scholarly journals Heat Treatment and Ventilation Optimization in a Deep Mine

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Xingxin Nie ◽  
Xiaobin Wei ◽  
Xiaochen Li ◽  
Caiwu Lu
Keyword(s):  
High Temperatures ◽  
Mine Water ◽  
Cooling System ◽  
Ventilation System ◽  
Ventilation Network ◽  
Cooling Systems ◽  
Deep Mine ◽  
Working Face ◽  
Deep Pit ◽  
Western Area

In order to address the issue of high temperatures and thermal damages in deep mines, the factors causing downhole heat damage at high temperatures were analyzed, the mine ventilation system was optimized and rebuilt, and a cooling system was established. The proposed cooling system uses mine water as the cooling source, and its features are based on the analysis of traditional cooling systems. The current ventilation system in the 1118 m deep pit of the Jinqu Gold Mine was evaluated, and the ventilation network, ventilation equipment, and ventilation structures near the underground working face were optimized. The low-temperature mine water stored in the middle section of the mine at 640 m depth was used as the cooling source, and a cooling system was established near the 440 m deep middle return well to alleviate the high-temperature and high-humidity conditions of the 280 m deep middle-western area. The results show that the effective air volume in the west wing at 280 m was 3.0 m3/s, the operating ambient temperature was 27.6°C, the relative humidity was reduced to 76%, and the temperature was reduced by 5-6°C after the optimization of the system.

An application of thermal exermal analysis to the development of mine cooling systems

2002 ◽  
Vol 216 (8) ◽  
pp. 845-857 ◽  
Author(s):  
C T Twort ◽  
I S Lowndes ◽  
S J Pickering
Keyword(s):  
Water Distribution ◽  
Cooling System ◽  
Ventilation System ◽  
Cost Effective ◽  
Mine Ventilation ◽  
Distribution Networks ◽  
Ventilation Network ◽  
Generic Model ◽  
Cooling Systems ◽  
Chilled Water

The extraction of minerals and coal at greater depth, employing higher-powered machinery to improve production levels, imposes an increased burden on the ability of a ventilation system to maintain an acceptable mine climate. Hence, mechanical mine cooling systems are often adopted, which can be expensive both in terms of their associated capital and operating costs. Consequently, in order to optimize the costs it is essential to provide the mine operator with a method with which to determine the most cost effective and efficient mine cooling system. The following paper overviews the development of a novel approach to the energy analysis of mine cooling systems using the concepts of thermal exergy analysis. Generic model mine ventilation networks are constructed and the subsurface environments of these mine networks predicted. Models of various cooling system methods are developed and applied to control the underground climate within these mine networks to within pre-set climatic limits. The exergy transfers that are produced by the application of the different cooling methods are compared using performance indices. Models to represent chilled water distribution networks, used to supply the air coolers within the various cooling systems, are designed and balanced. The results of the exergy analyses applied to the operation of the various chilled water pipe networks are discussed and used to assess the exergetic performance of the application of each cooling system to the mine ventilation network.

scholarly journals Effects of Cooling Systems on Greenhouse Microclimate and Cucumber Growth under Mediterranean Climatic Conditions

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 300 ◽  
Author(s):  
Georgios Nikolaou ◽  
Damianos Neocleous ◽  
Nikolaos Katsoulas ◽  
Constantinos Kittas
Keyword(s):  
Vapor Pressure Deficit ◽  
Cooling System ◽  
Ventilation System ◽  
Climatic Conditions ◽  
Irrigation Regime ◽  
Crop Water ◽  
Water Losses ◽  
Cooling Systems ◽  
Cropping Seasons ◽  
The Impact

Two experiments were conducted in different cropping seasons under Mediterranean climatic conditions to investigate the impact of two cooling systems (fan-pad evaporative as opposed to fan ventilation) on greenhouse microclimate and soilless cucumber growth. The second objective of the experiment was to determine the most appropriate irrigation regime (between 0.24 and 0.32 L m−2) in relation to crop water uptake and greenhouse fertigation effluents. The use of a fan ventilation system enhanced the vapor pressure deficit; thus, the crop transpiration improved by 60% in relation to the transpiration rates of plants grown under the fan-pad system. Higher transpiration rates alleviated the heat load as the external–inside greenhouse air differences declined from 6.2 °C to 3 °C. The leaf–air temperature differential indicated that plants were not facing any water stress conditions for both cooling systems tested; however, fan ventilation reduced drainage emissions outflows (95% decrease) compared with evaporative cooling. Results also demonstrated that an irrigation regime of 0.24 L m−2 can be applied successfully in soilless cucumber crops, keeping the drainage to a minimum (20% of the nutrient solution supply). These results suggest that fan ventilation cooling system in conjugation with an appropriate irrigation regime prevents overheating and minimizes the nutrient and water losses in spring-grown soilless cucumber crops in Mediterranean greenhouses without compromising yield.

