Exchange Equipment Research Articles

Investigation of aerodynamic processes in porous materials based on triply periodic minimal surfaces

RELEVANCE: The relevance of this work lies in the study of new porous materials for use in compact, highly efficient heat exchange devices. PURPOSE: To investigate the hydro-aerodynamic properties of flows passing through porous inserts based on triply periodic minimal surface (TPMS) topologies. To develop a methodology for studying porous materials with ordered structures. To identify potentially suitable TPMS-based porous materials for application in heat exchange equipment. METHODS: Numerical (CFD) and experimental methods were used to address the research objectives. Ansys Fluent 2019 R3 software was utilized for numerical modeling. Experimental samples for the physical experiments conducted on the VENT-08-7LR-01 laboratory setup were fabricated using SLA additive technologies. The porosity of the samples ranged from 0.73 to 0.89. The experiment was conducted with inlet velocities ranging from 0.3 to 4.5 m/s. RESULTS: New empirical dependencies of pressure drop on flow velocity were obtained for inserts based on the surfaces: Primitive (P), Fischer Koch S (FKS), Neovius (N), and Schoen's I-WP (IWP). The airflow through the N structure showed the highest pressure drop, while the P structure had 8 times less pressure drop at the same velocity. Stagnation zones, which can negatively impact heat transfer, were identified in the porous inserts. Changes in local flow velocity in the porous inserts were determined to correlate with the insert's transparency. CONCLUSION: The research results can be used for designing cooling systems with TPMS-based ribbing. Based on the analysis of the velocity vector field distribution and pressure drops, the FKS and IWP structures have potential applications in heat exchange equipment.

Visualization Study on Oil Return Characteristics of Vapor Compression Heat Pump System

Vapor compression heat pump technology is a widely utilized method for energy conversion. Lubricating oil plays a crucial role in the heat pump system cycle by effectively reducing wear on the compressor’s moving parts and preventing refrigerant leakage. However, it can also create an oil film in the heat exchange equipment, which increases thermal resistance and diminishes heat transfer efficiency. This study utilizes a vapor compression heat pump system test bench to investigate factors influencing the system’s oil circulation rate, the two-phase flow patterns of refrigerant and lubricating oil, and the impact of oil circulation on system performance. The findings reveal that as the compressor speed increases, the oil circulation rate initially decreases before increasing again. Additionally, a decrease in the evaporator’s heat load leads to a reduction in oil circulation at high temperatures, while it increases at low temperatures. Furthermore, increasing the opening of the electronic expansion valve results in a gradual decrease in the oil circulation rate, whereas an increase in the refrigerant charge correlates with a rise in the oil circulation rate. The oil return flow pattern can primarily be categorized into three states: slow oil return, oil film flow, and high-speed oil return. These patterns are closely related to the degree of superheat, with lower superheat levels intensifying oil return.

Model of the non-stationary thermal processes in the ground heat pump system

One of the main directions for improving heat supply systems is the tendency to switch to low-temperature heating systems by using heat pump units is the tendency of implementation the low-temperature heating systems based on the use of heat pump units. In the work, the main attention is focused on the improvement of thermal parameters and circuit design features of elements of the heat pump system of heat supply using soil energy. For this purpose, the toolkit of mathematical modelling of processes in ground heat pumps is applied, taking into account the climatic conditions of Ukraine. The paper proves the technical possibility of creating an autonomous system of alternative heat supply for energy-saving technologies with the possibility of using ground energy, taking into account environmental requirements. It is substantiated that the use of the proposed systems is a promising direction for Ukraine, which is experiencing a shortage of its own energy resources, because it provides an opportunity to increase the share of organic fuel substitution and reduce the volume of heat emissions into the environment. A mathematical model of heat processes in the elements of the heat exchange equipment of the heat pump system based on renewable energy (soil energy) and secondary energy (wastewater) was developed, taking into account environmental requirements (preventing hypothermia of the soil during the operation of soil pipes and damage to vegetation, respectively), which allows choosing a rational mode of operation of the system under seasonal climatic changes and technological conditions. Numerical modelling of heat processes in elements of the heat exchange equipment of the heat pump system using groundwater and waste water was performed, and the energy and environmental efficiency of the system under variable climatic and technological factors was determined. Analysis and generalization of the calculation results of the heat pump heat supply systems using alternative energy based on the proposed mathematical model, taking into account environmental requirements (preventing thermal relaxation of the soil) allows to take into account the change in the temperature gradient around the soil heat exchanger and more accurately determine the heat flow from each section of the heat exchanger. It has been established that for heat pumps with soil heat exchangers, the maximum substitution ratio of the traditional fuel is 75 %, and the economically feasible quantity of soil heat exchangers is 9 units. Heat pumps using waste water can completely replace traditional heat supply systems. For individual consumers, it is possible to recommend heat pump units with soil heat exchangers, at the same time, it is necessary to provide a backup source of energy to increase the reliability of heat supply.

