scholarly journals Optimal design of mass timber panels as dynamic insulation: simulations of steady and transient heat exchange

2021 ◽  
Vol 2042 (1) ◽  
pp. 012185
Author(s):  
Anna Halepaska ◽  
Salmaan Craig
Keyword(s):  
Heat Exchange ◽  
Optimal Design ◽  
Heat Exchangers ◽  
Building Envelopes ◽  
Dynamic Insulation ◽  
Design Case ◽  
Building Heat ◽  
Mass Timber ◽  
Steady Heat ◽  
Heat Exchange Efficiency

Abstract Mass timber panels could be designed as heat exchangers for use in building envelopes. Fresh air, drawn through geometrically optimized channels in the panel, is pre-tempered with building heat that would otherwise be lost to the exterior via conduction. Recent experiments have shown that timber heat exchanging panels can approach U ~0.1 W/m2K – but there are potential limitations. The sizing correlations which predict panel geometry and steady heat exchange must be numerically calibrated for building-scale contexts, the heat-exchange efficiency must be verified virtually, and practical thresholds for transient response time must be determined. This study uses numerical simulations to investigate these factors for one design ‘case’ of timber panels, and establishes a methodology for studies of further cases.

scholarly journals Mathematical modeling of non-steady heat exchange process in cryogenic coil-wound heat exchangers

2020 ◽  
Vol 324 ◽  
pp. 01009
Author(s):  
Aleksandr A. Vorob’ev ◽  
Dmitriy P. Posanchukov ◽  
Aleksandr A. Kozlov ◽  
Aleksey V. Ivanov
Keyword(s):  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Exchangers ◽  
Exchange Process ◽  
Air Separation ◽  
Separation Unit ◽  
Finned Tubes ◽  
Air Separation Unit ◽  
Heat Exchange Process ◽  
Steady Heat

The paper discusses a dynamic model of coil-wound heat exchanger and its implementation in the MathWorks SimulinkTM computer simulation system. As a simulation object was chosen a coil-wound heat exchanger with wire-finned tubes of a commercial low-capacity air separation unit. The methods for obtaining experimental data has been described, the non-steady heat exchange process has been simulated, and the obtained results have been analyzed.

scholarly journals The Design of Mass Timber Panels as Heat-Exchangers (Dynamic Insulation)

2021 ◽  
Vol 6 ◽  
Author(s):  
Salmaan Craig ◽  
Anna Halepaska ◽  
Katherine Ferguson ◽  
Preston Rains ◽  
Jacob Elbrecht ◽  
...  
Keyword(s):  
Construction Industry ◽  
Heat Exchangers ◽  
Heat Recovery ◽  
Total Heat Transfer ◽  
Exterior Surface ◽  
Thermal Buoyancy ◽  
Forestry Management ◽  
Dynamic Insulation ◽  
Timber Products ◽  
Mass Timber

Mass timber products, together with careful forestry management, could help decarbonize the construction industry. These products must be long-lasting, to safely store atmospheric carbon for decades or centuries, and multi-functional, to displace materials and equipment that are emissions-intensive. This paper shows how to optimize mass timber panels as heat-exchangers, suggesting how to eliminate insulation while simplifying HVAC systems. Test panels measured the heat-exchange in steady and transient conditions, when the ventilation was driven by a fan or by thermal buoyancy. The total heat transfer was predicted accurately by theory in all cases. Further investigation is needed to understand the possible heat-recovery effects at the exterior surface.

scholarly journals Determination of the sediment thickness on the heat-exchange surfaces by free vibration method

2019 ◽  
Vol 124 ◽  
pp. 05069
Author(s):  
E.V. Izmaylova ◽  
E.V. Garnyishova ◽  
R.B. Kazakov ◽  
V.V. Serov
Keyword(s):  
Heat Exchange ◽  
Free Vibration ◽  
Heat Exchangers ◽  
Steel Plates ◽  
Sediment Thickness ◽  
Vibration Method ◽  
Heat Exchange Equipment ◽  
The Heat Transfer Coefficient ◽  
Heat Exchange Efficiency

