Thermal and Optical Analysis of a Stacked Photobioreactor Design

2013 ◽  
Author(s):  
Aadhar Jain ◽  
Erica E. Jung ◽  
Michael Kalontarov ◽  
David Erickson
Keyword(s):  
Thermal Characteristics ◽  
Thermal Conditions ◽  
Close Packing ◽  
Significant Loss ◽  
Design Parameters ◽  
Optical Analysis ◽  
Optimal Range ◽  
Slab Waveguides ◽  
Localized Delivery ◽  
Photobioreactor Design

In this work, we present thermal and optical analysis of a stacked photobioreactor design for growth of fuel producing photosynthetic cyanobacteria to achieve significantly higher volume and energy efficiency as compared to traditional photobioreactor designs. Our photobioreactor design incorporates racks of propagating slab waveguides [1], stacked over each other with spacing of a few hundred microns, in order to optimize light, fluid and gas delivery — the three essential ingredients for cyanobacterial growth — to the cyanobacteria growing in between the racks. The use of propagating slab waveguides provides a mechanism for efficient localized delivery of light to the cyanobacteria. However, it is important to analyze the light distribution of such waveguide systems in the photobioreactors to ensure they always remain within the optimal range for the bacteria. Further, the close packing of cyanobacteria in a closed system raises concerns regarding heat entrapment within the reactor, due to the heat produced as waste by the cyanobacteria. Higher temperatures can lead to a significant loss in efficiency in fuel producing and growth centers of the bacteria. Therefore it is important to design the reactor with appropriate thermal conditions for constraining the temperatures within optimal range for the bacteria. Here we attempt to simulate the thermal characteristics of such a system and estimate the temperature map of the system, and use these to dictate the design parameters and characteristics of the photobioreactor.

scholarly journals Enzymic Approach to Eurythermalism of Alvinella pompejana and Its Episymbionts

2007 ◽  
Vol 74 (3) ◽  
pp. 774-782 ◽  
Author(s):  
Charles K. Lee ◽  
S. Craig Cary ◽  
Alison E. Murray ◽  
Roy M. Daniel
Keyword(s):  
Equilibrium Model ◽  
Enzyme Stability ◽  
Active Form ◽  
Thermal Adaptation ◽  
Thermal Characteristics ◽  
Dorsal Surface ◽  
Thermal Conditions ◽  
Temperature Adaptation ◽  
Model Parameters ◽  
Alvinella Pompejana

ABSTRACT The equilibrium model, which describes the influence of temperature on enzyme activity, has been established as a valid and useful tool for characterizing enzyme eurythermalism and thermophily. By introducing K eq, a temperature-dependent equilibrium constant for the interconversion between Eact, the active form of enzyme, and Einact, a reversibly inactive form of enzyme, the equilibrium model currently provides the most complete description of the enzyme-temperature relationship; its derived parameters are intrinsic and apparently universal and, being derived under reaction conditions, potentially have physiological significance. One of these parameters, T eq, correlates with host growth temperature better than enzyme stability does. The vent-dwelling annelid Alvinella pompejana has been reported as an extremely eurythermal organism, and the symbiotic complex microbial community associated with its dorsal surface is likely to experience similar environmental thermal conditions. The A. pompejana episymbiont community, predominantly composed of epsilonproteobacteria, has been analyzed metagenomically, enabling direct retrieval of genes coding for enzymes suitable for equilibrium model applications. Two such genes, coding for isopropylmalate dehydrogenase and glutamate dehydrogenase, have been isolated from the A. pompejana episymbionts, heterologously expressed, and shown by reverse transcription-quantitative PCR to be actively expressed. The equilibrium model parameters of characterized expression products suggested that enzyme eurythermalism constitutes part of the thermal adaptation strategy employed by the episymbionts. Moreover, the enzymes' thermal characteristics correspond to their predicted physiological roles and the abundance and expression of the corresponding genes. This paper demonstrates the use of the equilibrium model as part of a top-down metagenomic approach to studying temperature adaptation of uncultured organisms.

scholarly journals CONSTRUCTAL THEORY APPLIED TO THE GEOMETRIC OPTIMIZATION OF ELLIPTICAL CAVITIES INTO A SOLID CONDUCTING WALL

