PERFORMANCE ANALYSIS OF LATENT THERMAL ENERGY SYSTEMS DURING MELTING AND SOLIDIFICATION WITH PCM: A REVIEW
Shekh Irfan Kadari, Vishwajeet Kureel
Abstract - Latent thermal energy storage could be a way for storing energy for later use in different application. This can be utilized in many applications like insulated buildings, natural phenomenon and house shuttles. The major problem in such systems is comparatively low charging and discharging power i.e. the time to complete melting and solidification either in low thermal physical philosophy or in giant attributable. By using phase change materials like RT-35 many ways to raise the performance of the system are examined. Present work is dealing with the evolution of latent thermal energy storage in exceedingly coaxal element through each melting and solidification using PCMs RT35. It is a comparative study of simplified 2-D model of horizontally and vertically oriented shell and tube device for RT-35 PCMs. Ansys Fluent 18.1 is used as a Platform for CFD Programme through 4 different models. The results show that the vertical orientation performs higher in all cases, melting and solidification for RT-35.
1 BASIC PRINCIPLE
The basic principle that the energy is supplied to a storage system for removal and uses this at a later time.
Basically the method of storage and scale of storage varies in different systems. In TES System involving three steps charge, storage and discharge, giving a complete cycle.
Figure 1 TES storage cycle
TES system may be smart, latent and chemical storage. The differences between these strategies are area and fabric, temperature and some alternative parameters. Another factor is important regarding TES is that the length of your time the energy i.e. warmth and cold is hold on, TES can also be classified as short or future (seasonal storage). A buffer tank is used to scale back the power of warmth generator in system, so thermal demand conferred normally throughout the mornings or evenings within the thermal systems, that reduces the thermal power of gas boilers or CHP plants. To tackle seasonal temperature
variations, heat is collected throughout the nice and cozy summer, as an example in massive water ponds (e.g. 60,000 m3), exploitation Solar thermal collectors. It will then be hold on and later discharged to dwellings within the winter. Conversely, a chilly store is charged in winter and so offer cooling throughout summer.
1.1 Types of Thermal Energy Storage
1
Sensible heat storage2
Latent heat storage system3
Thermo-chemical heat storage 1.2 Types of phase change material Organic PCMsHydrocarbons, primarily paraffins (CnH2n+2) and lipids but also sugar alcohols
Advantages
Freeze without much super-cooling
Ability to melt congruently
Self nucleating properties
Compatibility with conventional material of construction
No segregation
Chemically stable
Safe and non-reactive Disadvantages
Low thermal conductivity in their solid phase. High heat transfer rates are required during the refrigeration cycle. Nano composites were found to yield an effective thermal conductivity increase up to 216%
Volumetric latent heat storage capacity can be low
Flammable. This can be partially alleviated by specialised containment.
2 LITERATE REVIEW
Kannan, J. Prakash, D. Roan et.al.
2021 developed An off-grid star combisystem with integral heat of transformation storage unit is intended for active house and water heating throughout day and passive house heating throughout night.
The star combi-system performance shows that the typical energy saving quantitative relation and energy saving obtained for house heating were ~ ninety three and ~ a pair of.8 kWh, severally. it had been discovered that the air temperature within the state change material integrated house unit (area coverage
~60%; melting point: twenty three
°C) stay ~ four to six °C cooler than corresponding while not state change material integrated house unit. The semi-permanent performance analysis of the solar combi-system shows that the off- grid system will with efficiency maintain the house temperature in a very comfortable zone throughout winter and summer season together with water heating for residential application. . it's evident that the off-grid state change materials integrated star comb-isystem will result in vital energy saving in residential buildings each in colder and hotter climatic conditions.
Zhi Li ,Yiji Lu, Rui Huang et al 2021 considered Thermal energy storage (TES) technology to Balance the demand and supply and overcoming the intermittency and fluctuation nature of real- world heat sources, making a more flexible, highly efficient and reliable thermal energy systems. This review aims to recognize potential methods to design and optimize LTES heat exchangers for heat recovery and storage, bridging the knowledge gap between the present studies and future technological developments.
The key focuses of this work can be
described as follows:
1. Insight into moderate-high temperature phase change materials and thermal conductivity improvement methods.
2. Various configurations of latent thermal energy storage heat exchangers and relevant heat transfer enhancement techniques 3. Applications of latent thermal
energy storage heat exchangers with different thermal sources, including solar energy, industrial waste heat and engine waste heat, are discussed in detail.
