Exergetic Efficiency Of System Research Articles

Advanced Exergy-Based Optimization of a Polygeneration System with CO2 as Working Fluid.

Using polygeneration systems is one of the most cost-effective ways for energy efficiency improvement, which secures sustainable energy development and reduces environmental impacts. This paper investigates a polygeneration system powered by low- to medium-grade waste heat and using CO2 as a working fluid to simultaneously produce electric power, refrigeration, and heating capacities. The system is simulated in Aspen HYSYS® and evaluated by applying advanced exergy-based methods. With the split of exergy destruction and investment cost into avoidable and unavoidable parts, the avoidable part reveals the real improvement potential and priority of each component. Subsequently, an exergoeconomic graphical optimization is implemented at the component level to improve the system performance further. Optimization results and an engineering solution considering technical limitations are proposed. Compared to the base case, the system exergetic efficiency was improved by 15.4% and the average product cost was reduced by 7.1%; while the engineering solution shows an increase of 11.3% in system exergetic efficiency and a decrease of 8.5% in the average product cost.

Exergy analysis of a steam power station in a sulfuric acid plant

This study presents energy and exergy analyses of a Steam Power station of a sulfuric acid plant. A heat recovery system is implemented in the plant to recover waste heat from an exothermic chemical reaction of the sulfuric acid production process. This research aims to analyze system components to determine where energy losses are. A mathematical model was developed using the EES software to perform the calculations. Exergy analysis is computed for real ranges of the main operating parameters. It was found that the key sources of exergy destruction are the waste heat boiler 41 %, followed by the heaters 24.7 % then the steam turbine 18.6 %, and the condenser 13.8 % of the total exergy destruction. The 2nd law efficiency obtained for the waste heat boiler, the steam turbine, and the condenser is 80 %, 82 %, and 37.4 % respectively, while the overall plant exergy efficiency is 68.7 %. The effect of varying different parameters such as reference environmental temperature on main plant components is investigated. The effect of increasing steam inlet temperature, pressure, and mass flow rate on plant exergetic efficiency and exergy destruction is also presented. Results showed that lowering condenser vacuum pressure leads to a 7 % improvement in overall system exergetic efficiency.

Investigations on a 2.2 K five-stage Stirling-type pulse tube cryocooler. Part A: Theoretical analyses and modeling

This paper conducts systematic theoretical analyses and modeling of a five-stage Stirling-type pulse tube cryocooler (SPTC) which is expected to directly reach a temperature of around 2 K and also to simultaneously achieve the cooling capacities at five temperatures varying from 2.2 K to 80 K for multiple uses. At the fourth stage it uses an active phase compressor (APC) to obtain the optimal phase relationship at the low temperatures below 12 K. A further improved electrical circuit analogy (ECA) model with the APC is developed to investigate the phase characteristics, loss mechanisms, and cooling performance of the last two stages. The structural design of the five-stage SPTC is described, in which a waveform synthesis method based on the impedance and phase analysis is proposed to clarify the effects of APC parameters on the pressure and flow in the regenerators of the last two stages. The impedance and dimensional parameters of both stages are optimized according to the system exergetic efficiency. The simulation results indicate that, with He-3, the system exergetic efficiency of the last two stages is expected to reach 2.39 %. It also indicates a five-stage SPTC alone has potential of reaching 2.2 K with simultaneously having the cooling capacities at five temperatures.

Investigations on a 2.2 K five-stage stirling-type pulse tube cryocooler. Part B: Experimental verifications

In this part, a five-stage Stirling-type pulse tube cryocooler (SPTC) is worked out to verify the theoretical analyses conducted in Part A. The experimental setup is described in detail, and the operating frequency, charge pressure and input electric power of the last two stages are optimized with He-3. Relevant experiments are also conducted with He-4 for comparison. The experimental results show that a no-load temperature of 2.28 K is reached with He-3, and the cooling capacities of 2.5 W at 80 K, 0.15 W at 30 K, 0.05 W at 12 K, 16.9 mW at 6 K, and 12.2 mW at 3.5 K are simultaneously achieved, respectively, with a total system exergetic efficiency of 2.25 %. Satisfactory agreements are observed between theoretical and experimental studies.

