Informational equipment are difficult systems which performance reliability depends on a number of internal and external factors. One of the most important external factors is the quality of supplied electricity. Dependence of performance reliability of informational equipment upon the quality of supplied electricity, the impact of equipment themselves on the feeding system/net are discussed in this work. The standards of quality of electricity are overviewed, the deviations of voltage and their influence over informational equipment are evaluated. Means of increase of reliability, their structure and course of performance are described, their advantages and weaknesses are specified. Electrical ground system has major influence over reliable performance. In case of incorrect installation of the system it is possible to cause system foul-ups or even put a human life at risk. The influence of informational equipment over feeding net/system is evaluated in this work, the example of calculation of workload is presented.

The theme of Master project of Energetics engineering is actual because in nowadays it is important not only design and functionality of bicycle, but also safety and technological tests of bycicle frame, fork and other part corresponding to international standarts. In Master project was created system for dynamic changing force applying on dynamic pedal and wheel strenght tests. Results of practical pedal pushing research and computations of modelated pedaling system were similar. Analysis of pneumatic cylinder and proportional pressure regulator (using Centaurus Plus modeling program) showed that it is necessary to reduce cylinder working cell volume to enable system to repeat 3 Hz set signals. Using algorithms models was created program for data input, processing and visualizing of testing stand. This program was kindly evaluated by specialists of Technological Test center of Faculty of Technology.

The work is directed for one of alternative energy resources – renewable sources of energy. The main task is to examine potential produce biogas out of maize silage. The object of analyses was a biogas plant operated on different organic wastes in the pigs farm of UAB “Lekeciai”. The technologies of biogas production and energy input were analysed in this work. Acording to empirical equations there were developed an estimation methodology of energy consumption in biogas plant. A Energy consumption of technological equipment and energy consumption of maize silage has been investigated and determined. Energetic potential of maize silage have been investigated during experiments. Energetic efficiency of biogas plant given different composition of organic wastes has been determined. Have been estimated efficient of producing biogas out of silage maize.

Pateikto magistrantūros baigiamojo darbo tikslas – išmatuoti degimo proceso kokybę, atlikti reguliavimus. Išnagrinėti galimybę automatiškai ir optimaliai valdyti kieto kuro katilo degimo procesą. Palyginti gautus eksperimento rezultatus, vykdant degimo proceso reguliavimus. Darbe išanalizuotas medienos biomasės panaudojimo Lietuvoje potencialas. Pateiktos technologijos šiluminės energijos gamybai decentralizuotam šildyme. Pristatyti automatinio reguliavimo sistemos principai. Pateikta tyrimo metodika, rezultatai. / The aim of master thesis is – measure results burning process quality and curry out regulation. The research possibility control solid fuel boilers burning process. There is made an analysis of biomass utilizing potential in Lithuania. There is listed technology’s in heating production. Also in this work are given the rules of system automatic control. There is a listed research methodic, results.

Mažieji generatoriai nėra kokia tai naujiena elektros energetikai. Pirmiausia šie generatoriai yra pasiskirstę po visą elektros sistemą, dažniausiai yra arti tiesioginių elektros vartotojų ir yra įjungti į skirstomąjį tinklą. Antra, jie dažnai naudoja atsinaujinančiosios energijos šaltinius, pavyzdžiui vėją arba saulės šviesą. Todėl kalbant apie vėjo elektrines arba mažąsias hidroelektrines tarp atsinaujinančiosios energijos, paskirstytojo generavimo ir mažųjų generatorių sąvokų didelių skirtumų nėra. Atsinaujinančiųjų energijos šaltinių panaudojimas, globalinis gamtos atšilimas ir su tuo susijusi pasaulio visuomenės veikla yra įgijusi tarptautinių susitarimų ir planų formą. Kartu pasaulio energetikai perspėja, kad atsinaujinančios energijos šaltiniai gali pakeisti tik nedidelę tradicinės energetikos dalį. Pirminės energijos vartojimo taupymas, perdirbimo efektyvumo didinimas yra žymiai daugiau naudos atnešančios priemonės. Ateityje atsinaujinantys energijos ištekliai vis labiau įtakos energijos tiekimo įvairovę, emisijų sumažinimą ir tinkamą energijos naudojimą. Šiuo metu veikia per 20 tūkstančių vėjo elektrinių, įrengtų įvairiose pasaulio šalyse. Šiuolaikinė technologijų pažanga garantuoja šios energijos eksploatacijos patikimumą ir pelningumą. Esamų technologijų elektrinių galingumas kinta plačiose ribose: nuo kelių kilovatų iki keleto megavatų. Taigi ši technologija sudaro galimybę labai įvairiai panaudoti vėjo energiją, pvz., baterijos krovimui ar būsto apšvietimui... [toliau žr. visą tekstą] / Girgždys V. The investigation of connection of small generators to distribution network: Master thesis of electrical engineer / research advisor doc. dr. E. V. Nevardauskas; Šiauliai University, Technological Faculty, Electrical Engineering Department – Šiauliai, 2007. – 52 p. Small generators aren't the new thing for energetics. First, these generators are distributed among all electric system. Second, they often use renovated electric sources. Small generators are used in small hydro – elekctric power stations as well as in wind electric power stations. For that purpose in research there is chosen small generator which is used in wind electric power stations. At these days more than 20 000 wind electric power stations function all over the world. Contemporary progress of technology guarantees the reliability and profitableness of explotation of this energy. The aim of this research is to analyze the principles of small generators, effects and – the main demands of adopting them to the approprate places and their connection to the distributive electric wiring network.

