Heat Transfer Temperature Difference Research Articles

Thermodynamic analysis and optimization of hydrogen liquefaction system with binary refrigerant precooling cycle

A hydrogen liquefaction process is proposed with the liquid natural gas utilization, binary refrigerant precooling and helium cryogenic cycles combined, and a general model is built for analyzing the variation of hot and cold composite curves and heat transfer temperature difference (HTTD) along with refrigerant parameters. The relationship between temperature and enthalpy of the precooling cycle and the variation of HTTD are deduced. Based on this, the composite curves and HTTD curves are constructed, and the influence of refrigerant on the HTTD and the refrigerant outlet temperature is analyzed. The optimization procedure of refrigerant is proposed based on the temperature-enthalpy relationship and HTTD considering the temperature glide. For the proposed hydrogen liquefaction system, the optimal binary refrigerant includes 60.21 % nitrogen and 39.79 % propane (mass fraction), and its mass flow rate and inlet temperature are 23,821.96 kg/h and -199.72 °C, respectively. The corresponding specific energy consumption (SEC) of the hydrogen liquefaction system is 4.44 kWh/kgLH2, reduced by 10.30 %, and the coefficient of performance (COP) and exergy efficiency are 27.10 % and 28.26 %, increased by 11.34 % and 17.80 %, respectively.

Thermo-economic optimization on a combined heat and power system with supercritical Rankine cycle for power-to-heat batteries

The global energy structure is transforming to low-carbon, and it is urgent to construct a sustainable energy system mainly based on renewables. The power-to-heat batteries (P2HBs) show great potential for large-scale energy storage by converting low-cost renewable power to heat. This paper aims to study the thermodynamic and economic advantages of the P2HB integrated with a supercritical steam Rankine cycle (RC) to achieve combined heat and power (CHP) generation. Firstly, a system model of P2HB-CHP consuming grid valley power is developed. The system includes three sub-systems: P2HB, steam generator, and CHP. Thermodynamic and economic analysis models are developed, and the average exergy efficiency (ηav) and net present value (NPV) are formulated as performance evaluation targets, respectively. The genetic algorithm is used to perform multi-parameter optimization of the system. The thermodynamic optimization results show that the maximum ηav of supercritical P2HB-CHP is 0.47 %, 1.16 %, and 1.44 % higher than that of subcritical P2HB-CHP when the high working temperature of the molten salt reaches 505 °C, 570 °C, and 640 °C, respectively. The largest proportion of anergy is generated by electric heaters, over 72 %. The next largest proportion is heat exchangers, which is related to the heat transfer temperature differences. The results of the economic analysis show that the maximum NPV of supercritical P2HB-CHP is lower by 158 M$, lower by 74 M$, and higher by 55 M$ than that of subcritical P2HB-CHP when the high working temperature of the molten salt is reached 505 °C, 570 °C, and 640 °C, respectively. The high efficiency of supercritical RC reduces the costs of electric heaters and molten salts, but sets high demands on the heat exchangers. Although high-temperature molten salt results in high energy efficiency, the increased cost of molten salt reduces the profitability of the system.

Performance evaluation and optimization of compact tube-fin latent heat storage system in phase change nanoemulsion discharge mode

The low thermal conductivity of phase change materials (PCMs) and the reduced heat transfer temperature difference along a tube both limit the thermal performance of latent heat thermal energy storage (LHTES). Herein, a compact tube-fin LHTES system based on phase change nanoemulsions was developed and the heat transfer process of nanoemulsion and PCM was numerically investigated. The effects of the heat transfer structure of the heat exchanger and the thermophysical parameters of the heat transfer fluid (HTF) on the cold energy discharge performance of the system were quantified. The optimized model reduced the discharge time by 24.4 % in nanoemulsion mode relative to water. Heat transfer improvement on the PCM side could be achieved by decreasing the fin spacing and tube spacing and by increasing the fin thickness. Such improvement reinforced the heat transfer enhancement of the nanoemulsion. The heat transfer mechanism was explained by the temperature distributions of the HTF and PCM along the tube. The phase-change thermostatic properties of the nanoemulsion and PCM contributed to the formation of dual-phase-change coupled heat transfer (i.e., the heat transfer process when the fluid inside the tube and the PCM filled outside the tube undergo a simultaneous phase change) within the LHTES, increasing the heat transfer temperature difference and the magnitude of the driving force. Increasing the phase change temperature difference accelerated the onset of dual-phase-change heat transfer, while increasing the PCM content prolonged the process. Briefly, this study provided operational and design assistance for LHTES systems in nanoemulsion mode with the intention to accelerate heat transfer rates.

