Phase Change Heat Exchanger Research Articles

A self-satisfying cooling system based on cold energy storage for the locomotive in a high geothermal tunnel

Effective thermal management of locomotive systems is crucial for ensuring the safe operation of trains through high geothermal tunnels. By taking advantage of the frequent alternation of high-temperature tunnels and cold climate environment, a self-satisfying cooling system based on cold energy storage is proposed, in which a phase change heat exchanger between air and phase change material (succinic acid with 20 wt% expanded graphite) is developed to store cold energy outside tunnels and improve air-cooling efficiency inside tunnels. Numerical models are established to examine the thermal environment in a typical tunnel and the effectiveness of the proposed cooling system. The results indicate that because of the heat exhausted from the train and the thermal dissipation from the surrounding hot rock, the air temperature in the tunnel can rise above 50 °C. The proposed cooling system can release the cold energy from phase change material to keep the air outlet temperature below 40 °C, increasing the energy efficiency and reliability of locomotive operation. By examining the effects of locomotive operating conditions and orthogonal analysis of multi-factors, the heat exchanger structure and other operating conditions are recommended for the self-satisfying cooling system. Finally, the cooling system’s effectiveness is confirmed for the full-line operation of the locomotive along the Ya’an-Nyingchi section of the Sichuan-Tibet Railway in both summer and winter climatic conditions. This study is significant because it provides a novel design scheme for locomotive’s thermal management in high geothermal tunnels and other similar engineering conditions with natural cold sources.

Transient thermal management of laser systems using Plate-Fin phase change heat Exchangers: Experimental and computational study

To mitigate transient thermal shocks in lasers and reduce thermal stresses caused by temperature fluctuations, the use of phase change materials (PCMs) in thermal management systems is a viable solution. This study proposes an innovative two-dimensional transient heat transfer model specifically designed for plate-fin phase change heat exchangers (PFPCHEs). The model meticulously simulates the complex heat transfer phenomena within the heat exchanger, including fluid convection, solid thermal conduction, and the phase change processes of PCM. The convective heat transfer coefficient between fluid and plate is calculated using the Wieting correlation. An advanced pulse-mode experimental test platform was constructed to validate the model, dynamically monitoring and recording outlet temperatures and heat exchange performance for stringent experimental comparison. The research explores the impact of key operating parameters such as initial temperature, flow rate, and inlet temperature of the cooling cycle on the performance of the heat exchanger, providing valuable design and control strategies for transient thermal management of laser systems. The experimental results confirm that the model accurately predicts the dynamic response characteristics and temperature distribution of PFPCHEs under multi-cycle pulse loads, with 96% of the predictions within a 10% error margin. A significant finding is that the initial temperature has negligible influence on the heat transfer characteristics when it is below the solid phase temperature of the PCM. Moreover, by meticulously adjusting the flow rate and inlet temperature of cooling cycle, it is possible to effectively maintain the stability of the outlet temperature throughout the entire pulse cycle. This is crucial for minimizing temperature fluctuations within the thermal management system and extending the service life of electronic components.

The high energy spaceborne all-solid-state lasers based on fluid-loop cooling system

We demonstrate a 532.2 nm high-power all-solid-state pulse laser with a repetition rate of 85 Hz, a single pulse energy of 215.8 mJ. The lasers spot size is (3.8, 3.6) mm, and the divergence angle is (0.57, 0.69) mrad. The stable working state of this laser last for 402 s and the pointing stability of the output beam is better than 50 μrad. A fluid loop system based on phase-change energy-storage heat exchanger is designed in this paper in order to solve several key problems induced by the heat dissipation. The laser is working normally in orbit, and it lays the foundation for the development of spaceborne all solid-state laser with high-energy, high-repetition rate.

Numerical Simulation of Rapid Heat Storage in Plate-Fin Phase Change Heat Exchanger

Rapid phase change heat storage has significant application value in high-power density thermal management systems. This paper presents a comparative numerical simulation study of the rapid heat storage and release dynamics of two types of finned plate heat exchangers with different fin shapes. The study reveals that, under the same fin thickness and volume fraction, the contact surface area of triangular fins is 1.6 times that of rectangular fins, but the heat storage rate of triangular fin heat exchangers is 2 times that of rectangular fin heat exchangers. Due to the small characteristic scale and high material viscosity of the heat exchanger, the natural convection velocity of the liquid phase during the heat storage process is low, and its influence on enhancing the heat storage rate is weak.