Long axis heat distribution in a tunnel-ventilated broiler house equipped with an evaporative pad cooling system

2009 ◽  
Vol 49 (12) ◽  
pp. 1125 ◽  
Author(s):  
M. Dağtekin ◽  
C. Karaca ◽  
Y. Yildiz
Keyword(s):  
High Temperatures ◽  
Air Temperature ◽  
Egg Production ◽  
Cooling System ◽  
Heat Distribution ◽  
Exit Point ◽  
Cooling Efficiency ◽  
Cooling Systems ◽  
Southern Turkey ◽  
Broiler House

Chicken meat and egg production in the Çukurova region of Southern Turkey shows enormous potential for growth. However, high temperatures in summer pose serious difficulties for these types of production. Evaporative pad cooling systems have been used to minimise rises in temperature and are commonly used in poultry houses in this region. The change of air temperature from the entry point to the system through the pads, to the exit point of the broiler house was investigated in this study. Experiments were carried out in a tunnel-ventilated broiler house in the Çukurova region. The broiler house has the capacity to house 15 000 chicks with a floor area of 70 by 12 m. In this experiment, the broiler house incorporated 15-cm-thick cellulose-based pads. Results obtained in August–September 2007 revealed a cooling efficiency of 69.35%, a 5.19°C decrease from the outside air temperature after passing through the pads, and a 1.52°C increase in air temperature at the exit point, which was located at the end of the broiler house.

scholarly journals A PCM based cooling system for office buildings: a state of the art review

2019 ◽  
Vol 111 ◽  
pp. 01026
Author(s):  
Evdoxia Paroutoglou ◽  
Alireza Afshari ◽  
Niels Chr. Bergsøe ◽  
Peter Fojan ◽  
Göran Hultmark
Keyword(s):  
Renewable Energy ◽  
Energy Storage ◽  
Thermal Comfort ◽  
Energy Use ◽  
State Of The Art ◽  
Cooling System ◽  
Renewable Energy Sources ◽  
Ventilation System ◽  
High Energy ◽  
Cooling Systems

Cooling of air in buildings has a significant effect on thermal comfort and, consequently, productivity of office occupants. This study presents a state of the art review of energy efficient cooling systems that will provide occupants in buildings with satisfying thermal comfort. Using high-temperature cooling systems combined with renewable energy sources increases the energy efficiency in buildings. Latent heat thermal energy storage (LHTES) using Phase Change Materials (PCM) is a renewable energy source implemented in space cooling applications due to its high energy storage density. Since the share of commercial buildings in need of cooling is increasing, there is a need for developing new technical solutions in order to reduce the energy use without compromising thermal comfort. To this end, a proposed ventilation system, preliminarily analyzed in this paper, is expected to reduce further the energy use. The ventilation system is composed of an air handling unit, a 2-pipe active chilled beam system, and a cooling system including a LHTES using PCM. Few researchers have investigated chilled water air-conditioning systems that integrate a LHTES using PCM. In this review, function characteristics, possibilities and limitations of existing systems are discussed.

scholarly journals Defining of the required parameters of the main fans on the ventilation shaft for the target model of the hard coal mine Y in connection with its decommissioning

2021 ◽  
Vol 906 (1) ◽  
pp. 012052
Author(s):  
Piotr Mocek
Keyword(s):  
Coal Mine ◽  
Mine Water ◽  
Ventilation System ◽  
Drainage System ◽  
Ventilation Network ◽  
Hard Coal ◽  
Target Model ◽  
Ventilation Shaft ◽  
Water Pumping ◽  
Hard Coal Mining

Abstract The article presents the results of the analysis and calculations of the ventilation network of the decommissioned hard coal mine Y for the model of its target operation. After the end of hard coal mining and the liquidation of most of the mining excavations, the former Y hard coal mine will become an element of the drainage system and a protection for other, still active mining plants. In order for the Y excavation to be transformed into a mine water pumping station, its ventilation system should be rebuilt, and new parameters of the main fan should be determined for a smaller network of mining excavations. For this purpose, using the AERO-2016D program by POK “Zachód” Spółka z o.o., the parameters of the ventilation network were simulated in the target model of mine Y after the liquidation of the “Southern” shaft and mining excavations at levels 530m and 660m. The results of the simulation made it possible to select the optimal main fans for the target model of the transformed mine Y.

scholarly journals Efficiency of cooling systems in broiler houses during hot days

2021 ◽  
Vol 51 (8) ◽  
Author(s):  
Maurício Portella dos Santos ◽  
Matheus Deniz ◽  
Karolini Tenffen de Sousa ◽  
Daniela Regina Klein ◽  
Tatiane Branco ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Spatial Distribution ◽  
Environmental Variables ◽  
Cooling System ◽  
Ventilation System ◽  
Cooling Efficiency ◽  
Cooling Systems ◽  
Hot Days ◽  
Evaporative Cooling System ◽  
Broiler House

