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The importance of thermal management of batteries and motors is rising as electric vehicles gain popularity. Three crucial technologies for the thermal control of electric car batteries are thoroughly examined in this study: LC, PCMC, and HPC. Each methodology exhibits distinct benefits and is tailored to specific use cases, yet it also presents its set of obstacles and complexities. This paper finds that combining these three technologies can provide a more comprehensive battery thermal management solution. Heat pipes can quickly dissipate heat from hot spots and reduce thermal gradients. Phase change materials can help smooth out temperature fluctuations by absorbing and storing excess heat under high-load conditions. Finally, LC systems can manage the overall heat load by circulating coolant to remove heat from the system and dissipate it into the environment. However, this integrated approach requires careful design and optimization, including consideration of the layout of the components, the heat-generating properties of the different components, and the properties of the selected coolant and phase change materials. Overall, the research in this paper provides valuable insight and opens up new perspectives for understanding and improving battery thermal management in electric vehicles. [ABSTRACT FROM AUTHOR]

Earth-to-air heat exchangers (EAHE) are passive technologies used to cool and heat buildings. This paper aims to review published research on this topic. The review has structured into several sections that focused on the use of numerical evaluation of the performance of the earth tube heat exchanger in the ventilation of the buildings. The review also dealt with the results of studies that concentrated on the heat exchanger performance within different burial depths, the impact of soil, climate characteristics on the heat exchanger performance, and the effect of the merging mechanism adopted with the building (direct or with the cooling and heating systems attached to it). Finally, the paper reviewed the final conclusions reached by the researchers. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) are an environmentally friendly energy source. One EV application uses Lithium-ion (Li-ion) battery cells. In practice, li-ion operation generates heat which will burden battery performance. Therefore, this review paper will discuss the battery thermal management system (BTMS). There are several methods of BTMS, but this paper review will only focus on air-cooled and liquid-cooled BTMS, where it is still rare to find a comparison of these two cooling methods. The goal is to know about the best cooling method. The results show that liquid-cooled BTMS is superior in uniform temperature distribution but is more complex, and fluid leakage can occur. In comparison, air-cooled BTMS has the advantage of a more accessible system, but the temperature distribution between batteries is less even. [ABSTRACT FROM AUTHOR]

The advancement in electronic fields make devices smaller but has high heat flux. Therefore, heat dissipation for electronic devices plays a significant role to ensure their safe and good performance. The heat dissipation components including the heat sink, fans eliminate the heat of electronic devices as soon as possible, or else chips will be damaged, malfunction, sort lifetime by overheating. However, it is difficult to predict its operating temperature. Therefore, the CFD based method has been popularly applied in this field to optimise the design, save time and display the temperature distribution of the electronic device. In this paper, a real cross-cut heat sink's dimension was obtained, and then its model was developed by Inventor software. After that, a CFD based investigation was conducted to evaluate its thermal performance. The simulation was carried out with different powers and air velocity as well as at two rotation angles such as:0o and 90o clockwise around X-axis to evaluate the operation parameters. The results show that this heat sink could be applied for electronic devices with a power lower than 6 W without the fan. The heat sink's thermal resistance can be reduced with the increase of air velocity. Even, the temperature of the 10W chip can go down from 87.5oC to 65oC when the velocity increases from 0 m/s to 0.25 m/s. Furthermore, at a 90o clockwise angle, chip temperature under natural convection is somewhat lower than that at a 0o angle. [ABSTRACT FROM AUTHOR]

In this paper, the study of titanium high-pressure spherical tank billets produced by wire-based electron beam additive manufacturing was carried out. The billets were produced with no active cooling. The macro- and microstructure of the billet material in the "as-built" state was investigated, and static tensile tests were performed to determine the mechanical properties. The studies showed that the thermal conditions of the 3D-printing process of such products lead to a significant decrease in the material strength compared to the target values for the Ti-6Al-4V alloy. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries has promising future in electric vehicles and storage of electricity. The two main issues with these batteries are the charging time and the heating problems. When we vary the discharging and charging rate of the battery, the temperature also increases/decreases respectively. Battery thermal management has a crucial role of maintaining life-cycle and performance of.battery. A battery thermal management system ensures thermal repeatability and prevents thermal runaway of battery. The paper presents the results derived from the experimentation undertaken with this purpose. An experiment was performed on Lithium-ion 18650 battery cells, which are charged with 2 C charging rate which are cooled with immersion cooling via dielectric fluid. The use of this BTMS ensures the thermal runaway is minimized and all the cells are cooled uniformly, which make sure that all the cells are working under desirable conditions. The simulation was verified with experimentally. [ABSTRACT FROM AUTHOR]

This paper presents the design and implementation of automatic cooling and cleaning system (ACCS) for PV modules to optimize the performance of the PV module based on electrical efficiency drop resulting from increased cell temperature at loading and dust accumulation on PV module s surfaces. An increase in PV module temperature causes a linear reduction in its performance, affecting electrical power generation. Pressurized water jets by nozzles are used to cool and clean the front surface of the PV module. The theoretical model of the PV module is verified by MATLAB/Simulink software. The operational performance of ACCS was recorded and analyzed. The experimental results showed before cooling, the maximum power produced by the PV module was 65.31W, while after cooling increased by 73.24W. Also, electrical efficiency yield of before cooling the rate of decreasing efficiency 0.052% per 1℃ while after cooling the efficiency increased by 0.13% for each decrease 1℃. [ABSTRACT FROM AUTHOR]

