Ice storage system Research Papers (original) (raw)

2025

A numerical investigation on a latent heat thermal energy storage system based on a PCM is accomplished. The PCM used is paraffin wax having a melting process over a range of temperature and a high value of latent heat. A metal foam is employed to improve the thermal conductivity of the PCM. The geometry of the system under investigation is an enclosure with foam and tubes. The internal surface of the tubes are assumed at a constant temperature above the melting temperature of the PCM to simulate the heat transfer from a hot fluid. The external surfaces of the enclosure are assumed adiabatic or with heat losses toward the external ambient. The phase change of PCM is modelled with the enthalpy-porosity theory while the metal foam is modelled like a porous media using the Darcy-Forchheimer law. Local thermal non-equilibrium (LTNE) model is assumed. The results are presented in term of melting time and temperature field for the charging process. Different porosities are investigated at...

2024, International Communications in Heat and Mass Transfer

Heat storage systems are used as a method for transferring and controlling the cold load in hot seasons. In this paper, to analyze the phase changes of an ice-on-coil thermal storage tank, the process of ice formation in a cavity with refrigerant carrier tubes is carried out using numerical simulation. Moreover, performance of some heat transfer enhancement methods including usage of fins around tubes with various dimensions and numbers and various tube number and arrangement, are compared. In this study, the inlet temperature is considered to be 275 K, which the temperature decrease up to 10 K due to freezing is observed. According to the results, the fin height is a very effective parameter in increasing the freezing rate. Also, upon increasing the tube number with smaller diameter, ice is formed with a higher speed due to their uniform distribution. So, with the tube number increasing from 9 to 16 in these systems at the same time interval, the fluid temperature drops from about 275 to 269 K, as well as the volume fraction of liquid decrease from about 0.4 to 0.22. Finally, by changing the tube arrangement from rectangular to triangular, faster rate of ice formation are observed.

2024, International Communications in Heat and Mass Transfer

2024, arXiv (Cornell University)

In this paper, a 3D conjugated heat transfer model for Nano-Encapsulated Phase Change Materials (NEPCMs) cooled Micro Pin Fin Heat Sink (MPFHS) is presented. The governing equations of flow and heat transfer are solved using a finite volume method based on collocated grid and the results are validated with the available data reported in the literature. The effect of nanoparticles volume fraction (C = 0.1, 0.2, 0.3), inlet velocity (Vin = 0.015, 0.030, 0.045 m/s), and bottom wall temperature (Twall = 299.15, 303.15, 315.15, 350.15 K) are studied on Nusselt and Euler numbers as well as temperature contours in the system. The results indicate that significant heat transfer enhancement is achieved when using NEPCM slurry as an advanced coolant. The maximum Nusselt number when NEPCM slurry (C = 0.3) with Vin = 0.015, 0.030, 0.045 (m/s) is employed, are 2.27, 1.81, 1.56 times higher than the ones with base fluid, respectively. However, with increasing bottom wall temperature, the Nusselt number first increases then decreases. The former is due to higher heat transfer capability of coolant at temperatures over the melting range of PCM particles due to partial melting of nanoparticles in this range. While, the latter phenomena is due 1 Corresponding Author. 2 to the lower capability of NEPCM particles and consequently coolant in absorbing heat at coolant temperatures higher than the temperature correspond to fully melted NEPCM. It was observed that NEPCM slurry has a drastic effect on Euler number, and with increasing volume fraction and decreasing inlet velocity, the Euler number increases accordingly.

2024, Journal of advanced thermal science research

In this study, a modified direct current compressor (MDC) is tested experimentally. The experimental study is conducted in order to observe the performance of a solar energy powered MDC. Then, the performance of this MDC is compared with brand new direct current compressors (BNDC) in the market. The experimental setup has a mini fridge with 50 liters capacity, a photovoltaic panel, a battery, a charge regulator and measurement equipments. Also, a pyranometer is used to define solar radiation on the photovoltaic panel. Experiments are conducted for various cabinet loads such as no storage items, low, nominal and over load at steady state condition.