Dynamic modelling of supplemental cooling systems with vapor compression refrigeration units in civil aircrafts

Newly developed airliners have adopted supplemental cooling systems (SCS) to provide for non-cabin cooling requirements. In the present study, dynamic component models for compressor and phase change heat exchangers were developed with dynamic decoupling and explicit solution methods, and pressure zone separation and solution methods are developed based to obtain dynamic pressures as key values. A dynamic VCRU subsystem model is established, and the result under single-unit startup condition shows pressure deviations less than 0.16 %, with a simulation time ratio of 5.65 %, exhibiting good overall performance at both precision and speed. A dynamic SCS system model is developed, and the simulation of a 9000 s flight took 1973.3 s to complete. Result in the cruise phase shows the condensation and evaporation temperatures are in the ranges of 28.39–31.33 °C and −17.93 to −10.71 °C, respectively, meeting their respective designed ranges of 30 ± 5 °C and −15 ± 5 °C. These results reflects good consistency of the model with actual system characteristics. Control optimization is conducted based on the developed model to eliminate temperature fluctuation. The optimization reduced the maximum temperature deviation from 0.4004 K to 0.0019 K after system starting process, proving the feasibility of control method optimization based on the developed dynamic simulation model.

The Impact of In-Flight Acceleration Environments on the Performance of a Phase-Change Heat Exchanger Unit with Layered Porous Media

The Phase-Change Heat Exchanger Unit in Layered Porous Media (PCEU-LPM) is obtained through frozen pouring processing, and exhibits characteristics such as high thermal conductivity, high latent heat, and high permeability, making it suitable for dissipating heat in airborne electronic devices. This study numerically investigates the impact of aircraft speed acceleration conditions, which lead to weightlessness or overload, on the performance of the PCHEU-LPM, with a particular focus on the influence of natural convection in the liquid-phase region. Initially, a microscale thermal analysis model is established based on the Navier–Stokes equation scanning electron micrograph to calculate the effective thermal conductivity and permeability of the PCHEU-LPM under different porosities. Subsequently, these parameters are incorporated into a macroscale thermal analysis model based on Darcy’s law, employing an average parameter approach. Using the macroscale thermal analysis model, temperature and velocity fields are computed under various porosities, acceleration magnitudes, and directions. The calculation results indicate that as the acceleration increases from α = 0 to α = 10 g, the interface temperature of the PCHTU-LPM decreases by approximately 5.2 K, and the temperature fluctuation decreases by 2.4 K. If the porosity of the PCHTU-LPM is increased from ε = 70% to ε = 85%, the influence of acceleration change on natural convection will be further amplified, resulting in a decrease in the interface temperature of the PCHTU-LPM by approximately 10.2 K and a decrease in temperature fluctuation by 5.8 K. When the acceleration direction is +z, the interface temperature of the PCHTU-LPM is at its lowest, while it is highest when the acceleration direction is −z, with a maximum difference of 15.4 K between the two. When the acceleration direction is ±x and ±y, the interface temperature lies between the former two cases, with the interface temperature slightly higher for ±y compared to ±x, with a maximum difference of 3.9 K between them.

Thermal performance of phase change material based heat exchanger filled with inorganic salt/expanded graphite

Solid-liquid latent heat storage, featured by the high-density energy storage capacity, is promising in facilitating the high-penetration renewable energy. However, the design of the heat exchanger is challenging due to the conflicting objectives between the heat transfer efficiency and energy storage capacity. To this end, this paper introduces a comprehensive evaluation index, based on which an orthogonal based design optimization method is proposed for heat exchangers filled with inorganic salt/expanded graphite composite phase change material (CPCM). A thermophysical properties based numerical model is built to describe and analyze the solidification and melting of CPCM. The comprehensive evaluation index is utilized to quantify the overall change in heat storage/release performance relative to the mass change of the baseline phase change heat exchanger. The orthogonal experimental method is employed to investigate the impact of various heat exchanger structural factors on the comprehensive performance, followed by optimization design. Simulation results indicated that the longitudinally finned heat exchanger outperforms the other two heat exchangers in terms of the comprehensive evaluation index. Moreover, the inlet fluid temperature exerts a more significant impact on the comprehensive evaluation index compared to the inlet fluid velocity. Additionally, the effects of pipe spacing, fin number, fin height, and tube material on the thermal performance of the longitudinally finned heat exchanger were examined and analyzed. Among these factors, the fin height was identified as the most substantial contribution to the heat transfer performance, while the tube material has a minor effect.

