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Latent heat storage modules for preheating internal combustion engines: Application to a bus petrol engine
Abstract
The heat storage (HS) system for pre-heating a bus petrol engine before its ignition was mathematically modelled and experimentally investigated. The development of such devices is an extremely urgent problem especially for regions with a cold climate. HS system working on the effect of absorption and rejection of heat during the solid-liquid phase change of HS material is realised, tested and results of R&D are discussed. Numerical modelling was performed to calculate the HS mass-dimensional parameters. In the experimental part of the paper results of experiments on the pre-heating device to start a carburettor engine and analysis of data received are given. There is a good correlation between the experimental data and the results of numerical modelling of HS system functioning.
... Vasiliev et al. [113][114][115] carried out mathematical modeling and experimental research to evaluate the pre-heating influence of heat storage (HS) system in a gasoline engine. The HS system mainly consists of cylindrical envelope containing capsules of PCM inside. ...
... Schematic diagram of the engine cooling system with HS[115].A.A.M. Omara ...
... The PCM could improve the exergy efficiency of E&PR by 366.6%. Vasiliev et al.[113][114][115] •The HS system increased the average engine temperature from − 10 to 23 • C in only 500 s. With 4 kg load, the incorporation of pure PE showed 38.33% and 14.31% charging efficiency and energy saving, respectively. ...
Since most of the energy consumed by an internal combustion engine (ICE) is wasted, heat recovery from the exhaust and coolant is considered as a promising technology for improving the engine efficiency. The systems that used for recovering wasted thermal energy are called waste heat recovery (WHR) systems. However, most WHR methods suffer from main drawbacks such as difficult implementation, low thermal controllability and poor thermal storability. These drawbacks could be overcome by integrating thermal energy storage (TES) systems with ICEs. TES relies on sensible heat, latent heat and thermochemical storage. Latent heat storage method with phase change materials (PCMs) is the most utilized in ICEs because of its good controllability and high storage capacity. Therefore, this review presents the applications of TES with PCMs for recovering waste energy in ICEs. The literature shows that PCMs could be incorporated into different ICEs systems including exhaust recovery systems, cooling recovery systems, catalytic converters, diesel generators, evaporator and pressure regulators, additional diesel heaters, and cylinder's body. The previous studies on these systems show the potential of TES with PCMs in storing and recovering waste heat. Moreover, it is shown that the recovered heat by PCMs is mainly used for purposes of engine pre-heating during cold-start, maintaining hot temperature of catalysts for better conversion efficiency, and heating domestic and industrial water. Finally, the problems of PCMs with ICEs such as bulky system problem, high initial cost, corrosion issues, and poor stability; are also discussed in this review.
... The CA-LA-PA mixture was placed at 60°C until completely melted, then 12 h was required for electro-spun SiO 2 nanofibers immersed into the molten CA-LA-PA mixture, finally the composite was hung in the oven at 60 ℃ for 10 h. Morphological images of the composites are shown in Fig. 3. Experiments found that SiO 2 nanofibers were capable of [128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144][145] absorbing plenty of CA-LA-PA mixture, the maximum absorption capacity was close to 81.3 wt% (weight percent). The composite PCM possessed high thermal reliability with results showing little variations in phase transition temperatures after 50 thermal cycles. ...
... Some fillers with certain structure and property were added to form thermally enhanced composites. Carbon fiber/graphene nanoplatelets [48], single-walled carbon, nanotubes/graphite nanoplatelets [49], multiwalled carbon nanotube/graphene [50] and boron nitride/multi- Renewable and Sustainable Energy Reviews 72 (2017) [128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144][145] walled carbon nanotube [51,52] have been fabricated. Carbon fiber is compatible with the majority of the PCM ascribing to its noncorrosiveness and low density. ...
... Renewable and Sustainable Energy Reviews 72 (2017) [128][129][130][131][132][133][134][135][136][137][138][139][140][141][142][143][144][145] more sensitive to temperature change, and the effective thermal conductivity was as much as three times higher than that of the first type. Both methods performed thermal conductivity enhancement. ...
Phase change material (PCM), stores and releases heat at a particular required temperature as it undergoes phase change at that temperature. Because of their large latent heat and constant temperature during the phase change process, the PCMs are extensively used in latent thermal energy storage system (LTES) and thermal management system (TM). Due to its virtue of competitive performance, PCM has been used extensively in heat recovery, solar energy, aerospace industry, buildings, textile industry etc. However, the PCM has limitations like low thermal conductivity and low heat transfer rate, which decrease the performance of LTES and TM systems. In this work, ways of improving thermal conductivity and heat transfer rate of the composite PCMs (CPCMs) are summarized from perspective of three kinds of CPCMs’ morphologies (fiber, porosity and sphere). This review paper presents morphological characterization of the CPCMs, and several fabrication methods of the CPCMs with enhanced thermal properties.
... Ismail et al. [171] presented studies about ice storage in bank geometry with finned tubes, studying the influence of parameters like inlet fluid temperature, initial temperature of PCM, and thermal conductivity of the tube, in the solidification front. Thermal storage of solar energy [3,12,25,32,46,88,140,141,204,205,[224][225][226][227][228][229] Passive storage in bioclimatic building/architecture (HDPE þ paraffin) [9,34,89,91,92,181,[188][189][190][191][192][193][194][200][201][202][203] Cooling: use of off-peak rates and reduction of installed power, icebank [29,171,181,[195][196][197][198][199][210][211][212][213][214][215][216][217]219] Heating and sanitary hot water: using off-peak rate and adapting unloading curves [54,87,120,142,[206][207][208][209] Safety: temperature maintenance in rooms with computers or electrical appliances [220] Thermal protection of food: transport, hotel trade, ice-cream, etc. [54,56,173,181,218] Food agroindustry, wine, milk products (absorbing peaks in demand), greenhouses [189,[221][222][223] Thermal protection of electronic devices (integrated in the appliance) [54,172,173,178] Medical applications: transport of blood, operating tables, hot-cold therapies [54,172] Cooling of engines (electric and combustion) [178][179][180][182][183][184][185][186][187] Thermal comfort in vehicles [230] Softening of exothermic temperature peaks in chemical reactions [189] Spacecraft thermal systems [96] Solar power plants [232][233][234][235][236][237] ...
... When the engine is stopped, the heat is stored and can be used to preheat the engine on a new start. Using the heat store it is possible to reach an optimised working temperature within the engine in a much shorter time than without heat store [187]. ...
... These types of materials have many useful properties including heat source at constant temperature, heat recovery with small temperature drop, high storage density, melting point which matches the applications, low vapor pressure (1 bar) at the operational temperature, and chemical stability and non-corrosiveness. These properties allow the PCM to be used in many industrial applications such as thermal storage of solar energy [1e6], thermal management of electronic devices [5e7], thermal storage in buildings [8,9], cooling of engines [10,11]. ...
... It is obvious that Eqs. of (10) and (11) are employed in liquid region of NEPCM while other relations are applied in all region of NEPCM. The Rayleigh and Prandtl numbers for the NEPCM are given in the following equations: ...
