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.2017.7991850
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.2017.7992626
B. Wunderle, D. May, M. A. Ras, J. Keller
We have developed a novel, rapid, robust and non-destructive experimental technique for in-situ monitoring of delamination of interfaces for electronic packages. The method is based on a simple thermal transducer matrix of so-called THIXELS (thermal pixels) which allows a spatially resolved real-time image of the current status of delamination. The transducers are small metal wire meanders which are driven and electrically read out using the well-known 3-omega method. This method has special advantages over other thermal contrast methods with respect to robustness, sensitivity and signal-to-noise ratio. Notable is the absence of cross-effects. The proof of concept has been furnished on an industry-grade flip-chip package with underfill on an organic substrate. The technique is especially powerful for buried interfaces, where time-honoured methods like scanning acoustic microscopy (SAM) cannot be applied. As the technique effectively performs a thermal diffusivity sensitive scan, it may not only be useful for stress testing during package qualification, but sensor applications on other fields of health monitoring seem also possible.
{"title":"Non-destructive in-situ monitoring of delamination of buried interfaces by a thermal pixel (Thixel) chip","authors":"B. Wunderle, D. May, M. A. Ras, J. Keller","doi":"10.1109/ITHERM.2017.7992626","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992626","url":null,"abstract":"We have developed a novel, rapid, robust and non-destructive experimental technique for in-situ monitoring of delamination of interfaces for electronic packages. The method is based on a simple thermal transducer matrix of so-called THIXELS (thermal pixels) which allows a spatially resolved real-time image of the current status of delamination. The transducers are small metal wire meanders which are driven and electrically read out using the well-known 3-omega method. This method has special advantages over other thermal contrast methods with respect to robustness, sensitivity and signal-to-noise ratio. Notable is the absence of cross-effects. The proof of concept has been furnished on an industry-grade flip-chip package with underfill on an organic substrate. The technique is especially powerful for buried interfaces, where time-honoured methods like scanning acoustic microscopy (SAM) cannot be applied. As the technique effectively performs a thermal diffusivity sensitive scan, it may not only be useful for stress testing during package qualification, but sensor applications on other fields of health monitoring seem also possible.","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":"132574708","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.2017.7992595
Xingjian Yu, Yupu Ma, B. Shang, Bin Xie, Qi Chen, Xiaobing Luo
Dip-transfer phosphor coating method and its benefit on enhancing angular color uniformity (ACU) of white light-emitting diodes (LEDs) were previously reported, however, for applying this method in mass production, its fluid transfer mechanism and packaging consistency needs to be further investigated. The dip-transfer process is divided into two process, they are dipping process and transfer process. In our previous study, the dipping process were studied with experiments and simulations. In this study, we further studied the transfer process with numerical simulations based on combination of the volume of fluid (VOF) method and the dynamic mesh model, four parameters include post radius, withdrawal velocity, transfer height and phosphor gel viscosity were investigated. Besides, the packaging consistency of the dip-transfer phosphor coating method was studied with experiments. The simulated results show that the transfer volume decreases with the post radius, phosphor withdrawal velocity and phosphor gel viscosity, while keep the same with the transfer height. The experimental results show that the packaging consistency is highly rely on the transfer volume, with transfer volume varies from 0.71 μl to 6.12 ul, the maximum transfer volume deviation (MTVD) changes from 6.98% to 2.31%.