Control of deposits on pipeline systems by the method of free oscillations

RELEVANCE. There are a large number of heat exchangers in operation enterprises that operate under various temperature conditions. Steam, hot water, heated products of oil refining and other industries, which may contain oxides of iron, aluminum, calcium sulfate silicates, etc., are used as a heating agent. The efficiency of the heat exchange equipment depends on the condition of the heating surfaces. Contamination of these surfaces with various deposits dramatically reduces the heat transfer coefficient, which leads to a significant increase in heat consumption. The nature of the deposits depends on the properties of the heating agent and the heated medium.THE PURPOSE. The purpose is to assess the possibility of controlling deposits on the surfaces of heat exchange equipment by the free oscillation method. The presence of deposits changes the mass of structures and, consequently, the natural frequencies of vibrations, the analysis of which can determine not only the presence and thickness of deposits, as well as their appearance.METHODS. The paper shows the results of experimental studies conducted using a hardware and software package and calculations of natural vibrations of the surfaces of heat exchange equipment in the ANSYS software package to identify their dependence on the thickness and density of deposits. A plate, a pipe, and a pressurized pipe were modeled as heat transfer surfaces.RESULTS. The results obtained experimentally and computationally coincided, and it was concluded that the free oscillation method makes it possible to determine not only the presence of deposits on heat exchange surfaces, but their thickness and appearance.CONCLUSION. The free oscillation method can detect deposits in a timely manner and monitor their condition, which in turn will, reduce overall operating costs, increase energy efficiency and extend service life.

The Influence of Gas-Dynamic Non-Stationarity of Air Flow on the Heat Transfer Coefficient in Round and Triangular Straight Pipes with Different Turbulence Intensities

Unsteady gas-dynamic phenomena in pipelines of complex configuration are widespread in heat exchange and power equipment. Therefore, studying the heat transfer level of pulsating air flows in round and triangular pipes with different turbulence intensities is a relevant and significant task for the development of science and technology. The studies were conducted on a laboratory stand based on the thermal anemometry method and an automated system for collecting and processing experimental data. Rectilinear round and triangular pipes with identical cross-sectional areas were used in the work. Flow pulsations from 3 to 15.8 Hz were generated by means of a rotating flap. The turbulence intensity (TI) of the pulsating flows varied from 0.03 to 0.15 by installing stationary flat turbulators. The working medium was air with a temperature of 22 ± 1 °C moving at a speed from 5 to 75 m/s. It was established that the presence of gas-dynamic unsteadiness leads to an increase in the TI by 47–72% in a round pipe and by 36–86% in a triangular pipe. The presence of gas-dynamic unsteadiness causes a heat transfer intensification in a round pipe by 26–35.5% and by 24–36% in a triangular pipe. It was shown that a significant increase in the TI of pulsating flows leads to an increase in the heat transfer coefficient by 11–16% in a round pipe and a decrease in the heat transfer coefficient by 7–24% in a triangular pipe. The obtained results can be used in the design of heat exchangers and gas exchange systems in power machines, as well as in the creation of devices and apparatuses of pulse action.

Integrating smart manufacturing techniques into undergraduate education: A case study with heat exchanger

The process systems domain is undergoing the fourth industrial revolution, which is helping industries digitize and optimize their production techniques. Concurrently, the field of data-based modeling has been expanding, leading to the proposal of many fault detection models. However, the rapid expansion has created gaps in the field. For instance, Smart Manufacturing (SM) methodologies have yet to be incorporated into undergraduate chemical engineering education. Additionally, only a few developed fault detection models have been deployed for real-time usage and practical applications. This study takes a crucial step toward bridging the two mentioned gaps by enabling undergraduate students to learn SM techniques and developing a safe and controlled academic environment for deploying fault detection models. The demonstration is implemented on a shell and tube heat exchanger, taught in a senior year laboratory course, using the Smart Manufacturing Innovation Platform (SMIP). The implementation provides an easily customizable pipeline for SM applications involving human-in-the-loop decision-making on a real-life hardware system. Actual data from heat exchanger equipment is used to train and compare the performances of several state-of-the-art fault detection models, including fully connected, convolutional, and recurrent neural networks. Current work also presents tutorials on deploying models for practical real-time applications using the SMIP. The overall architecture is a plug-and-play package that will motivate students to learn about SM and catalyze their interest in developing and deploying fault detection models using real-world data.

