Study on the Installed Position Determination Method of the Air Condensers in High Temperature Mine

2014 ◽  
Vol 1065-1069 ◽  
pp. 2129-2132
Author(s):  
Ping Chen ◽  
Fang Fang Li ◽  
Yu Tian Li
Keyword(s):  
High Temperature ◽  
High Efficiency ◽  
Cooling System ◽  
Great Influence ◽  
Air Cooling ◽  
Determination Method ◽  
Coal Face ◽  
Position Determination ◽  
Efficiency And Effectiveness ◽  
The Ideal

Mine cooling system plays an important role in the high temperature mine. The installed position of the air condensers in the intake airway has great influence on the cooling efficiency and effectiveness of coal face. According to the concept of the air cooling length, we mainly study the effective installation position of the mine air condensers in the intake airway and put forward the installed position determination method of more groups of air condensers. Through the average calculation method, the ideal installed position of the air condensers is determined. Thus the efficiency of the mine cooling system is improved, and the safety and high efficiency of the mine production is ensured.

Performance Evaluation of DRACS System for FHTR and Time Assessment of Operation Procedure

2013 ◽  
Author(s):  
Junya Nakata ◽  
Mikihiro Wakui ◽  
Michitsugu Mori ◽  
Hiroto Sakashita ◽  
Charles Forsberg
Keyword(s):  
Performance Evaluation ◽  
High Temperature ◽  
Cooling System ◽  
Heat Removal ◽  
Severe Accident ◽  
Air Cooling ◽  
Fluoride Salt ◽  
Nuclear Power Reactor ◽  
Decay Heat ◽  
Operation Procedure

The Fluoride-salt-cooled High-temperature Reactor (FHR) is a new concept of nuclear power reactor being investigated mainly in U.S. and China. The coolant is a liquid salt with a melting point of about 460°C and a boiling point of over 1400°C. As the baseline decay heat removal system, a passive Direct Reactor Air Cooling System (DRACS) is utilized. Though DRACS system has been developed in Sodium Fast reactors (SFR), there are some differences between both. For example, the system in FHR must decrease heat removal when temperatures are low to avoid freezing of the salt and blocking the flow of liquid. Therefore, considering its characteristics, a numerical investigation of DRACS system is needed to evaluate whether FHR has proper ability to remove decay heat and to be robust for a long-time cooling operation after even a severe accident. Furthermore, in addition to its performance evaluation, it is required to make up the operation plan of FHR considering features of this system. It is highly important, with the view of avoiding severe accident, to determine by when the system should be started up. In both countries mentioned above, Fluoride-salt-cooled High-temperature Test Reactor (FHTR) is currently in progress to build. Reviewing its design and system is a crucial step needed to develop the FHR technology. In this research, a performance of DRACS system under some thermal-hydraulic basic events was evaluated by numerical simulation. This paper also suggested the adequate operation procedure suitable for FHTR to avoid a severe accident.

scholarly journals Comparative response on the accumulation of inorganic phosphate in leaf of Basella alba to low and high temperature

2014 ◽  
Vol 20 ◽  
pp. 83-90
Author(s):  
Md Shahidul Haque ◽  
Md Monirul Islam ◽  
Tanzima Yeasmin
Keyword(s):  
High Temperature ◽  
Inorganic Phosphate ◽  
Metabolic Regulation ◽  
Room Temperature ◽  
Prolonged Exposure ◽  
Cooling System ◽  
Air Cooling ◽  
Water Control ◽  
Basella Alba ◽  
Short Term Exposure

Context: Basella alba is a green vegetable and grows in both winter and summer; however the temperature sensitivity on metabolic regulation in this species is not clarified. Objective: To find the role of low and high temperature induced regulation of metabolic functions particularly alteration and accumulation of inorganic phosphate in leaf. Materials and Methods: Plants grown in pot were exposed to cold (8°C) for 24h, 48h and 72h periods and the respective controls were kept in ambient room temperature for the above mentioned time. For high temperature induced plants, they were exposed to 45°C with full aeration along with sufficient water. Control pot was used similarly in room temperature; however, the temperature was maintained 30°C by using air cooling system (AC). Results: Low temperature causes the higher inorganic phosphate level in leaf and was increased by 33.6%, 34.7% and 62.8% respectively when compared to the respective controls. Therefore, it is assumed that short term exposure has mild effect on phosphate accumulation in leaf; conversely as the time extended, the synthesis assumed to be higher and increased time dependently. Similarly, the inorganic phosphate concentrations were increased by 27.8%, 37.5% and 74.9% respectively whenever the plants were exposed to high temperature (45°C). Taken together, a faster increase in accumulation of phosphate in leaf was mediated by high temperature for prolonged exposure. Conclusion: The plants exposed to both abiotic stresses cause the release of inorganic phosphate which may participate in the survival of the species in the adverse environment DOI: http://dx.doi.org/10.3329/jbs.v20i0.17719 J. bio-sci.  20:  83-90, 2012