2008 ◽  
Vol 7 (2) ◽  
pp. 81
Author(s):  
L. A. O. Rocha ◽  
C. Biserni ◽  
E. Lorenzini
Keyword(s):  
Solid Wall ◽  
Thermal Conditions ◽  
Geometric Optimization ◽  
Constructal Theory ◽  
Design Parameters ◽  
Cavity Volume ◽  
Cavity Shape ◽  
Elliptical Cavity ◽  
Conducting Wall ◽  
Geometrical Shapes

This work reports, according to Bejan’s Constructal theory, the geometric optimization of an elliptical cavity that intrudes into a solid conducting wall. The objective is to minimize the global thermal resistance between the solid and the cavity. There is uniform heat generation on the solid wall. The cavity is optimized for two sets of thermal conditions: isothermal cavity and cavity bathed by a steady stream of fluid. The solid conducting wall is isolated on the external perimeter. The total volume and the elliptical cavity volume are fixed while the geometry of the cavity is free to vary. The results show that the optimized geometrical shapes are relatively robust, i.e., insensitive to changes in some of the design parameters: the cavity shape is optimal when penetrates the conducting wall almost completely.

Analysis of Airfoil Trailing Edge Heat Transfer and Its Significance in Thermal-Mechanical Design and Durability

2005 ◽  
Author(s):  
F. J. Cunha ◽  
M. T. Dahmer ◽  
M. K. Chyu
Keyword(s):  
Mechanical Design ◽  
Thermal Characteristics ◽  
Metal Temperature ◽  
Design Parameters ◽  
Trailing Edge ◽  
Aerodynamic Loss ◽  
Expansion Waves ◽  
Detail Design ◽  
Turbine Airfoils ◽  
High Degree

The trailing edge section of modern high-pressure turbine airfoils is an area that requires a high degree of attention from turbine performance and durability standpoints. Aerodynamic loss near the trailing edge includes expansion waves, normal shocks and wake shedding. Thermal issues associated with trailing edge are also very complex and challenging. To maintain effective cooling ensuring metal temperature below design limit is particularly difficult, as it needs to be implemented in a relatively small area of the airfoil. To date little effort has been devoted to advancing the fundamental understanding of the thermal characteristics in airfoil trailing edge regions. Described in this paper are the procedures leading to closed-form, analytical solutions for temperature profile for four most representative trailing edge configurations. The configurations studied are: (1) solid wedge shape without discharge, (2) wedge with slot discharge, (3) wedge with discrete-hole discharge, and (4) wedge with pressure-side cutback slot discharge. Comparison among these four cases is made primarily in the context of airfoil metal temperature and resulting cooling effectiveness. Further discussed in the paper are the overall and detail design parameters for preferred trailing edge cooling configurations as they affect turbine airfoil performance and durability.

Fundamental Study on Thermal Characteristics of Heat Spreaders

2011 ◽  
Author(s):  
Yasushi Koito ◽  
Yusaku Nonaka ◽  
Toshio Tomimura
Keyword(s):  
Thermal Management ◽  
Theoretical Study ◽  
Thermal Characteristics ◽  
Thermal Design ◽  
Design Parameters ◽  
Heat Spreader ◽  
Fundamental Study ◽  
Discharge Characteristics ◽  
Heat Spreaders ◽  
Large Heat

A heat spreader is one of the solutions for thermal management of electronic and photonic systems. By placing the heat spreader between a small heat source and a large heat sink, the heat flux is spread from the former to the latter, resulting in a lower thermal spreading resistance between them. There are many types of heat spreaders known today having different heat transfer modes, shapes and sizes. This paper describes the theoretical study to present the fundamental data for the rational use and thermal design of heat spreaders. Two-dimensional disk-shaped mathematical model of the heat spreader is constructed, and the dimensionless numerical analysis is performed to investigate the thermal spreading characteristics of the heat spreaders. From the numerical results, the temperature distribution and the heat flow inside the heat spreaders are visualized, and then the effects of design parameters are clarified. The discussion is also made on the discharge characteristics of the heat spreaders. Moreover, a simple equation is proposed to evaluate the heat spreaders.

