Pub Date : 2017-05-01DOI: 10.1109/ITHERM.2017.7992639
Nianjun Fu, J. Suhling, S. Hamasha, P. Lall
When exposed to a temperature changing environment, solder joints in electronic assemblies are subjected to cyclic thermal-mechanical loading due to the mismatches in coefficients of thermal expansion (CTE) of the different assembly materials. Eventually, the cyclic loading can result in fatigue failure of solder joints, which is one of the common failure modes in electronic packaging. While it has been known that the reversal of inelastic strain can change the stress-strain behavior of materials (Bauschinger effect), there have been few prior studies on how the cycling changes the microstructure and degrades the mechanical properties of lead free solders during fatigue testing. In this investigation, we have explored the effects of mechanical cycling on the cyclic stress-strain behavior (hysteresis loop area, plastic strain range, and peak stress) and on the constitutive behavior (stress-strain and creep) of SAC305 lead free solder in fatigue testing. At the same time, effects of cycling on solder microstructure have been studied. The goal of the study was to explore the damage accumulation that occurs during fatigue testing.
{"title":"Evolution of the cyclic stress-strain and constitutive behaviors of SAC305 lead free solder during fatigue testing","authors":"Nianjun Fu, J. Suhling, S. Hamasha, P. Lall","doi":"10.1109/ITHERM.2017.7992639","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992639","url":null,"abstract":"When exposed to a temperature changing environment, solder joints in electronic assemblies are subjected to cyclic thermal-mechanical loading due to the mismatches in coefficients of thermal expansion (CTE) of the different assembly materials. Eventually, the cyclic loading can result in fatigue failure of solder joints, which is one of the common failure modes in electronic packaging. While it has been known that the reversal of inelastic strain can change the stress-strain behavior of materials (Bauschinger effect), there have been few prior studies on how the cycling changes the microstructure and degrades the mechanical properties of lead free solders during fatigue testing. In this investigation, we have explored the effects of mechanical cycling on the cyclic stress-strain behavior (hysteresis loop area, plastic strain range, and peak stress) and on the constitutive behavior (stress-strain and creep) of SAC305 lead free solder in fatigue testing. At the same time, effects of cycling on solder microstructure have been studied. The goal of the study was to explore the damage accumulation that occurs during fatigue testing.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124202225","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 : 2017-05-01DOI: 10.1109/ITHERM.2017.7991850
Z. Owens, L. Gilman, R. Dunne, J. McNulty, Abid Kemal
Thermal design of electronic enclosures for outdoor use is complicated by the need to isolate the system from moisture, dust, and other environmental contaminants. Traditionally this isolation is achieved by using sealed enclosures; however, breathable, water-resistant materials present an opportunity to achieve the thermal benefits of a vented enclosure while also maintaining the isolation offered by sealed enclosures. While breathable vents are routinely incorporated into enclosures for the purpose of pressure equalization, the concept of using breathability as a thermal management tool has not been fully realized. In this paper we describe the use of a computational fluid dynamics (CFD) model to explore the application of breathable polymers, or textiles, as a part of the enclosure and assess the thermal benefit of this approach compared to a fully sealed enclosure. The results of the study reveal that there are several water-resistant textiles, traditionally used in sportswear, that have sufficient air permeability to achieve a significant cooling benefit when used in combination with internal fans. This study also reveals that the polytetrafluoroethylene (PTFE) membrane materials that are typically used for enclosure pressure equalization are too air-impermeable to achieve a significant cooling benefit.
