Optimized Ionic Wind-Based Cooling Microfabricated Devices for Improving a Measured Coefficient of Performance

2011 ◽  
Author(s):  
Andojo Ongkodjojo ◽  
Alexis R. Abramson ◽  
Norman C. Tien
Keyword(s):  
Three Dimensional ◽  
Heat Removal ◽  
Temperature Data ◽  
Coefficient Of Performance ◽  
Comsol Multiphysics ◽  
Air Cooling ◽  
Ionic Wind ◽  
Cooling Systems ◽  
Removal Capacity ◽  
Cooling Technology

This work is a continuation of previous investigations aimed at developing an innovative microfabricated air-cooling technology that employs an electrohydrodynamic corona discharge (i.e. ionic wind pump) [1], [2]. This technology enables the miniaturization of cooling systems for next generation electronics. Our single ionic wind pump element consists of two parallel collecting electrodes between which a single emitting tip is positioned. Two-dimensional (2-D) and three-dimensional (3-D) simulations using COMSOL Multiphysics™ are additionally employed to predict the temperature distribution, the flow field, and the heat removal capacity of the device in operation. One such model utilizes a small gap between collector and emitter electrodes and demonstrates an improvement in the COP (coefficient of performance) of a single device. Comparisons are made with experimental temperature data on an actual device. The purpose of this work is therefore to optimize the performance of a single microfabricated ionic wind pump to enable the development of an array of these elements for use in larger-scale heat transfer applications.

Design, Modeling, and Optimization for Highly Efficient Ionic Wind-Based Cooling Microfabricated Devices

2010 ◽  
Author(s):  
Andojo Ongkodjojo ◽  
Alexis R. Abramson ◽  
Norman C. Tien
Keyword(s):  
Three Dimensional ◽  
Heat Removal ◽  
Power Input ◽  
Air Cooling ◽  
Ionic Wind ◽  
Electronic Components ◽  
Dimensional Array ◽  
Overall Heat Transfer Coefficient ◽  
Cooling Effects ◽  
Cooling Technology

The purpose of this work is to re-design, model and optimize a single microfabricated ionic wind pump device [1]. The device could then be employed in a three-dimensional array for use in larger-scale microchip cooling and enhanced thermal spreading applications. The innovative microfabricated air-cooling technology employs an electrohydrodynamic corona discharge (i.e. ionic wind pump) for efficient heat removal from electronic components. Our single ionic wind pump element consists of two parallel collecting electrodes between which a single emitting tip is positioned. The collector electrodes are patterned with a grid structure, which enhances the overall heat transfer coefficient and facilitates a batch and IC compatible process. Various design configurations are explored and modeled computationally to investigate their influence on the cooling phenomenon. In particular, COMSOL Multiphysics™ is employed to computationally explore the effects of collector-emitter configuration on the electrohydrodynamic phenomenon, the flow field and resulting cooling effects. Using both computational and experimental results, we estimate that a two-dimensional array of microfabricated ionic wind pumps covering approximately 2″ square should be able to dissipate greater than 2 W of heat, using about 1/5 the power input as a conventional fan.

Electrohydrodynamic Microfabricated Ionic Wind Pumps for Thermal Management Applications

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Andojo Ongkodjojo Ong ◽  
Alexis R. Abramson ◽  
Norman C. Tien
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Management ◽  
High Reliability ◽  
Semiconductor Industry ◽  
Heat Removal ◽  
Coefficient Of Performance ◽  
Air Cooling ◽  
Ionic Wind