Design, 3E scrutiny, and multi-criteria optimization of a trigeneration plant centered on geothermal and solar energy, using PTC and flash binary cycle

A hybrid solar-geothermal power plant for electricity, heating, and cooling is provided in this paper. A flash-binary geothermal cycle, parabolic trough solar collectors, auxiliary heater, single effect LiBr-water absorption chiller, and heat exchangers are all part of the planned integrated power plant. The plant provides steady electrical power as well as the necessary heating and cooling for the yeast industry. The solar-geothermal power plant's energetic and exergetic efficiencies for the proposed system under steady-state conditions with constant irradiation are 10.78 percent and 23.1 percent, respectively. The auxiliary heater is found to function in 85 percent of the year due to the inability of solar energy to increase the fluid temperature to the necessary amount throughout several periods of the year. The impacts of different performance factors on the system's exergetic efficiency and overall cost rate are also evaluated using parametric analysis. It was discovered that parameters such as the flash separator's inlet pressure and temperature, the pinch point temperature difference in the heat recovery steam generator (HRSG), and the geofluid outlet temperature in the heat exchanger 1 (HX1) have a significant impact on the system's exergetic efficiency and total cost rate. Furthermore, the effect of variations in sunbeam irradiance on assessment parameters is examined. In constant heat input to the cycle, increasing beam irradiance results in increased total exergy efficiency and a lower overall cost rate of the system. By raising the sunbeam irradiance, the proportion of the auxiliary heater in the plant's energy supply and the mass flow rate of the fuel would be reduced. Also, the optimization findings show that the exergy efficiency of 33.8 percent might be attained under ideal operating circumstances.

Comprehensive performance exploration of a novel pumped-hydro based compressed air energy storage system with high energy storage density

A compressed air energy storage system is the key issue to facilitating the transformation of intermittent and fluctuant renewable energy sources into stable and high-quality power. The improvement of compression/expansion efficiency during operation processes is the first challenge faced by the compressed air energy storage system. Therefore, a novel pumped-hydro based compressed air energy storage system characterized by the advantages of high energy storage density and utilization efficiency is proposed in this study. To perform a comprehensive investigation on the system, the locations and magnitudes of irreversible sources within the system are estimated through the conventional exergy method, and the interactions among components and realistic potential for system performance improvement are identified by the advanced exergy method. The results indicate that the interactions among components are complex but not very significant since the endogenous exergy destruction is larger than the exogenous exergy destruction for all components within the system. Furthermore, the conventional exergy analysis reveals that the expander, compressor1, and pump are the most important components, accounting for 25.99%, 22.55%, and 15.34% of the total exergy destruction, respectively. Nevertheless, advanced exergy analysis recommends that the hydraulic turbine, pump, and expander have the optimization priorities since they share 28.61%, 27.72%, and 10.07% of the total endogenous avoidable exergy destruction. Finally, the overall system exergetic efficiency achieves a higher value of 18.49% under unavoidable conditions than that under real conditions.

Multi-aspect assessment and multi-objective optimization of sustainable power, heating, and cooling tri-generation system driven by experimentally-produced biodiesels

This paper proposes a tri-generation system based on a diesel engine. An organic Rankine cycle and an ejector refrigerant cycle are employed to recover the diesel engine waste energy and produce cooling and more power. Also, a heat exchanger is installed to supply the heating demand. The mass, energy, exergy, exergoeconomic, and environmental analyses are applied to evaluate the proposed system's performance. Twelve biodiesels and pure Diesel energetic, exergetic, exergoeconomic, and environmental performances are compared to select a proper fuel for the designed system. Furthermore, the system's optimum state is evaluated through the exergy-economic assessment. In this regard, the Canola B20 is chosen as the best fuel for the designed system, which provides 7468 kW net power with 37.96% exergetic efficiency, 1.611 sustainability, and 1.635 environmental impact indexes at the base state. The engine exergetic efficiency is influenced by the engine load, while the total exergetic efficiency is affected by the engine speed. Besides, the ORC flow rate as the subsystem variable criteria has the highest effect on the system performance. Also, the system exergetic efficiency and unit product cost are obtained to be 37.96% and 11.196 $/GJ at the optimum state, respectively.

