Fluid Side Research Articles

Improving a shell-tube latent heat thermal energy storage unit for building hot water demand using metal foam inserts at a constant pumping power

The phase transition heat transfer during the melting and solidification processes of phase change materials (PCMs) was modeled in a shell-tube thermal energy storage unit. For the first time, special attention was dedicated to the heat transfer enhancement on the heat transfer fluid (HTF) side by placing metal foam (MF) inserts in the HTF tube. The MF inserts on the HTF side were placed next to the fin bases to produce the maximum heat transfer enhancement. A two-temperature local thermal non-equilibrium model was applied to accurately model the transient heat transfer in the MF domains. To perform a fair heat transfer analysis and consider the hydrodynamic aspects of heat transfer, the pumping power for driving the HTF fluid was kept fixed. The finite element method with automatic time-step control was used to integrate the model equations. Results show that the insertion of the MF in the HTF tube enhances conduction heat transfer but reduces flow for a constant pump power. Using a small amount of MF provides a good flow rate and a convective heat transfer while using a large amount of MF provides good conduction heat transfer but a poor flow rate and convection. A moderate amount of MF inserts results in poor conduction and a poor flow rate, notably increasing the phase transition time. A 5 % MF insert could provide about a 13 % shorter solidification time compared to a 25 % MF insert. Thus, a well-designed and engineered MF insert configuration on the HTF side can reduce the phase transition time and improve the energy storage power.

A shell-tube latent heat thermal energy storage: Influence of metal foam inserts in both shell and tube sides

Enhancing heat transfer in latent heat thermal energy storage systems is of utmost importance to facilitate the efficient absorption and release of thermal energy. The primary objective of the current study is to investigate the influence of a metal foam layer on heat transfer enhancement in both the heat transfer fluid side and the shell side. The research explores the incorporation of a fixed 30 % foam layer, which can either extend along the tube wall or penetrate deeper into the shell, moving away from the heat transfer fluid tube. A local thermal non-equilibrium two-temperature heat equation model is utilized to mathematically model the interactions within the metal foam embedded in the heat transfer fluid tube and the phase change material domain. The governing equations are solved using the finite element method. The results indicate that adjustments to the inlet pressure and the metal foam shape parameter (FL) can significantly reduce the melting time, with a variation of approximately 40 %. Specifically, at a constant inlet pressure of 750 Pa, the energy storage power at a 90 % charging increases from 32.2 W (FL = 0.75) to 48.7 W (FL = 1.37). A modification of FL shape parameter increased the power output by 34 %.

Dynamic wetting of a CO2-H2O-montmorillonite system using molecular dynamics

Injecting carbon dioxide into shale reservoirs achieves geological carbon sequestration (GCS), effectively reducing atmospheric carbon dioxide levels. Rock wetting characterizes the strength of the interaction between fluids and rocks, thereby determining fluid distribution, which is crucial for GCS trapping efficiency. In this study, the dynamic wetting of H2O-montmorillonite and CO2-H2O-montmorillonite systems was studied using molecular dynamics (MD) simulations. Montmorillonites with different lattice substitution arrangements based on pyrophyllite are strongly water-wet, and a precursor film forms at the leading edge of the bulk water. Na+ controls precursor film formation, which is rapidly spreading forward at a constant speed along the lattice substitution site lines based on Na+ distribution. The lower the proportion of Al3+/Si4+ lattice substitution in the Si-O tetrahedral layer on the fluid side, the higher the degree of water-wetness. The competitive adsorption of carbon dioxide and water molecules reduces the degree of spreading, resulting in a decrease in the degree of water-wetness. However, compared to the H2O-montmorillonite system, the spreading behavior remained unchanged. High carbon dioxide pressure caused the wetting to change from strongly water-wet to weakly water-wet, however no wetting reversal was exhibited. The wetting changes were particularly prominent near the supercritical carbon dioxide pressure, with a limit of 18 MPa. For the first time, this study distinguished the dynamic behaviors of bulk water and precursor films, revealed the formation mechanism of precursor films, and revealed the control mechanism of carbon dioxide pressure on dynamic wetting from a molecular perspective. The quantitative relationship between the contact angle and flow velocity at different carbon dioxide pressures presented in this study could effectively guide the establishment of a fluid force equation for infiltrating flow, providing theoretical support for GCS numerical simulation research.