Analysis of Airfoil Trailing Edge Heat Transfer and Its Significance in Thermal-Mechanical Design and Durability

2005 ◽  
Vol 128 (4) ◽  
pp. 738-746 ◽  
Author(s):  
F. J. Cunha ◽  
M. T. Dahmer ◽  
M. K. Chyu
Keyword(s):  
Mechanical Design ◽  
Thermal Characteristics ◽  
Metal Temperature ◽  
Design Parameters ◽  
Trailing Edge ◽  
Aerodynamic Loss ◽  
Expansion Waves ◽  
Detail Design ◽  
Turbine Airfoils ◽  
High Degree

The trailing edge section of modern high-pressure turbine airfoils is an area that requires a high degree of attention from turbine performance and durability standpoints. Aerodynamic loss near the trailing edge includes expansion waves, normal shocks, and wake shedding. Thermal issues associated with trailing edge are also very complex and challenging. To maintain effective cooling ensuring metal temperature below design limit is particularly difficult, as it needs to be implemented in a relatively small area of the airfoil. To date, little effort has been devoted to advancing the fundamental understanding of the thermal characteristics in airfoil trailing edge regions. Described in this paper are the procedures leading to closed-form, analytical solutions for temperature profile for four most representative trailing edge configurations. The configurations studied are: (1) solid wedge shape without discharge, (2) wedge with slot discharge, (3) wedge with discrete-hole discharge, and (4) wedge with pressure-side cutback slot discharge. Comparison among these four cases is made primarily in the context of airfoil metal temperature and resulting cooling effectiveness. Further discussed in the paper are the overall and detail design parameters for preferred trailing edge cooling configurations as they affect turbine airfoil performance and durability.

scholarly journals Thermographic Analysis of Joints of Supporting Structures

2021 ◽  
Vol 51 (1) ◽  
pp. 94-103
Author(s):  
Laima Skridailaitė ◽  
Loreta Kelpšienė ◽  
Edita Mockienė
Keyword(s):  
Theoretical Calculations ◽  
Thermal Characteristic ◽  
Thermal Characteristics ◽  
Residential Building ◽  
Thermal Conditions ◽  
Energy Class ◽  
Thermographic Analysis ◽  
Residential House ◽  
Building Walls ◽  
The Heat Transfer Coefficient

The external partitions of a building (walls, roof, etc.) in addition to their supporting functions must also ensure an internal microclimate suitable for comfortable human work, recreation and other activities. This article analyzes the thermal characteristics of the external walls of a residential house and thermographically examines the joints of the different structures of the building. Thermographical examination may be performed either passively or actively. In the former case, the object of the examination ir heated up to a given temperature, after which thermographical images of the object are taken and analyzed. In the latter case, thermographical analysis is made of the object in its naturally established thermal conditions. This article examines the thermal characteristics of the partition structures of a residential building. The values of the thermal properties of the materials are taken from the documentation provided by their manufacturers, and in their absence, the data of the technical building regulations is used. Calculated analytically: the wall of the western annex only meets the C energy class requirements, the insulation of the old part of the building raised the heat transfer coefficient of the partition to class A, the thermal characteristic of the eastern annex wall corresponds to the A + energy class. This thermographic examination showed that the facade covered by the fibrous cement siding absorbed less heat compared to the masonry facades. Based on theoretical calculations and the thermographic analysis, it is recommended to additionally insulate the western annex from the inside. If possible, it is also recommended to additionally insulate both facade joints with polyurethane foam and to seal them with waterproofing mastic to prevent the sunrays from reaching the foam.

scholarly journals Strain-induced phase changes within cold basal ice from Taylor Glacier, Antarctica, indicated by textural and gas analyses

2005 ◽  
Vol 51 (175) ◽  
pp. 611-619 ◽  
Author(s):  
Denis Samyn ◽  
Sean J. Fitzsimons ◽  
Reginald D. Lorrain
Keyword(s):  
Thermal Conditions ◽  
Significant Loss ◽  
Phase Changes ◽  
Ductile Deformation ◽  
Geochemical Evolution ◽  
Gas Composition ◽  
Outlet Glacier ◽  
Basal Ice ◽  
Gas Measurements ◽  
Taylor Glacier