{"title":"Evaluation of breathable enclosures for thermal management of outdoor electronics","authors":"Z. Owens, L. Gilman, R. Dunne, J. McNulty, Abid Kemal","doi":"10.1109/ITHERM.2017.7991850","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7991850","url":null,"abstract":"Thermal design of electronic enclosures for outdoor use is complicated by the need to isolate the system from moisture, dust, and other environmental contaminants. Traditionally this isolation is achieved by using sealed enclosures; however, breathable, water-resistant materials present an opportunity to achieve the thermal benefits of a vented enclosure while also maintaining the isolation offered by sealed enclosures. While breathable vents are routinely incorporated into enclosures for the purpose of pressure equalization, the concept of using breathability as a thermal management tool has not been fully realized. In this paper we describe the use of a computational fluid dynamics (CFD) model to explore the application of breathable polymers, or textiles, as a part of the enclosure and assess the thermal benefit of this approach compared to a fully sealed enclosure. The results of the study reveal that there are several water-resistant textiles, traditionally used in sportswear, that have sufficient air permeability to achieve a significant cooling benefit when used in combination with internal fans. This study also reveals that the polytetrafluoroethylene (PTFE) membrane materials that are typically used for enclosure pressure equalization are too air-impermeable to achieve a significant cooling benefit.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130893825","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 : 2017-05-01DOI: 10.1109/ITHERM.2017.7992611
Pavan Rajmane, Hassaan Ahmad Khan, A. Doiphode, Unique Rahangdale, D. Agonafer, A. Lohia, S. Kummerl, L. Nguyen
Various studies have been conducted to study the effect of varying board thickness on thermo-mechanical reliability of BGA packages. Wafer level chip scale packages (WLCSP) have also been studied in this regard to determine the effect of PCB build-up thickness on the solder joint reliability [1]. The studies clearly demonstrate that the thinner Printed Circuit Boards (PCBs) result in longer thermo-mechanical fatigue life of solder joints for BGA. With the literature and past trends supporting the idea of thinner boards, manufacturer opted to move forward by decreasing the thickness of their PCBs to improve the reliability of their packages. The thickness was reduced from 1mm to 0.7mm by decreasing the thicknesses of individual layers and keeping the total number of layers constant. When subjected to thermal cycling, it was observed that 0.7mm board was failing earlier than the 1mm board. Since this behavior of a WLCSP contrasts with the past trends, it required extensive study to determine and understand the pre-mature physics of failure/causality of failure in 0.7mm board. In this paper, an effort is made to understand the mechanism which is causing an early failure in the thinner board. The effect of number & thicknesses of core layers, prepregs and Cu layers in the board has been studied through material characterization of both 1mm and 0.7mm boards. Further, a design optimization account has also been presented to improve the thermo-mechanical reliability of this package.
{"title":"Failure mechanisms of boards in a thin wafer level chip scale package","authors":"Pavan Rajmane, Hassaan Ahmad Khan, A. Doiphode, Unique Rahangdale, D. Agonafer, A. Lohia, S. Kummerl, L. Nguyen","doi":"10.1109/ITHERM.2017.7992611","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992611","url":null,"abstract":"Various studies have been conducted to study the effect of varying board thickness on thermo-mechanical reliability of BGA packages. Wafer level chip scale packages (WLCSP) have also been studied in this regard to determine the effect of PCB build-up thickness on the solder joint reliability [1]. The studies clearly demonstrate that the thinner Printed Circuit Boards (PCBs) result in longer thermo-mechanical fatigue life of solder joints for BGA. With the literature and past trends supporting the idea of thinner boards, manufacturer opted to move forward by decreasing the thickness of their PCBs to improve the reliability of their packages. The thickness was reduced from 1mm to 0.7mm by decreasing the thicknesses of individual layers and keeping the total number of layers constant. When subjected to thermal cycling, it was observed that 0.7mm board was failing earlier than the 1mm board. Since this behavior of a WLCSP contrasts with the past trends, it required extensive study to determine and understand the pre-mature physics of failure/causality of failure in 0.7mm board. In this paper, an effort is made to understand the mechanism which is causing an early failure in the thinner board. The effect of number & thicknesses of core layers, prepregs and Cu layers in the board has been studied through material characterization of both 1mm and 0.7mm boards. Further, a design optimization account has also been presented to improve the thermo-mechanical reliability of this package.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128645058","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 : 2017-05-01DOI: 10.1109/ITHERM.2017.7992546
David M. Hymas, Martinus A. Arle, Farah Singer, A. Shooshtari, M. Ohadi
The present study builds upon our prior work in integrating additive manufacturing into next-generation heat/mass exchanger devices. In this paper, we will report an analysis of the fabrication, testing, and performance of an additively manufactured polymer composite heat exchanger. This heat exchanger utilizes a novel approach to achieve enhanced air-side heat transfer coefficients and overall mass reduction. This device relies on the Cross-Media Fiber concept where two fluid flows are thermally linked by high-conductivity fins, passing through a low-conductivity channel wall. Through this, the authors have met the required pressure containment, coefficient of performance, and heat flow rate targets, which were 28 psig, 100 and 150 W respectively. The advances that are discussed throughout this paper have allowed this novel polymer composite heat exchanger to be produced through a newly developed form of additive manufacturing that can potentially lead to the economical production of large scale Cross-Media Fiber heat exchangers.