This work demonstrates an innovative microfabricated air-cooling technology that employs an electrohydrodynamic (EHD) corona discharge (i.e., ionic wind pump) for electronics cooling applications. A single, microfabricated ionic wind pump element consists of two parallel collecting electrodes between which a single emitting tip is positioned. A grid structure on the collector electrodes can enhance the overall heat-transfer coefficient and facilitate an IC compatible batch process. The optimized devices studied exhibit an overall device area of 5.4 mm × 3.6 mm, an emitter-to-collector gap of ∼0.5 mm, and an emitter curvature radius of ∼12.5 μm. The manufacturing process developed for the device uses glass wafers, a single mask-based photolithography process, and a low-cost copper-based electroplating process. Various design configurations were explored and modeled computationally to investigate their influence on the cooling phenomenon. The single devices provide a high heat-transfer coefficient of up to ∼3200 W/m2 K and a coefficient of performance (COP) of up to ∼47. The COP was obtained by dividing the heat removal enhancement, ΔQ by the power consumed by the ionic wind pump device. A maximum applied voltage of 1.9 kV, which is equivalent to approximately 38 mW of power input, is required for operation, which is significantly lower than the power required for the previously reported devices. Furthermore, the microfabricated single device exhibits a flexible and small form factor, no noise generation, high efficiency, large heat removal over a small dimension and at low power, and high reliability (no moving parts); these are characteristics required by the semiconductor industry for next generation thermal management solutions.

Improving the Performance of the Micro Jet Array Air Cooling MEMS Device Using CFD

2005 ◽  
Author(s):  
Yangki Jung ◽  
R. Panneer Selvam
Keyword(s):  
Heat Transfer ◽  
Computer Modeling ◽  
Three Dimensional ◽  
Measurement Data ◽  
Heat Removal ◽  
Navier Stokes ◽  
Air Cooling ◽  
Removal Capacity ◽  
Optimum Model ◽  
Jet Array

In this work ways to improve the performance of the MJA is investigated using computer modeling. Finite-difference method is used to analyze and understand the heat transfer mechanism in the MEMS based air micro-jet array (MJA) impinging cooling device. The three-dimensional Navier-Stokes (NS) equations using the compressible flow are solved. The computed temperature distribution at the bottom of the MJA is in good agreement with the experimental measurement data. To improve the heat transfer performance, an optimum model is developed. This enhances the heat removal capacity about 100% (0.5 W/cm2°C). The details of computer modeling and the flow visualization to understand the flow and heat transfer in the MJA are presented.   This paper was also originally published as part of the Proceedings of the ASME 2005 Heat Transfer Summer Conference.

Systematic Assessment of Combustion Turbine Inlet Air-Cooling Techniques

2005 ◽  
Vol 127 (1) ◽  
pp. 159-169 ◽  
Author(s):  
Abdalla M. Al-Amiri ◽  
Montaser M. Zamzam
Keyword(s):  
Air Temperature ◽  
Evaporative Cooling ◽  
Heat Rate ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Air Cooling ◽  
Cooling Systems ◽  
Turbine Inlet ◽  
Wide Range ◽  
The Impact

The current study is centered on assessing the benefits of incorporating combustion turbine inlet air-cooling systems into a reference combustion turbine plant, which is based on a simple cycle under base load mode. Actual climatic conditions of a selected site were examined thoroughly to identify the different governing weather patterns. The main performance characteristics of both refrigerative and evaporative cooling systems were explored by examining the effect of several parameters including inlet air temperature, airflow-to-turbine output ratio, coefficient of performance (for refrigerative cooling systems), and evaporative degree hours (for evaporative cooling systems). The impact of these parameters was presented against the annual gross energy increase, average heat rate reduction, cooling load requirements and net power increase. Finally, a feasibility design chart was constructed to outline the economic returns of employing a refrigerative cooling unit against different prescribed inlet air temperature values using a wide range of combustion turbine mass flow rates.

Advanced Technology for Server Cooling

2005 ◽  
Author(s):  
Ralph L. Webb ◽  
Hasan Nasir
Keyword(s):  
Cooling Water ◽  
Heat Removal ◽  
Heat Sinks ◽  
Advanced Technology ◽  
Air Cooling ◽  
Performance Predictions ◽  
Micro Channels ◽  
Cooling Technology ◽  
Performance Results ◽  
Heat Loads

