Tadeusz GLINKA
The dynamics of a synchronous motor after turning off and on again the supply voltage
Presented are dynamic states of a synchronous motor which was working in a steady state while suddenly the supply voltage was turned off and then turned on. During the momentary power failure the excitation flux in a synchronous motor does not disappear. The motor rotates and in the armature winding the rotational voltage is induced. The exciting current in synchronous motors, due to the large electromagnetic time constant of the rotor winding (with an opened stator winding), causes an increase of the magnetic flux and the growth of the induced rotational voltage in the stator winding. With the most unfavorable circumstances the current Iu can reach the value of 21,6IN and the torque can reach the value of 8TN.
Keywords: synchronous motor, start-up, supply voltage turning on and off
Jacek JĘDRZEJEWSKI, Bolesław SZWEDO
Comparison of ionic and membrane techniques on an example of a power plant water preparation installation
Over the past few decades there has occurred a significant increase in the area of requirements concerning water preparation for all categories of users. Growing water quality requirements have motivated water preparation plants to improve existing techniques, combine various methods and search for new technologies. A comparison is made between ionic and membrane methods in environmental and technological terms. The possible scenario is that it is the membrane technique that will achieve a market advantage due to the growing ecological awareness and institutional pressure on environmental protection. One should also expect the development of hybrid installations which would combine elements of ionic and membrane techniques. Before making a decision to build a water preparation installation, the investors should consult representatives of both solutions and first of all the independent institutions, eneterprises making analyses and advisory firms which, on the basis of the carried out examinations, may propose a choice of the most favourable technologies.
Keywords: water preparation installations in power plants, membrane technology, ionic technology
Antoni LITWINOWICZ
Water and wastewater economy in a power plant – historical background and current operating problems
Water and wastewater economy installations in power plants not only directly affect the work of power units but they are also significantly connected with problems concerning environmental protection. In the Polish power industry there are basically used two types of main cooling systems – the open ones using surface waters in the process of cooling and the circulation ones. This article concentrates on circuits with cooling towers which need more operating attention. The gathered by ENERGOPOMIAR knowledge based on measurement data from commissioned and already working installations enables carrying out substantive assessments and formulation of conclusions concerning the designed and tested equipment being a part of the water and wastewater economy of a power plant. It also allows carrying on of various types of technological research and measurements or activities contributing to improvement or enhancement of the work of this equipment.
Keywords: water and wastewater economy of a power plant, operating problems
Maria KASKA, Andrzej SŁAWIŃSKI, Aneta ŚWIERCZ
Directions of scientific research development in the light of programming documents and EU initiatives
Analysed are directions of scientific research in Europe concerning Smart Cities in the light of EU documents and all the time emerging new initiatives. Subjects of this analysis were the following organizations and initiatives: Smart Cities & Communities Industrial Initiative, The European Innovation Partnership on Smart Cities and Communities (EIP-SCC), EU Framework Programme Horizon 2020, The European Energy Research Alliance (EERA), The Joint Programming Initiative (JPI) “URBAN EUROPE”, The Urban Europe Research Alliance UERA, The EU Smart Cities Information System (SCIS), The European Association of Local Authorities “Energy Cities”, The European Urban Agenda for EU, The European Urban Knowledge Network (EUKN), The Covenant of Mayors for Climate and Energy Office and some other European and world initiatives for sustainable development of scientific research concerning smart cities and communities in Europe as well as the proposed research priorities in this field. On the basis of documents elaborated by European Commission and in the framework of the above mentioned initiatives an assessment has been made of the state of progress achieved in such fields like strategy planning, integration, information and telecommunication, production and energy use, transport, construction, city infrastructure, climatic changes and ecology, healthcare and educational services, finances, management and social sciences.
Keywords: Smart Cities, scientific reasearch in Europe, EU documents
Agnieszka CELIŃSKA, Bartosz ŚWIĄTKOWSKI, Ewa MAREK, Mariola PŁAWECKA
Attrition resistance of oxygen carriers in the process of Chemical Looping Combustion
One of the available methods to reduce CO2 emission is combustion of fossile fuels in the process of the so-called Chemical Looping Combustion (CLC). It is the process that consists in combustion of solid and gaseous fuels with no direct contact of these fuels with air. A new and unique feature of the CLC process is the fact that the oxygen needed for combustion is delivered with the help of solid oxygen carriers. Carriers attrition measurement is practially carried on with the use of two methods – a typical one described in ASTM D 5757 Standard and the one developed by Particulate Solid Research, Inc. (PSRI) called the jet-cup method. The elaborated in Instytut Energetyki (patent application nr P-419807) testing stand aims to determine the impact of mechanical and temperature influences on attrition resistance of oxygen carriers applied in fluidized bed systems. The stand fully simulates conditions occurring in real fluidized bed systems and may additionally serve to investigate thermal processes such as combustion or gasification.
Keywords: fuel combustion, chemical looping combustion, attrition resistance of oxygen carriers
Łukasz BARAN, Sławomir BIELECKI, Tadeusz SKOCZKOWSKI, Arkadiusz WĘGLARZ
Auction quo vadis for renewable energy sources
Achieving 15% share of energy from renewable sources (RES) in the gross consumed energy balance is one of the most important and strategic targets of our national energy and climate policy. Shown is a decline in RES heat energy production and in the use of biofuels for transportation. Attention is paid to the importance of RES electric energy market for realization of the quantitative target. Discussed are basic legal acts concerning regulation of RES electric energy auctions functioning as the main mechanism supporting this type of production. Carried out is the preliminary analysis of RES electric energy auctions results in the years 2016 and 2017. Pointed out is a significant and growing threat for realization of the quantitative target for Poland. Indicated are advantages and disadvantages of the auction system.
Keywords: heat energy production, renewable energy sources (RES), RES electric energy market, RES legal acts