2024, UKH Journal of Science and Engineering

The Iraqi Kurdistan region has significant potential for implementing solar energy with an average annual rate of 5.245 kWh/m2. However, most of its energy supply currently comes from nonrenewable energy sources. With the continually increasing demand for energy, an alternative energy-generation technique is required. Among the various renewable energy resources, generating electricity directly from sunlight is the best option because it can be applied by the average household and is environmentally friendly. In this study, a cost and environmental analysis for a 10 kW grid-connected photovoltaic system is presented for a government building with the aim of reducing the load demand on the grid during weekdays and also to inject the generated power into the power grid during weekends. A simulation of the proposed PV system was generated by using Photovoltaic Geographic Information System software to estimate the system’s production performance. The software showed that the highest en...

2024, Applied Thermal Engineering

to 6, the melting time decreases. The unsteady numerical simulations support the prediction of the theoretical model. Thus, in the here studied geometrical configurations the proposed approach represents a simplified and accurate design... more

2024

The aim of this study is to develop a measurement method to determine the solidification front in a thermal energy storage unit. The electrical conductivity of a phase change material (PCM) changes dramatically in solidification/melting process and the proposed measurement method is based on observation of electrical conductivity of PCM. This system utilizes a microprocessor and a multiplexer unit to observe medium via multiple nodes. The experimental results show that the accuracy of this method is nearly 3%, in comparison with the traditional photography method. The most important advantages of this method are elimination of the heat gain, caused by opening a cover in the insulation at specific time periods, compared to the with photography method and ease of observation of solidification fronts electronically which results wider application area where photography method cannot be exploited.

2023, Solar Energy

Photovoltaic (PV) solar refrigeration system is considered as one of the most vital areas in photovoltaic application. This research work aims to study the effect of operating pressures of evaporator and condenser to the performance of directly coupled variable speed solar refrigeration system. Performance parameters which were considered in the study are compressor speed, power consumption, refrigerant mass flow rate, and cooling capacity. The working pressure of the refrigeration system at evaporator and condenser were expressed with the saturation temperatures. In this study, a sensitivity analysis was performed with two cases. In the first case, the working saturation temperature of the condenser was fixed to 49 • C while the working saturation temperature of the evaporator was varied from − 13 • C to − 34 • C. In the second case, the saturation temperature of the evaporator was fixed to − 24 • C while the saturation temperature of the condenser was varied from 38 • C to 60 • C. In the first case, it was found that all the considered performance parameters were sensitive to variation in saturation temperature of the evaporator. In the second case, compressor speed and power consumption showed negligible sensitivity to variation in saturation temperature of condenser but the other two performance parameters (refrigerant mass flow rate and cooling capacity) showed significant sensitivity to variation in saturation temperature of condenser.

2023, Energy Engineering

Solar energy applications could be the best alternative to the conventional fuels for the purposes of domestic, water and space heating and some industries in the sunny, arid, and hot areas. In the present study, the performance of an evacuated tube solar heater for water heating for months of February and March was experimentally investigated. This was performed in a hot and arid area (Nasiriya City, South of Iraq). A solar heater with ten evacuated tube solar collectors with a capacity of 100 liter was used in the experiments. Each evacuated tube had a length of 1.8 m with an outside diameter of 8 cm. It was observed that for the two selected months, water temperature of the solar heater reached a maximum more than 70°C during sunny days with no heat extraction from the tank of the solar heater. Moreover, heat was extracted from the solar collector with four different flowrates 0.5, 0.75, 1, and 1.25 l/min, respectively. The results showed that temperature of the solar heater behaved differently from the static situation. When the heat extraction begun, there was a gradual and noticeable decrease in the water temperature of the heater. The observed decrease was slight with the lowest flowrate (0.25 l/m) and becomes sharp with the highest flowrate (1.25 l/min). However, water temperature of the solar heater remained higher than 40°C for the investigated flowrates except the case of 1.25 l/min. The results showed that evacuated tube solar heater can work efficiently in arid and hot areas in winter and spring seasons when the conditions of solar radiation are suitable.

