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Among the various solar technologies, solar power tower (SPT) technology is being widely used for large-scale energy generation. Therefore, this work developed a trigeneration system for SPT plant that produces power, heating and cooling at low temperature efficiently from a high temperature SPT heat source. In order to create heating and low temperature (at −20°C) cooling benefits for food preservation, this trigeneration unit integrates a cascaded vapor compression-absorption refrigeration system combined with a helium Brayton cycle for power generation. The exergy-energy analysis was performed by the numerical technique using engineering equation solver software to evaluate the performance of the proposed SPT plant. The power output, exergy and energy efficiency of the SPT plant were found as 14,865 kW, 39.53% and 28.82%, respectively. The coefficient of performances values for cooling and heating were observed as 0.5391 and 1.539, respectively. Exergy evaluation revealed that approximately 78.18% of the total energy destruction of the entire plant is attributed to the solar subsystem only. Furthermore, a parametric investigation shows that the temperature of the evaporator, generator and helium turbine inlet, and the efficiency of the heliostat and receiver all have a significant impact on the plant performance. Furthermore, a comparative analysis with relevant previous studies has shown that the proposed system outperforms systems based on supercritical CO2 cycles and the Rankine cycles. [ABSTRACT FROM AUTHOR]

In the present work, helium serves as the primary working fluid within the supercritical Brayton cycle, employed to generate power through a solar power tower system. The conventional Brayton cycle for recovering the wasted heat is combined with a cascaded vapor absorption-compression refrigeration system to increase the overall system's performance. Additional benefits of this integrated system include the ability to supply enhanced heating and cooling for food storage applications at lower temperatures. A comprehensive analysis of the combined system was conducted based on exergy, energy, and exergo-environmental (3E) factors a using computational technique engineering equation solver. The combined system's energy, exergy efficiency, and power output were determined to be 28.82%, 39.53%, and 14.865 kW, respectively. The coefficient of performances for cooling and heating were observed as 0.5391 and 1.539 respectively. Approximately 78.18% of the total exergy destruction within the entire plant can be attributed to the solar subsystem, which amounts to 22.763 kW. As direct normal irradiance rises, the environmental impact index decreases from 1.6504 to 0.6801, while the system's environmental stability factor improves, increasing from 0.3773 to 0.5952. Moreover, the parametric assessment highlights the substantial influence of heliostat and receiver efficiencies, as well as the helium turbine's inlet temperature, on the trigeneration system's performance. In addition, compared to previously published research, the current proposed system outperforms supercritical CO2 cycle systems and the conventional steam Rankine cycle systems. [ABSTRACT FROM AUTHOR]

The present study proposes a novel system for power, heat, and hydrogen generation comprising a biomass gasification unit, Rankine cycle, dual-fuel combustion engine, and a waste heat recovery unit. Exhausting hot gases from the engine is recovered for the gasification of the biomass. A part of the generated hydrogen serves as the second fuel in a Heptane-fueled engine to improve its performance. Energy and exergy analyses are carried out for Sugarcane bagasse, Rice Straw, Wheat Straw, and Rice Husk biomass fuels. A good consistency can be seen between the findings of the current study and experimental reports in the literature. The developed trigeneration system improved both exergy efficiency and thermal efficiency by 19% when compared to the conventional system. The exergy efficiency is maximized by using sugarcane bagasse. Furthermore, the results show that Wheat Straw has a maximum total thermal efficiency of 95%. The maximum system exergy destruction of 54% is observed by using Rice Straw and Rice Husk. [ABSTRACT FROM AUTHOR]

A novel hybrid system using geothermal energy and fuel gas in a co-feed structure is proposed. The main objectives include improving the sustainability of a gas turbine cycle associated with a geothermal power plant and reducing carbon emissions. To this end, a novel multi-waste heat recovery process was developed in which the heated airflow in the gas turbine cycle was directed to the geothermal flash cycle to increase the viability of the flash process in this unit. A parallel heat recovery structure then used part of the waste heat from the gas turbine cycle to start a supercritical carbon dioxide cycle and also improve the performance of the geothermal flash cycle. Hence, two organic Rankine cycles were used in the geothermal flash cycle. The other part of the waste heat from the gas turbine cycle was consumed in a cascade framework in a steam Rankine cycle and a desalination plant in combination with a domestic water heater. The defined structure was simulated and a comprehensive study was done from the viewpoints of energy, exergy, environment, and thermoeconomics. This structure reduced the total irreversibility as well as the carbon dioxide emissions compared to the existing literature data. • Proposal of an innovative process based on gas turbine cycle and geothermal energy. • Application of Aspen HYSYS simulation, 4E analysis, and parametric study. • This system produces 121200 kW of power, 30.03 kg s of fresh water, and 205.16 kg s of heat. • Energy and exergy efficiencies and products' unit cost of are 49%, 36%, and 12.79 $ GJ. • CO2 footprints related to the power and all the products are 0.55 and 0.387 kg CO 2 kWh. [ABSTRACT FROM AUTHOR]