Numerical study of heat transfer characteristics of intermittent flow cold storage surface heat exchanger

The intermittent flow cold storage surface heat exchanger is a key component of the new pulse tube expansion cryogenic refrigerator, which is responsible for the periodic heat transfer of cold and hot helium, and its heat exchange efficiency directly affects the thermodynamic efficiency of the whole machine. In this study, a three-dimensional model of the heat exchanger unit is established, and numerical simulation is employed to investigate its heat exchange characteristics. The analysis focuses on understanding the internal temperature distribution patterns within the heat exchanger and explores the influence of wall materials on its heat transfer characteristics. Results show that the existence of the temperature lag loop minimizes the effective heat transfer temperature difference, consequently decreasing the heat exchanger’s efficiency. Moreover, the choice of wall material significantly affects the performance of the heat exchanger, with optimal thermal conductivity and volumetric specific heat enhancing its efficiency. This research provides valuable insights for future design and improvement of similar heat exchangers.

Efficient and economic water and heat recovery from flue gas by novel hydrophilic polymeric membrane condenser

The membrane technology for water and heat recovery from flue gas possesses the advantages of a simple structure and high water quality. In this study, we propose a novel hydrophilic polymeric membrane condenser (HPMC) to efficiently recover water and heat from flue gas. Compared to current hydrophilic ceramic membrane condenser (HCMC), HPMC offers the benefits of cost-effectiveness and high packing density. An experimental investigation is conducted to explore the fluid flow characteristics as well as the water and heat recovery performance of HPMC. The maximum recovered water flux reaches 6.7 kg/(m2·h), while the maximum recovered heat flux amounts to 18.6 MJ/(m2·h). Enhancing gas/water flow rates or increasing heat transfer temperature difference can significantly improve both recovered water and heat fluxes. Notably, it is found that thermal resistance primarily stems from the polymeric membrane, emphasizing the importance of enhancing the membrane's thermal conductivity to improve HPMC performance. The overall heat transfer coefficient can be enhanced by increasing the gas/water flow rate, while the influence of gas/water temperature on the overall heat transfer coefficient is relatively insignificant. Furthermore, by fitting experimental data, a correlation formula for friction factor is obtained, which greatly enhances accuracy in pressure drop calculations under practical operating conditions. Based on the technical and economic analysis, the payback period for HPMC is merely 0.3 years, significantly shorter than that for HCMC, thereby indicating a substantial potential for commercial application of HPMC. This study demonstrates that the HPMC is an excellent candidate for recovering water and heat from flue gas, and the fundamental data provides valuable foundational insights for future enhancement of HPMC.

Experimental research and energy effectiveness analysis on chip-level two-stage loop thermosyphon system for data centre free cooling

The development of 5G technology has put forward new requirements for computing the abilities of chips, and chip power has also significantly increased. Consequently, the heat load of the rack will increase rapidly in the future. Traditional computer room air conditioning (CRAC) systems cannot satisfy the rack’s high heat flux dissipation requirements, and new cooling forms such as chip-level cooling should be adopted. In this study, a two-stage chip-level cooling system, which is pumpless and waterless, offers flexible and detachable installation based on practical requirements, was proposed. The cooling system removes heat from the chips to the outdoors via two thermosiphon loops, where the heat is first transferred to cold plates tightly attached to the chip surfaces, then transferred through heat exchangers attached to the rack side, and finally dissipated outdoors through air cooling. In this study, a two-stage chip-cooling system was constructed and tested in an enthalpy-difference laboratory. The effects of the liquid filling ratio on the thermal resistance, total temperature difference, and fluid flow pattern under different heat loads were investigated. Second, a heat transfer model for analysing thermal resistance networks was constructed, and the proportions of different types of thermal resistance were determined. Third, an energy-saving analysis of the system is established. The experimental results showed that at single chip heat load 200 W and total heat load 2 kW, the heat transfer temperature difference between chips and outdoors is less than 20 °C at extremely high energy efficiency (cooling load factor reaches 0.05 at outdoor temperature 40 °C), which makes it feasible for free cooling throughout the year in most Chinese areas. The annual PUE in Beijing using the proposed system is 1.15, which indicates a 30 % reduction of the total energy consumption of data centres.

