The Experts below are selected from a list of 17952 Experts worldwide ranked by ideXlab platform
M. Beer - One of the best experts on this subject based on the ideXlab platform.
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the comparative field performance study of heat pipe evacuated tube collectors with standard design manifold header and parallel flow manifold header based on the metal foam structural element
Solar Energy, 2015Co-Authors: R. Rybár, M. BeerAbstract:Abstract The paper deals with an experimental thermal performance comparison of standard design heat pipe evacuated tube collector and collector with parallel flow manifold header with metal foam structural element which was developed by authors in their previous work. The used data were obtained during experimental simultaneous operation of two interconnected solar systems at the Centre of Renewable Energy Sources, Kosice, Slovakia during the months of April and May in various weather and climatic conditions. Manifold header with metal foam structural element partially eliminates deficiencies of standard design manifold headers by changing of heat transfer Medium Stream conducting to each condenser, reducing the internal fluid volume and introducing of new structural element to manifold header design – heat exchange chamber made of metal foam which increases the heat exchange surface of condenser. Presented data consist of a selection from all measurements taken during experimental operation, when solar collector with manifold header based on metal foam showed a performance increase around 25%, and reduced thermal inertia of the solar collector at operation with changing intensity of solar insolation, which leads to an overall improvement in function of the solar system.
R. Rybár - One of the best experts on this subject based on the ideXlab platform.
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the comparative field performance study of heat pipe evacuated tube collectors with standard design manifold header and parallel flow manifold header based on the metal foam structural element
Solar Energy, 2015Co-Authors: R. Rybár, M. BeerAbstract:Abstract The paper deals with an experimental thermal performance comparison of standard design heat pipe evacuated tube collector and collector with parallel flow manifold header with metal foam structural element which was developed by authors in their previous work. The used data were obtained during experimental simultaneous operation of two interconnected solar systems at the Centre of Renewable Energy Sources, Kosice, Slovakia during the months of April and May in various weather and climatic conditions. Manifold header with metal foam structural element partially eliminates deficiencies of standard design manifold headers by changing of heat transfer Medium Stream conducting to each condenser, reducing the internal fluid volume and introducing of new structural element to manifold header design – heat exchange chamber made of metal foam which increases the heat exchange surface of condenser. Presented data consist of a selection from all measurements taken during experimental operation, when solar collector with manifold header based on metal foam showed a performance increase around 25%, and reduced thermal inertia of the solar collector at operation with changing intensity of solar insolation, which leads to an overall improvement in function of the solar system.
Diego A. Riveros‐iregui - One of the best experts on this subject based on the ideXlab platform.
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Spatiotemporal variability of gas transfer velocity in a tropical high‐elevation Stream using two independent methods
'Wiley', 2021Co-Authors: Keridwen M. Whitmore, Nehemiah Stewart, Andrea C. Encalada, Esteban Suárez, Diego A. Riveros‐ireguiAbstract:Abstract Streams in high‐elevation tropical ecosystems known as páramos may be significant sources of carbon dioxide (CO2) to the atmosphere by transforming terrestrial carbon to gaseous CO2. Studies of these environments are scarce, and estimates of CO2 fluxes are poorly constrained. In this study, we use two independent methods for measuring gas transfer velocity (k), a critical variable in the estimation of CO2 evasion and other biogeochemical processes. The first method, kinematic k600 (k600‐K), is derived from an empirical relationship between temperature‐adjusted k (k600) and the physical characteristics of the Stream. The second method, measured k600 (k600‐M), estimates gas transfer velocity in the Stream by in situ measurements of dissolved CO2 (pCO2) and CO2 evasion to the atmosphere, adjusting for temperature. Measurements were collected throughout a 5‐week period during the wet season of a peatland‐Stream transition within a páramo ecosystem located above 4000 m in elevation in northeastern Ecuador. We characterized the spatial heterogeneity of the 250‐m reach on five occasions, and both methods showed a wide range of variability in k600 at small spatial scales. Values of k600‐K ranged from 7.42 to 330 m/d (mean = 116 ± 95.1 m/d), whereas values of k600‐M ranged from 23.5 to 444 m/d (mean = 121 ± 127 m/d). Temporal variability in k600 was driven by increases in Stream discharge caused by rain events, whereas spatial variability was driven by channel morphology, including Stream width and slope. The two methods were in good agreement (less than 16% difference) at high and Medium Stream discharge (above 7.0 L/s). However, the two methods considerably differed from one another (up to 73% difference) at low Stream discharge (below 7.0 L/s, which represents 60% of the observations collected). Our study provides the first estimates of k600 values in a high‐elevation tropical catchment across steep environmental gradients and highlights the combined effects of hydrology and Stream morphology in co‐regulating gas transfer velocities in páramo Streams
Diego Riveros-iregui Author) - One of the best experts on this subject based on the ideXlab platform.
