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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]

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]

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]

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]

In this paper, the sinter cooling process is numerically studied to get the pressure field, velocity field and temperature field when the fluid flows through the porous media by developing a two-dimensional unsteady state computational model. The inlet velocity, layer height, porosity and sinter layer distribution are the main parameters affecting the sinter cooling process. The computational fluid dynamics (CFD) technique is employed to investigate the influences of thermal process of the four parameters. When high temperature sinters are loaded into the sinter cooler from the sintering machine, phenomena of the non-uniform distribution of sinter size takes place which always causes the non-uniform distribution of sinter temperature field and leads to the deformation of the conveyors. In order to get a uniform sinter temperature field, several recommendations are proposed. The results discussed in this paper would be important for the further understanding of the thermal process and transformation of the sinter cooler. [ABSTRACT FROM AUTHOR]

A study of spectral evolutions of gamma-ray burst (GRB) prompt emissions observed with Suzaku Wide-band All-sky Monitor (WAM) is presented. Thank to the large effective areas, Suzaku-WAM is one of the best instruments to investigate spectral evolutions of the GRB prompt emissions. In general the rise and decay time scales in the light curves are determined by the heating and cooling time scale and geometrical effect of the emission regions. It has been argued that the expected highly relativistic emission regions and its deceleration would produce spectral evolution could cause apparent spectral evolution in the observer frame. However, it is not easy to attribute exponential decays with spectral evolutions to the relativistic effect of the GRB jet. In other words, electron cooling is the key to solve the spectral variations in the exponential decays. This paper focuses the isolated fast-rise-exponential-decay (FRED) type light curve observed with WAM and their spectral evolutions, and revealed an energy dependence of the time constant of the observed exponential decay. The 'energy indices' observed from some of the GRBs are consistent with those expected in synchrotron or inverse Compton cooling. [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]

One challenge in the extrusion process of thick-walled pipes is the cooling of the product. Besides the output of the extruder, the line speed is also limited by the efficiency of the cooling line. The cooling time increases according to the wall thickness of the pipe under otherwise equal process conditions. State of the art is the cooling of the outer surface in water tanks or spray-cooltanks. In addition to that, it is possible to cool the inner surface by air that is sucked through the pipe. Despite these technologies it is problematic to cool down thick walled-products with the right speed. Especially thick-walled pipes show problems by cooling the layers in the middle of the wall. On the one hand an intensive cooling of the outer and inner surface of the pipe entail the formation of shrink holes in the middle of the pipe wall. On the other hand without a quick cooling the melt flow in circumferential direction because of the gravity takes place (sagging-effect). Because of this reason in the presented paper new possibilities of melt cooling in extrusion dies to prevent sagging-effects are given. An aimed cooling of the inbound melt layers inside the extrusion die could prevent the effect of melt flow in circumferential direction after the extrusion die, allows the specification of a specific temperature profile over the radius of the pipe wall and helps to reduce the melt temperature for rising mass throughputs and screw driving speeds of the extruder. It is also thinkable to influence the crystallization process and thereby the mechanical properties of the end-product by an aimed cooling of the inner pipe layers. [ABSTRACT FROM AUTHOR]

The Coherent electron Cooling (CeC) Proof of Principle (PoP) experiment is proposed to be installed in the Relativistic Heavy Ion Collider (RHIC) to demonstrate proton and ion beam cooling with this new technique that may increase the beam luminosity in certain cases, by as much as tenfold. Within the scope of this project, a 112 MHz, 2MeV Superconducting Radio Frequency (SRF) electron gun and a 704 MHz 20MeV 5-cell SRF cavity will be installed at IP2 in the RHIC ring. The superconducting RF electron gun will be cooled in a liquid helium bath at 4.4 K. The 704 MHz 5- cell SRF cavity will be cooled in a super-fluid helium bath at 2.0 K. This paper discusses the cryogenic systems designed for both cavities. For the 112 MHz cavity cryogenic system, a condenser/boiler heat exchanger is used to isolate the cavity helium bath from pressure pulses and microphonics noise sources. For the 704 MHz 5-cell SRF cavity, a heat exchanger is also used to isolate the SRF cavity helium bath from noise sources in the sub-atmospheric pumping system operating at room temperature. Detailed designs, thermal analyses and discussions for both systems will be presented in this paper. [ABSTRACT FROM AUTHOR]

