Cogeneration Energy Systems Research Articles

Review of best practices for global cogeneration policy: Benchmarking and recommendations for Malaysia

Despite the Malaysian government's efforts to promote cogeneration technology, it constitutes a mere 4.2 % of the country's total electricity generation. To address this issue, this review article aims to identify and benchmark global best practices for bolstering cogeneration implementation in Malaysia. While previous studies in this domain have centered on examining government policies within the specific regions, this paper underscores the imperative for an updated and comprehensive literature review to systematically collect and categorise best practices from around the world. This work examines the adoption of cogeneration energy systems within nations characterised by a substantial presence in their energy composition, simultaneously exploring the roles of regulatory frameworks in promoting their uptake. The scope of the literature review includes statistical data, reports, and other relevant scholarly works on cogeneration policies. Based on the findings, the review paper concludes that well-crafted policies are instrumental in encouraging rapid technology advocacy. The legislative landscape pertaining to cogeneration implementation in Malaysia is scrutinised, followed by a comparative analysis against global best practices to identify opportunities for improvement. Three crucial elements emerge as paramount to expediting the adoption: (i) administrative recognition, (ii) financial initiatives, and (iii) regulatory improvements. Several recommendations for the Malaysian cogeneration roadmap are presented. Overall, this paper offers insights into the chronological evolution of cogeneration policy development and provides actionable guidelines for developing effective policies in Malaysia and other South-East Asian countries.

Micro-scale fuel cell cogeneration system response combined with heat pump consumption in arid zones

This study aims to evaluate a new concept for Cogeneration Energy System (CES) designed to supply an area of 80 m2 located in an arid zone (Southern Algeria). A heat balance is conducted on a prototype house using real data. Numerical simulations are performed to test the heat balance with a Proton Exchange Membrane Fuel Cell PEMFC sub-system (PEMFCs). The design targets to provide both electrical and thermal energy required for the house. Simulation and energy balance allow to assess the heat transfer of the entire system for both heating and cooling operation modes. The variations in critical temperatures at the inlets and outlets of the heat storage tank, the energy transferred from the PEMFCs to the load, and the required hydrogen quantity are determined. In heating mode, the cogeneration efficiency of the PEMFCs stands at around 68.5 %, while the CES efficiency ranges between 65.8 % and 67.3 %. In cooling mode, the PEMFCs efficiency ranges from 64.5 % to 68.5 %, with CES efficiency also ranging from 64.2 to 66.2 %. Based on these findings, the CES for a home in an arid region requires a maximum power of approximately 1 kW and a hydrogen consumption of 5 kgH2.

4-E analysis and multiple objective optimizations of a novel solar-powered cogeneration energy system for the simultaneous production of electrical power and heating

Owing to its natural and rich advantages, exploration of solar energy technology has become increasingly popular in recent years to counter the growing crude oil prices. However, its universal adoption is still limited, not only due to environmental restrictions but also due to lower overall efficiency. Rankine cycle is optimised to conduct 4-E (Exergy, Energy, Economic and Ecological) analysis. Furthermore, three sets (R-113, R-11, and R-1233zd) of refrigerants are prioritised and ranked on the basis of 4-E analysis as outcomes. The contemporary study addressed all critical factors and explains the impact of solar irradiance, mass flow rate of molten salt and steam, turbine inlet pressure, and turbine inlet temperature which are eventually weighed and prioritised using combined multi-criteria decision making (MCDM) techniques. The energy efficiency, exergetic efficiency, power/ cost of electricity, and ecological emissions are taken as the indicators of the combined cycle, respectively. The energy efficiency of the hybrid system is improved to 75.07% after including cogeneration cycle, with an increment of 54.58%. In comparison to conventional thermal powerplant setups, the power/cost of electricity and ecological efficiency have been reduced by 68% and upgraded by 16%, correspondingly. Direct normal radiation is the most critical factor followed by turbine inlet temperature. Further, the result indicates that maximum exergy destruction that occurs in the central receiver declines to 39.92%, followed by heliostat and steam turbine which was 27% and 9.32% respectively. In conclusion, the hybrid cycle can furnish cheaper electricity, with lower carbon imprint in sustainable manner with better efficiency.