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Spatiotemporal Variability of Gas Transfer Velocity in a Tropical High-Elevation Stream Using Two Independent Methods
2021Co-Authors: Whitmore Keridwen, Diego Riveros-iregui Author)Abstract:*** This work was funded by the National Science Foundation under award 1847331: Streams in high-elevation tropical ecosystems known as páramos may be significant sources of carbon dioxide (CO2) to the atmosphere by transforming terrestrial carbon to gaseous CO2. Studies of these environments are scarce and estimates of CO2 fluxed are poorly constrained. In this study, we use two independent methods for measuring gas transfer velocity (k), a critical variable in the estimation of CO2 evasion and other biogeochemical processes. The first method, ‘Kinematic k600’ (k600-K), is derived from an empirical relationship between temperature-adjusted k (k600) and the physical characteristics of the Stream. The second method, ‘Measured k600’ (k600-M), estimates gas transfer velocity in the Stream by in situ measurements of dissolved CO2 (pCO2) and CO2 evasion to the atmosphere, adjusting for temperature. Measurements were collected throughout a 5-week period during the wet season of a peatland-Stream transition within a páramo ecosystem located above 4,000m in elevation in northeastern Ecuador. We characterized the spatial heterogeneity of the 250-m reach on five occasions, and both methods showed a wide range of variability in k600 at small spatial scales. Values of k600-K ranged from 7.42 to 330 m d-1 (mean =116 ± 95.1 m d-1), whereas values of k600-M ranged from 23.5 to 444 m d-1 (mean = 121 ± 127 m d-1). Temporal variability in k600 was driven by increases in Stream discharge caused by rain events, whereas spatial variability was driven by channel morphology, including Stream width and slope. The two methods were in good agreement (less than 16% difference) at high and Medium Stream discharge (above 7.0 L s-1). However, the two methods considerably differed from one another (up to 73% difference) at low Stream discharge (below 7.0 L s-1). Our study provides the first estimates of k600 values in a high elevation tropical catchment across steep environmental gradients and highlights the combined effects of hydrology and Stream morphology in coregulating gas transfer velocities in páramo Streams
Keridwen M. Whitmore - One of the best experts on this subject based on the ideXlab platform.
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Spatiotemporal variability of gas transfer velocity in a tropical high‐elevation Stream using two independent methods
'Wiley', 2021Co-Authors: Keridwen M. Whitmore, Nehemiah Stewart, Andrea C. Encalada, Esteban Suárez, Diego A. Riveros‐ireguiAbstract:Abstract Streams in high‐elevation tropical ecosystems known as páramos may be significant sources of carbon dioxide (CO2) to the atmosphere by transforming terrestrial carbon to gaseous CO2. Studies of these environments are scarce, and estimates of CO2 fluxes are poorly constrained. In this study, we use two independent methods for measuring gas transfer velocity (k), a critical variable in the estimation of CO2 evasion and other biogeochemical processes. The first method, kinematic k600 (k600‐K), is derived from an empirical relationship between temperature‐adjusted k (k600) and the physical characteristics of the Stream. The second method, measured k600 (k600‐M), estimates gas transfer velocity in the Stream by in situ measurements of dissolved CO2 (pCO2) and CO2 evasion to the atmosphere, adjusting for temperature. Measurements were collected throughout a 5‐week period during the wet season of a peatland‐Stream transition within a páramo ecosystem located above 4000 m in elevation in northeastern Ecuador. We characterized the spatial heterogeneity of the 250‐m reach on five occasions, and both methods showed a wide range of variability in k600 at small spatial scales. Values of k600‐K ranged from 7.42 to 330 m/d (mean = 116 ± 95.1 m/d), whereas values of k600‐M ranged from 23.5 to 444 m/d (mean = 121 ± 127 m/d). Temporal variability in k600 was driven by increases in Stream discharge caused by rain events, whereas spatial variability was driven by channel morphology, including Stream width and slope. The two methods were in good agreement (less than 16% difference) at high and Medium Stream discharge (above 7.0 L/s). However, the two methods considerably differed from one another (up to 73% difference) at low Stream discharge (below 7.0 L/s, which represents 60% of the observations collected). Our study provides the first estimates of k600 values in a high‐elevation tropical catchment across steep environmental gradients and highlights the combined effects of hydrology and Stream morphology in co‐regulating gas transfer velocities in páramo Streams