This paper reports work on advanced cooling technology for servers. The air cooling load on the rack may be enhanced using highly compact Copper/Brass “flat tube” water-cooled heat exchangers that are integrated into the rack frame. The cooling water is supplied by a water chiller. Analysis shows that it is possible to provide cooling (UA/Afr) in the range of 670–1000 W/m2-K, where the m2 is the core frontal area. Also analyzed and compared are advanced technology CPU heat sinks — a thermo-syphon concept and a liquid micro-channel heat sink. The thermo-syphon may be used in a compact thermal-bus concept for heat removal from multiple CPUs. Used with boiling on an enhanced copper boiling surface in a thermo-syphon, heat loads in excess of 75 W/m2-K are possible. The heat removed at each CPU in the chassis is rejected to water flow in a compact water cooled condenser. Performance results of the thermo-syphon concept are predicted, obstacles associated with increasing performance are discussed, and possible solutions are proposed. Performance predictions were also made for water cooled: (1) Copper micro-channels as an attached external sink and (2) Silicon micro-channels integral to the silicon CPU die. It is shown that micro-channels integrated into the silicon die do not offer significant advantage over copper micro-channels.   This paper was also originally published as part of the Proceedings of the ASME 2005 Heat Transfer Summer Conference.

Modeling Thermoelectric Device Enhancement of Heat Sink Performance

2007 ◽  
Author(s):  
Richard I. Roser ◽  
Robert M. Smythe ◽  
Malkiat Singh
Keyword(s):  
Thermal Resistance ◽  
Thermoelectric Material ◽  
Heat Sink ◽  
Graphical Representation ◽  
Heat Removal ◽  
Effect Of Temperature ◽  
Thermoelectric Device ◽  
Air Cooling ◽  
Material Parameters ◽  
Removal Capacity

Increased power density is straining the ability of air-cooled heat sink technologies to provide adequate cooling for heat-generating components. Several technologies are under investigation as replacements for air-cooling. Under specific conditions, a well-selected thermoelectric device [TED] can act as an enhancement to a heat sink’s heat removal capacity or allow it to achieve lower temperatures. Such improvements to heat sink performance using a thermoelectric device are possible without increasing airflow or heat sink dimensions. Proper sizing of this kind of optimized thermoelectric system involves consideration of multiple conditions, including the amount of heat being generated, the temperatures involved (typically, target case temperature and expected ambient temperature), and available voltage and current. Although thermoelectric devices are often thought of as inefficient, with Coefficients of Performance [COP] of less than 1, a well-selected TED can have a COP of much greater than 10. Existing methods for thermoelectric optimization, for the sake of simplicity, often ignore the thermal resistance of the heat sink or ignore the effect of temperature dependence of the thermoelectric material parameters of resistivity, thermal conductivity, and thermopower. To correctly include these factors in the design of the TED, a methodology has been developed to determine an optimum device while simultaneously considering the input parameters of θCA (case to ambient thermal resistance), heat load, target cooling temperatures, and available DC power. The method is iterative, involving the use of given input conditions to yield an estimate for expected final temperature conditions, which are used to produce an initial estimate of the thermoelectric material parameters, which in turn are used to calculate the optimized device. The performance of this device is calculated to determine a new estimate for temperatures and material parameters. The process is repeated until convergence occurs for the device design. The methodology can also demonstrate the performance benefits of integrating a TED into an existing conventional fan/sink system, and also describes conditions that are unsuitable for the use of TED’s. Graphical representation of the information can be readily generated as an aid to design.

scholarly journals Simulation and experimental study on performance analysis of solar photovoltaic integrated thermoelectric cooler using MATLAB Simulink

2021 ◽  
pp. 301-301
Author(s):  
Lalith Nadimuthu ◽  
Divya Selvaraj ◽  
Kirubakaran Victor
Keyword(s):  
Cooling System ◽  
Thermoelectric Module ◽  
Heat Removal ◽  
Coefficient Of Performance ◽  
Photovoltaic Module ◽  
Air Cooling ◽  
Thermoelectric Cooler ◽  
Solar Photovoltaic ◽  
Matlab Simulink ◽  
Effective Heat

