scholarly journals Design and Analysis of Radiant Ceiling Cooling Panels for Classroom

2021 ◽  
Vol 9 (VI) ◽  
pp. 580-583
Author(s):  
Ms. Amruta Mohite
Keyword(s):  
Heat Transfer ◽  
Cooling System ◽  
Water Flow Rate ◽  
Specific Area ◽  
Paper Analysis ◽  
Cfd Analysis ◽  
Cooling Systems ◽  
Environment Friendly ◽  
Radiant Cooling ◽  
Study Case

In this study, radiant cooling panel is designed for a classroom. An arrangement is made such that the panels cover 70% of ceiling area. For study case a classroom is considered which need 27 such panels for covering 70% of area. The arrangement of panels, water flow rate, required temperature and amount of heat transfer taking place through panels is discussed in the paper. A cooling system is selected for maintaining the desired water temperature. Comparison is done between the cooling systems and the user can use any of them according to the requirements and cost. This system does not use any refrigerant hence it is environment friendly and can add a considerable solution to maintain temperature of a specific area. CFD analysis of the panel shows that adequate heat transfer takes place between panel and the room, this validates the design. When 15 ºC water is given as inlet to the panel, we get 22 ºC water as output at outlet of panel. In this paper, analysis is done for single panel same can be done for entire arrangement of panel structure.

On Development of a Semi-Mechanistic Wall Boiling Model

2013 ◽  
Author(s):  
Saurish Das ◽  
Hemant Punekar
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Thermal Stresses ◽  
Cooling System ◽  
Nucleate Boiling ◽  
Heat Fluxes ◽  
Working Fluid ◽  
Wall Heat Transfer ◽  
Cooling Systems ◽  
Transfer Phenomenon

In modern cooling systems the requirement of higher performance demands highest possible heat transfer rates, which can be achieved by controlled nucleate boiling. Boiling based cooling systems are gaining attention in several engineering applications as a potential replacement of conventional single-phase cooling system. Although the controlled nucleate boiling enhances the heat transfer, uncontrolled boiling may lead to Dry Out situation, adversely affecting the cooling performance and may also cause mechanical damage due to high thermal stresses. Designing boiling based cooling systems requires a modeling approach based on detailed fundamental understanding of this complex two-phase heat and mass transfer phenomenon. Such models can help analyze different cooling systems, detect potential design flaws and carry out design optimization. In the present work a new semi-mechanistic wall boiling model is developed within commercial CFD solver ANSYS FLUENT. A phase change mechanism and wall heat transfer augmentation due to nucleate boiling are implemented in mixture multiphase flow framework. The phase change phenomenon is modeled using mechanistic evaporation-condensation model. Enhancement of wall heat transfer due to nucleate boiling is captured using 1D empirical correlation, modified for 3D CFD environment. A new method is proposed to calculate the local suppression of nucleate boiling based on the flow velocity, and hence this model can be applied to any complex shaped coolant passage. For different wall superheat, the wall heat fluxes predicted by the present model are validated against experimental data, in which 50-50 volume mixture of aqueous ethylene glycol (a typical anti-freeze coolant mixture) is used as working fluid. The validation study is performed in ducts of different sizes and shapes with different inlet velocities, inlet sub-cooling and operating pressures. The results are in good agreement with the experiments. This model is applied to a typical automobile Exhaust Gas Recirculation (EGR) system to study boiling heat transfer phenomenon and the results are presented.

Conjugate Heat Transfer Methodology for Thermal Design and Verification of Gas Turbine Cooled Components

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Lorenzo Winchler ◽  
Antonio Andreini ◽  
Bruno Facchini ◽  
Luca Andrei ◽  
Alessio Bonini ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Conjugate Heat Transfer ◽  
Cooling System ◽  
Measurement Data ◽  
Thermal Design ◽  
Heat Transfer Analysis ◽  
Internal Cooling ◽  
Cfd Analysis ◽  
Continuous Increase

