Remote Heat Pipe Based Heat Exchanger Performance in Notebook Cooling

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

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

scholarly journals Thermal Resistance of Cascade Heat Pipe as CPU Cooling System to Maintain Safe Temperature for Computer

2021 ◽  
Vol 81 (1) ◽  
pp. 165-173
Author(s):  
Wayan Nata Septiadi ◽  
Fazlur Rahman ◽  
Made Ricki Murti ◽  
Komang Wahyu Tri Prasetia ◽  
Gerardo Janitra Puriadi Putra ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Heat Pipe ◽  
Cooling System ◽  
Processing Unit ◽  
Cooling Systems ◽  
Processor Utilization ◽  
Full Load ◽  
Central Processing ◽  
Small Form Factor ◽  
The Right

Computer will overheat quickly if used in a state of full load continuously. One component on a computer that generates heat is the central processing unit (CPU) which is a key component on a computer where program instructions are processed. One of the right solutions to cool the CPU is the use of heat pipes as cooling system, using several size container, loaded with a special liquid liquid to deliver the heat from the evaporator zone to the other end called condenser zone, but because the heat pipe condenser output temperature is still high therefore a cascade heat pipe was created to lower the output temperature. In this study there are four CPU cooling systems used namely single condenser cascade heat pipe and a double condenser cascade heat pipe, while others two cooling systems as a comparison namely non-cascade heat pipe and non-cascade heat pipe with fan. This study aims to find out the cooling performance of cascade heat pipe as CPU cooling system in a small form factor desktop PC by testing variations in workload, the workload given is idle load (12W) where the processor only runs the operating system without the software load so the processor utilization is only 1% -10%. Next is the medium load (30W) that uses 2 threads with processor utilization of 50% -90%. The last workload is full load (35W) with the number of threads used being 4 with processor utilization of 90% -100%. This research found that the thermal resistance of the cascade heat pipe tended to be higher than that of the non-cascade heat pipe, however the increase that occurred was not too large compared to the resulting performance of 60.2°C in the processor and 40.4°C in the heat sink for the cascade double condenser, the operating temperature of the CPU does not increase significantly as the thermal resistance increases on the cascade heat pipe.

Inlet Air Cooling Applied to Combined Cycle Power Plants: Influence of Site Climate and Thermal Storage Systems

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Nicola Palestra ◽  
Giovanna Barigozzi ◽  
Antonio Perdichizzi
Keyword(s):  
Power Output ◽  
Parametric Analysis ◽  
Power Plants ◽  
Cooling System ◽  
Thermal Storage ◽  
Combined Cycle ◽  
Operating Conditions ◽  
Air Cooling ◽  
Ambient Conditions ◽  
Cooling Systems

The paper presents the results of an investigation on inlet air cooling systems based on cool thermal storage, applied to combined cycle power plants. Such systems provide a significant increase of electric energy production in the peak hours; the charge of the cool thermal storage is performed instead during the night time. The inlet air cooling system also allows the plant to reduce power output dependence on ambient conditions. A 127MW combined cycle power plant operating in the Italian scenario is the object of this investigation. Two different technologies for cool thermal storage have been considered: ice harvester and stratified chilled water. To evaluate the performance of the combined cycle under different operating conditions, inlet cooling systems have been simulated with an in-house developed computational code. An economical analysis has been then performed. Different plant location sites have been considered, with the purpose to weigh up the influence of climatic conditions. Finally, a parametric analysis has been carried out in order to investigate how a variation of the thermal storage size affects the combined cycle performances and the investment profitability. It was found that both cool thermal storage technologies considered perform similarly in terms of gross extra production of energy. Despite this, the ice harvester shows higher parasitic load due to chillers consumptions. Warmer climates of the plant site resulted in a greater increase in the amount of operational hours than power output augmentation; investment profitability is different as well. Results of parametric analysis showed how important the size of inlet cooling storage may be for economical results.