Design of High Efficiency Aggregate Air Cooling System

2017 ◽  
Author(s):  
Malik I. Alamayreh ◽  
Tareq Barham ◽  
Nabeel Abu Shaban ◽  
Abdulla N. Olimat
Keyword(s):  
High Efficiency ◽  
Cooling System ◽  
Air Cooling ◽  
Air Cooling System

Thermal Modeling and Heat Management of Supercapacitor Modules by High Velocity Impinging Fan Flow

2011 ◽  
Author(s):  
Xinqiang Xu ◽  
Bahgat G. Sammakia ◽  
Bruce T. Murray ◽  
DaeYoung Jung ◽  
Thor Eilertsen
Keyword(s):  
Reynolds Number ◽  
Forced Convection ◽  
High Power ◽  
High Velocity ◽  
High Efficiency ◽  
Cooling System ◽  
Turbulent Transport ◽  
Air Cooling ◽  
Power Requirement ◽  
Convection Cooling

Supercapacitors are a strong candidate for high-power applications such as electric/hybrid vehicles due to their high power densities and high efficiency. In these applications, supercapacitors are used in large stacks (modules) to provide the peak-power requirement. They are subject to heavy duty cycling conditions, which results in significant heat generation inside each cell. Under such conditions, natural convection air cooling is found to be an ineffective method for removing heat from the supercapacitor modules. Therefore, utilizing an appropriate forced convection cooling system becomes necessary for the lifetime and performance of supercapacitor modules. The objective of this paper is to study the cooling of supercapacitor modules under high velocity impinging fan flow. A three-dimensional computational model was developed using the commercial FEM software package COMSOL. The κ-ε two equation turbulence model is employed to account for turbulent transport. The supercapacitor module studied in this paper was composed of 18 cells, which were connected in series. The parameters studied include the Reynolds number of the impinging flow, the spacing between cells and the impingement distance. The results show how the forced convection cooling varies with the Reynolds number and that the Nusselt number increases with the Reynolds number. In addition, the variation of the temperature profile within the module with the spacing arrangement between cells was investigated.

scholarly journals ОХОЛОДЖЕННЯ ПОВІТРЯ НА ВХОДІ ГОЛОВНОГО СУДНОВОГО ДВИГУНА АБСОРБЦІЙНОЮ БРОМИСТОЛІТІЄВОЮ ХОЛОДИЛЬНОЮ МАШИНОЮ В ТРОПІЧНИХ УМОВАХ

2020 ◽  
pp. 18-23
Author(s):  
Роман Миколайович Радченко ◽  
Дмитро Вікторович Коновалов ◽  
Максим Андрійович Пирисунько ◽  
Чжан Цян ◽  
Луо Зевей
Keyword(s):  
Air Temperature ◽  
High Efficiency ◽  
Waste Heat ◽  
Cooling System ◽  
Ambient Air ◽  
Climatic Conditions ◽  
Air Cooling ◽  
Exhaust Gas ◽  
Low Speed ◽  
Speed Engine

The efficiency of air cooling at the inlet of the main low speed engine of a transport vessel during operation in tropical climatic conditions on the Shanghai-Karachi-Shanghai route was analyzed. The peculiarity of the tropical climate is the high relative humidity of the air at the same time its high temperatures, and hence the increased thermal load on the cooling system, which requires efficient transformation of the waste heat into the cold in the case of the use of waste heat recovery refrigeration machines. The cooling of the air at the inlet of the low speed engine by absorption lithium bromide chillers, which are characterized by high efficiency of transformation of waste heat into cold – by high coefficients of performance, is investigated. A schematic-construction solution of the air cooling system at the inlet of the ship's main engine using the heat of exhaust gases by an absorption chiller is proposed and analyzed. With this the cooling potential of the inlet air cooling from the current ambient air temperature to 15 ° C and the corresponding heat consumption for the operation of the adsorption chiller, on the one hand, was compared with the available exhaust gas heat potential, on the other hand. The effect of using the exhaust gas heat to cool the air at the inlet of the engine has been analyzed taking into account the changing climatic conditions during the voyage. Enhancement of fuel efficiency of the ship's engine by reducing the inlet air temperature were evaluated by current values of the reduction in specific and total fuel consumption. It is shown that due to the high efficiency of heat conversion in absorption chillers (high coefficients of performance 0.7…0.8), a significant amount of excessive exhaust gas heat over the heat required to cool the ambient air at the inlet of the engine to 15 ° C, which reaches almost half of the available exhaust gas heat during the Shanghai-Karachi-Shanghai route. This reveals the possibility of additional cooling a scavenge air too with almost double fuel economy due to the cooling of all cycle air of the low speed engine, including the air at the inlet.