AbstractThis paper reports detailed textural and gas measurements conducted in cold basal ice (–17°C from the margin of Taylor Glacier, an outlet glacier of the East Antarctic ice sheet. The analyzed samples were retrieved from a basal ice sequence excavated at the end of a subglacial tunnel dug near the glacier snout. The basal sequence exhibits two contrasting ice facies, defined as the englacial and stratified facies. On the one hand, analysis of ice crystal textures from the basal ice sequence provides evidence for localized ductile deformation, especially within the stratified facies where significant dynamic recrystallization was detected. On the other hand, high-resolution gas analyses reveal that strong changes in gas composition occurred at the structural interfaces of the stratified facies. These gas composition changes are typical of melting–refreezing processes but are not associated with any significant loss of gas volume. Given the specific subglacial thermal conditions at the margin of Taylor Glacier, we interpret this phenomenon as resulting from microscopic phase changes involving selective gas redistribution through the pre-melt phase. It is argued that such processes may play an important role in the post-genetic geochemical evolution of cold debris-laden ice and may be enhanced through intense strain conditions.

Interrelationship between thermal conditions and indoor pollutants in primary schools of Himachal Pradesh

2020 ◽  
pp. 130-137
Author(s):  
Venu Shree ◽  
Bhanu M Marwaha ◽  
Pamita Awasthi
Keyword(s):  
Particulate Matter ◽  
Primary School ◽  
Primary Schools ◽  
Thermal Conditions ◽  
Building Design ◽  
Site Investigation ◽  
Ventilation Rate ◽  
Himachal Pradesh ◽  
Design Parameters ◽  
Indoor Pollutants

Thermal conditions in primary school buildings are very important to ensure healthy aproductive learning environment in primary classrooms. In addition to thermal conditions, poor indoor air quality (IAQ) may decrease productivity, reduced ability of learning, health threats, lack of attentiveness etc. This study is an attempt to discover the interrelationship of the thermal conditions with indoor pollutants in primary schools of Himachal Pradesh, India. The study summarizes the investigation of eight naturally ventilated schools in Hamirpur city of Himachal Pradesh (India). The on-site investigation was performed to monitor the concentration of Carbon monoxide (CO), Carbon dioxide (CO2), Particulate Matter (PM2.5) as indoor pollutants and Indoor Temperature, Humidity and Ventilation rate for thermal conditions. The Higher concentration of indoor Particulate Matter (PM2.5) has found associated with humidity and ventilation rate. However, the CO2 concentration has found directly associated with temperature and ventilation rate. Indoor pollutants were also found associated with some building design parameters of the primary school building. Based on the data analysis, some recommendations are made to reduce the exposure of pollutants to the occupants in the conclusion.

Spent Flow Effects of Multiple Micro-Jet Impingement Cooling Models

2015 ◽  
Author(s):  
Afzal Husain ◽  
Nasser A. Al-Azri ◽  
Abdus Samad ◽  
Sun-Min Kim ◽  
Kwang-Yong Kim
Keyword(s):  
Pressure Drop ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Jet Impingement ◽  
Navier Stokes ◽  
Maximum Temperature ◽  
Design Parameters ◽  
Comparative Performance ◽  
Navier Stokes Equations

The current study investigated comparative performance of wall-confined and unconfined multiple micro-jet impingement heat sink models for electronic cooling applications. The pressure-drop and thermal characteristics were determined for steady incompressible and laminar flow by solving three-dimensional Navier–Stokes equations. Several parallel and staggered micro-jet configurations consisting of a maximum of 16 jet impingements were tested. The effectiveness of various micro-jet configurations, i.e., inline 2×2, 3×3 and 4×4 jets, and staggered 5-jet and 13-jet arrays with nozzle diameters 50, 76, and 100 μm, were analyzed at various flow rates for the maximum temperature-rise, pressure-drop and heat transfer coefficient characteristics. Two design parameters, the ratio of jet diameter to height of the channel and jet distribution, were chosen for comparative performance analysis.

Sign in / Sign up

Export Citation Format

Share Document