This paper presents a numerical study of unconstrained melting of nano-enhanced phase change materials (NEPCM) inside a spherical container using RT27 and copper particles as base material and nano-particle, respectively. Numerical studies are performed for three different Stefan number and volume fraction of nano-particles with an initial sub-cooling of 6 °C. Transient numerical simulations are performed for axi-symmetric melting inside a sphere. The simulation results show that the nano-particles cause an increase in thermal conductivity of NEPCM compared to conventional PCM. The enhancement in thermal conductivity with a decrease in latent heat results in higher melting rate of NEPCM.
... Today, due to the environmental pollution and the non-renewability of fossil fuels, the need to use new methods to prepare clean and renewable fuels such as thermal energy is felt more [4]. One of the most important methods of the thermal energy storage is the use of phase change materials or PCM, which can be used in oil tanks to reduce the energy consumption to a great extent when necessary [5]. It changes phase and stores energy in different forms and releases this stored energy when needed, hence these materials are important especially in the oil industry. ...
Current research has simulated polymer oxide/metal oxide nanofibers (nanocomposites) through the COMSOL Multiphysics software. The oil was placed inside a cylindrical tank covered with a thin layer of phase change material nanocomposites. A combination of polyethylene glycol (PEG) as a the phase change material (PCM) and polyamide 6 (PA6) as a support matrix for nanofibers were used. The effect of some parameters such as the type of metal oxide nanoparticles (Al2O3, Fe2O3, TiO2, and CuO), the ratio of metal oxide to polymer (2% and 8% by weight), and time (600 and 4800 s) on some thermophysical properties such as changes in temperature, density and thermal conductivity were investigated. The simulation results showed that the most suitable system for thermal management is related to the presence of nanoparticles and PCM with the highest weight percentage. It was also found that the use of the nanofibers of phase change materials is very effective in improving thermal management and temperature control. As a result, they can be used as suitable materials for storing and transferring energy. The addition of 8% nanoparticles led to a 22.5% increase in thermal conductivity. Also, by providing the same initial and boundary conditions for all cases, the amount of melting in the presence of nanoparticles with a high percentage (8%) was higher than the with a low percentage (2%). As a result, the addition of nanoparticles to increase the melting rate can be very useful for various heat management purposes such as energy storage.
... Moreover, the literature contains experimental research and computer modelling of heat storage devices for preheating gasoline engines operating in real winter conditions [14]. Cold-start emissions from internal combustion engines were reduced using catalyst converters integrated into PCMs [15]. ...
The significance of diesel engines in practical applications is unquestionable, yet the challenge of emission control remains paramount. Engine emissions comprise nitrogen oxides (NOx), sulfur oxides (SOx), carbon monoxide (CO), particulate matter, and greenhouse gases. Nitrogen oxides, contributing to increased tropospheric ozone and hydroxyl radical concentrations, are implicated in photochemical smog formation. Sulfur oxides contribute to sulfuric acid production, posing risks to human respiratory health. Carbon monoxide, with its capacity to inhibit oxygen transportation in the bloodstream, presents lethal implications. This study primarily targets the reduction of nitrogen oxide emissions, employing phase change materials (PCMs) in an innovative emission mitigation approach. The research methodology entails a comprehensive literature review, computational fluid dynamic modeling, and simulation experiments. The environmental impact of diesel combustion is meticulously evaluated, with an emphasis on the role of phase change materials in emission reduction. The investigation encompasses a holistic analysis of diesel combustion, including a numerical modeling and simulation of phase change materials, comprehensive combustion analysis via system software, and a comparative study of combustion outcomes with and without PCM intervention. The efficacy of the approach is evaluated against engine performance and the consequent decrease in emission percentages. Remarkably, the application of paraffin wax at the exhaust port of the cylinder head resulted in a 45% reduction in nitrogen oxide emissions. This research, thereby, provides invaluable insights for further experimental efforts aimed at minimizing thermal nitrogen oxides through minor engine block modifications. Consequently, this study serves as a significant step towards environmentally responsible diesel engine utilization.
... The TES system mainly used sodium sulfate decahydrate as the PCM, it can increase the engine temperature by 17.4 °C before cold start, the maximum thermal efficiency of the TES system can reach 57.5%, reducing CO and CH compound emissions by 64% and 15%, respectively. In short, PCMs have been studied and applied in automobiles, such as engine preheating [220,270], improving thermal comfort of automobiles [32], and three-way catalyst preheating [41,42]. ...
In order to achieve global carbon neutrality in the middle of the 21st century, efficient utilization of fossil fuels is highly desired in diverse energy utilization sectors such as industry, transportation, building as well as life science. In the energy utilization infrastructure, about 75% of the fossil fuel consumption is used to provide and maintain heat, leading to more than 60% waste heat of the input energy discharging to the environment. Types of low-grade waste heat recovery technologies are developed to increase the energy efficiency. However, due to the spatial and temporal mismatch between the need and supply of the thermal energy, much of the waste thermal energy is difficult to be recovered. Thermal energy storage (TES) technologies in the forms of sensible, latent and thermochemical heat storage are developed for relieving the mismatched energy supply and demand. Diverse TES systems are developed in recent years with the superior features of large density, long-term, durable and low-cost. These technologies are vital in efficient utilization of low-grade waste heat and expected for building a low or zero carbon emission society. This paper reviews the thermal storage technologies for low carbon power generation, low carbon transportation, low carbon building as well as low carbon life science, in addition, carbon capture, utilization, and storage are also considered for carbon emission reduction. The conclusion and perspective are raised after discussing the specific technologies. This study is expected to provide a reference for the TES technologies in achieving zero-carbon future.
... Due to the aforementioned characteristics, LTES have been traditionally researched in areas such space exploration, solar energy, HVAC-R, buildings, and electronic cooling. Nevertheless, different applications were also reported, as in vaccine and food carriers (Devrani et al., 2021;Hoang et al., 2015), firefighter vests (Hu et al., 2013), internal combustion engines (Vasiliev et al., 2000), and cancer therapy (Cao et al., 2021). Both experimental and theoretical approaches are widely adopted. ...
Latent thermal energy storage, employing phase-change materials, has been traditionally researched in several areas such solar energy, refrigeration, and electronic cooling, but less conventional applications, e.g. cancer therapy, are also emerging. In this review, theoretical studies categorized in a wide range of subjects are critically discussed. Some topics commonly found in the literature are analyzed, including (not limited to) intensification techniques of heat transfer and numerical methods. Nevertheless, less reported matters are also discussed, such the development of correlations and the utilization of non-conventional techniques to enhance heat transfer. Besides, this work is arranged in a timeline, so that the origins of each topic are tracked and followed along the years to better identify the incremental and disruptive contributions. As an example, first attempts to compare different algorithms to solve phase-change problems, were identified in the 1990′s. To cite more significant advancements, the 2000′s was marked by the first use of artificial neural networks and by the birth of nano-enhanced phase-change materials. Lastly, research gaps and prominent research fields are pointed out as the consequence of mapping the state of the art. A sample of identified gaps are the: (i) investigation on the Newtonian behavior of nano-enhanced phase-change materials in the liquid state, (ii) better investigation on the porosity constant values, for the same phase-change material under different conditions. On the other hand, some promising fields revealed were the development of correlations to predict several parameters and the investigation of non-conventional techniques, e.g. magnetic fields and ultrasound. Latent thermal energy storage was found to possess some well understood behaviors for a ready implementation in commercial scales, but also presents a wide range of areas for continuous research and development.
