scholarly journals Reducing the Cooling Energy Consumption of Telecom Sites by Liquid Cooling

Proceedings ◽  
2020 ◽  
Vol 58 (1) ◽  
pp. 19
Author(s):  
Jari Huttunen ◽  
Olli Salmela ◽  
Topi Volkov ◽  
Eva Pongrácz
Keyword(s):  
Energy Savings ◽  
Reduction Potential ◽  
Dissipated Energy ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Mobile Data ◽  
Commercial Use ◽  
The Future ◽  
Base Transceiver Station ◽  
Ventilation Duct

The use of mobile data has increased and will continue to increase in the future, because more data is moving to wireless networks such as 5G. Cooling energy need is also expected to increase in indoor telecom rooms, and can be as high as the equipment’s own power consumption. The world’s first liquid Base Transceiver Station (BTS) was adopted into commercial use in 2018, in Helsinki, Finland. Conventional air-cooled BTS hardware was converted into liquid-cooled BTS equipment. Heat from the BTS was pumped out of the site room, and thus ventilation or air conditioning was not needed for the heat load from the BTS. Heat stored in the liquid was released into the ventilation duct of the building, still providing annual cooling energy savings of 70%, when compared to air cooling. In the future, 80% of the total dissipated energy, 13450 kWh/a in total, can potentially be used for heating purposes. In terms of CO2 emissions, adapting liquid cooling showed an 80% reduction potential when compared to air cooling.

A comparative study between air cooling and liquid cooling thermal management systems for a high-energy lithium-ion battery module

2021 ◽  
Vol 198 ◽  
pp. 117503 ◽  
Author(s):  
Mohsen Akbarzadeh ◽  
Theodoros Kalogiannis ◽  
Joris Jaguemont ◽  
Lu Jin ◽  
Hamidreza Behi ◽  
...  
Keyword(s):  
Comparative Study ◽  
Lithium Ion Battery ◽  
Thermal Management ◽  
Lithium Ion ◽  
High Energy ◽  
Management Systems ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Battery Module

scholarly journals Hybrid Battery Thermal Management System in Electrical Vehicles: A Review

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6257
Author(s):  
Chunyu Zhao ◽  
Beile Zhang ◽  
Yuanming Zheng ◽  
Shunyuan Huang ◽  
Tongtong Yan ◽  
...  
Keyword(s):  
Thermal Management ◽  
Management System ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Battery Thermal Management ◽  
Thermal Management System ◽  
Battery Thermal Management System ◽  
Cooling Phase ◽  
Li Ion ◽  
Forced Air

The Li-ion battery is of paramount importance to electric vehicles (EVs). Propelled by the rapid growth of the EV industry, the performance of the battery is continuously improving. However, Li-ion batteries are susceptible to the working temperature and only obtain the optimal performance within an acceptable temperature range. Therefore, a battery thermal management system (BTMS) is required to ensure EVs’ safe operation. There are various basic methods for BTMS, including forced-air cooling, liquid cooling, phase change material (PCM), heat pipe (HP), thermoelectric cooling (TEC), etc. Every method has its unique application condition and characteristic. Furthermore, based on basic BTMS, more hybrid cooling methods adopting different basic methods are being designed to meet EVs’ requirements. In this work, the hybrid BTMS, as a more reliable and environmentally friendly method for the EVs, will be compared with basic BTMS to reveal its advantages and potential. By analyzing its cost, efficiency and other aspects, the evaluation criterion and design suggestions are put forward to guide the future development of BTMS.

New Thermal Management Systems for Data Centers

2012 ◽  
Vol 4 (3) ◽  
Author(s):  
Mayumi Ouchi ◽  
Yoshiyuki Abe ◽  
Masato Fukagaya ◽  
Takashi Kitagawa ◽  
Haruhiko Ohta ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
Single Phase ◽  
Data Centers ◽  
Cooling System ◽  
Heat Pipes ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Two Phase ◽  
Cooling Jacket ◽  
Cooling Methods

Energy consumption in data centers has seen a drastic increase in recent years. In data centers, server racks are cooled down in an indirect way by air-conditioning systems installed to cool the entire server room. This air cooling method is inefficient as information technology (IT) equipment is insufficiently cooled down, whereas the room is overcooled. The development of countermeasures for heat generated by IT equipment is one of the urgent tasks to be accomplished. We, therefore, proposed new liquid cooling systems in which IT equipment is cooled down directly and exhaust heat is not radiated into the server room. Three cooling methods have been developed simultaneously. Two of them involve direct cooling; a cooling jacket is directly attached to the heat source (or CPU in this case) and a single-phase heat exchanger or a two-phase heat exchanger is used as the cooling jacket. The other method involves indirect cooling; heat generated by CPU is transported to the outside of the chassis through flat heat pipes and the condensation sections of the heat pipes are cooled down by coolant with liquid manifold. Verification tests have been conducted by using commercial server racks to which these cooling methods are applied while investigating five R&D components that constitute our liquid cooling systems: the single-phase heat exchanger, the two-phase heat exchanger, high performance flat heat pipes, nanofluid technology, and the plug-in connector. As a result, a 44–53% reduction in energy consumption of cooling facilities with the single-phase cooling system and a 42–50% reduction with the flat heat pipe cooling system were realized compared with conventional air cooling system.

