scholarly journals Improving the cooling systems of automotive engines and methods for monitoring their condition

2021 ◽  
pp. 41-44
Author(s):  
E.P. Parlyuk ◽  
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Heat Dissipation ◽  
Cooling System ◽  
Quantitative Relationship ◽  
Thermal Processes ◽  
Structural Diagram ◽  
Cooling Systems ◽  
Automotive Engines ◽  
Machine Operation

It has been established that the cooling system of modern tractors and trucks can include 5 to 7 independent cooling circuits. A structural diagram of a modular cooling system for automotive engines and a mathematical model of thermal processes in a heat exchanger of the modular cooling system during machine operation are proposed. It is shown that the development of an algorithm for predicting and monitoring the state of the modular cooling system is possible based on a quantitative relationship between the rate of decrease in heat dissipation capacity and the duration of machine operation.

Remote Heat Pipe Based Heat Exchanger Performance in Notebook Cooling

2005 ◽  
Author(s):  
Seyyed Khandani ◽  
Himanshu Pokharna ◽  
Sridhar Machiroutu ◽  
Eric DiStefano
Keyword(s):  
Heat Exchanger ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Cooling System ◽  
Temperature Drop ◽  
Operating Conditions ◽  
Cooling Systems ◽  
Temperature Variations ◽  
Non Linear ◽  
Condenser Temperature

Remote heat pipe based heat exchanger cooling systems are becoming increasingly popular in cooling of notebook computers. In such cooling systems, one or more heat pipes transfer the heat from the more populated area to a location with sufficient space allowing the use of a heat exchanger for removal of the heat from the system. In analsysis of such systems, the temperature drop in the condenser section of the heat pipe is assumed negligible due to the nature of the condensation process. However, in testing of various systems, non linear longitudinal temperature drops in the heat pipe in the range of 2 to 15 °C, for different processor power and heat exchanger airflow, have been measured. Such temperature drops could cause higher condenser thermal resistance and result in lower overall heat exchanger performance. In fact the application of the conventional method of estimating the thermal performance, which does not consider such a nonlinear temperature variations, results in inaccurate design of the cooling system and requires unnecessarily higher safety factors to compensate for this inaccuracy. To address the problem, this paper offers a new analytical approach for modeling the heat pipe based heat exchanger performance under various operating conditions. The method can be used with any arbitrary condenser temperature variations. The results of the model show significant increase in heat exchanger thermal resistance when considering a non linear condenser temperature drop. The experimental data also verifies the result of the model with sufficient accuracy and therefore validates the application of this model in estimating the performance of these systems.   This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.

scholarly journals Mathematical model of thermal processes in a biogas plant

2018 ◽  
Vol 212 ◽  
pp. 01032 ◽  
Author(s):  
Amur Fiapshev ◽  
Olesya Kilchukova ◽  
Yuriy Shekikhachev ◽  
Marat Khamokov ◽  
Luan Khazhmetov
Keyword(s):  
Mathematical Model ◽  
Heat Exchanger ◽  
Biogas Plant ◽  
Thermal Processes ◽  
Livestock Waste ◽  
Technological Parameters ◽  
Entire Volume ◽  
Design Characteristics ◽  
Alternative Sources ◽  
The Given

One of the promising areas of processing poultry and livestock waste is anaerobic digestion, which helps to prevent pollution of the natural environment, as well as to receive processing products such as gaseous fuel, biogas and highly effective biofertilizer. The use of plants for the production of biological gas as alternative sources of energy is largely determined by its design characteristics and the worked out technological regimes. The study was conducted with the aim of obtaining data on the effect of the main parameters of the biogas plant and the heat exchanger-agitator on the quality of its operation. This paper considers the thermal processes taking place in the biogas plant in which the mixing device and the heating element are combined into one unit, which allows heating and maintaining the given temperature regime more evenly due to the rotation of the heat exchanger and the transfer of biomass heat throughout the whole volume of the methane. As a result of theoretical studies of the processes of heat exchange and heat transfer taking place in the biogas plant, a mathematical model has been obtained that allows determining the distribution of the temperature of the biomass throughout the entire volume of the methane. It is established that the theoretical temperature homogeneity of the stirred medium is achieved by combining the heat exchanger and the mixing device into one unit, the design and technological parameters of which characterize the intensity of the forced motion of fermentable manure, while changing the value of thermal conductivity.