Ahmed H.N. Al-Mudhafar et al 2020 to make-out improvement in thermal performance of PCM thermal energy storage system a modified webbed tube heat exchanger was introduced and numerical investigation is made.
The performance of this heat exchanger is compared with webbed tube heat exchanger and the triple tube heat exchanger. 2- D numerical models were developed which enabled us to simulate conduction and natural convection heat transfer mechanisms. And the whole process of solidification was monitored. It concluded that the PCM solidification process accelerates by 41% when applying the modified webbed tube heat exchanger compared to the webbed tube heat exchanger.
Hussam Jouhara et al 2020 presented different methods of thermal energy storage including sensible heat storage, latent heat storage and thermo chemical energy storage, focusing mainly on phase change materials (PCMs) as a form of suitable solution for energy utilization to fill the gap between demand and supply to improve the energy efficiency of a system. . The article presents a classification of PCMs according to their chemical nature as organic, inorganic and eutectic and by the phase transition with their advantages and disadvantages. In addition, different methods of improving the effectiveness of the PCM materials such as employing cascaded latent heat thermal energy storage system, encapsulation of PCMs and shape-
stabilization are presented in the paper. Furthermore, the use of PCM materials in buildings, power generation, food industry and automotive applications are presented and the modeling tools for analyzing the functionality of PCMs materials are compared and classified.
Nan Zhang Yanping Yuan et al 2020 synthesized a series of nano- encapsulated phase change materials (Nano-PCMs) with paraffin wax (PW) as core and melamine-formaldehyde (MF) as shell by the in-situ polymerization method. The morphology chemical structure and thermal properties of prepared Nano- PCMs were characterized by scanning electron microscope, Fourier transform infrared, differential scanning calorimetry and thermo-gravy metric analyzer. The results show that the PW is successfully encapsulated in the MF without chemical interaction, and the Nano PCMs present regular spherical shape with the average diameter of 260–450 nm. The encapsulation efficiency of the Nano PCMs increases with the augment of the supplied amount of core material.
The maximum encapsulation efficiency of the Nano PCMs can reach up to approximately 75%. The Nano PCMs can maintain excellent thermal reliability and stability after 2000 thermal cycling. The prepared Nano PCMs can be well applied in the latent heat thermal energy storage and thermal management systems due to their remarkable encapsulation efficiency and thermal properties.
Manoj Kumar Soni, Nisha Tamar &
Suvanjan bhattacharya et al 2020 established numerical analysis of the transient performance of the heat of transformation thermal energy storage unit on finite distinction methodology. the warmth exchange between the HTF, wall and PCM has been investigated by developing a 2- D absolutely implicit numerical model for the storage module and resolution the whole module as a conjugate downside exploitation physical property reworking
methodology. A comparative investigation of the whole melting time of the PCM has been performed supported natural convection in liquid PCM throughout the charging method. The novelty of this paper lies within the reality it includes convection in PCM and this investigation includes an in depth constant study which might be used as a relevance style heat of transformation storage. The results indicate that natural convection accelerates the melting method by a major quantity of your time. so as to optimize the look of the thermal storage unit, constant study has been attended to research the influence of assorted HTF operating conditions and geometric.
Bruno Cárdenas Noel León et al 2018 a series of state change materials, principally inorganic salt compositions and metal like alloys, that might doubtless be used as storage media in an exceedingly warmth (above three hundred °C) heat storage system, seeking to serve the reader as a comprehensive thermo- physical properties info to facilitate the fabric choice task for prime temperature applications
Widespread utilization of heat energy storage systems has been control back by the poor thermal conduction and a few alternative inherent drawbacks of the employment of PCMs; this paper reviews many heat transfer and performance sweetening techniques projected within the literature and discusses variety of style issues that has got to be taken under consideration attending to offer a broad summary for the planning of hot temperature heat energy based mostly thermal energy storage systems.
Jaykumar H. Patel M. N. Qureshi P.
H. Darji et al 2018 assessed the performance of air primarily based PCM storage system for cooling and heating of building. The execution of the targeting state change material storage system was noted most once temperature of state change material was twenty two.5°C in winter season and twenty eight.8°C(∼29°C)
throughout summer amount.
Summer, whereas 26.8°C was found throughout remaining a part of the year. once the temperature goes below twenty six.8°C, cooling capability of system is additional as compare to heating capability. Study conjointly concludes that the result of temperature of PCM includes a nice result on cooling in summer amount and its storage are often utilized in winter season.
Samer Kahwaji Michel B jonshon et al 2018 The PCMs investigated include three pure alkanes, nonadecane, eicosane, docosane, and three commercial blends of paraffin waxes.