2023

2023, Applied and Computational Mechanics

The problems of heat and mass transfer in phase change materials are of great engineering interest. The absorption and storage of energy in the form of latent heat makes it possible to use them in the construction industry to smooth out the effects of temperature transitions in the environment. This work is devoted to the study of heat transfer in a building block with paraffin inserts under unsteady external conditions. The influence of the geometric dimensions of the block and the volume fraction of the phase change material on the effect of restraining external temperature fluctuations was studied. The unsteady conjugate melting problem was solved in a closed rectangular region with two cavities filled with PCM. The temperature of the environment on the left boundary changes in harmonic law. Thermal distributions were obtained at various points in time.

2023, Renewable Energy

As far as there is concern with the supply and demand of energy, thermal energy storage becomes critical for the efficiency enhancement of all solar thermal energy systems. On the other hand, latent heat storage has been located in the middle of attractions by different applications because of its high energy capacity, specifically without changing in the temperature. The exact analysis of problems that deal with solar thermal collectors is not easy due to their non-linear nature; therefore, numerical solutions should be employed. In the current paper, it is tried to review the most recent numerical studies on solar thermal collectors operated with Phase Change Materials (PCMs) by considering the effects of adding solid nanoparticles and applying different fins as appropriate techniques for energy efficiency improvement. The published articles show that using nanoparticles and fins along with PCMs affect the performance of solar collectors significantly. In addition, challenges and directions for future research in this area are presented and discussed. Regarding to the new generation of solar collectors, which is called as fourth generation, use of heat pipes integrated with nano-PCMs is an excellent idea for future work. Keywords c p Specific heat (KJ Kg-1 K-1) ps c Specific heat of solid (KJ Kg-1 K-1) pl c Specific heat of liquid (KJ Kg-1 K-1) d Length of fin (m) D Fin half thickness (m)

2023

This paper presents the development and evaluation of a prototype refrigerated cooling table for conference services. The major components of the table are compressor, condenser, evaporator, capilary tube, thermostat and table metal wooden frame. The table uses vapour compression cycle based on the Evans-Perkins (reverse Rankine) cycle as its principle of operation. The evaporator has three cabinet ports. Plywood and square mild steel pipes are used for the construction of the table frame. The refrigerated cooling table successfully reduces temperature of beverages from 35°C to 15.5°C, 13°C and 11°C, when placed in a plastic, glass and stainless steel containers respectively. The refrigerated cooling table performs better when compared with a standard domestic refrigerator. The coefficient of performance using experimental values is 5.14 with a compressor power of 69.3W for three participants. 1. Introduction Refrigeration, during the Stone Age era, was known to the ancient Egyptians and people of India who used evaporation to cool liquid in porous earthen jars exposed to dry night air and to the early Chinese, Greek and Romans who use natural ice or snow stored in underground pits for cooling wine and other delicacies. The technique of mechanical refrigeration began with the invention of machine for making artificial ice. The first known artificial refrigeration was demonstrated by William Cullen at the University of Glasgow in 1748. Cullen let ethyl ether boil into partial vacuum; he did not however use the result to a practical purpose. In 1805, an American inventor, Oliver Evans designed the first refrigeration machine that used vapour instead of liquid. Evans never constructed his machine, but a similar one was built by an American physician, John Gorrie in 1844. Commercial refrigeration is believed to have been initiated by an American businessman, Alexander twinning in 1856. Shortly afterwards, an Australian, James Harrison examined the refrigerators used by Gorrie and Twinning and introduced vapour compression refrigeration to the brewing and meat packing industries. In 1884, Dr. John Gorrie designed the first commercial reciprocating refrigerating machine in the United States. The first hermetically sealed motor-compressor was developed by General Electric Company for domestic refrigerators and sold in 1924. The most outstanding developments in refrigeration was achieved when two refrigeration engineers, Midgely and Hene discover a nontoxic, non-flammable, fluorinated hydrocarbon refrigerant family called Freon in 1931. The chlorofluorocarbons (CFCs), Refrigerant-11 and refrigerant-12, became widely adopted commercial products in reciprocating and centrifugal compressors [1, 2]. However, due to the depletion of the ozone layer, the introduction of hydrofluorocarbons (HFCs) is gradually gaining grounds due to its non-ozone depleting substances. HFC-134a is a synthetic substance and has emerged as an alternative to Freon-12 [1]. The applications of refrigeration include, but not limited to household (domestic) refrigerators, industrial freezers, cryogenics, air conditioning and heat pumps [3]. In developing tropical countries like Nigeria, the use of refrigeration as a domestic refrigerators are the most prevalent due to very high temperatures. Domestic refrigerators are use for chilling beverages at homes, offices, seminars, cocktail parties, general meetings, canteens and conferences. However, during general meetings and conferences where participants are expected to be seated for a very long time, the beverage served loses its heat to the environment, causing it to reduce its palatability. To make it chilled again, the beverages are returned to the refrigerator distant away from the participants and left for several minutes before returning it to the participants. This practice of taking beverages away from the participant in some cases opened is unhygienic and unsafe. To circumvent this problem, Mohammed et al. [4] designed an innovative refrigerated cooling table to be used for conference services. This paper presents the development and evaluation of a portable cooling table for conference services. The table is another innovative use of the principle of refrigeration. It is a multipurpose table which fulfils the