Development of Inherently Safe Technologies for Large Scale BWRs: (4) Hydrogen Explosion Prevention System Using SiC Fuel Claddings

2014 ◽  
Author(s):  
Ryo Ishibashi ◽  
Tomohiko Ikegawa ◽  
Kenji Noshita ◽  
Kazuaki Kitou ◽  
Mamoru Kamoshida
Keyword(s):  
High Temperature ◽  
Hydrogen Generation ◽  
Cooling System ◽  
Hydrogen Gas ◽  
Metallic Layer ◽  
Normal Operation ◽  
Air Cooling ◽  
Composite Substrate ◽  
Prevention System ◽  
High Temperature Steam

In the aftermath of the lessons learned from the Fukushima Daiichi nuclear accident, we have been developing the following various safe technologies for boiling water reactors (BWRs), including a passive water-cooling system, an infinite-time air-cooling system, a hydrogen explosion prevention system, and an operation support system for reactor accidents. One of inherently safe technologies currently under development is a system to prevent hydrogen explosion during severe accidents (SAs). This hydrogen explosion prevention system consists of a high-temperature resistant fuel cladding of silicon carbide (SiC), and a passive autocatalytic recombiner (PAR). Replacing the zircaloy (Zry) claddings currently used in LWRs with the SiC claddings decreases the hydrogen generation and thus decreases the risk of hydrogen leakage from a primary containment vessel (PCV) to a reactor building (R/B) such as an operation floor. The PAR recombines the leaked hydrogen gas so as to maintain the hydrogen concentration at less than the explosion limit of 4 % in the R/B. The advantages of using SiC claddings in the system were examined through experiments and SA analysis. Results of steam oxidation tests confirmed that SiC was estimated to show 2 to 3 orders of magnitude lower hydrogen generation rates during oxidation in a high temperature steam environment than Zry. Results of SA analysis showed that the total amount of hydrogen generation from fuels was reduced to one fifth or less. Calculation also showed that the lower heat of the oxidation reaction of SiC moderated the steep generation with the temperature increase. We expected this moderated steep generation to reduce the pressure increase in the PCV as well as prevent excess amounts of leaked hydrogen from hydrogen disposal rate capacity using PARs. The SiC cladding under consideration consists of an inner metallic layer, a SiC/SiC composite substrate, and an outer environment barrier coating (EBC). A thin inner metallic layer in combination with a SiC/SiC composite substrate functions as a barrier for fission products. EBC is introduced to have both corrosion resistance in high temperature water environments during normal operation and oxidation resistance in high temperature steam environments during SA. Further reduction of the hydrogen generation rate in high temperature steam by improving the EBC is expected to decrease the total amount of hydrogen generation even more.

An Estimation of the Performance Limits of Dry Cooling on Trough-Type Solar Thermal Plants

2008 ◽  
Author(s):  
Huifang Deng ◽  
Robert F. Boehm
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Cooling System ◽  
Low Cost ◽  
Performance Limits ◽  
Cooling Systems ◽  
Solar Power Plants ◽  
Solar Resource ◽  
Dry Cooling ◽  
The Ideal

