Exergy Recovery Research Articles

Optimization of thermoelectric generator power density for cryogen cold exergy recovery

The article presents the optimization of the power density of a thermoelectric generator (TEG) operating in cryogenic temperature conditions. Optimization of TEG power density was performed as a function of TEG leg length and its effect on TEG performance. The figure of merit (ZT) of the TEG was experimentally verified for the temperature range of a cold sink from 160 to 250 K, which corresponds to the temperature of the wall subjected to the boiling film of LNG. The numerical model proposed in the article was verified by comparison with experimental data, and then used to simulate the operation of the TEG at a cold sink temperature of 80 K corresponding to the wall temperature in the process of LH2 regasification. The obtained results showed that the optimal length of TEG legs is less than 10 mm and depends on the boiling and heat transfer regime. The results of the presented research can be used to improve the effectivity of cold exergy recovery from cryogenic systems.

Optimization of Exergy Efficiency in a Walking Beam Reheating Furnace Based on Numerical Simulation and Entropy Generation Analysis

An analysis of entropy generation and exergy efficiency can effectively explore the energy-saving potential of reheating furnaces. This paper simulated the combustion, flow, and heat transfer in a walking beam reheating furnace by establishing a half-furnace model. The entropy generation rate distribution of different thermal processes was numerically calculated. The effect of slab residence time and fuel distribution in the furnace was studied to optimize exergy efficiency. The results indicated that combustion and radiative heat transfer are the primary sources of entropy generation. Irreversible losses accounted for 26.39% of the total input exergy, in which the combustion process accounted for 16.43%, and radiative heat transfer accounted for 8.47%. Reducing the residence time by 60 min decreased irreversible exergy loss by about 2.5% but increased heat dissipation and exhaust exergy loss by 5.8%. Energy saving can only be achieved when the heat exchanger’s exergy recovery efficiency exceeds 36% under different fuel supplies. Keeping the total fuel supply unchanged, increasing the fuel mass flow rate in heating-I zone while decreasing it in heating-II zone resulted in a 1.5% decrease in exergy efficiency. This study provides new insights into the energy-saving potential of reheating furnaces.

Optimization and exergy analysis of a cascade organic Rankine cycle integrated with liquefied natural gas regasification process

One of the most efficient methods of exergy recovery during the regasification process is integrating the LNG stream with an Organic Rankine Cycle (ORC) to generate electricity. This study employs a cascade structure of ORC consisting of two double-stage condensations operating at 6 bar regasification pressure. To obtain an optimal ORC system integrated with an LNG, three optimization levels for a specific heat source are addressed, including process variables, working fluids, and structure. Ten process variables and two working fluid variables for the top and bottom cycle among 13 candidates of refrigerants were optimized to provide the maximum power output. The results determined that refrigerants of R41 and R1150 have the best performance in the optimized process conditions for the top and bottom cycles, respectively. For the regasification of 36 tonnes per hour of an LNG stream, the produced net power and the exergy efficiency are achieved by 2116.76 kW and 0.29, respectively. The exergy analysis revealed that employing the double-stage condenser ORC is not a good choice. Accordingly, a cascade-parallel structure is proposed for further studies.

Extensive Analysis of a Reinvigorated Solar Water Heating System Using Low-Density Polyethylene Glazing

Solar energy is one of the most promising forms of alternative energy because it has no adverse effects on the environment and is entirely free. Converting solar energy into thermal energy is the most common and straightforward method; the efficiency of solar thermal conversion is approximately 70 percent. The intermittent nature of solar energy availability affects the performance of solar water heaters (SWH), which lowers the usefulness of solar energy in residential and commercial settings, particularly for water heating. Even at low temperatures, the performance of a collector can be improved by using low-density polyethylene (LDPE) glazing instead of traditional glass because it is less expensive and lighter than glass. Using a comprehensive experimental-simulative study, the Glass Solar water heater (glass SWH) and the low-density polyethylene solar water heater (LDPE SWH) are analyzed, examined, and compared in this work. These solar water heaters have galvanized iron (GI) as their absorber material. The SWHs were operated in a closed loop at a constant mass flow rate of 0.013 kg/s, and a 4E analysis (which stands for energy, exergy, economics, and efficiency recovery ratio) was carried out. This analysis included a look at the dynamic time, uncertainty, weight reduction, carbon footprint, and series connection. An LDPE SWH has an energy efficiency that is 5.57% and an exergy efficiency that is 3.2% higher than a glass SWH. The weight of the LDPE SWH is 32.56% lower than that of the glass SWH. Compared to the price of a conventional geyser, installing our SWH results in a cost savings of 40.9%, and monthly energy costs are reduced by an average of 25.5%. Compared to October, September has the quickest dynamic time to reach the desired temperature, while October has the most significant dynamic time. The efficiency recovery ratio (ERR) of a glass SWH is 0.0239% lower than that of an LDPE SWH. LDPE SWHs had a carbon credit worth INR 294.44 more than glass SWHs. The findings of these tests demonstrate that the LDPE SWH is a practical replacement for traditional means of heating water, such as SWHs and geysers.