... Recent years have seen a widespread application around the world of thermal energy storage by using the latent heat of working fluid phase transition. This method is used in generating power by means of renewable energy sources [6][7][8], in motor vehicle construc-tion [9,10], and in the construction of buildings [11]. An interest in this thermal energy storage field is also maintained as applied to nuclear energy [12,13]. ...
Growth in the number of nuclear reactors in power systems and their involvement in controlling the electricity consumption schedule call for the need to impose more stringent requirements for their safety. It is shown that the safety of NPPs can be enhanced, and their participation in variable power-consumption schedules can be implemented by combining them with latent heat thermal energy storages (LHTES) and an additional small-capacity steam turbine. A scheme is proposed for combining a two-loop nuclear power plant with a multifunctional thermal energy storage system (TESS) on the basis of an LHTES, with means for heating feedwater above the nominal temperature in the LHTES discharging period. With such a solution, it becomes possible to increase the live steam flowrate without changing the reactor plant output power. The proposed scheme features high thermodynamic efficiency. In addition, doing away with the steam generation system in the LHTES results in that its design becomes significantly simpler and cheaper. Thus, due to increasing the feedwater temperature in a power unit with a VVER-1000 reactor from 215 to 260°С, the additional turbine can produce up to 140 MW of electric power. A distinguishing feature of the proposed scheme is that it allows uninterrupted power supply for the NPP auxiliaries to be provided in an emergency involving loss of power supply by using the steam generated due to the decay heat produced by the shutdown reactor. This makes it possible to enhance the NPP safety level in compliance with the growing requirements set forth by the International Atomic Energy Agency (IAEA) and ensure the possibility of power unit participation in controlling the electric load schedule without changing the reactor plant’s power output. Assessments of accrued net present value (ANPV) carried out with taking into account the multifunctional properties of the system being developed have shown that it has a positive value in the entire adopted range of the difference between the day and night electricity tariffs.
... Vasiliev et al. solved the problem with the use of PCM. The numerical and experimental study shows that preheating of an engine can be possible using latent heat thermal energy storage (LHTES) unit [37]. The experimental validation is done by running a bus with a heat storage unit in the winter season. ...
The use of phase change materials (PCMs) has enormous potential to store thermal energy from a low-temperature heat source as well as from waste heat as latent heat. The amount of latent heat in PCM is much higher than sensible heat. Therefore, this significant latent heat supply can partially fulfil the energy demand for certain applications. PCMs can supply energy during the power crisis. PCMs are also helping to meet the basic need of life during natural calamities. The enhancement of the thermal properties of PCM can improve the use of PCM as a sustainable resource. In this study, the different processes of thermal property enhancement according to the application are reported and presented in a compiled form. The study reflects that using additives and encapsulation, a change in thermal conductivity, phase change temperature, and latent heat of solid-liquid phase change can be achieved. The changes in size and shape of the PCM container cavity are also reported. There is an improvement in thermal energy storage capacity with an increase in the heat transfer area of the cavity. The review reveals that the encapsulated PCM and PCM composite can give a better performance in latent heat thermal energy storage compared to complicated shaped energy storage devices. Therefore, this complied study will help to select the PCM or PCM composite and in design of LHTES for a specific application.
... Some phase change materials such as salt hydrates can be cooled far below their melting temperatures without freezing, reaching a metastable supercooled state that can rapidly solidify and release energy upon the introduction or formation of a stable crystal nucleus 20 . Supercooled phase change materials have found applications as triggerable heat sources in the context of portable hand heating 21 , cold-start automotive engine heating 22 , building-scale air and water heating 23 , and long-term solar energy storage 24 . These applications are mostly intended to raise temperatures in a bulk volume for human comfort or improved device function; accordingly, the spatial and temporal evolution of the thermal profiles produced by triggerable phase change materials have rarely been engineered beyond the shape of the reservoir. ...
The crystallization of metastable liquid phase change materials releases stored energy as latent heat upon nucleation and may therefore provide a triggerable means of activating downstream processes that respond to changes in temperature. In this work, we describe a strategy for controlling the fast, exothermic crystallization of sodium acetate from a metastable aqueous solution into trihydrate crystals within a polyacrylamide hydrogel whose polymerization state has been patterned using photomasks. A comprehensive experimental study of crystal shapes, crystal growth front velocities and evolving thermal profiles showed that rapid growth of long needle-like crystals through unpolymerized solutions produced peak temperatures of up to 45˚C, while slower-crystallizing polymerized solutions produced polycrystalline composites and peaked at 30˚C due to lower rates of heat release relative to dissipation in these regions. This temperature difference in the propagating heat waves, which we describe using a proposed analytical model, enables the use of this strategy to selectively activate thermoresponsive processes in predefined areas.
... Heat accumulation with its subsequent use is the topic of many studies in recent years. To accumulate heat, heat accumulators (HA) have been developed [266][267][268]. The work of the heat accumulator is carried out due to the absorption (during melting) and release The question is that at low ambient temperatures during a layover of a car, for example, at night, there are difficulties with the engine start at the beginning of operation (so-called "cold start"). ...
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... Heat accumulation with its subsequent use is the topic of many studies in recent years. To accumulate heat, heat accumulators (HA) have been developed [266][267][268]. The work of the heat accumulator is carried out due to the absorption (during melting) and release The question is that at low ambient temperatures during a layover of a car, for example, at night, there are difficulties with the engine start at the beginning of operation (so-called "cold start"). ...
All rights reserved. Printed in the United States of America. No part of this publication may be reproduced, distributed, or transmitted, in any form or by any means, or stored in a data base or retrieval system, without the prior written permission of the publisher. The content and reliability of the articles are the responsibility of the authors. When using and borrowing materials reference to the publication is required. Collection of scientific articles published is the scientific and practical publication, which contains scientific articles of students, graduate students, Candidates and Doctors of Sciences, research workers and practitioners from Europe and Ukraine. The articles contain the study, reflecting the processes and changes in the structure of modern science.
... In the automotive industry, phase change materials (PCMs) have investigated in cooling of transmissions (Putrus et al., 2015), thermal comfort in vehicles , preheating of catalytic converters (Burch et al., 1995(Burch et al., , 1996Korin et al., 1999), preheating of an engine (Vasiliev et al., 2000(Vasiliev et al., , 1999Schatz, 1992), preheating of evaporator and pressure regulator (E&PR) of the liquefied petroleum gas (LPG) vehicle, and other applications in internal combustion engines (Gumus and Ugurlu, 2011;Boam, 1986). Gumus et al. developed about 2000 kJ of TES system for preheating of the internal combustion engine (Gumus, 2009). ...
Advances in Thermal Energy Storage Systems, 2nd edition, presents a fully updated comprehensive analysis of thermal energy storage systems (TES) including all major advances and developments since the first edition published. This very successful publication provides readers with all the information related to TES in one resource, along with a variety of applications across the energy/power and construction sectors, as well as, new to this edition, the transport industry. After an introduction to TES systems, editor Dr. Prof. Luisa Cabeza and her team of expert authors consider the source, design and operation of the use of water, molten salts, concrete, aquifers, boreholes and a variety of phase-change materials for TES systems, before analyzing and simulating underground TES systems.