The present investigation analyzes in deep a multi-generation system producing power, heating, and domestic consumable water. The system is based on renewable energy sources with approaches utilizing subterranean geothermal reservoir, allocating a considerable potential for means of generation. The system is comprised of a single-flash geothermal system, a dual-turbine Kalina cycle, an Organic Rankine Cycle with an internal heat exchanger and an open feed open heater, a supercritical CO 2 , and a reverse osmosis cycle. The analyzes carried out include energy, exergy, entransy, and exergoeconomic evaluation. Considering the base mode, the values are derived as 46.08%, 56.04%, 333.1MWK, and 16.89$/GJ for energy efficiency, exergy efficiency, entransy loss, and the sum unit cost of products. The coupling of the cycles demonstrated a novel configuration aimed at generating power, heating, and freshwater as a multi-generation system with substantial output potential. The outputs are total power output, heating load, and freshwater as 130.068 MW, 30.79 MW, and 44.97 kg/s, respectively. The remainder of the study includes four multi-objective optimization scenarios aimed at identifying the optimum conditions associated with energy efficiency, exergy efficiency, entransy loss, and the sum unit cost of products. The present investigation uses the Engineering Equation Solver to simulate the conditions of the concept. [ABSTRACT FROM AUTHOR]

Due to the increment of energy demand, the current requirement for optimum design of a trigeneration system has become more imperative than ever. The present work deals with the simulation of the demand energy and optimization of a trigeneration system for a hotel building in Mashhad using GAMS software where four objective functions including energy, exergy, environment, and economy have been considered. The results indicate that the improvement of the objective functions was 30.88%, 30.90%, 30.76%, and 17.19%, respectively, compared to the traditional system. Lastly, advanced exergy analysis was performed on the trigeneration system to determine the amount and location of endogenous, exogenous, avoidable, and unavoidable irreversibility rates. The results elucidate that the gas engine has the highest potential in the efficiency improvement, followed by heat exchangers set, electrical chiller, absorption chiller, and gas boiler. [ABSTRACT FROM AUTHOR]

Biofuels have become a source of renewable energy to offset the use of fossil fuels and meet the demand for electricity, heat, and cooling in the industrial sector. This study aims to (a) develop a simulation of a trigeneration system based on a gas turbine cycle and an absorption chiller unit, using biomass and syngas from spent coffee grounds (SCGs) to replace the conventional system currently supplying the energy requirements of an instant coffee plant located in Guayaquil, Ecuador, and (b) carry out an exergoeconomic analysis of the simulated system to compare the effects of different fuels. The results showed an increase in the exergetic efficiency from 51.9% to 84.5% when using a trigeneration system based on biomass instead of the conventional non-integrated system. Furthermore, the biomass-based system was found to have the lowest operating costs ($154.7/h) and the lowest heating, cooling, and power costs ($10.3/GJ, $20.2/GJ, and $23.4/GJ, respectively). Therefore, the results of this analysis reveal that using SCGs as biofuel in this instant coffee plant is feasible for producing steam, chilled water, and power. [ABSTRACT FROM AUTHOR]

In the current study, biomass was employed as the primary fuel in a multigenerational system to produce power, heat, and hydrogen. Biomass gasification unit, dual fuel homogeneous charge compression ignition (HCCI) engine, Rankine cycle, and waste heat recovery units are the main components of the developed system. The engine exhaust gas contains waste heat which can be utilized for biomass gasification. Hydrogen is the main output of the system whose specific fraction is introduced to the Heptane fueled HCCI engine. The results of the gasification unit and HCCI engine are in good agreement with the experimental reports in the literature. The cold gas and hydrogen efficiencies of the biomass gasification unit were 73% and 34%, respectively. Furthermore, the use of hydrogen as an additional fuel to the heptane-fueled HCCI engine improved the performance of the engine. Except for N O x , other emissions showed a decline. Results indicated that energy efficiency exceeded 57%, while the energy efficiency of the HCCI engine is 38%. Moreover, the exergy efficiency increased from 29% in the single HCCI engine to 47% in the proposed system. • A novel clean biomass-driven three-generation is proposed. • The novel system can produce power, heat and Hydrogen. • The cold gas and hydrogen efficiencies are 68% and 32%, respectively. [ABSTRACT FROM AUTHOR]

Processing of waste materials for the generation of renewable fuels, and the development of trigeneration systems are known as the sustainable procedure for satisfying the diverse energy demands. In this regard, this study aims at developing and analyzing a trigeneration system which consists of a gasifier, combined power cycle, and a vapor absorption refrigeration (VAR) system. A model based on equilibrium thermodynamics was developed which has considered the tar formation and char conversion, and accordingly, composition of biomass derived syngas was predicted by employing the MATLAB software. The gasifier operating performance is assessed for the effect of change in gasification equivalence ratio (GER), steam-to-biomass ratio (SBR), and type of biomass feed. Increase in GER from 0.3 to 0.6 for saw dust gasification reduces the energy and exergy efficiencies of gasifier from 44% to 27.5%, and from 51% to 34%, respectively. Finally, a computational method for the energetic and exergetic assessment of the trigeneration was developed using the EES software and a parametric analysis was conducted. CCHP system efficiencies are found considerably influenced by change in SBR and type of biomass feed. Having 40% second law efficiency gasifier has been determined as the most exergy destructive component in the system proposed.