Effect of steam flow parameters on the partial load behaviour of a PCM storage

To estimate the achievable thermal power in passive latent heat thermal energy storage (LH-TES) systems and the corresponding charging/discharging times for customised storage design and operation, relevant influencing parameters and their impact must be sufficiently known and understood. These parameters include not only the well-researched parameters on the phase change material (PCM) side, but also the parameters on the heat transfer fluid (HTF) side, such as the inlet temperature, the mass flow rate and the resulting heat transfer coefficient (HTC) between the HTF flow and the tube wall. For heat exchangers, these influences have been studied well, however for highly transient LH-TES studies are scarce. This article presents the influence of relevant parameters focusing on the ones related to the HTF side, using analytical and numerical parameter studies in Matlab®. The effect of different HTCs for varying flow conditions of the HTF in different zones of the tube is utilised to introduce the dominant heat transfer surface between the storage and the HTF (DHTS) as an indirect operating parameter. It corresponds to the area where the HTF phase change occurs and where most of the total energy is transferred. The numerical study indicates that the size of the dominant heat transfer area and thus the DHTS can be adapted by the HTF mass flow rate and the temperature difference between the HTF inlet temperature and the PCM phase change temperature. Based on this knowledge, new conjugate design and operating strategies for a test rig with a nominal thermal power of 1 kW using the commercial PCM PLUSICE A133 as storage material are proposed. They lead to a peak shaving behaviour of the storage with defined charging and discharging times.

Fluid/p-form duality

In this study, we demonstrate that an inviscid fluid in a near-equilibrium state, when viewed in the Lagrangian picture in d+1 spacetime dimensions, can be reformulated as a (d−1)-form gauge theory. We construct a fluid/p-form dictionary and show that volume-preserving diffeomorphisms on the fluid side manifest as a U(1) gauge symmetry on the (p+1)-form gauge theory side. Intriguingly, Kelvin's circulation theorem and the mass continuity equation respectively appear as the Gauss law and the Bianchi identity on the gauge theory side. Furthermore, we show that at the level of the sources, the vortices in the fluid side correspond to the p-branes in the gauge theory side. We also consider fluid mechanics in the presence of boundaries and examine the boundary symmetries and corresponding charges from both the fluid and gauge theory perspectives.

Performance evaluation of a moonbase energy system using in-situ resources to enhance working time

The solar energy resources of the Moon are far more prosperous than those of the Earth. Therefore, energy systems driven by solar energy are more suitable for application on the Moon. Ensuring the safe operation of the energy system under solar energy (or other variable-temperature heat sources) has become a focal point issue that constrains the construction of the moonbase. In this paper, based on the closed Brayton cycle-organic Rankine cycle (CBC-ORC) system and considering the dryness of the outlet of the evaporator of ORC, a scheme is proposed to raise the temperature of the heat source by using a heat storage heat exchanger (HSHEX). Thus increase the dryness of the organic working fluid side of the evaporator. With the introduction of HSHEX, ORC can work for up to 13.3 days at a mass flow rate of 0.6 kg/s, nearly one time more than the case without HSHEX. The maximum total system thermal efficiency can reach 28.74 %. By stopping the CBC and adjusting the ORC mass flow rate, the average power generation gets 5.69 kW, doubling the working time during the lunar nighttime. This paper aims to solve the problem of improving the working time of the moonbase energy system and provide theoretical guidance for constructing the future lunar base energy system.

Numerical analysis and optimization of the heat transfer enhancement from the heat transfer fluid side in a shell-and-tube latent heat thermal energy storage unit: Application to buildings thermal comfort improvement

