Grzegorz BŁAJSZCZAK
Energy efficiency a review of regulation and standards
The concept of energy efficiency means how much energy is needed to obtain certain result. It become so important that the European Union has issued a directive on energy end-use efficiency and imposed obligation on member countries. This paper describe the European Directive, the Polish Directive and associated with it normative acts and also European Standards (valid in all member states). The new regulation not only encourage a better use of energy but they create a duty of obtaining higher energy efficiency. Not complain with this duty will lead to financial penalty.
Keywords: energy efficiency, standards, law regulations
Stefan POSTRZEDNIK
Analysis of co-combustion effectiveness - basic parameters and process conditions
Co-combustion of classical and alternative fuels is usually understood as combined combustion of solid fuels and biomass and also of liqid fuels in mixtures with liquid biofuels. Quality of the above mentioned fuels and their combustion efficiency varies, what finally influences the efficiency of power installations where the combustion process has its place. Determined are basic parameters and realization conditions of the co-combustion process. Presented are the process efficiency general analysis results and indicated are two main ranges of concern: co-combustion and thermal utilization.
Keywords: co-combustion, alternative fuels, energy efficiency, thermal utilization
Stefan GIERLOTKA
DC current electric shock of a human body and its effects
The effects of an electric shock to human body caused by DC current are different from the ones caused by AC. It is also worth saying that DC current electric shocks occur more rarely than the AC ones that is caused by a lower number of the commonly used DC current devices. Direct current means current free from ripples and in which periodic component constitutes not more than 15% of the constant one.
Keywords: DC current electric shocks, electric shock effects
Waldemar SKOMUDEK, Marek SZROT
Assessment of technical condition of high voltage studs type insulators of power transformers
The equipment used for transmission and distribution of electricity one of the elements responsible for their durability and reliability is isolation. Depending on the type of plant and requirements posed in the field of dielectric strength of insulation systems distinguish simple - such as line insulators, insulation composite systems consisting of many insulators, as well as insulating structural systems that are used to carry out the work wire by the grounded barrier. This group includes supports and bushings insulators. The paper is the first of two publications that describe some aspects of operation of power transformer bushings.
Keywords: transformers, bushings, technical condition assessment
Bolesław FORMANEK, Krzysztof SZYMAŃSKI, Adam HERNAS, Bożena SZCZUCKA-LASOTA
Erosion and corrosion protective thermally sprayed coatings for the energy boilers
Presented are problems connected with forming protective coatings by using thermal spraying techniques with the aim to protect elements of power boilers. Described are basic wear mechanisms occurring in fluidized bed power boilers, characterized are basic methods of thermal spraying allowing to make coatings of assigned structure and chemical and phase composition as well as of functional utility properties. Discussed are basic groups of thermal spray coatings highly resistant to erosion and corrosion wearing that can be applied in power industry.
Keywords: fluidized bed power boilers, erosion and corrosion resistant coatings, power boilers elements protection
Grzegorz GOLAŃSKI, Stanisław MROZIŃSKI
Low-cycle fatigue life of GX12CrMoVNbN9 -1 cast steel
The paper presents the results of research on the fatigue life within the scope of small amount of stress cycles of high-chromium martensitic GX12CrMoVNbN9-1 (GP91) cast steel. The tests were carried out at two temperatures: room one and 600oC, with the amplitude strain ranging from 0.25 ÷ 0.60%. At both temperatures there was the occurrence of cyclic weakening of the examined cast steel observed, revealing no clear period of stabilization. Moreover, the influence of temperature on the fatigue life has been noted, and it proved to depend on the level of strain and to be the biggest for the lowest levels of strain realized within the research.
Keywords: high-chromium cast steel, fatigue life, low-cycle range
Stanisław GUMUŁA, Agnieszka WOŹNIAK
Selection of geometric parameters and motion parameters of a wind power plant
The starting assumption in the planning of the construction of a wind turbine is typically the size of the production of energy in one year. The size of the energy produced is determined by several factors. The primary factor is the local kinetic energy of wind resources, then design parameters of power plants and sculpture and land use. The same amount of energy produced can be achieved with different combinations of these factors, but the cost of investment, and thus the cost per unit of energy produced can vary. The paper shows how these factors influence the choice of the size and cost of energy produced and how the optimal solution can be sought from an economic point of view.
Keywords: wind power plants, construction planning, selection of parameters
Mirosław ŁOMOZIK
Investigation of phase transformations in new generation steels for power industry in welding thermal cycle conditions
The paper presents differences in the character of the course of a thermal cycle in welding conditions compared with the cycle of a traditional heat treatment. The author elaborates the methodology of testing austenite phase transformations in steels affected by welding thermal cycles; the said methodology has been developed and put in practice at Instytut Spawalnictwa in Gliwice. The results of related tests are presented in the form of CCT diagrams for welding conditions for the following grades of structural steels applied in power engineering sector: X10CrMoVNb9-1 (P91), X10CrWMoVNb9-2 (P92), X12CrCoWVNb12-2-2 (VM12-SHC), 7CrMoVTiB10-10 (P24) and 10CrMo9-10 (P22).
Keywords: power industry steels, welding, welding thermal cycles
Kazimierz MUTWIL, Marek CIEŚLA
Evaluation of a power block selected elements effort with the use of various calculation procedures
Presented are calculation results of stress distribution in pipeline installations with the use of a professional program destined for pipeline calculations and with an application that enables in models taking into consideration detailed geometrical features of an object. It is proved that for objects working for a long time a precise determination of a diagnostic inspection range, having in view the evaluation of material degradation level, is necessary. The required accuracy of calculations is secured by FEM programs in which the finite elements map precisely the geometry of an object.
Keywords: power blocks, stress distribution in pipelines, diagnostics of block elements
Zdzisław ŚLODERBACH
Analysis of elastic-thermoplastic stresses and strains in thick-walled pressure pipe. Part I. Derivation of Basic Equations and Expressions
In this study the influence of thermomechanical coupling effect - the effect of thermal expansion due to dissipation of the energy of plastic deformation, with and without taking into account the stored energy of plastic deformation (SEPD) for the distribution of stresses, strains, temperature, the applied pressure and the residual stresses is examined. The residual stresses remain in a thick-walled tube (a cylindrical thick-walled tank) after removing the internal pressure in the process of purely elastic unloading. The obtained results are presented in the form of appropriate equations and expressions
Keywords: thick-walled pressure pipe, elastic thermoplastic stresses, thermomechanical coupling