Greenhouse gas emission and exergy assessments of an integrated organic Rankine cycle with a biomass combustor for combined cooling, heating and power production

In this paper, energy and exergy analyses of a trigeneration system based on an organic Rankine cycle (ORC) and a biomass combustor are presented. This trigeneration system consists of a biomass combustor to provide heat input to the ORC, an ORC for power production, a single-effect absorption chiller for cooling process and a heat exchanger for heating process. The system is designed to produce around 500 kW of electricity. In this study, four cases are considered, namely, electrical-power, cooling-cogeneration, heating-cogeneration and trigeneration cases. The effects of changing ORC pump inlet temperature and turbine inlet pressure on different key parameters have been examined to evaluate the performance of the trigeneration system. These parameters are energy and exergy efficiencies, electrical to cooling ratio and electrical to heating ratio. Moreover, exergy destruction analysis is presented to show the main sources of exergy destruction and the contribution of each source to the exergy destruction. The study shows that there are significant improvements in energy and exergy efficiencies when trigeneration is used as compared to electrical power. The results show that the maximum efficiencies for the cases considered in this study are as follows: 14.0% for electrical power, 17.0% for cooling cogeneration, 87.0% for heating cogeneration and 89.0% for trigeneration. On other hand, the maximum exergy efficiency of the ORC is 13.0% while the maximum exergy efficiency of the trigeneration system is 28.0%. In addition, this study reveals that the main sources of exergy destruction are the biomass combustor and ORC evaporator.

Energy and exergy analyses of a biomass trigeneration system using an organic Rankine cycle

Exergy modeling of a new solar driven trigeneration system

Exergy analysis of an integrated solid oxide fuel cell and organic Rankine cycle for cooling, heating and power production

A novel cogeneration system based on a wall mounted gas boiler and an organic Rankine cycle with a hydrogen production unit is proposed and assessed based on energy and exergy analyses. The system is proposed in order to have cogenerational functionality and assessed for the first time. A theoretical research approach is used. The results indicate that the most appropriate organic working fluids for the organic Rankine cycle are HFE700 and isopentane. Utilizing these working fluids increases the energy efficiency of the integrated wall mounted gas boiler and organic Rankine cycle system by about 1% and the organic Rankine cycle net power output about 0.238 kW compared to when the systems are separate. Furthermore, increasing the turbine inlet pressure causes the net power output, the organic Rankine cycle energy and exergy efficiencies, and the cogeneration system exergy efficiency to rise. The organic Rankine cycle turbine inlet pressure has a negligible effect on the organic Rankine cycle mass flow rate. Increasing the pinch point temperature decreases the organic Rankine cycle turbine net output power. Finally, increasing the turbine inlet pressure causes the hydrogen production rate to increase; the highest and lowest hydrogen production rates are observed for the working fluids for HFE7000 and isobutane, respectively. Increasing the pinch point temperature decreases the hydrogen production rate. In the cogeneration system, the highest exergy destruction rate is exhibited by the wall mounted gas boiler, followed by the organic Rankine cycle evaporator, the organic Rankine cycle turbine, the organic Rankine cycle condenser, the proton exchange membrane electrolyzer, and the organic Rankine cycle pump, respectively.

Exergy and greenhouse gas emission analyses are performed on a novel trigeneration system driven by a solid oxide fuel cell (SOFC). The trigeneration system also consists of a generator-absorber heat exchanger (GAX) absorption refrigeration system and a heat exchanger to produce electrical energy, cooling and heating, respectively. Four operating cases are considered: electrical power generation, electrical power and cooling cogeneration, electrical power and heating cogeneration, and trigeneration. Attention is paid to numerous system and environmental performance parameters, namely, exergy efficiency, exergy destruction rate, and greenhouse gas emissions. A maximum enhancement of 46% is achieved in the exergy efficiency when the SOFC is used as the primary mover for the trigeneration system compared to the case when the SOFC is used as a stand-alone unit. The main sources of irreversibility are observed to be the air heat exchanger, the SOFC, and the afterburner. The unit CO2 emission (in kg/MWh) is considerably higher for the case in which only electrical power is generated. This parameter is reduced by half when the system is operated in a trigeneration mode.