Influence of selected factors on parameters of a cooling system with a Peltier module and forced air flow

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Krzysztof Posobkiewicz ◽  
Krzysztof Górecki
Keyword(s):  
Thermal Resistance ◽  
Heat Sink ◽  
Cooling System ◽  
Heat Sinks ◽  
Cooling Power ◽  
Cooling Systems ◽  
Content Type ◽  
Peltier Module ◽  
Peltier Modules ◽  
Forced Air

Purpose The purpose of this study is to investigate the validation of the usefulness of cooling systems containing Peltier modules for cooling power devices based on measurements of the influence of selected factors on the value of thermal resistance of such a cooling system. Design/methodology/approach A cooling system containing a heat-sink, a Peltier module and a fan was built by the authors and the measurements of temperatures and thermal resistance in various supply conditions of the Peltier module and the fan were carried out and discussed. Findings Conclusions from the research carried out answer the question if the use of Peltier modules in active cooling systems provides any benefits comparing with cooling systems containing just passive heat-sinks or conventional active heat-sinks constructed of a heat-sink and a fan. Research limitations/implications The research carried out is the preliminary stage to asses if a compact thermal model of the investigated cooling system can be formulated. Originality/value In the paper, the original results of measurements and calculations of parameters of a cooling system containing a Peltier module and an active heat-sink are presented and discussed. An influence of power dissipated in the components of the cooling system on its efficiency is investigated.

scholarly journals Physicochemical characteristics of solid particles of contaminants in the coolant of automobile and tractor engines

2021 ◽  
Vol 1 (3) ◽  
pp. 53-61
Author(s):  
S.G. Dragomirov ◽  
◽  
P.Ig. Eydel ◽  
A.Yu. Gamayunov ◽  
M.S. Dragomirov ◽  
...  
Keyword(s):  
High Performance ◽  
Cooling System ◽  
Chemical Elements ◽  
Dissimilar Materials ◽  
Physicochemical Characteristics ◽  
Operating Conditions ◽  
Solid Particles ◽  
Physicochemical Interaction ◽  
Cooling Systems ◽  
Thin Oxide Film

The article describes the results of a study of the physicochemical characteristics of solid particles of contaminants present in the coolant of automobile and tractor engines. The data on the fractional, physical and chemical composition of solid particles of contamination are given. It was established that the generalized reason for the appearance of contaminants of various nature in liquid cooling systems of engines is the physicochemical interaction of the coolant (antifreeze) with different elements and dissimilar materials of the cooling system. The use of absolutely pure coolant in the cooling systems of automobile and tractor engines is practically unrealistic, since there will always be operating conditions that contribute to the formation of contamination. A number of chemical elements (in an amount from 1 to 47% of each element) were found in the composition of solid particles of coolant contaminants: iron Fe, silicon Si, aluminum Al, lead Pb, tin Sn, zinc Zn, calcium Ca, magnesium Mg, copper Cu. In addition, at a level of less than 1.0% (wt.), Such chemical elements as potassium K, sodium Na, titanium Ti, phosphorus P, sulfur S, chromium Cr, molyb-denum Mo, chlorine Cl, iridium Ir, nickel Ni, manganese Mn, etc. were found. The most dangerous contaminants are particles of iron Fe and silicon Si, contained in the coolant in an amount of up to 47 and 37%, respectively, and possessing significant hardness and angularity. The abrasive proper-ties of Fe and Si particles create the danger of removing a thin oxide film on the inner surface of the walls of the cooling radiator channels, leading to their premature destruction. In this regard, it is concluded that high-performance engine coolant filters should be used in automobiles and tractors to remove these contaminants from the flow.

scholarly journals Integration of a Pulsating Heat Pipe in a Flat Plate Heat Sink

2014 ◽  
Author(s):  
Mitchell P. Hoesing ◽  
Gregory J. Michna
Keyword(s):  
Thermal Resistance ◽  
Flat Plate ◽  
Heat Pipe ◽  
Heat Sink ◽  
New Technologies ◽  
Operating Conditions ◽  
Working Fluid ◽  
High Heat Flux ◽  
Pulsating Heat Pipe ◽  
Plate Heat