Elastomeric materials are broadly used for damping augmentation in variety of applications due to their simple design, low weight density and high reliability and low tensile strength. Generally, the components of elastomers are manufactured in large quantity through injection moulding process. However, when required in small numbers for the specific applications such as aerospace, ship building, biomedical engineering etc and also 000when required in complex shapes and higher accuracy manufacturing elastomeric components through injection moulding process turns out to be an expensive process due to higher initial cost. Under those circumstances machining appears to be a promising process due to its versatility and accuracy. On the other hand machining Elastomers in normal circumstances is not so easy due to high elastic deformation that occurs in the entire workpiece during machining which results in poor product quality. Cryo-cooling assisted machining provide solution to this problem which is nothing but an extended quenching process in the conventional heat treatment cycle in which high elastic property disappears temporarily. The present paper aims at brief literature survey on recent developments in cryogenic machining of elastomers. [ABSTRACT FROM AUTHOR]

This paper describes a numerical study of internal pin-fin cooling performance of a trailing-edge cutback configuration for gas turbine blade. The study was performed at two steps: first, to validate simulation results from an existing TE cutback cooling with staggered pin-fin arrays inside the cooling passage against experimental measurements. Three structured meshes were used for grid convergence and to evaluate film-cooling effectiveness and discharge coefficient; second, to investigate the pin-fin cooling performance with various blowing ratios. Simulations were performed by keeping the same initial and boundary conditions as the corresponding experiment. The results show that validation can be considered acceptable by keeping quality grid and its resolution in near wall regions. Both computational data of the adiabatic film-cooling effectiveness and the discharge coefficient are in fairly good agreement with the test data. The pin-fin array has important roles to promote flow turbulence activity inside the cooling passage, in addition to increase surface areas for heat transfer. Hence the turbulence intensity is more pronounced due to the existence of the pin-fin and it is concomitant with the coolant flow inside the wedge-shaped duct. [ABSTRACT FROM AUTHOR]

Spot cooling is the process of directing a stream of cool air into a designated equipment or a group of people. Using Air as a natural refrigerant in the Spot cooling application brings in fresh air into the building and cools the area. The method of cooling are many, but sustainability is the biggest concern of this industry. The available refrigerants in the market are either effecting ODP (Ozone Depletion Potential) or GWP (Global Warming Potential). The only way out is to introduce sustainable and natural refrigerants. The Hypothesis which is brought into this research is to study the different types of spot cooling techniques available in the industry and challenge it with natural Air as a refrigerant. Sustainability is a paramount importance of our existence. This paper brings in the aspect of using natural refrigerants in comparison with currently used Freon's. This paper tries to introduce spot cooling comparison for basic industrial application and warehouse. Usually in the industry machinist and some times even the machine is not cooled for different reasons. If the cooling is provided both the machinist and machine will have better productivity and performance output. The paper puts light on different ways of spot cooling and the parameters important of the application. Best Worst Method has been applied using industrial expert opinion was taken into consideration. The results were a well-defined application for industrial use for cooling machine is established. Which can act as reference for other researchers to follow. All industrial facilities, warehouses and areas where production work takes place can apply the result of this research paper. [ABSTRACT FROM AUTHOR]

In the paper the results of predicting the parameters of the of low emission reciprocating compressor stages with a linear drive unit (RCSLDU) are presented, the identifying feature of which are the increased piston stroke S, low frequency of the work cycles n and extremely low average speed of the piston sp = f(S, n) ≤ 0.5 m/s. This set of parameters a priori guarantees reduced wear of the seal elements of the pistons and intensive heat extraction from the gas to the cooling medium and encourages the increase of the compressor stages efficiency. On the other hand, the same set of parameters can lead to negative consequences linked to the mechanical friction influence, the growth of external leakages through the piston seals and internal leakages through the clearances in the closed valves. Differentiated impact assessment of each of the indicated factors on simultaneously flowing and interdependent working processes by an experiment is very problematic. Therefore, in this paper the author's program COMDET-M is used, based on mathematical modeling of operation processes in compressor (COM) and pressure-reducing (DET) volumetric machines and has undergone extensive evaluation test in a variety of domestic enterprises and organizations. The research subject is a 4-stage compressor RC (RK)-15/1-75 with linear drive unit, working on hydrogen containing gas mixture. The results of numerical analysis given in this paper allowed us to indicate and justify new qualitative and quantitative trends in the processes of heat and mass interchange specific for low-emission compressors with a linear drive unit and to propose ways of optimization of gas distribution bodies, providing for reduction of the contact path length of the sealing edge of valves in the closed position. The criterion of the accepted technical solutions perfection is the power-weight ratio of the compressor RC-15/1-75 in accounting for mechanical friction, leakage levels and heat transfer processes. [ABSTRACT FROM AUTHOR]

This paper describes the results of an experimental investigation aimed to st udy the machinability of AA7075 T6 (160 HV) for aerospace industry at high cutting speeds. The paper investigates the effects of different lubri-cooling strategies (cryogenic, M QL and dry) during high speed turning process on cutting forces, tool wear, chip morphology and cutting temperatures. The cutting speeds selected were 1000m/min, 1250m/min and 1500 m/min, while the feed rate values used were 0.1mm/rev and 0.3 mm/rev. The results of cryogenic and M QL application is compared with dry application. It was found that the cryogenic and M QL lubri-cooling techniques could represent a functional alternative to the common dry cutting application in order to implement a more effect ive high speed turning process. Higher cuttingparameters would be able to increase the productivity and reduce the production costs. The effects of the cutting parameters and on the variables object of study were investigated and the role of the different lubri-cooling conditions was assessed. [ABSTRACT FROM AUTHOR]