The influence of operation parameters on concentration ratio of multi-effect evaporation system with mechanical vapor compression

MVC (mechanical vapor compression) evaporation technology has become a hot research topic due to low energy consumption and high efficiency. Based on conservations of energy and mass, the mathematical model of a multi-effect evaporation system with mechanical vapor compression (MEE-MVC) is established to analyze the effects of key operating parameters. The relationship between concentration ratio (CR) and specific power consumption (SPC) is revealed. Results indicate that more evaporator effects can promote the CR when the total heat transfer temperature difference keeps constant. It can be found that when the total heat transfer temperature difference is greater than approximately 10°C, the CR of different systems are almost fixed between 1.2 and 2.5, but the SPC can reach more than 15kWh/t. CR gradually increased as the temperature of last-effect evaporator secondary vapor increased, and the increase is about 0.3. In particular, by changing the total heat transfer temperature difference or the temperature of secondary vapor of the last effect to increase the CR, the SPC can be reduced and better energy-saving effects be obtained. The change of the CR with the final secondary vapor temperature is the combined effect of boiling point elevation (BPE) and latent heat of the secondary vapor.

Heat transfer performance study of a separated pulsating heat pipe

In order to study the heat transfer performance of the pulsating heat pipe (PHP) under the separation arrangement of evaporating and condensing ends, this paper designs a separated PHP for experimental investigation, and describes its heat transfer capability in terms of the wall temperature oscillation performance, the heat transfer temperature difference and the heat transfer thermal resistance. Under different heating powers, the effects of different placement inclinations and their structures on the heat transfer performance of the in-line and bent separated PHP are analyzed. The study shows that in the low heat transfer power scenario, the performance of the in-line type separated PHP is more excellent, and with the increase of the placement of the inclination of the heat transfer situation is further optimized, 90 ° placement of the inclination of the optimal performance of the heat transfer; bent type separated PHP condensing end of a certain level of inclination is conducive to low-power startup and operation, the condensing section of the 15 ° horizontal angle of the optimal performance; and in the high heat transfer power, the two performances are similar, but the arrangement of flexible bent type separated PHP is more suitable for the changing heat transfer scenarios.

EXPERIMENTAL INVESTIGATION ON THE APPLICATION POTENTIAL OF FINLESS HEAT EXCHANGER WITH MINI-DIAMETER TUBES UTILIZED AS AIR HEATER OR AIR COOLER

Increasing the ratio of the internal and external surface areas of heat exchangers is ordinarily considered to be an effective way of improving performance. In this paper, a novel finless heat exchanger with mini-diameter tubes used as air heater or air cooler is proposed. In order to fully understand the performance of this novel type of heat exchanger, a test bench was established. The heating and cooling performances were tested according to relevant standard specifications. Furthermore, the heat exchanger was compared with seven conventional heat exchangers. This novel heat exchanger has excellent surface heat transfer temperature difference uniformity. Relative to the seven traditional heat exchangers examined, this novel design demonstrated remarkable heat transfer enhancements, registering gains of at least 173% as an air heater and a staggering 277% as an air cooler. However, it also exhibited elevated waterside flow resistances. Critically, conventional empirical heat transfer equations proved suboptimal for this system, necessitating modifications that yielded new coefficients: C = 0.0839 and n = 0.992.

Experimental and numerical investigation on the cold harvest of composite phase change materials for building energy conservation

This paper investigates the cold energy storage of a horizontal shell-tube latent heat thermal energy storage (LHTES) unit for the cold harvest during night time. An experimental apparatus containing a horizontal circular tube with circumferential heating/cooling was designed and developed. Paraffin based phase change material (PCM) with a melting temperature of 27 °C was adopted as the cold harvest media. To improve the heat transfer rate, multi-walled carbon nanotubes (MWCNTs) were mixed with the paraffin to form a composite PCM with high thermal conductivity. A corresponding model of the composite PCM was developed and verified against the experimental data. Numerical simulations were performed for different boundary temperatures and concentrations of MWCNTs. The results show that when the heat transfer temperature difference is 20 °C, 0.05 wt% nanoparticles increase the melting rate of PCMs. When the heat transfer temperature difference was 40 °C, 0.10 wt% nanoparticles significantly affect the PCM melting rate. For low or high temperature (heat transfer temperature difference of 10 °C and 80 °C), the addition of nanoparticles is not conducive to improving the melting rate.