The ongoing development of faster and smaller electronic components has led to a need for new technologies to effectively dissipate waste thermal energy. The pulsating heat pipe (PHP) shows potential to meet this need, due to its high heat flux capacity, simplicity, and low cost. A 20-turn flat plate PHP was integrated into an aluminum flat plate heat sink with a simulated electronic load. The PHP heat sink used water as the working fluid and had 20 parallel channels with dimensions 2 mm × 2 mm × 119 mm. Experiments were run under various operating conditions, and thermal resistance of the PHP was calculated. The performance enhancement provided by the PHP was assessed by comparing the thermal resistance of the heat sink with no working fluid to that of it charged with water. Uncharged, the PHP was found to have a resistance of 1.97 K/W. Charged to a fill ratio of approximately 75% and oriented vertically, the PHP achieved a resistance of .49 K/W and .53 K/W when the condenser temperature was set to 20°C and 30°C, respectively. When the PHP was tilted to 45° above horizontal the PHP had a resistance of .76 K/W and .59 K/W when the condenser was set 20°C and 30°C, respectively. The PHP greatly improves the heat transfer properties of the heat sink compared to the aluminum plate alone. Additional considerations regarding flat plate PHP design are also presented.

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

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

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

Mass Nature of Heat and Its Application VII: Coupled Heat and Mass Transfer Optimization Based on the Entransy Theory

2010 ◽  
Author(s):  
Qun Chen ◽  
Moran Wang ◽  
Ning Pan ◽  
Zeng-Yuan Guo
Keyword(s):  
Mass Transfer ◽  
Thermal Resistance ◽  
Heat And Mass Transfer ◽  
Cooling System ◽  
Evaporative Cooling ◽  
Entransy Dissipation ◽  
Cooling Systems ◽  
Entransy Theory ◽  
Transfer Processes ◽  
Mass Transfer Processes

Using the analogy between heat and mass transfer processes, the recently developed entransy theory is extended in this paper to tackle the coupled heat and mass transfer processes so as to analyze and optimize the performance of evaporative cooling systems. We first introduce a few new concepts including the moisture entransy, moisture entransy dissipation, and the thermal resistance in terms of the moisture entransy dissipation. Thereinafter, the moisture entransy is employed to describe the endothermic ability of a moist air. The moisture entransy dissipation on the other hand is used to measure the loss of the endothermic ability, i.e. the irreversibility, in the coupled heat and mass transfer processes, which consists of three parts: (1) the sensible heat entransy dissipation, (2) the latent heat entransy dissipation, and (3) the entransy dissipation induced by a temperature potential. And then the new thermal resistance, defined as the moisture entransy dissipation rate divided by the squared refrigerating effect output rate, is recommended as an index to effectively reflect the performance of the evaporative cooling system. Meanwhile, a minimum thermal resistance law for optimizing the evaporative cooling systems is developed. In the end, several direct and indirect evaporative cooling processes are analyzed to illustrate the applications of the proposed concepts.

Transient Performance of Heat Pipes Using Nanofluids

2020 ◽  
Author(s):  
Mahboobe Mahdavi ◽  
Amir Faghri
Keyword(s):  
Numerical Model ◽  
Pressure Drop ◽  
Response Time ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Volume Concentration ◽  
Heat Pipes ◽  
Operating Conditions ◽  
Vapor Flow ◽  
Transient Performance

Abstract In the present works, a comprehensive transient numerical model was developed to evaluate the effect of nanofluid on the transient performance of heat pipes. The numerical model solves for compressible vapor flow, the liquid flow in the wick region, and the energy equations in the vapor, wick and wall. The distinctive feature of the model is that it can uniquely determine the heat pipe operating pressure based on the physical and operating conditions of the system. Three nanoparticle types were considered: Al2O3, CuO, and TiO2. The effects of the concentration of nanoparticles (5%, 10%, 20% and 40%) were investigated on the heat pipe response time, thermal resistance, and pressure drop under various operating conditions. The results showed that the use of nanofluid decreased the response time of the heat pipe by the maximum of 27%. It was also discovered that the thermal resistance decreased significantly with an increase in the volume concentration. A maximum reduction of 84%, 82% and 78% in thermal resistance was obtained for Al2O3, CuO, and TiO2, respectively. In addition, the effect of nanoparticles on the liquid pressure drop highly depends on the nanoparticle type and volume concentration.

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