Nowadays, with increasing energy consumption, global warming, and many problems caused by weather conditions, the tendency to use novel methods of energy generation with high efficiency and low cost that reduce environmental pollution has increased. This study investigates the feasibility of using gas pressure energy recovery in natural gas pressure reduction stations by turboexpanders for cogeneration of power and refrigeration. Turboexpanders and compression refrigeration cycles are employed to recover the energy from natural gas pressure reduction stations. Then, natural gas along with the compressed air enters the Brayton power generation cycle and its waste heat is used in the carbon dioxide (CO2) power generation plant, multistage Rankine cycle, and multi-effect thermal desalination unit. This integrated structure generates 105.6 MW of power, 2.960 MW of refrigeration, and 34.73 kg s−1 of freshwater. The electrical efficiencies of the Rankine power generation cycle, CO2 power generation plant, and the whole integrated structure are 0.4101, 0.4120, and 0.4704, respectively. The exergy efficiency and irreversibility of the developed integrated structure are 60.59% and 68.17 MW, respectively. The exergy analysis of the integrated structure shows that the highest rates of exergy destruction are related to the combustion chamber (59.68%), heat exchangers (14.70%), and compressors (14.46%). The annualized cost of the system (ACS) is used to evaluate the developed hybrid system. The economic analysis of the integrated structure indicated the period of return, the prime cost of the product, and capital cost are 2.565 years, 0.0430 US$ kWh−1, and 372.3 MMUS$, respectively. The results reveal that the period of return is highly sensitive to the electricity price, such that the period of return in the developed integrated structure is less than 5 years for the electricity price of 0.092 US$ kWh−1 and more. Also, the period of return is less than 5 years for the initial investment cost of 632.9 MMUS$ and less, which is economically viable. [ABSTRACT FROM AUTHOR]

In this paper, conventional and advanced exergy analyses are comprehensively introduced on an innovative transcritical CO2 energy storage based trigeneration system. Conventional exergy analysis can quantify in an independent way the component exergy destruction. However, the advanced technology is able to evaluate the interactions among components and identify the tangible promotion potential by allowing for the technical and economic limitations. In this method, the component exergy destruction is separated into avoidable and unavoidable parts, as well as the endogenous/exogenous parts. Calculation of the split parts is carried out by utilizing the thermodynamic cycle-based approach. Results coming from conventional exergy analysis indicate that the first three largest exergy destructions are given by cold storage, compressor 1, and heat exchanger 3. However, advanced analysis results demonstrate that the cold storage, compressor 1, and compressor 2 should be given the first improvement priority in sequence by depending on the avoidable exergy destruction. The turbine efficiency produces a higher impact on overall exergy destruction than compressor efficiency. The pinch temperature in cold storage causes the highest effect on exergy destruction amongst all the heat exchangers. There exists an optimum value in the compressor inlet pressure and ambient temperature. [ABSTRACT FROM AUTHOR]

Environmental concerns and the limitations of conventional energy drive the exploration of reliable renewable sources. Herein, a biomass-assisted trigeneration system in conjunction with a methane-fed gas turbine cycle for generating power, cooling, and heating, and an attempt has been made to maximize the energy extraction from the energy source. The proposed system includes a steam Rankine cycle, a gas turbine unit, and a Kalina subsystem, and is investigated from energetic, exergetic, and economic viewpoints. A comprehensive parametric evaluation is carried out, and a multi-objective grey wolf optimization algorithm integrated with the LINMAP decision-maker method is employed to detect the most optimum point through two different scenarios. By conducting a base study, a net output power of 5926 kW, cooling load of 36.56 kW, heating load of 843.4 kW, and an energetic efficiency of 47.41 % can be achieved. The exergetic and economic standpoints bring out an exergy destruction rate of 7697.07 kW, cycle exergetic efficiency of 41.44 %, and a net present value of 12.420 $M that sequels to a payback period of 5.56 years. Biomass proves reliable in multigeneration systems, emphasizing the pivotal role of studies in maximizing energy extraction for diverse product outputs. • Biomass-assisted trigeneration system for power, cooling, heating. • Conducting energetic, exergetic, and economic analyses. • Optimal operation using multi-objective grey wolf optimization. • Net output power: 5926 kW, cooling load: 36.56 kW, heating load: 843.4 kW. • Exergetic efficiency: 41.44 %, net present value: 12.420 $M. [ABSTRACT FROM AUTHOR]

In this paper four different air conditioning systems designed for a building located in Naples, are investigated. The first plant is based on distributed energy conversion systems: twelve boilers and twelve chillers. In the second solution the space heating demand is satisfied by a centralised boiler while the cooling load is met by a centralised chiller. The third option consists of a trigeneration plant. The fourth configuration is composed by an electric heat pump satisfying space heating and cooling and a centralised boiler used for domestic needs. Dynamic simulations have been carried out to compare the energy and environmental performance of the centralised systems with those achieved by the distributed one. Besides, as further loads, for the third option, two electric vehicles charged by the cogenerated electricity surplus are compared to diesel cars. The results show that the best energy and environmental performance are achieved by the cogenerator-based system, with a primary energy demand of 120.6 MWh/y and equivalent dioxide carbon emissions of 25.2 t/y in the configuration without vehicles. This result is also confirmed with electric and diesel vehicles. The energy competitiveness of the plant with the electric heat pump is achieved only in a scenario with a high penetration of renewable energy sources. • Autonomous and centralised air conditioning systems are compared. • Dynamic simulations are performed to carry out energy and environmental analyses. • A multi-purpose block of flats is considered as users simulated. • Electric and diesel vehicles are introduced in the analysis. • A sensitivity analysis is carried out considering the renewable energy sources contribution. [ABSTRACT FROM AUTHOR]