Numerical investigations of a latent thermal energy storage for data center cooling

The thermal performance of a 115 L latent heat storage prototype for cooling data centers was investigated. Experimentally, the heat transfer power and heat absorbed by the heat exchanger during the charging and discharging processes were measured at two flow rates (5 and 10 L/min). Numerically, two phase-change models were developed using the enthalpy and effective heat capacity methods, respectively. The results showed that the enthalpy method provides an overall better prediction of the absorbed heat, whereas the other method only agrees well with the measured results during the melting process. Thus, it is suggested that further modification of the effective heat capacity with temperature improves the agreement between the results. For a volume flow rate of 5 L/min, the average heat transfer power predicted by the enthalpy model was 2290 W during the melting process and > 920 W during the solidification process due to the smaller temperature difference for heat transfer caused by supercooling. The prototype achieved the highest average heat exchange capacity rate when melted to a 50% of its total capacity. This study provides a baseline for predicting and improving the thermal performance of latent heat storage.

A integrated mechanical vapor compression enrichment system of radioactive wastewater: Experimental study, model optimization and performance prediction

Evaporation technology has unique advantages in the enrichment of radioactive ions, which can deal with the high concentration of radioactive wastewater. A integrated mechanical vapor compression (MVC) enrichment system with high efficiency filter was proposed and studied experimentally for radioactive wastewater, whose decontamination factor was 37107.1 for Co2+, 2741.3 for Sr2+, and 52545.5 for Cs+, which saved energy by 76.7–84.3% and operation cost by 72.0–81.0% when compared to the conventional single effect (SE) evaporation system. Exergy destruction and efficiency of the single screw compressor were 7.26 kW and 34.0%, respectively, which should be prioritized for improvement. Mathematical models based on both the heat transfer coefficient (HTC) and coefficient of performance (COP) were established and optimized experimentally, the ideal running parameters were 90–110 kPa for evaporating pressure, 8.5–11.5 °C for heat transfer temperature difference, 1.50–1.60 for compression ratio and 2.0–4.0 kPa for filtration pressure difference, respectively. It will supply the theoretical and data basis for development and design of MVC enrichment system of radioactive wastewater.

Finite time thermodynamic optimization for performance of absorption energy storage systems

Absorption energy storage (AES) has attracted worldwide attention due to the high energy storage density and environmental friendliness. To optimize the performance of the AES system, a finite time thermodynamic (FTT) model considering some influencing factors such as time, heat transfer area, heat transfer temperature difference, internal friction and dissipation has been developed in this paper. A new concept of ratio of charging and discharging time is proposed. The general relation of the energy storage efficiency, energy storage rate and energy release rate are induced based on FTT analysis. The distribution of the total thermal conductivity was optimized under the condition of a certain total thermal conductivity and the optimized maximum cooldown release rate has been increased by 14%. The optimal operating conditions of the AES system are obtained. Furthermore, the influences of the internal irreversibility, ratio of charging and discharging time and heat source temperatures on the performance of the AES system are analyzed. The research results can provide theoretical basis and guidance for the AES system design and optimization.

Origin and Evolution of Cracks in the Glaze Surface of a Ceramic during the Cooling Process.

Because of the significant difference between the thermal expansion coefficients of ceramic blank and glaze, the glaze typically undergoes more pronounced shrinkage than the blank during ceramic cooling, which results in high stress concentrations and cracking. In this study, the mechanical mechanism of glaze cracking is studied, based on the statistical strength theory, damage mechanics, and continuum mechanics. Furthermore, the influence of the glaze layer thickness, heat transfer coefficient, expansion coefficient, and temperature difference on the creation and propagation of inner microcracks is systematically investigated, and the final discrete fracture network of ceramics is discussed at the specific crack saturation state. The results show that (1) a higher heat transfer coefficient will lead to a more uniform distribution of the surface temperature and a faster cooling process of the ceramics, reducing the number of microcracks when the ambient temperature is reached; (2) the thinner glaze layer is less prone to cracking when its thickness is smaller than that of the blank. However, when the thickness of the glaze layer is similar to that of the blank, the increased thickness of the glaze layer will increase the number of cracks on its surface; and (3) when the expansion coefficient of the glaze layer is smaller than that of the blank, cracks will not occur inside the glaze layer. However, as the coefficient of the thermal expansion of the glaze layer continuously rises, the number of cracks on its surface will first increase and then decrease.