Analysis of exhaust waste heat recovery from a dual fuel low temperature combustion engine using an Organic Rankine Cycle

Waste heat recovery in CO2 compression

Greenhouse gas emission and exergo-environmental analyses of a trigeneration energy system

Aceh as one of Indonesian province has some hot springs potencies that can be utilized to generate electricity by organic Rankine cycle (ORC) system. This paper discusses energy and exergy assessment of ORC with hot spring as the heat source in Aceh, Indonesia. Energy and exergy assessment are utilized to evaluate ORC performance. The performance are evaluated from the hot springs that have temperature difference with cooling fluid temperature more than 40°C and the flow rate more than 30 liter/minute. Lokop-1 (93.5°C, 26.2°C, 3000 liter/minute), Lokop-2 (87°C, 27°C, 180 liter/minute), and Lokop-3 (76.5°C, 27°C, 60 liter/minute) are the hot springs location that meet the specified criteria. The working fluid and cooling fluid chosen in this study are R227ea and water. The cooling water temperature is assumed equal to the ambient air temperature. Theoretic electricity power, thermal efficiency, exergy efficiency, total exergy destruction, and exergy destruction rate in each equipment are evaluated in this research. The calculation results of the theoretic electricity power, thermal efficiency, and exergy efficiency, respectively, are Lokop-1 (168.3 kW, 7.77%, 7.21%), Lokop-2 (9 kW, 7.04%, 6.51%), and Lokop-3 (2.4 kW, 5.7%, 5.25%). Lokop-1 has the highest total exergy destruction. The exergy assessment from exergy destruction rate in each equipment show that the maximum exergy destruction occurs in the evaporator.

Background: Concentrated solar power (CSP) technology has been gaining more and more attention due to its inherent sustainable merit. Further promotion of sustainability requires the effective utilization of concentrated solar thermal radiations which can achieve through combined cooling, heat and power. In this context, the key objective of the research carried out in the present study was to propose and develop a novel solar thermal-driven combined cooling, heating, and power system for producing power of 7MW. Objective: The objective of the study is to reduce heat loss at various places and to increase the overall energy and exergy efficienices of the system. The effect of very influencing parameters like direct normal irradiance (DNI), extraction pressure, turbine back pressure, turbine inlet pressure, and pump inlet temperature were ascertained on energy and exergy efficiencies for the trigeneration system. In addition, the model was extended to incorporate the evaluation to identify the causes and locations of thermodynamic imperfections. The energy and exergy efficiency and destruction were also evaluated. Methods: For this study, a solar-driven combined cooling, heating, and electric power generation system is called the trigeneration system was designed by coupling a solar-based heliostat and centralized solar receiver with a conventional Rankine-based cycle. The conventional Rankine cycle comprises a basic heat recovery generator, a steam turbine, a condenser, and eventually a pump. A thermodynamic model was developed which presented the analysis of various thermodynamic-based parameters of the integrated system comprising a solar-driven absorption refrigeration cycle. The analysis is formulated based on a cascaded system that grabs the energy and exergy-based methods in which the mass, energy, and exergy are balanced. Results: The system was run for the solar radiation range from 600 to 1000W/m2. It is found that the overall efficiency of the trigeneration system increases by 32 to 35% when DNI changed from 600 to 1000W/m2. The inlet temperature of the pump also increases from 90 to 110℃ and it can increase the overall efficiency by 2.73%. A considerable increment is observed of energy by 4000kW to 6800kW when the DNI increases from 600W/m2 to 1000W/m2. The energy destruction is also observed during the process followed at the Turbine, heat recovery steam generators (HRSG), and in the components of vapour absorption refrigeration. The exergy destruction is also identified at the central receiver of about 33%, and the next 25% in heliostat. The annual CO2 mitigated is estimated by 1437.16MMT/year for the year 2022 in India by the application of CSP plants. Conclusion: The result reveals tar the central receiver and heliostat of the solar field endanger the higher thermodynamics irreversibility of about 33% and 25% respectively. The trigeneration process can be utilized the low temperature for other applications, that is why the overall cycle efficiency will be increased. The trigeneration cycle with HRSG is the future technology and due to this cycle, CO2 can also being reduced.