This study investigates the impact of enhancing the convective heat transfer on the Heat Transfer Fluid (HTF) side by passive flow manipulation on the melting and solidifying kinetics of a Phase Change Material (PCM) in a shell-and-tube Latent Heat Thermal Energy Storage (LHTES) unit. The PCM used is PureTemp 23 (PT23), a commercial bio-sourced product. The targeted application is the development of a LHTES unit for improving the thermal comfort in buildings through a combined heating and cooling approach. The study is carried out using the commercial code STARCCM+ and the enthalpy-porosity method, with appropriate implementation of the buoyancy source term. The numerical approach used for phase change modeling has been validated by comparisons with reference data from the open literature. Delta Wing pairs (DWg) and Delta Winglet pairs (DWt) vortex generators (VGs), were first inserted into the tube in which the HTF flows. Parametric analysis on the aspect ratio, position, and VGs number were performed, and optimization was done on the attack and rolling angles. The Performance Evaluation Criteria (PEC) index, which takes into account the heat transfer enhancement achieved and the related pressure losses, was used as an assessment criterion to evaluate the heat transfer augmentation of the studied enhanced tube with VGs. The results show that maxima can be reached for the different parametric studies carried out. While PEC increases with the attack angle until a maximum beyond which it decreases, it decreases consistently with the rolling angle. Once the enhanced optimal tube equipped with a shell containing the PCM, the results of the detailed study made on the kinetics for charging and discharging period of the enhanced LHTES unit reveal important gain for the storage unit. The heat transfer enhancement achieved result into more than 110 % increase in the PCM's melting/solidifying kinetics in the shell, thanks to an increase in the heat duty exchanged between the HTF and the PCM, leading to a considerable reduction of complete melting/solidification time. It was observed that the enhanced and optimized LHTES unit developed in the present study has a huge potential for improving buildings seasonal thermal comfort.

Numerical investigation of heat transfer and pressure drop characteristics on the hot fluid side of the plate-fin precooler under negative pressure conditions

Plate-fin heat exchangers are widely employed in aerospace and many other fields due to the advantage of high efficiency and low resistance. However, they usually operate at atmospheric or high-pressure conditions. In this study, The commercial CFD solver Fluent 16.0 was used to evaluate the overall performance of the plate-fin precooler whose hot fluid is nitrogen under negative pressure and high temperature conditions. The characteristics of the hot fluid flow field inside the precooler with and without fins were investigated. The effect of fin number on the heat transfer and pressure drop characteristics of the hot fluid side was analyzed. Furthermore, the comprehensive performance of the precooler under different pressure conditions was compared quantitatively. The results showed that under negative pressure conditions, the hot fluid flow field features inside the precooler without fins was regular, while that of the precooler with fins took on a “<” shaped flow features, indicating the evolving of thermal boundary layer. It was also found that the comprehensive performance of the precooler did not increase with an increase in the number of fins when the hot fluid was in a low-density and high-speed flow state. Moreover, pressure conditions did not affect the heat transfer performance of the precooler but had a significant impact on the pressure drop performance.

Information theory-based dynamic feature capture and global multi-objective optimization approach for organic Rankine cycle (ORC) considering road environment

Efficient capture and global optimization of organic Rankine cycle (ORC) operating features in road environment is the key to obtain actual waste heat recovery potential. The complexity of time-varying characteristics intensifies the nonlinear coupling relationship between ORC performance and parameters. This paper first designs and builds an ORC experimental system for recovering waste heat from internal combustion engine (ICE). The experimental system includes ICE and its measurement subsystem, ORC subsystem, expander lubrication subsystem, cooling subsystem, and ORC measurement subsystem. R245fa is used as working fluid; The expander adopts a specially designed single screw expander. The performance of ORC waste heat recovery is tested by adjusting the operating conditions of the ICE, expander, pump, and valve opening. The temperature range of waste heat is 627–686 K. Subsequently, a dynamic feature capture and global multi-objective optimization approach for ORC is proposed. The results show that the precision of dynamic feature capture can be improved at least 41.78% with the introduction of information theory in complex environment. Frequent fluctuation of vehicle speed is not conducive to the improvement of evaporator inlet temperature at working fluid side. As the speed of the vehicle is greatly reduced, the evaporator inlet temperature drops sharply. The frequent fluctuation of speed will intensify the nonlinear correlation between operating parameters and system performance and make the system performance more dependent on the coupling correlation between operating parameters. The approach proposed in this paper can provide a new idea for efficient capture of dynamic characteristics and global multi-objective optimization of ORC in road environment.

Three-field partitioned analysis of fluid–structure interaction problems with a consistent interface model

This paper proposes a new Fluid–Structure Interaction computational framework. The coupling between the solid and an incompressible fluid is formulated by means of the method of localized Lagrange multipliers (LLM). Instead of applying a direct coupling between the fluid and the structure, which is the traditional approach, LLM introduces an intermediate surface with its own degrees of freedom that is connected to the fluid and structure sides using independent fields of localized Lagrange multipliers. This approach allows the connection of non-matching meshes with mortar or classical localized methods and provides consistent dynamic equations of motion for the interface that can be integrated in parallel. Interface multipliers are later eliminated and the interface motion is used to update the fluid and structure states. This way, dedicated stand-alone software modules for the fluid and the structure are connected to a third interface system treating their interaction, thus preserving the modularity of the single-discipline software modules. Different numerical examples are solved with the proposed methodology to prove its efficiency and accuracy by running a series of classical dynamic FSI benchmark problems.