In a 4K Gifford-McMahon (GM) cryocooler, the performance of the second stage is strongly dependent on the efficiency of the second stage regenerator. In order to improve the efficiency of the second stage regenerator, the internal dynamic parameters are analyzed by numerical simulation. It is found that the performance of a 4K GM cryocooler can be improved by shifting the temperature profile in the second stage regenerator to a higher level. The temperature profile in the second stage regenerator with an artificially reduced heat capacity of the regenerator material at the warm end is analyzed. Based on the simulation results, a novel and simple way, which is to replace the regenerator material at the warm end with a material having a lower heat capacity, is proposed. By reducing the heat capacity to 20 % of lead, the PV power is increased by 7.9 W at the first stage and 1.8 W at the second stage. Correspondingly, the cooling capacity is increased by 9.0 W at the first stage and 0.13 W at the second stage. However, if the heat capacity is further reduced to 10 % of lead, the effect is reduced. The P-V power is increased by only 1.9 W at the first stage and 0.1 W at the second stage. The enthalpy flux from the regenerator is increased by 0.7 W at the first stage and 0.1 W at the second stage. Accordingly, the cooling capacity is increased by only 2.2 W at the first stage and 0.01 W at the second stage. The simulation results will be reported in this paper. [ABSTRACT FROM AUTHOR]

The 4K stage is a critical step for space missions. The Hershel mission is using a helium bath, which is consumed day by day (after depletion, the space mission is over) while the Plank mission is equipped with one He4 Joule-Thomson cooler. Cryogenic chain without helium bath is a challenge for space missions and 4.2K Pulse-Tube working at high frequency (around 30Hz) is one option to take it up. A low temperature Pulse-Tube would be suitable for the ESA space mission EChO (Exoplanet Characterisation Observatory, expected launch in 2022), which requires around 30mW cooling power at 6K; and for the ESA space mission ATHENA (Advanced Telescope for High ENergy Astrophysics), to pre-cool the sub-kelvin cooler (few hundreds of mW at 15K). The test bench described in this paper combines a Gifford-McMahon with a coaxial Pulse- Tube. A thermal link is joining the intercept of the Pulse-Tube and the second stage of the Gifford-McMahon. This intercept is a separator between the hot and the cold regenerators of the Pulse-Tube. The work has been focused on the cold part of this cold finger. Coupled with an active phase shifter, this Pulse-Tube has been tested and optimized and temperatures as low as 6K have been obtained at 30Hz with an intercept temperature at 20K. [ABSTRACT FROM AUTHOR]

The compressor system used for the Jefferson Lab (JLab) 12 GeV upgrade, also known as the CHL-2 compressor system, incorporates many design changes to the typical compressor skid design to improve the efficiency, reliability and maintainability from previous systems. These include a considerably smaller bulk oil separator design that does not use coalescing elements/media, automated control of cooling oil injection based on the helium discharge temperature, a helium after-cooler design that is designed for and promotes coalescing of residual oil and a variable speed bearing oil pump to reduce oil bypass. The CHL-2 helium compression system has five compressors configured with four pressure levels that supports the three pressure levels in the cold box. This paper will briefly review several of these improvements and discuss some of the recent commissioning results. [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]

Closed-cycle Joule-Thomson (JT) cryocoolers have been developed at National Metrology Institute of Japan (NMIJ)/National Institute of Advanced Industrial Science and Technology (AIST) with the aim of realizing a liquid-helium-free calibration apparatus for cryogenic thermometers between 0.65 K and 25 K. The latest JT cryocooler at NMIJ/AIST consists of a 3He JT cooling circuit and a pulse tube mechanical refrigerator. The characteristics of the apparatus including a residual gas analysis of the JT cooling circuit are presented in this paper. Currently the initial cool-down is performed using a heat-exchange gas. It normally takes about 30 h to reduce the temperature from room temperature to 5 K at the thermometer comparison block of the apparatus. The correct timing of the removal of the heatexchange gas is important for the efficient operation of the apparatus. Incomplete removal of the heat-exchange gas induces excess heat load on the apparatus and thermal disturbances. Some examples of abrupt temperature bursts are discussed in this paper. Mechanical refrigerators generate cyclic mechanical vibrations, and precision resistance thermometers are usually very sensitive to a mechanical vibration. The measured vibration level of the developed apparatus is reported. The damage to the apparatus due to the magnitude 9.0 earthquake on March 11, 2011, and possible countermeasures in the case of future earthquakes are also discussed. [ABSTRACT FROM AUTHOR]

