Exergy Values Research Articles

Effect of coal powder mass‐energy conversion efficiency on oxygen coal ironmaking and parameter optimization

AbstractA new process of prereduction of rotary kiln‐oxygen coal combustion and melting ironmaking was developed. The core is to realize the conversion of mass and energy of pulverized coal through high‐density injection of pulverized coal and high‐density combustion in the molten pool to provide the required energy for the ironmaking process. By calculating the combined energy values of working conditions under different metallization rates (η), gas oxidation degrees (α) and blast oxygen content (μ), the pulverized coal consumption, exergy income, exergy expenditure, four gas exergy values, and process of the process system under different working conditions were analyzed. Exergy using efficiency, quantitatively evaluated the interaction between the mass‐energy conversion efficiency of coal powder and process parameters and used orthogonal analysis to determine the combination of working conditions with the highest energy utilization rate. The results show that increasing the metallization rate, gas oxidation degree, and blasting oxygen content will change the exergy value, and the exergy utilization efficiency will increase with the increase of metallization rate, gas oxidation degree, and blast oxygen content, but the various parts exergy the value does not reach the optimum with the increase of the process operating parameters. After comparing and analyzing the overall working conditions, it can be known that when the charge metallization rate is 70%, the melting furnace gas oxidation degree is 12% and the blast oxygen content is 98%, the rotary kiln‐oxygen coal combustion melting furnace has the best operating conditions and the highest energy utilization efficiency. A mathematical relationship model including metallization rate, gas oxidation degree, blast oxygen content, and process exergy utilization efficiency was established: y = η × 0.1908+α × 0.467227383+μ × 0.137069+0.522508.

Exergoeconomic analysis of zeotropic mixture on the new proposed organic Rankine cycle for energy production from geothermal resources

In this study, the performance of Isobutane/Isopentane (zeotropic mixture) is studied in the new proposed Organic Rankine Cycle (NORC). Operating parameters included temperatures of two series evaporators and regenerative, degree of superheating, and pinch point temperature difference in the first evaporator are optimized with multi-objective functions i.e., exergy as thermodynamic, Specific Investment Cost (SIC) as economic and exergoeconomic as the third objective function that considered exergy and SIC simultaneously. Optimization results for Isobutane/Isopentane indicate that the value of exergy has a sharp decrease when the mole fraction of Isobutane increases to 0.5, and after that, the exergy amount rises significantly and reaches a peak at 54.584% for pure Isobutane. Also, return on investment (ROI) is employed as an economic indicator to get the center of attention in economic proficiency by utilizing Isobutane/Isopentane in NORC configuration according to the exergoeconomic results for fifteen countries as two groups of developed and developing in order to compare profitability all around the world. The results represent that, by the growing of Isobutane mole fraction in Isobutane- Isopentane mixture, ROI indicator is reduced. The maximum and the minimum value of ROI are related to Germany (57.64%) and India (4.09%), respectively.

Experimental investigation of solar cooking system based on evacuated tube solar collector for the preparation of concentrated sugarcane juice used in jaggery making

An experimental investigation of a solar cooking system has been performed for the preparation of concentrated sugarcane juice required in jaggery making. An evacuated tube solar collector has been used as a heat collecting medium. Experiments have been performed on sunny and clear sky days by taking the cooking loads of 1, 1.5 and 2 L of sugarcane juice. To predict the thermal performance of solar cooking system, an exergy-based approach is employed. The obtained results have been compared with the other solar cooking systems considering performance factors like peak exergy power and product of the peak exergy power value with the temperature difference gap. The maximum value of peak exergy power and the product of temperature difference gap with peak exergy output value is observed maximum for the 2 L of cooking load. A percentage increase of 76% and 59% in the value of peak exergy for the presented system is observed with reference to the peak exergy power for the box-type and parabolic trough-type solar cooker design, respectively. Furthermore, 53.3% rise in the time taken is observed for the cooking load of 2 L with respect to 1 L of cooking load. The results from the present study emphasized that evacuated tube-based solar cooking system has the potential to maintain the temperature of sugarcane juice above its boiling point temperature even in low solar intensity hours.