Sediments on the heat exchangers surfaces reduce the heat transfer coefficient and heat exchange efficiency, and lead to significant energy losses. The paper discusses the method of express control of the sediment thickness on heat-exchange surfaces. The method is based on the analysis of attenuation of free oscillations parameters of the controlled product. Studies were conducted on models of the heat-exchange equipment surface, namely steel plates of 400 mm long, 160 mm wide and 2 mm thick, with different sediments thicknesses of 0, 1.0, 1.5, 2.0, 2.5 mm. The Wilcoxon’s rank sum test was used to determine the dynamics of the spectra changes. Studies have shown that the free vibration method allows one to determine not only the presence of deposits on the heat-exchange surfaces, but also their thicknesses.

scholarly journals Heat exchangers of increased thermal efficiency for power and technological machines: development and research

2018 ◽  
Vol 212 ◽  
pp. 01034
Author(s):  
Nikolai Chernov
Keyword(s):  
Heat Exchange ◽  
Thermal Efficiency ◽  
Heat Exchangers ◽  
New Technologies ◽  
Geometric Parameters ◽  
Thermal Engineering ◽  
Geometrical Parameters ◽  
Research Results ◽  
Wide Range ◽  
Heat Exchange Efficiency

The paper reviews the development and application of new technologies and designs of heat exchangers, as well as the ways to increase the efficiency of heat exchange, with the aim to improve the thermal engineering parameters and performance characteristics of power and process machines and to reduce toxic emissions during their manufacture. Theoretical and practical foundations for increasing the heat exchange efficiency of heat exchangers are also reviewed. The increase in heat exchange efficiency of heat exchangers is achieved by increasing the area of heat exchange surfaces in contact with heat carriers by forming a macrorelief having optimal geometric parameters by finning. A high-efficiency method of machining, deforming cutting (DC), which is based on cutting and bending of the layers of the surface layer of the workpiece metal, providing a wide range of the resulting macrorelief, is chosen for finning the heat exchange surfaces. The paper provides optimal geometric parameters of finning: the fin height (H), the fin pitch (S) and the thickness of the rib (a). The efficiency of the selected geometric parameters is researched and experimentally tested. It has been experimentally established that the finest finning parameters are the minimum fin pitch and the maximum possible fin height. The interrelation is established, and the geometrical parameters of the heat exchange surface processed by the DC method are determined with the operational characteristics of heat exchangers. The greatest thermal efficiency was achieved with a fin pitch of S=1.5 mm, a fin height of h=3 mm, and a thickness of a=0.75 mm. We consider the TA (water oil) design developed by the author to enhance the efficiency of heat exchange. The research results on increasing the efficiency of heat transfer are presented in the paper. The application of the finned coiled tubing heat exchanger developed on the basis of the research results makes it possible to significantly improve the efficiency, reliability, and service life of power and process machines.

scholarly journals Buildings as a Global Carbon Sink? The Design of Mass Timber Panels as Heat-exchangers (Dynamic Insulation)

2020 ◽  
Author(s):  
Salmaan Craig ◽  
Anna Halepaska ◽  
Jacob Elbrecht ◽  
Katherine Ferguson ◽  
Preston Rains ◽  
...  
Keyword(s):  
Construction Industry ◽  
Heat Exchangers ◽  
Carbon Sink ◽  
Exterior Surface ◽  
Thermal Buoyancy ◽  
Forestry Management ◽  
Dynamic Insulation ◽  
Timber Products ◽  
Mass Timber ◽  
Global Carbon

Mass timber products, together with careful forestry management, could help decarbonize the construction industry. These products must be long-lasting, to safely store atmospheric carbon for decades or centuries, and multi-functional, to displace materials and equipment that are emissions-intensive. This paper shows how to optimize mass timber panels as heat-exchangers, suggesting how to eliminate insulation while simplifying HVAC systems. Test panels measured the heat-exchange in steady and transient conditions, when the ventilation was driven by a fan or by thermal buoyancy. The total heatexchange was predicted accurately by theory in all cases. Further investigation is needed to understand the possible heat-recovery effects at the exterior surface.