Green hydrogen production and utilization in a novel SOFC/GT-based zero-carbon cogeneration system: A thermodynamic evaluation

Owing to the rise in global energy demand and environmental issues caused by energy supply and distribution, the attempt to design and develop novel eco-friendly and efficient cogeneration energy systems is one of the current research focuses. In this regard, this study presents a novel zero-carbon cogeneration energy system based on a pressurized solid oxide fuel cell-gas turbine (SOFC/GT) with a carbon capture and storage (CCS) process. The designed system accomplishes the joint production of energy (electricity, cooling, and heating) and matter (hydrogen, oxygen, condensate water recovery, and carbon dioxide). The proposed system also includes an advanced alkaline electrolyzer (AAE) system, an organic Rankine cycle, a LiBr-H2O absorption refrigeration cycle, and an LNG regasification cycle. A combination of a solar concentrated photovoltaic/thermal (CPV/T) system and wind turbines feed the AAE system, resulting in green hydrogen production. According to the simulation results, the suggested system under the design conditions generates power, cooling, and domestic hot water with 315 kW, 137.5 kW, and 1.012 kg/s, respectively. Also, this system can capture and store carbon dioxide, recover condensate water, and supply natural gas to the pipeline with values of 74.88 kg/h, 137.9 kg/h, and 624.24 kg/h, respectively. The results from thermodynamic analysis indicate that the CPV/T system has the highest contribution to the exergy destruction rate, and the presented cogeneration system operates with energy and exergy efficiency of 58.09% and 38.58%, respectively. Furthermore, a comprehensive parametric study has been conducted on the developed system in which the impact of important parameters, such as SOFC operating temperature, current density, solar radiation, air velocity, etc., on the output parameters of the system has been examined.

Thermodynamic analysis of a hybrid cogeneration energy system based on compressed air energy storage with high temperature thermal energy storage and supercritical CO 2 Brayton cycle

The large-scale penetration of renewable energy leads to some imperative issues to the power grid. Energy storage technology is regarded as an effective method to solve these problems. In this paper, a hybrid cogeneration energy system based on compressed air energy storage system with high temperature thermal energy storage and supercritical CO2 Brayton cycle is proposed. A thermodynamic model of the system is established. Energy and exergy analysis are carried out based on a case study. It was found that under the design condition, the round trip efficiency of 58.66%, the energy storage density of 5.45 kWh/m3, and the overall exergy efficiency of 62.00% can be achieved. At the same time, the hot water about 88°C can be supplied. The influences of some key parameters on the performance are analyzed. It was found that the round trip efficiency is most sensitive to the outlet temperature of high temperature thermal energy storage system, isentropic efficiency of compressors and turbines, followed by the intercoolers effectiveness.

Biogas Pollution and Mineral Deposits Formed on the Elements of Landfill Gas Engines.

Municipal landfills generate a significant amount of high-energy biogas, which can be used as a renewable gaseous fuel. However, it is necessary to improve the quality of this biogas due to the presence of various chemical compounds. The most common pollutants in landfill biogas include volatile compounds of silicon, sulphur, phosphorus and chlorine. The aforementioned elements, as well as other metals, were found both in the deposits and in the engine oil. The paper presents detailed characteristics of the solid residues formed in selected parts of gas engines powered by landfill biogas. Its elemental composition and morphology were investigated in order to determine the structure and influence of these deposits. In order to better understand the observed features, selected analyses were also conducted for biogas, engine oil and the condensate generated during biogas dewatering. It was found that the content of individual elements in samples collected from the same part of the gas engine but sourced from various landfills vary. The occurrence of elements in deposits, e.g., Mg, Zn, P and Cr, depends on the location of sampling sites and the type of engine. It was also observed that the deposits formed in parts that come into contact with both biogas and engine oil contain Ca or Zn, which can be related to biogas pollutants as well as different oil additives. The presence of Al, Fe, Cu, Cr, Sn or Pb in selected motor oil samples can be explained by the penetration of metallic abrasives, which confirms the abrasive properties of the formed deposits. The analysis of the characteristic deposits may contribute to the selection of an appropriate landfill biogas purification technology, thus reducing the operating costs of energy cogeneration systems. Finally, we highlight challenges for biogas purification processes and anticipate the direction of future work.

Coordination control for Integrated Solar Combined Cycle thermoelectric coupling

Improving the utilization of solar energy and promoting the development of integrated energy systems, solar thermal power generation systems are researched and widely used. In the integrated solar combined cycle thermoelectric system, traditional power generation equipment as an auxiliary energy source mitigates fluctuations because of solar energy’s intermittent nature and uncertainty. However, because of the difference in response speed of different power generation equipment, it leads to imbalance of supply and demand power, which affects the smooth operation of the system. This paper proposes a novel coordination control method for integrated solar combined cycle thermoelectric coupling system. To solve the different energy response speed mismatches problem, an inertial power compensation scheme is proposed based on the established solar energy cogeneration system model, and the dynamic performance and robustness of the system are improved. In this paper, the intelligent optimization algorithm is used to optimize the parameters to improve the control precision of the controller. Finally, the paper carries out multi-scenario simulation with the 50MW solar thermal power generation and the 50MW gas turbine to verify the effectiveness and stability of the proposed coordination control method.