In general, the cooling phase of the high-pressure die casting process is based on complex physical phenomena: solidification of molten material; heat exchange between cast part, die and cooling fluid; turbulent flow inside the cooling channels that needs to be considered when computing the heat flux; interdependency of properties and temperature of the cooling liquid. Intuitively understanding and analyzing all of these effects when designing HPDC dies is not feasible. A remedy that has become available is numerical design, based for example on shape optimization methods. However, current computing power is not sufficient to perform optimization while at the same time fully resolving all physical phenomena. But since in HPDC suitable objective functions very often lead to integral values, e.g., average die temperature, this paper identifies possible simplifications in the modeling of the cooling phase. As a consequence, the computational effort is reduced to an acceptable level. A further aspect that arises in the context of shape optimization is the evaluation of shape gradients. The challenge here is to allow for large shape deformations without remeshing. In our approach, the cooling channels are described by their center lines. The flow profile of the cooling fluid is then estimated based on experimental data found in literature for turbulent pipe flows. In combination, the heat flux throughout cavity, die, and cooling channel can be described by one single advection-diffusion equation on a fixed mesh. The parameters in the equation are adjusted based on the position of cavity and cooling channel. Both results contribute towards a computationally efficient, yet accurate method, which can be employed within the frame of shape optimization of cooling channels in HPDC dies. [ABSTRACT FROM AUTHOR]

Mould designers have been struggling for the improvement of the cooling system performance, despite the fact that the cooling system complexity is physically limited by the fabrication capability of the conventional tooling methods. However, the growth of Solid Free Form Technology (SFF) allow the mould designer to develop more than just a regular conformal cooling channel. Numerous researchers demonstrate that conformal cooling channel was tremendously given significant result in the improvement of productivity and quality in the plastic injection moulding process. This paper presents the research work that applies the passive enhancement method in square shape cooling channel to enhance the efficiency of cooling performance by adding the sub groove to the cooling channel itself. Previous design that uses square shape cooling channel was improved by adding various numbers of sub groove to meet the best sub groove design that able reduced the cooling time. The effect of sub groove design on cooling time was investigated by Autodesk Modlflow Insight software. The simulation results showed that the various sub groove designs give different values to ejection time. The Design 7 showed the lowest value of ejection time with 24.3% increment. The addition of sub groove significantly increased a coolant velocity and a rate of heat transfer from molten plastic to coolant. [ABSTRACT FROM AUTHOR]

The temperatures of the condensers' cooling media (water and air) can vary in a wide range depending on the ship's route. For example, on the route from Odessa to Hopen (Norway), the water temperature changes in the range from 18 ° C to -2 ° C, and air does from 20 ° C to -13 ° C (according to the data for April 13, 2018). Therefore, the well-known recommendations for determining the condensation temperature in the existing calculation methods cannot be applied to a refrigeration unit with composite cooling condensers because they provide different condensation temperature values. To determine the condensation temperature and study the operation of the marine refrigeration unit with composite cooling, a technical-and-economic calculation methodology has been developed. This methodology includes the calculation peculiarities of the composite condenser cooling, the cost of the main refrigeration equipment, the electricity cost and climate data for the ship's route. This method solves the problem of determining the condensation temperature to calculate the condensers and compressors of a marine refrigeration unit. The paper shows the results of the parametric analysis performed for a marine refrigerating unit for the route Odessa – Hopen. The recommended design value for the condensation temperature was 27°C (which corresponds to a pressure of 1066 kPa). It has been proven that the condensation temperature can be precisely determined for a composite condenser cooling at constantly changing cooling medium temperatures, while the technical-and-economic parameters of the refrigerating unit will be optimal. New design values of condensing pressures (temperatures) are obtained to calculate and select heat-exchange surfaces of refrigerating unit's condensers. [ABSTRACT FROM AUTHOR]

The blown film extrusion is a significant manufacturing process of plastic films. Compared to other extrusion processes, the productivity is limited by the cooling of the extrudate. A conventional cooling system for the blown film application provides the cooling air tangentially, homogeneous over the whole circumference of the bubble, using a single or dual lip cooling ring. In prior works, major effects could be identified that are responsible for a bad heat transfer. Besides the formation of a boundary sublayer on the film surface due to the fast flowing cooling air, there is the interaction between the cooling jet and the ambient air. In order to intensify the cooling of a tubular film, a new cooling approach was developed, called Multi-Jet. This system guides the air vertically on the film surface, using several slit nozzles over the whole tube formation zone. Hence, the jets penetrate the sublayer. To avoid the interaction with the ambient air, the bubble expansion zone is surrounded by a housing. By means of a numeric investigation, the novel cooling approach and the efficiency of the cooling system could be proved. Thereby, a four times higher local heat transfer coefficient is achieved compared to a conventional cooling device. In this paper, the Multi-Jet cooling system is experimentally tested for several different process conditions. To identify a worth considering cooling configuration of the novel cooling system for the experiment, a simulation tool presets the optimal process parameters. The comparison between the results of the new and a conventional system shows that the novel cooling method is able to gain the same frost line height using a 40% lower cooling air volume flow. Due to the housing of the tube formation zone, a heat recovery can be achieved. [ABSTRACT FROM AUTHOR]

Buildings and activities in buildings contribute to a major share of global environmental degradation. Hence the incorporation of sustainable technologies in domestic building cooling is the urgent need of the hour. Passive and energy efficient active building cooling methods are closely linked to human comfort of the residents by reducing the heat gains, maintaining the thermal balance and removing the internal heat from buildings. A comprehensive study focussing on sustainable building cooling technologies for building sector is presented in this paper. [ABSTRACT FROM AUTHOR]