Energy-Based Aerodynamic Loss and Recovery Characteristics of Adiabatic and Heated Fuselages

An energy-based aerodynamic analysis of the mechanical loss generation and potential energy/exergy recovery mechanisms is carried out for adiabatic and heated 2D axisymmetric flows over fuselage-shaped axisymmetric bodies. A generality of these mechanisms is obtained from dimensional analysis by appropriately scaling the freestream Reynolds and Mach numbers, while varying a reference fuselage’s fineness ratio. Thermo-aerodynamic implications and synergies of boundary-layer heating on the loss distribution, energy, and heat exergy recovery potentials are further considered for varying wall temperature ratios. The result is a clear identification of partial dynamic similarity and heat transfer effects on flow mechanisms such as shear layers, separation bubbles, and shockwaves of axisymmetric flows, and subsequent implications on loss distribution and energy recovery characteristics relating to boundary-layer ingestion. The analysis indicates that dissipating heat from aircraft surfaces aids, circumstantially, to drag reduction of unpowered fuselage bodies and increases, relative to the adiabatic, the recoverable energy fraction available for the boundary-layer ingestion propulsor, by strategically manipulating the loss distribution, while removing excess heat from the aircraft’s subsystem (batteries, fuel cells). Finally, an approach to assess the feasibility of exergetic heat recuperation as a possible means of useful work extraction and improved aerodynamic performance is explicitly introduced and discussed in the paper.

Environmental sustainability and exergy return on investment of selected solar dryer designs based on standard and extended exergy approaches

ABSTRACT Different solar dryer designs are available in the literature. However, it is essential to understand how the performance of the dryer designs contributes to environmental sustainability by reducing waste in the exergy-loop and mitigate CO2 emission into the atmosphere. The exergy-based sustainability indices include waste exergy ratio, lack of productivity (LOP), sustainability index, environmental destruction coefficient and exergy recovery ratio. The paper also introduces exergy return on investment (ExRoI) by applying an extended exergy accounting approach with the inclusion of exergy influx of material resources, capital and labor in the exegetic computations of the sustainability index. Four solar dryers consisting of an indirect solar-cabinet dryer, mix-mode solar dryer, hybrid solar dryer and a double-partitioned single-pass-collector solar dryer with a wind generator were used as a case study. Comparatively, the ExRoI is lower than the standard exergy-efficiency for the four dryers by 6.87 to 91.61%. In contrast, the standard exergy-based sustainability index was higher by 5.4 to 61.2%. Total invested exergy ranged from 0.04TJ to 0.081TJ. The values of waste exergy ratio, LOP, ERR, EDC, and carbon credit ranged from 0.47 to 0.79, 0.566 to 16.45, 5.44 × 10−4 to 1.37 × 10−1, 1.57 to 17.45 and 231.45 to $2908, respectively.

Application of dividing wall column in azeotropic distillation with intermediate boiling-point heteroazeotrope: Simulation and optimization

Dividing wall column (DWC), as a proven process intensification technology, has been used widely in separation of ideal multi-components, and some azeotrope systems. For heterogeneous azeotrope with the potential possibility of crossing distillation boundary by liquid-liquid splitting, it is advantageous to integrate liquid-liquid decanter with distillation column, especially with DWC to further simplify flowsheets and reduce energy consumption. In this work, existing heterogeneous azeotrope separation processes are described, and an innovative DWC-based process (MHADWC) is proposed for intermediate boiling-point heteroazeotropic systems. Then an industrial case of MIPK system, is used to evaluate mentioned configurations by rigorous simulation and optimization. These configurations are compared and analyzed in detail on energy consumption, exergy analysis and equipment invest. The results show that, from the perspective of process energy consumption, MHADWC process has the most advantages, because it saves 37% of energy consumption; if both equipment costs and exergy recovery are taken into account, HADWC2 has a higher thermodynamic efficiency (43.5%) at its TAC and can be used as a preferred target. And in this work, purification of an intermediate boiling-point heteroazeotrope is the main difference of these processes compared with the well-known heterogeneous azeotropic distillation process where the top vapor product is the lowest boiling point of the ternary system.