Relative Cooling With Liquid for Gas Turbines: Part I — A Solution for Exceeding 2000 K at Turbine Inlet

2001 ◽  
Author(s):  
Sandu Constantin ◽  
Dan Brasoveanu
Keyword(s):  
Thermal Efficiency ◽  
Gas Turbines ◽  
Cooling System ◽  
Turbine Blades ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Cooling Systems ◽  
Turbine Inlet ◽  
Cooling Methods ◽  
Current Operating

Abstract The thermal efficiency of gas turbines is critically dependent on the temperature of burnt gases at turbine inlet, the higher this temperature the higher the efficiency. Stochiometric combustion would provide maximum efficiency, but in the absence of an internal cooling system, turbine blades cannot tolerate gas temperatures that exceed 1300 K. Therefore, for this temperature, the thermal efficiency of turbine engine is 40% less than theoretical maximum. Conventional air-cooling techniques of turbine blades allow inlet temperatures of about 1500 K on current operating engines yielding thermal efficiency gains of about 6%. New designs, that incorporate advanced air-cooling methods allows inlet temperatures of 1750–1800 K, with a thermal efficiency gain of about 6% relative to current operating engines. This temperature is near the limit allowed by air-cooling systems. Turbine blades can be cooled with air taken from the compressor or with liquid. Cooling systems with air are easier to design but have a relatively low heat transfer capacity and reduce the efficiency of the engine. Some cooling systems with liquid rely on thermal gradients to promote re-circulation from the tip to the root of turbine blades. In this case, the flow and cooling of liquid are restricted. For best results, cooling systems with liquid should use a pump to re-circulate the coolant. In the past, designers tried to place this pump on the engine stator and therefore were unable to avoid high coolant losses because it is impossible to reliably seal the stator-rotor interface. Therefore it was assumed that cooling systems with liquid could not incorporate pumps. This is an unwarranted assumption as shown studying the system in a moving frame of reference that is linked to the rotor. Here is the crucial fact overlooked by previous designers. The relative motion of engine stator with respect to the rotor is sufficient to motivate a cooling pump. Both the pump and heat exchange system that is required to provide rapid cooling of liquid with cold ambient air, could be located within the rotor. Therefore, the entire cooling system can be encapsulated within the rotor and the sealing problem is circumvented. Compared to recent designs that use advanced air-cooling methods, such a liquid cooling system would increase the thermal efficiency by 8%–11% because the temperatures at turbine inlet can reach stoichiometric levels and most of the heat extracted from turbine during cooling is recuperated. The appreciated high reliability of the system will permit a large applicability in aerospace propulsion.

Enabling Thermal Management of High-Powered Server Processors Using Passive Thermosiphon Heat Sink

2019 ◽  
Author(s):  
Devdatta P. Kulkarni ◽  
Priyanka Tunuguntla ◽  
Guixiang Tan ◽  
Casey Carte
Keyword(s):  
Heat Pipe ◽  
High Power ◽  
Heat Sink ◽  
Capital Investment ◽  
Thermal Design ◽  
Heat Sinks ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Two Phase ◽  
Pipe Heat

Abstract In recent years, rapid growth is seen in computer and server processors in terms of thermal design power (TDP) envelope. This is mainly due to increase in processor core count, increase in package thermal resistance, challenges in multi-chip integration and maintaining generational performance CAGR. At the same time, several other platform level components such as PCIe cards, graphics cards, SSDs and high power DIMMs are being added in the same chassis which increases the server level power density. To mitigate cooling challenges of high TDP processors, mainly two cooling technologies are deployed: Liquid cooling and advanced air cooling. To deploy liquid cooling technology for servers in data centers, huge initial capital investment is needed. Hence advanced air-cooling thermal solutions are being sought that can be used to cool higher TDP processors as well as high power non-CPU components using same server level airflow boundary conditions. Current air-cooling solutions like heat pipe heat sinks, vapor chamber heat sinks are limited by the heat transfer area, heat carrying capacity and would need significantly more area to cool higher TDP than they could handle. Passive two-phase thermosiphon (gravity dependent) heat sinks may provide intermediate level cooling between traditional air-cooled heat pipe heat sinks and liquid cooling with higher reliability, lower weight and lower cost of maintenance. This paper illustrates the experimental results of a 2U thermosiphon heat sink used in Intel reference 2U, 2 node system and compare thermal performance using traditional heat sinks solutions. The objective of this study was to showcase the increased cooling capability of the CPU by at least 20% over traditional heat sinks while maintaining cooling capability of high-power non-CPU components such as Intel’s DIMMs. This paper will also describe the methodology that will be used for DIMMs serviceability without removing CPU thermal solution, which is critical requirement from data center use perspective.