Review and Projections of Integrated Cooling Systems for Three-Dimensional Integrated Circuits

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Satish G. Kandlikar
Keyword(s):  
Hot Spots ◽  
Heat Dissipation ◽  
Cooling System ◽  
Mechanical Design ◽  
Heat Fluxes ◽  
Electrical Performance ◽  
Channel Height ◽  
Cooling Systems ◽  
3D Ic ◽  
Pressure Drops

In an effort to increase processor speeds, 3D IC architecture is being aggressively pursued by researchers and chip manufacturers. This architecture allows extremely high level of integration with enhanced electrical performance and expanded functionality, and facilitates realization of VLSI and ULSI technologies. However, utilizing the third dimension to provide additional device layers poses thermal challenges due to the increased heat dissipation and complex electrical interconnects among different layers. The conflicting needs of the cooling system requiring larger flow passage dimensions to limit the pressure drop, and the IC architecture necessitating short interconnect distances to reduce signal latency warrant paradigm shifts in both of their design approach. Additional considerations include the effects due to temperature nonuniformity, localized hot spots, complex fluidic connections, and mechanical design. This paper reviews the advances in 3D IC cooling in the last decade and provides a vision for codesigning 3D IC architecture and integrated cooling systems. For heat fluxes of 50–100 W/cm2 on each side of a chip in a 3D IC package, the current single-phase cooling technology is projected to provide adequate cooling, albeit with high pressure drops. For future applications with coolant surface heat fluxes from 100 to 500 W/cm2, significant changes need to be made in both electrical and cooling technologies through a new level of codesign. Effectively mitigating the high temperatures surrounding local hot spots remains a challenging issue. The codesign approach with circuit, software and thermal designers working together is seen as essential. The through silicon vias (TSVs) in the current designs place a stringent limit on the channel height in the cooling layer. It is projected that integration of wireless network on chip architecture could alleviate these height restrictions since the data bandwidth is independent of the communication lengths. Microchannels that are 200 μm or larger in depth are expected to allow dissipation of large heat fluxes with significantly lower pressure drops.

Experimental Study of Heat Pipe Exchanger for High Power LED Cooling System

2011 ◽  
Vol 295-297 ◽  
pp. 1985-1988
Author(s):  
Yu Jun Gou ◽  
Zhong Liang Liu ◽  
Xiao Hui Zhong
Keyword(s):  
Heat Exchanger ◽  
Heat Pipe ◽  
High Power ◽  
Heat Dissipation ◽  
High Efficiency ◽  
Cooling System ◽  
Two Phase ◽  
High Power Led ◽  
New Type ◽  
Two Phase Heat Transfer

A new cooling concept for high power LED by combining the heat release of high power LED with two-phase heat transfer heat pipes was proposed, and in this study a new type of heat pipe with specific fins structure was developed. Through experimental results, we found the new heat pipe heat exchanger has the features of high efficiency of heat dissipation and compact construction which meets the demand of heat dissipation for high power LED. We also found the heat dissipation performance of the HP heat exchanger changed with the work angle.