Comprehensive techno-economic investigation of biomass gasification and nanomaterial based SOFC/SOEC hydrogen production system

This work handled the hydrogen generation by steam-based sawdust gasification procedure. Furthermore, it examined hydrogen generation requirements through conducting thorough parametric examinations concerning parameters that influence hydrogen generation efficiency. Through the integration of the hydrogen generation unit in the newly installed plant, the amount of generated hydrogen had been studied by integrating the solid oxide fuel cell and solid oxide electrolysis cell and relying on the steam gasification of sawdust as biomass. To assess the performance of this new system, a thorough investigation employing thermodynamic and thermoeconomic analyses, and parametric assessments are conducted. Outcomes documented that the maximum destroyed exergy happened in the integrated nanomaterial-based SOFC/SOEC subsystem. The system's exergetic efficiency including hydrogen efficiency rose from 64 to 77%. Also, relying on the thermoeconomic model, the yield of the system's net generated hydrogen improved by about 3%, reducing the unit cost of hydrogen to 0.21 $/kWh from 0.26 $/kWh.

Thermodynamic effect of RNA virus infection on the human cardiovascular system.

In this work, analysis of cardiovascular system under the influence of RNA virus infection has been performed from a thermodynamic perspective. An exergetic efficiency of the system has been defined for this purpose. Results show that except for asymptomatic case, the exergetic efficiency reduces as the viral load goes up. Dynamics of viral growth along with change in efficiency is examined under different parameters such as virus production rate, infectivity rate and cell death rate. Results show that the drop in the exergetic efficiency of cardiovascular system under viral infection can be up to about 20%. Under infection, the exergy requirement of the lungs increases significantly as the work rate required by lungs increase by up to 240%.

FACTOR ANALYSIS OF THE THERMAL SCHEME OF CHP WITH SUPER CRITICAL STEAM CYCLE ON THE BASIS OF EXERGY METHOD

The most promising direction of CHP modernization is the introduction of power units on supercritical steam parameters. Increasing steam parameters is one of the most effective ways to increase the efficiency of a CHP plant. Thus, the development of the concept of thermal schemes turbines for supercritical steam parameters, taking into account the characteristics of their operation at the existing CHP Ukraine is an actual scientific problem. The solution to this problem will make it possible to replace or modernize the power generating equipment that has exhausted its resource with modern power units that meet world economic and environmental standards. The method of exergy analysis is adapted to the study of thermal schemes of CHP plants with supercritical steam cycle. As an example of application of a method the exergy analysis of the power plant working on the one-stage thermal scheme is carried out. Within the framework of the proposed method, a thermodynamic and topology-exergetic model of the power plant is created. Based on the topology-exergetic model the indicators of thermodynamic efficiency of the power plant operating on supercritical parameters of steam are determined. It is proposed to apply the theory of experiment planning in exergy analysis of the thermal circuit of a CHP. With the involvement of this theory, a multifactor numerical experiment was conducted to determine the impact on the exergetic efficiency of the thermal scheme of CHP of the main determining variable factors, such as adiabatic and thermal efficiency of the plant, as well as the operating parameters. The generalized equation of functional interrelation of exergetic efficiency of system and exergetic efficiency of elements of thermal scheme of CHP is received. The proposed equation can be used as a tool for further training of neural networks and their application both in the design and in the diagnosis of energy efficiency of CHP. According to the results of the factor analysis, a rather high conservatism of the considered one-stage scheme of CHP to the change of the varied parameters was revealed. This indicates the presence of more rigid structural links between the elements, which is generally a positive aspect of the reconstruction.

Advanced exergy analysis of a Joule-Brayton pumped thermal electricity storage system with liquid-phase storage

Pumped thermal electricity storage is a thermo-mechanical energy storage technology that has emerged as a promising option for large-scale (grid) storage because of its lack of geographical restrictions and relatively low capital costs. This paper focuses on a 10 MW Joule-Brayton pumped thermal electricity storage system with liquid thermal stores and performs detailed conventional and advanced exergy analyses of this system. Results of the conventional exergy analysis on the recuperated system indicate that the expander during discharge is associated with the maximum exergy destruction rate (13%). The advanced exergy analysis further reveals that, amongst the system components studied, the cold heat exchanger during discharge is associated with the highest share (95%) of the avoidable exergy destruction rate, while during charge the same component is associated with the highest share (64%) of the endogenous exergy destruction rate. Thus, the cold heat exchanger offers the largest potential for improvement in the overall system exergetic efficiency. A quantitative analysis of the overall system performance improvement potential of the recuperated system demonstrates that increasing the isentropic efficiency of the compressor and turbine from 85% to 95% significantly increases the modified overall exergetic efficiency from 37% to 57%. Similarly, by increasing the effectiveness and decreasing the pressure loss factor of all heat exchangers, from 0.90 to 0.98 and from 2.5% to 0.5% respectively, the modified overall exergetic efficiency increases from 34% to 54%. The results of exergy analyses provide novel insight into the innovation, research and development of pumped thermal electricity storage technology.