Inventory of Electronic Waste (E-Waste) and Residues in Junkshops: A Step Towards Residual Waste Management

The improper management of Waste Electrical and Electronic Equipment (WEEE) constitutes a critical global environmental challenge, with a significant proportion of e-waste ending up in landfills, posing substantial ecological and health risks. In the Philippines, particularly in areas like Marilao and Bulacan, many individuals rely on the recycling of e-waste for their livelihoods, primarily through junkshops and informal recycling networks. Despite providing economic benefits, these practices often result in substantial residual waste, exacerbating landfill overflow and environmental degradation. This study aims to establish a detailed e-waste inventory and propose practical strategies for improving residual waste management. This research used a mixed-method approach to collect data via surveys, interviews, and direct observations at selected junkshops in Marilao. The findings enabled a comprehensive categorization of e-waste based on economic value, highlighting "temperature exchange equipment" as the most economically valuable category while identifying "small IT and telecommunication equipment" as the least. Among the significant residual wastes identified were base/black plastics, styrofoam, and glass, which are commonly mishandled. The study proposes several management strategies, including partnerships with local governmental bodies and recycling companies to enhance recycling processes, improving dismantling techniques to reduce waste, and implementing rigorous waste segregation practices to prevent contamination and improve recycling rates. This expansion is critical for a more comprehensive understanding and monitoring of e-waste management practices, facilitating the development of more effective and sustainable waste management solutions. By adopting these strategies, junkshops and informal recyclers can optimize e-waste management, reducing environmental impact while maintaining economic viability.

Heat transfer and visualization of flow boiling on nanowire surfaces in the microchannel

Enhancing heat transfer efficiency is crucial in heat exchange equipment. Although previous studies have focused on developing micro/nano-structured surfaces, further exploration into how surface structure can improve heat transfer efficiency (H) by altering bubble dynamics is still needed. This study aimed to innovatively analyze the impact of titanium carbide (TiC) nanowire heights—specifically 4 µm and 12 µm—on boiling heat transfer performance. Conducted under varying heat flux (Q) (50–200 W/m2) and mass flux (G) (200–300 kg/m2·s), our experiments assessed H, pressure drop (P), and local boiling curves. Using a high-speed camera, we observed complex periodic flow patterns on the 4 µm nanowire surface, including elongated bubble formation, expansion, local dryout, and subsequent fluid rewetting. Results showed that the 12 µm nanowire surface increased H by up to 19.84 % in single-phase conditions, while the 4 µm nanowire surface increased H by up to 27.9 % in two-phase conditions. These findings highlight the significant role of nanowire length and arrangement in optimizing boiling heat transfer performance. This work lays a foundation for further investigations into diverse nanowire materials and configurations.

Weight and size characteristics of heat exchange equipment of hybrid Flash/ORC power plants: case of application in WHR cogeneration plants

Weight and size characteristics of heat exchange equipment of hybrid Flash/ORC power plants: case of application in WHR cogeneration plants

Influence of shielding gas flow on the TIG welding process using stainless steel 304 material

A common issue encountered with main heat exchanger equipment is improper operation, which can lead to the development of cracks in the stainless-steel pipes. The welding process alters the metal microstructure in the heat-affected zone, thereby affecting the mechanical properties of the welded joint. To mitigate this issue, TIG welding with argon shielding gas is employed. This method helps prevent oxidation and ensures the formation of a stable welding arc in 304 stainless steel, which is renowned for its excellent mechanical properties and corrosion resistance. The objective of this study is to evaluate the impact of variations in shielding gas flow on the mechanical properties of 304 stainless steel plates during the TIG welding process. The aim is to determine the optimal settings for producing robust and long-lasting welded joints. To assess the hardness of the welded joints, we employed a Brinell-type Hardness Tester FB-3000LC machine. A Brinell steel ball indenter measuring 5 mm on the HBW scale and applying a load of 125 Kgf was utilized. At a protective gas flow rate of 8 L/min, the average tensile stress was 44.72 N/mm², strain was 0.177, modulus of elasticity was 2518 MPa, and hardness was 99.712 HBW. Increasing the gas flow rate to 13 L/min resulted in an average tensile stress of 47.50 N/mm², strain of 0.189, elastic modulus of 2525 MPa, and hardness of 105.522 HBW. Further increasing the gas flow rate to 18 L/min led to an average tensile stress of 49.69 N/mm², strain of 0.192, modulus of elasticity of 2597 MPa, and hardness of 106.704 HBW. Based on the research findings, it was observed that the weld area exhibited an increase in hardness values due to the heat generated during the welding process. The use of protective gas flow during welding is deemed effective in producing well-formed welded joints, as it prevents fractures from occurring within the weld area during the tensile test process. The choice of protective gas is determined by the dimensions of the material plate.