Thermal Performance of Domestic Replacement A19 LED Lighting Products

2016 ◽  
Author(s):  
Thomas Storey ◽  
Robin Rackerby ◽  
Heather Dillon ◽  
Lydia Gingerich
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Heat Dissipation ◽  
Cooling System ◽  
Light Emitting Diode ◽  
Research Process ◽  
Light Emitting ◽  
Led Lighting ◽  
Proper Design ◽  
The Cost

In an effort to create a Light Emitting Diode (LED) lighting system that is as efficient as possible, the heat dissipation system must be accurately measured for proper design and operation. Because LED lighting technology is new, little optimization has been performed on typical cooling system required for most A19 replacement products. This paper describes the research process for evaluating the thermal performance of over 15 LED lighting products and compares their performance to traditional lighting sources, namely incandescent and compact fluorescent (CFL). This process uses radiation and convection to model typical cooling mechanisms for domestic A19 type replacement LED products. The A19 products selected for this investigation had input wattages ranging between 7 to 60 Watts, with outputs ranging from 450 to 1100 lumens. The average LED tested dissipated 43% (± 5%) of the total heat generated in the lighting product through the heat exchanger. The best thermal performance was observed in an LED product that dissipated approximately 58% of the total product heat through the heat exchanger. Results indicate that significant improvements to the current LED heat exchanger designs are possible, which will help lower the cost of future LED products, improve performance, and reduce the environmental footprint of the products.

Mathematical Model for Spray Cooling Systems

1977 ◽  
Vol 99 (2) ◽  
pp. 279-283 ◽  
Author(s):  
H. A. Frediani ◽  
N. Smith
Keyword(s):  
Mathematical Model ◽  
Large Scale ◽  
Cooling System ◽  
Spray Cooling ◽  
System Model ◽  
Cellular Model ◽  
Cooling Systems ◽  
Cellular Analysis ◽  
Finite Difference Solution ◽  
Energy Equations

A mathematical model of a large-scale spray cooling system is described. The continuity and energy equations are developed for a cellular model representing a single spray in a system of sprays. The equations are solved using a finite-difference solution along a drop trajectory for both water and air parameters. The results of the cellular analysis are incorporated into a system model in which the interaction between sprays for both the water and air is considered. The model was used to simulate existing systems employing multiple rows of sprays, and the results of the calculations compare well with the available data.

Liquid Cooling Network Systems for Energy Conservation in Data Centers

2011 ◽  
Author(s):  
Mayumi Ouchi ◽  
Yoshiyuki Abe ◽  
Masato Fukagaya ◽  
Haruhiko Ohta ◽  
Yasuhisa Shinmoto ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Data Center ◽  
Single Phase ◽  
Cooling System ◽  
Heat Pipes ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Two Phase ◽  
Cooling Systems ◽  
Cooling Methods

Energy consumption in data center has been drastically increasing in recent years. In data center, server racks are cooled down by air conditioning for the whole room in a roundabout way. This air cooling method is inefficient in cooling and it causes hotspot problem that IT equipments are not cooled down enough, but the room is overcooled. On the other hand, countermeasure against the heat of the IT equipments is also one of the big issues. We therefore proposed new liquid cooling systems which IT equipments themselves are cooled down and exhaust heat is not radiated into the server room. For our liquid cooling systems, three kinds of cooling methods have been developed simultaneously. Two of them are direct cooling methods that the cooling jacket is directly attached to heat source, or CPU in this case. Single-phase heat exchanger or two-phase heat exchanger is used as cooling jackets. The other is indirect cooling methods that the heat generated from CPU is transported to the outside of the chassis through flat heat pipes, and condensation sections of the heat pipes are cooled down by liquid. Verification tests have been conducted by use of real server racks equipped with these cooling techniques while pushing ahead with five R&D subjects which constitute our liquid cooling system, which single-phase heat exchanger, two-phase heat exchanger, high performance flat heat pipes, nanofluids technology, and plug-in connector. As a result, the energy saving effect of 50∼60% comparing with conventional air cooling system was provided in direct cooling technique with single-phase heat exchanger.

scholarly journals Comprehensive Experimental and Computational Analysis of a Fully Contained Hybrid Server Cabinet