In this paper we will present the design of a laboratory assembled portable EDXRF spectrometer that uses the secondary target excitation mode and its analytical performance. In secondary target configuration, the sample is excited mainly with the target material characteristic emission radiation, which allows to reduce the detected continuum background and to improve the detection limits. The instrument is based on a low power, air cooled, Ag anode X-ray tube (Eclipse III) and thermoelectrically cooled Si-PIN detector arranged in a specially built geometrical setup that allows the use of secondary targets. In our design, all spectrometer elements (x-ray tube, secondary target, sample and detector) are arranged in such a way that distances are minimal while keeping the excitation and detection angles optimal as well (φ = φ = 45°). The possibility to use different secondary targets enables the optimization of detection limits for different groups of elements in various types of samples. Examples of the application of the spectrometer for the analysis of different kind of samples will be presented. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to examine energy efficiency through the study of performance in vapour compression cycle for auditorium in University of Indonesia using natural refrigerant R290. The installation of the chiller system which is the first in Indonesia within academic institution is particularly relevant in light of the gaining interest and research regarding the implementation of refrigeration system utilizing relatively low ODP and GWP refrigerant as alternative to replace the refrigerant HCFC-22. It is found that the highest COP during 64% partial cooling load is 4.27 at temperature water inlet is 8.9ºC. The maximum COP during 75% partial load is 5.25 at temperature water inlet is 6,8 ºC. The cooling capacity are 125.93 kW and 148.39 kW during 64% and 75% load, respectively. [ABSTRACT FROM AUTHOR]

Over the last century, fresh water and cooling demand have been increased tremendously due to improved living standard, industrial and economic development. The conventional air-conditioning and refrigeration processes consume 15% of total global electricity and it is expected to increase any fold due to harsh weather conditions. In terms of fresh water supplies, the current 38 billion m3 per year desalination capacity is projected to increase to 54 billion m3 per year by 2030, 40% more compared to 2016. The current business as usual trend of cooling and desalination is not sustainable due to high energy consumption and CO2 emissions. In contrast, the adsorption (AD) cycle operate at low-grade waste heat or renewable energy and produce fresh water and cooling simultaneously. The major bottleneck of conventional thermally driven AD cycle is its large foot print and capital cost due to complex packed bed arrangements. We proposed pressure swing adsorption cycle (PSAD) that can utilize low-pressure steam (2-5 bar) for regeneration using thermal vapor compressor (TVC). The proposed system has best thermodynamic synergy with CCGT plants where low-pressure bleed steam can be utilized more efficiently to produce cooling and water. In this paper, a preliminary experimental investigation on PSAD has been presented. It is successfully demonstrated that 2 bar primary steam can regenerate silica gel at less then 0.5 kPa through TVC with compression ratio 3-4 and entrainment ratio around 1-1.5. The discharge steam can be re-utilized to operate the desalination cycle, maximizing the bleed steam exergy. The proposed system will not only reduce footprint but also CAPEX and OPEX due to simple design and operation. [ABSTRACT FROM AUTHOR]

There is a common misconception that all central systems are only operating in full-load conditions where in fact, most central systems are have the control system that can adjust the operating condition with the cooling loads. Customers tend to choose the air conditioning systems based only on full-load ratings despite a system may have different ratings on different load profiles. These differences can result in more expensive annual energy cost. The goal of this research is to develop an equation to provide customers with the part-load efficiency ratings of central air conditioning system (chiller) as an addition to full-load efficiency ratings provided by air conditioner companies. Non-standard Part Load Value (NPLV) is an equation to obtain part-load efficiency of a system which coefficients vary with location of interest. In this paper, NPLV for city of Jakarta, Bandung, Pontianak, Kupang, and Palembang were determined by Degree-Hours Method and Radiant Time Series Method. The results are compared and discussed. [ABSTRACT FROM AUTHOR]

The needs for clean and safe water are growing as the population growing as well. This paper describes the variation of Wastewater Percentage and Pinch Point Temperature Difference (PPTD) on a 50 MW Steam Power Plant. After using the cooling water, not all water is discharged back to the sea, some of the water are used in throttling process where some of water will be vapor, and the other are merged with the water from water treatment and are going to be used for cooling cycle. It’s found that by decreasing the condenser pressure from 8.45 kPa to 6.45 kPa it will produce vapor that could be condense into Aquadest with SEC (Specific Energy Consumption) at best condition as much as 697.85 kJ for producing 1 kg of Aquadest on PPTD 4.3 °C. On that condition, Aquadest could be produced at 0.0178 kg/s rate and the efficiency of turbine increase about 0.16%. Another benefit of this system is that this system discharges cooler water from the process, and has less impact to the environment. [ABSTRACT FROM AUTHOR]

Magnetically sensitive sensors are increasingly used in different applications for the measurement of physical values, such as angle, position or speed. Depending on the application certain requirements for a high measurement accuracy have to be achieved, such as a high pole length accuracy and repeatability for the signal transmitter. These signal transmitter can be produced economically in the injection molding process using compounds consisting of hard magnetic particles embedded in a polymer matrix, so-called polymer bonded magnets. By integrating a magnetic field inside the mold an orientation of the particles in the polymer melt as well as a partial magnetization can be conducted, such that the second magnetization step is not required. This paper deals with the influence of the cooling conditions on the orientation of the particles as well as the final magnetic properties, such as the resulting pole length accuracy. The cooling conditions are varied by using different materials for the cavity wall. It can be shown that the cooling of the surface layer and resulting particle orientation has a major influence on the quality criteria of injection molded signal transmitter for sensor applications. [ABSTRACT FROM AUTHOR]

