Cogeneration Systems and the Utility Interface

In Serbia, there are about 1200 abandoned oil and gas wells, which have significant potential to produce thermal energy. Abandoned wells, depending on their location and thermal potential, can be used to produce thermal energy or electricity, or for the combined production of electricity and thermal energy. Thermal energy that is produced from abandoned wells is obtained using geothermal energy, so the electrical energy and/or thermal energy that would be obtained using such heat sources are balanced as energy obtained from renewable energy sources. The costs of equipping deep wells and applying the technology that would be used to produce thermal energy and/or electricity represent a far smaller part of the costs compared to the costs of making deep wells, so these abandoned wells represent an already existing significant material resource. The production of thermal energy from abandoned wells, which is based on pressing the working medium into the well, heating it and pushing it to the surface, is less energy intensive since the same well is used for the transfer of hot energy - through the appropriate working medium through tubing (narrow pipe) to the surface, and then the used cooled water is returned to the same well through the intermediate space. The paper presents a methodology for calculating the theoretical thermal potential of abandoned oil and gas wells, which was applied to the example of wells K-1, T-1, S-1 and M-1 located in Serbia, with a depth of 2.000 m, 2.250 m, 1.700 m and 2.102 m. It is shown that the theoretical temperature of the working fluid on the surface of the earth is in the range of 77.59 to 94.46°C.

An experimental investigation of energy production with a hybrid photovoltaic/ thermal collector system in Duhok city

The main aim of the study was to assess the environmental performance, through the application of the life cycle assessment, of a recycled paper production process focusing on the energy aspect. The production process occurred in a paper mill that produces packaging paper using paper and cardboard from source separation of municipal solid waste as raw materials. Two scenarios (S1 and S2) were defined by their energy supply sources. A cogeneration (CHP) system using natural gas for the combined production of thermal and electric energy was the source in S1. The Italian electricity grid (using the Italian country mix) and a natural gas boiler were the separate sources for electric and thermal energy, respectively, in S2. Finally, in order to evaluate the environmental effects on the results of the study about the variation in the natural gas supply source, four alternative Italian import mixes (M1, M2, M3, and M4) were defined by varying the contribution of the supplier countries. The environmental impacts were evaluated with ReCiPe 2016 (H) using both midpoint and endpoint approaches. The results showed that for both the scenarios, the energy consumption was the main cause of impacts mainly because of the natural gas contribution. The presence of the cogeneration (CHP) system generated significant environmental benefits compared with the use of energy provided by more conventional sources. The production and use of chemicals as well as the disposal of waste produced during the paper production were other environmental hotspots. The variation in the composition of the Italian import mix of natural gas, in terms of the supplier country’s contribution, had a significant influence on the results. The import of natural gas from Russia was the most impactful option. Since Russia is the country that contributes to the Italian import mix the most, in the next years, the use of natural gas in Italy could become increasingly impactful. Therefore, the replacement of natural gas with renewable sources is an urgent priority.

Optimizing biomass energy production in the southern region of Iran: A deterministic MCDM and machine learning approach in GIS

The relevance of the work is due to the implementation of the Federal law “on energy saving and energy efficiency and on amendments to certain legislative acts of the Russian Federation” and is aimed at reducing the cost of production of electric and heat energy in the Northern regions of decentralized energy of Russia. The aim of the work is iimproving the energy efficiency of thermal energy production through the modernization of coal-fired boilers, the rationale for the choice of an alternative technology to convert thermal energy into electricity in the areas of decentralized energy. Creation of the installations competing with diesel power plants on development of thermal and electric energy, increase of economic efficiency of production of energy in Northern regions of Russia. Research methods is analysis of existing technologies for the production of thermal energy in the areas of decentralized energy; Thermal, technical and economic analysis of technologies that allow to convert low potential thermal energy into electrical energy; Simulation of installation parameters based on the organic Rankine cycle using the software package Smoweb software package. Results are a comparative analysis of the existing technologies for the production of thermal energy in the areas of decentralized energy and selected the most effective option for improving energy efficiency; was made thermal and technical and economic analysis of the use of technologies that allow to convert low potential thermal energy into electrical energy for the district heating systems DHS-22 of villages Podtesovo