2023, Indonesian Journal of Electrical Engineering and Computer Science

In this paper, the effect of the ambient temperature on the PV modules for different angles of inclinations and different intensities of the solar radiation on the surface of the PV module is considered by using empirical correlations for natural convection. An analytical model based on the energy balance equilibrium between the PV module and the environment conditions has been used. Also an expression for calculating the electric power of silicon PV modules in a function of the ambient temperature, the intensity of the solar radiation, the incident angle of the solar radiation to the surface of the PV module and the efficiency of the PV modules at STC conditions have been used. By comparing the obtained both results, it can be seen that the largest deviation between the power values obtained by the analytical model and expression is about (5 %). The results obtained indicates that in the case of a small number of PV modules corresponding to the required number for an average househ...

2023, Annales de Chimie - Science des Matériaux

This paper investigates the effect of fins orientations of a horizontal two fins annular tube heat exchanger on enhancing the heat transfer during the melting process of n-eicosane, as phase change material (PCM) used in thermal storage systems. Based on the enthalpy-porosity method, two-dimensional model is performed and solved by Ansys Fluent. The impact of the fins orientation on melting rate, thermal conduction and natural convection, as the angle of the system varied from 0º (vertical fins) to 90º (horizontal fins) are discussed. Numerical predictions are validated by comparison with experimental data and numerical results reported in the literature. Good agreements are achieved. The results show that at initial time of the melting process, the conduction heat transfer is dominant. During the melting process, the heat transfer in the horizontal fins is more effective while the upper half of PCM melts and less effective as the lower half of PCM melts because fin arrangement resi...

2023, Journal of Renewable Energies

In this paper, the melting and solidification of n-eicosane as a PCM inside two orientations of square containers is investigated numerically, using enthalpy–porosity method. The study reveals how the melting and solidification rate could be affected by changing the orientation of the phase change material container with a constant temperature boundary. It was found that the orientation of the square cavity has a significant effect on the melting and solidification rate of a PCM, the improvement is more than 40% for both cycles. Therefore the orientation of the heat exchange surface is a good control parameter for both the solidification and melting process

2023, Journal of Energy Storage

Freezing of paraffin through a channel of air conditioning system was simulated in present study by means of finite volume approach. The sinusoidal air gaps have been imposed within the PCM (phase change material) zone. With inclusion of nanoparticles within RT28, the thermal features have been improved and for estimating the properties, single phase based formulations have been incorporated. The air zone has turbulent regime (Re = 2000 to 3000) and k-ε technique was applied while paraffin zone was laminar. The impact of gravity has been ignored in freezing process and implicit approach for discretization of unsteady terms has been applied. Two levels for fraction of nano-powders and inlet temperature of air have been involved in simulations. The freezing time reduces by 4.58 % with using nanoparticles which is associated with higher conductivity of NEPCM. With reduction of temperature of inlet flow, the solidification time reduces about 27.6 %. With rise of Re from 2e3 to 2.5e3 and 3e3, the freezing rate enhances around 14.3 % and 11.93 %.

