A High Performance Semi-Passive Cooling System: The Pulse Thermal Loop

Volume 3 ◽  
2004 ◽  
Author(s):  
Mark M. Weislogel ◽  
Michael A. Bacich
Keyword(s):  
Heat Transport ◽  
High Performance ◽  
Driving Forces ◽  
Cooling System ◽  
Heat Pipes ◽  
Thermal Control ◽  
High Heat ◽  
Transport Systems ◽  
Passive Cooling ◽  
Cooling Systems

Over the past decade, the search for and development of high performance thermal transport systems for a variety of cooling and thermal control applications have intensified. One approach employs a new semi-passive oscillatory heat transport system called the Pulse Thermal Loop (PTL). The PTL, which has only recently begun to be characterized, exploits large pressure differentials from coupled evaporators to force (pulse) fluid through the system. Driving pressures of over 1.8MPa (260psid) have been demonstrated. Other passive cooling systems, such as heat pipes and Loop Heat Pipes, are limited by capillary driving forces, typically less than 70kPa (10psid). Large driving forces can be achieved by a mechanically pumped loop, however, at the expense of increased power consumption, increased total mass, and increased system cost and complexity. The PTL can be configured in either active or semi-passive modes, it can be readily designed for large ∼ O(100kW) or small ∼ O(10W) heat loads, and it has a variety of unique performance characteristics. For low surface tension dielectric fluids such as R-134a, the PTL system has over a 10-fold heat carrying capacity in comparison to high performance heat pipes. Data accumulated thus far demonstrate that the PTL can meet many of the requirements of advanced terrestrial and spacecraft cooling systems: a system that is robust, ‘semi-passive,’ high flux, and offers high heat transport thermal control while remaining flexible in design, potentially lightweight, and cost competitive.

Development of a Gravity-Assist Water Loop Heat Pipe With Flat Evaporator for Waste Heat Removal

2003 ◽  
Author(s):  
Triem T. Hoang ◽  
Tamara A. O’Connell ◽  
C. Thomas Conroy ◽  
Robert G. Mahorter ◽  
John A. Savchik ◽  
...  
Keyword(s):  
Heat Transport ◽  
Waste Heat ◽  
Fluid Management ◽  
Heat Removal ◽  
Heat Pipes ◽  
Pressure Head ◽  
Thermal Control ◽  
Transport Systems ◽  
Gravity Assist ◽  
Long Distance

Use of capillary pumped heat transport devices such as heat pipes, Capillary Pumped Loops (CPLs), and Loop Heat Pipes (LHPs) are being considered for cooling of shipboard electronics. These capillary devices contain no mechanical moving parts to wear out, require no electrical power to operate, and demand virtually no maintenance. Heat pipes have been the mainstay of spacecraft thermal control systems over the past 30 years. However with limited pumping heads, heat pipes were utilized only in a few terrestrial applications. Successful demonstration of much higher pumping capability of CPLs and LHPs in recent years now makes them feasible for ground-based heat transport systems. Fluid management in a gravity environment is also much easier that the traditional design of a CPL/LHP does not really apply to terrestrial systems. In addition, a gravitational pressure head generated by a vertical distance between the condenser and evaporator can assist the capillary pumping to augment the overall pumping capability of the loop. Thus, when properly designed, a gravity-assist CPL/LHP can transport a large amount of waste heat over a long distance for dissipation.

Development of Advanced Cooling Network Systems for Data Centers

2010 ◽  
Author(s):  
Yoshiyuki Abe ◽  
Mayumi Ouchi ◽  
Masato Fukagaya ◽  
Takashi Kitagawa ◽  
Haruhiko Ohta ◽  
...  
Keyword(s):  
High Performance ◽  
Data Centers ◽  
Cooling System ◽  
Heat Pipes ◽  
Energy Utilization ◽  
Liquid Cooling ◽  
Network Systems ◽  
Two Phase ◽  
Cooling Systems ◽  
Development Organization