A novel trigeneration system of cooling, heating and power based on biomass is designed in current study. This system consists of five parts: biomass gasification subsystem, steam turbine subsystem (Rankin cycle), gas turbine subsystem (Brayton cycle), Kalina subsystem and ejector refrigeration subsystem. Energy, exergy and exergy-economic analysis were performed on the whole system and the effects of different key parameters on energy efficiency and exergy and economic factors are investigated. The designed cycle has been qualitatively optimized using DOE method and the interaction effects of parameters on cycle performance has been investigated. The results show that the highest exergy destruction is related to the combustion chamber with 56.14 %. Also, the lowest exergy destruction is assigned to the separator of the Kalina cycle with a nearly zero value. The highest investment, operating and maintenance costs are related to air compressor, gas turbine and steam generator, respectively. The results of parametric analysis showed that with increasing the mixing ratio of natural gas to syngas the thermal and exergy efficiencies, the rate of total system cost and the unit cost of power generation increase. Also, with increasing gasification temperature, the thermal and exergy efficiencies of this system vary slightly and can be considered constant, but the total cost of system increases. The results of DOE analysis showed that among the main effects of the parameters, the isentropic efficiency of the gas turbine and the temperature of the air entering the combustion chamber have the greatest effect on the system efficiency, and the GMR has the greatest effect on the LCOE of the system, and among the interaction effects of the parameters, the interaction between the temperature of the air entering the combustion chamber has the greatest effect on the system efficiency and LCOE. • A novel CCHP system based on biomass is proposed. • This system consists of biomass gasification subsystem, Rankine, Brayton and Kalina power cycles and Ejector refrigeration subsystem. • Cogeneration cycle is optimized based on DOE method and interaction effects of parameters are investigated. • The largest exergy destruction belongs to the gas turbine subsystem at approximately 93 % followed by the biomass gas subsystem at approximately 6 %. • The interaction between the air temperature and combustion gases has the greatest effect on the system efficiency and LCOE. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon cost is integrated into the exergo-economic method. • The costs and carbon footprints of products are allocated in exergy and energy level. • Exergy, cost, and carbon flows of fuel cell trigeneration system are revealed. • Alternative schemes of waste heat utilization are assessed in energy, cost, and carbon. • Exergy and carbon cost compositions of different products are compared. The accompanying exergy-cost-carbon nexus in trigeneration systems brings challenges to distinguishing the formation mechanisms of costs and carbon footprints of power, cold, and heat. In this paper, a fuel cell trigeneration system based on biomass gasification is constructed, and seven optional system configurations are designed according to the waste heat utilization methods including organic Rankine cycle, absorption cycle, and heat exchange. A novel exergy-based cost and carbon footprint model based on the energy levels of energy streams is proposed to obtain the allocation rules of multiple products of the trigeneration system, in which carbon cost with exergy cost is integrated into the exergo-economic method. Using this method, the coupling relationships of exergy-cost-carbon are illustrated and the unit exergy-carbon costs and carbon footprints of electricity, cold, and heat are determined. To select the optimum configuration, a multi-criteria decision-making method, considering energetic, economic, and environmental aspects, is employed to calculate their compositive scores, in which the integrated weights of indicators combine the experts' knowledge and opinions with the entropy information of numerical performances of alternative trigeneration configurations. The sensitivities of exergy-cost and exergy-carbon performances on operation time, carbon footprint of biomass, and interest rate are implemented to discuss their influences. The consideration of energy level increases the cost and carbon footprint of power from fuel cells by around 30%. The carbon cost of system power, chilled water, and hot water account for 5.18%, 6.89%, and 5.25% of their corresponding total exergy-carbon costs. The integration of biomass gasification, fuel cell, gas turbine, and heat exchanger achieves the best comprehensive performance. [ABSTRACT FROM AUTHOR]