Gas turbine design has been characterized over the years by a continuous increase of the maximum cycle temperature, justified by a corresponding increase of cycle efficiency and power output. In such way, turbine components heat load management has become a compulsory activity, and then, a reliable procedure to evaluate the blades and vanes metal temperatures is, nowadays, a crucial aspect for a safe components design. In the framework of the design and validation process of high pressure turbine cooled components of the BHGE NovaLTTM 16 gas turbine, a decoupled methodology for conjugate heat transfer prediction has been applied and validated against measurement data. The procedure consists of a conjugate heat transfer analysis in which the internal cooling system (for both airfoils and platforms) is modeled by an in-house one-dimensional thermo-fluid network solver, the external heat loads and pressure distribution are evaluated through 3D computational fluid dynamics (CFD) analysis and the heat conduction in the solid is carried out through a 3D finite element method (FEM) solution. Film cooling effect has been treated by means of a dedicated CFD analysis, implementing a source term approach. Predicted metal temperatures are finally compared with measurements from an extensive test campaign of the engine in order to validate the presented procedure.

scholarly journals Laboratory tests of a prototypical user-centric radiant cooling solution

2021 ◽  
Vol 2069 (1) ◽  
pp. 012122
Author(s):  
H Teufl ◽  
M Schuss ◽  
A Mahdavi
Keyword(s):  
Surface Temperature ◽  
Cooling System ◽  
Dew Point ◽  
Cooling Systems ◽  
Efficient Operation ◽  
Radiant Cooling ◽  
Close Proximity ◽  
Free Cooling ◽  
Condensed Water ◽  
Vapour Condensation

Abstract Radiant cooling systems are being increasingly promoted because of their energy efficient operation as well as their potential to improve occupants’ thermal comfort due to a draft-free cooling process. This paper focuses on a specific radiant cooling approach, which was introduced in previous contributions. This approach involves the positioning of relatively small-sized vertical radiant panels in the close proximity to occupants. Furthermore, the panels incorporate drainage systems or collection elements to accommodate, if needed, water vapour condensation. Consequently, the surface temperature of the radiant panels does not need to stay above the dew point temperature. We present the outcome of a preliminary experimental investigation of such a personal radiant cooling system. In this context, prototypical radiant panels were installed in a laboratory and multiple experiments were conducted. The uniformity level of the panels’ surface temperature distribution was documented. Moreover, near-panel air flow velocities were measured at several positions. Likewise, the formation of condensed water on panels was observed for different panel surface temperatures, room temperatures, and room humidity levels. The results of the preliminary laboratory investigation do not point to any risk of draft or turbulence discomfort.

COMPUTER SIMULATION OF TRANSFER PROCESSES IN MICROJET BURNER DEVICES WITH SPECIAL COOLING SYSTEMS

2017 ◽  
Author(s):  
Nataliia Fialko ◽  
Viktor Prokopov ◽  
Sergiy Alioshko ◽  
Julii Sherenkovskiy ◽  
Nataliia Meranova ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Computer Simulation ◽  
Cooling System ◽  
Cooling Systems ◽  
Transfer Processes ◽  
Flow And Heat Transfer ◽  
Inner Surface ◽  
Air Blowing

The analysis of efficiency of cooling system of the microjet stabilization burner devices is performed. The features of the flow and heat transfer in cooling systems with air blowing of the inner surface of flame stabilizator and with flat and circular impact jets are studied.

Towards a Technoeconomic Framework for Estimating Cost-Performance Tradeoffs for Power Plants Incorporating Transformative Dry-Cooling Technologies

2016 ◽  
Author(s):  
Geoffrey Short ◽  
Addison K. Stark ◽  
Daniel Matuszak ◽  
James F. Klausner
Keyword(s):  
Heat Transfer ◽  
Power Plant ◽  
Fresh Water ◽  
Power Plants ◽  
Cooling System ◽  
Combined Cycle ◽  
Cooling Systems ◽  
Natural Gas Combined Cycle ◽  
Evaporative Cooling System ◽  
Dry Cooling