Energy utilization in data centers, especially cooling systems for server racks, needs extensive improvement. The present authors proposed advanced cooling network systems for data centers, and R & D activities have been conducted under the so-called Green IT Project sponsored by NEDO (New Energy and Industrial Technology Development Organization). In the present concept, CPUs in servers are cooled down by either direct liquid cooling system or heat pipes with liquid cooling systems in the condensation region. The liquid cooling systems are integrated in each server rack and among server racks. A series of studies on both single phase and two phase narrow channel heat exchangers, high performance heat pipes with self-rewetting fluids and nanofluids for heat transfer enhancement are ongoing. In addition, a prototype server rack with the cooling network systems is also under development toward commercial products. This paper reports the updated status of the present R & D.

Electronics Thermal Management Using Advanced Hybrid Two-Phase Loop Technology

2007 ◽  
Author(s):  
Chanwoo Park ◽  
Aparna Vallury ◽  
Jon Zuo ◽  
Jeffrey Perez ◽  
Paul Rogers
Keyword(s):  
Thermal Management ◽  
High Performance ◽  
Cooling System ◽  
Active Flow Control ◽  
Heat Pipes ◽  
High Heat ◽  
Heat Fluxes ◽  
Significant Advance ◽  
Two Phase ◽  
Phase Loop

The paper discusses an advanced Hybrid Two-Phase Loop (HTPL) technology for electronics thermal management. The HTPL combined active mechanical pumping with passive capillary pumping realizing a reliable yet high performance cooling system. The evaporator developed for the HTPL used 3-dimensional metallic wick structures to enhance boiling heat transfer by passive capillary separation of liquid and vapor phases. Through the testing using various prototype hybrid loops, it was demonstrated that the hybrid loops were capable of removing high heat fluxes from multiple heat sources with large surface areas up to 135cm2 and 10kW heat load. Because of the passive capillary phase separation, the hybrid loop operation didn’t require any active flow control of the liquid in the evaporator, even at highly transient and asymmetrical heat inputs between the evaporators. These results represent the significant advance over state-of-the-art heat pipes, loop heat pipes and evaporative spray cooling devices in terms of performance, robustness and simplicity.

Experimental Investigation of Micro/Nano Heat Pipe Wick Structures

2008 ◽  
Author(s):  
H. Peter J. de Bock ◽  
Kripa Varanasi ◽  
Pramod Chamarthy ◽  
Tao Deng ◽  
Ambarish Kulkarni ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
High Performance ◽  
Heat Pipes ◽  
High Heat ◽  
Two Phase ◽  
Wick Structure ◽  
Two Phase Heat Transfer ◽  
Heat Transport Capability ◽  
Transfer Device

The performance of electronic devices is limited by the capability to remove heat from these devices. A heat pipe is a device to facilitate heat transport that has seen increased usage to address this challenge. A heat pipe is a two-phase heat transfer device capable of transporting heat with minimal temperature gradient. An important component of a heat pipe is the wick structure, which transports the condensate from the condenser to the evaporator. The requirements for high heat transport capability and high resilience to external accelerations leads to the necessity of a design trade off in the wick geometry. This makes the wick performance a critical parameter in the design of heat pipes. The present study investigates experimental methods of testing capillary performance of wick structures ranging from micro- to nano-scales. These techniques will facilitate a pathway to the development of nano-engineered wick structures for high performance heat pipes.

Miniature Loop Heat Pipes for Electronic Cooling

2003 ◽  
Author(s):  
Triem T. Hoang ◽  
Tamara A. O’Connell ◽  
Jentung Ku ◽  
C. Dan Butler ◽  
Theodore D. Swanson
Keyword(s):  
Heat Transport ◽  
Electrical Power ◽  
Heat Pipes ◽  
Thermal Control ◽  
Electronic Cooling ◽  
Working Fluid ◽  
Cooling Systems ◽  
Loop Heat Pipes ◽  
Steel Tubing ◽  
Operational Issues