This paper documents the 3D modeling and simulation of a three couple thermoelectric module using the Synopsys Technology Computer Aided Design (TCAD) semiconductor simulation software. Simulation results are presented for thermoelectric power generation, cooling and heating, and successfully demonstrate the basic thermoelectric principles. The 3D TCAD simulation model of a three couple thermoelectric module can be used in the future to evaluate different thermoelectric materials, device structures, and improve the efficiency and performance of thermoelectric modules. [ABSTRACT FROM AUTHOR]

High Temperature Superconducting (HTS) cable systems have many advantages such as high transmission efficiency, high capacity, and low over conventional cables. On the other hand, the reliability and economic efficiency of the HTS cable system has not been verified; therefore, there are not many precedent studies for applying HTS cables on commercial power grids, Korea Electric Power Corporation (KEPCO) has started a project of operating and manufacturing technology for applying 22.9 kV, 50 MVA, and 500 m class HTs cable to the commercial power grid in 2008. LS cable Ltd. has joined this project for designing and manufacturing HTS power cable including the colling system. We have verified the reliability and economic efficiency of the system throughout this real power grid connection project. In this paper, we introduce the design of the colling sytem for the 500 m class HTS cable and summarize the results of its performance testing. [ABSTRACT FROM AUTHOR]

Applications in superconductivity have become widespread, enabled by advancements in cryogenic engineering. In this paper, the history of cryogenic refrigeration, its delivery, its preservation and the important scientific and engineering advancements in these areas in the last 100 years will be reviewed, beginning with small laboratory dewars to very large scale systems. The key technological advancements in these areas that enabled the development of superconducting applications at temperatures from 4 to 77 K are identified. Included are advancements in the components used up to the present state-of-the-art in refrigeration systems design. Viewpoints as both an equipment supplier and the end-user with regard to the equipment design and operations will be presented. Some of the present and future challenges in these areas will be outlined. Most of the materials in this paper are a collection of the historical materials applicable to these areas of interest. [ABSTRACT FROM AUTHOR]

Ball Aerospace and Redstone Aerospace are developing a space cryocooler for cooling complex optical systems whose loads are intermittent. An example of such a system would be an Earth observation satellite that images for only a fraction of its orbit. If a cooler can store refrigeration during the lull and provide it when the system is active, the cooler can be considerably smaller than one sized to provide the full load continuously. Our cooler provides two stages of refrigeration, a stage of intermittent cooling at 35 K for a focal plane assembly and a stage of continuous cooling at 85 K for the surrounding thermal shields. The cooler provides the intermittent cooling by collecting liquid neon in a unique internal thermal storage tank and forwarding it to the focal plane when the heat loads are high. Our paper presents extensive performance data for neon at 35 K. It carries 2 W at 35 K for 30 minutes plus the 8.5 W of continuous cooling at 85 K for less than 300 W DC power. It is ready to cool again in an hour. For contrast, the same hardware was filled with nitrogen and tested at 82 K. It carries 5 W for 25 minutes plus 15 W of continuous cooling at 130 K for less than 220 W DC power. It is ready to cool again in a little over an hour. The system has many features for space system compatibility. Because the storage is located within an active control loop, the cooler can maintain the 35 K interface temperature to better than ± 0.1 K. Because it circulates liquid it can be located remotely, which solves many compatibility issues. And with careful liquid management, it can work in any orientation and in 0-g. In this paper our flight like equipment will be described, and its continuing evolution to flight will be discussed. [ABSTRACT FROM AUTHOR]

Sorption-based Joule-Thomson coolers operate vibration-free, have a potentially long life time, and cause no electromagnetic interference. Therefore, they are appealing to a wide variety of applications, such as cooling of low-noise amplifiers, superconducting electronics, and optical detectors. The required cooling temperature depends on the device to be cooled and extends into the cryogenic range well below 80 K. This paper presents the optimization of the working fluid for sorption-based JT coolers. For specific combination of the cold and warm-end temperatures, the working fluid is optimized based on the overall coefficient of performance that is defined as the heat rejected to the cold tip (i.e. the cooling energy) per unit of the heat supplied to the sorption compressor. In this study, saran carbon is considered as the sorbent material. [ABSTRACT FROM AUTHOR]