Enhancing the stability and cost-effectiveness of gas turbine power plants while mitigating input costs, co-feed arrangements, and multi-heat recovery processes shows great promise. The present study introduces an innovative trigeneration application to energetically and economically modify the existing gas turbine cycle. This trigeneration system incorporates several components, namely a helium gas turbine power plant, a regenerative steam Rankine cycle, a domestic water heating unit, and a multi-effect desalination subsystem. The thermodynamic and economic factors were considered to assess the performance indexes. Furthermore, a thorough technical analysis was conducted on the thermodynamic and economic variables, considering the influence of five crucial decision-making factors. Also, the operation mode of the system was optimized through multi-objective optimization of power and heating load. The outcomes of this optimization process revealed that the optimal values for electric power and heating load are 507.34 kW and 261.94 kW, respectively. Additionally, the capacity of freshwater obtained of about 0.076 kg/s. The optimal solution also showcased an exergy efficiency of 44.93 % and a relatively short payback period of 4.68 years, indicating the system's cost-effectiveness and favorable performance. • Blending flue gas from a gas turbine power plant and syngas from biomass gasification. • Feeding a novel trigeneration model to deliver power, heated water, and freshwater. • Thermodynamic-economic analysis, sensitivity study, and multi-objective optimization. • Optimal power, heated water, and freshwater are 507.34 kW, 261.94 kW, and 0.076 kg/s. • Optimal exergy efficiency and payback period are 44.93 % and 4.68 years. [ABSTRACT FROM AUTHOR]

This paper proposes a natural gas assisted solar low-concentrating photovoltaic/thermal trigeneration (NG-LCPV/T-TG) system. This novel system simultaneously provides electrical, thermal and cooling energy to the user. The design and dynamic simulation performance of the NG-LCPV/T-TG system is completed using Transient System Simulation (TRNSYS) software. The results show that the system can satisfy the requirements of the cooling and heating load. The proposed system maintains the experimental room temperature at about 25 °C under the cooling mode, at about 20 °C under the heating mode. The electrical and thermal energy produced by the low-concentrating photovoltaic/thermal (LCPV/T) system are 3819 kWh and 18,374 kWh. Meanwhile, the maximum coefficient of performance (COP) of the low temperature heat pump (LHP), high temperature heat pump (HHP) and chiller are 5, 2.2 and 0.6, respectively. This proposed system realizes the coupling of natural gas and solar energy in a building. In summary, this trigeneration system is feasible and it promotes the implementation of building integrated high-efficiency energy supply system.

In this paper, conventional and advanced exergy analyses are comprehensively introduced on an innovative transcritical CO2 energy storage based trigeneration system. Conventional exergy analysis can quantify in an independent way the component exergy destruction. However, the advanced technology is able to evaluate the interactions among components and identify the tangible promotion potential by allowing for the technical and economic limitations. In this method, the component exergy destruction is separated into avoidable and unavoidable parts, as well as the endogenous/exogenous parts. Calculation of the split parts is carried out by utilizing the thermodynamic cycle-based approach. Results coming from conventional exergy analysis indicate that the first three largest exergy destructions are given by cold storage, compressor 1, and heat exchanger 3. However, advanced analysis results demonstrate that the cold storage, compressor 1, and compressor 2 should be given the first improvement priority in sequence by depending on the avoidable exergy destruction. The turbine efficiency produces a higher impact on overall exergy destruction than compressor efficiency. The pinch temperature in cold storage causes the highest effect on exergy destruction amongst all the heat exchangers. There exists an optimum value in the compressor inlet pressure and ambient temperature.

The energy and power sectors are critical sectors, especially as energy demands rise every year. Increasing energy demand will lead to an increase in fuel consumption and CO2 emissions. Improving the thermal efficiency of conventional power systems is one way to reduce fuel consumption and carbon emissions. The previous study has developed a new methodology called Trigeneration System Cascade Analysis (TriGenSCA) to optimise the sizing of power, heating, and cooling in a trigeneration system for a Total Site system. However, the method only considered a single period on heating and cooling demands. In industrial applications, there are also batches, apart from continuous plants. The multi-period is added in the analysis to meet the time constraints in batch plants. This paper proposes the development of an optimal trigeneration system based on the Pinch Analysis (PA) methodology by minimizing cooling, heating, and power requirements, taking into account energy variations in the total site energy system. The procedure involves seven steps, which include data extraction, identification of time slices, Problem Table Algorithm, Multiple Utility Problem Table Algorithm, Total Site Problem Table Algorithm, TriGenSCA, and Trigeneration Storage Cascade Table (TriGenSCT). An illustrative case study is constructed by considering the trigeneration Pressurized Water Reactor Nuclear Power Plant (PWR NPP) and four industrial plants in a Total Site system. Based on the case study, the base fuel of the trigeneration PWR NPP requires 14 t of Uranium-235 to an average demand load of 93 GWh/d. The results of trigeneration PWR NPP with and without the integration of the Total Site system is compared and proven that trigeneration PWR NPP with integration is a suitable technology that can save up to 0.2% of the equivalent annual cost and 1.4% of energy compared to trigeneration PWR NPP without integration.