Darbe nagrinėjama visuomeninio pastato vėsinimo sistema. Pastatas, kurio naudingas plotas 7900 m2, yra Vilniaus mieste, jo vėsinimo sistemoje yra 268 ventiliatoriniai konvektoriai. Pasirinkti trys šių įrenginių hidraulinio aprišimo variantai: pastoviojo srauto sistema, kintamojo srauto sistema su rankiniais balansavimo ventiliais ir kintamojo srauto sistema su automatiniais balansavimo ir valdymo ventiliais. Lyginamos pradinės sistemų investicijos ir montavimo bei eksploatacijos išlaidos. / An issue is a cooling systems analysis in a public building. Public building is situated in Vilnius city, area of 7900 m2, installed 268 fan coils. The comparison is made modelling between constant flow, variable flow with manual balancing, and variable flow systems with automatic balancing control valves. Analysis is done for initial investment (installation costs) and operating costs.

Calculation methods of electric power loss in 10 kV distribution network were analyzed in this study. It was examined what influence to power loss calculations has the cable resistance dependency on temperature and cable load. Voltage losses dependency on step-down transformer load, active and reactive power coefficients cosφ and sinφ was also an object of this research. It was intended to analyze comparative power loss dependences for various cross-section 10 kV cables too. Electric power loss calculations according to average load current are made for the real distribution network.

Purpose of this work is to propose and study new ways of automatic generation control (AGC) and ways for accounting of this service; formulate key methodology principles of payment for system services; estimate costs of automatic generation control.

The main objective of the Thesis is to work out the methodology aimed to develop a closely integrated electricity network model to be used for real time calculations, and afterwards, based on this methodology, to develop a model of a closely integrated electricity network, which would be applicable in real time calculations of active and reactive power.

Behavior of combustion process in the fuel bed on the grate, is characterized by different thermochemical conversion stages, each with significantly different temperatures, and the reacting conditions. This simple analysis of combustion processes taking place on the grate is a useful information for understanding of the paths of pollutants formation and destruction as well. The large fixed bed reactor was used for obtaining the experimental results of straw combustion. The fixed bed reactor contains a column of biomass fuel that is ignited at the top and with air entering through the grate from the bottom, measurements are performed while the ignition front proceeds downwards. The influence of inlet air flow velocity and temperature, moisture content in the fuel and oxygen concentration in the inlet air on combustion parameters such as ignition front velocity (kg/(m2·s)), temperature, and gas species concentration during combustion is presented based on measurements of in-bed temperatures along the bed and different gas compounds (O2, CO2, CO and NO) over the bed. A 1-D transient heterogeneous model was used for straw combustion in a fixed bed. The processes included in the model comprise: moisture evaporation, biomass pyrolysis, heterogeneous reaction of char forming CO and CO2, homogeneous reactions of CO, H2, CH4, CxHy and tar, heat and mass transfer between the gas and solid phases. The model provided detailed structure of the ignition flame front, gas species... [to full text]