Building Energy Saving for Indoor Cooling and Heating: Mechanism and Comparison on Temperature Difference

Reducing the heat transfer temperature difference via reasonable indoor temperature determination and air conditioning system design is a confirmed building energy-saving approach for space cooling and heating. However, the energy-saving mechanism cannot be explained scientifically and comprehensively while maintaining the cognitive level of the heat transfer law. In this paper, based on the same climatic conditions and decreasing range of indoor and outdoor temperature difference, the yearly and monthly absolute energy-saving amount (ESA) and relative energy-saving ratio (ESR) are investigated and compared for cooling and heating, respectively, to reveal the energy-saving mechanism for cooling and heating from the microscopic perspective. Two new concepts, including ESA by temperature difference and behavioral ESA by measure itself, are defined. The yearly ESA for cooling or heating caused by the decreasing of temperature difference is composed of those two factors. For cooling, the contribution rate of the behavioral ESA at those moments within the decreasing range of the temperature difference can be up to 78%, while for heating is only 7%. This work can provide theoretical support for building energy system design optimization and method reference for energy-saving analysis of building air conditioning systems with temperature difference considerations for cooling and heating, respectively.

Superstructure design and optimization on closed Brayton cycle system of fluoride-salt-cooled high-temperature advanced reactor

To exploit the advantages of Fluoride-Salt-cooled high-Temperature Advanced Reactors (FuSTAR) such as high temperature, inherent safety, compact structure, and modularization, an energy conversion system based on a closed Brayton cycle was adopted, and the superstructure design was optimized to attain the best parameters and configuration. To enhance the convergence rate of a single computation, the simultaneous equation method was employed, while the particle swarm method was utilized to prevent local optimality. Irreversible analysis and sensitivity analysis were performed to evaluate the system's performance. The findings demonstrate that thermal efficiency can be significantly enhanced by incorporating reheating into the system. Furthermore, for air and Ar, the recompression intercooling configuration proved effective in reducing the heat transfer temperature difference and enhancing thermal efficiency. For CO2 and Xe, the incorporation of reheating, recompression, and intercooling significantly improved thermal efficiencies beyond 53%, indicating their immense potential for further development. Introducing reheating into the Xe cycle led to a substantial increase in both thermal efficiency and the area of the temperature-entropy graph. The irreversible analysis revealed that for CO2 and SF6, the predominant loss occurred in the cooler and recuperator. In contrast, for the Xe cycle, all kinds of irreversible losses were evenly distributed across each device. Sensitivity analysis indicated that the thermal efficiency of near-critical fluids was more sensitive to the lowest pressure than that of far-critical fluids. Both the near-critical split ratio and the far-critical minimum pressure had a significant impact on the mass flow rate. The design results of this method can guide the selection of the optimal power cycle system configuration for FuSTAR.

Uncertainty quantification by probabilistic analysis of circular fins

Abstract The temperature distribution and thermal Stresses induced by a temperature difference for steady state heat transfer in silicon carbide (SiC) ceramic tube heat exchanger with circular fins was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for the hoop stresses due to the structural and thermodynamic random variables. These results are used to identify the most critical design variables in order to optimize the design and make it cost effective. The probabilistic analysis leads to the selection of the appropriate measurements to be used in structural and heat transfer analysis and to the identification of both the most critical measurements and parameters.