In this paper, copper and aluminum foams with different porosity, number of pores per inch (PPI) and foam core height, are experimentally studied during air forced convection. The experimental measurements permit to understand how each parameter (i.e. porosity, PPI, material, and foam thickness) affects the heat transfer and fluid flow behavior of the metal foams. The paper presents the experimental heat transfer coefficients, permeability and inertia coefficients; moreover, it reports the normalized mean wall temperature as a function of the pumping power per unit of heat transfer area: two meaningful parameters that allow quantitative comparisons of different enhanced surfaces, which can be considered suitable for electronic thermal management. [ABSTRACT FROM AUTHOR]

In a recent paper [A. Santos, G. M. Kremer, and V. Garzó, Prog. Theor. Phys. Suppl. 184, 31-48 (2010)] the collisional energy production rates associated with the translational and rotational granular temperatures in a granular fluid mixture of inelastic rough hard spheres have been derived. In the present paper the energy production rates are explicitly decomposed into equipartition rates (tending to make all the temperatures equal) plus genuine cooling rates (reflecting the collisional dissipation of energy). Next the homogeneous free cooling state of a binary mixture is analyzed, with special emphasis on the quasi-smooth limit. A previously reported singular behavior (according to which a vanishingly small amount of roughness has a finite effect, with respect to the perfectly smooth case, on the asymptotic long-time translational/translational temperature ratio) is further elaborated. Moreover, the study of the time evolution of the temperature ratios shows that this dramatic influence of roughness already appears in the transient regime for times comparable to the relaxation time of perfectly smooth spheres. [ABSTRACT FROM AUTHOR]

Parametric-resonance Ionization Cooling (PIC) [1-3] is envisioned as the final 6D cooling stage of a high-luminosity muon collider. Implementing PIC imposes stringent constraints on the cooling channel's magnetic optics design. This paper presents a linear optics solution compatible with PIC. Our solution consists of a superposition of two opposite-helicity equal-period and equal-strength helical dipole harmonics and a straight normal quadrupole. We demonstrate that such a system can be adjusted to meet all of the PIC linear optics requirements while retaining large acceptance. [ABSTRACT FROM AUTHOR]

This paper presents experimental and Computational Fluids Dynamics (CFD) investigations of the flow in ventilated brake discs. Development of an experiment rig with basic measuring devices are detailed out and following a validation study, the possible improvement in the brake cooling can be further analyzed using CFD analysis. The mass flow rate is determined from basic flow measurement technique following that the conventional bi-directional passenger car is simulated using commercial CFD software FLUENT™. The CFD simulation is used to investigate the flow characteristics in between blade flow of the bi-directional ventilated disc brake. [ABSTRACT FROM AUTHOR]

Dewar pressure build-up coils, thermosiphon cooling systems and closed loop thermosiphons are simple and effective tools when properly designed and fabricated. However, out of ignorance or misplaced economy, some of these systems work poorly or not at all. This paper reviews the fundamentals of gravity systems and addresses the details of designing each of the three subject applications. [ABSTRACT FROM AUTHOR]

Muon ionization cooling R&D is important for a neutrino factory and future muon collider. In addition to theoretical studies, much progress has been made in muon cooling channel hardware R&D since NuFact-2006. This paper reports the progress on hardware R&D that includes experimental RF test programs using 805-MHz RF cavity, superconducting (SC) solenoids (coupling coils), 201-MHz RF cavity, liquid hydrogen absorber and MUCOOL Test Area (MTA) experiment preparation for beam tests. [ABSTRACT FROM AUTHOR]

The Fermilab Electron Cooling Project requires a straight trajectory and constant beam size to provide maximum cooling of the antiprotons in the Recycler. A measurement system was developed using movable apertures and steering bumps to measure the beam size in a 20m long, nearly continuous, solenoid. This paper will focus on results of these measurements of the beam size and the difficulties in making those measurements. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

This paper discusses the development of an advanced hybrid loop technology that incorporates elements from both passive and active loop technologies. The result is a simple yet high performance cooling technology that can be used to remove high heat fluxes from large heat input areas. Operating principles and test results of prototype hybrid loops are discussed. Prototype hybrid loops have been demonstrated to remove heat fluxes in excess of 350W/cm2 from heat input areas over 4cm2 with evaporator thermal resistances between 0.008 and 0.065°C/W/cm2. Also importantly, this performance was achieved without the need to actively adjust or control the flows in the loops, even when the heat inputs varied between 0 and 350W/cm2. These performance characteristics represent substantial improvements over state of the art heat pipes, loop heat pipes and spray cooling devices. The hybrid loop technology was demonstrated to operate effectively at all orientations. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]