... Phase change materials (known as PCMs) are functional materials that can be used in many applications, for instance solar applications [1][2][3], automotive industry [4][5][6][7][8], or buildings [9,10]. Generally, these materials exhibit high latent heats at melting temperatures, chemical/ thermal stabilities, as well as low toxicity and low thermal conductivities. ...
Polyethylene glycol is intensively studied as the base for new enhanced materials, while PEG 400 enhanced with nanoparticles may be seen as a new heat transfer fluid and its development is on its way. A number of reports were acknowledged in the recent literature, even if this research is ongoing and new hypothesis have to be further tested. This paper deals with a complex experimental study involving PEG 400 enhanced with three kinds of nanoparticles, i.e. Al2O3, ZnO and MWCNT. A first observation was in regard to a possible synergy between nanoparticle type and base fluid, yet this hypothesis requires to be further proved. The experimental was conducted taking into account both the temperature effect on the thermal conductivity, as well as the nanoparticle loading in the base fluid. Concluding, nanoparticles addition to a base fluid undoubtedly boosts its thermal conductivity, mechanisms being analogous to those demonstrated for all nanofluids. In regard to heating performance, it was perceived that upper nanoparticles concentration changes the heating comportment of the PEG 400.
... 20 Some phase change materials such as salt hydrates can be cooled far below their melting temperatures without freezing, reaching a metastable supercooled state that can rapidly solidify and release energy upon the introduction or formation of a stable crystal nucleus. 21 Supercooled phase change materials have found applications as triggerable heat sources in the context of portable hand heating, 22 cold-start automotive engine heating, 23 building-scale air and water heating, 24 and long-term solar energy storage. 25 These applications are mostly intended to raise temperatures in a bulk volume for human comfort or improved device function; accordingly, the spatial and temporal evolution of the thermal profiles produced by triggerable phase change materials have rarely been engineered beyond the shape of the reservoir. ...
The crystallization of metastable liquid “phase change materials” releases stored energy as latent heat upon nucleation and may therefore provide a triggerable means of activating downstream processes that respond to changes in temperature. In this work, we describe a strategy for controlling the fast, exothermic crystallization of sodium acetate from a metastable aqueous solution into trihydrate crystals within a polyacrylamide hydrogel whose polymerization state has been patterned using photomasks. A comprehensive experimental study of crystal shapes, crystal growth front velocities and evolving thermal profiles showed that rapid growth of long needle-like crystals through unpolymerized solutions produced peak temperatures of up to 45˚C, while slower-crystallizing polymerized solutions produced polycrystalline composites and peaked at 30˚C due to lower rates of heat release relative to dissipation in these regions. This temperature difference and propagating heat waves, which we describe using a proposed analytical model, enable the use of this strategy to selectively activate thermoresponsive processes in predefined areas.
... The heat storage technology employing the latent heat of the phase transition has been successfully applied in concentrated solar power systems, 4-6 the automotive industry for preheating internal combustion engines, 7,8 and civil engineering. 9 Using accumulators in solar energy systems provides a possibility to store the maximum amount of energy during the peak sun hours and use it during the rest of the day. ...
The current problem related to operation of nuclear power plants within power grids is caused by the base‐load level achieving its maximum. The growing share of NPPs in the power systems requires their involvement in the regulation of load curve irregularities. At the same time, operation of an NPP with the maximum installed capacity utilization factor is economically and technically scientifically grounded. According to the scheme of combining an NPP with a heat accumulator, during the nighttime decrease in electricity consumption, the main steam from the NPP steam generator flows for heating the heat storage material. During the peak‐load hours, the accumulated energy can be used to increase the capacity of the NPP power unit due to additional heating of the feed water. This research is based on the standard methods of thermodynamic and technoeconomic analysis. The conducted computational experiments include computer simulation by the finite element method. Investigation into economic efficiency of the technology included analysis of a wide range of electricity rate structures with particular account for a possibility to refuse from high‐priced PRHR heat exchangers due to additional emergency backup of NPP auxiliaries. The calculations show that the accrued net present value of the proposed system will amount $ 4.4‐12.5 million over the 25‐year accounting period under the accepted tariffs for the supplied peak and off‐peak electricity, in conditions of combining the system with NPP power unit containing a VVER‐1000 reactor. Schemes for combining the NPP with an installed VVER and a multifunctional heat accumulation system. Constructive solution of the heat accumulator design. Justification of economic efficiency of the schemes for combining nuclear power plants and heat storage systems.
... De Santis [46] investigated that PCM's can reduce the peak temperature during in-situ polymerization of the PMMA utilized for manufacturing of bone cement composites. Phase change materials are also used in the automobile sector for preheating catalytic converters, internal combustion engines, coolant for the engine, etc. [47][48][49][50][51][52][53][54]. PCM's are also investigated for their application in the food industry. ...
From the past decades, researchers are looking for advanced materials that will cut down the overuse of fossil fuels to decrease the negative impact on the environment. This paper aims to investigate the methods of harnessing energy from the advanced materials and their properties, types, and application in detail. Phase change materials having the potential to absorb or release the energy as latent heat and posses own phase temperature. PCM's are classified generally into three types organic, inorganic, and eutectics. We also review the applications of phase change materials in different sectors and recent advances from the material aspects are studied.
... When investigating waste heat recovery of engines, LTES using lowtemperature PCMs have been explored to improve the cold-start performance [166,167]. In contrast, little attention has been given to the applications of LTES using medium-high temperature PCMs in recovering waste heat of engine exhaust gas. ...
Thermal energy storage (TES) technology is considered to have the greatest potential to balance the demand and supply overcoming the intermittency and fluctuation nature of real-world heat sources, making a more flexible, highly efficient and reliable thermal energy system. This article provides a comprehensive state-of-the-art review of latent thermal energy storage (LTES) technology with a particular focus on medium-high temperature phase change materials for heat recovery, storage and utilisation. This review aims to identify potential methods to design and optimise LTES heat exchangers for heat recovery and storage, bridging the knowledge gap between the present studies and future technological developments. The key focuses of current work can be described as follows: (1) Insight into moderate-high temperature phase change materials and thermal conductivity enhancement 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.
... In the automotive industry, phase change materials (PCMs) have investigated in cooling of transmissions (Putrus et al., 2015), thermal comfort in vehicles , preheating of catalytic converters (Burch et al., 1995(Burch et al., , 1996Korin et al., 1999), preheating of an engine (Vasiliev et al., 2000(Vasiliev et al., , 1999Schatz, 1992), preheating of evaporator and pressure regulator (E&PR) of the liquefied petroleum gas (LPG) vehicle, and other applications in internal combustion engines (Gumus and Ugurlu, 2011;Boam, 1986). Gumus et al. developed about 2000 kJ of TES system for preheating of the internal combustion engine (Gumus, 2009). ...
In this chapter, the potential of thermal energy storage (TES) technology in the transport sector, especially vehicle applications, is described. There are various attempts to contribute to improving the performance of the conventional internal combustion engine vehicles as well as electric vehicles. Some of the most representative studies and approaching methods of researchers have been reviewed depending on the TES methods.
... Thermal storage of solar energy [5][6][7] Heating and sanitary hot water [8,9] Cooling [10][11][12][13][14][15][16] Thermal comfort in vehicles [17] Solar power plants [18][19][20][21] Cooling of engines [22] Thermal protection of electronic devices [23] Spacecraft thermal system [24] The performance of thermal storage systems was analyzed [25]. A south-oriented wall was used as thermal storage with phase change materials embedded in the wall. ...