Proposal and comprehensive analysis of an innovative CCP plant based on an internal integration of double flash power system and ejector refrigeration cycle

Utilizing high-efficient systems for cooling and electricity generation from green energy resources is an efficient method of sustainable development. For this aim, an innovative hybrid cycle for simultaneous power and cooling generation is recommended. The presented system is an internal integration of double-flash ejector refrigeration and power systems. First-law and second-law analysis are employed to investigate the feasibility of the system. Besides, a single-objective optimization performed by the implementation of the GA technique. The optimal energy and exergy efficacies are achieved by 72.57% and 27.69%, respectively.Furthermore, a thorough parametric analysis indicated that the energy and exergy efficacies could be optimized according to turbine pressure and ejector pressure. Moreover, it is showed that a higher energy efficacy and cooling capacity is obtainable by augmenting the ejector pressure, evaporator temperature, and compressor pressure ratio. Whereas, the exergy efficacy can be enhanced by increasing condenser #2 pressure. Besides, based on the exergy efficacy of each constituent of the system, the flashing chamber 1 shows the most excellent exergy efficacy among all the constitutes while the highest value of exergy is destroyed within the condenser 1.

Exergoeconomic and environmental analysis of seawater desalination system augmented with nanoparticles and cotton hung pad

In this work, the performance of solar still was enhanced using nanotechnology and cotton hung pad. The cotton hung pad has threads with ends immersed in seawater, hence the capillary property moves the water upward towards the evaporation surface. The cotton hung pad (small layer), and nanoparticles have a significant effect on localizing the heat that speed up the seawater evaporation rate and improve the performance. The Fe3O4, and CuO nanoparticle materials are used and spreaded to the top surface of the cotton pad with different concentrations in the range of 25 g/m2 to 300 g/m2. Also, the exergoeconomic of the desalination system and environmental analysis are investigated. The results showed an enhancement of about 17.55% in the productivity for the modified solar still (MSS) with cotton hung alone compared with the TSS. The configuration of cotton hung pad and nanoparticles with a concentration of 150 g/m2 enhanced the distillate productivity by about 42.3% and 56.6% for Fe3O4 and CuO nanoparticles, respectively compared to TSS. The highest efficiency was about 51%, 45%, 34.5% and 30% for MSS with CuO, MSS with Fe3O4, cotton hung pad only and TSS, respectively. The exergy values showed enhancement of 103% for MSS with CuO compared to TSS. The economic analysis of different modifications indicated that the cost per liter of fresh water was 0.018 $, 0.016 $, and 0.015 $ for MSS with cotton pad and Fe3O4; cotton pad and CuO; and cotton pad only, respectively while the cost for TSS was 0.0189 US$. Furthermore, the exergoeconomic and environmental analysis of enhanced solar stills showed that these systems are cost-effective and helpful in cutting down carbon footprint by mitigation of CO2. Overall, integrating nanoparticles with cotton hung pads were proved to be very effective and promising from economic, environmental, and exergy point of views.

Exergy-based Control of a Dwelling Ventilation System with Heat Recovery

On the base of exergy-based approach it is shownthat for the ventilation systems there are operating modes forwhich heat recovery increases exergy of fuel expended to providethe ventilation air compared to cases without bringing anyrecovery of heat and additional power consumption to drive theair flow by the fans. For the specified system, in case of switchingventilation unit to the operation mode of lower values of spentfuel exergy it is possible to provide annual saving from 5 to 15 %of the primary energy sources.

Energy and exergy analysis of wavy plate solar air collector using a novel hybrid expert system

In the present work, energy and exergy analysis of wavy plate solar air collector (WPSAC) using a novel hybrid expert system is presented. Sugeno-based subtractive clustering method is used for extraction of cluster centers while multi-criteria ratio analysis is used for optimization and prediction of WPSAC parameter. Experimentation (270 trails) on WPSAC has been performed by varying the mass flow rate of air (m), collector tilt angles (θ), solar radiation (Q), inlet temperature (T). Output parameters, namely effective efficiency (ηeff), exergetic efficiency (ηII), rise in bed temperature (∆Tbed) and mitigation of CO2 emission, are evaluated. The results indicate that at m = 0.00785 kg/s, θ = 45°, Q = 770 W/m2 and T = 25 °C the optimum values of energy, exergy and carbon credit for WPSAC are obtained. The accuracy of prediction is found to be ≈ 98.1%. The maximum ηeff, ηII, ∆Tbed and CO2 for WPSAC are obtained as 37.22%, 11.58%, 62 °C and 0.0009 tons, respectively.