Assessment and multi-objective optimization of a vanadium-chlorine thermochemical cycle integrated with algal biomass gasification for hydrogen and power production

A cogeneration energy system for green hydrogen and power production from algal biomass and water as renewable sources is first developed and analyzed with engineering equation solver (EES) through first and second law of thermodynamics and then, optimized through an evolutionary algorithm using the Matlab software package for higher exergy efficiency, lower cost, and lower environmental impact. The vanadium-chlorine (V-Cl) thermochemical cycle is selected for hydrogen production incorporated into cogeneration system. A novel integration of a three-step V-Cl thermochemical cycle, a Brayton power generation cycle and a biomass gasification unit fed by Cladophora glomerata macroalgae as a marine biomass is proposed and investigated in this study. Both exergoeconomic and exergoenvironment analyses are developed to evaluate the performance of the proposed cogeneration system. Also, both power generation system and thermochemical hydrogen production cycle are validated with previous studies in the literature for more accuracy. The proposed system is able to produce a 23.42 kg/h of hydrogen and a total of 885 kW power at the base case condition. Moreover, optimum values for overall exergy efficiency, total cost per unit of exergy, and environmental impacts are 60.45%, 14.46 g.CO2/kWh, 6.36 $/GJ, respectively, where pressure ratio (for Brayton cycle) is 5.87, gasification temperature is 715 °C and biomass mass flow rate is 0.8 kg/s.

Methodological approach to the research of energy cogeneration systems operational reliability indicators

Methodological approach to the research of energy cogeneration systems operational reliability indicators

Methodological approach to the research of energy cogeneration systems operational reliability indicators

Methodological approach to the research of energy cogeneration systems operational reliability indicators

POLAND'S ENERGY SECURITY IN THE CONTEXT OF EU ENVIRONMENTAL INITIATIVES

The current conditions of global development actualize the need for political actors to form a high level of energy security. It expands the state's ability to ensure the sustainability of economic development and the ability to withstand likely threats. The issue of energy security and sovereignty are key on the agenda of the EU, which seeks to implement a strategy of global leadership. The environmental modernization of the EU energy sector and each member state must comply with the main goal of «The European Green Deal», which is to reduce carbon emissions by 55% before 2030. The subject of the study is the substance and peculiarities of the formation of energy security in Poland. The aim of the study is to analyze the mechanisms of energy security of Poland in the context of EU environmental initiatives. Research methodology: systematic approach, method of analysis and comparison. The issue of energy security is recognized as key in achieving sustainable economic development in Poland. The content and basic principles of state energy security are presented in the National Security Strategy and detailed in the Energy Policy. Among the main directions of ecological modernization of the energy sector the following have been identified: efficient consumption of national energy resources; modernization of the energy sector and infrastructure; diversification of natural gas, oil, liquid fuel supplies; optimization of energy market functioning; construction of nuclear power plants; expansion of alternative energy sources; modernization of heating and co-generation energy systems; increasing energy efficiency. Polish officials have emphasized the need for a three-phase energy transition, involving a reduction in the production and use of coal, a gradual increase in the share of natural gas and the expansion of opportunities to use energy from alternative sources. The modernization of Poland's energy sector correlates with the implementation of «The European Green Deal» and other EU environmental initiatives. Energy sovereignty is secured through domestic and foreign financial assistance. The National Fund for Environmental Protection and Water Management of Poland attracts investments in environmental projects related to the development of geothermal energy and improvement of infrastructure energy efficiency. EU special funds (European Regional Development Fund/European Social Fund, Cohesion Fund, Just Transition Fund and Modernization Fund) provide funding for national or regional projects aimed at the comprehensive modernization of the Polish energy sector and the implementation of commitments to achieve climate neutrality. Poland pursues an active policy of cooperation in the energy sphere with other states – Denmark, Lithuania, Latvia, and Estonia. Projects such as "Baltic Pipe" and "The Baltic Synchronisation Project" are in the active implementation phase. The results of the study: energy security is a key factor in the sustainability of economic development of Poland, the implementation of the modernization of the national energy complex correlates with the EU environmental initiatives, which contributes to the attraction of domestic and foreign investment, as well as the resources of public diplomacy.