For each PCM, we accurately determined Tmpt, the latent heat of fusion, the density of the solid phase and the temperature dependences of the heat capacity and thermal conductivity. For the first time, we show the thermal stability of the PCMs after 3000 melt-freeze cycles, and their chemical compatibilities with 17 different metallic and plastic materials used for encapsulation and in composites and fillers. These results provide necessary information to improve energy modeling and analysis for existing and emerging TES applications, and guide the selection of reliable paraffin PCMs and encapsulation materials for such applications.
B BecattiniL. Geissbühler G.
Zanganeh A Haselbacher A. Steinfeld et al 2018 showed that the latent thermal-energy storage reduced the drop in the air outflow temperature during discharging. Minor leaks of the phase-change material were traced to the welding seams in the encapsulation as well as to holes required to insert resistance temperature detectors. Analysis of the leaked phase-change material revealed degradation and/or phase separation, which were attributed to the initial off-eutectic composition of and impurities in the phase-change material and resulted in a reduced heat of fusion. Simulations predicted the performance of the combined thermal-energy storage with good overall accuracy. Discrepancies were put down to changes in the thermo
physical properties
Kunal bhagat, Sandip K. Saha et al 2016 presented a numerical study on the transient response of packed bed heat energy thermal energy storage system in removing fluctuations within the heat transfer fluid (HTF) temperature throughout the charging and discharging amount. A comprehensive numerical model is developed victimization flow equations for HTF and two- temperature non- equilibrium energy equation for warmth transfer, including H methodology to account for physical change in PCM. it's found that the power of the heat energy thermal energy storage system to store and unleash energy is considerably improved by increasing mass rate and body of water charging temperature. The transient variation within the HTF temperature may be effectively reduced by decreasing consistence dimensions on the whole melting time of the PCM.
Hua Zhang Xuenong Gao et al 2016 In this work, a rapid charging tube- in-tank LTES system is developed by applying a compact spiral coil tube and paraffin/expanded graphite composite PCM with a high thermal conductivity simultaneously.
Numerical simulation coupling heat transfer at the solid-liquid interface is used to investigate the thermal energy storage performance of the LTES system and the results show a good agreement with the experimental data. It is found that heat transfer temperature difference has a great influence on performance of the LTES system, while Reynolds number ha s a relatively little effect especially when Reynolds number is higher than 8700. Besides, the optimal ratio of the helix radius of the spiral coil tube to the radius of the PCM tank is confirmed to be between 0.53 and 0.64. Moreover, increasing bulk density of the composite PCM can bring about a shorter thermal energy storage time.
In summary, the results are valuable for the design of a similar LTES system.
Karthik Nithyanandam, Ranga Pitchumani et al 2013 numerically investigated the sweetening within the thermal performance of charging and discharging method of LTES system by embedding thermo- syphons. A transient, procedure analysis of the LTES system with embedded thermo-syphons is performed for each charging and discharging cycles. The influence of the planning configuration of the system and also the arrangement of the thermo-syphons on the charge and discharge performance of the LTES put in during a concentrating alternative energy plant (CSP) is analyzed to spot configurations that result in improved effectiveness.
R. Meenakshi Reddy et al 2012 within the gift experimental work, thermal energy storage system (TESS) is intended, made-up and commissioned to gather thermal performance information on the thermal energy tank. This TES tank has spherical capsules, embedded with natural action material as wax and octadecanoic acid. the warmth transfer fluid(HTF) is employed as water. the current work aims to research the charging (melting of PCM) and discharging (solidification of PCM) characteristics of natural action material in TES tank
3 CONCLUSION
Two different orientations of a shell and tube heat exchanger were compared and their performance studied during melting and solidification. The results from the numerical Analysis show that:
The melting time for the horizontal orientation is approximately 33,000 seconds and the melting time for the vertical orientation is about 11,000 seconds.
The solidification time for the horizontal orientation is approximately 55,000 seconds and the solidification time for the vertical orientation is about 29,000 seconds.
A vertical orientation of the heat exchanger induce a melting time about 200% faster than the horizontal orientation.
A vertical orientation of the heat
exchanger induce a solidification time about 90% faster than the horizontal orientation.
The main reason for the difference of performance in time is the effect of gravity upon the heat exchanger, which induce a larger portion of natural convection.
LTES:s should be designed to maximise natural convection as the main heat transfer mechanism.
The models considered in this thesis are both unrealistic to use in practice, due to the long charging and discharging time. More efficient geometries should be explored.
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