To meet the full 2 ms 50 Hz 60 mA beam requirements for the Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL), a new caesiated Penning Surface Plasma Source (SPS) has been developed [1] with a larger plasma volume with 2X the linear dimensions of the standard ISIS source. This paper outlines the design decisions made during the development process and details the 2X source construction. Improved electrode cooling is required to operate at higher duty cycles, this is achieved by changing coolant, adding parallel cooling channels, improving mechanical tolerances, decreasing surface roughness and adding thermal interface gaskets. To operate at higher duty factors the ancillary hardware also required significant upgrading. A clean 75 mA H– beam has been measured from the 2X Scaled Source on a test stand at full 2 ms 50 Hz duty cycle. At lower 800 μs duty cycles H– beam currents of 150 mA have been measured at high discharge currents. Emittance scans and a perveance sweep are shown. [ABSTRACT FROM AUTHOR]

In this paper the temperature changes near the interface of explosively welded plates at the cooling stage are studied by numerical simulation. The temperature field in explosively welded materials was simulated in Autodyn software using smooth particle hydrodynamics (SPH) solver. This temperature field was subsequently used as initial conditions for the heat problem. The heat problem was solved using finite difference method by self-developed computer code. The simulation shows, that the cooling rate during explosive welding is comparable with that, achieved in rapid solidification techniques. The variations in cooling rate at different positions at the interface are discussed. The highest cooling rates are typical for small regions of molten material. [ABSTRACT FROM AUTHOR]

This paper describes the experimental study of performance of cold heat exchanger (CHX) in standingwave thermoacoustic heat engine. The engine is developed using commonly stainless-stell alloy and employ the atmospheric air as the working fluid. The engine generate acoustic wave at 300-400°C temperature difference which imposed between the hot and cold part of the system. The distribution of temperature of cold heat exchanger at inlet and outlet obey the condition of heat transfer where the temperature outlet is higher than temperature inlet because the water carry away all the heat being rejected at the end of the stack. The effectiveness of cold heat exchanger rejecting all the heat is 0.68 at the onset temperature. The range of effectiveness is 0.66 < η < 0.96 and become saturated at 12 minutes and forward after the experiment started with the value of 0.66. A simplified energy-balance theory adequately predicted a trend in temperature difference for acoustic wave onset, while underestimating actual values. The data presented here would be off interest to other researchers to further study the standing-wave thermoacoustic engine for further improvement. [ABSTRACT FROM AUTHOR]

This paper analyzes the performance of a split air conditioner at various condensing temperature under the constant cooling capacity. The nominal capacity of the air conditioning unit is 5.06 kW and the refrigerant is R-410a. The simulation shows that the increase of the condensing temperature causes the unit require the higher volumetric and mass flow rate of refrigerant to maintain the constant cooling capacity. The condenser capacity and the work of compression increase as well. On the other hand, the refrigerating effect decreases so that the overall performance of the air conditioning unit decreases. [ABSTRACT FROM AUTHOR]

A small modular nuclear reactor with passive safety features is one of the best solutions for Indonesian energy security to support the national sustainable development as in National Medium Term Development Plant (RPJMN) 2015- 2019. High safety level which shown by a small radioactive release to the environment on various probable accident is the basic scientific consideration beside the economic. Reaktor Daya Eksperimental (RDE) is a 10MWt small modular nuclear reactor applying pebble bed high temperature reactor design. RDE is dedicated as a basic reference and milestone for Indonesia to become a Nuclear Power Technology Provider in the near future. Cooling passive safety features, the capability of nuclear reactor to maintain its cooling performances only by natural mechanism with no external support, is very important feature to survive even in the severest condition as occur in Fukushima accident. This paper presents the cooling passive safety features of RDE in the severest accident scenario called depressurized loss of forced cooling (DLOFC). In DLOFC, the helium which cooled the core reactor is not available as a combination of circulator shutdown and breaks which occur in the primary system. The safety analysis simulation was performed using PEBBED code including the neutronic and thermal hydraulic solver. The analysis results show that in steady-state equilibrium condition the average and maximum fuel temperature is 511.9 ⁰C and 819 ⁰C. When the DLOFC accident is initiated, the core temperature is increasing. After 8.2 hours, the core reach its maximum temperature at 974.9 ⁰C and then decrease subsequently. The results show the cooling passive mechanism of RDE. Combine with the TRISO-based design of RDE, which able to contain the radioactive isotopes provided the fuel temperature is under the limiting value of 1620 ⁰C, the cooling safety feature ensure the safety design target of RDE that there is no dangerous radioactive release to the workers, populations, and environments even in the severest accident. [ABSTRACT FROM AUTHOR]

Recent studies have shown that machining under specific cooling and cutting conditions can be used to induce a nanocrystalline surface layer in the workspiece. This layer has beneficial properties, such as improved fatigue strength, wear resistance and tribological behavior. In machining, a promising approach for achieving grain refinement in the surface layer is the application of cryogenic cooling. The aim is to use the last step of the machining operation to induce the desired surface quality to save time-consuming and expensive post machining surface treatments. The material used in this study was AISI 304 stainless steel. This austenitic steel suffers from low yield strength that limits its technological applications. In this paper, liquid nitrogen (LN2) as cryogenic coolant, as well as minimum quantity lubrication (MQL), was applied and investigated. As a reference, conventional flood cooling was examined. Besides the cooling conditions, the feed rate was varied in four steps. A large rounded cutting edge radius and finishing cutting parameters were chosen to increase the mechanical load on the machined surface. The surface integrity was evaluated at both, the microstructural and the topographical levels. After turning experiments, a detailed analysis of the microstructure was carried out including the imaging of the surface layer and hardness measurements at varying depths within the machined layer. Along with microstructural investigations, different topological aspects, e.g., the surface roughness, were analyzed. It was shown that the resulting microstructure strongly depends on the cooling condition. This study also shows that it was possible to increase the micro hardness in the top surface layer significantly. [ABSTRACT FROM AUTHOR]