Suspended and abandoned wells present a considerable opportunity for renewable energy production, whether in the form of thermal, electrical, or combined energy. By utilizing existing infrastructure to harness these forms of energy, it is possible to reduce negative environmental impacts while simultaneously increasing energy efficiency and sustainability. This approach contributes to reducing dependence on fossil fuels and promotes the development of technologies based on renewable energy sources. Suspended wells offer the advantage of being immediately ready for use when needed, making them an efficient solution. In this paper, completion of suspended and abandoned wells for the production of thermal and/or electrical energy is presented.

The article emphasizes the inevitability of the formation of CO2 in the production of thermal and electric energy with the combustion of fossil fuel and analyzes the sources of carbon dioxide generation at power facilities in Kazakhstan. Technologies for the production of electrical and thermal energy with reduced generation of carbon dioxide, which are being implemented in a short time, are discussed. A possible method for quantifying the level of CO2 emissions for the conditions of Kazakhstan is shown, through the use of the specific consumption of conventional (carbon) fuels for production as a unit of thermal energy and / or electricity. A number of available and relatively cheap technological solutions are presented, which, when implemented, can significantly reduce carbon dioxide emissions. It is noted that these technologies can be implemented administratively and economically, and the formulations of the required decisions of the Government are given. For each of the proposed technologies, an assessment of possible volumes of reduction of carbon dioxide emissions is given and difficulties that may be encountered during implementation are indicated. A scheme for determining the degree of participation of a particular country in global carbonation is considered and it is shown that, depending on the method of "spreading" the total volume of emissions of a particular country, one and the same country can be both among prosperous countries and among a number of countries to which it is necessary to apply strict "carbon" taxes. It is noted that the determination of the share of a particular country in the form of emissions per unit area of the country's territory seems to be more "fair" taking into account the global nature of pollution.

This work aims to assess the effect of energy conversion (Thermal oil, Natural gas and cogeneration system) on atmospheric emission and energy consumption in ceramic tile product sector in Tunisia. Two tile manufactures were selected. The first plant has two production lines: The first line (FF1) operates with thermal oil with a lower calorific value (LHV) of 9811 cal/g and the second line (FG1) operating with natural gas has a lower calorific value (HHV) of 10,520 cal/g, ensuring a daily output of 300 tons each one. The second manufacture (SC2) operates with natural gas with the same LHV value. The thermal oil energy balance showed a specific consumption of 0.0481 toe/ton tile product for the FF1 manufacture line, 0.0198 toe/ton of tile product for the FG1 manufacture line and 0.0143 toe/ton of tile product for the SC2 manufactory. The electrical energy consumption was 0.0121 toe/ton of tile product for the FF1 line, 0.0108 toe/ton of tile product for the FG1 line and a production of energy (exergy) of 0.014 toe/ton for the SC2 production line. The specific consumption was split into 40% for dryer and 60% for tunnel kilns. The conversion allow to record a dryer reduction rate of 80% for nitrogen oxides (NOx), 56% for sulfur oxides (SOx), 56% for fluorinated compounds, 52% for chlorinated compounds and 52% for volatile organic compound. Whereas, the kiln reduction rate was 36% for nitrogen oxides, 51% for sulfur oxides, 36% for chlorinated compounds and 55% for fluorinated and 50% for volatile organic compounds (VCOs). Compared to natural gas line, the use of cogeneration system in kiln process shows a decrease of 67% for NOx emissions, 80% for SOx emissions, 89% for fluorinated compounds, 58% for chlorinated emissions and 64% for volatiles organic compounds. Compared to thermal oil, the use of cogeneration system reduces the thermal energy consumption by 70% and allowed to save 30% of electric energy by generate 20% of needed electric energy. The specific atmospheric gaseous emission level decrease from 2.066 g/kg of tile product for the thermal oil process to reach 0.43 g/kg of tile product for cogeneration process.