2022

B.Koteswararao K. Radha krishna P.Vijay 3 N.Raja surya Assistant Professor, Department of Mechanical Engineering, K L University, Guntur, India-522502 Assistant Professor, Department of Mechanical Engineering, K L University, Guntur, India-522502 Assistant Professor, Department of Mechanical Engineering, K L University, Guntur, India-522502 Assistant Professor, Department of Mechanical Engineering, K L University, Guntur, India-522502 basam.koteswararao@gmail.com;+91-9394810064;9951045471 ABSTRACT The new capital area of andhrapradesh having huge power demand. We can meet up to certain requirement throughout the year by using renewable energy resources like solar energy. Because this is the place where the sun intensity available much more. Our paper gives better utilization methods of sun energy through these methods. Even though we are having plenty amount of solar energy availability but we are unable to utilize solar energy effectively due to temperature variation from time to t...

2022, Mechanics and Mechanical Engineering

The process of melting of a phase-change material (PCM) in eccentric horizontal cylinders geometry is studied numerically. Numerical simulations are performed for symmetric melting of phase change material between the two cylinders using the finite volume method. The inner cylinder is a finned-tube to enhance the heat transfer between the inner cylinder and the PCM. Inner cylindrical is considered as hot wall while outer is insulated. These simulations show the melting process from the beginning to the end. As result, it is found that the use of fins on the inner tube increases the melting process by decreasing the time of melting by 72.72 %.

2022, Thermal Science

Experimental research demonstrates the performance of electronic devices on plate fin heat sinks in order to guarantee that operating temperatures are kept as low as possible for reliability. Paraffin wax (PCM) is a substance that is used to store energy and the aluminum plate fin cavity base is chosen as a Thermal Conductivity Enhancer (TCEs). The effects of PCM material (Phase shift material), cavity form base (Rectangular, Triangular, Concave and Convex) with PCM, Reynolds number (Re= 4000-20000) on heat transfer effectiveness of plate fin heat sinks were experimentally explored in this research. The thermal performance of concave base plate fin heat sink with PCM is increased up to 7.8% compared to other cavity base heat sinks.

2022, Renewable and Sustainable Energy Reviews

Increasing energy demand calls for the implementation of proper thermal energy storage which is one of the most important components of solar energy conversion systems. Phase change material based latent heat energy storage systems have emerged as a promising option to effectively store thermal energy. Generally, paraffin wax is used as the most common phase change material for low to medium temperature storage applications because it has a large latent heat and low cost besides being stable, nontoxic and non-corrosive. The performance of paraffin wax based latent heat energy storage systems (LHESS) is limited by its poor thermal conductivity. In this paper, the previous experimental and theoretical research studies on LHESS using paraffin wax as phase change material with different performance enhancement techniques are reviewed. Further, research works related to dispersing different kind of nanoparticles in paraffin wax for the enhancement of its thermal conductivity are comprehensively reviewed with respect to synthesis, characterization and thermophysical properties of the nanoenhanced phase change material.

2022, Journal of Energy Storage

Mixture of MWCNT nanoparticles and paraffin with melting point of 24.5 • C has been utilized for saving the energy inside the ventilating system. The utilized duct for transportation of air has various tubes containing the paraffin and four styles for such obstacles have been presented. Finite volume method for modeling the melting procedure was utilized and validation test based on previous numerical article indicated good accommodation. Temperature of system at t = 0 is 6.5 • C less than 24.5 • C and hot laminar air flow with temperature of 14 K greater than initial temperature makes the paraffin to melt. With adding MWCNT nanoparticles the required time of charging reduce from 7.015 h to 6.74 h when DR = 0.16 which is associated with promising influence of such particles in augmentation of heat absorption. Moreover, as diameter of tube changes from 9.7 cm to 5 cm, the melting time declines from 6.74 h to 4.12 h. The needed time of process declines around 58.7 % with utilizing smaller tubes in existence of nanoparticles.