Heat generation is an inevitable phenomenon during machining. To eradicate heat oriented detrimental effects like surface burning, tool wear and so on- different types of cooling system are being used. Traditional flood cooling method is the most widely used technique; however the consumption rate of coolant is very high. Moreover, if it is not deposited or recycled properly, it may also cause environmental hazard. Minimum Quantity Lubrication (MQL), on the other hand, sprays lubricant which decreases the frictional force and heat produced during machining. Nanofluid MQL is the incorporation of especially engineered nanoparticles into the lubricant that increases the heat carrying capacity. In this paper, four manufacturing processes (grinding, turning, milling, and drilling) and the effect of using nanofluid MQL in them are studied and summarized. Parameters that are considered in this study are cutting force, surface roughness, machining temperature, tool wear and environmental aspects. It can be observed that using nanofluids in an optimized manner can be beneficial to the machining processes because of their superior characteristics. [ABSTRACT FROM AUTHOR]

Optimisation of temperature management in postharvest operations, such as precooling, requires extensive experimental measurement. For this purpose, real fruit are used, but due to their relatively high cost and perishable nature, commercial scale trials are not easily conducted. In addition, significant variability between trials exists (Vigneault et al., 2005). Physical fruit analogues or simulators could provide a solution to overcome these issues. To be a solution the fruit simulators must be designed to mimic the relevant heat transfer modes and properties of individual and/or bulk fruit, ideally using an inexpensive and durable material that allows the fruit simulator to be mass produced (Redding et al., 2016). In this paper, we use a mathematical model to characterize the relative importance of the different heat transfer modes occurring during precooling. Based on this model, the modes of heat transfer that must be matched by the fruit simulator are identified. A simplified model is used, representing four fruit stacked on top of each other in a column. The contribution of each heat transfer mode can be evaluated by including or excluding terms in the model. [ABSTRACT FROM AUTHOR]

This paper is concerned with using solar panels as high-tech cladding materials on multi-angled facades for office buildings. The energy produced by the solar panels will be consumed inside the office rooms by cooling compressors, ventilation, lighting and office equipment. Each multi-angled facade unit is directed into two different orientations on a vertical axis (right and left), but not tilted up and down. The different facade orientations will optimize the use of solar radiation to produce the needed energy from the solar panels when placing them on the parapets of these facades. In this regard, four scenarios with different facade configurations and orientations are evaluated and discussed. The method for the simulations and calculations depends on two main programs: first, IDA ICE program to calculate the energy consumption and evaluate the indoor climate of the building; and second, PVBAT to calculate the cost of the electricity produced by the solar panels and evaluate the total amount of energy produced from these panels along with the ratio to the energy bought directly from the electricity grid. There is also an environmental evaluation for the system by calculating the CO2 emissions in the different scenarios. [ABSTRACT FROM AUTHOR]

A novel method for generating GigaGauss solenoidal fields in a laser-plasma bubble, using screw-shaped laser pulses, has been recently presented. Such magnetic fields enable fast synchrotron radiation cooling of the beam emittance of laser-plasma accelerated leptons. This recent finding opens a novel approach for design of laser-plasma FELs or colliders, where the acceleration stages are interleaved with laser-plasma emittance cooling stages. In this concept paper, we present an outline of what a staged plasma-acceleration FEL could look like, and discuss further studies needed to investigate the feasibility of the concept in detail. [ABSTRACT FROM AUTHOR]

Modern high-tech equipment requires precise temperature control and effective cooling below the ambient temperature. Greater cooling efficiencies will allow equipment to be operated for longer periods without overheating, providing a greater return on investment and increased in availability of the equipment. This paper presents application of the Lz-transform method to importance assessment of aging multi-state water-cooling system used in one of Israeli hospitals. The water cooling system consists of 3 principal sub-systems: chillers, heat exchanger and pumps. The performance of the system and the sub-systems is measured by their produced cooling capacity. Heat exchanger is an aging component. Straightforward Markov method applied to solve this problem will require building of a system model with numerous numbers of states and solving a corresponding system of multiple differential equations. Lz-transform method, which is used for calculation of the system elements importance, drastically simplified the solution. Numerical example is presented to illustrate the described approach. [ABSTRACT FROM AUTHOR]

In view of the large power of armored vehicle cooling system, the demand for high fan speed control and energy saving, this paper expounds the basic composition and principle of hydraulic-driven fan system and establishes the mathematical model of the system. Through the simulation analysis of different parameters, such as displacement of motor and working volume of fan system, the influences of performance parameters on the dynamic characteristic of hydraulic-driven fan system are obtained, which can provide theoretical guidance for system optimization design. [ABSTRACT FROM AUTHOR]