The southwestern US is an ideal location for solar power plants due to its abundant solar resource, while there is a difficulty in implementing wet cooling systems due to the shortage of water in this region. Dry cooling could be an excellent solution for this, if it could achieve a high efficiency and low cost as wet cooling. Some dry cooling systems are currently in operation, and investigations of their performance have been reported in the literature. This paper looks into the limits to the power production implicit in dry cooling, assuming that improvements might be made to the system components. Use of higher performance heat transfer surfaces is one such possible improvement. We have developed a model of a fairly typical, but simplified, solar trough plant, and simulated thermodynamic performance of this with the software Gatecycle. We have examined the power generation and cycle efficiency of the plant for the Las Vegas vicinity with conventional wet cooling and conventional dry cooling cases considered separately using this software. TMY2 data are used for this location for this purpose. Similarly, the same studies are carried out for “ideal” cooling systems as a comparison. We assumed that in the ideal dry cooling system, the condensing temperature is the ambient dry bulb temperature, and in the ideal wet cooling system, it is the ambient wet bulb temperature. It turned out that the ideal dry cooling system would significantly outperform the conventional wet cooling system, indicating the possibility of the dry cooling system being able to achieve increased performance levels with component improvements.

Design of Passive Two-Phase Thermosyphons for Server Cooling

2019 ◽  
Author(s):  
Raffaele L. Amalfi ◽  
Jackson B. Marcinichen ◽  
John R. Thome ◽  
Filippo Cataldo
Keyword(s):  
Energy Consumption ◽  
Total Energy ◽  
Energy Efficient ◽  
High Efficiency ◽  
Cooling System ◽  
Inlet Temperature ◽  
Air Cooling ◽  
Annual Growth Rate ◽  
Total Energy Consumption ◽  
Two Phase

Abstract The main objective of this paper is to utilize an improved version of the simulator presented at InterPACK 2017 to design a thermosyphon system for energy-efficient heat removal from 2-U servers used in high-power datacenters. Currently, between 25% and 45% of the total energy consumption of a datacenter (this number does not include the energy required to drive the fans at the server-level) is dedicated to cooling, and with a predicted annual growth rate of about 15% (or higher) coupled with the plan of building numerous new datacenters to handle the “big data” storage and processing demands of emerging 5G networks, artificial intelligence, electrical vehicles, etc., the development of novel, high efficiency cooling technologies becomes extremely important for curbing the use of energy in datacenters. Notably, going from air cooling to two-phase cooling, not only enables the possibility to handle the ever higher heat fluxes and heat loads of new servers, but it also provides an energy-efficient solution to be implemented for all servers of a datacenter to reduce the total energy consumption of the entire cooling system. In that light, a pseudo-chip with a footprint area of 4 × 4 cm2 and a maximum power dissipation of 300 W (corresponding heat flux of about 19 W/cm2), will be assumed as a target design for our novel thermosyphon-based cooling system. The simulator will be first validated against an independent database and then used to find the optimal design of the chip’s thermosyphon. The results demonstrate the capability of this simulator to model all of the thermosyphon’s components (evaporator, condenser, riser and downcomer) together with overall thermal performance and creation of operational maps. Additionally, the simulator is used here to design two types of passive two-phase systems, an air- and a liquid-cooled thermosyphon, which will be compared in terms of thermal-hydraulic performance. Finally, the simulator will be used to perform a sensitivity analysis on the secondary coolant side conditions (inlet temperature and mass flow rate) to evaluate their effect on the system performance.

System Simulation of an Elastocaloric Heating and Cooling Device Based on SMA

2020 ◽  
Author(s):  
Felix Welsch ◽  
Susanne-Marie Kirsch ◽  
Nicolas Michaelis ◽  
Michele Mandolino ◽  
Andreas Schütze ◽  
...  
Keyword(s):  
High Efficiency ◽  
Cooling System ◽  
Coefficient Of Performance ◽  
System Level ◽  
Air Cooling ◽  
Heating And Cooling ◽  
Work Input ◽  
Air Cooling System ◽  
Level Model ◽  
Latent Heats

Abstract Elastocaloric (EC) cooling uses solid-state NiTi-based shape memory alloy (SMA) as a non-volatile cooling medium and enables a novel environment-friendly cooling technology. Due to the high specific latent heats activated by mechanical loading/unloading, substantial temperature changes are generated in the material. Accompanied by a small required work input, a high coefficient of performance is achievable. Recently, a fully functional and illustrative continuous operating elastocaloric air cooling system based on SMA was developed and realized. To assist the design process of an optimized device with given performance and efficiency requirements, a fully coupled thermo-mechanical system-level model of the multi-wire cooling unit was developed and implemented in MATLAB. The resulting compact simulation tool is qualified for massively parallel computation, which allows fast and comprehensive parameter studies. In this work, the influence of different SMA diameters, rotation frequencies, and airflow rates is investigated. The results are analyzed to find the suited parameter for high efficiency (COP) and temperature span.

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