Assessment of eco‐thermal sustainability potential of a cluster of low‐cost solar dryer designs based on exergetic sustainability indicators and earned carbon credit

This research aims to establish the interconnectivity between solar dryer designs and the exegetic-sustainability performance of solar dryers. This is to assist energy policymakers and fabricators to establish design standards and make the right choice for waste exergy management strategy for environmental sustainability. Therefore, in this study, the exergy-based sustainability indicators and earned carbon credit were used to assess and compare the performance of four different designs of solar dryers of equal collector capacity under the same external environmental conditions in the same town. In terms of better sustainability indicators that include high exergy efficiency, lower waste exergy emission, higher sustainability index and lower lack of productivity, solar dryer designs with single-pass triple air movement direction with inlet air powered by wind generator had the best indices for environmental sustainability. In contrast, the natural convection mix-mode solar dryer design had the lowest environmental effect factor and destruction coefficient while the indirect natural convection solar dryer had the highest energy recovery ratio based on exergy output from water evaporation. However, the mix-mode solar dryer powered by the wind generator earned the highest carbon credit. The exergy efficiency ranged from 19.09 to 52 % for the four cases, whereas the waste exergy ratio ranged from 0.52 to 0.81. The LOP value ranged from 2.95 to 19.96. Similarly, the sustainability index ranged from 1.28 to 2.5, the average environmental destruction coefficient varied from 3.96 to 20.96, the exergy recovery ratio for the four dryers varied from 0.001825 to 0.12405, and the earned carbon credit ranged from $442. 3 to $2630.5.

Hydrogen and ammonia production from low-grade agricultural waste adopting chemical looping process

Chemical looping hydrogen production (CLH2) is a new technology used to produce hydrogen (H2) from fuels while separating CO2 simultaneously. This research aims to build an integrated conversion system of rice husks, a high energy potential biomass, to H2 with high energy efficiency. The developed system mainly consists of superheated steam drying, steam gasification, chemical looping, and Haber-Bosch processes. Three different systems are developed and compared. The first and second systems employ direct chemical looping (DCL) using H2O and CO2 as gas enhancers for the reducer, respectively, while the third system adopts syngas chemical looping (SCL). Exergy recovery and process integration technologies are adopted to enhance energy and exergy efficiencies. A mixture of Fe2O3 and Al2O3 is used as oxygen and heat carriers in the CLH2 module. Process modeling, optimization, and evaluation of both energy and exergy efficiencies are conducted using Aspen Plus. Some crucial operating parameters, including reactor temperature, pressure, the oxygen carrier flow rate, and gas enhancer flow rate, are selected to evaluate the performance of the system, especially in terms of efficiency. The highest achievable H2, NH3, and net power efficiencies are 51.8%, 38.09%, 0.65%, respectively, when DCL is adopted with CO2 as a gas enhancer during the reduction.

Novel industrial gas filling station with an internal cooling system dedicated for speeding up cylinder charging process - Energy and exergy analysis

In the paper, a novel patented system which meets the demand to shorten gas cylinder charging times is described and investigated. It has been analytically proven that the charging time of a 50-L gas cylinder can be reduced to 15 min (twice as fast as in conventional systems) and keep its temperature within safe limits when the cylinders are cooled. The second advantage of the introduced novel system is the cold exergy recovery from the evaporation process of the liquefied gas. The recycled cold fully covers the demand for cooling power, making the system self-sufficient. A very useful and common method to evaluate the thermal performance of any recovery system is energy and exergy analyzes, which are also applied to the presented system. The paper provides numerical simulations based on linear thermodynamic analysis, supported by CFD simulations. To optimize the cold exergy recovery and cylinder cooling process, three different cooling intensities are compared: ΔT = 10, 20, 30 K. These are defined by the assumed growth of the gas temperature during the filling process. A smaller temperature increase means a higher cooling airflow rate, which results in a more intense cooling process. Analyses were carried out for three selected gases: argon, nitrogen, and oxygen, all compressed to the same final pressure of 30 MPa. In total, it gives nine different cases, which are analyzed and compared. Analysis brings a deeper insight into the system and provides indications for designing a real installation.