Impact of nanoparticle shape on entropy production of nanofluid over permeable MHD stretching sheet at quadratic velocity and viscous dissipation

The goal of this study was to determine the effect that NP shape has on the entropy produced by Al2O3−H2O nanofluid across a permeable MHD stretching sheet under the conditions of quadratic velocity, thermal radiation, and viscous dissipation. H2O is the cold fluid, while Al2O3−H2O nanofluid, which includes five various NP forms (oblate spheroid, platelet, blade, brick, and cylinder), is the hot fluid. Nanofluid containing Al2O3−H2O sees widespread use in industrial production because of its remarkable capacity to boost heat transfer. Via a sequence of similarity transformations, the controlling PDEs are converted into a nonlinear differential system of linked ODEs. An efficient implementation of the Runge-Kutta method for getting numerical solutions may be found in the code, which is written in MATLAB. As the φ grows from 0% to 2% or from 0% to 4%, the wall shear stress rises by roughly 6.3% and 12.6%, respectively, in the area that is behind the stretched sheet. Including the magnetic effect in the boundary layer flow at a rate of around 5%, the rate of convective heat transfer increases by about 16.4%. In comparison to nanofluids containing brick-, blade-, cylinder-, and platelet-shaped NPs, the Os-shaped NP nanofluid experiences a greater increase in thermal entropy on the cold fluid side.

Numerical analysis of vibration response of elastic tube bundle of heat exchanger based on fluid structure coupling analysis

Abstract A tube bundle heat exchanger is a typical heat exchange equipment that exchanges heat between two fluids with different temperatures. Through this equipment, one fluid can be cooled down and another fluid can be heated up to meet their respective needs. The equipment is widely used in chemical, petroleum, pharmaceutical, energy, and other industrial sectors, and is one of the indispensable and important equipments in chemical production. To improve the heat transfer performance and service life of the heat exchanger, a numerical analysis of the vibration response of the elastic tube bundle in the heat exchanger based on fluid–structure coupling analysis is proposed. Using the weak coupling method of fluid–structure coupling, the vibration response of multiple rows of elastic tube bundles induced by shell side fluid in a heat exchanger with different tube row spacing and different tube row numbers is studied numerically, and the effects of shell side fluid and tube side fluid on the vibration response of elastic tube bundles are compared and analyzed. The results show that the maximum relative error of monitoring point amplitude is 43.36% when H = 40 mm and 10.17% when H = 70 mm. For connection IV, the maximum relative error of monitoring point amplitude is 31.71% when H = 40 mm and 24.08% when H = 70 mm. This is because when H is small, the interaction between rows of tube bundles is strong, so the amplitude changes violently with the number of the tube bundle. The step-by-step calculation strategy of rough calculation and actuarial calculation proposed in this article can greatly reduce the calculation time and improve the calculation efficiency.

Various nanoparticle shapes and quadratic velocity impacts on entropy generation and MHD flow over a stretching sheet with joule heating

The purpose of this research was to examine the impact of NP shape on the entropy production of a water-alumina nanofluid over a permeable MHD stretching sheet at quadratic velocities with viscous dissipation and joule heating. The hot fluid is water-alumina nanofluid, which consists of four different NP shapes (brick, platelet, blade, and oblate spheroid), and the cool fluid is water itself. As a result of its exceptional ability to enhance heat transmission, Al2O3-H2O nanofluid is used extensively in industrial production. The governing PDEs are changed into a nonlinear differential system of coupled ODEs by a series of similarity transformations. The code, in MATLAB, is an effective version of the Runge-Kutta technique for obtaining numerical solutions. In the region behind a stretching sheet, the wall shear stress increases by almost 6.3% for increases in the volume fraction of nanoparticles from 0% to 2% and by 12.6% for increases from 0% to 4%. When the magnetic effect accounts for roughly 5 percent of the boundary layer flow, there is an approximately 16.4 percent increase in the rate of convective heat transfer. The frictional force and thermal entropy produced by nanofluids with blade-, brick-, and Os-shaped NPs was lower than that produced by nanofluids with platelet-shaped NPs. On the cold fluid side, the nanofluid with Os-shaped NPs develops thermal entropy at a faster rate than those with brick-, blade-, cylinder-, and platelet-shaped NPs.