2022, Energy Conversion and Management

In summer, the temperature is very high inside vehicles parked under the hot sun. This causes consuming more fossil energy to power the air conditioner and generation of harmful gases. There is currently no effective method to address this problem in an energy-saving and environmentally friendly manner. In this paper, a novel solar-powered air-cooling system for vehicle cabins is proposed based on Phase-change Materials (PCMs); the system prevents the temperature inside a vehicle cabin from rising too high when the vehicle is parked outdoor exposure to the sun. The proposed system consists of three main parts: a solar-energy collection module, powerstorage module and phase-change cooling module. The solar panel converts solar energy into electricity, and the power-storage module stores the electric energy in a supercapacitor that provides power for the phase-change cooling module. Heat exchange between cabin ambient air and the PCMs is conducted in the cooling module to generate cold air. The proposed system is demonstrated through thermal simulations, which show the longduration cooling effect of the system. Temperature drops of 30°C were obtained in field tests, predicting that the proposed cooling system is beneficial and practical for cooling vehicle cabins.

2022, Energy Conversion and Management

2022, Annales de Chimie - Science des Matériaux

2022, Hittite Journal of Science & Engineering

E nergy storage is a significant solution for the later or cheap usage of energy, when the energy source is unavailable or expensive. The main problem related to renewable energy utilization is the time difference between the energy demand and the availability of energy sources. The most common method for solving this mismatch problem is energy storage. Thermal energy storage (TES) is a common and advanced one among the energy storage methods [1, 2]. Basically, TES is to store the energy in a storage medium by converting the energy sources to heat. TES is divided into two sections, which are sensible and latent TES. While sensible TES is to store the energy as heat by changing the temperature of the storage medium, latent TES is to store the energy as heat by changing the phase of storage medium. TES types and storage materials are selected according to the storage capacity, environmental condition, working condition, type of energy sources, etc. Sensible TES

2022

This paper presents a detailed review of the research carried out for the design of flat fin heat exchangers is using theoretical, experimental, and computational fluid dynamics (CFD) methods. The scope and limitations of several studies are presented, as well as the critical point of view of the authors in the selection of optimal methods in the thermo-hydraulic design of each equipment. Fin heat exchangers optimization is done using different approaches. The theoretical model assumes considerations that do not fully replicate the phenomenon, the experimental method provides real parameters for the design and implies high costs, and finally, computational fluid dynamics predicts the behaviors of thermal and hydraulic machine flows, in addition to recreating the phenomena almost exactly and complement the theoretical and experimental methods. With this review, it can be verified that the methods complement each other, thus achieving greater profitability at the industrial level, gre...

2022

Thermal energy storage (TES) modules are specifically designed to respond to transient thermal loading. Their dynamic response depends on the overall structure of the module, including module geometry and dimensions, the internal spatial distribution of phase change material (PCM) and conductive heat-spreading elements, and the thermophysical properties of the different materials composing the module. However, due to the complexity of analyzing a system’s dynamic thermal response to transient input signals, optimal design of a TES module for a particular application is challenging. Conventional design approaches are limited by (1) the computational cost associated with high fidelity simulation of heat transfer in nonlinear systems undergoing a phase transition and (2) the lack of model integration with robust optimization tools. To overcome these challenges, I derive reduced-order dynamic models of two different metal-PCM composite TES modules and validate them against a high fideli...

2021, SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019

Due to the mismatching between the renewable energy source and the energy demand, the energy storage devices have attracted the attention of the scientific community in order to maximize their performance. Several technologies have been developed and applied in laboratory scale and prototypes in the last decades. The energy storage devices can be mainly defined according to the average working temperature, the storage material, and the geometrical configuration. This work is focused on the 2D axisymmetric finite volume multiphase numerical simulations of the fluid flow and heat transfer within a shell-and-tube type latent heat thermal energy storage (LHTES). The effect of the geometrical parameters on the thermal performance of such systems is investigated. The influence of the LHTES shape is highlighted keeping constant the heat exchange area, the total storable heat and the heated surface temperature. Detailed description of the liquid fraction and temperature distribution during the solidification phase are reported. The solidification phase appears strongly influenced by the geometry. The geometries have been chosen according to fixed volume and heat exchange area condition. The ratio between the external and the internal radius (r e /r i) has been changed and its effect on the thermal performance of the thermal storage device is considered. Thus, according to the application requirement, particular care should be taken in the design of the shape of the LHTES device.

