In this study, the integration of multi-effect desalination (MED) system with cogeneration of heat and power system has been considered. Low-pressure steam in two case studies has been utilized as the motive steam of MED system. R-curve is a powerful tool that can be used to identify fuel utilization amount in different operation points of the cogeneration system. R-curve explains utility system operation improvement procedure without capital cost. By deploying and development of the R-curve concept, the freshwater demand of the total site and total annual cost of the site have been evaluated.These curves can be used as a tool to improve the operation and economic parameters in every operating point of cogeneration system and present comprehensive view about the improvement of utility system operation condition at each operating point. For the first time, R-curve has been used to identify the impact of cogeneration system integration with a thermal desalination system on the cogeneration system operating point. The performance of the cogeneration system can either be enhanced or impaired by integration of desalination system. As demonstrated in a case study, integration of 2.2 MW MED system can either provide 52.765 MW energy saving or deprive 30.257 MW fuel energy based on the operating state of the cogeneration system before and after integration.

This paper aims to examine a combined heating, power, and hydrogen system production using biogas energy. Biogas steam and dry reforming method are designed based on equilibrium data with the EES program. The results show that biogas has two principal roles for combustion and reforming processes simultaneously. The heating energy produced from biogas causes the reforming of biogas and improves the system efficiency by 74%. The maximum exergy efficiency and hydrogen production are obtained at 58.34% and 0.11-0.83 kg/s, respectively. The results also show that the combustion chamber has the highest exergy destruction by about 51% when the amount of electric power plant is considered between 5 to 40 MW. A parametric study for optimizing hydrogen production analyzes the key parameters. The optimal scenarios are when CO2/CH4=0.50-0.66, H2O/CH4=2-3.6, and the reforming temperature is 965-1036K. The conversion of methane and carbon dioxide shows the environmental effect of decreasing greenhouse gases. At 965K or higher, methane and carbon dioxide conversion rates reach 97% and 86%, respectively. This paper aims to develop a novel methodology for identifying thermodynamic cycle conditions and reforming processes only by use of biogas as the source of energy.y y y y y y y y y y

Production systems have experienced rapid growth over the past few years. Based on geothermal energy, the present study explores a unique cogeneration system that includes a proton membrane electrolyzer, the Rankine cycle, and a water-ammonia absorption chiller. The model under study is designed to generate power and hydrogen, as well as cooling, and it is analyzed from an energy and exergy standpoint. For the desuperheater and the absorber, the maximum rate of exergy destruction of the Rankin cycle is 34% and 36%, respectively. Furthermore, a parametric analysis of the system was conducted, and the cogeneration system was optimized from three perspectives: turbine production power, energy efficiency, and exergy. Based on turbine inlet and outlet pressure, turbine power, energy efficiency, and system efficiency are optimized. Moreover, the optimization calculations made from the perspective of turbine production power show that production power values are 101 kW, hydrogen production is 4. 24 liters per second, system energy efficiency is 82. 3%, and the amount of heat absorbed in the evaporator is 57. 6 kW.

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.

In the current study, a new integrated system is provided to prevent waste energy and reduce power consumption. This system consists of a cascade refrigeration system (for cooling) and an Organic Rankine cycle(ORC) (for power generation). These two cycles are combined through a heat exchanger. In fact, this heat exchanger acts as a condenser for the cascade refrigeration cycle and evaporator for ORC. The waste heat of the cascade refrigeration cycle is used to handle the ORC. In this way, a part of the power consumption of the cascade refrigeration cycle is satisfied by ORC. Thermodynamic simulation of the proposed system is carried out via Engineering Equation Solver(EES) software. A parametric study is done to evaluate the effects of the operational parameters on the performance of the integrated system. In addition, different working fluids are used in cascade refrigeration and ORC cycles. The results showed that by using the working fluids of R245fa, R717, and R141b in order in the low-temperature refrigeration cycle, high-temperature refrigeration cycle and ORC, one can produce cooling at -50 ° C and also reduce the power consumption up to 48.69% in the cascade refrigeration cycle.

Regarding the essential role of energy in the development and international competition on energy resources, policymaking for the energy sector technologies is remarkably vital. On the other hand, the first step to technology policymaking is determining the barriers and problems of technology development and then implementing adequate policies. On this basis, this paper aims at providing a model for technology development analysis based on the technological innovation system approach. Compared to other approaches, the causal layered analysis provides a more concise and deeper analysis and consequently more effective policies and also delineates the correlations between different problems. At first, based on the conceptual model of the research, technological innovation system problems were extracted and divided into five categories of functional, structural, contextual, discursive, and visionary problems. Afterward, the intensity of each problem along with the correlations was determined. While the results of the most previous studies suggest the structural and functional problems to be dissolved, the results here reveal the noticeable effect of contextual, discursive, and visionary problems. In the end, some policy suggestions are provided by the authors to address these macro problems.

This study aims to develop, and examine a cogeneration system for electric power, hydrogen, and ammonia production. A modified Rankine cycle is configured to supply power. An electrolyze unit and an ammonia synthesis reactor are used to provide hydrogen and ammonia. The system is investigated from technical and economic aspects. The inquiry outcomes disclose that the reaction pressure and hydrogen to nitrogen molar ratio have mainly affected the ammonia production rate increment. The system energy and exergy efficiencies as well as the total unit cost of the product are at about 50.47 %, 51.41 %, and 638.3 $/GJ, respectively. The results show that the exergy destruction rate of the system is 89.797 MW. Moreover, 6.438 kg/h of hydrogen and 6.528 kg/s of ammonia are attainable. The sweeping sensitivity investigation on the economic aspect reveals that the reaction pressure, input hydrogen molar ratio, and hydrogen to nitrogen molar ratio have a positive effect on the sum unit cost of the product's decrement. Finally, the thermodynamic sensitivity examination outcomes affirm that altering reaction temperature leads to technical inefficiencies of the proposed cogeneration system.

A thermodynamic study of a combined power system is presented in this work, along with the results of that analysis. The leading component is a fuel cell utilizing a Proton Exchange Membrane fuel cell with a novel channel design. This is complemented by an evaporator and an air preheater, which work together to capture waste heat effectively. The analysis is developed in ANSYS Fluent software to simulate cells and obtain all required data. In addition, the Engineering Equation Solver was employed to achieve the expected results from the overall unit system. Based on the results, the total exergy demolition rate is reported about 430.21 kW. Significantly, the exergy degradation in the Proton Exchange Membrane fuel cell stack was the greatest compared to the other components. The cell exergy proficiency was 44.4% regarding the exergy analysis aspect. Also, the Organic Rankine Cycle’s output is 148.17 kW, and the Proton Exchange Membrane fuel cell’s is 1148.2 kW. The obtained data indicate that by going up the density of current, the cell proficiency declines and the highest exergy efficiency belongs to the turbine at 80.3%.