As part of Europe, Romania now faces increasing natural gas prices, growing dependence on fuel imports and the threat of global warming. One of the modern and long-term solutions, efficient and environmentally friendly to such issues is cogeneration of both electricity and useful heat. The paper deals with the implementation of an experimental cogeneration plant for combined electrical and thermal energy production, necessary for extracting heavy oil. Located in North West of Romania, at Suplacu de Barcau, the cogeneration plant was built with the aim of studying its efficiency in growing oil production with lower costs for the electrical and thermal energy used in oil field. The cogeneration plant was designed to meet the parameters of superheated steam injected in heavy oil field at 19 bars and 300°C, assuming lower costs than market prices. The cogeneration plant consists in two identical cogenerative lines; each line consisting of an electrical turbogenerator powered by one aero derivative ST18 Pratt&Whitney turbine engine, a Heat Recovery Steam Generator (HRSG) with afterburner and linked installations. The cogeneration plant is automatically operated using Programmable Logic Controllers – PLC, which provide 3 operating conditions: combined electrical and thermal energy production, electrical energy only and steam only. Design, installation and commissioning in 2004 were realized by National Research and Development Institute for Gas Turbines – INCDT COMOTI, providing 32,000 hours between overhauls. Operated over 55,000 hours, the 2 lines of cogeneration plant fulfil an efficiency of 85%. Experimental data of 3 years of cogeneration plant operation is also present in the paper.

Modern society consumes more and more energy. In accordance with the geographical location and climatic conditions, fuel costs both for providing the population with heat and for production in Russia are very high. Russia is considered the coldest country in the world, both in terms of the duration of the heating season, and in the proportion of the population living in regions with negative average annual temperature. Increasing the amount of municipal facilities requires an increase in the production of thermal and electric energy to ensure their functioning. Considering on current economic situation there is a necessity of huge investments to create generation capacity for energy production. Also there is a necessity to maintain these capacities during the off-season period, when the generation of thermal energy is at minimum level. When switching to combined energy generation for municipal infrastructure, it will become possible to use a more optimal scheme for converting thermal energy of gaseous fuels into thermal energy directed to heating water with the associated generation of electric energy. Thus the efficiency of system is increased and cost to provide facilities with thermal and electric energy is decreased.

Design of a combined solar photovoltaic thermal panel (PV/T) for the simultaneous generation of electrical and thermal energy was proposed in this study. The basis of the new design is a traditional solar panel with poly-Si solar cells. A flat channel with a heat transfer fluid is added to the front size of such a panel. This channel is bounded by cover glass. A non-stationary mathematical model was developed for determination of temperature regime in the PV/T panel. This model consists to the system of nonlinear ordinary differential equa-tions, which describes mutual influence of external and internal heat flows and temperatures. A Math-software was created based on the developed mathematical model. The numerical studies were conducted in in real-time mode for selected geographical location of the PV/T panel. Heat flux density from the Sun, wind speed and ambient temperature were determined based on data from open worldwide climate databases. As result of computer modeling, the typical temperature distributions in each layer of the PV/T panel during daylight hours were founded. It was determined that the heat transfer fluid moving in a transparent channel from the front side of the solar panel does not cool the solar cell. This heat transfer fluid ensures only their thermal stability at the corresponding value of the specific mass flow rate. With an increase of the specific mass flow rate of the heat transfer fluid, the growth of solar cells tem-perature is observed under unchanged environmental conditions. An the same time, the pro-posed design of the PV/T panel ensures a significant increase of the heat transfer fluid tem-perature. This makes it possible to use it in low-potential heat generation systems. This leads to an increase in the economic efficiency of solar panels, economy of occupied areas, optimi-zation of system of production, consumption and storge of thermal and electrical energy.