This paper proposes a comparative performance analysis based on 4-E (Energy, Exergy, Environment, and Economic) of a bottoming pure Ammonia (NH3) based Organic Rankine Cycle (ORC) and Ammonia-water (NH3-H2O) based Kalina Cycle System 11(KCS 11) for additional power generation through condenser waste heat recovery integrated with a conventional 500MWe Subcritical coal-fired thermal power plant. A typical high-ash Indian coal is used for the analysis. The flow-sheet computer programme ‘Cycle Tempo’ is used to simulate both the cycles for thermodynamic performance analysis at different plant operating conditions. Thermodynamic analysis is done by varying different NH3 mass fraction in KCS11 and at different turbine inlet pressure in both ORC and KCS11. Results show that the optimum operating pressure of ORC and KCS11 with NH3 mass fraction of 0.90 are about 15 bar and 11.70 bar, respectively and more than 14 bar of operating pressure, the plant performance of ORC integrated power plant is higher than the KCS11 integrated power plant and the result is observed reverse below this pressure. The energy and exergy efficiencies of ORC cycle are higher than the KCS11 by about 0.903 % point and 16.605 % points, respectively under similar saturation vapour temperature at turbine inlet for both the cycles. Similarly, plant energy and exergy efficiencies of ORC based combined cycle power plant are increased by 0.460 % point and 0.420 % point, respectively over KCS11 based combined cycle power plant. Moreover, the reduction of CO2 emission in ORC based combined cycle is about 3.23 t/hr which is about 1.5 times higher than the KCS11 based combined cycle power plant. Exergy destruction of the evaporator in ORC decreases with increase in operating pressure due to decrease in temperature difference of heat exchanging fluids. Exergy destruction rate in the evaporator of ORC is higher than KCS11 when the operating pressure of ORC reduces below 14 bar. This happens due to variable boiling temperature of NH3-H2O binary mixture in KCS11 and resulting in less irreversibility during the process of heat transfer. Levelized Cost of Electricity (LCoE) generation and the cost of implementation of ORC integrated power plant is about Rs.1.767/- per kWh and Rs. 2.187/- per kg of fuel saved, respectively whereas, the LCoE for KCS11 based combined power plant is slightly less than the ORC based combined cycle power plant and estimated as about Rs.1.734 /- per kWh. The cost of implementation of KCS11 based combined cycle power plant is about Rs. 0.332/- per kg of fuel saved. Though the energy and exergy efficiencies of ORC is better than KCS11 but considering the huge investment for developing the combined cycle power plant based on ORC in comparison with KCS11 below the operating pressure of 14 bar, KCS11 is superior than NH3 based ORC.

Energy, exergy analysis in a hybrid power and hydrogen production system using biomass and organic Rankine cycle

The current study aimed at delving into the thermodynamic study of a trigeneration cycle based on biomass fuel, combined with an Organic Rankine Cycle (ORC) and an absorption chiller. Biomass fuel is purely produced from Municipal Solid Waste (MSW). Energy and exergy analyses were carried out using the solar collector employing optimized characteristics to provide the required thermal energy at the ideal condition to utilizing in the high-temperature gasification process having hot steam. For supplying electricity, heating and cooling power, a Rankine cycle including a turbine, a heater, and a single effect absorption chiller was considered. To solar energy exploitation, a parabolic trough solar collector and hot steam gasifier were utilized. ORC can efficiently recover low-grade waste heat due to its excellent thermodynamic performance. Based on the examinations, the effects of critical thermodynamic parameters on the exergy efficiency and optimization of the trigeneration cycle and ORC with R134a, as working fluid, was conducted to achieve the system optimization design from thermodynamic aspect through Genetic Algorithm (GA). In this study, exergy destruction and its percentage in the power generation process were calculated as well. Results indicated that the studied system has the potential to generate 11.2 kW electricity, 17.4 kW heating power, 15.3 kW cooling power with the energy and exergy efficiencies of 64.3 % and 52%. It was also revealed that the output power of this system is fixed on the constant amount of 11.2 KW, which is obtained from the microturbine and ORC turbine. Additionally, it was demonstrated that the most exergy destructions are for gasifier, compressor, and combustor respectively, containing 47 %, 26.3 % and 14 % of the destructions. Finally, the optimized performance of the system was determined using GA and exergy efficiency as an objective function. The optimized trigeneration energy system could yield the exergy efficiency of 4.4%.

In this study, a cooling/power cogeneration cycle consisting of vapor-compression refrigeration and organic Rankine cycles is proposed and investigated. Utilizing geothermal water as a low-temperature heat source, various operating fluids, including R134a, R22, and R143a, are considered for the system to study their effects on cycle performance. The proposed cycle is modeled and evaluated from thermodynamic and thermoeconomic viewpoints by the Engineering Equation Solver (EES) software. Thermodynamic properties as well as exergy cost rates for each stream are found separately. Using R143a as the working fluid, thermal and exergy efficiencies of 27.2% and 57.9%, respectively, are obtained for the cycle. Additionally, the total product unit cost is found to be 60.7 $/GJ. A parametric study is carried out to determine the effects of several parameters, such as turbine inlet pressure, condenser temperature and pressure, boiler inlet air temperature, and pinch-point temperature difference, on the cycle performance. The latter is characterized by such parameters as thermal and exergy efficiencies, refrigeration capacity, produced net power rate, exergy destruction rate, and the production unit cost rates. The results indicate that the system using R134a exhibits the lowest thermal and exergy efficiencies among other working fluids, while the systems using R22 and R143a exhibit the highest energy and exergy efficiencies, respectively. The boiler and turbine contribute the most to the total exergy destruction rate.