Thermal energy storage (TES) is an essential part of a solar thermal/hot water system. It was shown that TES significantly enhances the efficiency and cost effectiveness of solar thermal systems by fulfilling the gap/mismatch between the solar radiation supply during the day and peak demand/load when sun is not available. In the present paper, a three-dimensional numerical model of a water-based thermal storage tank to provide domestic hot water demand is conducted. Phase change material (PCM) was used in the tank as a thermal storage medium and was connected to a photovoltaic thermal collector. The present paper shows the effectiveness of utilizing PCMs in a commercial 30-gallon domestic hot water tank used in buildings. The storage efficiency and the outlet water temperature were predicted to evaluate the storage system performance for different charging flow rates and different numbers of families demands. The results revealed that increases in the hot water supply coming from the solar collector caused increases in the outlet water temperature during the discharge period for one family demand. In such a case, it was observed that the storage efficiency was relatively low. Due to low demand (only one family), the PCMs were not completely crystallized at the end of the discharge period. The results showed that the increases in the family’s demand improve the thermal storage efficiency due to the increases in the portion of the energy that is recovered during the nighttime.
... Thus, it is possible to provide energy in a healthier way. Thermal energy storage application covers thermal storage of solar energy [1] and solar power plants [2] as well as cooling applications (engines [3], food protection [4], ice-bank [5] etc.), building applications [6], hot water providing [7], greenhause applications [8], spacecraft systems [9], smart textiles [10], etc. Energy can be stored in three different ways; sensible heat storage, latent heat storage and thermochemical heat storage [11]. ...
The imposed thermal energy is an important parameter to determine the melting time of PCM. Melting behavior of paraffin wax as a phase change material (PCM) positioned in anannular concentric cylindrical tube is investigated. The heat for melting of PCM is provided through the inner surface of the wax. Effect of the applied heat fluxes on total melting time of paraffin wax is investigated. In order to quantify the complete phase change time a clear definition for the complete melting time is developed and the duration of total melting is reported at different heat fluxes experimentally. Paraffin wax has possible applications in solar water heat collectors as a latent heat based thermal energy storage system and understanding of the melting/freezing behavior is important in the design of such systems. Another important point in the thermal analysis of phase change materials is to enhance its thermal conductivity. Therefore, knowing the melting time at a certain heat flux is useful when one decided to increase rate of heat transfer, so a suitable technique can be selected.
... The pre-heating of fuel, engine lubricant and/or coolant further improves the engine starting process in terms of reliability and efficiency, while reducing the cold-start extra emissions (Andrews et al., 2007;Roberts et al., 2014). Sensible and latent TES systems recovering the thermal energy from the exhausts have been demonstrated to improve the coldstart performance of engines (Jarrier et al., 2000;Vasiliev et al., 2000); however, they may not be suitable for emergency power systems where the engine operates just a few hours per year and thus successive heat charge/discharge phases could be far in time. ...
Thermal energy storage is a key technology to increase the global energy share of renewables—by matching energy availability and demand—and to improve the fuel economy of energy systems—by recovery and reutilization of waste heat. In particular, the negligible heat losses of sorption technologies during the storing period make them ideal for applications where long-term storage is required. Current technologies are typically based on the sorption of vapor sorbates on solid sorbents, requiring cumbersome reactors and components operating at below ambient pressure. In this work, we report the experimental characterization of working pairs made of various liquid sorbates (distilled water, ethanol and their mixture) and a 13X zeolite sorbent at ambient pressure. The sorbent hydration by liquid sorbates shows lower heat storage performance than vapor hydration; yet, it provides similar heat storage density to that obtainable by latent heat storage (40–50 kWh/m3) at comparable costs, robustness and simplicity of the system, while gaining the long-term storage capabilities of sorption-based technologies. As a representative application example of long-term storage, we verify the feasibility of a sorption heat storage system with liquid sorbate, which could be used to improve the cold-start of stand-by generators driven by internal combustion engines. This example shows that liquid hydration may be adopted as a simple and low-cost alternative to more efficient—yet more expensive—techniques for long-term energy storage.
... There was also a case study of a PCM-based cooling system for thermally stable operation in the transient state of the electric motor. A PCM with high thermal storability was used to maintain a low operating temperature in a harsh environment, such as in an environment where heat accumulates in an engine room due to insufficient outside air circulation [14][15][16][17]. Small electronic devices require higher cooling performance than large devices, and a hot spot due to excessive local heat can occasionally cause a critical problem during normal operation. ...
The thermal performance of phase change material (PCM)-based compact cascade cooling systems with an integrated heat sink was experimentally evaluated using heat-transfer measurements under constant heat flux. Numerical calculations were also performed to investigate the fundamental mechanism of the cascade cooling approach using multiple PCMs (i.e., paraffin wax) with different melting points. This structure facilitated cooling via hierarchical heat exchange without additional energy consumption. The experimental results of the cascade cooling system demonstrated that the peak temperature within a fin decreased from 123.4 to 107.2 °C in one heat-supply cycle owing to the latent heat adsorption during a phase change in the PCMs. Particularly, the cascade cooling system reduced the peak temperature by approximately 13.1% compared with natural convection in air. In addition, the time taken to reach the maximum allowed temperature from the peak temperature was decreased by 45.0% because of the larger heat capacity and cascading heat exchange of PCMs. This implies that the lifetime of a system can be increased and failure can be prevented. Improved thermal performance was demonstrated after repetitive heating–cooling cycles. Furthermore, it was numerically demonstrated that a PCM nanocomposite can reduce the heat accumulation because of the low thermal conductivities of PCMs.
... Vasiliev et al. [33] developed the latent heat storage module for motor vehicle because the heat is stored when the engine stopped, and can be used to preheat the engine on a new start. It is possible to reach an optimized working temperature within the engine in a much shorter time using the heat storage than without heat storage. ...
The objective of present work is to gather the information from the previous works on the phase change materials and latent heat storage systems. The use of latent heat storage system incorporating phase change material is very attractive because of its high energy storage density with small temperature swing. There are varieties of phase change materials that melt and solidify at a wide range of temperature making them suitable for number of applications. The different applications in which the phase change method of heat storage can be applied are also reviewed in this paper.
... Huntemann et al. [160] presented a reduction of gas emission at cold start of the engine with a use of different salt hydrates: a eutectic salt or sodium acetate trihydrate, with tetrasodium pyrophosphate decahydrate as an additive to prevent supercooling phenomenon. The same target was pursued by Vasiliev et al [161] who used NaOH·H2O with an unknown additive to reduce the gas emission of a bus. ...
Supercooling is an undesired property of phase change materials due to the poorly predictable occurrence of crystallization during cooling. For such situations, the stored latent heat cannot be recovered which can be an issue for temperature-controlled applications. This review illustrates the techniques used for triggering crystallization in phase change materials having a supercooling property. The development of triggering devices should constitute a breakthrough for heat on demand applications, as heat can be released even when the temperature drops far below the liquidus temperature. Several techniques appear to be promising for nucleation triggering. They have been classified into two categories: passive (reduction of supercooling) or active (triggering of crystallization on demand) devices. They were accurately investigated for water freezing for: meteorological comprehension, food preservation or the pharmaceutical industry. In this paper, several nucleating agents (passive) have been explored, and most of them, added by 1 wt%, can decrease the supercooling degree by more than 90%. In addition, the heat would be immediately released on demand from a supercooled material by the use of seeding or electrofreezing (active methods). Solidification can also be externally triggered by the application of high pressure or ultrasonic waves (active). In addition to the analysis of the efficiency of the different techniques in terms of supercooling reduction, this review also discusses the solidification process at a microscopic scale.