A Review of Recent Progress in Aircraft Gun Design as it Affects Installation in Aircraft

1946 ◽  
Vol 50 (432) ◽  
pp. 986-997
Author(s):  
G. F. Wallace
Keyword(s):  
Special Reference ◽  
Air Force ◽  
Recent Progress ◽  
Standard Form ◽  
Air Cooling ◽  
Royal Air Force ◽  
The Future

Experience with the installation of guns in aircraft in recent years suggests that there has been little co-operation between gun designers and aircraft designers. This becomes more apparent as gun calibres increase and if satisfactory fighting aircraft are to be produced in the future, closer co-operation between gun designers and aircraft designers will be necessary. In consequence, a brief review of the progress of gun design in recent years, with special reference to its effect on installation, may be of interest.From 1918 to 1938 the standard guns used in the Royal Air Force were the Lewis gun and Vickers Maxim gun, both Army guns modified for air cooling. The installation of these guns had reached a standard form by 1918 which was adhered to for the best part of 20 years.

scholarly journals Design of an Optimized Thermal Management System for Li-Ion Batteries under Different Discharging Conditions

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5695 ◽  
Author(s):  
Ankur Bhattacharjee ◽  
Rakesh K. Mohanty ◽  
Aritra Ghosh
Keyword(s):  
Thermal Management ◽  
Cooling System ◽  
Peak Temperature ◽  
Air Cooling ◽  
Li Ion Batteries ◽  
Li Ion Battery ◽  
Liquid Cooling ◽  
Thermal Management System ◽  
Li Ion ◽  
Liquid Cooling System

The design of an optimized thermal management system for Li-ion batteries has challenges because of their stringent operating temperature limit and thermal runaway, which may lead to an explosion. In this paper, an optimized cooling system is proposed for kW scale Li-ion battery stack. A comparative study of the existing cooling systems; air cooling and liquid cooling respectively, has been carried out on three cell stack 70Ah LiFePO4 battery at a high discharging rate of 2C. It has been found that the liquid cooling is more efficient than air cooling as the peak temperature of the battery stack gets reduced by 30.62% using air cooling whereas using the liquid cooling method it gets reduced by 38.40%. The performance of the liquid cooling system can further be improved if the contact area between the coolant and battery stack is increased. Therefore, in this work, an immersion-based liquid cooling system has been designed to ensure the maximum heat dissipation. The battery stack having a peak temperature of 49.76 °C at 2C discharging rate is reduced by 44.87% to 27.43 °C after using the immersion-based cooling technique. The proposed thermal management scheme is generalized and thus can be very useful for scalable Li-ion battery storage applications also.

Improvement in Server Compute Performance Using Advanced Air Cooled Thermal Solutions

2017 ◽  
Author(s):  
Devdatta Kulkarni ◽  
Sandeep Ahuja ◽  
Sanjoy Saha
Keyword(s):  
Form Factor ◽  
Boundary Conditions ◽  
High Performance ◽  
Thermal Design ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Increasing Demand ◽  
Performance Computing ◽  
Design Power

Continuously increasing demand for higher compute performance is pushing for improved advanced thermal solutions. In high performance computing (HPC) area, most of the end users deploy some sort of direct or indirect liquid cooling thermal solutions. But for the users who have air cooled data centers and air cooled thermal solutions are challenged to cool next generation higher Thermal Design Power (TDP) processors in the same platform form factor without changing environmental boundary conditions. This paper presents several different advanced air cooled technologies developed to cool high TDP processors in the same form factor and within the same boundary conditions of current generation processor. Comparison of thermal performance using different cooling technologies such as Liquid Assist Air Cooling (LAAC) and Loop Heat Pipe (LHP) are presented in this paper. A case study of Intel’s Knights Landing (KNL) processor is presented to show case the increase in compute performance due to different advanced air cooling technologies.

Numerical Investigation of Heat Transfer and Pressure Loss of Double-Layer Microchannels for Chip Liquid Cooling

2012 ◽  
Author(s):  
Gongnan Xie ◽  
Yanquan Liu ◽  
Bengt Sunden ◽  
Weihong Zhang ◽  
Jun Zhao
Keyword(s):  
Heat Transfer ◽  
Double Layer ◽  
Pressure Loss ◽  
Heat Dissipation ◽  
Thermal Characteristics ◽  
Parallel Flow ◽  
Air Cooling ◽  
Pumping Power ◽  
Liquid Cooling ◽  
Counter Flow

The problem involved in the increase of the chip output power of high-performance integrated electronic devices is the failure of reliability because of excessive thermal loads. This requires advanced cooling methods to manage the increase of the dissipated heat. The traditional air-cooling may not meet the requirements, and therefore a new generation of liquid cooling technology becomes necessary. Various microchannels are widely used to cool the electronic chips by a gas or liquid, but these microchannels are often designed to be single-layer channels. In this paper, the laminar heat transfer and pressure loss in a kind of double-layer microchannel have been investigated numerically. The layouts of parallel-flow and counter-flow for inlet/outlet flow directions are designed and then several sets of inlet flowrates are considered. The simulations show that such a double-layer microchannel can not only reduce the pressure drop effectively but also exhibits better thermal characteristics, and the parallel-flow layout is found to be better for heat dissipation when the pumping power is limited, while the counter-flow layout is better when a high pumping power is provided.

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