Air-source heat pump performance comparison in different real operational conditions based on advanced exergy and exergoeconomic approach

The use of air-source heat pumps (ASHP) is increasing to meet the energy needs of residential buildings, and manufacturers of equipment have permanently expanded the range of work and improved the efficiency in very adverse outdoor air conditions. However, in the time of a wide range of different technologies, the problem of using ASHP, from a techno-economic point of view, is constantly present. Exergetic efficiency and exergoeconomic cost no longer provide sufficiently reliable information when it is necessary to reduce the investment costs or in-crease the energy/exergetic efficiency of the component/system. This paper presents comparison of ASHP in different operational conditions based on an advanced exergy and exergoeconomic approach. The advanced exergy analysis splits the destruction of exergy for each individual component into avoidable and unavoidable part in order to fully understand the processes. The information of stream costs is used to calculate exergoeconomic variables associated with each system component. Irreversibility in the compressor have the greatest impact on reducing the overall system exergetic efficiency by 46.7% during underfloor heating (UFH) operation and 24.53% during domestic hot water (DHW) operation. Exergy loss reduces exergetic efficiency by 5.72% UFH and 39.74% DHW. High values of exergoeconomic cost for both operating regimes are present in flows 1, 2, 3 and 4 due to high costs of production and relatively small exergy levels. The general recommendation is to set the ASHP to operate with near-optimal capacities in both regimes and then reduce exergy of flows 1, 2, 5, 11, and 13.

The performance assessment of a refrigeration system which exists on a cargo vessel influenced by seawater-intake temperature

The effects of the seawater-intake temperature on the performance of the refrigeration system which exists on a cargo vessel were introduced in this study. The performance of the real refrigeration system was analysed by using both conventional and advanced exergy analyses and exergoeconomic evaluation. First, a parametric study with different seawater-intake temperatures was carried out by applying conventional exergy and advanced exergy analyses to the refrigeration system considered to identify the pinch point components and processes with high irreversibilities. Then, advanced exergy analyses were applied to overcome technological and physical limitations to increase the knowledge about the refrigeration system. The exergetic efficiency of the refrigeration system was calculated based on varying seawater-intake temperature which enters the condenser while other operating parameters are kept constant. Seawater-intake temperatures were selected in terms of regional seawater temperatures which are assumed to be in the vessel route. As a result of the study, it was determined that the hot entry of the seawater into the condenser causes a reduction in the exergetic efficiency of the refrigeration system. The gap between real system exergetic efficiency and the unavoidable cycle exergetic efficiency increased as the pinch point temperature differences increased in the condenser by approximately 16%. Some of the exergy destruction in the refrigeration system components was unavoidable and constrained by technological and physical limitations. Based on the findings in this study, it has been shown that the greatest improvement in the exergetic efficiency of the cooling system can be achieved by improving the condenser and compressor.

Exergetic and integrated exergoeconomic assessments of a hybrid solar-biomass organic Rankine cycle cogeneration plant

This study is aimed at investigating optimization potentials in a conceptual hybrid solar-biomass organic Rankine cycle (ORC) cogeneration plant, through component-based exergy and exergoeconomic analyses. The ORC is rated at 629 kWe, and it is related to a real and operational plant. Exergy balance is established in each system component, from where irreversibility rate in the respective components is obtained. Thus, exergy-based rational efficiency and efficiency defects are computed for each system component. Also, economic performance is assessed at component level, for the entire system, using conventional specific exergy costing (SPECO) approach. The energy quality level of each thermodynamic state is also integrated into SPECO formulations, providing a different way of obtaining unit exergy cost for each stream. This is termed here as integrated exergoeconomic approach. Exergy destruction cost rate, exergoeconomic factor and relative cost difference are used as criteria for exergoeconomic performance evaluation. Furthermore, the level of recoverability of exergy destruction in each of the system components is assessed, in order to identify notable improvement potentials. The evaluation of optimization potentials considers intrinsic irreversibilities in the respective components, which are imposed by the assumptions of systemic and economic constraints, and thus cannot be eliminated. Results showed that system exergetic efficiency amounts to about 11%. Also, cost of producing electricity was obtained as 10.5 c€/kWh and 12.1 c€/kWh, respectively for conventional and integrated exergoeconomic approach. Furthermore, cost of producing warm water was obtained to be lower by about 56% in integrated exergoeconomic approach, relative to the conventional approach. For the whole system, adopting integrated exergoeconomic approach led to reduced loss of investment costs by about 1.5 percent points, relative to the conventional approach.