{"title":"Investigation on dip-transfer phosphor coating for light-emitting diodes: Experiments and VOF simulations","authors":"Xingjian Yu, Yupu Ma, B. Shang, Bin Xie, Qi Chen, Xiaobing Luo","doi":"10.1109/ITHERM.2017.7992595","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992595","url":null,"abstract":"Dip-transfer phosphor coating method and its benefit on enhancing angular color uniformity (ACU) of white light-emitting diodes (LEDs) were previously reported, however, for applying this method in mass production, its fluid transfer mechanism and packaging consistency needs to be further investigated. The dip-transfer process is divided into two process, they are dipping process and transfer process. In our previous study, the dipping process were studied with experiments and simulations. In this study, we further studied the transfer process with numerical simulations based on combination of the volume of fluid (VOF) method and the dynamic mesh model, four parameters include post radius, withdrawal velocity, transfer height and phosphor gel viscosity were investigated. Besides, the packaging consistency of the dip-transfer phosphor coating method was studied with experiments. The simulated results show that the transfer volume decreases with the post radius, phosphor withdrawal velocity and phosphor gel viscosity, while keep the same with the transfer height. The experimental results show that the packaging consistency is highly rely on the transfer volume, with transfer volume varies from 0.71 μl to 6.12 ul, the maximum transfer volume deviation (MTVD) changes from 6.98% to 2.31%.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"8 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":"133081976","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.2017.7992520
S. Sudhakar, J. Weibel, S. Garimella
For vapor chamber heat spreaders to operate at very high heat fluxes, the internal wick layer at the evaporator must simultaneously minimize the device temperature rise and the flow resistance to liquid resupply by capillary action. Prior investigations in the literature have reported sustained capillary-fed boiling at heat fluxes as high as 1 kW/cm2 for small hotspots of significantly less than ∼1 cm2. However, the need to provide liquid feeding to avoid dryout prevents high levels of heat fluxes from being dissipated over areas any larger than localized hotspots. Thin layers of homogeneous evaporator wicks can help reduce the thermal resistance across the layer, but fail to sustain adequate liquid supply at high heat fluxes or over large areas. Thicker evaporator wicks offer greater flow cross-sections to better feed liquid to the evaporator by capillary action, but induce unacceptably large surface superheats due to the high thermal resistance across these thick layers. This work proposes and analyzes a hybrid two-layer evaporator wick for passive, high-heat-flux dissipation. A thick cap layer of wick material evenly routes liquid to a thin, low-thermal-resistance base layer through an array of vertical liquid-feeding posts. This two-layer structure decouples the functions of liquid resupply (cap layer) and capillary-fed boiling heat transfer (base layer), making the design scalable to heat input areas of ∼1 cm2 for operation at 1 kW/cm2. A model is developed to demonstrate the potential performance of a vapor chamber incorporating such a two-layer evaporator wick design and to establish the target sizes of critical wick features that must be fabricated. The model comprises simplified hydraulic and thermal resistance networks for predicting the capillary-limited maximum heat flux and the overall thermal resistance, respectively. The performance of the vapor chamber is analyzed with varying two-layer wick geometric feature sizes.
{"title":"An area-scalable two-layer evaporator wick concept for high-heat-flux vapor chambers","authors":"S. Sudhakar, J. Weibel, S. Garimella","doi":"10.1109/ITHERM.2017.7992520","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992520","url":null,"abstract":"For vapor chamber heat spreaders to operate at very high heat fluxes, the internal wick layer at the evaporator must simultaneously minimize the device temperature rise and the flow resistance to liquid resupply by capillary action. Prior investigations in the literature have reported sustained capillary-fed boiling at heat fluxes as high as 1 kW/cm2 for small hotspots of significantly less than ∼1 cm2. However, the need to provide liquid feeding to avoid dryout prevents high levels of heat fluxes from being dissipated over areas any larger than localized hotspots. Thin layers of homogeneous evaporator wicks can help reduce the thermal resistance across the layer, but fail to sustain adequate liquid supply at high heat fluxes or over large areas. Thicker evaporator wicks offer greater flow cross-sections to better feed liquid to the evaporator by capillary action, but induce unacceptably large surface superheats due to the high thermal resistance across these thick layers. This work proposes and analyzes a hybrid two-layer evaporator wick for passive, high-heat-flux dissipation. A thick cap layer of wick material evenly routes liquid to a thin, low-thermal-resistance base layer through an array of vertical liquid-feeding posts. This two-layer structure decouples the functions of liquid resupply (cap layer) and capillary-fed boiling heat transfer (base layer), making the design scalable to heat input areas of ∼1 cm2 for operation at 1 kW/cm2. A model is developed to demonstrate the potential performance of a vapor chamber incorporating such a two-layer evaporator wick design and to establish the target sizes of critical wick features that must be fabricated. The model comprises simplified hydraulic and thermal resistance networks for predicting the capillary-limited maximum heat flux and the overall thermal resistance, respectively. The performance of the vapor chamber is analyzed with varying two-layer wick geometric feature sizes.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"1 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":"124298260","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.2017.7992570
