Estimation of Sensible and Latent Heat Fluxes from Soil Surface Temperature Using a Linear Air-Land Heat Transfer Model

1994 ◽  
Vol 33 (4) ◽  
pp. 477-489 ◽  
Author(s):  
Fujio Kimura ◽  
Yugo Shimizu
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Latent Heat ◽  
Soil Surface ◽  
Heat Transfer Model ◽  
Heat Fluxes ◽  
Transfer Model ◽  
Soil Surface Temperature

Transient Three-Dimensional Heat Transfer Model of a Solar Thermochemical Reactor for H2O and CO2 Splitting via Nonstoichiometric Ceria Redox Cycling

2013 ◽  
Author(s):  
Justin Lapp ◽  
Wojciech Lipiński
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Fuel Efficiency ◽  
Three Dimensional ◽  
Reactor Design ◽  
Heat Transfer Model ◽  
Heat Fluxes ◽  
Transfer Model ◽  
Rotating Cylinders ◽  
Solar Receiver

A transient heat transfer model is developed for a solar reactor prototype for H2O and CO2 splitting via two-step non-stoichiometric ceria cycling. Counter-rotating cylinders of reactive and inert materials cycling between high and low temperature zones permit continuous operation and heat recovery. To guide the reactor design a transient three-dimensional heat transfer model is developed based on transient energy conservation, accounting for conduction, convection, radiation, and chemical reactions. The model domain includes the rotating cylinders, a solar receiver cavity, and insulated reactor body. Radiative heat transfer is analyzed using a combination of the Monte Carlo method, Rosseland diffusion approximation, and the net radiation method. Quasi-steady state distributions of temperatures, heat fluxes, and the non-stoichiometric coefficient are reported. Ceria cycles between temperatures of 1708 K and 1376 K. A heat recovery effectiveness of 28% and solar-to-fuel efficiency of 5.2% are predicted for an unoptimized reactor design.

Analysis and Modelling of Temperature at Lake’s Water – Atmosphere Interface

2021 ◽  
Author(s):  
Vassilis Z. Antonopoulos ◽  
Soultana K. Gianniou
Keyword(s):  
Heat Transfer ◽  
Energy Balance ◽  
Surface Temperature ◽  
Water Surface ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Net Radiation ◽  
Water Surface Temperature ◽  
Simulation Results ◽  
Input Variables

Abstract The knowledge of micrometeorological conditions on water surface of impoundments is crucial for the better modeling of the temperature and water quality parameters distribution in the water body and against the climatic changes. Water temperature distribution is an important factor that affects most physical, chemical and biological processes and reactions occurring in lakes. In this work, different processes of water surface temperature of lake’s estimation based on the energy balance method are considered. The daily meteorological data and the simulation results of energy balance components from an integrated heat transfer model for two complete years as well as the lake’s characteristics for Vegoritis lake in northern Greece were used is this analysis.The simulation results of energy balance components from a heat transfer model are considered as the reference and more accurate procedure to estimate water surface temperature. These results are used to compare the other processes. The examined processes include a) models of heat storage changes in relationship to net radiation (Qt(Rn) values, b) net radiation estimation with different approaches, as the process of Slob’s equation with adjusted coefficients to lake data, and c) ANNs models with different architecture and input variables. The results show that the model of heat balance describes the water surface temperature with high accuracy (r2=0.916, RMSE=2.422oC). The ANN(5,6,1) model in which Tsw(i-1) is incorporated in the input variables was considered the better of all other ANN structures (r2=0.995, RMSE=0.490oC). The use of different approaches for simulating net radiation (Rn) and Qt(Rn) in the equation of water surface temperature gives results with lower accuracy.

Optimal Design of Breakout Prediction System of Slab Continuous Casting

2012 ◽  
Vol 457-458 ◽  
pp. 138-141
Author(s):  
Yi Wang ◽  
Xin Jian Ma
Keyword(s):  
Heat Transfer ◽  
Optimal Design ◽  
Continuous Casting ◽  
Surface Temperature ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Prediction System ◽  
Slab Continuous Casting ◽  
New Development ◽  
Prediction Technique

This paper describes the new development of the breakout prediction technique based a heat transfer model. The model aims to minimize the variation in surface temperature. The breakout prediction system of slab continuous casting has been analyzed with consideration of the principles, model and thermocouples installation. The system has been designed and implemented in the steel plants.