2021, Sustainability

This study aims to assess the effect of adding twisted fins in a triple-tube heat exchanger used for latent heat storage compared with using straight fins and no fins. In the proposed heat exchanger, phase change material (PCM) is placed between the middle annulus while hot water is passed in the inner tube and outer annulus in a counter-current direction, as a superior method to melt the PCM and store the thermal energy. The behavior of the system was assessed regarding the liquid fraction and temperature distributions as well as charging time and energy storage rate. The results indicate the advantages of adding twisted fins compared with those of using straight fins. The effect of several twisted fins was also studied to discover its effectiveness on the melting rate. The results demonstrate that deployment of four twisted fins reduced the melting time by 18% compared with using the same number of straight fins, and 25% compared with the no-fins case considering a similar PCM mas...

2021, Applied Sciences

There is a growing interest in sustainable energy sources for energy demand growth of power industries. To align the demand and the consumption of electrical energy, thermal energy storage appears as an efficient method. In the summer days, by using a cold storage system like ice storage, peaks of the energy usage shift to low-load hours of midnights. Here, we investigate the charging process (namely solidification) numerically in an ice-on-coil thermal energy storage configuration, where ice is formed around the coil or tube to store the chilled energy. The considered ice storage system is a shell and tube configuration, with three kinds of tubes including a U-shaped tube, a coil tube with an inner return line, and a coil tube with an outer return line. Advanced 3D unsteady simulations are achieved to determine the effects of tube type and position of the ice storage (horizontal or vertical) on the solidification process. Results indicate that using a coil tube speeds up the ice fo...

2021, SN Applied Sciences

Nowadays electrical power is one of the most vital requirements for daily life and industries. Since with the rise of the human population, providing electrical energy is an important challenge, some methods should be used to reduce the electrical demand or shift the demand from peak-hours to off-peak hours. Ice storage systems are one of the devices which can be used for this purpose. In this article, a transient 3D numerical simulation was carried out to investigate the effects of two geometrical parameters of double helical coil heat exchanger in the charging process of an ice storage system with the volume of 15 L. These parameters were helical coil pitch length and the distance between inner and outer coils. The results indicated that with higher values for pitch length and inner and outer coils distance, compared to smallest values for these parameters, the distribution of formed ice in the storage improves and the rate of ice formation increases by 22.81% and 13.99%, respectively. Increasing these values can also retard the ice block formation which is an undesirable phenomenon in the external discharge process of the ice storage systems.

2021, IAEME PUBLICATION

Energy is one of the key factors for development of the country, and it can be gained from dif erent sources, but some of these sources are not environmental friendly, expensive and dif icult to transport; like fossil fuel. Using solar energy is the best option to solve these problems. Ethiopia has huge potential for solar energy because it is located close to the equator. Refrigerator is one of the essential tools used in daily. Especially refrigerator is very required for the people who live in desert area for cooling water. The people living in grid connected system use electric powered refrigerator for cooling water, but people living in desert of -grid area can't get electric powered refrigerator. Therefore this problem would be solved when they use solar powered refrigerator. In this work Dire Dawa Shinile is study area of this paper. It is located at 9.68latitude and 41.85 Longitude. One of the major drawbacks of solar refrigerator technology has been the large battery systems that were required to store the sun’s energy for use during the night and cloudy periods. These batteries have a relatively short life time and replacements are expensive. In this work solar power refrigerator optimization is eliminates the expensive energy storage batteries and PV sizing for solar powered refrigerator depending on power requirement of compressor by using PVsyst software. Freeze water to make ice in ice storage tank by using the sun's energy which operate compressor of refrigerator and then by using these ice storage to cooling water drink, during solar energy couldn't drive compressor. The net capacity of the refrigerator use for cooling water is 33L and an ice storage of 1kg, is able to maintain 6 liter of water drink temperature below 5 as comfortable for drink. The initial cost of solar powered refrigerator is 13,266birr and this cost would be obtained back after one year. Solar powered refrigerator system can be reliably used at where the local grid is not continuously available whereas refrigeration need is critical.