Experimental investigation on the use of PCM heat exchangers in Geo-energy piles and walls

The current paper aims to experimentally investigate the thermal performance of geo-energy piles and walls fabricated with Phase Change heat exchangers. Four prototype concrete geo-energy structures (i.e., piles and walls) were tested using two distinct types of heat exchangers, including standard heat exchangers and PCM heat exchangers. The PCM heat exchangers utilized in the current study were filled up with two different types of Phase Change Materials (PCM) with melting points of 26 °C and 42 °C for geo-energy piles and walls, respectively. The thermal efficiency of the geo-energy piles/walls was experimentally assessed over 100 h of continuous operation under cycles of cooling and heating. The findings illustrated that using PCM heat exchangers led to enhancing the heat transfer efficiency of geo-energy piles by 75 % and 43 % in heating and cooling operations, respectively, compared to those achieved using a standard heat exchanger. Furthermore, the heat transfer performance of geo-energy walls with a PCM heat exchanger was enhanced by 43 % and 32 % in heating and cooling tests, respectively, compared to those achieved using a standard heat exchanger. Moreover, the findings indicated that the inclusion of PCM heat exchangers in geo-energy structures contributed to reducing: the impact on soil temperature and thermal interference radius as well as the potential structural damage due to thermal stress.

Simulation and validation of phase change heat exchangers

Due to the depletion of fossil fuel resources and environmental problems caused by global warming, energy generation has greater potential in future engineering. In designing of thermal or refrigeration system phase change heat exchangers play a vital role. Prior to the application of these realistic models, proper analysis is critical. It will provide accurate findings while also reducing research effort, risk, and expense. Analytically, we investigated condensation and evaporation in a fin-tube heat exchanger using ANSYS FLUENT 2022. The fluid flowing inside the tube is refrigerant R22 and the fin side external fluid is considered as atmospheric air. To understand its physical and mathematical behavior, the CFD findings have been validated with MATLAB Simulink. Variations of heat transfer coefficients and pressure drops of the air-side and refrigerant side with various geometry parameters such as tube diameter, fin spacing, and number of rows have been plotted and observed. Results show that the heat transfer coefficient varies from 77.4 W/m2K to 65.6 W/m2K on the air side while 8787 W/m2K to 6339 W/m2K on the Refrigeration tube side. Additionally, the pressure drop varies from 0.0265 kPa to 0.0353 kPa on the air side while 33.1 kPa to 26.2 kPa on the Refrigeration tube side.

Advanced Phase-Change Intermediate Heat Exchanger Development for Multistage Thermoelectric Heat Pumps

The need to reach a full energy decarbonisation is well known. Heating and cooling consumption is almost half of the global energy end-use. Thus, development of low-carbon and highly efficient power-to-heat technologies must be developed. In this work, the use of thermoelectric technology working as a heat pump is proposed to heat up an airflow of 38 m3/h. Two different prototypes of multistage thermoelectric heat pumps have been developed and compared based on monophasic and phase-change intermediate heat exchangers. The reduced thermal resistance obtained for the novel phase-change heat exchanger increases the heat flux supplied to the airflow and reduces the consumed power of the system, outperforming the operation of the monophasic thermoelectric heat pump between a 30 and a 67 %. The novel multistage phase-change heat pump obtains experimental COP values between 3.25 and 1.26 when the airflow rises its temperature from 3.5 °C to 23.5 °C. Additionally, this experimental study proves a new methodology to calculate the supplied heat flux to the airflow. The validation of this technology proves a discrepancy of ± 9 % when this novel technology is compared to the conventional one based on the airflow temperature rise.

Simulation and optimization of square fin concentric tube heat storage exchanger

The square fin was used to improve the heat transfer rate of the concentric tube phase change heat exchanger. The effects of fin spacing, fin arrangement, and fin length on the melting process of phase change material (PCM) were studied. The influence and mechanism of non-uniform fin arrangement were discussed in detail. The liquid phase distribution and temperature distribution of PCM with time were analyzed. The results indicated that the heat exchanger with square fins can significantly improve the heat storage rate and shortened the complete melting time of PCM. Compared with heat exchangers without fins, the melting time of PCM in a 40 mm equidistant fin heat exchanger was shortened by 15.85%, and that in a 70 mm, non-uniformly spaced fin heat exchanger was shortened by 36.79%. Due to the different distances between the square fins and the outer boundary of the concentric tube, the temperature distribution near the square fin showed anisotropy, which enhanced the melting rate of PCM. The sensitivity order was fin arrangement > fin length > fin spacing. The research results can provide a reference for the design of phase change heat exchangers.