Hydrogen Production from Low-Grade Agricultural Waste: Integrated Drying, Gasification, and Chemical Looping

Chemical looping hydrogen production (CLH2) is a new technology used to produce H2 from fuel while separating CO2 simultaneously. Rice husk is considered as a promising energy source in the future because of its high energy potential and carbon neutral characteristics, although currently it is not being used effectively. This research aims to build an integrated conversion system of rice husks to H2 with high energy efficiency. The developed system mainly consists of superheated steam drying, steam gasification, syngas chemical looping, and Haber-Bosch process. To enhance the efficiency, exergy recovery and process integration technologies are adopted. Fe2O3 and Al2O3 are used as oxygen carrier and heat carrier for CLH2. The energy efficiency is evaluated using Aspen Plus. The effect of chemical looping temperature, and the effect of recycle to feed stream ratio for NH3 synthesis were selected for the parameters and evaluated. The highest NH3 efficiency achieved through the simulation was 5.77 % and the power efficiency was 1.96 %.

Research on the effectiveness of the key components in the HAT cycle

Humid Air Turbine (HAT) cycle is considered to be one of the most advanced gas turbine cycles due to its high efficiency, flexible operation, low NOX emissions, and low investment cost. The heat recovery determines the temperature field distribution of the humidification process, which is critical to the performance of the HAT cycle. However, so far, the effect of heat recovery of heat exchangers on cycle performance is still a research gap. Filling up the research gap is of great significance to the full utilization of the thermodynamic potential of the HAT cycle. This paper built a humid air turbine cycle with additional heat exchangers (aftercooler, regenerator, economizer) based on a humid air turbine test rig. A comprehensive thermodynamic analysis of the effectiveness of the heat exchanger components had been carried out. To conclude, the water–air ratio, aftercooler effectiveness and regenerator effectiveness can effectively affect the humidification performance and efficiency. The above analysis provided a theoretical reference for the actual transformation and performance enhancement of the test rig. In addition, research on the influence of the water–air ratio on the HAT cycle at different power outputs showed that the optimal water–air ratio gradually decreases with the increase of power output. The effect of the pressure ratio on the HAT cycle was clarified by comparison with a simple regenerative cycle. Finally, exergy analysis of the HAT cycle was carried out based on different optimization strategies. For the humid air turbine of 4 MW-class, increasing recuperator effectiveness is one of the effective techniques to enhance exergy recovery as well as efficiency, and improving the proportion of exergy utilized for water evaporation can augment specific work output. The maximum efficiency of 48.5% was obtained where its corresponding exergy efficiency reaches 44.4%. The maximum specific work output of 560.6 kJ/kg was achieved with an exergy efficiency of 38.0%.

Energy and exergy and economic (3E) analysis of a two-stage organic Rankine cycle for single flash geothermal power plant exhaust exergy recovery

A two-stage ORC (Organic Rankine Cycle) is being proposed for the recovery and utilization of low-grade heat from single flash geothermal power plant exhaust flue fluids. The working fluids for two-stage the recovery system are R227ea and R116. The impact of essential design parameters such as inlet temperature of the cycle, ambient temperature, geothermal turbine inlet pressure, geothermal condensation temperature on system performance are investigated using thermodynamic mathematical models regarding energy and exergy efficiencies as the objective function. The addition of the recovery section to the base cycle improves the thermal efficiency from 0.2023 to 0.2178, a 7.66% improvement in this critical metric. Furthermore, the exergy efficiency rises from 0.55044 to 0.5803, representing a 15.04% boost in exergy efficiency. Furthermore, the system's overall output rises from 7690 kW to 9898 kW, representing a substantial gain of 28.71%. The suggested recovery system's cycle has a lower LEC than a single flash geothermal cycle from an economic standpoint. LEC Reduced from $ 0.125 per kilowatt to $ 0.108 per kw, a cost savings. As a result, including a recovery section in the basic single flash geothermal cycle will significantly improve system performance.