The thermodynamic rarity concept: A systematic review

Abstract The concept of thermodynamic rarity allows the assessment of the exergy needed to extract metals from common ores considering that mineral reserves have a significant exergy value. Estimates show that the reserves of some rare minerals may be exhausted in the next decades; this will cause a severe abiotic depletion that will make the production of certain commodities unfeasible and result in supply risks. This work presents the main scientific contributions to the evolution of the thermodynamic rarity concept, which began with the application of exergy analysis to the environmental-economic characterization of the minerals industry. The methodology used in this work is a longitudinal systematic review, considering the “research thematic area” and its subdomains. The search was performed in two large databases of scientific documents, Scopus and Web of Science. The results present the quantitative evolution of the main publications as well as a bibliometric analysis and a qualitative characterization of the contents of the main articles. The main period of this review was from 1983 to 2018, and it included 630 publications. The three main sets of keywords detected were a) “theory-of-exergetic-cost”; b) “exergy-replacement-cost”; and c) “thermodynamic-rarity”. The concepts that evolved to the idea of thermodynamic rarity during the period analyzed in the study are a) the theory of the Exergy Cost, suggested in 1986; b) the Concentration Exergy of minerals, elaborated in 2008; c) the Concentration Exergy Cost, of 2008; d) Thanatia, developed between 2008 and 2013; and lastly, e) the Exergy Replacement Cost (ERC), developed between 2008 and 2013, which represents the exergy needed to concentrate a mineral from the Thanatia state to the average concentration in a mine (mine state). The concept of Thermodynamic Rarity was published in a book in 2014 and in an article in 2015. It consists of the ERC plus the exergy needed to convert ore from the mine into a commodity. The thermodynamic rarity concept was used in 2017 in the proposition of the “Thermodynamic Criticality” and in 2018 as a method to assess the monetary losses caused by the inability to recover metals used in small amounts in vehicle recycling. In addition, in 2018 thermodynamic rarity was used to suggest specific recommendations in ecodesing.

Application of LSSVM-PSO algorithm as a novel tool to predict standard molar chemical exergy for organic materials

ABSTRACTIn the different chemical processes, determination of equilibrium state has great importance. The chemical exergy as one of indictor of chemical stability can be used for this purpose. Due to this fact, in the present work a novel and accurate Least squares support vector machine (LSSVM) algorithm optimized by Particle Swarm optimization was used to predict standard molar chemical exergy of pure organic substances as function of their structures. The predicted standard molar chemical exergy values were compared with the extracted experimental data from literature in the statistical and graphical manners. The coefficients of determination for training and testing phases were determined as 0.9886 and 0.9928 respectively. The determined indexes and graphical analyses expressed the high degree of accuracy of LSSVM in estimation chemical exergy so the LSSVM algorithm can be used as an accurate predictive tool in thermodynamics of different processes.

EXERGY ANALYSIS ON THERMAL POWER PLANT PT. MAKASSAR TENE USING CYCLE-TEMPO 5

Analyzing exergy on the power plant generating system specially at PLTU, efficient utilization of energy resources can be obtained particularly since it leads efforts to reduce energy waste that already exists.The purposes of this research are to get the Thermal Power Plant system modeling of PT. Makassar Tene, to get the value of modeled exergy power plant system, to get exergy losses, to get the amount exergy efficiency and to get the cost of exergy losses.The research method was firstly, designing the Power Plant generating systems PT. Makassar Tene using Cycle-Tempo 5 as thermodynamic analysis tool. Results of calculations were then used to calculate the exergy profile.Exergy values analyzed on a system modeled Power Plant consists of turbine components, condensers and pump. Boilers are not included in the analysis because of the input device is not contained and the mass flow rate of the boiler occurs steady state in which the state of the same process with the state of the environment so that there is no exergy difference that can be utilized.The highest exergy losses based on the modelling was on the turbine components that was 10201.50 kW. This was due to the change in the vapor phase into the liquid phase contained in the component before and after leaving the turbine components. While the lowest exergy losses was on the pump component, that was 437.18 kW.The higher the efficiency value of a component, the better its performance is. The highest efficiency value of exergy that was 51.43% contained on the turbine components. While the lowest efficiency value of exergy was 0%.

QSPR based ANFIS model for predicting standard molar chemical exergy of organic materials

Prediction of standard molar chemical exergy value for organic compounds is investigated using a quantitative structure-property relationship (QSPR) model combined with adaptive neuro-fuzzy inference system (ANFIS) strategy. Particle swarm optimization (PSO) method is also implemented to determine the optimal ANFIS structure. The proposed model uses three constitutional descriptors in model development’s procedure. The QSPR-ANFIS model represents a great performance in prediction of the standard molar chemical exergy values with 0.9999, 44548, and 1.49 values for R2, RMSE, and %AARD, respectively.