The present study investigates the performance of solar photovoltaic integrated thermoelectric cooler (TEC) using MATLAB Simulink. The enhancement of efficiency has been achieved using an effective heat removal mechanism from the hot side heat sink. Since the hot side temperature is a crucial parameter. The intrinsic material properties like Seebeck coefficient (?), Thermal Conductance (K) and Electrical resistance (R) of the thermoelectric module are carefully estimated using analytical method and reported. The MATLAB Simulink Peltier module is developed based on the estimated intrinsic properties. The effect of system Voltage (V) and Current (A) on the thermal parameters like cooling capacity (QC) and Coefficient of performance (COP) has been investigated. The simulation study is validated by conducting a series of experimental analysis. The experimental model is equipped with a 100 Wp polycrystalline solar photovoltaic module to integrate and power the 12V/5 A of the 60-Watt thermoelectric cooler. Moreover, the results reveal that there is a significant effect of ambient and hot side temperature on the thermoelectric cooler performance. The fin-type conductive mode of heat transfer mechanism is adopted along with the convective forced air-cooling system to achieve effective heat removal from the hot side. The infrared thermographic investigation is carried out for ascertaining effective heat removal.

scholarly journals Performance Analysis of Hybrid Desiccant Cooling System with Enhanced Dehumidification Capability Using TRNSYS

2021 ◽  
Vol 11 (7) ◽  
pp. 3236
Author(s):  
Ji Hyeok Kim ◽  
Joon Ahn
Keyword(s):  
Thermal Comfort ◽  
Cooling System ◽  
Operation Mode ◽  
Heat Removal ◽  
Simulation Models ◽  
Coefficient Of Performance ◽  
Dimensional Structure ◽  
Dominant Factor ◽  
Exhaust Heat ◽  
Chp System

In a field test of a hybrid desiccant cooling system (HDCS) linked to a gas engine cogeneration system (the latter system is hereafter referred to as the combined heat and power (CHP) system), in the cooling operation mode, the exhaust heat remained and the latent heat removal was insufficient. In this study, the performance of an HDCS was simulated at a humidity ratio of 10 g/kg in conditioned spaces and for an increasing dehumidification capacity of the desiccant rotor. Simulation models of the HDCS linked to the CHP system were based on a transient system simulation tool (TRNSYS). Furthermore, TRNBuild (the TRNSYS Building Model) was used to simulate the three-dimensional structure of cooling spaces and solar lighting conditions. According to the simulation results, when the desiccant capacity increased, the thermal comfort conditions in all three conditioned spaces were sufficiently good. The higher the ambient temperature, the higher the evaporative cooling performance was. The variation in the regeneration heat with the outdoor conditions was the most dominant factor that determined the coefficient of performance (COP). Therefore, the COP was higher under high temperature and dry conditions, resulting in less regeneration heat being required. According to the prediction results, when the dehumidification capacity is sufficiently increased for using more exhaust heat, the overall efficiency of the CHP can be increased while ensuring suitable thermal comfort conditions in the cooling space.

scholarly journals Analytical Investigation of a Novel System for Combined Dew Point Cooling and Water Recovery

2021 ◽  
Vol 11 (4) ◽  
pp. 1481
Author(s):  
Aleksandra Cichoń ◽  
William Worek
Keyword(s):  
Energy Consumption ◽  
Convective Heat Transfer Coefficient ◽  
Specific Energy Consumption ◽  
Analytical Investigation ◽  
Dew Point ◽  
Energy Utilization ◽  
Coefficient Of Performance ◽  
Air Cooling ◽  
Water Recovery ◽  
Utilization Factor

This paper presents the analytical investigation of a novel system for combined Dew Point Cooling and Water Recovery (DPC-WR system). The operating principle of the presented system is to utilize the dew point cooling phenomenon implemented in two stages in order to obtain both air cooling and water recovery. The system performance is described by different indicators, including the coefficient of performance (COP), gained output ratio (GOR), energy utilization factor (EUF), specific energy consumption (SEC) and specific daily water production (SDWP). The performance indicators are calculated for various climatic zones using a validated analytical model based on the convective heat transfer coefficient. By utilizing the dew point cooling phenomenon, it is possible to minimize the heat and electric energy consumption from external sources, which results in the COP and GOR values being an order of magnitude higher than for other cooling and water recovery technologies. The EUF value of the DPC-WR system ranges from 0.76 to 0.96, with an average of 0.90. The SEC value ranges from 0.5 to 2.0 kWh/m3 and the SDWP value ranges from 100 to 600 L/day/(kg/s). In addition, the DPC-WR system is modular, i.e., it can be multiplied as needed to achieve the required cooling or water recovery capacity.

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