Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509360
C. Lasance, R. Aarts
The paper deals with an overview of the principles of heat transfer and acoustics related to a promising alternative for fans: synthetic jet cooling. After a short discussion of the benefits, the background and the principles underlying the physics are treated. The problems with optimisation through numerical analysis are highlighted. An accompanying paper discusses the experimental results in terms of heat transfer and noise for a special embodiment: an acoustic dipole cooler.
{"title":"Synthetic Jet Cooling Part I: Overview of Heat Transfer and Acoustics","authors":"C. Lasance, R. Aarts","doi":"10.1109/STHERM.2008.4509360","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509360","url":null,"abstract":"The paper deals with an overview of the principles of heat transfer and acoustics related to a promising alternative for fans: synthetic jet cooling. After a short discussion of the benefits, the background and the principles underlying the physics are treated. The problems with optimisation through numerical analysis are highlighted. An accompanying paper discusses the experimental results in terms of heat transfer and noise for a special embodiment: an acoustic dipole cooler.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"136 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121550882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509369
A. Poppe, G. Horváth, G. Nagy, M. Rencz, V. Székely
With the increasing power dissipation increasing attention has been paid to the thermal issues in electronics design on system, board, package and chip level, including electrothermal simulation of even rather complex integrated circuits. Two distinct algorithmic directions can be distinguished in electro-thermal simulation: the simulator coupling and the simultaneous iteration or direct method. In our view the direct method is well suited for electro-thermal simulation of analog circuit blocks while simulator coupling can be used to implement logi-thermal simulation. In case of complex designs containing digital and analog blocks the two approaches can also be combined. Ideally thermal, electro-thermal and logi-thermal simulation of a circuit is performed already in the phase of conceptual design when only a rough idea exists about the final physical realization of the circuit. In any case, effect of the thermal boundary conditions of the die+package, cooling via the electrical connections to the die and the granularity of the simulation should be carefully considered.
{"title":"Electro-thermal and Logi-thermal Simulators aimed at the Temperature-aware Design of Complex Integrated Circuits","authors":"A. Poppe, G. Horváth, G. Nagy, M. Rencz, V. Székely","doi":"10.1109/STHERM.2008.4509369","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509369","url":null,"abstract":"With the increasing power dissipation increasing attention has been paid to the thermal issues in electronics design on system, board, package and chip level, including electrothermal simulation of even rather complex integrated circuits. Two distinct algorithmic directions can be distinguished in electro-thermal simulation: the simulator coupling and the simultaneous iteration or direct method. In our view the direct method is well suited for electro-thermal simulation of analog circuit blocks while simulator coupling can be used to implement logi-thermal simulation. In case of complex designs containing digital and analog blocks the two approaches can also be combined. Ideally thermal, electro-thermal and logi-thermal simulation of a circuit is performed already in the phase of conceptual design when only a rough idea exists about the final physical realization of the circuit. In any case, effect of the thermal boundary conditions of the die+package, cooling via the electrical connections to the die and the granularity of the simulation should be carefully considered.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"360 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132138401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509388
K. Maize, Y. Ezzahri, X. Wang, S. Singer, A. Majumdar, A. Shakouri
The 3ω method is a well established technique for measuring thermal conductivity of thin films and substrates. The method extracts thermal conductivity by measuring temperature response when current flows through a metal strip heater deposited on the material's surface. The metal strip is used both as heat source and temperature sensor. An important factor in the accuracy of 3ω measurements is that the current should be confined to the metal strip resistor and any leakage to the substrate will invalidate the results. This is because the heat source would no longer be localized on the surface and also because any Schottky behavior at metal/semiconductor interface will create nonlinearities that affect the 3ω signal substantially. These problems are especially important at high temperatures where thermionic emission of electrons through oxide insulation layer becomes important. In this paper we propose thermoreflectance imaging as an additional method to determine thermal conductivity of thin film materials. Because thermoreflectance measures temperatures optically, the method is less dependent on the electrical properties of the metal heater. Additionally, the temperature profile near the heat source can be used to ensure there is no defect in the thin film metal heater. Theory is presented demonstrating thermoreflectance can also be used to measure anisotropic in-plane and cross-plane thermal conductivity in thin films. Preliminary thermoreflectance measurements were analyzed at various locations on the surface of isotropic, InGaAs and anisotropic ScN/ZrN superlattice thin film 3ω test samples. Experimental results are in agreement with simulated temperature distributions.