Microstructure of post-homogenization is significant to prevent particle stimulated nucleation of recrystallization during hot deformation. This paper investigated microstructure evolution in an Al-6.3Zn-2.3Mg-2.2Cu- 0.10Zr alloy during homogenization and subsequent cooling. The as-cast microstructure of Al-6.3Zn-2.3Mg-2.2Cu- 0.10Zr alloy consists of α-aluminum dendrite with complex inter-metallic compounds segregated into the inter-dendritic regions. The main inter-metallic compounds formed during casting were MgZn2, Al2CuMg, Al7Cu2Fe and Mg2Si. After homogenization, the dendrite network disappeared completely, the MgZn2 and Al2CuMg phases were dissolved into the Al matrix. Two intermetallic phases, Al7Cu2Fe and Mg2Si were insoluble during homogenization. After homogenization and cooling to 400°C followed by quenching, precipitates nucleated discontinuously on the grain boundaries, no precipitates was found within the grains. The precipitates were found near the grain boundaries when quenching from 350°C, and the precipitates uniformly distributed within the center of the grains when quenching from 250°C. [ABSTRACT FROM AUTHOR]

The effects of cooling rate and pH on the potassium dihydrogen phosphate crystallization process were studied by means of batch crystallization process. The experiment shows that with the increase of cooling rate, the metastable zone width increase and the induction period decrease. When the pH is 3.0, the metastable zone width and induction period are both the minimum, while the crystallization rate is the highest. The crystallization products were characterized by scanning election microscope. Potassium Dihydrogen Phosphate (KDP) is a kind of excellent nonlinear optical materials, and belongs to tetragonal system, and ideal shape is aggregate of tetragonal prism and tetragonal dipyramid, the (100) cone is alternating accumulation by double positive ions and double negative ions [1-4]. The crystals of aqueous solution method to grow have large electro-optical nonlinear coefficient and high loser-damaged threshold, and it is the only nonlinear optical crystal could be used in inertial confinement fusion (ICF), KDP crystals are the ideal system to study the native defects of complex oxide insulating material [5-7]. With the development of photovoltaic technology, KDP crystals growth and performance have become a research focus worldwide [8, 9]. The merits of the crystallization process directly affect the quality of KDP products, so the study of the effect of crystallization conditions has an important significance on industrial production. This paper studied the change rule of metastable zone width, induction period, crystallization rate and particle size distribution in crystal process, and discussed the technical condition of KDP crystallization. [ABSTRACT FROM AUTHOR]

This paper presents the design, manufacture and electrical test of a novel integrated III:V low concentrator photovoltaic and thermoelectric device for enhanced solar energy harvesting efficiency. The PCB-based platform is a highly reliable means of controlling CPV cell operational temperature under a range of irradiance conditions. The design enables reproducible data acquisition from CPV solar cells whilst minimizing transient time for solid state cooling capability. [ABSTRACT FROM AUTHOR]

The paper deals with the impact of technological parameters on the heat transfer coefficient and microstructure in AlCu4Ti alloy using squeeze casting technology. The casting with crystallization under pressure was used, specifically direct squeeze casting method. The goal was to affect crystallization by pressure with a value 100 MPa. The pressure applied to the melt causes a significant increase of the coefficient of heat transfer between the melt and the mold. By rapid cooling the casting was reflected by changes in the structure. On the basis of the measured values of heat flux and heat transfer coefficient were calculated at the interface between the cast and the mold. The observation of microstructure can conclude, there is no significant influencing of the primary phase. As a result of the pressure was reduced porosity. [ABSTRACT FROM AUTHOR]

Hot tearing during solidification of aluminium alloys castings can be a serious problem. This phenomenon is well known but still insufficiently investigated. Hot tearing occurs in form of irregular cracks in metal castings that develop during solidification and cooling. The cause of hot tearing is generally attributed to the development of thermally induced tensile stresses and strains in a casting as the molten metal contracts during solidification and solid state shrinkage. Submited paper consists of two parts. The first part introduces the reader to the phenomenon of hot tearing. The second part describes newly developed method for assessing hot tearing susceptibility of aluminium alloys, and also gives the results on hot tearing for various aluminium alloys. [ABSTRACT FROM AUTHOR]

A magneto-optical trap of neutral atoms is essentially a dissipative quantum system. The fast thermal atoms continuously dissipate their energy to the environment via spontaneous emissions during the cooling. The atoms are, therefore, strongly coupled with the vacuum reservoir and the laser field. The vacuum fluctuations as well as the field fluctuations are imparted to the atoms as random photon recoils. Consequently, the external and internal dynamics of atoms becomes stochastic. In this paper, we have investigated the stochastic dynamics of the atoms in a magneto-optical trap during the loading process. The time series analysis of the fluorescence signal shows that the dynamics of the atoms evolves, like all dissipative systems, from deterministic to the chaotic regime. The subsequent disappearance and revival of chaos was attributed to chaos synchronization between spatially different atoms in the magneto-optical trap. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of the pulsating film cooling at the leading edge of a symmetrical turbine blade model. Numerical finite volume method is used to resolve the Unsteady Reynolds Averaged Navier Stokes Equations coupled at turbulence model. Detailed numerical film cooling effectiveness have been made for both steady and pulsating flows. The test case blade model is symmetric and has one injection row of discrete cylindrical holes on each side near the leading edge. Jet pulsing frequencies of 5 Hz, 10 Hz, and 20 Hz have been studied. The computational domain is discretized using a highly refined multi-bloc structured grid including the plenum area. The turbulence field is resolved by use of the SST turbulence Model. The numerical simulations are conducted for three different blowing ratios of 0.3, 0.5, and 0.7; film cooling effectiveness contours on the blade surface and lateral averaged adiabatic film cooling effectiveness are presented and the continuous jet results compared with available measurements. In addition to validation data, several longitudinal and transversal contours and vector planes are reproduced. It was found mainly that pulsating for low blowing ratios, cold jet decreases the film cooling effectiveness with no effect of frequency levels. [ABSTRACT FROM AUTHOR]