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Kourosh Nemati ◽  
Husam A. Alissa ◽  
Bruce T. Murray ◽  
Bahgat G. Sammakia ◽  
Russell Tipton ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Data Centers ◽  
Heat Dissipation ◽  
Cooling System ◽  
Thermal Characterization ◽  
Temperature Limit ◽  
Research Area ◽  
Air Cooling ◽  
Steady State Mode ◽  
Compact Models

The rapid growth in the number of data centers combined with the high-density heat dissipation of computer and telecommunications equipment has made energy efficient thermal management of data centers a key research area. Localized hybrid air–water cooling is one approach to more effectively control the cooling when there is wide variation in the amount of dissipation in neighboring racks while the traditional air cooling approach requires overprovisioning. In a closed, hybrid air–water cooled server cabinet, the generated heat is removed by a self-contained system that does not interact with the room level air cooling system. Here, a hybrid-cooled enclosed cabinet and all its internal components were characterized experimentally in steady-state mode (e.g., experimentally determined heat-exchanger effectiveness and IT characterization). Also, a comprehensive numerical model of the cabinet was developed and validated using the experimental data. The computational model employs full numerical modeling of the cabinet geometry and compact models to represent the servers and the air/water heat exchanger. The compact models were developed based on experimental flow and thermal characterization of the internal components. The cabinet level model has been used to simulate a number of operating scenarios relevant to data center applications such as the effect of air leakage within the cabinet. The effect of the air side and the water side failure of the cooling system on the IT performance were investigated experimentally. A comparison was made of the amount of time required to exceed the operating temperature limit for the two scenarios.

The Effectiveness of Data Center Overhead Cooling in Steady and Transient Scenarios: Comparison of Downward Flow to a Cold Aisle Versus Upward Flow From a Hot Aisle

2015 ◽  
Author(s):  
Luis Silva-Llanca ◽  
Marcelo del Valle ◽  
Alfonso Ortega
Keyword(s):  
Energy Efficiency ◽  
Heat Exchanger ◽  
Cooling System ◽  
Control Flow ◽  
Air Cooling ◽  
Upward Flow ◽  
Cooling Systems ◽  
Cooling Effectiveness ◽  
Downward Flow ◽  
Pressure Drops

The most common approach to air cooling of data centers involves the pressurization of the plenum beneath the raised floor and delivery of air flow to racks via perforated floor tiles. This cooling approach is thermodynamically inefficient due in large part to the pressure losses through the tiles. Furthermore, it is difficult to control flow at the aisle and rack level since the flow source is centralized rather than distributed. Distributed cooling systems are more closely coupled to the heat generating racks. In overhead cooling systems, one can distribute flow to distinct aisles by placing the air mover and water cooled heat exchanger directly above an aisle. Two arrangements are possible: (i.) placing the air mover and heat exchanger above the cold aisle and forcing downward flow of cooled air into the cold aisle (Overhead Downward Flow (ODF)), or (ii.) placing the air mover and heat exchanger above the hot aisle and forcing heated air upwards from the hot aisle through the water cooled heat exchanger (Overhead Upward Flow (OUF)). This study focuses on the steady and transient behavior of overhead cooling systems in both ODF and OUF configurations and compares their cooling effectiveness and energy efficiency. The flow and heat transfer inside the servers and heat exchangers are modeled using physics based approaches that result in differential equation based mathematical descriptions. These models are programmed in the MATLAB™ language and embedded within a CFD computational environment (using the commercial code FLUENT™) that computes the steady or instantaneous airflow distribution. The complete computational model is able to simulate the complete flow and thermal field in the airside, the instantaneous temperatures within and pressure drops through the servers, and the instantaneous temperatures within and pressure drops through the overhead cooling system. Instantaneous overall energy consumption (1st Law) and exergy destruction (2nd Law) were used to quantify overall energy efficiency and to identify inefficiencies within the two systems. The server cooling effectiveness, based on an effectiveness-NTU model for the servers, was used to assess the cooling effectiveness of the two overhead cooling approaches.

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