Preliminary design and part-load performance analysis of a recompression supercritical carbon dioxide cycle combined with a transcritical carbon dioxide cycle

Nuclear energy can be efficiently converted to electrical energy in the supercritical carbon dioxide (sCO2) power system. In this paper, a combined cycle comprising a topping sCO2 cycle and a bottoming transcritical CO2 cycle (tCO2) is investigated. Multi-objective optimization by means of a genetic algorithm is carried out to obtain better thermodynamic and economic performance in the design stage. The methodology for part-load operation of the combined sCO2-tCO2 cycle is proposed and the quantitative performance analysis is conducted for the utilization of nuclear energy. The results indicate that there exists optimal values for the maximum system exergetic efficiency and the minimum total product unit cost. A composite control strategy by adjusting the rotational speed of compressors and the opening of bypass valve is proposed for the topping sCO2 cycle operation from the point of view of both efficiency and operation range. The bottoming tCO2 cycle is well adapt to the changes of parameters in the topping sCO2 cycle and heat sink temperature by using the sliding pressure control strategy. The combined sCO2-tCO2 cycle can operate under 10–100% normalized generator load when the variation scope of heat sink temperature is 5–25 ℃.The corresponding exergetic efficiency of combined sCO2-tCO2 cycle ranges from 24.5% to 65.7%.

Conventional and advanced exergy analysis of an air-cooled type of absorption-ejection refrigeration cycle with R290-mineral oil as the working pair

An absorption-ejection refrigeration cycle used R290-mineral oil mixture is investigated depending on both conventional and advanced exergy analysis. In this cycle, an ejector and an air-cooled type absorber are utilized to improve the exergetic efficiency of the system. The effects of generator temperature, condensing temperature, evaporating temperature, absorber outlet temperature, absorber efficiency, and pressure ratio on system exergetic efficiency have been discussed and compared with a single-effect absorption cycle in this study. Furthermore, the exergy destruction of each component has been calculated and analyzed. Besides, the exergy destruction of the major components are further researched through the advanced exergy analysis. Analytical results show that the absorption-ejection refrigeration cycle has a higher exergetic efficiency and a more extensive working condition range than the single effect absorption cycle and its exergetic efficiency can reach 0.3554. It is proved the R290/mineral oil as absorption refrigeration has great research value. In addition, the vast majority of exergy destruction appears in the generator and absorber, totally above 60%. The optimization of the generator has the highest priority due to its maximum endogenous avoidable exergy destruction. The absorber is in second place and its exergy destruction can be effectively reduced by optimizing other components.

Exergy analysis of the flow process and exergetic optimization of counterflow vortex tubes working with air

Vortex tubes can separate a pressurized gas stream into a cold stream and a hot stream. However, their use is limited by the low efficiency of the device. In this article, the exergy efficiency considering transiting exergy is used to analyze the thermal exergy production and exergy destruction in vortex tubes using a thermodynamic model and experimental data from the literature. The vortex tube exergetic efficiency reaches a maximum (up to 2.88%) for a cold mass fraction around 0.7 when both the hot and the cold outlets are considered as useful. Interestingly, 45% of the available exergy is lost downstream of the vortex tube through pressure losses at this condition. Inside the vortex tube, kinetic exergy destruction represents a great portion of the irreversibilities within the tube. Furthermore, the thermodynamic model is used to maximize the efficiency of a single vortex tube. The optimization process increases the exergetic efficiency of the vortex tube to 4.4%, corresponding to an increase of 53% compared to the best experimental values. Additionally, the analysis demonstrates that increasing the cold outlet pressure increases the vortex tube exergetic efficiency for the same pressure ratio. Finally, the thermodynamic model is used to identify the vortex tubes cascade which better uses a compressed air source at 6 bars. A cold cascade with an ejector is also investigated. Results show that the cascade configuration could benefit from unused pressure from the first tube to increase the system exergetic efficiency.