Thermodynamic evaluation and optimization of a cogeneration energy system integrated with steam network

Cogeneration energy systems are one of the most promising clean, efficient technologies for satisfying industrial energy needs. In this study, a cogeneration system consisting of a solid oxide fuel cell, a gasification unit, a gas turbine cycle, and a steam network module is proposed. This topping system is integrated with a steam network that provides steam for different utilities by recovering steam. Also, biomass –as renewable energy– is used to address the problems of fossil fuels, such as scarcity of resources and environmental issues. The system is evaluated from an energy perspective to ascertain the feasibility of the system. Based on the results, the efficiency attained from this system is 54.35%. An optimization study based on a genetic algorithm is performed to find the best conditions, which indicates an efficiency improvement to 65.06%. Moreover, a parametric study on different steam network pressure levels is taken place, which shows the importance of the VHP header on system performance.

The many-objective optimal design of renewable energy cogeneration system

To alleviate the issues of climate warming and fossil resources depletion, this paper proposes a wind-photovoltaic-thermal energy storage-electric heater cogeneration system, which adopts the structure of concentrated solar power plant but replaces the expensive collector field and tower with wind and photovoltaic farms and electric heater that converts the excess electricity as thermal energy source. The cogeneration system can effectively regulate the fluctuating wind and photovoltaic output to satisfy electricity load by electric heater based on resistive heating of molten salt, two-tank molten salt thermal energy storage and power block based on steam Rankine cycle, and supply heat load directly from the molten salt heat transfer fluid and heat exchanger. This paper considers minimizing levelized cost of energy, loss of power and heat supply probability, energy reduction rate and lifecycle equivalent CO2 emissions as optimized objectives, and investigates the many-objective (having four or more objectives) capacity optimization problem by Nondominated Sorting Genetic Algorithm-Ⅲ coupled with Principal Component Analysis and Technique for order preference by similarity to ideal solution. Moreover, residual analysis is applied to consider the uncertainty of wind power prediction. The detailed optimization process and performance comparison of many-objective algorithms, the all-year energy flow and seasonal output characteristics analysis of the optimal-compromise solution are presented. Finally, the proposed cogeneration system is compared to the power-only system with the same installed capacity and equivalent load demand, and the comparison results show that the proposed cogeneration system performs better in all evaluation metrics. Therefore, the proposed renewable energy cogeneration system is feasible and cost-effective for practical applications.

Preliminary design of AR/SOFC cogeneration energy system using livestock waste

Abstract This paper reports on a sizing procedure for integrated Anaerobic Reactor/Solid Oxide Fuel Cell cogeneration energy system powered by livestock waste, in order to meet the provisions of Industry 4.0, connected to the new paradigm of Agriculture 4.0. The algorithm accounts on two main computational blocks, associated to the biogas production plant and to the SOFC energy unit respectively. A numerical modeling is performed to dimension the anaerobic digester and the biogas production deriving, as well as to dimension the energy unit and determine its techno-energy performance when it is fed by the previous biogas. An application of the algorithm is made to a mid-size livestock farm, in order to valorize the biomass waste produced in situ.

Competitive development of energy cogeneration systems in conditions of economic imbalances

Competitive development of energy cogeneration systems in conditions of economic imbalances

Economic Efficiency Assessment of Using Wood Waste in Cogeneration Plants with Multi-Stage Gasification

The aim of this work is to assess the effectiveness of biomass gasification power plants in Russia (Irkutsk region) and compare them with other types of electricity and heat cogeneration systems. Biomass, which is waste from logging and wood processing, is considered as fuel for gasification plants. As a criterion, the cost of energy is used. Analytical relations are obtained for the cost of electric energy at a given cost of thermal energy and vice versa, thermal energy at a given cost of electric energy. These relationships are applied to assess the economic efficiency and compare small-power plants (up to 200–500 kW) such as mini-combined heat and power (CHP) on fuel chips and fuel pellets, coal-fired CHP and gas and liquid fuel power plants (gas-piston and diesel power plants). The latter are equipped with heat recovery boilers and supply consumers with heat and the electric power simultaneously. The calculation results show that the cost of electricity when using wood fuel is significantly less than the cost of electricity from a diesel power plant due to the use of cheaper fuel. In this regard, for autonomous energy systems of small power, especially near logging points, energy supply from biomass gasification power plants is a preferable solution than the use of diesel power plants. Wood fired energy cogeneration systems (mini-CHP) can also successfully compete with coal and gas power plants if they have cheap wood fuel at their location. With the introduction of carbon dioxide emissions charges, the use of not only wood chips, but also pellets becomes competitive in comparison with coal and gas.