Abstract Energy recovery is one of the most important ways to clean production and reduce of carbon dioxide emission. Therefore, in this paper, a trigeneration system (combined cooling, heating and power or CCHP) is suggested to reduce fuel consumption and pollutant emission for building applications. The system consists of two beta-type Stirling engines as prime movers, a heat recovery system, an absorption chiller, and a power generator. The Stirling engine has been modeled based on a non-ideal adiabatic analysis in which the frictional and thermal losses of the engine have been considered using a developed numerical code. For model validation, the specifications of the GPU-3 Stirling engine have been used and the results have been compared with the experimental data and previous models. Moreover, the energy modeling of the absorption chiller has been performed using Stirling engine waste heat. Then, the effects of engine rotational speed, wall temperature of heater, and regenerator length on efficiency, fuel consumption, and carbon dioxide emissions reduction have been studied and the appropriate values have been presented. The results show that in these conditions, the appropriate values for the electrical efficiency and trigeneration efficiency are 27.31% and 74%, respectively. Furthermore, the fuel consumption and carbon dioxide emission of this system have been encountered with reduction of 31.83% and 38.44% in comparison with conventional energy systems for buildings of the same conditions. Highlights • A new arrangement of a trigeneration system driven by Stirling engine for building applications was proposed. • A non-ideal adiabatic model with consideration of the thermal and fractional losses of engine was used. • The appropriate working conditions of the trigeneration system were suggested. • Fuel consumption and carbon dioxide emission were reduced compared to conventional systems. [ABSTRACT FROM AUTHOR]

This paper proposes a modified exergoeconomic method based on energy level with reliability considerations to analyze the cost allocations in a biomass trigeneration system. Energy level is introduced to the exeregoeconomic method to agree with the principle of high energy level with high cost. The system reliability and availability using the combination of state-space and the Markov method is incorporated in the exergoeconomic method to analyze the cost changes for three products in the trigeneration system. The cost influences of failure rate, repair rate, biomass cost and annual operation time are examined to reveal the cost variations with reliability considerations. The cost allocation and sensitivity analysis are presented in a case study. The results indicate that the failure and repair rates of the gasification system largely influences the cost of products from the electricity generation system and the cooling system. The specific exergy cost of the three products with reliability consideration increases approximately 16%. The reduced operation uptime due to component's or subsystem's failure is the key parameter to decrease the revenue at the certain investment and increase the risk cost. [ABSTRACT FROM AUTHOR]

Trigeneration systems based on renewable energies are useful solutions to provide heat, cooling and electricity in buildings and industries. According to the International Energy Agency, more than 30% of the world population has a profile demand requiring heating and cooling and this percentage is above 70% in many developed countries. This paper experimentally evaluates the energy performance of a trigeneration system based on a solar PVT-assisted heat pump installed in an industrial building. The heat pump is a vapor compression air-to-water type, with a nominal capacity of 16 and 10.5 kW in heating and cooling respectively. The PVT solar field consists of unglazed PVT collectors with a total area of 13.6 m2. Results indicate that this type of system is effective to provide heat, cooling and electricity, using mainly solar energy. The PVT solar thermal fraction is significant to provide domestic hot water, but it is less representative in heating production. On the other hand, solar electrical production gets high representative contributions to feed the heat pump compressor. Different performance indicators were calculated to evaluate the system performance. Besides, a comparison with a reference system, that uses a PV instead of a PVT technology, was also evaluated. [ABSTRACT FROM AUTHOR]

• A novel trigeneration process for crude helium, liquefied natural gas, and methanol production was proposed. • The application of WRU provided the feasibility of producing more methanol through a separation process from vapor streams. • Comprehensive energy, exergy, economic, and environmental analyses were performed for feasibility evaluation. • According to the results, the total energy and exergy efficiencies were obtained to be 94.38% and 93.4%. • The net present value of the designed scheme was estimated to be 364.36 M$. This study suggested a novel integrated trigeneration system for crude helium (He), liquefied natural gas, and methanol production. This proposed system consisted of a cryogenic-based helium recovery unit from natural gas, a syngas synthesis unit by hybrid reforming, a methanol synthesis unit, and a sour water recovery unit. Comprehensive energy, exergy, environmental, and economic analyses were performed to assess the system's performance. Based on the results, the crude helium, liquefied natural gas, and methanol production rates were obtained to be 4105 k g / h , 3594000 k g / h , and 707800 k g / h , respectively. These production rates provided 93.4 % and 94.38 % overall exergy and energy efficiencies. Also, over 60 % of the total exergy destruction occurred in reactors (R1-R4). The application of sour water recovery supplied 85.66 % of the reforming and methanol synthesis process. Regarding environmental analysis, 94 % of the CO 2 emission was due to the indirect mode, and the rate of the CO 2 emission was estimated to be 0.164 k g C O 2 / k g p r o d s . Finally, the economic analysis indicated that the total annual production costs were about 440.16 M$ and 0.13 U S D / k g. Therefore, the net present value of the designed scheme was estimated to be 364.36 M$. [ABSTRACT FROM AUTHOR]

Research and development on integrated energy systems such as cogeneration and trigeneration to improve the efficiency of thermal energy as well as fuel utilisation have been a key focus of attention by researchers. Total Site Utility Integration is an established methodology for the synergy and integration of utility recovery among multiple processes. However, Total Site Cooling, Heating and Power (TSCHP) integration methods involving trigeneration systems for industrial plants have been much less emphasised. This paper proposes a novel methodology for developing an insight-based numerical Pinch Analysis technique to simultaneously target the minimum cooling, heating and power requirements for a total site energy system. It enables the design of an integrated centralised trigeneration system involving several industrial sites generating the same utilities. The new method is called the Trigeneration System Cascade Analysis (TriGenSCA). The procedure for TriGenSCA involves data extraction, constructions of a Problem Table Algorithm (PTA), Multiple Utility Problem Table Algorithm (MU PTA), Total Site Problem Table Algorithm (TS PTA) and estimation of energy sources by a trigeneration system followed by construction of TriGenSCA, Trigeneration Storage Cascade Table (TriGenSCT) and construction of a Total Site Utility Distribution (TSUD) Table. The TriGenSCA tool is vital for users to determine the optimal size of utilities for generating power, heating and cooling in a trigeneration power plant. Based on the case study, the base fuel source for power, heating and cooling is nuclear energy with a demand load of 72 GWh/d supplied by 10.8 t of Uranium-235. Comparison between conventional PWR producing power, heating and cooling seperately, and trigeneration PWR system with and without integration have been made. The results prove that PWR as a trigeneration system is the most cost-effective, enabling 28% and 17% energy savings as compared to conventional PWR producing power, heating and cooling separately.