ПРИНЦИПЫ СОЗДАНИЯ ДИСКРЕТНЫХ ПРОТЕКТОРНЫХ ПОКРЫТИЙ ДЛЯ ТЕПЛООБМЕННЫХ ПОВЕРХНОСТЕЙ

The paper proposes the principles of creating discrete tread coatings for heat exchange surfaces. Protective metallized coatings allow you to protect heat exchange equipment from corrosion and in-crease its service life

IMPROVEMENT OF THE METHODOLOGY FOR CALCULATING THE HYDRODYNAMICS OF COILED HEAT EXCHANGERS FOR CRYOGENIC PLANTS OPERATING ON THE J-T CYCLE

The widespread use of cryogenic plants operating on the J-T (Joule-Thomson) cycle is associated with low operating costs, reliability, and long service life. One of the main elements of the plant is a recuperative heat exchanger made in the form of a single- or multi-layer coiled heat exchange surface. The ability to compensate for temperature and mechanical stresses due to the twisted design ensures long-term and trouble-free operation of the heat exchange equipment. The importance of determining the characteristics of the hydrodynamics of the flow of liquids or gases is primarily associated with a conscious choice of methods for solving heat and mass transfer problems, the use of certain methods of process intensification, and optimization of equipment design. The purpose of creating efficient equipment is to determine the maximum heat transfer rate at moderate values of hydraulic resistance. The analysis of known empirical dependencies does not provide a definitive answer regarding the development of a generalized methodology for calculating Hampson-type microheat exchangers used in cryogenic installations. The aim of this work is to improve the methodology for calculating the hydrodynamics of coiled heat exchangers by modifying the calculated correlations. This is possible by introducing appropriate corrections to them that take into account the influence of the geometric characteristics of the tube bundle on its resistance. The experimental study of hydrodynamic processes during forced gas convection in a coiled heat exchanger made it possible to establish the dependence of the Euler number Eu on the main geometric characteristics of the heat exchanger: the relative coil pitch, the gap between the heat exchanger tube and the outer and inner surfaces of the body. Based on the research results, the corrections in the dimensionless form eкр and eз, which are used to perform variational calculations of the structures of coiled heat exchangers located in annular channels, were determined in order to optimize their geometric characteristics. Bibl. 19, Fig. 5.

Research of boiling flow parameters in vertical evaporators of marine refrigeration machines

In this work, the subject of research is hydrodynamics, and in particular, the hydraulic resistance of a boiling two-phase flow moving in vertical and inclined pipes of evaporators of ship refrigeration units. Such movement is typical for various types of industrial heat exchange equipment, including the development of promising types of evaporators, for example, vertical devices for ships in which in-tube boiling of liquid refrigerant occurs. Experiments were carried out to study hydraulic resistance in vertical pipes with different channel diameters and lengths. The main dependencies of the various components of hydraulic resistance that arise during the movement of a boiling two-phase flow are presented. Based on the data obtained, the prospects of transitioning ship evaporators of refrigeration units to a vertical arrangement of heat exchange tubes are shown. When applied to ship refrigeration machines, we can say that the transition to vertical units has its advantages, primarily in reducing pressure losses. The resulting set of data allows us to recommend the design of vertical evaporators for auxiliary ship installations.