Estimation of Ranque-Hilsch vortex tube performance by machine learning techniques

This study planned to model a counter-flow Ranque-Hilsch Vortex Tube (RHVT) using compressed air and oxygen gas by machine learning to separate the thermal temperature. From within machine learning models, Linear Regression (LR), Support Vector Machines (SVM), Gaussian Process Regression (GPR), Regression Trees (RT), and Ensemble of Trees (ET) were preferred. By leaving the outlet control valve on the hot fluid side fully open, data were received for each material and nozzle at RHVT with inlet pressure starting from 150 kPa and up to 700 kPa at 50 kPa intervals. In the counter flow RHVT, the lack in the literature has been tried to be eliminated by modeling the RHVT by finding the difference (ΔT) between the temperature of the cold flow exiting (Tc) and the temperature of the leaving hot flow (Th). When analyzing each of the machine learning models in the study, 80% of all data was used as training data, 20% of all data was used for the test, 70% of all data was used as training data, and 30% of all data was used for the test. As a result of the analysis, when both air and oxygen fluids were used, the GPR method gave the best result with 0.99 among the machine learning models in two different test intervals of 70%–30% and 80%–20%. The success of other machine learning models differed according to the fluid and model used.

Proteomic Differences Between the Ovulatory and Anovulatory Sides of the Mare's Follicular and Oviduct Fluid.

The follicular fluid and oviduct fluid play major roles in oocyte maturation, sperm activation, and fertilization. To better understand the physiological environments for equine oocyte maturation and fertilization, here we conducted the proteome analysis and comparison on follicular fluids and oviduct fluids from the ovulatory side and the anovulatory side. The results showed that there is no significant difference between two side oviduct fluids, but a total of 71 differential abundance proteins (DAPs) were identified between two side follicular fluids, of which 9 are up-regulated and 62 are down-regulated in ovulatory side follicle fluid versus anovulatory side follicle fluid. As we expected, the function classification and enrichment results indicate that up- and down-regulated proteins are largely related to oocyte meiosis, maturation and ovulation. Noticeably, among 9 up-regulated DAPs in ovulatory side follicle fluid, as the DAP with the greatest fold change, PLA2G1B may be a newly discovered component that influences the efficacy of horse IVM/IVF. The current findings add to our knowledge of the in vivo conditions and regulation of equine reproduction, as well as the regulatory mechanism underpinning alternative ovulation.

THERMAL TEMPERATURE ESTIMATION BY MACHINE LEARNING METHODS OF COUNTERFLOW RANQUE-HILSCH VORTEX TUBE USING DIFFERENT FLUIDS

In the counterflow Ranque-Hilsch vortex tube (RHVT), the output control valve on the hot fluid side is left entirely open. The data were obtained using polyamide and brass materials and nozzles at 50 kPa intervals from 150 kPa to 700 kPa inlet pressure. In counterflow RHVT, the difference (&amp;Delta;T) between the temperature of the cold outflow and the temperature of the outgoing hot flow was found, and the RHVT was modeled. The deficiency in the literature was tried to be eliminated. In this study, we planned the modeling of a counterflow RHVT using compressed air, oxygen, and nitrogen gas with machine learning models to predict the thermal temperature. Linear regression (LR), support vector machines (SVM), Gaussian process regression (GPR), regression trees (RT), and ensemble of trees (ET) machine learning methods were preferred in this study. While each of the machine learning methods in the study was analyzed, 75&amp;#37; of all data was used as training data, 25&amp;#37; as a test, 65&amp;#37; as training data, and 35&amp;#37; as testing data. As a result of the analysis, when the temperatures of air, oxygen, and nitrogen gases (&amp;#916;T) were compared, the Gaussian process regression method, which is one of the machine learning models, gave the best result with 0.99 in two different test intervals, 75-25&amp;#37;, and 65-35&amp;#37;. In the &amp;#916;T estimations made in all fluids, much better results were obtained in the machine learning models estimations of nitrogen gas when compared to other gases.