Fresh water withdrawal for thermoelectric power generation in the U.S. is approximately 139 billion gallons per day (BGD), or 41% of total fresh water draw, making it the largest single use of fresh water in the U.S. Of the fresh water withdrawn for the power generation sector, 4.3 BGD is dissipated to the atmosphere by cooling towers and spray ponds. Dry-cooled power plants are attractive and sometimes necessary because they avoid significant withdrawal and consumption of freshwater resources that could otherwise be used for other purposes. This could become even more important when considering the potential effects of climate change (1). Additional benefits of dry-cooling include power plant site flexibility, reduced risk of water scarcity, and faster permitting (reducing project development time and cost). However, dry-cooling systems are known to be more costly and larger than their wet-cooling counterparts. Additionally, without the benefit of additional latent heat transfer through evaporation, the Rankine cycle condensing (cold) temperature for dry-cooling is typically higher than that for wet-cooling, affecting the efficiency of power production and the resultant levelized cost of electricity (LCOE). The Advanced Research Projects Agency - Energy (ARPA-E) has developed a technoeconomic analysis (TEA) model for the development of indirect dry-cooling systems employing steam condensation within a natural gas combined cycle power plant. The TEA model has been used to inform the Advanced Research in Dry-Cooling (ARID) Program on the performance metrics needed to achieve an economical dry-cooling technology. In order to assess the relationship between air-cooled heat exchanger (ACHX) performance, including air side heat transfer coefficient and pressure drop, and power plant economics, ARPA-E has employed a modified version of the National Energy Technology Laboratory (NETL) model of a 550 MW natural gas combined cycle (NGCC) plant employing an evaporative cooling system. The evaporative cooling system, including associated balance of system costs, was replaced with a thermodynamic model for an ACHX with the desired improved heat transfer performance and supplemental cooling and storage systems. Monte Carlo simulation determined an optimal ACHX geometry and associated ACHX cost. Allowing for an increase in LCOE of 5%, the maximum allowable additional cost of the supplemental cooling system was determined as a function of the degree of cooling of the working fluid required. This paper describes the methodologies employed in the TEA, details the results, and includes related models as supplemental material, while providing insight on how the open source tool might be used for thermal management innovation.

scholarly journals Controlling the Distribution of Cold Water in Air Cooling Systems of Underground Mines

2016 ◽  
Vol 61 (4) ◽  
pp. 793-807 ◽  
Author(s):  
Nikodem Szlązak ◽  
Dariusz Obracaj ◽  
Justyna Swolkień ◽  
Kazimierz Piergies
Keyword(s):  
Automatic Control ◽  
Water Flow ◽  
Flow Rate ◽  
Cold Water ◽  
Cooling System ◽  
Water Flow Rate ◽  
Underground Mines ◽  
Air Cooling ◽  
Cooling Systems ◽  
Pipeline Network

Abstract In Polish underground mines in which excavations are subjected to high heat load, central and group cooling systems based on indirect cooling units are implemented. Chilled water, referred to as cold water and produced in chillers, is distributed through a pipeline network to air coolers located in mining and development districts. The coolers are often moved to other locations and the pipeline network undergoes constant modification. In such a system, parameters of cold water in different branches of the pipeline network need to be controlled. The article presents the principles for controlling the cooling capacity of air coolers installed in an underground mine. Also, the authors propose automatic control of water flow rate in underground pipeline network and in particular coolers, depending on the temporary cooling load in the system. The principles of such a system, controlling cold water distribution, and the functions of its individual components are described. Finally, an example of an automatic control of water flow rate in a central cooling system currently implemented in a mine is presented.

scholarly journals Hydrogen Containing Nanofluids in the Spark Engine’s Cylinder Head Cooling System

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 59
Author(s):  
Alexander Balitskii ◽  
Myroslav Kindrachuk ◽  
Dmytro Volchenko ◽  
Karol F. Abramek ◽  
Olexiy Balitskii ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Cylinder Head ◽  
Base Fluid ◽  
Mass Concentration ◽  
Thermal Conductivity Coefficient ◽  
Cooling System ◽  
Cooling Systems ◽  
Engine Cooling ◽  
Head Cooling