{"title":"Enhanced air-side heat transfer in an additively manufactured polymer composite heat exchanger","authors":"David M. Hymas, Martinus A. Arle, Farah Singer, A. Shooshtari, M. Ohadi","doi":"10.1109/ITHERM.2017.7992546","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992546","url":null,"abstract":"The present study builds upon our prior work in integrating additive manufacturing into next-generation heat/mass exchanger devices. In this paper, we will report an analysis of the fabrication, testing, and performance of an additively manufactured polymer composite heat exchanger. This heat exchanger utilizes a novel approach to achieve enhanced air-side heat transfer coefficients and overall mass reduction. This device relies on the Cross-Media Fiber concept where two fluid flows are thermally linked by high-conductivity fins, passing through a low-conductivity channel wall. Through this, the authors have met the required pressure containment, coefficient of performance, and heat flow rate targets, which were 28 psig, 100 and 150 W respectively. The advances that are discussed throughout this paper have allowed this novel polymer composite heat exchanger to be produced through a newly developed form of additive manufacturing that can potentially lead to the economical production of large scale Cross-Media Fiber heat exchangers.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126587552","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 : 2017-05-01DOI: 10.1109/ITHERM.2017.7992461
A. Ziabari, Y. Xuan, J. Bahk, Maryam Parsa, P. Ye, A. Shakouri
Thermoreflectance thermal imaging technique uses light in the visible wavelength range and has a diffraction limit of ∼250nm. Despite that TR is still capable of acquiring temperature signal from devices smaller in size down to ∼3x below diffraction limit. Below diffraction limit, the detected thermoreflectance signal underestimates the true measured temperature by 360%. Image blurring was used in the forward problem to explain the apparent temperature of the device quite accurately. In most applications, there is no unambiguous model of the device temperature for forward problem and one needs to reconstruct the true temperature profiles of the sub-diffraction devices from their measured TR images. This is an ill-posed inverse problem which may not have a unique solution. Here, a maximum-a-posteriori (MAP) image reconstruction technique is used along with an Iterative Coordinate Descent (ICD) Optimization approach to solve this inverse problem and restore the true temperature profile of the devices. Preliminary results show that temperature of sub-diffraction heater lines down to ∼150nm can be accurately estimated.
{"title":"Sub-diffraction thermoreflectance thermal imaging using image reconstruction","authors":"A. Ziabari, Y. Xuan, J. Bahk, Maryam Parsa, P. Ye, A. Shakouri","doi":"10.1109/ITHERM.2017.7992461","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992461","url":null,"abstract":"Thermoreflectance thermal imaging technique uses light in the visible wavelength range and has a diffraction limit of ∼250nm. Despite that TR is still capable of acquiring temperature signal from devices smaller in size down to ∼3x below diffraction limit. Below diffraction limit, the detected thermoreflectance signal underestimates the true measured temperature by 360%. Image blurring was used in the forward problem to explain the apparent temperature of the device quite accurately. In most applications, there is no unambiguous model of the device temperature for forward problem and one needs to reconstruct the true temperature profiles of the sub-diffraction devices from their measured TR images. This is an ill-posed inverse problem which may not have a unique solution. Here, a maximum-a-posteriori (MAP) image reconstruction technique is used along with an Iterative Coordinate Descent (ICD) Optimization approach to solve this inverse problem and restore the true temperature profile of the devices. Preliminary results show that temperature of sub-diffraction heater lines down to ∼150nm can be accurately estimated.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127462837","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 : 2017-05-01DOI: 10.1109/ITHERM.2017.8023956
M. Arie, A. Shooshtari, M. Ohadi
Additive manufacturing is a fast-growing technique due to its ability to fabricate complex objects layer by layer from a preprogrammed digital model. Additive manufacturing can greatly enhance the heat exchanger manufacturing field, as it makes possible the fabrication of complex heat exchanger designs that are challenging to fabricate using conventional methods. In the present work, an air-to-water manifold-microchannel heat exchanger made of titanium alloy (Ti64) with size of 15 cm x 15 cm x 3.2 cm was fabricated using direct metal laser sintering (DMLS) additive manufacturing technique. The manifoldmicrochannel feeds the fluid flow into an array of parallel microchannels for better flow distribution as well as short flow travel length, thus yielding significantly enhanced heat transfer performance with low pressure drop penalty. Upon successful fabrication, the heat exchanger was experimentally tested, and the results were analyzed against conventional heat transfer surfaces. Based on the experimental results, for the case where the heat exchanger heat flow rate is 900 W, air-side Reynolds number is less than 100 and the temperature difference between the inlet air and water temperature is 27.5°C, heat transfer coefficient of 180 W/m2K and pressure drop of 100 Pa are observed. Compared to the conventional surfaces like wavy fin, louvered fin, and plain plate fins, up to 80%, 120%, and 190% improvement in air-side heat transfer coefficients were recorded, respectively, with an air-side pressure drop of less than 100 Pa. The results strongly suggest that additive manufacturing could be implemented for materials and complex designs that are otherwise difficult to fabricate with conventional technologies.