Fouling and Corrosion Behavior of Nickel–Graphene/Polytetrafluoroethylene Composite Hydrophobic Coating

Fouling and corrosion mitigation in heat exchange equipment remains a significant challenge. Numerous research techniques have been developed to address this issue. Surface modification is an effective method for preventing fouling and corrosion. This work used electrodeposition and dip coating techniques to create a nickel–graphene/polytetrafluoroethylene (NGP) composite hydrophobic coating. The field emission scanning electron microscopy, contact angle analyzer, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, and atomic force microscopy techniques were used to investigate the surface morphologies, wettability, binding energies, chemical compositions, and roughness, respectively. The water contact angle (WCA) of the NGP hydrophobic coating (147.1° ± 2.2°) was significantly higher than the WCA of carbon steel (76.8° ± 1.6°). Electrochemical impendence spectroscopy results showed that the NGP composite hydrophobic coating has improved anti-corrosion performance with a greater capacitive curve, a higher modulus of impedance value at low frequency, and increased charge transfer resistance. Furthermore, fouling testing at various temperatures exhibited the anti-fouling and anti-corrosion behavior of the NGP composite hydrophobic coating, suggesting possible uses in practical applications.

Study on Conventional Island Retrofit Strategies for Converting Coal-Fired Power Plants to Nuclear Power Stations in China

The conversion of coal-fired power plants to nuclear power stations is a potential method for decarbonizing coal power and offers a pathway for low-carbon development in China’s power industry. This paper focuses on retrofitting China’s coastal coal-fired power stations and compares the potential nuclear reactor technologies for the retrofit: China’s mainstream pressurized water reactor and the commercially operated fourth-generation high-temperature gas-cooled reactor (HTGR). The analysis compares the degree of matching between the two technologies and coal-fired power stations in terms of unit capacity, thermal system parameters, unit speed, structural dimensions, and weight, which significantly impact the retrofit scheme. The results indicate that HTGR is more compatible with coal-fired power plants and is recommended as the type of nuclear reactor technology to be retrofitted. The study selected the 210 MWe High-Temperature Gas-Cooled Reactor Pebble-Bed Module (HTR-PM) as the reactor technology for retrofitting a typical 300 MW class subcritical coal-fired unit. Based on the concept of subcritical parameters upgrading, the potential analysis and strategy study of retrofit is carried out in terms of the turbine, the main heat exchange equipment, the main pumps, and the main thermal system pipelines in the conventional island. The results indicate that the conventional island of the HTR-PM nuclear power plant has significant potential for retrofitting, which can be a crucial research direction for nuclear retrofitting of coal-fired power plants.

Design and analysis of steam methane reforming hydrogen liquefaction and waste heat recovery system based on liquefied natural gas cold energy

To improve the utilization rate of liquefied natural gas (LNG) cold energy, reduce hydrogen (H2) liquefaction cost, recover waste heat and reduce carbon dioxide (CO2) emission, this study designs a steam methane reforming (SMR) H2 liquefaction and waste heat recovery system based on LNG cold energy for the production of 10 tons of liquid hydrogen (LH2) per day. Parameters analyses and optimization, exergy analyses and economic analyses of the system are carried out and compared with other H2 liquefaction systems. The results show that: under the optimal conditions, the values of specific energy consumption (SEC), coefficient of performance (COP) and exergy efficiency (ƞex) were 5.93 kWh/kg LH2, 0.2225 and 53.24%, respectively. Exergy losses of system is mainly distributed in heat exchange equipment and compressors. Decreasing the heat exchange equipment cold and heat sources inlet temperature difference and reducing the compressors compression ratio were beneficial to reduce equipment exergy losses. The pre-cooling performance of LNG is better than that of liquid nitrogen (LN2) and mixed refrigerant (MR). Compared with the pre-cooling H2 liquefaction system without waste heat recovery, the SEC decreased by 0.26 kWh/kg LH2 and ƞex increased by 2.28%. Research results are conducive to resource conservation and environmental protection.

Comprehensive evaluation on deposition and heat transfer performance of the mixed tube bundle based on orthogonal experimental study

Deposition on heat exchange surfaces is an urgent problem to be solved to achieve efficient utilization of energy in thermal equipment. To mitigate deposition and the resultant heat attenuation, this work proposes a mixed tube bundle strategy of inserting attached cylinders behind the tube bundle, which can effectively meet the design requirements of high anti-deposition performance, high heat transfer efficiency, and low flow resistance. An integrated dynamic model for deposition is developed to elucidate the effect of ash particles on deposition, flow, and heat transfer characteristics. Based on the inverse distance weighting interpolation, a dynamic mesh smoothing technique is employed to simulate the evolving deposition layer on the heat transfer surface. In addition, the L16(43) orthogonal experimental design method is adopted to study the influence of the arrangement angle, diameter, and distance to the primary bundle of the attached cylinder on the overall performance, and determine the optimal scheme. The results show that deposition in the cases using the mixed tube bundle strategy has significantly decreased. The weakening effects of the attached cylinder on the deposition of small-medium particles and large-sized particles are due to the inhibition of vortex development in the gap of tube bundle and the deviation of the motion trajectory, respectively. The novel design exhibits the lowest deposition mass Mdep = 1.12 g and the best comprehensive performance PEC = 1.14 under the condition of the arrangement angle of 50°, the diameter of 10 mm, and the distance between the primary bundle of 5 mm. The obtained results can provide reference schemes and guidance for the optimization of the design of heat exchange equipment and accessory devices.