... PCM-heat exchanger systems have been designed, in some cases, with applications in mind. TES systems have been developed for the automotive sector as a way to reduce cold-start emissions of internal combustion engines by preheating the engine [66]. For example, Gumus [67] presents a cylindrical TES, 400 mm long and 220 mm in diameter, filled with smaller cylindrical copper tubes (diameter of 22 mm) filled with PCM (salt hydrate). ...
The use of phase change materials (PCMs) in energetic systems today is in large parts restricted by dynamic issues, or what could be termed the "rate problem"; i.e. how long will it take (heat transfer rate) to store, or recover, a given amount of thermal energy in a latent heat energy storage system (LHESS) for a specific application? There is no theory today that can easily answer that question. Therefore, this keynote paper focus on the work done currently in the PCM heat transfer community to better understand heat transfer within PCM-based thermal storage systems (TES), the study of application specific designs of PCM-TES, and the search for a theory to guide the design of those systems from a heat exchange point of view. To that affect, the study of a large number of different PCM-heat exchanger configurations is required to achieve the important long-term objective of determining heat exchanger design rules. For some decades now, numerous configurations of PCM-heat exchangers have been designed, built and studied; and important results and lessons from these studies will be presented and discussed. Furthermore, through the sum of all those results, the search for a PCM-heat exchanger's design theory is ongoing. This theory could follow traditional ε-NTU or LMTD methods, as some researchers have already tried, or require novel approaches. Fundamental questions are still unanswered: what are the important parameters for such theory? What are and how should the dimensionless numbers needed be defined? What reference temperature needs to be used for the PCM? This paper will ask many more questions and try to provide paths to determine some of the answers.
... Application of supercooled liquid to trigger and warm up the engine before ignition is reported in [8]. Before that, preheating a bus petrol engine from -10°C to 20°C in less than 7 min with 65 kg of sodium hydroxide hydrate (NaOH.H 2 O) was experimented by [64]. ...
Thermal energy storage is at the height of its popularity to harvest, store, and save energy for short-term or long-term use in new energy generation systems. It is forecasted that the global thermal energy storage market for 2015–2019 will cross US$1,300 million in revenue, where the highest growth is expected to be in Europe, Middle East, and Africa followed by Asia-Pacific region. Thermal energy storage has become an inevitable component of fluctuant renewable energy systems due to their significant role in increasing efficiency and Quality of Service (QoS).
... The maximum heat extracted using the heat exchanger under full load condition was around 3.6 kW. Vasiliev et al. [7] investigated a heat storage system for preheating a petrol engine operated under real conditions in cold weather. Subramanian et al. [8] experimentally investigated waste heat recovery from diesel engine exhaust, and they showed the advantages of a combined sensible and latent heat storage system. ...
... However, it did not receive much attention until the energy crisis of the late 1970s and early 1980s when it was extensively researched for use in different applications especially for solar heating systems . Although research into latent heat storage for solar heating systems continues [38][39][40][41], enormous work has been carried out to explore the use of PCMs in other applications, specifically, building air conditioning [42][43][44][45], underfloor heating system [46][47][48], building envelope [49][50][51] refrigeration system [52], electronics cooling [53][54][55], waste heat recovery [56][57][58], textiles [59,60], preservation of food, milk [61,62] to name a few. ...
Internal combustion engine inefficiencies and waste heat emissions raise environmental concerns, as they waste fuel energy in the form of heat, increasing fuel consumption and greenhouse gas emissions. Additionally, waste heat contributes to the urban heat island effect. Waste heat recovery is a vital solution, capturing and repurposing heat to reduce fuel use, emissions, and costs while promoting sustainability, innovation, and economic growth. Polygenerative waste heat recovery maximizes energy efficiency by generating multiple forms of energy from a single source, enhancing overall sustainability. The proposed Trinitor model is a polygenerative system encompassing power generation, product drying, space cooling/heating, and oxygen production. Power generation utilizes exhaust heat stored in a phase change material (PCM) to generate electricity through a Hot Air Turbine. The PCM also stores heat from the PVT thermal collector and supports produce drying. In the space cooling/heating process, the temperature contrast resulting from the hot air generated by the turbine and the cooled air from the Cooling chamber is harnessed by the Seebeck principle within the TEG, converting heat energy into electricity, and it is possible to create temperature variations using the Peltier Effect by supplying electricity. Oxygen production involves dehumidifying air, separating oxygen from hydrogen using an electrolyzer and storing oxygen for civilian use. A component review identifies SiC wall flow-diesel particulate filters (DPF), a paraffin-based Latent Heat Storage System, and electric-assisted turbo compounding as cost-effective for energy production. Produce drying relies on hot air or infrared drying, a revolving wicks humidifier, and a cooling coil dehumidifier. Space cooling/heating needs a water-type PV/T collector, MPPT charge controller, lithium-ion batteries, and ceramic TEGs. A PEM electrolyzer with appropriate components (bipolar plates, electrodes, catalyst, membrane, and gasket) enhances oxygen production efficiency. Based on existing literature, the trinitor has the potential to attain an overall efficiency ranging from 40.12–54.81%. Thus, a combination of low-efficiency processes results in a highly efficient waste heat recovery Trinitor system, with further improvements possible through identified components’ integration.
In this study, the phase transition process of porous carbon matrix (PCM) containing paraffin as phase change materials (PCM) in copper oxide nanoparticles (NPs) is explored utilizing the molecular dynamics (MD) simulation procedure. PCMs can cumulate and disseminate huge energy due to their high melting heat. In this way, the changes in the charge time, discharge time, heat flux (HF), and phase transition time are studied. The effects of the nanoparticles percentage and the initial temperature (T) on the thermal manner of the atomic sample are studied. The nanoparticle's atomic percentage from 1% to 5% enhanced the HF from 1452 to 1726 W/m² and decreased the phase transition time from 3.92 to 3.05 ns. So, the thermal manner of the atomic matrix progressed by increasing the percentage of nanoparticles, and phase transition occurred in a brief time. The initial T from 300 to 350 K enhanced the HF from 1452 to 1770 W/m² and reduced the phase transition time from 3.92 to 3.73 ns.