The article is devoted to the following issues: boiling of fluid in the cooling jacket of the engine cylinder head; agents that influenced the thermal conductivity coefficient of nanofluids; behavior of nanoparticles and devices with nanoparticles in the engine’s cylinder head cooling system. The permissible temperature level of internal combustion engines is ensured by intensification of heat transfer in cooling systems due to the change of coolants with “light” and “heavy” nanoparticles. It was established that the introduction of “light” nanoparticles of aluminum oxide into the water in a mass concentration of 0.75% led to an increase in its thermal conductivity coefficient by 60% compared to the base fluid at a coolant temperature of 90 °C, which corresponds to the operating temperature of the engine cooling systems. At the indicated temperature, the base fluid has a thermal conductivity coefficient of 0.545 W/(m °С), for nanofluid with particles its value was 0.872 . At the same time, a positive change in the parameters of the nanofluid in the engine cooling system was noted: the average movement speed increased from 0.2 to 2.0 m/s; the average temperature is in the range of 60–90 °C; heat flux density 2 × 102–2 × 106 ; heat transfer coefficient 150–1000 . Growth of the thermal conductivity coefficient of the cooling nanofluid was achieved. This increase is determined by the change in the mass concentration of aluminum oxide nanoparticles in the base fluid. This will make it possible to create coolants with such thermophysical characteristics that are required to ensure intensive heat transfer in cooling systems of engines with various capacities.

scholarly journals Análisis térmico e hidráulico de diferentes geometrías de tubos para mejorar el desempeño de un radiador de automóvil

2020 ◽  
pp. 13-23
Author(s):  
José Luis ZUÑIGA-CERROBLANCO ◽  
Juan Gregorio HORTELANO-CAPETILLO ◽  
Juan Carlos COLLAZO-BARRIENTOS ◽  
Abel HERNANDEZ-GUERRERO
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Automotive Industry ◽  
New Technologies ◽  
Cooling System ◽  
Numerical Study ◽  
Hydraulic Performance ◽  
Cooling Systems ◽  
Cooling Fluid ◽  
Nusselt Numbers

Nowadays the automotive industry requires more powerful and compact engines, which demand that the cooling systems must be improved using new technologies to attend the aim to maintain the engine working at optimum temperature, the cooling system must be adjusted to the dimensions and weight set to avoid the increase of fuel expense. In the present work a numerical study to analyze the thermal and hydraulic performance of a car radiator is carried out. The research focuses on analyzing different geometries for the tubes that make up the radiator, inside of tubes a mixture of 80% water and 20% ethylene glycol is used as the cooling fluid. On the results the global Nusselt numbers for the different geometries, as well as the total pressure drop along the radiator tube are reported. A comparison of the thermal and hydraulic performance for the different geometries analyzed is made. From the results the best geometry to increase heat transfer is chosen, as well as the geometry with the best balance between entropy generation due to heat transfer and pressure drop is chosen.

Conjugate Heat Transfer Methodology for Thermal Design and Verification of Gas Turbine Cooled Components

2018 ◽  
Author(s):  
Lorenzo Winchler ◽  
Antonio Andreini ◽  
Bruno Facchini ◽  
Luca Andrei ◽  
Alessio Bonini ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Conjugate Heat Transfer ◽  
Cooling System ◽  
Measurement Data ◽  
Thermal Design ◽  
Heat Transfer Analysis ◽  
Cfd Analysis ◽  
3D Fem ◽  
Continuous Increase

Gas turbine design has been characterized over the years by a continuous increase of the maximum cycle temperature, justified by a corresponding increase of cycle efficiency and power output. In such way turbine components heat load management has become a compulsory activity and then, a reliable procedure to evaluate the blades and vanes metal temperatures, is, nowadays, a crucial aspect for a safe components design. In the framework of the design and validation process of HPT (High Pressure Turbine) cooled components of the BHGE NovaLT™ 16 gas turbine, a decoupled methodology for conjugate heat transfer prediction has been applied and validated against measurement data. The procedure consists of a conjugate heat transfer analysis in which the internal cooling system (for both airfoils and platforms) is modeled by an in-house one-dimensional thermo-fluid network solver, the external heat loads and pressure distribution are evaluated through 3D CFD analysis and the heat conduction in the solid is carried out through a 3D FEM solution. Film cooling effect has been treated by means of a dedicated CFD analysis, implementing a source term approach. Predicted metal temperatures are finally compared with measurements from an extensive test campaign of the engine, in order to validate the presented procedure.

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