{"title":"Measurement of Thin Film Isotropic and Anisotropic Thermal Conductivity Using 3ω and Thermoreflectance Imaging","authors":"K. Maize, Y. Ezzahri, X. Wang, S. Singer, A. Majumdar, A. Shakouri","doi":"10.1109/STHERM.2008.4509388","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509388","url":null,"abstract":"The 3ω method is a well established technique for measuring thermal conductivity of thin films and substrates. The method extracts thermal conductivity by measuring temperature response when current flows through a metal strip heater deposited on the material's surface. The metal strip is used both as heat source and temperature sensor. An important factor in the accuracy of 3ω measurements is that the current should be confined to the metal strip resistor and any leakage to the substrate will invalidate the results. This is because the heat source would no longer be localized on the surface and also because any Schottky behavior at metal/semiconductor interface will create nonlinearities that affect the 3ω signal substantially. These problems are especially important at high temperatures where thermionic emission of electrons through oxide insulation layer becomes important. In this paper we propose thermoreflectance imaging as an additional method to determine thermal conductivity of thin film materials. Because thermoreflectance measures temperatures optically, the method is less dependent on the electrical properties of the metal heater. Additionally, the temperature profile near the heat source can be used to ensure there is no defect in the thin film metal heater. Theory is presented demonstrating thermoreflectance can also be used to measure anisotropic in-plane and cross-plane thermal conductivity in thin films. Preliminary thermoreflectance measurements were analyzed at various locations on the surface of isotropic, InGaAs and anisotropic ScN/ZrN superlattice thin film 3ω test samples. Experimental results are in agreement with simulated temperature distributions.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"443 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132874233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509383
S. Narumanchi, K. Kelly, M. Mihalic, S. Gopalan, R. Hester, A. Vlahinos
In hybrid electric vehicles (HEVs), the inverter is a critical component in the power module, which conditions the flow of electric power between the AC motor and the DC battery pack. The inverter includes a number of insulated gate bipolar transistors (IGBTs), which are high frequency switches used in bi-directional DC-AC conversion. The heat generated in the IGBTs can result in degraded performance, reduced lifetime, and component failures. Heat fluxes as high as 250 W/cm2 may occur, which makes the thermal management problem quite important. In this paper, the potential of self-oscillating jets to cool IGBTs in HEV power modules is investigated experimentally. A full factorial design of experiments was used to explore the impact of nozzle design, oscillation frequency, jet flow rate, nozzle-to-target distance, and jet configuration (free-surface or submerged) on heat transfer from a simulated electronic chip surface. In the free-surface configuration, self-oscillating jets yielded up to 18% enhancement in heat transfer over a steady jet with the same parasitic power consumption. An enhancement of up to 30% for the same flow rate (and velocity since all nozzles have the same exit area) was measured. However, in the submerged configuration, amongst the nozzle designs tested, the self- oscillating jets did not yield any enhancements in heat transfer over comparable steady jets. Results also suggest that oscillating jets provide a more uniform surface temperature distribution than steady jets.