The paper deals with the cooling solution of the concentrated photovoltaic panel based on a microthermal device with impingement fluid jet and nanofluid as the working fluid. For this purpose, the numerical simulations of the nanofluid flow and heat transfer through the microchannel heat sink with impingement fluid jets is made. The laminar and stationary regime is considered. The water based Al2O3 nanofluid type is considered with various particle diameters and volume fractions of the particles. The results are presented in the form of the thermal resistance considered Reynolds number and fixed pumping power basis. It is concluded that cooling behavior of the micro-thermal device is strongly dependent both on the analysis basis and particle diameter or volume fractions. [ABSTRACT FROM AUTHOR]

In the present paper, a three-dimensional hydrogen absorption model is applied to a cylindrical LaNi5 hydride bed embedded with multiple U-shaped cooling channels having fins fitted in different orientations. Four number of cooling channels are placed radially at equal distances to achieve uniform heat removal from the bed. The fins are fixed to the coolant channel in transverse and radial directions. The fins volumetrically collect heat from the bed and deliver to the coolant channels. Three metal hydride bed cases are numerically studied, they are with: only coolant channels - case 1, coolant channels fitted with transverse fins - case 2 and coolant channels with transverse and radial fins - case 3. From the simulation results, it is revealed that the presence of fins in the coolant channels significantly improves the heat transfer and hydrogen absorption rate in the bed. The hydrogen absorption in the bed approaches 90% of saturation in 998 s, 867 s and 656 s for case 1, 2 and 3, respectively. Detailed multi-dimensional contours of temperature and hydrogen to metal ratio distributions in the bed are presented for different cases. This study provides a better understanding of heat and mass transfer during the hydrogen absorption in a metal hydride bed. [ABSTRACT FROM AUTHOR]

The contribution is the second step of the optimization process introduced on AMEE'13 where the position of cooling canal was searched. In this paper the outward shape of the regulation current body located in the axis of the system is optimized to obtain required temperature on the outward surface of the tube. The algorithm was designed and debugged for simplified model, in which the plunger is replaced by the tube, which is surrounded by thermal source representing cooled glass moulded piece from outward, and the cooling water of temperature 15°C on input flowing through. The state problem is formulated as a stationary heat conduction process. The cost functional is taken as the second power of L² distance of temperature from the given constant value on the outward boundary of the tube. The results of the numerical optimization to three required target temperatures 700, 750 and 800°C of the outward tube surface together with the distribution of temperatures on the interface between the tube and the heat source before and after the optimization process are presented. [ABSTRACT FROM AUTHOR]

Various methods of natural cooling are used to solve the problem of global warming and increase the energy efficiency of refrigeration systems. One of such methods is radiation cooling to outer space. In this paper we consider the possibility of using radiation cooling to lower the temperature of the liquid entering the processing once a day at 5:00. For cooling is proposed a system that is a cylindrical tank with a cooling casing. The coolant in the casing is cooled by the action of the radiators at night. The system is operated in the climatic conditions of the moderately cold climate of the Ust-Kamenogorsk city (Kazakhstan), located at 49°58'N. To assess the efficiency of the system, its mathematical modeling was carried out based on the solution of the heat balance equations. As a result of the simulation, data were obtained on the temperature and heat fluxes in the system during the year. It is found that the cooled liquid reaches the required temperature (<+ 5 °C) three hours after loading into the system for 123 days a year. The average daily specific cooling capacity of radiators reaches from 50 to 150 W/m² in winter and in the summer this value does not exceed 30 W/m². [ABSTRACT FROM AUTHOR]

The paper proposes a method of numerical study of heat exchange and temperature fields of self-lubricating cooled turbocharger bearing, the cooling system of which is implemented by the type of "water jacket" on the basis of ANSYS CFX package. To verify the heat exchange in the cooling channel of the bearing, an experimental stand was developed and tests were carried out. The results obtained by numerical and experimental methods have a good correspondence, which confirms the possibility of using the numerical method for solving engineering problems associated with the design of the cooling system of such a bearing. [ABSTRACT FROM AUTHOR]

Based on the results of experimental studies of the operating processes of the reciprocating compressor air long-stroke slow-speed stage under water and air cooling, verification of the calculation technique of this stage operating processes has been performed, which takes into account the influence of the intense cooling while pressure increasing from atmospheric to high discharge pressures in one stage. [ABSTRACT FROM AUTHOR]

The conducted theoretical analysis of the operating processes of the slow-speed long-stroke stage with variant cooling of various sections of the operating chamber allowed us to determine the rational range of cooled zones and the corresponding structural parameters of the cooling jacket, which allows to provide the permissible temperature of the pumped gas at minimum sizes and mass. [ABSTRACT FROM AUTHOR]

Relatively, R32 has very low GWP compared to R22, and therefore leading R32 to be a potential substitute for R22. This paper investigates the performance changes due to drop-in replacement of R22 to R32 in a residential air conditioner. The liquid density ratio between R32 and R22 at 0°C is 0.82. As a result, theoretically, for drop-in 100% from R22 with R32, the refrigerant charge amount of R32 is 82% of R22 (by mass). In this experiment, the refrigerant charge mass of R32 is varied from 90% to 105% with 5% increment for each measurement. Experimental results show that the optimal refrigerant charge amount is 95%. At this optimal refrigerant charge amount, the mass ratio of R32 to R22 is 77.9%. Meanwhile, at this mass ratio, the cooling capacity increased by 7.7% and COP decreased by 12.1%. [ABSTRACT FROM AUTHOR]