2021

A twisted-fin array as an innovative structure for intensifying the charging response of a phase-change material (PCM) within a shell-and-tube storage system is introduced in this work. A three-dimensional model describing the thermal management with charging phase change process in PCM was developed and numerically analyzed by the enthalpy-porosity method using commercial CFD software. Efficacy of the proposed structure of fins for performing better heat communication between the active heating surface and the adjacent layers of PCM was verified via comparing with conventional longitudinal fins within the same design limitations of fin material and volume usage. Optimization of the fin geometric parameters including the pitch, number, thickness, and the height of the twisted fins for superior performance of the proposed fin structure, was also introduced via the Taguchi method. The results show that a faster charging rate, higher storage rate, and better uniformity in temperature distribution could be achieved in the PCMs with Twisted fins. Based on the design of twisted fins, it was found that the energy charging time could be reduced by up to 42%, and the energy storage rate could be enhanced up to 63% compared to the reference case of straight longitudinal fins within the same PCM mass limitations.

2021

• Nanoparticles in multi-PCMs with cascaded foam for energy storage were studied. • Solidification of the PCM was modeled and validated via previous experiments. • Role of nanoparticles with cascaded foam for improved solidification was... more

2021, SN Applied Sciences

The use of numerical simulation approach to investigate the effect of transient boundary temperature on an LPG tank structure was investigated. Here, both transient thermal and structural system were coupled in ANSYS software version 19.2 to create an interaction between the thermal and mechanical load on the tank structure. The focus of this paper is to identify stress hotspot which may eventually lead to stress-corrosion using a non-linear solver. Literature has proven that temperature gradient acting on a material is a possible cause for failure in most engineering structures due to stress induced corrosion. In this study the effect of a time dependent change in the temperature of the material (304 stainless steel) was investigated. The temperature was set to increase from cryogenic to 30 °C, and the pressure which represents mechanical load was also implemented at the wall boundary. Results obtained showed that stress was concentrated at the principal plane connecting the tank roof to the cylindrical structure. However, a failure analysis was conducted were the mechanical load was increased to 3 × 10 43 Pa. It was found that the material failed after 1,000,000 s time steps and the tensile yield strength obtained from the stress-strain curve was lower than the material standard value. This can be explained with the concept that the action of temperature disrupted the material microstructure, hence, reduced the material stiffness to fracture. The stress-strain curve was validated with the standard plot for the 304 stainless steel material type.

2020, SN Applied Sciences

2020, Appl. Sci. 2020

2020, SN Applied Sciences

Energy consumption is rising around the world and most of the activities in the developed countries are dependent on electric energy. Thermal energy storages are one the ways to reduce energy consumption and balance the electrical power usage during the day. With thermal energy storages, or to be precise, with ice storage systems, energy usage peak can the shifted from the afternoon or early night to low-load hours of morning or midnights. In this study, a 3D unsteady numerical analysis was done in order to examine an ice storage system equipped with serpentine tube heat exchanger. The influence of two geometrical parameters, namely, tube diameter and serpentine tube row distance were investigated. The examined range for diameter and the serpentine tube row spacing were 15-21 and 30-100 mm, respectively. The results showed that placing the serpentine tube rows more distant to each other increases the ice formation so that the ice formation rate for the highest serpentine tube row distance compared to when the serpentine tube row distance is the lowest is higher by 24.68%. On the contrary, with a larger tube diameter, the rate of ice formation was decreased so that the smallest diameter had almost 5.9% more ice formation rate in comparison with the case with the largest tube diameter.