Thermal management of modern electronics has become a problem of significant interest due to the demand for power and reduction in packaging size. Requirements of next-generation microprocessors in terms of power dissipation and heat flux will certainly outgrow the capability of today’s thermal control technology. LHPs, like conventional heat pipes, are capillary pumped heat transport devices. They contain no mechanical moving part to wear out or require electrical power to operate. But unlike heat pipes, LHPs possess much higher heat transport capabilities enabling them to transport large amounts of heat over long distances in small flexible lines for heat rejection. In fact, a miniature ammonia LHP developed for a NASA space program is capable of transporting 60W over a distance of 1 meter in 1/16”O.D. stainless steel tubing. Therefore, miniature LHPs using water as the working fluid are excellent candidates to replace heat pipes as heat transports in electronic cooling systems. However, a number of operational issues regarding system performance, cost, and integration/packaging must be resolved before water LHPs can become a viable option for commercial electronics.

Model Predictive Control of a Pumped Two-Phase Cooling System With Microchannel Heat Exchangers

2018 ◽  
Author(s):  
Oyuna Angatkina ◽  
Andrew Alleyne
Keyword(s):  
Heat Flux ◽  
Model Predictive Control ◽  
Predictive Control ◽  
Heat Exchangers ◽  
Cooling System ◽  
High Heat ◽  
High Heat Flux ◽  
Two Phase ◽  
Cooling Systems ◽  
Two Phase Cooling

Two-phase cooling systems provide a viable technology for high–heat flux rejection in electronic systems. They provide high cooling capacity and uniform surface temperature. However, a major restriction of their application is the critical heat flux condition (CHF). This work presents model predictive control (MPC) design for CHF avoidance in two-phase pump driven cooling systems. The system under study includes multiple microchannel heat exchangers in series. The MPC controller performance is compared to the performance of a baseline PI controller. Simulation results show that while both controllers are able to maintain the two-phase cooling system below CHF, MPC has significant reduction in power consumption compared to the baseline controller.

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.

Novel Fluorescent Visualization Method to Characterize Transport Properties in Micro/Nano Heat Pipe Wick Structures

2009 ◽  
Author(s):  
Pramod Chamarthy ◽  
H. Peter J. de Bock ◽  
Boris Russ ◽  
Shakti Chauhan ◽  
Brian Rush ◽  
...  
Keyword(s):  
Heat Pipe ◽  
High Performance ◽  
Gravitational Force ◽  
Driving Forces ◽  
Electronics Cooling ◽  
Heat Pipes ◽  
High Permeability ◽  
Permeability Characteristics ◽  
Wick Structure ◽  
Initial Results

Heat pipes have been gaining a lot of popularity in electronics cooling applications due to their ease of operation, reliability, and high effective thermal conductivity. An important component of a heat pipe is the wick structure, which transports the condensate from condenser to evaporator. The design of wick structures is complicated by competing requirements to create high capillary driving forces and maintain high permeability. While generating large pore sizes will help achieve high permeability, it will significantly reduce the wick’s capillary performance. This study presents a novel experimental method to simultaneously measure capillary and permeability characteristics of the wick structures using fluorescent visualization. This technique will be used to study the effects of pore size and gravitational force on the flow-related properties of the wick structures. Initial results are presented on wick samples visually characterized from zero to nine g acceleration on a centrifuge. These results will provide a tool to understand the physics involved in transport through porous structures and help in the design of high performance heat pipes.