Exergy Analysis of a Shell and Tube Energy Storage Unit with Different Inclination Angles

To optimize the utilization of solar energy in the latent heat thermal energy storage (LHTES) system, this study conducts exergy analysis on a paraffin-solar water shell and tube unit established in the literature to evaluate the effects of different inclination angles, inlet temperatures, original temperatures, and fluid flow rates on the exergy and exergy efficiency. Firstly, the thermodynamic characteristics of the water and the natural convection effects of the paraffin change with different inclination angles. When the inclination angle of the heat storage tank is less than 30°, the maximum exergy inlet rate rises from 0 to 144.6 W in a very short time, but it decreases to 65.7 W for an inclination angle of 60°. When the inclination angle is increased from 0° to 30°, the exergy efficiency rises from 86% to 89.7%, but it decreases from 94% to 89.9% with the inclination angle from 60° to 90°. Secondly, under the condition that the inclination angle of the energy storage unit is 60°, although increasing the inlet temperature of the solar water enhances the exergy inlet and storage and reduces the charging time, it increases the heat transfer temperature difference and the irreversible loss of the system, thus reducing the exergy efficiency. As the inlet water temperature is increased from 83 to 98 °C, the exergy efficiency decreases from 94.7% to 93.6%. Moreover, increasing the original temperature of the LHTES unit not only reduces the exergy inlet and storage rates but also decreases the available work capacity and exergy efficiency. Finally, increasing the inlet water flow rate increases the exergy inlet and storage rates slightly. The exergy efficiency decreases from 95.6% to 93.3% as the unit original temperature is increased from 15 to 30 °C, and it is enhanced from 94% to 94.6% as the inlet flow rate is increased from 0.085 to 0.34 kg/s with the unit inclination angle of 60°. It is found that arranging the shell and tube unit at an inclination angle is useful for improving the LHTES system’s thermal performance, and the exergy analysis conducted aims to reduce available energy dissipation and exergy loss in the thermal storage system. This study provides instructions for solar energy utilization and energy storage.

Numerical investigation of bed-to-tube heat transfer in a shallow fluidized bed containing mixed-size particles

Mixed-size particles with low processing cost have great potential to act as the absorbing media in the next-generation concentrated solar power plants. However, the research on the heat transfer from the particles to heated surfaces in gas–solid fluidized beds is limited. In this paper, the bed-to-tube heat transfer coefficient (HTC) in a shallow fluidized bed with immersed tubes is determined numerically. The Eulerian–Eulerian approach that incorporated the kinetic theory of granular flow has been implemented in a two-dimensional model. The distribution of the local HTC around the tube is investigated for various particle systems. The results show that the HTC reaches a maximum at the upper right (45°) and upper left (135°) of the tube, respectively, indicating a strong relation between the local HTC and solid volume fraction (SVF). The average HTC increases as the mean particle size gets smaller. For monosized particles, the HTC increases from 925 W/(m2·K) to 3033 W/(m2·K) as the particle size decreases from 300 to 100 µm. For binary particles, the growth in the HTC is nonlinear, with an increase in growth rate being observed as the small-size component becomes dominant. For mixed-size particles with the same mean size, a higher HTC can be achieved by enlarging the size difference between the components. A modified correlation for predicting the bed-to-tube HTC is established. Besides, the impacts of gas velocity and temperature, and heat radiation on the bed-to-tube HTC are discussed. It is found that an optimal gas velocity exists to maximize the average HTC and SVF simultaneously, while the gas temperature has a minor contribution. Due to the small heat transfer temperature difference, the effect of thermal radiation on the HTC can be neglected even though the bed temperature reaches 800 °C.

Multi-objective optimization of recompression S-CO2 cycle for gas turbine waste heat recovery

Recompression supercritical carbon dioxide Brayton cycle (RCSCBC) has important application prospects in the fields of gas turbine waste heat recovery. A RCSCBC model considering finite temperature difference heat transfer between heat reservoir and working fluid, irreversible compression, irreversible expansion and other irreversibility losses is established. Then the mass flow rate of the working fluid, cycle pressure ratio and the heat conductance distribution ratios of four heat exchangers are taken as optimization variables, the multi-objective coordinated optimization with net power output, exergy efficiency, thermal efficiency and ecological function as the goals is carried out, and an artificial neural network model is constructed to solve the problem of long optimization time. The results show that the decision-making result by Shannon Entropy method for the four-objective optimization has the lowest deviation index, and is the optimal. Compared with the initial design point, the thermal efficiency of the cycle for the optimization results by the Shannon Entropy method can reach 40.69%, which is increased by 29.8%. The net power output can reach 10.972 MW, which is increased by 9.5%. The ecological function can reach 7.265 MW, which is increased by 114.75%. The exergy efficiency can reach 74.72%, which is increased by 24.22%.