Browse Topic: Cooling
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The automotive sector is evolving both globally and as well as in India. The Indian customer’s expectations from an automobile are also evolving at fast pace. This is resulting in a continuous shrinkage of the time available for vehicle development. To meet customers’ expectation of superior cabin thermal comfort it is important to predict cabin cooling performance at early stage. This can be achieved through thermal simulation. Existing studies of cabin thermal simulation explained the method of co-simulation. Wherein, Input for the cabin was used a grill air temperature which was obtained from the physical test. It showed good correlation for the cabin inside air temperature with actual test. However, cabin cooling performance does not only depend on cabin structure & layout but also, affected by AC system & its component level performance. AC systems and components were not considered in previous studies. As a result, replacing or modifying the AC system components does not allow us
A typical modern automobile compressor-driven air conditioner, about powerful enough to cool a house, may not be needed even in very hot, humid climates if we combine insights from comfort theory with innovations in comfort delivery, photonics, and superefficient thermal and air-handling devices. Recent advances can successively minimize unwanted heat gain into the passenger cabin, cool people’s bodies rather than the vehicle, deliver highly effective radiant cooling, passively reject extracted heat to the sky, and, if needed, move air very efficiently and quietly to expand the human comfort range. Together these proven innovations may give automotive occupants excellent hot-weather comfort without refrigerative air conditioning. This substitution could improve climate protection and electric-vehicle range, cut the automobile’s weight and cost, avoid climate and ozone harm from refrigerants, reduce noise and air pollution, make autos more energy-efficient, and save the United States
Battery thermal management for electric vehicles have gained significance over recent years, especially for the present lithium-ion batteries. However, high operating temperature and uneven temperature distribution inside the battery cell can significantly reduce capacity and lifetime. The temperature difference between the battery cells needs to be minimized to avoid premature aging of specific cells exposed to a higher temperature. The most common way to dissipate heat from the battery cells is to use air or liquid cooling. Air cooling is less complex than liquid cooling, but the extremely high ambient temperature dramatically limits the usage of air cooling. This paper developed a thermal connector that could be repeatedly assembled and disassembled between the battery cell. The thermal connector can effectively dissipate the heat into the refrigeration cycle while providing constant thermal resistance among the battery cells, which can be as lower as 0.115°C/W. Heat transfer
Camels keep cool while conserving water in a scorching desert environment via a thick coat of insulating fur. Applying essentially the same approach, researchers have developed a system that could help keep things like pharmaceuticals or fresh produce cool in hot environments without the need for a power supply
A systematic and comprehensive first law analysis of a cooled gas turbine cycle subjected to vapor compressor inlet air cooling (VC-IAC) has been conducted in our study. Film air cooling technique has been implemented to cool the gas turbine (GT) buckets. The gas turbine is subjected to variation of various operating and ambient parameters and the corresponding effect is analyzed to find out the optimal one. The integration of VC-IAC has been reported to further enhance the plant specific work and plant efficiency of gas turbine cycle, the enhancement being higher in regions having a hot and dry climate. This increase in cycle performance due to VC-IAC has been found superior in case of bucket cooled GT cycle when compared to uncooled one. It has further been witnessed that the plant specific work increases by more than 0.35 % and the plant efficiency increases by little above 0.1 % for every 1o C drop in CIT. The work ratio representing the excess of work of turbine over work of
Effective cooling of a heated brake system is critical for vehicle safety and reliability. While some flow devices can redirect airflow more favorably for convective cooling, such a change typically accompanies side effects, such as increased aerodynamic drag and inferior control of brake dust particles. The former is critical for fuel efficiency while the latter for vehicle’s soiling and corrosion as well as non-exhaust emissions. These competing objectives are assessed in this study based on the numerical simulations of an installed brake system under driving conditions. The thermal behavior of the brake system as well as aerodynamic impact and brake dust particle deposition on areas of interest are solved using a coupled 3D transient flow solver, PowerFLOW. Typical design considerations related to enhanced brake cooling, such as cooling duct, wheel deflector, and brake air deflector, are characterized to evaluate the thermal, aerodynamic and soiling performance targets. The leading
Overheating of the brake disc is a major concern in the brake performance. Overheating is the main cause of a reduction in braking efficiency, especially if a vehicle is fully loaded. The heat dissipation rate for Solid rotors is very low. In order to increase the heat dissipation rate, the disc must be used with ventilation provided on it. Further in ventilated disc rotors, the ribs in between the rotors provide cooling. The ribs allow the flow of heat and pull out the air in between the rotors for efficient cooling. In this research, four different brake disc namely, Solid Disc (SL), Cross-drilled disc (CD), Cross-slot disc (CS) and Hybrid disc (CD-CS-SG) which is a combination of Cross drilled and slot with side groove have been analyzed at various brake conditions in the form of heat generation and thermal stresses. The temperature gradient over the surface is studied using the thermal numerical simulations and the stress generated within the structure core of hybrid rotor is
Common cooling methods such as air conditioners are expensive, consume significant amounts of energy, require ready access to electricity, and often require coolants that deplete ozone or have a strong greenhouse effect. An alternative to these energy-intensive cooling methods is passive daytime radiative cooling (PDRC), a phenomenon where a surface spontaneously cools by reflecting sunlight and radiating heat to the colder atmosphere. PDRC is most effective if a surface has a high solar reflectance that minimizes solar heat gain and a high thermal emittance that maximizes radiative heat loss to the sky
A tested method of data presentation and use is described herein. The method shown is a useful guide, to be used with care and to be improved with use