{"title":"Single-Phase Self-Oscillating Jets for Enhanced Heat Transfer","authors":"S. Narumanchi, K. Kelly, M. Mihalic, S. Gopalan, R. Hester, A. Vlahinos","doi":"10.1109/STHERM.2008.4509383","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509383","url":null,"abstract":"In hybrid electric vehicles (HEVs), the inverter is a critical component in the power module, which conditions the flow of electric power between the AC motor and the DC battery pack. The inverter includes a number of insulated gate bipolar transistors (IGBTs), which are high frequency switches used in bi-directional DC-AC conversion. The heat generated in the IGBTs can result in degraded performance, reduced lifetime, and component failures. Heat fluxes as high as 250 W/cm2 may occur, which makes the thermal management problem quite important. In this paper, the potential of self-oscillating jets to cool IGBTs in HEV power modules is investigated experimentally. A full factorial design of experiments was used to explore the impact of nozzle design, oscillation frequency, jet flow rate, nozzle-to-target distance, and jet configuration (free-surface or submerged) on heat transfer from a simulated electronic chip surface. In the free-surface configuration, self-oscillating jets yielded up to 18% enhancement in heat transfer over a steady jet with the same parasitic power consumption. An enhancement of up to 30% for the same flow rate (and velocity since all nozzles have the same exit area) was measured. However, in the submerged configuration, amongst the nozzle designs tested, the self- oscillating jets did not yield any enhancements in heat transfer over comparable steady jets. Results also suggest that oscillating jets provide a more uniform surface temperature distribution than steady jets.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116621288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509377
J. Jia, Yong-xian Guo, Weidong Wang, Shao-rong Zhou
As a promising solution for high heat flux applications, spray cooling has been widely studied in recent years. A little theoretical knowledge for the heat transfer mechanism of spray cooling is applied to practical design. In order to obtain a better understanding of spray cooling, models of the thickness and the temperature distribution within the range of the impact area were established considering the micro-scale phenomena, such as velocity slip and temperature jump. The heat transfer coefficient (HTC) was calculated. An experimental apparatus was set up to validate the HTC in the models. Experiments were performed for a commercial pressurized full cone nozzle using distilled water as the working fluid. The maximum error between the experimental HTC and the simulated HTC is within 16%.
{"title":"Modeling and Experimental Research on Spray Cooling","authors":"J. Jia, Yong-xian Guo, Weidong Wang, Shao-rong Zhou","doi":"10.1109/STHERM.2008.4509377","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509377","url":null,"abstract":"As a promising solution for high heat flux applications, spray cooling has been widely studied in recent years. A little theoretical knowledge for the heat transfer mechanism of spray cooling is applied to practical design. In order to obtain a better understanding of spray cooling, models of the thickness and the temperature distribution within the range of the impact area were established considering the micro-scale phenomena, such as velocity slip and temperature jump. The heat transfer coefficient (HTC) was calculated. An experimental apparatus was set up to validate the HTC in the models. Experiments were performed for a commercial pressurized full cone nozzle using distilled water as the working fluid. The maximum error between the experimental HTC and the simulated HTC is within 16%.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122270820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509390
M. Janicki, S. Kindermann, P. Pietrzak, B. Vermeersch, J. Banaszczyk, G. De Mey, A. Napieralski
This paper illustrates how the information obtained from dynamic thermal measurements can be used directly for the determination of certain unknown thermal data necessary for simulation purposes. Experimental heating curves of a hybrid power amplifier are processed further to compute the time constant spectra of the thermal responses and to construct their corresponding structure functions. From these functions, the values of selected thermal model parameters, such as the heat transfer coefficient or the contact resistance are determined. Owing to this approach, it is possible to eliminate certain time consuming parameter optimization procedures.
{"title":"Determining Thermal Simulation Data from Transient Measurements","authors":"M. Janicki, S. Kindermann, P. Pietrzak, B. Vermeersch, J. Banaszczyk, G. De Mey, A. Napieralski","doi":"10.1109/STHERM.2008.4509390","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509390","url":null,"abstract":"This paper illustrates how the information obtained from dynamic thermal measurements can be used directly for the determination of certain unknown thermal data necessary for simulation purposes. Experimental heating curves of a hybrid power amplifier are processed further to compute the time constant spectra of the thermal responses and to construct their corresponding structure functions. From these functions, the values of selected thermal model parameters, such as the heat transfer coefficient or the contact resistance are determined. Owing to this approach, it is possible to eliminate certain time consuming parameter optimization procedures.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121506602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509366
K. Maize, J. Christofferson, Ali Shakouri
Lock-in thermoreflectance imaging has proven effective in obtaining thermal images of active electronic and optoelectronic devices with submicron spatial resolution and 10- 50 mK temperature resolution. Thermoreflectance systems that use a lock-in method capture the steady state thermal signal but provide limited information about the thermal transient. We present a simple time series thermoreflectance method based on pulsed box-car averaging and a novel differencing technique to obtain transient thermal images with millisecond and microsecond time resolution and submicron spatial resolution. The technique relies on precise adjustment of the phase between the pulsed thermal excitation of the device and the illumination pulse used to measure the thermoreflectance change on the device. The full thermal transient pattern is reconstructed and captured in a charge coupled device (CCD) camera in a matter of minutes. Images are presented of the time evolution of the thermal signals on 40times40, and 100times100 micron square gold heaters.