增材制造是一种快速发展的技术，因为它能够从预编程的数字模型逐层制造复杂的物体。增材制造可以极大地增强热交换器制造领域，因为它可以制造复杂的热交换器设计，这是使用传统方法制造的挑战。本文采用直接金属激光烧结(DMLS)增材制造技术，制作了尺寸为15 cm x 15 cm x 3.2 cm的钛合金(Ti64)气-水歧管-微通道热交换器。多管式微通道将流体输送到一系列平行的微通道中，以实现更好的流动分配和更短的流动行程长度，从而显著提高传热性能，同时降低压降损失。在制造成功后，对换热器进行了实验测试，并将结果与传统的传热表面进行了分析。实验结果表明，当换热器热流量为900 W，空气侧雷诺数小于100，进水温差为27.5℃时，换热系数为180 W/m2K，压降为100 Pa。与传统的波纹翅片、百叶翅片和平面翅片等表面相比，空气侧传热系数分别提高了80%、120%和190%，而空气侧压降小于100 Pa。结果强烈表明，增材制造可以用于材料和复杂的设计，否则难以用传统技术制造。
{"title":"Air side enhancement of heat transfer in an additively manufactured 1 kW heat exchanger for dry cooling applications","authors":"M. Arie, A. Shooshtari, M. Ohadi","doi":"10.1109/ITHERM.2017.8023956","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.8023956","url":null,"abstract":"Additive manufacturing is a fast-growing technique due to its ability to fabricate complex objects layer by layer from a preprogrammed digital model. Additive manufacturing can greatly enhance the heat exchanger manufacturing field, as it makes possible the fabrication of complex heat exchanger designs that are challenging to fabricate using conventional methods. In the present work, an air-to-water manifold-microchannel heat exchanger made of titanium alloy (Ti64) with size of 15 cm x 15 cm x 3.2 cm was fabricated using direct metal laser sintering (DMLS) additive manufacturing technique. The manifoldmicrochannel feeds the fluid flow into an array of parallel microchannels for better flow distribution as well as short flow travel length, thus yielding significantly enhanced heat transfer performance with low pressure drop penalty. Upon successful fabrication, the heat exchanger was experimentally tested, and the results were analyzed against conventional heat transfer surfaces. Based on the experimental results, for the case where the heat exchanger heat flow rate is 900 W, air-side Reynolds number is less than 100 and the temperature difference between the inlet air and water temperature is 27.5°C, heat transfer coefficient of 180 W/m2K and pressure drop of 100 Pa are observed. Compared to the conventional surfaces like wavy fin, louvered fin, and plain plate fins, up to 80%, 120%, and 190% improvement in air-side heat transfer coefficients were recorded, respectively, with an air-side pressure drop of less than 100 Pa. The results strongly suggest that additive manufacturing could be implemented for materials and complex designs that are otherwise difficult to fabricate with conventional technologies.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127786728","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 : 2017-05-01DOI: 10.1109/ITHERM.2017.7992485
Chirag R. Kharangate, Hyoungsoon Lee, Tanya Liu, K. Jung, M. Iyengar, C. Malone, M. Asheghi, K. Goodson
Microprocessor are seeing an exponential rise in switching speeds and transistor densities, which are leading to significantly higher heat fluxes. Two-phase schemes utilizing boiling are becoming very popular over the past few years due to their ability to tackle much higher heat dissipation challenges in comparison to single-phase schemes. In this paper, we investigate thermal performance and pressure drop for microchannels in single-phase flows and two-phase boiling flows. Microchannel configurations with three different hydraulic diameters were investigated: 909 pm, 191 pm, and 95 pm. Three different working fluids were compared: water is used for the single-phase study, R2345fa and HFE7000 for the two-phase study. As expected, increase in hydraulic diameter, decreases the pressure drop and increases the thermal resistance for a fixed flow rate. Two-phase flows show higher pressure drop and lower thermal resistance in comparison to single-phase flows. Two factors contribute to lower resistances in two-phase flow; lower convective resistance due to high heat transfer, and negative advection resistances due to high pressure drop. Some two-phase test cases predict sub-atmospheric exit pressures, making those inlet conditions impractical in real two-phase flow loop designs. To avoid sub-atmospheric pressure predictions in two-phase flow, the total thermal resistance should be calculated based on the exit temperature of the fluid. Using this, decrease in hydraulic diameter of the microchannel from 191 pm to 95 pm, shows increase in the total thermal resistance due to increased pressure drop impact on mean fluid temperature.