ABSTRACT: This study evaluated: (1) the vulnerability of broiler houses with different cooling systems, and (2) the spatial distribution of environmental variables during hot days. Four potentially vulnerable commercial broiler houses in southern Brazil were selected according to the following parameters: absence or presence of different cooling systems, broilers older than 28 days, and outside air dry-bulb temperature over 30°C. Broiler house vulnerability was classified according to the cooling and mechanical ventilation system: cellulose pad cooling (CPC), sprinkling (SPK), fogging (FOG), and mechanical ventilation without evaporative cooling system (VTL). The air dry-bulb temperature (Tdb, °C) and relative humidity (RH, %) were recorded every 10 min. For each broiler house, we evaluated: (1) relative cooling efficiency (RCE) and (2) inside spatial distribution of microclimate variables using a geostatistical technique. The CPC and SPK did not differ (P<0.05) in RCE (81.6% and 80.7%, respectively), but both differed from FOG (23.8%) and VLT (1.87%) systems. The highest variations in indoor Tdb were recorded in the FOG (7 °C), followed by the SPK (4 °C) and CPC (3 °C). In the CPC, there was an increase in RH from the middle to the end of the broiler house near the exhaust fans. In conclusion, the relative cooling efficiency and the inside spatial distributions of environmental variables in the broiler houses were influenced by the existing cooling system.

Assessment of thermal behavior of a cooling system to reduce thermal fatigue cracks in aluminum injection molds

2020 ◽  
pp. 75-86
Author(s):  
Sergio Antonio Camargo ◽  
Lauro Correa Romeiro ◽  
Carlos Alberto Mendes Moraes
Keyword(s):  
Thermal Fatigue ◽  
Cooling System ◽  
Fatigue Cracks ◽  
Cooling Water ◽  
Thermal Conditions ◽  
Thermal Gradients ◽  
Ansys Software ◽  
Cooling Systems ◽  
Thermal Fatigue Cracks ◽  
Number Of Cycles

The present article aimed to test changes in cooling water temperatures of males, present in aluminum injection molds, to reduce failures due to thermal fatigue. In order to carry out this work, cooling systems were studied, including their geometries, thermal gradients and the expected theoretical durability in relation to fatigue failure. The cooling system tests were developed with the aid of simulations in the ANSYS software and with fatigue calculations, using the method of Goodman. The study of the cooling system included its geometries, flow and temperature of this fluid. The results pointed to a significant increase in fatigue life of the mold component for the thermal conditions that were proposed, with a significant increase in the number of cycles, to happen failures due to thermal fatigue.

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.

Perimeter Cooling Unit and Localized Row-Based Cooling Unit Transient Air Flow Effects Modeling and Characterization in Data Centers

2015 ◽  
Author(s):  
Tianyi Gao ◽  
James Geer ◽  
Bahgat G. Sammakia ◽  
Russell Tipton ◽  
Mark Seymour
Keyword(s):  
Thermal Management ◽  
Data Center ◽  
Data Centers ◽  
Cooling System ◽  
Air Flow ◽  
Cooling Systems ◽  
Dynamic Thermal Management ◽  
Hybrid Cooling ◽  
Cooling Unit ◽  
Cooling Air

Cooling power constitutes a large portion of the total electrical power consumption in data centers. Approximately 25%∼40% of the electricity used within a production data center is consumed by the cooling system. Improving the cooling energy efficiency has attracted a great deal of research attention. Many strategies have been proposed for cutting the data center energy costs. One of the effective strategies for increasing the cooling efficiency is using dynamic thermal management. Another effective strategy is placing cooling devices (heat exchangers) closer to the source of heat. This is the basic design principle of many hybrid cooling systems and liquid cooling systems for data centers. Dynamic thermal management of data centers is a huge challenge, due to the fact that data centers are operated under complex dynamic conditions, even during normal operating conditions. In addition, hybrid cooling systems for data centers introduce additional localized cooling devices, such as in row cooling units and overhead coolers, which significantly increase the complexity of dynamic thermal management. Therefore, it is of paramount importance to characterize the dynamic responses of data centers under variations from different cooling units, such as cooling air flow rate variations. In this study, a detailed computational analysis of an in row cooler based hybrid cooled data center is conducted using a commercially available computational fluid dynamics (CFD) code. A representative CFD model for a raised floor data center with cold aisle-hot aisle arrangement fashion is developed. The hybrid cooling system is designed using perimeter CRAH units and localized in row cooling units. The CRAH unit supplies centralized cooling air to the under floor plenum, and the cooling air enters the cold aisle through perforated tiles. The in row cooling unit is located on the raised floor between the server racks. It supplies the cooling air directly to the cold aisle, and intakes hot air from the back of the racks (hot aisle). Therefore, two different cooling air sources are supplied to the cold aisle, but the ways they are delivered to the cold aisle are different. Several modeling cases are designed to study the transient effects of variations in the flow rates of the two cooling air sources. The server power and the cooling air flow variation combination scenarios are also modeled and studied. The detailed impacts of each modeling case on the rack inlet air temperature and cold aisle air flow distribution are studied. The results presented in this work provide an understanding of the effects of air flow variations on the thermal performance of data centers. The results and corresponding analysis is used for improving the running efficiency of this type of raised floor hybrid data centers using CRAH and IRC units.

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.

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