The cold start problem is still one of the most significant drawbacks of diesel engines, especially in cold climates despite all technological improvements of fuel injection and control systems. Starting diesel engines becomes more difficult at low ambient air and engine block temperatures. Moreover, the production of pollutant exhaust emissions increases during the cold start and warm-up period of the engine. In this study, the thermal energy storage system (TES) with phase change materials (PCMs) has been proposed to improve the cold start and warm-up performance and exhaust emission characteristics of diesel engines. The waste heat from the engine main coolant using as the heat source is transferred to TES with integrated PCM after the warm-up period of the engine for heat storage. Then, the latent and sensible heat stored in PCM is transferred to the engine manifold to increase the temperature of intake air during cold start. The experiments have been conducted under low dead state temperature (≈6 ⁰C) conditions of the engine block and ambient. The experimental and energy-exergy comparison analysis results show that the cold start cranking period, CO and HC exhaust emission performances have improved by approximately 68.2%, 27.5% and 44% compared to classical engine system with the use of a designed TES, respectively. The efficiency of the strategy of increasing the intake air temperature by designing a PCM-based TES is supported by energy and exergy comparison analysis. Thermal efficiency and exergy efficiency improved in the range of 1.02%-7.45% and 0.9%-9.63%, respectively. These improvements show that the performance of a diesel engine under cold start conditions can be improved with a PCM-supported TES system.
In current study, simulation based on FVM is examined to scrutinize the melting of paraffin within an air conditioning unit. To reach greater performance, shape of inner wall is considered as sinusoidal and pure paraffin mixed with copper oxide powders. Hot air inside the inner duct compensates the needed heat flux for melting. Outputs indicate that inclusion of nanomaterial speeds up the charging and can help the conduction mode. Utilizing wavy duct with greater a can expedite the melting and air can get warmer in lower time.
This research deals with solidification procedure of phase-changing material (PCM) in a Latent Heat Thermal Energy Storage System (LHTESS). Rectangular fin made of copper and triplex container are utilized in this study and also different volume fractions of Hybrid Nano-Particles (HNP) (TiO2-Go) are added to the water. In present research, water is regarded as PCM. The purpose of this research is to inquire the effect of HNPs, fins and shape factor of nanoparticles on acceleration of the solidification process. As an innovation, a new hexagonal geometry along with fins is employed in LHTESS. Galerkin Finite Element Method (GFEM) is applied to solve the governing equations and coding is carried out by an open source application. Results indicated that applying fins and HNPs reduces the full solidification time up to 12% and also using lamina shaped HNPs reduces the full solidification time up to 4% more than brick shaped.
Phase change materials (PCMs) have huge potential for latent thermal energy storage, waste heat recovery, heating, and cooling systems, due to their excellent thermal storage properties. However, the low thermal conductivity is most significant problem related with the PCMs, which retards the heat transfer rate and limits their practical applications. Heat pipe (HP) is extensively used heat transferring device, due to their ability to transfer heat isothermally over small and large distances. This review focuses on the systems that use a combination of PCM and heat pipes to enhance thermal performance and efficiencies. Overall efficiency, heat storage and release rate of PCM is reported to greatly improve by the integration of HP. These hybrid systems also have shown to overwhelm the issues such as low thermal conductivity of PCM and overheating of heat pipes.
This work is an experimental and computational study to investigate the effect of capacitive discharge ignition (CDI) on plasma kernel formation and flame propagation of air-propane mixture. This paper is mainly focused on the plasma formation and flame propagation characteristics, pressure rise, propagation time, velocity field, and species concentrations. A conventional ignition system is used for comparison purpose. A constant volume combustion chamber with volume of 400 cm3 is designed for experimental study. This chamber is utilized to visualize the plasma formation as well as the flame propagation induced from two ignition sources. The experiments are performed in a wide range of operating conditions, i.e., initial pressure of 2-4 bar, temperature of 300 K, chamber wall temperature of 350 K, spark plug gaps of 1.0-1.5 mm, discharge duration of 1 ms, discharge energy of 500 mJ, and equivalence ratio of 0.5-1.0. The computational study is performed by ANSYS fluent using the partially premixed combustion (PPC) model having the same conditions as experimental study. It is shown that the average peak pressure in CDI increased by 5.79%, 4.84% and 4.36% at initial pressures of 2, 3, and 4 bar, respectively, comparing with conventional ignition. It could be determined that the impact of combustion pressure in CDI system is more significant than conventional ignition particularly in lean mixtures. Consequently, the flame propagation rate in CDI system, due to the large ionized kernel around the spark plug, can be significantly enhanced.
In this study, the effect of heat flux and inclination angle variation in a rectangular PCM containing cavity is investigated. In order to investigate of effect of heat flux variation on melting process, the cavity is heated through the bottom plate by 3 levels of heat flux. Also to investigate the effect of inclination angle variation, 3 levels of inclination angle (0°, 45°, 90°) are considered. The changes of the liquid-solid boundaries are recorded using Canon G9 camera. 32 thermocouples at 9 heights of the container and 3 thermocouples on heater’s plate are implemented by which average temperature of the PCM, liquid fraction, average temperature of the heating surface, the amount of absorbed energy, temperature contour, the phases boundaries deformation, the average temperature at a specific distance of the heater and Nusselt number are analyzed. The results show that, as the heat flux input strengthens, melting time reduces and the rate of heat transfer and heater’s temperature increases. The driven Nusselt number implies that as the heat flux increases, the dominant heat transfer mechanism turns to natural convection sooner.
In this study, the efficiency of an LPG evaporator/regulator (E/R) is investigated on both energy and exergy concept. The E/R, which is a key part of LPG conversion systems that enables gasoline engines to be operated on LPG when desired, has been transformed to a thermal energy storage (TES) system using an adequate amount of phase change material (PCM) to be able to store waste energy of the engine coolant, so that the engine can be operated on LPG rather than gasoline even at cold start to decrease fuel consumption and exhaust emissions. The engine has been tested at idle speed at 4 °C environment temperature. The PCM application provided the engine to be operated on LPG at cold start and increased the efficiency of the E/R in a considerable extent on both energy and exergy bases. It was observed that using PCM in the E/R for thermal storage, the net efficiency differences of the E/R with PCM application reach to the values of 20% and 10%, respectively for the energy and exergy calculations. The net 2nd law efficiencies were lower than the ones that of 1st law with the values of about 11% for gasoline operation, and 8% for LPG operation of the engine.
This work aims to evaluate the performance of an integrated phase change material (PCM) solar collector. The dynamic behavior of the system is investigated via a theoretical model based on the first law of thermodynamics and oriented to deliver a maximum outlet water temperature. A parametric study is used to assess the effects of the inlet water temperature, the PCM thicknesses and properties and the mass flow rates on the outlet water temperature and the melt fraction. A comparison with a conventional solar water heater without heat storage is made. Results indicate that charging and discharging processes of PCM offer six stages. It is observed that the complete solidification time is longer than the melting one. The latent heat storage system increases the heating requirements at night. The rise is most enhanced for higher inlet water temperature, melting PCM temperature and PCM thickness and for lower mass flow rate.
The problem of environmental pollution and depletion of fossil fuel can be reduced in automotives by using an alternative bio-fuel and improve the ignition process in engine. Both solutions need to use the fuel preheating technique. This work presents the idea of fuel preheating by using exhaust impingement on the fuel tank. Heat transfer between twin pulsating hot air jets and flat copper target was investigated as an application for preheating of automotive fuel to improve ignition process in the engine. The nozzle of 20 mm was used to produce air jet of Reynolds number, Re ≃ 5500 and a temperature of 54°C. The impinged target was imposed to still air surrounding at temperature of 24°C. Pulsating frequencies of 10-50 Hz were applied on air jets by using twin pulsating jet mechanism. The effect of pulsation frequency on heat transfer was measured using IR camera and heat flux-temperature micro foil sensor. The results obtained by both of these methods showed well agreement. Also, the results revealed significant influence of flow rate difference between steady and pulsating jet cases. In addition, the highest Nusselt number, Nu ≃ 7.2, was obtained at pulsation frequency of 20 Hz.