A solar-assisted trigeneration system for producing electricity, cooling, and heating simultaneously is an alternative scheme to improve energy efficiency and boost renewable energy. This paper proposes a phosphoric acid fuel cell trigeneration system integrated with methanol and steam reforming assisted by solar thermal energy. The trigeneration system consists of a solar heat collection subsystem, methanol steam reforming subsystem, fuel cell power generation subsystem, and recovered heat utilization subsystem. Their respective thermodynamic models are constructed to simulate the system input/output characteristics, and energy and exergy efficiencies are employed to evaluate the system thermodynamic performances. The contribution of solar energy to the system is analyzed using solar energy/exergy share. Through the simulation and analysis of methanol and steam reforming reactions, the optimal reaction pressure, temperature, and methanol to water ratio are obtained to improve the flow rate and content of produced hydrogen. The thermodynamic simulations of the trigeneration system show that the system energy efficiencies at the summer and winter design work conditions are 73.7% and 51.7%, while its exergy efficiencies are 18.8% and 26.1%, respectively. When the solar radiation intensity is different from the design work condition, the total energy and exergy efficiencies in winter decrease approximately by 4.7% and 2.2%, respectively, due to the decrease in solar heat collection efficiency. This proposed novel trigeneration system complemented by solar heat energy and methanol chemical energy is favorable for improving the energy level of low-temperature solar energy and promoting the application of renewable energy. [ABSTRACT FROM AUTHOR]

The study and the optimization of single devices, plants and integrated systems among producers and users, must be performed considering the possibility of energy storage and conversion among different forms of energy in order to reach the best overall energetic and environmental performance. Small CHP distributed plants are particularly interested in these challenges, both in stand-alone and grid-connected configurations. In this paper, the optimal design and management strategy of a trigeneration system composed by a PV plant, a diesel CHP engine, a reversible heat pump and a boiler is studied. The possibility of hybrid storage by means of a hot and a cold reservoirs, a pack of batteries, and a pumped hydro energy storage is investigated. By applying a model based on the Particle Swarm Optimization, the devices size and the operation strategy are simultaneously optimized. The most suitable devices' hourly-based operation profile and the best management strategy of the energy storages are predicted. The minimization of the overall costs is the problem's optimization target, while the main constrain is the fulfillment of the users' request of electricity, heat, cooling and drinking water. [ABSTRACT FROM AUTHOR]

In the present article attempt is made to develop an exergoeconomic optimization model to integrate solar energy into trigeneration system producing electricity, heating and cooling according to the exergetic, economic and environmental targets. The results show that by selecting final optimum solution for the trigeneration system, the unit cost of products reduced by 11.5% and exergy efficiency increased from 44.38% in the base case to 56.07% in the optimum case. The application of optimization process shows that exergoeconomic analysis improved significantly the total performance of the trigeneration system in a way that fuel cost, exergy destruction cost and environmental impacts (CO 2 emissions cost) are reduced by 24.17%, 38.87% and 24.17%. Finally, sensitivity analysis is carried out to examine the effect of changes in the trigeneration Pareto optimal solutions and the unit cost of products to the important economic parameters, such as interest rate, fuel cost, system operation period, and construction period. [ABSTRACT FROM AUTHOR]

A hybrid solar-assisted trigeneration system is analyzed in this paper. The system is composed of a 20 m² solar field of evacuated tube collectors, a natural gas fired micro combined heat and power system delivering 12.5 kW of thermal power, an absorption heat pump (AHP) with a nominal cooling power of 17.6 kW, two storage tanks (hot and cold) and an electric auxiliary heater (AH). The plant satisfies the energy demand of an office building located in Naples (Southern Italy). The electric energy of the cogenerator is used to meet the load and auxiliaries electric demand; the interactions with the grid are considered in cases of excess or over requests. This hybrid solution is interesting for buildings located in cities or historical centers with limited usable roof surface to install a conventional solar heating and cooling (SHC) system able to achieve high solar fraction (SF). The results of dynamic simulation show that a tilt angle of 30° maximizes the SF of the system on annual basis achieving about 53.5%. The influence on the performance of proposed system of the hot water storage tank (HST) characteristics (volume, insulation) is also studied. It is highlighted that the SF improves when better insulated and bigger HSTs are considered. A maximum SF of about 58.2% is obtained with a 2000 L storage, whereas the lower thermal losses take place with a better insulated 1000 L tank. [ABSTRACT FROM AUTHOR]