With the exception of thermal storage heat sinks, the term heat sink is a misnomer. Standard heat sinks for electronics cooling are actually heat exchangers, taking the heat from the electronics, and transferring it to a fluid, either air or coolant. Phase Change Material (PCM) heat sinks are the only heat sinks that actually act as a (temporary) sink for heat. They are emerging in the thermal management realm to solve thermal problems in systems where active solutions cannot be used. When there is no place to dissipate the heat generated by electric components, a PCM heat sink is capable of absorbing the generated waste heat [1
Professor Hopkins and University of Virginia colleagues — in collaboration with materials scientists at Penn State, the University of Maryland, and the National Institute of Standards and Technology — have studied a material that can dynamically regulate its thermal properties, switching back and forth between insulating and cooling based on the amount of water that is present
The integration of inlet air cooling to gas turbine based power utilities is a well accepted practice as this modification to the utility delivers superior utility performance. However, application of inlet-air cooling to drive turbines and specifically to marine mobility sector is rare in literature. Marine vessels are generally propelled by diesel engines, however large marine vessels specifically cruise ships and high speed naval vessels may have requirements of higher speeds and on-board power requirements which can fulfilled by gas turbine driving the propellers while on-board power needs can be met by steam turbine power generated from gas turbine exhaust heat. Such gas-steam combined cycles have the potential to become popular for high capacity marine vessels. The choice of gas turbine based combined cycle power plant for marine vessels in comparison to diesel engine powered vessel is also superior due to lower emission from the former. Higher ambient temperatures are known to
In today’s automotive industry, the A/C (Air-conditioning) system is emerging into a high level of technological growth to provide quick cooling, warm up and maintaining the air quality of the cabin during all-weather conditions. In HVAC system, TXV plays vital role by separating high side to low side of vapor compression refrigeration system. It also regulates the amount of refrigerant flow to the evaporator based on A/C system load. The HVAC system bench laboratory conducts the test at different system load conditions to evaluate the outputs from tests during initial development stage to select the right TXV in terms of capacity and Superheat set point for a given system. This process is critical in HVAC developmental activity, since mule cars will be equipped with selected TXV for initial assessment of the system performance. The TXV tuning is conducted in system bench lab using defined test load cases which is developed using combination of given input boundary conditions and tests
This paper provides a review on state-of-art modern cooling systems employed for thermal cooling of electric motors for vehicle applications. In recent years, the pursue of a more sustainable and ecofriendly mobility has pushed the research towards the development of electric vehicle powertrain systems. Besides the evident advantages of the adoption of electric traction systems in terms of pollution and efficiency, the need of an effective cooling system for the electric machine components gained more and more importance in order to maintain high efficiency and ensure high durability. In fact, it is known that high temperatures can be harmful for the electric motor: besides the evident damages for mechanical parts, the influence on the permanent magnet properties is not negligible [1] [2]. In this fast-evolving environment, different solutions for the thermal problem have been researched and adopted, each one with its own pros and cons. Those who face the development of a PM machine
Hyundai's new engine is developed which optimize the cooling efficiency for knocking improvement and friction reduction. The cooling concepts for this purpose are 1) equalizing the temperature among cylinders by flow optimization, 2) cooling the required area intensively, 3) adopting ‘active flow control’ and 4) enlarging fuel economy at high speed range. In order to realize the cooling concept, 1) cross-flow, 2) compact water jacket & exhaust cooling, 3) flow control valve and 4) cylinder head with integrated exhaust manifold are considered. Improvement of knocking and friction reduction by increased cooling water temperature makes fuel efficiency possible. On the other hand, in order to strengthen the cooling around the combustion chamber and to reduce the deviation among the combustion chamber of cylinders, it is required to design the head water jacket shape accordingly. It is a very important task to decide the appropriate cooling water capacity in water jacket and to secure the
(These definitions were prepared by the Joint Committee on Definitions of Terms Relating to Heat Treatment appointed by the American Society for Testing and Materials, The American Society for Metals, the American Foundrymen's Association, and the SAE.) This SAE revision emphasizes the terms used in heat treating ferrous alloys, but also includes for reference some non-ferrous definitions at the end of the document. This glossary is not intended to be a specification, and it should not be interpreted as such. Since this is intended to be strictly a set of definitions, temperatures have been omitted purposely
This standard covers the requirements for spherical, self-aligning, self-lubricating bearings which are for use in the ambient temperature range -65 to +160 °F (-54 to +71 °C) at high cyclic speeds. The scope of the standard is to provide a liner system qualification procedure for helicopter sliding bearings defined and controlled by source control drawings. Once a liner system is qualified the source-controlled bearings are further tested under application conditions
This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, flash welded rings, and stock for forging or flash welded rings
As one of the most crucial components in electric vehicles, power batteries generate abundant heat during charging and discharging processes. Thermal management system (TMS), which is designed to keep the battery cells within an optimum temperature range and to maintain an even temperature distribution from cell to cell, is vital for the high efficiency, long calendar life and reliable safety of these power batteries. With the desirable features of low system complexity, light weight, high energy efficiency and good battery thermal uniformity, thermal management using composite phase change materials (PCMs) has drawn great attention in the past fifteen years. In the hope of supplying helpful guidelines for the design of the PCM-based TMSs, this work begins with the summarization of the most commonly applied heat transfer enhancement methods (i.e., the use of thermally conductive particles, metal fin, expanded graphite matrix and metal foam) for PCMs by different researchers. Newly
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