This paper presents a review on thermal energy storage using Phase change material (PCM) and their applications. Latent heat thermal energy storage offers a huge opportunity to reduce fuel dependency and environmental impact produced by fossil fuel consumption. Solar energy is a renewable energy supply that can generate electricity, provide hot water, heat and cool a house and give lighting for buildings. In response to rising electrical energy costs, thermal storage technology has recently been developed. The selection of the substances to be used mostly depends upon the temperature level of the application. Phase change materials (PCMs) are one of the latent heat materials having low temperature range and high energy density of melting- solidification. Phase Change Materials (PCMs) are becoming more and more attractive for space heating and cooling in buildings, solar applications, off-peak energy storage, and heat exchanger improvements.
In this study, the waste heat recovery from a diesel engine was investigated and the heat storage tank and heat exchanger integrated into this system was discussed in terms of different phase change materials. The waste heat from the combined diesel engine system was stored in the phase change material (PCM) encapsulated in the cylindrical capsules into the heat storage tank by means of heat exchanger. The charging times of this system were theoretically determined for the different phase change materials. The calculations using the PCM approach model were performed for the different engine operating conditions (25%, 50%, 75% and 100%). The performance of the engine of the PCM and heat exchanger was analyzed with respect to the parameters, such as the amount of heat recovered, charging rate, and thermal efficiency, under different operating loads. The energy in the range of 10-21.69% is gained by storing of the waste heat in the combined system. It is found that, by using myristic acid instead of paraffin as PCM into a unified system, the thermal efficiency can be increased in the range of 4.144-6.456%. However, it is observed that by using acetamide, it decreases in the range of 6.844-9.880%. It is concluded that the charging time is important in the energy storage system with different phase change materials and this time can be reduced by changing the PCM.
Recently, a thermal management system (TMS) was considered to improve fuel economy by reducing energy loss and parasitic energy. Furthermore, the TMS includes waste heat recovery (WHR), which warms up engine coolant or transmission oil and obtain electrical or mechanical energy. In particular, the TMS is necessary-to resolve the drawback of hybrid electric vehicles (HEVs), as the transmission oil heats up more slowly compared to a conventional vehicle due to shorter engine operating time. In this report, a TMS with a WHR system was applied to supply heat source to the continuously variable transmission (CVT) oil of a HEV for a better operating region at the cold start condition. The research was performed using a simulation model, which consists of a thermal mass model, heat transfer model, friction model and waste heat recovery model with experimental data were used for validation. As a result, the simulation results showed that the CVT efficiency with the WHR model could be improved by as much as 2% with an oil temperature increase of 16 degrees C in the urban dynamometer driving schedule (UDDS) mode, and an additional 2-8% improvement in transmission efficiency could be achieved by expansion of the application area. (C) 2013 Published by Elsevier Ltd.
The development of a heat storage (HS) for pre-heating of the internal-combustion engine to start is represented as extremely urgent problem. Absence of warm garages and the above standard depreciation of a automobile machinery especially urban buses, forces maintaining organisations to search for new ways of facilitation of engines start-up in a cold period.
In this work a thermal accumulator (HS) working on the effect of absorption and rejection of heat energy at solid-liquid phase change of heat storage substance is discussed. In theoretical part a numerical method to calculate a heat storage device and its characteristics is described. In experimental part the laboratory installation simulating conditions for working of HS device and results of laboratory experiments are represented. Data on full-scale tests of pre-heating device to start carburettor engine in operational conditions of Minsk 1-st bus park and analysis of data received are given.
The work has a long prospect. The development of pre-heating device for starting more powerful diesel engines is supposed.
Problems associated with cold starts can be overcome by preheating the vehicle. A soon-to-be-introduced heat-management technology, called a heat battery, is one way to combat this problem. The heat battery collects and stores engine waste heat for release at restart days later. It provides improved emissions, warm-up performance, fuel consumption, and instant cabin heating and windshield cleaning.
The development of heat storage (HS) devices for pre-heating internal-combustion engines at start-up is presented as an extremely urgent problem. The absence of warm garages and the above-average depreciation of automotive machinery, especially urban buses, force maintenance organisations to search for new ways to facilitate engine start-up in cold periods. In this work, a thermal accumulator (HS) working on the effects of absorption and rejection of heat energy at the solid-liquid phase-change of the heat storage substance is discussed. In the theoretical part, a numerical method for calculating heat storage and the characteristics of heat storage devices is described. The experimental part describes the laboratory installation simulating conditions for the working of the HS device and presents the results of laboratory experiments. Data on full-scale tests of pre-heating devices for starting carburettor engines and an analysis of data received are given.
In an effort to identify the aspects of vehicle operation which have most influence on fuel consumption during the ECE 15 driving cycle an energy audit was carried out on a two-litre saloon car driving such a cycle. The most interesting results to emerge were that, in the first cycle, 12 per cent of the fuel passed through the engine either partially or completely unburnt, 8 per cent emerged as useful work, and 60 per cent was used to warm up the engine and transmission, while 10 per cent was rejected in the exhaust gas as heat.
Bearing in mind the large relative significance of problems involved in the removal of heat from the nuclear reactors and its conversion into other types of energy, the basic information on thermodynamics and heat transfer are treated. (Author)
An analytical evaluation of a thermochemical store using inorganic oxides as the storage material has been carried out. The possibility of using this device as a thermal store for minimising energy consumption and pollutants simultaneously from automobile engines during cold starting exists. Sources of heat from the exhaust and the cooling circuit are identified as potential energy input for regenerating the store. However, the viability of this device depends on addressing issues such as the life cycle of the storage material and the bed configuration of the store. Experimental validation is therefore needed.
Data are presented on the corrosion resistance of metallic alloys to hydrated salts, which may be utilized as phase change materials (PCM) for heat storage. With the same experimental apparatus, tests on the thermal performance reliability of PCM after repeated thermal cycling were carried out. Commercially available latent heat storage components containing the following salt hydrates with melting points between 15°C and 32°C have been considered: Na2SO4 · 10H2O, CaCl2 · 6H2O, , NaOH · 3,5H2O. The containment materials tested were stainless steel, carbon steel, Al alloys, and Cu. As many as 5650 thermal cycles involving repeated melting and freezing of the phase change materials were carried out. The most corrosion-resistant alloy to all the hydrated salts tested was stainless steel. Only the two commercial CaCl2 · 6 H2O tested showed good thermal stability after repeated thermal cycling.
Corrosion behaviour of same heat storage construction materials
- Á Panasienko
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913±923 Fig. 6. Schematic of the experimental HS device location in the bus LAZ-695N: (1) thermostat; (2) control block of the electrical pump; (3) outlet pipe of HS
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l/min. L.L. Vasiliev et al. / Applied Thermal Engineering 20 (2000) 913±923 Fig. 6. Schematic of the experimental HS device location in the bus LAZ-695N: (1) thermostat; (2) control block of the electrical pump; (3) outlet pipe of HS; (4) heat storage (HS);
Authorized dealership of BMW (GB) Ltd Chesterfield), Internal technology document
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Salt hydrates as a materials for latent heat storage
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