Comparative study on melting and solidification processes of vertical shell-and-tube phase change heat exchanger with an improved conical inner tube

In previous studies, conventional conical structures fail to eliminate the bottom hard-to-melt zone, and assessment of the full cycle thermal performance of melting and solidification processes is lacking. The combination of the improved conical inner tube configuration with the reverse technique has not been reported. Given this, an improved conical inner tube configuration is proposed in this paper to improve melting performance. A two-dimensional numerical model of a thermal energy storage unit with an improved conical inner tube is established. The melting and solidification processes of phase change materials (PCMs) in the unit are numerically simulated to reveal its heat transfer and flow characteristics, and effects of the dimensionless bottom annular distance Sb' and the dimensionless tilt height Ht' of the configuration on the thermal characteristics are emphatically investigated. The results show that the utilization of the improved design effectively promotes the melting rate. However, it deteriorates the heat transfer performance of the solidification process. Therefore, the reverse technique (180° rotation) is adopted to improve the solidification rate. Results indicate that the solidification time of PCMs is remarkably reduced after the reverse layout, with a maximum reduction of 42.63% compared with configurations without reverse. The mode, the improved conical inner tube configuration with reverse layout, is suitable for scenarios where rapid charging is required through full-cycle thermal analysis.

A black box based model for phase change heat exchanger in refrigeration system simulations using Kriging interpolation method

In the present study, a black box model for phase change heat exchangers is developed based on Kriging interpolation. The input and output of the heat exchanger black box model were established based on the mass-flow-guided method. Methods for the input domain determination of are established respectively for the application of system simulation and separate heat exchanger simulation. A training data set sampling method is established based on the Latin hypercube sampling method to achieve significant reduction in sample points while maintaining the integrity of the sample data characteristics. The heat exchanger calculation trend was determined by establishing a regression model; the accurate prediction of heat exchanger performance was achieved by making local corrections to the prediction results through a stochastic distribution process model. Validation results show that, for the condenser model, the average pressure drop prediction error is 0.25%, and the average heat transfer prediction error is 1.18%; for the evaporator model, the average pressure drop prediction error is 0.71%, and the average heat transfer prediction error is 0.80%. The model can achieve high prediction accuracy with a small amount of training data and has a good fitting performance in the range of general applications.

Numerical analysis of pumped two-phase loop: Characterization of steady-state performance

With growing heat dissipation from advanced electronics, two-phase cooling promises effective and unmatched cooling. A pumped two-phase loop (P2PL) can acquire high power and heat flux from the electronics (heat source) and transport and dissipate it to a heat sink with small total thermal resistance at negligible pumping power consumption because of highly effective phase change (boiling and condensation) heat transfer. Owing to many advantages, in recent years, extensive research efforts have been dedicated to understanding fundamental mechanisms of heat and mass transfer in phase change heat exchangers (evaporators or condensers) at a component level. However, there is little work done for an entire two-phase cooling system as a closed loop which is essential to study the system performance characteristics and the contributions/interactions of each component to the system performance. A comprehensive thermal–hydraulic flow network model was developed to study the system performance characteristics. The pressure variation of the P2PL was calculated by considering the compressibility of the vapor volume in the P2PL to account for the effect of the amount of vapor in the system. The numerical results on the thermal and hydraulic performance characteristics of the P2PL for various operating and design parameters – evaporator heat load, mass flow rate, heat sink temperature, and microchannel dimensions – are discussed. It was found that the numerical results match well with the measured steady-state temperature and pressure profiles of the P2PL. The study also highlights the trade-off between the total system thermal resistance reduction and the increased pressure drop (pumping power) with an increase in mass flow rate. It was also found that the microchannels with smaller hydraulic diameters had significant heat transfer enhancement in the evaporator but poor system performance.