Opportunities for improved space heating energy efficiency from fluid property modifications

Unsteady behaviour of hydronic heating systems causes higher mean room temperatures than are required for comfort. Peak room temperatures depend on interactions between thermostats, heat emitters and the room. The importance of fluid properties on such unsteady heating is often misunderstood meaning potential energy savings are overlooked. This paper demonstrates the influence of fluid modifications and indicates a plausible magnitude of the energy saving opportunity. The results showed that fluid side heat transfer coefficient in isolation had negligible effect. Specific heat capacity of the fluid and flow rates were important, as they altered the amount of embedded energy in the heat emitter when thermostat conditions were met. Reductions in mean heating power for steady demand conditions were between 0 and 7% for plausible changes to fluid properties, depending on heat emitter size, room insulation and external temperature. Reductions in individual cycle energy were between 5 and 25%. When considered in the context of intermittent finite duration heating events, those that contained a small number of thermostat cycles demonstrated energy savings that tended towards the reductions in individual cycle energy. Heating events with larger numbers of cycles showed energy savings tending towards the reduction in mean heating power.

Experimental study on transient frictional features of herringbone-grooved mechanical face seals in start-up and stop stages

Evolutions of frictional features of herringbone-grooved face seals during start-up and stop stages are focused on. Transient frictional torques are measured for outer-diameter-side, middle and inner-diameter-side grooved seals and a smooth-face seal based on a formerly developed dedicated test rig. Development of fluid carrying capacity can be deduced for all four seals according to torque evolutions, and lift-off mechanisms are analyzed. Hydrodynamic effect gets smaller with grooves apart from pressurized fluid side, and thereby hydrostatic effect due to face coning by heat generation dominates the fluid film formation as it is for the smooth-face seal. Thermal characteristic time due to thermal lag effect is smaller than accelerating periods. The squeeze effect indicated by the smaller torque of stop stages is also playing a role in transient operation.

Experimentally validated numerical modeling of heat transfer in crossflow air-to-water fin-and-tube heat exchanger

• Crossflow air-to-water FTHEX has been numerically modeled. • Different tube-side inlet boundary conditions have been analyzed. • Numerical results have been compared with experimental measurements. • Water-side thermal resistance has influence on overall thermal performance of FTHEX. • Fully developed inlet boundary condition shows best agreement with measurements. The aim of this work is to analyze different tube-side inlet boundary conditions in order to properly model heat transfer mechanism in a crossflow air-to-water fin-and-tube heat exchanger (FTHEX). For accurately describing conjugated heat transfer, the entire flow length on both fluid sides should be considered. For problem simplifying, domain that include a segment inside the heat exchanger in the water flow direction, is used. This paper studies the effect of fully conjugated heat transfer, including air-side and water-side thermal resistances. Three different numerical models are analyzed by varying the tube-side inlet boundary conditions. In one of these models the water-side thermal resistance is neglected and other two models consider the water-side thermal resistance, but with different velocity and temperature boundary conditions at the water inlets: uniform and fully developed. To validate the proposed numerical models, measurements have been performed on a crossflow air-to-water plain FTHEX. The results show that the numerical model with the fully developed water inlet boundary condition coincides best with the experimental data. It can be concluded that the water-side thermal resistance cannot be neglected, especially when evaluating the air outlet temperature and the overall heat transfer coefficient of heat exchanger.

Elman and back propagation neural networks based working fluid side energy level analysis of shell-and-tube evaporator in organic Rankine cycle (ORC) system

As the heat exchange component of the organic Rankine cycle (ORC) system, the evaporator directly affects the overall operation performance of the system. In this paper, an analytical method for energy level on the working fluid side of evaporator is proposed based on the energy level and enerty theory. The reliability, validity, and correlation of the proposed analytical method are studied by means of theoretical analysis, experimental evaluation, and Elman neural network (ElmanNN). The bilinear interpolation algorithm is used to analyze the non-linear relationship between the system parameters and the energy level on the working fluid side. In addition, the correlation between the heat exchange efficiency of the evaporator and the operating performance of the system is compared. Based on the back propagation neural network (BPNN), the high energy level area on working fluid side is accurately evaluated and verified, the direction and degree of the non-linear mapping relationship between the working fluid side energy level and the system performance are quantitatively evaluated, and the sensitivity of thermodynamic cycle parameters in the high energy level area on working fluid side is quantitatively evaluated. This study provides a novel approach to evaluate the operation of the evaporator in the ORC system. In addition, this study also provides guidance on how to keep the evaporator operating continuously in the high energy level area throughout the experiment.