{"title":"Transient Thermal Imaging Using Thermoreflectance","authors":"K. Maize, J. Christofferson, Ali Shakouri","doi":"10.1109/STHERM.2008.4509366","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509366","url":null,"abstract":"Lock-in thermoreflectance imaging has proven effective in obtaining thermal images of active electronic and optoelectronic devices with submicron spatial resolution and 10- 50 mK temperature resolution. Thermoreflectance systems that use a lock-in method capture the steady state thermal signal but provide limited information about the thermal transient. We present a simple time series thermoreflectance method based on pulsed box-car averaging and a novel differencing technique to obtain transient thermal images with millisecond and microsecond time resolution and submicron spatial resolution. The technique relies on precise adjustment of the phase between the pulsed thermal excitation of the device and the illumination pulse used to measure the thermoreflectance change on the device. The full thermal transient pattern is reconstructed and captured in a charge coupled device (CCD) camera in a matter of minutes. Images are presented of the time evolution of the thermal signals on 40times40, and 100times100 micron square gold heaters.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122996504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509362
C. F. Hsu, N. Jewell-Larsen, C. Sticht, I. Krichtafovitch, A. Mamishev
Air cooling, because of its simplicity, remains as the most popular cooling solution for microelectronics in the consumer market. However, the trend of increasing heat generation in microelectronics and the demand for compact devices result in heat fluxes approaching the limit of conventional rotary fan air cooling technology. Electrostatic fluid accelerators (EFAs), also known as electrohydrodynamic (EHD) ionic wind pumps, have the potential of becoming a critical element of electronic thermal management solutions. In this technique, application of voltage to a sharp electrode ionizes air molecules, which are propelled by the electric field, transferring part of their energy to neutral air molecules, thus creating airflow and cooling. The airflow, so called ";corona wind";, can be used discretely for hot spot cooling or integrated into a compact thermal exchange surface to decrease the fluid boundary layer and increase heat transfer enhancement. The EFA investigated in this study consists of a microfabricated AFM-cantilever corona electrode using combination of deep reactive ion etching (DRIE) and reactive ion etching (RIE), and a flat collecting electrode that doubles as the thermal exchange surface. The fabrication and testing results of a microfabricated EFA are presented in paper. Free and EFA-enhanced forced convection heat transfers are both reported by measuring the heating power difference of the collecting electrode under constant surface temperature.
{"title":"Heat Transfer Enhancement Measurement for Microfabricated Electrostatic Fluid Accelerators","authors":"C. F. Hsu, N. Jewell-Larsen, C. Sticht, I. Krichtafovitch, A. Mamishev","doi":"10.1109/STHERM.2008.4509362","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509362","url":null,"abstract":"Air cooling, because of its simplicity, remains as the most popular cooling solution for microelectronics in the consumer market. However, the trend of increasing heat generation in microelectronics and the demand for compact devices result in heat fluxes approaching the limit of conventional rotary fan air cooling technology. Electrostatic fluid accelerators (EFAs), also known as electrohydrodynamic (EHD) ionic wind pumps, have the potential of becoming a critical element of electronic thermal management solutions. In this technique, application of voltage to a sharp electrode ionizes air molecules, which are propelled by the electric field, transferring part of their energy to neutral air molecules, thus creating airflow and cooling. The airflow, so called \";corona wind\";, can be used discretely for hot spot cooling or integrated into a compact thermal exchange surface to decrease the fluid boundary layer and increase heat transfer enhancement. The EFA investigated in this study consists of a microfabricated AFM-cantilever corona electrode using combination of deep reactive ion etching (DRIE) and reactive ion etching (RIE), and a flat collecting electrode that doubles as the thermal exchange surface. The fabrication and testing results of a microfabricated EFA are presented in paper. Free and EFA-enhanced forced convection heat transfers are both reported by measuring the heating power difference of the collecting electrode under constant surface temperature.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128246037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509373
G. Shuraki, L. Keysar
The motivation, principles and realization of statistical parametric investigation as a powerful and essential tool for thermal analysis and design is presented. Examples of cases where the standard deterministic analysis provides insufficient information for the thermal design are given. The important contribution of the statistical analysis, and the quantitative data it provides for taking decisions leading to simple and reliable thermal design is demonstrated.