The trigeneration systems are widely used owing to high efficiency, low greenhouse gas emission and high reliability. Especially, those trigeneration systems taking renewable energy as primary input are paid more and more attention. This paper presents a feasible trigeneration system, which realizes biomass and solar energy integrating effective utilization according to energy cascade utilization and energy level upgrading of chemical reaction principle. In the proposed system, the solar energy with mid-and-low temperature converted to the chemical energy of bio-gas through gasification process, then the bio-gas will be taken as the fuel for internal combustion engine (ICE) to generate electricity. The jacket water as a byproduct generated from ICE is utilized in a liquid desiccant unit for providing desiccant capacity. The flue gas is transported into an absorption chiller and heat exchanger consequently, supplying chilled water and domestic hot water. The thermodynamic performance of the trigeneration system was investigated by the help of Aspen plus. The results indicate that the overall energy efficiency and the electrical efficiency of the proposed system in case study are 77.4% and 17.8%, respectively. The introduction of solar energy decreases the consumption of biomass, and the solar thermal energy input fraction is 8.6%. In addition, the primary energy saving ratio and annual total cost saving ratio compared with the separated generation system are 16.7% and 25.9%, respectively. [ABSTRACT FROM AUTHOR]

Chemical-looping combustion (CLC) that occurs without reacting air and fuel is a promising technology for achieving CO 2 capture with a low energy penalty and without additional energy consumption. This paper proposed a solar-hybrid trigeneration system based on methane CLC to produce electricity, chilled water for cooling, and hot water. CaS and CaSO 4 are the cycle materials of the CLC, and the reduction reaction in the CLC is driven by solar thermal energy. The thermodynamic performances of the new CLC trigeneration system, including energy and exergy efficiencies, are analyzed and compared on the basis of design conditions and variable parameters, respectively. The results indicate that the optimal solar heat collection temperature is approximately 900 °C, the pressure ratio of the air compressor is 20, and the energy and exergy efficiencies reach 67% and 55%, respectively. The output ratios of the three products vary with the solar collection temperature and pressure ratio. Meanwhile, the net SCLC-to-exergy efficiency and the saving rate of the solar collection area are expected to be 24% and 63%, respectively. [ABSTRACT FROM AUTHOR]

Heat recovery boosting applications, especially polygeneration, provide an efficacious effort toward sustainable energy supply, air pollution control, and financial saving. Among new technologies, solid oxide fuel cells are able to effectively operate benefiting from high-temperature syngas output to boost the applicability of combined cycles. Respecting this manner and embracing a renewable energy resource, i.e., biomass fuel, a biomass Gasifier-Solid oxide fuel cell is devised in this paper; its waste heat is recovered by a doable-flash binary geothermal power plant for better operation. Accordingly, a thermal-based desalination, namely humidification dehumidification desalination, and a domestic water heater are joint to the geothermal cycle resulting in a novel trigeneration application. The possibility is measured by thermodynamic, environmental and exergoeconomic tools; a comprehensive sensitivity analysis is applied together with a multi-objective grey wolf optimization in three different optimization scenarios. Considering eight decision variables for the sensitivity analysis and optimization, the optimization scenarios comprise exergetic efficiency/sum unit cost of products, exergetic efficiency/levelized total emission, and exergetic efficiency/hot water production. Here, the last scenario possesses the best optimum exergetic efficiency of 64.49%; the optimum sum unit cost of product, levelized total emission, and heating production are forecasted at 4.94 $/GJ, 0.124 ton/MWh, and 6549.77 kW, respectively. • A novel power, heating, and freshwater trigeneration system is proposed. • Geothermal and biomass energy sources are used to improve system performance. • Thermodynamic, exergoeconomic, and environmental analyses are performed. • Performing multi-objective grey wolf optimization in various optimization scenarios. • The optimum exergetic efficiency and SUCP of 64.49% and 4.94 $/GJ are obtained. [ABSTRACT FROM AUTHOR]

This study investigates the effect of employment of different operation strategies on the economic and environmental performance of a micro gas turbine trigeneration system (MGT-TGS). The MGT-TGS covers power, heating and cooling load of a selected building in a tropical region. The prime movers used were MGTs with electrical output capacity of 30 kW and 65 kW. Four operation strategies; Power-Match, Heat-Match, Mix-Match, and Base-Load were examined. The Net Present Value and Emissions Reduction Index throughout the life cycle of the MGTs were calculated. It was found that MGT-TGS can only generate positive NPV (Net Present Value) at the end of 25 years life time under unsubsidized electricity price. Mix-Match and Power-Match operation strategies can generate positive NPV because the systems can generate more electricity. However, these operation strategies cannot reduce emissions especially CO 2 and CO when they were compared to a CCGT (Combined Cycle Gas Turbine). Base-Load is the only operation strategy that can reduce all emissions even when it is compared to a CCGT. When the economic and environmental performance is fairly considered using CPERI (Cost Per Emissions Reduction Index), Mix-Match is the optimum solution because it can generate CPERI of US$16.0–92,407, based on NPV. [ABSTRACT FROM AUTHOR]