Determination of Energy and Exergy of Syngas Produced from Air-steam Gasification of Wheat Straw in a Dual Distributer Fluidized Bed Gasifier

The energy and exergy of syngas produced from air-steam gasification of wheat straw in a dual-distributor fluidized bed gasifier under different operating conditions were evaluated. Three fluidization velocities (0.35, 0.40 and 0.45 m/s), 3 steam flow rates (0.20, 0.25 and 0.30 kg/min) and 3 biomass: steam ratios (3.00, 4.00 and 5.00 kg/kg) were investigated. The energy values of CO, H2, N2, CO2, CH4, C2H4 and C2H6 varied within the ranges of 1627.09-4646.60, 1543.30-2896.11, 274.75-1742.86, 82.03-574.24, 3225.39-4931.40, 1493.35-3777.44 and 892.74-2319.72 kJ/kg fuel, respectively. The overall energy distribution was (CH4 & CO & C2H4 & H2)>C2H6>(N2 & CO2). The results showed that when the fluidization velocity (FV) was increased from 0.35 m/s to 0.45 m/s (28.57%), the total energy of syngas increased by 1.16-28.59% depending on the steam flow rate (SFR} and biomass: steam ratio (B:S) used. Increasing the SFR from 0.20 kg/min to 0.30 kg/min (50.00%) decreased the total energy of syngas by 27.23-62.35% depending on the FV and B:S used. Increasing the B:S from 3.00 kg/kg to 5.00 kg/kg (66.67%) decreased the total energy of syngas by 11.86-37.33% depending on the FV and SFR used. The exergy values of CO, H2, N2, CO2, CH4, C2H4 and C2H6 were in the ranges of 1486.70-4224.40, 1183.82-2209.00, 60.26-677.26, 54.02-452.97, 2913.74-4448.38, 1404.76-3541.76 and 833.00-2156.42 kJ/kg fuel, respectively. The overall exergy distribution was (CH4 & CO)>(C2H4 & H2 & C2H6)>(N2 &CO2). When the FV was increased from 0.35 to 0.45 m/s(28.57%), the total exergy of syngas increased by 1.45-26.93% depending on the SFR and B:S used. Increasing the SFR from 0.20 kg/min to 0.30 kg/min (50.00%) decreased the total exergy of syngas by 26.78-63.26% depending on the FV and B:S used. Increasing the B:S from 3.00 kg/kg to 5.00 kg/kg (66.67%) decreased the total exergy of syngas by 10.32-36.07% depending on the FV and SFR used. The effect of SFR on the total energy and total exergy of syngas was the highest, followed by B:S and FV. The highest energy (20004.54 kJ/kg fuel) and exergy (16886.06 kJ/kg fuel) of syngas were obtained at the FV of 0.45 m/s, the SFR of 0.20 kg/min and the B:S of 3.00 kg/kg.

Performance, emission, energy, and exergy analysis of CI engine using Kaner seed pyrolysis oil blended diesel

AbstractThis work reports the engine performance, emission parameters, and energy‐exergy characteristics of a twin cylinder four‐stroke CI engine fueled with Diesel blended Kaner seed pyrolysis oil (KSPO). KSPO is obtained by the thermal pyrolysis of Kaner (Thevetia peruviana) seed at 600°C in a batch reactor and mixed with diesel in the ratio of 5, 10, 15, and 20%, to use in the engine. Brake thermal efficiency is marginally higher and brake specific fuel consumption is comparatively lower for KSPO‐diesel blend as compared to pure diesel fuel operation. Low carbon monoxide emission and high hydrocarbon, oxides of nitrogen and smoke emission is observed with KSPO—diesel blend. In addition, energy and exergy values of KSPO‐diesel with different blends at different loads are evaluated. Fuel exergy rate of the blended fuel is higher than pure diesel fuel where as exergetic efficiency of the blended fuel found is lower than pure diesel fuel. Moreover, the exergetic efficiency is increased with increasing engine load.