S. Alkharabsheh, Bharath Ramakrishnan, B. Sammakia
This study presents an experimental and numerical characterization of pressure drop in a commercially available direct liquid cooled (DLC) rack. It is important to investigate the pressure drop in the DLC system as it determines the required pumping power for the DLC system, which affects the energy efficiency of the data center. The main objective of this research is to assess the flow rate and pressure distributions in a DLC system to enhance the reliability and the cooling system efficiency. Other objectives of this research are to evaluate the accuracy of flow network modeling (FNM) in predicting the flow distribution in a DLC rack and identify manufacturing limitations in a commercial system that could impact the cooling system reliability. The main components of the investigated DLC system are: coolant distribution module (CDM), supply/return manifold module, and server module which contains a cold plate. Extensive experimental measurements were performed to study the flow distribution and to determine the pressure characteristic curves for the server modules and the coolant distribution module (CDM). Also, a methodology was described to develop an experimentally validated flow network model (FNM) of the DLC system to obtain high accuracy. The measurements revealed a flow maldistribution among the server modules, which is attributed to the manufacturing process of the micro-channel cold plate. The average errors in predicting the flow rate of the server module and the CDM using FNM are 2.5% and 3.8%, respectively. The accuracy and the short run time make FNM a good tool for design, analysis, and optimization for DLC systems. The pressure drop in the server module is found to account for 56% of the total pressure drop in the DLC rack. Further analysis showed that 69% of the pressure drop in the server module is associated with the module's plumbing (corrugated hoses, disconnects, fittings). The server cooling modules are designed to provide secured connections and flexibility, which come with a high pressure drop cost.
{"title":"Pressure drop analysis of direct liquid cooled (DLC) rack","authors":"S. Alkharabsheh, Bharath Ramakrishnan, B. Sammakia","doi":"10.1109/ITHERM.2017.7992570","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.7992570","url":null,"abstract":"This study presents an experimental and numerical characterization of pressure drop in a commercially available direct liquid cooled (DLC) rack. It is important to investigate the pressure drop in the DLC system as it determines the required pumping power for the DLC system, which affects the energy efficiency of the data center. The main objective of this research is to assess the flow rate and pressure distributions in a DLC system to enhance the reliability and the cooling system efficiency. Other objectives of this research are to evaluate the accuracy of flow network modeling (FNM) in predicting the flow distribution in a DLC rack and identify manufacturing limitations in a commercial system that could impact the cooling system reliability. The main components of the investigated DLC system are: coolant distribution module (CDM), supply/return manifold module, and server module which contains a cold plate. Extensive experimental measurements were performed to study the flow distribution and to determine the pressure characteristic curves for the server modules and the coolant distribution module (CDM). Also, a methodology was described to develop an experimentally validated flow network model (FNM) of the DLC system to obtain high accuracy. The measurements revealed a flow maldistribution among the server modules, which is attributed to the manufacturing process of the micro-channel cold plate. The average errors in predicting the flow rate of the server module and the CDM using FNM are 2.5% and 3.8%, respectively. The accuracy and the short run time make FNM a good tool for design, analysis, and optimization for DLC systems. The pressure drop in the server module is found to account for 56% of the total pressure drop in the DLC rack. Further analysis showed that 69% of the pressure drop in the server module is associated with the module's plumbing (corrugated hoses, disconnects, fittings). The server cooling modules are designed to provide secured connections and flexibility, which come with a high pressure drop cost.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"2672 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":"133929835","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.
{"title":"Thermal conductivity of double-wall carbon nanotube-polyanaline composites measured by a non-contact scanning hot probe technique","authors":"Adam A. Wilson, T. Borca-Tasciuc, Hong Wang, Choongho Yu","doi":"10.1109/ITHERM.2017.8023959","DOIUrl":"https://doi.org/10.1109/ITHERM.2017.8023959","url":null,"abstract":"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.","PeriodicalId":387542,"journal":{"name":"2017 16th IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems (ITherm)","volume":"81 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":"128590584","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.2017.7992529
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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：