Numerical investigation of the air-particles heat transfer characteristics of moving bed - effect of particle size distribution

Particle vertical moving beds (PVMB) are widely used in industry, usually accompanied by gas-solid heat exchange or chemical reaction. It is worth noting that the actual industrial particles usually have a wide particle size distribution (PSD), which is an important property that can influence the hydrodynamics and heat conversion in moving bed system. Therefore, understanding the multiphase flow and thermal behavior of PVMB with multi-size particles is essential for process designing and optimizing. Based on the CFD-DEM coupling method, a mathematical model of gas-solid heat transfer for PVMB with different PSDs is established- all with the same mean particle diameter. Furthermore, the effects of 3 influential factors on the exergy transfer in a small PVMB were analyzed. Results show that an increased PSD range leads to an increased specific surface area, but this does not imply a favorable heat transfer between air and particles in PVMB, which is contrary to the findings related to the fixed bed. Increasing particle mass flow rate or particle inlet temperature will cause the cooling air and particle outlet temperature to increase approximately linearly. More interestingly, as inlet air mass flux increases, exergy recovery efficiency decreases, however with the further increase of inlet air mass flux, exergy recovery efficiency reaches a minimum and then gradually increases. Exergy recovery efficiency decreases and tends to be flat with increasing particle mass flow rate. This method is an essential procedure for modeling the heat transfer of discrete particles in industrial-scale equipment.

Multi-criterion comparison of compression and absorption heat pumps for ultra-low grade waste heat recovery

Heat pump is effective to recover ultra-low grade waste heat, and includes compression and absorption heat pumps. However, the driving source of these heat pumps are different. This makes the efficiency comparison unfair, and multi-criterion comparison is necessary. In this paper, the compression and absorption heat pumps are compared under the same condition, where 30 °C waste heat is recovered to provide 60 °C domestic heating supply. Analyses with coefficient of performance (COP), second law efficiency, exergy efficiency and exergy rate are carried out. Exergy-to-energy ratio of driving source, instead of temperature, is used to unify the evaluation of different driving sources. Results show that compression heat pump has higher COP but lower exergy efficiency, indicating more irreversible loss. This is followed by double effect, single effect and double lift absorption heat pumps. The high COP lead to effective recovery of exergy from waste heat, with higher exergy rate. However, the strong sensitivity of COP versus temperature lift in compression heat pump makes it more effective under small temperature lift, while absorption heat pumps are more effective under higher temperature lift. The multi-criterion comparisons provide both deeper understanding about heat pumps and useful framework for waste heat recovery analysis.

Synergies between aliphatic bio-alcohols and thermo-chemical waste heat recovery for reduced CO2 emissions in vehicles

The impact of aliphatic (C1–C5) bio-alcohols for on-board thermo-chemical exhaust waste heat recovery, H2 production and hence fuel savings for a gasoline direct injection (GDI) engine has been investigated with iso-octane as reference. Gibbs free energy analysis was conducted to establish which reaction pathways for fuel reforming were dominant and how these reactions are influencing H2 and CO yield. To obtain engine exhaust temperature and mass flow maps for several steady-state engine operation conditions, an engine model was created in AVL CRUISE M and validated with real GDI engine data. A methodology was developed to couple the thermodynamic reactor results and engine model results to compute waste exhaust heat recovery by accounting limited available exergy in exhaust and optimising reforming reactor’s operational parameters to maximise exergy recovery and reforming efficiency in the reformer. Under steady state engine operation, iso-pentanol was more effective overall due to its high hydrogen content by weight (8.3% and 4.3% higher than methanol and ethanol respectively), high energy density of 34.6 MJ/kg (42.2%, 22.3% 13.2% and 4.3% higher than C1-C4 alcohols respectively), high reforming endothermicity and the versatility for heat recovery under all engine operation conditions with heat recovery of at-least 2% of engine power even under low-load conditions.Subsequently, the engine model was evolved into a full AVL CRUISE M vehicle model and was studied over a duty-cycle to evaluate the fuels further. Iso-pentanol and iso-propanol were most effective concerning average heat recovery over the duty cycle. For the high-speed regions of the cycle, up-to 9% of waste heat recovery is observed for C4 and C5 bio-alcohols. In terms of vehicle’s carbon emissions, iso-pentanol, n-butanol, and ethanol exhibited maximum CO2 reduction of 8.4%, 7.7% and 7.1% respectively. The results presented herein indicates versatility of bio-alcohols for cleaner and more efficient powertrains.