MASSTRANSFER FEATURES IN THE APPARATUSES WITH A MOVING NOZZLE IN A THREE-PHASE FOAM LAYER

The improvement of heat and mass exchange equipment for sorption processes in the countercurrent contact of gas and liquid in combined block elements with a weighted spherical nozzle, as well as a more in-depth study of this process, is an urgent task of chemical technology. A fundamentally new type of ball-shaped three-dimensional mesh fluidized nozzle was developed and researched, the bodies of which are made of polymer layers with holes, and a freely coiled metal or polymer mesh is located inside. The nozzle has a high specific surface area, developed free volume and low bulk density. The study of mass transfer in the liquid and gas phases was carried out and the corresponding calculation equations were obtained. Dependencies for the calculation of the mass transfer coefficients and the efficiency of the combined block element on the mode and design parameters are established. The results of calculations based on the obtained dependencies show a sufficient correlation with the experimental data. The proposed model of the desorption process of carbon dioxide from water, which allows predicting the values of the efficiency indicators of the decarbonization process. It was established that the use of a combined block element with a ball-shaped nozzle allows to increase the mass transfer coefficients compared to the failure plate. The industrial implementation of absorption processes in the foam layer and the use of the gas-liquid layer stabilization method significantly expands the scope of application of foam apparatuses and opens up new opportunities for intensifying technological processes. Previously expressed assumption about the perspective of using mesh materials for the manufacture of nozzle bodies was confirmed by experiments, but the peculiarity of the operation of devices with similar nozzles should be emphasized.

Nanodiamond Coating in Energy and Engineering Fields: Synthesis Methods, Characteristics, and Applications.

Nanodiamonds are metastable allotropes of carbon. Based on their high hardness, chemical inertness, high thermal conductivity, and wide bandgap, nanodiamonds are widely used in energy and engineering applications in the form of coatings, such as mechanical processing, nuclear engineering, semiconductors, etc., particularly focusing on the reinforcement in mechanical performance, corrosion resistance, heat transfer, and electrical behavior. In mechanical performance, nanodiamond coatings can elevate hardness and wear resistance, improve the efficiency of mechanical components, and concomitantly reduce friction, diminish maintenance costs, particularly under high-load conditions. Concerning chemical inertness and corrosion resistance, nanodiamond coatings are gradually becoming the preferred manufacturing material or surface modification material for equipment in harsh environments. As for heat transfer, the extremely high coefficient of thermal conductivity of nanodiamond coatings makes them one of the main surface modification materials for heat exchange equipment. The increase of nucleation sites results in excellent performance of nanodiamond coatings during the boiling heat transfer stage. Additionally, concerning electrical properties, nanodiamond coatings elevate the efficiency of solar cells and fuel cells, and great performance in electrochemical and electrocatalytic is found. This article will briefly describe the application and mechanism analysis of nanodiamonds in the above-mentionedfields.

Thermodynamic analysis of liquid air energy storage system integrating LNG cold energy

Liquid air energy storage (LAES) presents a promising solution to effectively manage intermittent renewable energy and optimize power grid peaking. This paper introduces a LAES system integrating LNG cold energy to flexibly manage power peaking, including intermediate energy storage, power generation using organic Rankine cycle, multi-stage direct expansion, and solar energy for heating. Aiming to maximize the electrical round-trip efficiency, a genetic algorithm is employed to optimize the operational parameters of the proposed LAES system. The results indicate that the combined design of cold energy utilization, multi-stage direct expansion and solar heating for proposed LAES system significantly improve the power performance, achieving an energy capacity of 0.125 kWh/kgLNG and an electrical round-trip efficiency of 376.7 %. The exergy losses of heat exchange equipment are far larger than mechanical equipment in the LAES system, so the optimization design of heat exchange equipment is preferred to improve the exergy performance. The proposed system achieves both high efficiency and flexibility and hence contributes to the development of liquid air energy storage systems.