Sensitivity of soil surface temperature in a force-restore equation to heat fluxes and deep soil temperature

1999 ◽  
Vol 19 (14) ◽  
pp. 1617-1632 ◽  
Author(s):  
Dragutin T. Mihailović ◽  
George Kallos ◽  
Ilija D. Arsenić ◽  
Branislava Lalić ◽  
Borivoj Rajković ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Soil Temperature ◽  
Soil Surface ◽  
Heat Fluxes ◽  
Deep Soil ◽  
Soil Surface Temperature

Transient Three-Dimensional Heat Transfer Model of a Solar Thermochemical Reactor for H2O and CO2 Splitting Via Nonstoichiometric Ceria Redox Cycling

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Justin Lapp ◽  
Wojciech Lipiński
Keyword(s):  
Heat Transfer ◽  
Heat Recovery ◽  
Fuel Efficiency ◽  
Radiation Heat Transfer ◽  
Three Dimensional ◽  
Heat Transfer Model ◽  
Heat Fluxes ◽  
Transfer Model ◽  
Solar Thermochemical ◽  
Solar Receiver

A transient three-dimensional heat transfer model is developed for a 3 kWth solar thermochemical reactor for H2O and CO2 splitting via two-step nonstoichiometric ceria cycling. The reactor consists of a windowed solar receiver cavity, counter-rotating reactive and inert cylinders, and insulated reactor walls. The counter-rotating cylinders allow for continuous fuel production and heat recovery. The model is developed to solve energy conservation equations accounting for conduction, convection, and radiation heat transfer modes, and chemical reactions. Radiative heat transfer is analyzed using a combination of the Monte Carlo ray-tracing method, the net radiation method, and the Rosseland diffusion approximation. Steady-state temperatures, heat fluxes, and nonstoichiometry are reported. A temperature swing of up to 401 K, heat recovery effectiveness of up to 95%, and solar-to-fuel efficiency of up to 5% are predicted in parametric studies.

Methodology to Characterize Heat Transfer Phenomena in Small Automotive Turbochargers: Experiments and Modelling Based Analysis

2014 ◽  
Author(s):  
J. R. Serrano ◽  
P. Olmeda ◽  
F. J. Arnau ◽  
A. Dombrovsky ◽  
L. Smith
Keyword(s):  
Heat Transfer ◽  
Standard Technique ◽  
Heat Transfer Model ◽  
Heat Fluxes ◽  
Experimental Methodology ◽  
Pollutant Emissions ◽  
Transfer Model ◽  
Great Effort ◽  
Heat Transfer Phenomenon ◽  
Comprehensive Study

These days great effort is devoted to the study of turbocharging in order to minimize fuel consumption and pollutant emissions of turbocharged reciprocating engines. Among all the processes taking place in small automotive turbochargers, the heat transfer phenomenon is one of the least analysed in a systematic way. However turbocharger heat transfer phenomena are very important at low engine loads. An accurate prediction of gas temperatures at turbine and compressor outlet and fluid temperatures at the water and oil outlet ports is not possible without considering heat transfer phenomena in the turbocharger. In the present work a comprehensive study of these phenomena is presented, showing their relevance compared to gas enthalpy variations through the turbomachinery. The study provides an experimental methodology to consider the different heat fluxes in the turbocharger and modelling them by means of a lumped capacitance heat transfer model. The input data required for the model is obtained experimentally by a proper combination of both steady and transient tests. These tests are performed in different test benches, in which compressible fluids (gas) and incompressible fluids (oil) are used in a given sequence. The experimental data allows developing heat transfer correlations for the different turbocharger elements. These correlations take into account all the possible heat fluxes, discriminating between internal and external heat transfer. In order to analyse the relative importance of heat transfer phenomena in the predictability of the turbocharger performance and the different related variables; model results, in hot and cold conditions, have been compared with those provided by the standard technique, consisting on using look up maps of the turbocharger. The analysis of these results evidences the highly diabatic operative areas of the turbocharger and it provides clearly ground rules for using hot or cold maps. In addition, paper conclusions advise about using or not a heat transfer model, depending on the turbocharger variables and the operative conditions that one desires to predict.

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