International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This paper presents an energy analysis of a three-cylinder steam turbine from a combined cycle power plant. Observing all the cylinders from the analyzed turbine, it is found that the dominant mechanical power producer is Low Pressure Cylinder (LPC), followed by the Intermediate Pressure Cylinder (IPC), while High Pressure Cylinder (HPC) is the cylinder which produces the lowest mechanical power. Whole observed steam turbine develop 119.41 MW of useful mechanical power. Energy loss and energy efficiency of all cylinders are reverse proportional – higher energy efficiency will result with lower energy loss and vice versa. IPC is the cylinder which has the lowest energy loss (equal to 2.59 MW) and the highest energy efficiency of 93.32%. Whole observed steam turbine has energy loss equal to 23.43 MW, while its energy efficiency is equal to 83.60%, what falls in the expected range of such low power steam turbines. Steam mass flow rate through each cylinder is the main element which defines produced mechanical power and energy flows.

In this paper is performed energy evaluation of steam turbine from the solar-based combined cycle power plant which includes analysis of each cylinder and the whole turbine. Steam turbine has three cylinders – high, intermediate and low pressure cylinders (HPC, IPC and LPC). Observed turbine is interesting because it possesses steam cooling before its expansion through the last cylinder (LPC). Due to unknown steam mass flow rates through each cylinder, for the evaluation are used specific variables. The highest specific work is obtained in LPC, while the lowest specific work is obtained in IPC. The highest loss of a specific work is obtained in LPC (29.8 kJ/kg), followed by HPC (24.5 kJ/kg), while the lowest loss of a specific work is obtained for the IPC (19.5 kJ/kg). Regardless of higher loss in specific work, HPC has higher energy efficiency in comparison to IPC (95.08% in comparison to 95.02%), while the lowest energy efficiency of all cylinders has LPC (94.92%). For the whole observed steam turbine loss of a specific work is equal to 73.8 kJ/kg, while the energy efficiency of the whole turbine is 95.00%.

Efficient use of energy means meeting the necessary needs, without compromising the level of comfort and safety, effectively using energy resources that achieve a direct saving of resources and money. Effective use of energy has a direct impact on reducing energy costs in enterprises, thus increasing their competitiveness. The purpose of this report is to investigate the opportunities for energy efficiency improvement and evaluation of energy projects in industrial enterprises. The results show an increase in the production of RES from all types of power plants except HPP. Nevertheless, hydropower retains the largest share in the structure of RES production. At the same time, there is a decrease in the average cost to society of all types of RES, except for biomass. Europe faces a number of energy problems including: increasing dependence on imports, insufficient diversification, high and volatile energy prices, rising global energy demand, security risks affecting producer and transit states, increasing threats climate change, slow progress in the area of energy efficiency, challenges related to the use of an increasing share of renewable energy sources, and need of greater transparency, further integration and interconnection of energy markets.