On Efficient Passive Cooling of Control Rod Drivers

2013 ◽  
Author(s):  
A. N. Gershuni ◽  
A. P. Nishchik ◽  
V. G. Razumovskiy ◽  
I. L. Pioro
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
High Performance ◽  
Cooling System ◽  
Vertical Channel ◽  
Passive Cooling ◽  
Primary Circuit ◽  
Two Phase ◽  
Primary Coolant ◽  
Control Rod

Experimental research of natural convection and the ways of its suppression in an annular vertical channel to simulate the conditions of cooling the control rod drivers of the reactor protection system (RPS) in its so-called wet design, where the drivers are cooled by primary circuit water supplied due to the system that includes branched pipelines, valves, pump, heat exchanger, etc., is reported. Reliability of the drivers depends upon their temperature ensured by operation of an active multi-element cooling system. Its replacement by an available passive cooling system is possible only under significant suppression of natural convection in control rod channel filled with primary coolant. The methods of suppression of natural convection proposed in the work have demonstrated the possibility both of minimization of axial heat transfer and of almost complete elimination of temperature non-uniformity and oscillation inside the channel under the conditions of free travel of moving element (control rod) in it. The obtained results widen the possibilities of substitution of the active systems of cooling the RPS drivers by reliable passive systems, such as high-performance heat-transfer systems of evaporation-condensation type with heat pipes or two-phase thermosyphons as heat-transferring elements.

scholarly journals SISTEM SUBGROUND PASSIVE COOLING PADA GEREJA DI CIBUNUT, KUNINGAN, JAWA BARAT

2021 ◽  
Vol 5 (2) ◽  
pp. 177
Author(s):  
Inggit Musdinar Sayekti Sihing Yang Mawantu ◽  
Sri Kurniasih
Keyword(s):  
Data Collection ◽  
Cooling System ◽  
Passive Cooling ◽  
Cold Climates ◽  
Cooling Systems ◽  
Tropical Climates ◽  
Passive Cooling Systems ◽  
The Tropics ◽  
Passive Cooling System ◽  
The Church

Abstract: Subground passive cooling is a passive cooling technique that is carried out by flowing cold air in the ground into the room. The Pasio Christi Church in Cibunut, Kuningan, West Java was founded in 1965. Then the church implemented a passive cooling subground system through renovations carried out on May 11, 2018. This passive cooling system is usually carried out in areas with subtropical to cold climates, however Cibunut who has a tropical climate tries to implement this system. In fact, there is concern if the system is implemented in the tropics, such as humidity entering the system, causing fungal problems that can have an impact on health. . Therefore this research describes the application of the subground passive cooling system in tropical climates with the following steps: (i) data collection in the form of literature studies, (ii) identification of the subground passive cooling system of Cibunut Church, (iii) elaboration of theory regarding subground passive cooling, (iv) analysis of the application of subground passive cooling of the Cibunut church with the results of theoretical elaboration. This research is expected to be able to contribute in science, especially regarding the application of subground passive cooling systems in tropical climates.Abstrak: Subground passive cooling merupakan teknik pendinginan pasif yang dilakukan dengan mengalirkan udara dingin dalam tanah ke dalam ruangan. Gereja Pasio Christi di Cibunut, Kuningan, Jawa Barat didirikan sejak 1965. Lalu gereja ini menerapkan sistem subground passive cooling melalui renovasi yang dilakukan pada 11 Mei 2018. Sistem pendinginan pasif ini biasanya dilakukan pada wilayah dengan iklim subtropis hingga iklim dingin, namun demikian Cibunut yang beriklim tropis mencoba untuk menerapkan sistem ini. Padahal ada kekawatiran jika sistem ini diterapkan di wilayah tropis, seperti kelembaban yang masuk dalam sistem sehingga muncul permasalahan jamur yang dapat berdampak pada kesehatan. Oleh karena itu pada penelitian ini mendiskripsikan mengenai penerapan sistem subground passive cooling pada wilayah beriklim tropis dengan langkah-langkah sebagai berikut : (i) pengumpulan data dalam bentuk studi literatur, (ii) identifikasi sistem subground passive cooling Gereja Cibunut, (iii) elaborasi teori mengenai subground passive cooling, (iv) analisis penerapan subground passive cooling gereja Cibunut dengan hasil elaborasi teori. Dari penelitian ini diharapkan mampu memberikan sumbangsih dalam keilmuan terutama mengenai penerapan sistem subground passive cooling pada wilayah beriklim tropis.

Sign in / Sign up

Export Citation Format

Share Document