The pattern of flow in the inner and outer streams of a liquid or gas in regions of a sharp path bending at a right angle is considered. It is shown that a high hydraulic drag makes it energetically favorable for the fluid to perform a twisted helical motion. Such a regime is spontaneously established under real conditions. An example of this hydraulic factor is offered by an atmospheric cyclone.

The article describes a method of integrating small distributed generation components in the power system of the Republic of Vietnam. The features of the energy system of Vietnam and the technologies used for mini thermal power plants are considered. The classification of small distributed generation components is presented with implantation of the most used resources of Vietnam—fossil and renewable. A generalized methodology for selection and calculation of technological schemes for mini thermal power plants is considered. The schemes of steam-turbine mini thermal power plants operating with coal and gas-turbine mini thermal power plants with solar air heaters are selected. Based on the calculation of the selected mini thermal power plant schemes, their distribution in the territory of the Republic of Vietnam has been obtained. The thermoeconomic efficiency has been chosen as the criterion for the best option for placing mini thermal power plants; its value for the proposed option is of 6.77%.

The applicability of small coal-fired power plants as an independent and reliable power supply source was considered. The advantages of using small thermal power plants were given, and the classification characteristics of small coal-fired power plants were put forward. The exergy method was chosen as a versatility indicator for the operating efficiency of a flowsheet in question. The exergy efficiency factor of the flowsheet was 32%. With the manufacture of by-products, such as activated carbons, the exergy efficiency of the flowsheet increased to 35%. The studies undertaken substantiated the wide applicability of small coal-fired power plants for the development of decentralized power supply.