Thermoeconomic Cost Analysis of Solar and Geothermal Energy Powered Cooling and Power Cogeneration

In this study, geothermal and solar energy assisted cogeneration energy system has been modeled to supply residences' electricity and cooling requirements. The geothermal water from the geothermal resource and the heat transfer fluid heated in the parabolic collector is used as the heat source in the absorption cooling system. Electricity is generated in the binary power plant with geothermal water and heat transfer fluid from the absorption cooling system. The generated electricity is supplied to the grid. Thermoeconomic analysis of the system is performed by using the Engineering Equation Solver (EES) program by using geothermal and solar energy values of Afyonkarahisar. The geothermal resource's temperature and mass flow in the system is 130 ºC and 85 kg/s, respectively. The parabolic trough collector operates in the range of monthly average solar radiation values (500-600 W/m2) calculated for the summer season, where cooling is planned. The LiBr-H2O solution is chosen as the refrigerant of the absorption cooling system. The system's parametric study is performed by considering the different geothermal resource temperatures and solar radiation values. According to these results, the unit electricity and unit cooling costs produced in the system will be investigated. The optimum working conditions are investigated in producing and using the energy form (electricity-cooling) requirements.

Experimental thermal performance and modelling of a waste heat recovery unit in an energy cogeneration system

In this paper, the performance of a gas/oil heat recovery unit is assessed experimentally and by the development of an Aspen model and artificial neural networks. The heat recovery unit is a cross-flow heat exchanger used to recover the residual heat of the exhaust gases coming from a microturbine to drive an absorption chiller. The test facility consists mainly of a microturbine, a heat recovery unit, and an air-cooled absorption chiller. The experiments were conducted at partial power loads and different thermal oil mass flows. Regarding the models, the Aspen model depends on inlet conditions, the mechanical description of the heat recovery unit, and the fluids thermophysical properties, whereas the ANN model consists of 3 trained artificial neurons, 4 inputs (inlet flows and temperatures), and 2 outputs (thermal load and overall heat transfer coefficient). The experimental tests show that the recovery unit recovers from 18.8 kW to 8.1 kW when the microturbine power output is varied from 23kWe to 4 kWe. Results also show that the overall heat transfer coefficient ranges between 243 W.m−2.K−1 and 89 W.m−2.K−1, while they evidence that the overall heat transfer resistance is controlled by the exhaust gases heat transfer resistance. Furthermore, simulation results show that the Aspen model predicts the heat recovery unit thermal load and overall heat transfer coefficient with average relative differences of 0.93% and 11.27%, respectively, to the experiments. The ANN model evidences average relative differences of 0.51% and 3.48% for the thermal load and overall heat transfer coefficient, respectively.

Integrated Evaluation Framework of the Cogeneration Energy System via Application of Fuzzy P-graph

Integrated Evaluation Framework of the Cogeneration Energy System via Application of Fuzzy P-graph

Thermodynamic performance analysis of geothermal and solar energy assisted power generation and residential cooling system

In this study, geothermal and solar assisted cogeneration system is modeled to the supply of electricity and cooling. The energy requirements of Afyon Kocatepe University, Faculty of Technology building, are investigated. The building cooling system is performed by using heat energy provided from geothermal and solar energy in an absorption cooling system. Subsequently, it is aimed to generate electricity in the Organic Rankine Cycle (ORC) with geothermal water and waste heat leaving the cycle. It is planned that the electricity produced in the power cycle is supplied to the grid system according to the requirement. The cooling load of the faculty building is calculated by considering the working conditions of the faculty building. The ideal thermodynamic analysis and performance evaluation of the system has been performed by using Engineering Equation Solver (EES) software into consideration by considering the cooling season, geothermal and solar energy data of Afyon in the summer season. The parametric study of the system is performed by considering different geothermal water temperature and solar radiation. The reversible COP of the absorption cooling system is calculated to be 3.18. The maximum heat energy value obtained from solar energy is calculated to be 74.97 kW in June. The highest ideal cooling capacity and maximum power provided from geothermal and solar assisted cogeneration energy systems are calculated to be 40,222 kW and 4688 kW, respectively, in June. These results are sufficient to supply the electrical and cooling requirements of the faculty building.