scholarly journals Analyzing How the ZrO2Far Infrared Material Affects the Performance of Smooth Tube Heat Exchangers

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
T. Y. Chen ◽  
H. P. Cho ◽  
C. S. Jwo ◽  
M. H. Hung ◽  
W. S. Lee
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Heat Exchangers ◽  
Far Infrared ◽  
Smooth Tube ◽  
Ambient Conditions ◽  
Acrylic Paint ◽  
Mixing Method ◽  
Heat Exchange Efficiency

The aim of this study was to investigate the effect of the 100 nm ZrO2far infrared material on the heat exchange efficiency of smooth tube heat exchangers. In the experiments designed for this purpose, the ZrO2powder and water based acrylic paint were mixed separately using a two-step mixing method and the mixture samples were sprayed, respectively, onto heat exchangers for testing their heat exchange efficiency under stable ambient conditions. Results from the experiments showed 31.8% and 21.5% increases in heat transfer in the heat exchanger sprayed with 7.5 wt.% ZrO2powder and with inlet water temperatures at 45°C and 55°C relative to the heat exchanger sprayed with 0 wt.% acrylic paint and 26.4% and 18.9% increases in heat transfer relative to the heat exchanger not sprayed with acrylic paint. The experiments also verified that heat could be transferred through radiation. The additive ZrO2nanopowder in these experiments is proven to be able to improve the efficiency of heat exchangers through radiation, thereby increasing the feasibility of its application in practice.

scholarly journals A Three-Dimensional Numerical and Multi-Objective Optimal Design of Wavy Plate-Fins Heat Exchangers

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 9
Author(s):  
Chao Yu ◽  
Xiangyao Xue ◽  
Kui Shi ◽  
Mingzhen Shao
Keyword(s):  
Heat Exchangers ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Basis Functions ◽  
Approximation Model ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Multi Objective Genetic Algorithm ◽  
Colburn Factor ◽  
Heat Exchange Efficiency

This paper presents a method for optimizing wavy plate-fin heat exchangers accurately and efficiently. It combines CFD simulation, Radical Basis Functions (RBF) with multi-objective optimization to improve the performance. The optimization of the Colburn factor j and the friction coefficient f is regarded as a multi-objective optimization problem, due to the existence of two contradictory goals. The approximation model was obtained by Radical Basis Functions, and the shape of the heat exchanger was optimized by multi-objective genetic algorithm (MOGA). The optimization results showed that j increased by 17.62% and f decreased by 20.76%, indicating that the heat exchange efficiency was significantly enhanced and the fluid structure resistance reduced. Then, from the aspects of field synergy and tubulence energy, the performance advantage of the optimized structure was further confirmed.

Novel Lightweight Metal Foam Heat Exchangers

2001 ◽  
Author(s):  
David P. Haack ◽  
Kenneth R. Butcher ◽  
T. Kim ◽  
T. J. Lu
Keyword(s):  
Heat Exchange ◽  
Pore Size ◽  
Heat Exchangers ◽  
Metal Foam ◽  
Heat Removal ◽  
Random Orientation ◽  
Flow Rates ◽  
Small Pore ◽  
Complex Heat Exchange ◽  
Flow Through

Abstract An overview of open cell metal foam materials with application to advanced heat exchange devices is presented. The metal foam materials considered consist of interconnected cells in a random orientation. Metal foam materials, manufacture and fabrication into complex heat exchange components are described. Experiments with flat foam panels brazed to copper sheets shows increasing heat removal effectiveness with decreasing product pore size at equivalent coolant flow rates. However, the high-pressure drop associated with flow through small pore-size material makes the use of larger pore size material more attractive.

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