Dynamic simulation and exergetic optimization of a Concentrating Photovoltaic/ Thermal (CPVT) system

The development of a dynamic, theoretical model suitable for the prediction of the long-term performance of a parabolic-trough Concentrating Photovoltaic/Thermal CPVT system is discussed in the present study. The formulation of the mathematical model and the considered geometrical and operational parameters of the system, such as the characteristics of the employed PV modules and active cooling system are described in detail. The effect of heat capacity is taken into consideration in the thermal balances and thus the model is able to capture the transient behavior of the system. Besides, the model is validated using available experimental data of a manufactured prototype CPVT system. The daily performance of system is predicted for different values of the cooling fluid flow rate and temperature under various environmental conditions. At a second stage, an exergy analysis is conducted in order to point out the effect of the characteristics of the main system sub-components on the exergetic efficiency and exergy output of the CPVT system. It was established that the system exergetic performance is primarily influenced by the optical quality of the parabolic trough and the electrical efficiency of the PV module. Increasing these two factors to achievable values, e.g. ηopt = 0.75 and ηel = 0.25, can yield an increase of the system exergetic efficiency from 12% to 24%.

Exergy analysis and optimization of a combined cooling and power system driven by geothermal energy for ice-making and hydrogen production

This paper investigates a combined cooling and power system driven by geothermal energy for ice-making and hydrogen production. The proposed system combines geothermal flash cycle, Kalina cycle, ammonia-water absorption refrigeration cycle and electrolyser. The geothermal energy can be efficiently converted to storable hydrogen and ice. Based on mathematical model, some key parameters are analyzed to figure out their effect on the exergetic performance. An exergy destruction analysis for all components has been performed to find out the distribution of exergy inefficiency. The system exergetic efficiency is optimized by Jaya algorithm and Genetic algorithm and the optimization results are compared. According to the parametric analysis, the exergy efficiency decreases as the back pressure of steam turbine and the back pressure of ammonia-water turbine increase. The exergy efficiency could increase first and then decline, as flash pressure, ammonia-water turbine inlet pressure and ammonia mass fraction of basic solution increase. The optimization results show that the exergy efficiency reaches 23.59%, 25.06% and 26.25% when the geothermal water temperature is 150 °C, 160 °C and 170 °C. Jaya algorithm has highly precise optimization results.

Exergy and Energy Analysis of Solid Oxide Fuel Cell Fuelled Using Methanol Propane, and Butane

Exergy and Energy analysis used the principle of conservation of mass and energy, in connection with thermodynamics law in designing and analysing of thermal system This Paper focus on Energy and Exergy analysis of Solid Oxide Fuel Cell (SOFC) system by computer simulation. A comprehensive effect of Energy and Exergy analysis on SOFC using Methanol, Propane, and Butane fuel system with the aid of Thermolib simulation toolbox was investigated. From the configurations simulated for the three different fuel sources, the data produced were used for thermodynamic analysis. The result obtained showed that Butane configuration has the highest energy efficiency of 50.3% .while Methanol and Propane system has an energy efficiency of 46.5% and 47.7% respectively. The total energy produced by Methanol, Propane and Butane Fuel System are 273.66 KW, 234.67 and 263.92 kW respectively. While that required are 69.45 KW, 0.062 KW and 4.972 KW respectively. This shows that the highest energy requiring and producing system is the Methanol Fuelled system. The principle of energy conservation was met in all configurations. The Exergy analysis indicated that around equipment such as Reactor, lambda burner and SOFC stack there is a change between the inlet and outlet chemical Exergy. However the chemical Exergy for Pumps, Heat exchangers, compressor and Mixer remains the same because no chemical reaction occurs in them. In addition, equipment such as pump and compressor gives higher Exergetic efficiency than others. In terms of overall loss work, Methanol, Propane, and Butane system are 422.2 KW, 247.7KW, 195.7 KW respectively. The Overall System Exergetic efficiency of the three fuel systems are 44.2%, 49.3%, and 46.7% respectively. This shows that Propane system has the highest Exergetic efficiency and least irreversibility. While Methanol fuel system has the lowest Exergetic efficiency and most irreversibility. Exergy and energy efficiency favours the choice of propane fuel system. This is because Propane is the most Exergy efficiency system.