Thermoelectric generator for high temperature geothermal anomalies: Experimental development and field operation

In the current climate and energy context, it is important to develop technologies that permit increase the use of renewable sources such as geothermal energy. Enhancing the use of this renewable source is particularly important in some places, due to its availability and the enormous dependence on fossil fuels, as is the case of the Canary Islands. This work proposes the use of thermoelectric generators with heat exchangers working by phase change to transform the heat from the shallow high temperature geothermal anomalies on the island of Lanzarote directly into electricity, since the use of conventional geothermal power plants would not be possible because they would damage the protected environment. To bring this proposal to reality, this work has succeeded in developing and field-installing a geothermal thermoelectric generator that operates without moving parts thanks to its phase-change heat exchangers. This robust generator do not require maintenance nor auxiliary consumption, and produces a minimal environmental impact, it is noiseless, and the use of water as working fluid makes it completely harmless.The developed device consists of a thermosyphon as hot side heat exchanger, thermoelectric modules and cold side heat exchangers also based in phase change. Tests were carried out in the laboratory at various heat source temperatures and varying the number of thermoelectric modules. It was determined that installing more modules decreases the efficiency per module (from 4.83% with 4 modules to 4.59% with 8 modules at a temperature difference between sources of 235 °C), but for the number of modules tested the total power increases, so the field installation was carried out with 8 modules. After the good results in the laboratory, it was satisfactorily installed at Timanfaya National Park (Lanzarote, Spain) in a borehole with gases at 465 °C. This generator presents a maximum output power of 36 W (4.5 W per module), and is generating 286.94 kWh per year, demonstrating the great potential of the developed thermoelectric generators to build a larger-scale renewable installation.

Enhanced behaviour of a passive thermoelectric generator with phase change heat exchangers and radiative cooling

Heat exchangers are essential to optimize the efficiency of Thermoelectric Generators (TEGs), and heat pipes without fans have proven to be an advantageous design as it maintains the characteristic robustness of thermoelectricity, low maintenance and lack of moving parts. However, the efficiency of these heat exchangers decreases under natural convection conditions, reducing their heat transfer capacity and thus thermoelectric power production. This work reports on a novel heat exchanger that combines for the first time, phase change and radiative cooling in a thermoelectric generator to improve its efficiency and increase the production of electrical energy, specially under natural convection. For this, two thermoelectric generators with heat-pipes on their cold sides have been tested: one with the radiative coating and the other without it. Their thermal resistances have been determined and the electric power output was compared under different working conditions, namely, natural convection and forced convection indoors and outdoors. The experimental tests show a clear reduction of the heat exchanger thermal resistance thanks to the radiative coating and consequently, an increase of electric production 8.3 % with outdoor wind velocities of 1 m/s, and up to 54.8 % under free convection conditions. The application of the radiative surface treatment is shown to result in a more stable electrical energy production, suppressing the drastic decrease in the generated electric power that occurs in thermoelectric generators when they work under free convection.

A universal correlation for predicting two-phase frictional pressure drop in horizontal tubes based on machine learning

Accurate prediction of the two-phase frictional pressure drop (FPD) facilitates designing compact phase-change heat exchangers. This study implements ML methods and develops a new universal correlation for predicting FPDs in adiabatic and diabatic flow. A consolidated database with 8663 experimental samples from 64 published literature covering 25 fluids and broad operating conditions is amassed to serve this purpose. The designed ML models, based on artificial neural network (ANN) and extreme gradient boosting (XGBoost) theory, can predict the unknown data with the best mean absolute relative deviate (MARD) of 8.59% and the coefficient of determination (R2) of 0.988 or higher. With the aid of parametric importance analysis conducted by the trained ML models, the obtained key parameters, including vapor quality, dimensionless vapor velocity, Froude number, Bond number, and convection number, are adopted to formulate a new correlation. The new correlations can provide more reliable predictive performance than existing correlations for the consolidated database with a MARD of 24.84%. An excluded database is collected to verify the generality of the correlation, and a lower MARD of 27.47% than existing models is obtained. It demonstrates that ML methods can help develop the universal correlation with improved accuracy and universality.