{"title":"Thermal modeling of single-phase and two-phase 2D-chip cooling using microchannels","authors":"Chirag R. Kharangate, Hyoungsoon Lee, Tanya Liu, K. Jung, M. Iyengar, C. Malone, M. Asheghi, K. Goodson","doi":"10.1109/ITHERM.2017.7992485","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992485","url":null,"abstract":"Microprocessor are seeing an exponential rise in switching speeds and transistor densities, which are leading to significantly higher heat fluxes. Two-phase schemes utilizing boiling are becoming very popular over the past few years due to their ability to tackle much higher heat dissipation challenges in comparison to single-phase schemes. In this paper, we investigate thermal performance and pressure drop for microchannels in single-phase flows and two-phase boiling flows. Microchannel configurations with three different hydraulic diameters were investigated: 909 pm, 191 pm, and 95 pm. Three different working fluids were compared: water is used for the single-phase study, R2345fa and HFE7000 for the two-phase study. As expected, increase in hydraulic diameter, decreases the pressure drop and increases the thermal resistance for a fixed flow rate. Two-phase flows show higher pressure drop and lower thermal resistance in comparison to single-phase flows. Two factors contribute to lower resistances in two-phase flow; lower convective resistance due to high heat transfer, and negative advection resistances due to high pressure drop. Some two-phase test cases predict sub-atmospheric exit pressures, making those inlet conditions impractical in real two-phase flow loop designs. To avoid sub-atmospheric pressure predictions in two-phase flow, the total thermal resistance should be calculated based on the exit temperature of the fluid. Using this, decrease in hydraulic diameter of the microchannel from 191 pm to 95 pm, shows increase in the total thermal resistance due to increased pressure drop impact on mean fluid temperature.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122345005","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 : 2017-05-01DOI: 10.1109/ITHERM.2017.7992587
Yan Cui, Charles Ingalz, Tianyi Gao, A. Heydari
Total Cost of Ownership (TCO) is a comprehensive tool for cost estimation, provisioning, and decision making in a data center. The goal of this paper is to introduce an accurate yet simple model of TCO for data centers. TCO-estimation helps to clear the cost trade-offs, highlights the most impactful parameters on TCO in a datacenter which helps us to focus on research and development efforts to optimize such parameters. In a nutshell TCO consists of five major costs: infrastructure, server acquisition, power utilization, networking equipment, and maintenance cost. Each of these costs needs to be estimated as accurate as possible. This version of TCO model has distinguished features such as capturing different options for utility billing, Power Usage Effectiveness (PUE) as a factor of saving power cost, and comprehensive maintenance model. By studying a few cases such as comparing different cooling solutions, high-efficiency power delivery solutions, and data center parametric sensitivity analysis, we can show the power of this analytical yet simple tool to connect the IT performance to the business performance in a data center.