Energy recovery from wastewater: Heat over organics

In dealing with wastewater, chemical energy has traditionally been perceived as the only source of recoverable energy in moving towards the carbon-neutral operation of wastewater treatment plants. Based on an estimation of practically recoverable energy embedded in municipal wastewater, however, the potential for thermal energy (90% recovery from wastewater) is much higher than for chemical energy (COD, 10% recovery). The carrier of chemical energy (COD) has a high exergy value which should, from a sustainability point of view, be utilized to the greatest extent possible. Rather than being converted into methane (and subsequently into carbon dioxide), carbon (COD) contained in wastewater should be converted into highly valuable organic products. Thermal energy could be utilized for district heating/cooling, agricultural greenhouses, and even for drying dewatered sludge. In this way, thermal energy can indirectly offset the energy demand for wastewater treatment. The limitations in utilizing thermal energy are not generally based on technical difficulties; in fact, they can be mainly attributed to supply distances and governmental policies. It would, therefore, be greatly beneficial if municipal authorities would work together to jointly plan utilization of this thermal energy.

Numerical investigation of thermal performance of geometrically modified spherical ice capsules during the discharging period

Ice thermal energy storage (ITES) is a significant option for shifting cooling load from peak hours to off-peak hours in order to reduce the cooling cost and equipment capacity. Encapsulated ITES system is one of the most preferred types of ITES systems, because it is easier to apply and has lower initial cost than other types of ITES systems. Capsule geometries have great impact on the thermal performance of the encapsulated ITES system. Spherical capsules are widely used in the application because they provide better thermal performance due to the ratio of its volume to its surface area. Also, modified capsule geometries are used for increasing the thermal performance of the ITES system. This paper focuses on a numerical study in order to determine the effect of the geometrically modified spherical capsule on the thermal performance during the discharging period. Seven geometrically modified spherical capsules were investigated and compared with the ordinary spherical capsule. The FLUENT 17.1 code was used for numerical analyses. At the end of the study, it was found that geometrically modified capsules provided higher thermal performance than an ordinary spherical capsule in the equal capsule volume. Capsule D provided the longest discharging period of 2118 seconds, when VHTF, in = 0.001 m/s and THTF,in = 275.5 K. The lowest discharging time of 464 seconds was obtained with Capsule A, when VHTF, in = 0.01 m/s and THTF, in = 283 K. Among the studied modified capsules, Capsule F performed the worst thermal performance. Energy efficiency values were high, and they did not give comparable difference between the capsule models and working conditions. While all exergy values were 98.50% and higher, exergy efficiency values changed between 85.12% and 51.91%. Exergetically, Capsule D provided the best thermal performance during the discharging period.

Influence of absorber plate shape factor and mass flow rate on the performance of the PVT system

In this paper, a realistic mathematical model is presented to study the performance of photovoltaic thermal system (PVT). The model considers the effect of control parameters like shape factor (Z) and mass flow rate (m) simultaneously to optimize the efficiency of PVT system. Simulation process based on iterative method is applied to different types of absorber plate shapes namely v-groove and curved shape grooves. To the best of our knowledge curved groove absorber plates has not been considered in the past. Photovoltaic and outlet temperature, electrical and thermal energy and exergy efficiencies, pressure drop are evaluated as a function of mass flow rate using Nusselt and Reynolds number for different Z values. The results indicate fall in temperature both for PV and outlet temperature and rise in energy and exergy values and pressure drop with mass flow rate. It is predicted that efficiency of PVT system can be improved when the value of Z lies in the range (1.3≤Z<2) which corresponds to curve shape grooves in absorber plate. Further it is found that curved shaped grooves in the absorber plate can be a good substitute to V-grooves for low and high values of m.

Thermo-ecological analysis of industrial kilns

In this study, thermo-ecological analysis has been applied by using ecologic objective function "ECO" and ecological coefficient of performance "ECOP" to the kilns used in the firing process of the ceramic plant. Five different environmental (dead state) temperatures (between 10 °C and 30 °C) are taken into account. The irreversibility, which are the most important criteria affecting ecological performance, occurs during the heat transfer in the burners and cooling in the kiln. The irreversibility and product exergy values are compared under different environmental temperatures. The ECO and ECOP values are inversely proportional to the environment temperatures. The maximum ECO and ECOP values are determined as −2387.156 kW and 0.051, respectively, while their corresponding minimum values are −2577.394 kW and 0.026, respectively. The results obtained can be a guide for the thermo-ecological design of industrial kilns. The losses of the kiln are high. It is necessary to reduce the losses to increase the performance and ecologic indicator results. The kilns are not environmentally benign at higher ambient temperatures. The optimum working condition of the kiln can be considered as 10 °C. Better insulations are necessary for the side, bottom and top surfaces of the kilns to reduce the losses. In this regard, the waste heat recovery for the gases can be taken into account for better efficiency and environmental assessment.