Combined heat and power (CHP) systems in buildings present a control challenge for their efficient use due to their simultaneous production of thermal and electrical energy. The use of thermal energy storage coupled with a CHP engine provides an interesting solution to the problem – the electrical demands of the building can be matched by the CHP engine while the resulting thermal energy can be regulated by the thermal energy store. Based on the thermal energy demands of the building the thermal store can provide extra thermal energy or absorb surplus thermal energy production. This paper presents a multi-input multi-output (MIMO) inverse dynamics based control strategy that will minimise the electrical grid utilisation of a building, while simultaneously maintaining a defined operative temperature. Electrical demands from lighting and appliances within the building are considered. In order to assess the performance of the control strategy, a European Standard validated simplified dynamic building physics model is presented that provides verified heating demands. Internal heat gains from solar radiation and internal loads are included within the model. Results indicate the effectiveness of the control strategy in minimising the electrical grid use and maximising the utilisation of the available energy over conventional heating systems.

Cogeneration is defined as the process of simultaneous production of heat and electricity, with the same installation (heat engine-electric generator group, turbine, etc.). Unlike classic Thermal Power Plants, cogeneration plants can be sized in correlation with the thermal energy requirement, which means that electricity is considered a "secondary" product. Throughout the article, taking into account the general theoretical aspects of the definition and operation of cogeneration systems, through the prism of specific energy indicators, the results obtained in the case of the implementation of a cogeneration system that uses the energy potential of gases are studied of combustion, for the production of the thermal agent for heating and preparation of hot water for consumption. of steam. From a functional point of view, at the level of a refinery, three superheated steam networks are needed, corresponding to three different pressure domains, which means that the results obtained in the study as the case may be, to refer to three distinct modes of operation of the cogeneration system. The main purpose of the operation of such a system for the combined production of electrical and thermal energy is to obtain as much energy as possible in the form of mechanical work by expanding steam in the turbines.

Combining photovoltaic (PV) and photo-thermal (PT) energy collection strategies in a single system can enhance solar energy conversion efficiencies, leading to increased economic returns and wider adoption of renewable energy sources. This study focuses on incorporating a commercial luminescent organic dye (BASF Lumogen F Red 305) into ethylene glycol to explore its potential for PVT applications. The optical and electrical characteristics of the working fluid were evaluated at different temperatures under direct solar irradiance. Pristine ethylene glycol reduced the maximum PV cell temperature by 10 °C. The inclusion of luminescent dye at various concentrations further reduced the maximum temperature, with the lowest concentration achieving a 7 °C decrease compared to pristine ethylene glycol. The highest dye concentration (0.50 wt%) resulted in a significant temperature reduction of 12 °C. While electrical conversion efficiencies decreased with increasing dye concentration, all concentrations exhibited higher fill factors compared to the bare PV cell during the 100-min illumination period. A ray-tracing model was employed to analyze the behavior of the luminescent dye and quantify transmitted energy for electricity and thermal energy production. Different concentrations showed varying energy outputs, with lower concentrations favoring electrical energy and higher concentrations favoring thermal energy. Economic assessment revealed the viability of certain concentrations for specific countries, highlighting the trade-off between thermal and electrical energy generation. These findings provide valuable insights for PVT system applications in different geographical and economic contexts.

Subject and purpose of work: The purpose of this work is to present the problem of municipal waste management, and its use for the production of electric and thermal energy. Materials and methods: The information used is derived from the CSO publication for 2015 in the scope of the data on municipal waste and electric energy per province. To establish the rankings of provinces, the method of zero unitarisation was applied, whose task is to bring various variables to the state of comparability with different titres and orders of magnitudes; and then the results derived from the two rankings were compared. Results: The rankings of provinces with respect to the state of waste management and obtaining electrical energy in Poland in 2015 were presented. These rankings are characterized by a significant degree of similarity. Conclusions: Regional differentiation in individual Polish provinces in 2015 is relatively moderate.