A stable new composite phase change material based on H2C2O4⋅2H2O-NH4Al(SO4)2⋅12H2O binary eutectic into ZrO2 modified expanded graphite

As energy shortage intensifies, improving energy efficiency and reducing energy consumption have become essential topics. Herein, a form-stable composite phase change material (FCPCM) consisting of modified expanded graphite (MEG) and eutectic hydrate was designed as a reliable and efficient thermal energy storage medium. Firstly, novel binary eutectic hydrate involving oxalic acid dihydrate (H2C2O4.2H2O) and ammonium aluminum sulfate dodecahydrate (NH4Al(SO4)2.12H2O) served as an excellent thermal energy storage guest. Zirconium dioxide (ZrO2) was used as a hydrophilic modifier because of its high heat resistance, high inertness, corrosion resistance, non-toxicity and countless hydrophilic groups. Therefore, the hydrophilic modified expanded graphite (MEG) as a supporting host was constructed by dip-coating of nano ZrO2 sol on the surface of expanded graphite (EG), which improved its hydrophilicity and compatibility with a eutectic guest. Compared with the original EG (83.05°), the contact angle of MEG containing 10 % ZrO2 on the water was decreased to 37.95°. In addition, the adsorption rate and capacity of MEG to binary eutectic were much faster and larger, reaching an approximate saturation (65.58 %) within 40 min, which was three times that of the untreated EG (23.10 %) in the same adsorption time. The resultant FCPCM containing 24 wt% MEG exhibited a good phase transition temperature (54.10 °C), high phase transition enthalpy (168.5 J/g), as well as excellent anti-leakage behavior. After 100 hot and cold cycles, the thermal performances of FCPCM kept relatively stable, which guaranteed its sustained thermal benefits. It provides a potential application in the field of solar phase change heat exchangers.

Field test of a geothermal thermoelectric generator without moving parts on the Hot Dry Rock field of Timanfaya National Park

Although in the last years thermoelectric generators have arisen as a solution to boost geothermal power generation, tests on field are still scarce. The vast majority of the available studies focus on computational simulations or laboratory experiments, mainly with active heat exchangers that require pumps or fans, and, consequently, present moving parts and auxiliary consumption. The present paper demonstrates for the first time the suitability of a geothermal thermoelectric generator (GTEG) with passive phase change heat exchangers, and therefore, without moving parts nor auxiliary consumption, on the shallow Hot Dry Rock (HDR) field of Timanfaya National Park (Canary Islands, Spain), where 173°C air anomalies can be found. The device has been in operation without maintenance for 2 years now, producing more than 520 kWh of energy. In terms of power generation, since the installed device is in turn composed of two prototypes with 10 and 6 thermoelectric modules, it has been confirmed that installing more modules leads to a lower generation per module, although total generation can be higher. In fact, the prototype with 10 thermoelectric modules generated a maximum of 20.9W (2.09 W per module) with a temperature difference between sources of 158°C, while the prototype with 6 thermoelectric modules obtained 16.67W (2.78W per module) under the same conditions. These results open the door for a large-scale exploitation thanks to the intrinsic advantages of modularity, reliability, robustness, and minimal environmental impact of the developed device.

Simulation study on charging performance of the latent energy storage heat exchanger with a novel conical inner tube

The application of a latent heat thermal energy storage (LHTES) system can effectively solve the problem of the mismatch between the energy supply and demand. However, most studies focus on the traditional cylindrical configuration with a low heat storage rate, which limits the wide application of LHTES systems. The configuration optimization of a vertical shell-and-tube LHTES unit is carried out in this paper to enhance heat storage rate, and the effects of cone angle values (0–10°) in the conical shell and conical tube configurations on the heat storage performance are explored by numerical simulations. The results show that these two kinds of conical configurations both significantly improve the melting rate of the phase change material (PCM) compared with the cylindrical unit. However, when the cone angle is the same, the heat transfer enhancement effect of the latter is found to be superior to that of the former. Moreover, the complete melting time is shortened by 46 % as the cone angle of the inner tube increases from 0° to 10°. More importantly, a novel conical tube configuration design is proposed to eliminate the hard-to-melt zone at the bottom of the LHTES unit with the conical tube, then the effects of different tilting heights (60–170 mm) and bottom annulus distances (0–10 mm) are investigated. The results demonstrate that the melting rate increases with the increase in the tilting height, but the increased amplitude of that gradually reduces. Besides, the average heat storage rate shows a trend of first increasing and then decreasing with the increase in the distance of the bottom annulus. When the bottom annulus distance is 2 mm, the average heat storage rate reaches the maximum value, which is 94.84 W. The research results can provide a reference for the engineering design and configuration optimization of the vertical shell-and-tube phase change heat exchanger.