{"title":"Total cost of ownership model for data center technology evaluation","authors":"Yan Cui, Charles Ingalz, Tianyi Gao, A. Heydari","doi":"10.1109/ITHERM.2017.7992587","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992587","url":null,"abstract":"Total Cost of Ownership (TCO) is a comprehensive tool for cost estimation, provisioning, and decision making in a data center. The goal of this paper is to introduce an accurate yet simple model of TCO for data centers. TCO-estimation helps to clear the cost trade-offs, highlights the most impactful parameters on TCO in a datacenter which helps us to focus on research and development efforts to optimize such parameters. In a nutshell TCO consists of five major costs: infrastructure, server acquisition, power utilization, networking equipment, and maintenance cost. Each of these costs needs to be estimated as accurate as possible. This version of TCO model has distinguished features such as capturing different options for utility billing, Power Usage Effectiveness (PUE) as a factor of saving power cost, and comprehensive maintenance model. By studying a few cases such as comparing different cooling solutions, high-efficiency power delivery solutions, and data center parametric sensitivity analysis, we can show the power of this analytical yet simple tool to connect the IT performance to the business performance in a data center.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128018031","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 : 2017-05-01DOI: 10.1109/ITHERM.2017.8023959
Adam A. Wilson, T. Borca-Tasciuc, Hong Wang, Choongho Yu
This paper presents a method for determining thermal conductivity of film samples using the non-contact mode scanning hot probe technique at probe-to-sample distances such that Fourier law heat conduction across the air gap occurs. A method for calibrating non-contact thermal exchange parameters between probe and sample using a single reference sample is proposed and the obtained value of sample thermal conductivity is presented for thin film samples of PANI-CSA infused with varying concentrations of DW-CNTs. Two- to three-fold increase in film thermal conductivity (from 0.4 Wm-1K-1) for the un-doped polymer to 0.8-1.1 Wm-1K-1) is observed for DW-CNT concentration of less than 20% by weight, and a more than seven-fold increase (3.0 Wm-1K-1) is reported for DW-CNT concentration of 30% by weight.
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Pub Date : 2017-05-01DOI: 10.1109/ITHERM.2017.7992529
E. Dede, Feng Zhou, S. Joshi
Wide band-gap (WBG) power semiconductor devices are being researched in order to meet future high power density electronic packaging targets for a range of power conversion applications. All power devices may be classified based on the current flow direction, namely lateral versus vertical, and for both types, the device junction temperature is determined, in part, by the package thermal resistance. For electrified vehicle applications, where vertical current device architectures are preferred, the vertical configuration leads to current rates that are higher than those found in a lateral device, and this in turn leads to large heat fluxes (∼1 kW/cm2) for large bare dies (∼1 cm2). Considering the challenges associated with the vertical current WBG device structure, three embedded cooling concepts are described. One strategy is selected for initial investigation, where a multi-layer straight microchannel chip-scale cooler is fabricated and thermal-fluid performance characteristics of the device are experimentally plus numerically evaluated. Performance limitations of the design are highlighted, and ongoing work focused on fabrication of a design that exploits jet impingement plus fluid flow through an optimized microchannel topology is described. Discussion regarding device electrical performance and the separation of the vertical current field from the coolant flow is provided.
{"title":"Concepts for embedded cooling of vertical current wide band-gap semiconductor devices","authors":"E. Dede, Feng Zhou, S. Joshi","doi":"10.1109/ITHERM.2017.7992529","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992529","url":null,"abstract":"Wide band-gap (WBG) power semiconductor devices are being researched in order to meet future high power density electronic packaging targets for a range of power conversion applications. All power devices may be classified based on the current flow direction, namely lateral versus vertical, and for both types, the device junction temperature is determined, in part, by the package thermal resistance. For electrified vehicle applications, where vertical current device architectures are preferred, the vertical configuration leads to current rates that are higher than those found in a lateral device, and this in turn leads to large heat fluxes (∼1 kW/cm2) for large bare dies (∼1 cm2). Considering the challenges associated with the vertical current WBG device structure, three embedded cooling concepts are described. One strategy is selected for initial investigation, where a multi-layer straight microchannel chip-scale cooler is fabricated and thermal-fluid performance characteristics of the device are experimentally plus numerically evaluated. Performance limitations of the design are highlighted, and ongoing work focused on fabrication of a design that exploits jet impingement plus fluid flow through an optimized microchannel topology is described. Discussion regarding device electrical performance and the separation of the vertical current field from the coolant flow is provided.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128646980","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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