{"title":"Using Statistical Methods in a Parametric Thermal Analysis","authors":"G. Shuraki, L. Keysar","doi":"10.1109/STHERM.2008.4509373","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509373","url":null,"abstract":"The motivation, principles and realization of statistical parametric investigation as a powerful and essential tool for thermal analysis and design is presented. Examples of cases where the standard deterministic analysis provides insufficient information for the thermal design are given. The important contribution of the statistical analysis, and the quantitative data it provides for taking decisions leading to simple and reliable thermal design is demonstrated.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123486664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2008-03-16DOI: 10.1109/STHERM.2008.4509385
R. Udakeri, V. Mulay, D. Agonafer
The power trend for server systems continues to grow thereby making thermal management of data centers a very challenging task. Although various configurations exist, the raised floor plenum with computer room air conditioners (CRACs) providing cold air is a popular operating strategy. In prior work, numerous data center layouts employing raised floor plenum and the impact of design parameters such as plenum depth, ceiling height, cold isle location, tile openings and others on thermal performance of data center was presented. The air cooling of data center however, may not address the situation where more energy is expended in cooling infrastructure than the thermal load of data center. Revised power trend projections by ASHRAE TC 9.9 predict heat load as high as 5000 W per square feet of compute servers' equipment footprint by year 2010. These trend charts also indicate that heat load per product footprint has doubled for storage servers during 2000-2004. For the same period, heat load per product footprint for compute servers has tripled. Amongst the systems that are currently available and being shipped, many racks exceed 20 kW. Such high heat loads have raised concerns over limits of air cooling of data centers similar to air cooling of microprocessors. A hybrid cooling strategy that incorporates liquid cooling along with air cooling can be very efficient in such situations. The objective of this paper is to study and compare the performance of hybrid cooling solution in two widely used air supply configurations namely overhead supply and underfloor supply focusing on rack inlet temperature. The numerical models of a representative data center employing overhead and underfloor supply with hot aisle-cold aisle arrangement are constructed using a commercial CFD code. The effect of these configurations on rack inlet temperature is discussed.
{"title":"Comparison of Overhead Supply and Underfloor Supply with Rear Heat Exchanger in High Density Data Center Clusters","authors":"R. Udakeri, V. Mulay, D. Agonafer","doi":"10.1109/STHERM.2008.4509385","DOIUrl":"https://doi.org/10.1109/STHERM.2008.4509385","url":null,"abstract":"The power trend for server systems continues to grow thereby making thermal management of data centers a very challenging task. Although various configurations exist, the raised floor plenum with computer room air conditioners (CRACs) providing cold air is a popular operating strategy. In prior work, numerous data center layouts employing raised floor plenum and the impact of design parameters such as plenum depth, ceiling height, cold isle location, tile openings and others on thermal performance of data center was presented. The air cooling of data center however, may not address the situation where more energy is expended in cooling infrastructure than the thermal load of data center. Revised power trend projections by ASHRAE TC 9.9 predict heat load as high as 5000 W per square feet of compute servers' equipment footprint by year 2010. These trend charts also indicate that heat load per product footprint has doubled for storage servers during 2000-2004. For the same period, heat load per product footprint for compute servers has tripled. Amongst the systems that are currently available and being shipped, many racks exceed 20 kW. Such high heat loads have raised concerns over limits of air cooling of data centers similar to air cooling of microprocessors. A hybrid cooling strategy that incorporates liquid cooling along with air cooling can be very efficient in such situations. The objective of this paper is to study and compare the performance of hybrid cooling solution in two widely used air supply configurations namely overhead supply and underfloor supply focusing on rack inlet temperature. The numerical models of a representative data center employing overhead and underfloor supply with hot aisle-cold aisle arrangement are constructed using a commercial CFD code. The effect of these configurations on rack inlet temperature is discussed.","PeriodicalId":285718,"journal":{"name":"2008 Twenty-fourth Annual IEEE Semiconductor Thermal Measurement and Management Symposium","volume":"100 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122608706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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