD surfaces have some similar thermal hydraulic properties which permit to unite them in the common group. General characteristics of ARPD surfaces are considered here. But the main attention is paid to such surface performance for coolants with high Prandtl numbers. It is important that Reynolds numbers must be close sufficiently to its critical value for smooth tube. Some experimental data show that extremely high heat transfer enhancement ratio can be obtained under such conditions for substantially less pressure loss ratio increase. Similar qualitative results obtained for several types of ARPD — dimpled, annular rolled and spirally corrugated tubes — are demonstrated. These results are related partially with critical Reynolds number decrease and partially with specific character of heat transfer evolution in laminar–turbulent transition range for high-viscous liquids. Such enhancement method can be used effectively for heat exchangers with high-viscous liquids (oils, for example).

Energy efficiency improvement and waste heat utilization in power generation and energy intensive industrial applications are in the main focus of the researchers and engineers nowadays. A great deal of experience was gained by the industrial leaders such as ORMAT, Siemens, Caterpillar, Turboden, and others. However, the commercially and semi-commercially available systems for waste heat utilization have certain restrictions that limit the utilization cycle efficiency to approximately 18%. The paper presents an innovative concept of waste heat utilization system that allows reaching the utilization cycle efficiency up to 28–30% employing low-boiling media such as butane, propane, pentane and others. Applying such a concept to Distributed Generation systems the overall energy efficiency could be boost up to 58–60% and further up to 90% in case of CHP production.

Direct-contact heaters of feed water are especially popular as low-pressure heaters (LPH). These devices are successfully used in Russia during a long time both for conventional and nuclear power plants. Moreover, abilities of such devices to operate as deaerators led to the development deaeratorless schemes. One of most important conditions of reliable operating of such LPH is the prevention of damage of steam turbines, because of back flow of wet steam to the turbine. In this paper processes of boiling up are considered in direct contact LPH-2 which occur during stopping of turbine and its specific features concerned with dependence of sonic speed two-phase flow on vapor and liquid volumetric portions during flow enter in compensating tubes. Computer analysis showed, that the rate of generation of steam in the superheated water depends on the pressure exceptionally strong. Zone of churn flow regime, which is formed in the upper part of the condensate tank appears very sensitive instrument of flow rate control. As it is shown in such a situation, the system becomes self-governing and will not miss a steam consumption, which leads to the entrance some part of churn regime zone to pressure equalizing tubes. The calculations show that the safety can be ensure even in the conditions when backpressure valve absent. Such the conclusion is confirmed by the experience on operation direct contact LPH in Russian power plants.