Thermodynamic and economic analyses of a hybrid waste-driven CHP–ORC plant with exhaust heat recovery

A smart hybrid power plant comprising a waste-fired CHP (combined heat and power) plant accompanied by a small-scale organic Rankine cycle was recently designed and analyzed thermodynamically. The objective of this hybridization is to maximize the share of electricity production of waste-CHP plants rather than a higher heat production rate in a cost-effective manner. In this work, utilization of the exergy of the hot flue gas of the waste-fired CHP unit in order to increase the potential of the organic Rankine cycle for maximizing the net power output of the hybrid cycle is proposed and techno-economically analyzed. In addition, the effect of using alternative environmentally-friendly organic working fluids on the performance of the system was investigated. The results of the study show that by the flue gas potential utilization of the same CHP unit, the size of the organic Rankine cycle may increase significantly, leading to a larger power output of the plant. As such, the net exergy and energy efficiency values of the combined plant in various operational conditions are improved compared to its primary configuration by, respectively, about 10% and 20%, when both of the main CHP cycle and the organic Rankine cycle are working at nominal load. In addition, this exergy utilization is beneficial economically as well, decreasing the payback period of the parallelization project by about 10% (from 7.4 years to 6.7 years). The alternative organic working fluid does not make a significant change in the technical and economic performance indices of the system.

On the quantification of non-equilibrium exergy for thermodynamic systems evolving according to Cattaneo’s equation

This paper is a follow-up of previous work aimed at the identification and quantification of the exergy of macroscopic non-equilibrium systems. Assuming that both energy and exergy are a priori concepts, it is possible to show that a system in an initial non-equilibrium state relaxes to equilibrium releasing (or absorbing) an additional amount of exergy, called non-equilibrium exergy, which is fundamentally different from Gibbs’ Available Energy and depends on both the initial state and the imposed boundary conditions. The existence of such a quantity implies that all iso-energetic non-equilibrium states can be ranked in terms of their non-equilibrium exergy content, any point of the Gibbs plane corresponding therefore to a possible initial distribution, each one with its own exergy-decay history. The non-equilibrium exergy is always larger than its equilibrium counterpart and constitutes the “real” total exergy content of the system, i.e., the real maximum work extractable (or absorbable) from the system. The application of the method to heat conduction problems led to the calculation of a “relaxation curve”, i.e., to the determination of the time-history of the relaxation towards equilibrium that takes place in finite rather than infinite time interval. In our previous works, use was made of the Fourier heat diffusion equation. In this study, the Cattaneo heat transfer equation is used instead, in an attempt to extend the validation range of the procedure. Cattaneo introduced in 1948 a second time derivative term that renders the diffusion equation hyperbolic and avoids an infinite speed of propagation. A finite propagation velocity of thermal disturbances affects the value of the non-equilibrium exergy: this paper presents the new results and offers a discussion of the implications.

A Holistic Method of Assessing Efficiency and Sustainability in Agricultural Production Systems

Until now, no single universally adaptable method exits for complete assessment of efficiency and sustainability of agricultural production systems. Existing methods are limited for analyzing agricultural systems. This paper presents the Emergy-Data Envelopment Analysis method; which we built from aggregating Emergy Analysis (EMA) and Data Envelopment Analysis (DEA) into a framework, to provide improved accounting of resource and energy use efficiency including absolute and relative sustainability of agricultural production systems. The method of assessment is as follows. An emergy diagram of the production system is drawn to visually represent the system. Inputs and outputs of the system are estimated on an annual base in their standard physical units of measurement. The available energy content (exergy) of input and output resources are calculated respectively using appropriate methods of calculating exergy for each given input and output. This is done assuming the concept of energy memory. Using Microsoft excel, the emergy of the input and output resources are calculated as the mathematical product of resource exergy and unit emergy value (UEV). The refined procedure of emergy calculation by Brown and Ulgiati (2016) is applied, and it leads to the retainment of selected inputs and outputs of various resource types. The emergies of the selected resource inputs and outputs from comparative peer systems of production (decision making units - DMUs) are concatenated into a table (.csv format), and imported into a model of DEA. The optimization function in DEA applies Pareto efficiency to estimate the relative technical efficiency (rTE) scores among peer units. The score value is a proxy indicator for relative sustainability. The calculated UEV of a product equates to eco-efficiency, and it is applied to evaluate the resource and energy use efficiency. Selected emergy-based indicators of proven reliability are applied for the evaluation of absolute sustainability. The composition of the evaluation outcomes provides improved accounting information that contributes to completeness of assessed efficiency and sustainability of agricultural systems as a whole.