Thermal-chemical conversion of sewage sludge based on waste heat cascade recovery of copper slag: Mass and energy analysis

Thermo-chemical conversion method can transform sewage sludge (abbreviated as SS) to bio-char with hydrogen-rich gas and has good prospects for development. In this research, copper slag was used as heat carrier and provide energy for conversion process of SS. A method of carbonization-activation waste heat cascade recovery technology system was designed. In this technology process, multi-stage endothermic chemical reactions absorb sensible heat from hot copper slag particles. Syngas, activated carbon (abbreviated as AC) and char are produced from SS. Mass and energy balance of this system were evaluated. The results showed that waste heat recovery efficiency and byproducts' additional value were improved by this method comparing with traditional water quenched method. Increasing heat quantity of carbonization process can improve system's energy recovery ratio. In theory, under the optimal condition (T2 = 700 °C, T3 = 200 °C), waste heat recovery ratio and exergy recovery ratio reach 90.8% and 94.9%, respectively.

Performance analysis of solar driven combined recompression main compressor intercooling supercritical CO2 cycle and organic Rankine cycle using low GWP fluids

Current study deals with performance evaluation of the solar power tower driven recompression with main compressor intercooling (RMCIC) supercritical CO2 cycle incorporating the parallel double evaporator organic Rankine cycle (PDORC) as bottoming cycle using low global warming potential fluids to reduce the global warming and ozone depletion. Using the PDORC instead of the basic organic Rankine cycle, waste heat from the intercooler and cycle exhaust were recovered simultaneously to enhance performance of the standalone RMCIC cycle. Exergy, thermal efficiency, efficiency improvement and waste recovery ratio were considered as performance parameters. A computer program was made in engineering equation solver to simulate the model. It was concluded that by the incorporation of the PDORC thermal efficiency was improved by 7–8% at reference conditions. Maximum combined cycle's thermal and exergy efficiency were found 54.42% and 80.39% respectively of 0.95 kW/m2 of solar irradiation based on R1243zf working fluid. Among the results it was also found that maximum waste heat was recovered by the R1243zf about 54.22 % at 0.95 effectiveness of low temperature recuperator.

Thermodynamics and Parametric Study of the Grate ClinkerCooler Using the Process Model

In cement industries, grate coolers are commonly used for heat recovery from hot clinker discharged from the rotary kiln. The study focuses on improving a grate cooling system’s energy, exergy, and recovery efficiencies by optimizing its operating parameters such as cooling air and clinker mass flow rate. Aspen plus V10 process simulator was used to explore the impact of clinker mass, and ambient cooling airflow rate on the thermodynamics efficiencies of a cooling system for grate cooler. The energy and exergy efficiency of the grate clinker cooler gives estimates of 85.9% and 56.2 % respectively. Whereas the energy and exergy recovery of the grate clinker cooler was estimated as 75.9 % and 45.4 % respectively. It was found that a cooling system’s energy and exergy efficiencies can be improved by 2.1 % and 2.2 %, respectively, for each 5 % rise in cooling air mass. Considering the utilization of the heat recovery efficiencies of the exhaust air cooling system, energy and exergy recovery have been found to increase by 8.5 % and 9.2 % respectively. It was discovered that significant emission reductions of 0.23 % can be achieved by raising both secondary air and tertiary temperature via optimization of the grate cooler parameter, resulting in a reduction of fuel for kiln operations. Nevertheless, these units provide opportunities in great potential for energy savings, therefore the method used can also aid informed decision-making to enhance process performance.

The Possible Coupling of LNG Regasification Process with the TSA Method of Oxygen Separation from Atmospheric Air.

Liquefied Natural Gas (LNG) must be vaporized before it is used in the combustion process. In most regasification terminals, energy that was previously expended to liquefy natural gas is dissipated in the environment. The paper proposes the use of the thermal effect of LNG regasification for the atmospheric air separation as a possible solution to the LNG exergy recovery problem. The presented idea is based on the coupling of the LNG regasification unit with an oxygen generator based on the Temperature Swing Adsorption (TSA) process. Theoretical analysis has revealed that it is thermodynamically justified to use the LNG enthalpy of vaporization for cooling of the TSA adsorption bed for increasing its adsorptive capacity. It has been shown that 1 kg of LNG carries enough exergy for separating up to approximately 100 g of oxygen using the TSA method. Although the paper suggests using the enthalpy of LNG vaporization for atmospheric air separation, similar processes for other gas mixture separations using the TSA method can be applied.