Impact of Layered Soil on Foundation Heat Transfer for Slab-On Grade Floors

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Nizar Khaled ◽  
Khaled Rouissi ◽  
Moncef Krarti
Keyword(s):  
Heat Transfer ◽  
Analytical Solution ◽  
Soil Temperature ◽  
Soil Properties ◽  
Heat Loss ◽  
Layered Soil ◽  
Soil Medium ◽  
Coupled Heat Transfer ◽  
Building Foundation ◽  
The Impact

This paper presents an analytical solution associated with the steady-periodic heat transfer for a typical slab-on-grade floor building foundation in contact with a nonhomogeneous soil medium. In particular, the solution accounts for the impact of the above-grade wall thickness on the ground-coupled heat transfer. The interzone temperature estimation profile (ITPE) technique is utilized to obtain the analytical solution to determine soil temperature distributions and to estimate foundation heat loss/gain from slab-on-grade floors. In this paper, the impact of the nonhomogeneous soil properties on the transient foundation heat transfer is investigated for various slab configurations and soil thermal properties. The presented solution presents the first ITPE analytical solution for building foundation coupled with layered soil medium. The results indicate that nonhomogeneous soil properties have a significant effect on soil temperature distribution and on total slab heat loss. In particular, it is found that an error of up to 20% in estimating total slab heat transfer can be incurred if homogeneous soil medium is considered instead of a two-layered ground.

Impact of Layered Soil on Foundation Heat Transfer for Slab-On Grade Floors

2009 ◽  
Author(s):  
Nizar Khaled ◽  
Moncef Krarti
Keyword(s):  
Heat Transfer ◽  
Temperature Estimation ◽  
Soil Medium ◽  
Coupled Heat Transfer ◽  
Building Foundation ◽  
Soil Thermal Properties ◽  
Homogeneous Soil ◽  
Periodic Heat ◽  
The Impact ◽  
Zone Temperature

This paper presents an analytical solution for the steady-periodic heat transfer for a typical slab-on-grade floor building foundation beneath non-homogeneous soil medium. The impact of the above-grade walls on ground-coupled heat transfer is accounted for in the presented solution. The Inter-zone Temperature Estimation Profile (ITPE) technique is utilized to obtain the 3-D solutions to determine soil temperature distributions and to estimate foundation heat loss/gain from slab-on-grade floors. The impact of the non-homogeneous soil properties on the transient foundation heat transfer is investigated for various slab configurations and soil thermal properties.

scholarly journals Prediction of the impact of climate change on the thermal performance of walls and roof in Morocco

2021 ◽  
Author(s):  
Yassine Kharbouch ◽  
Mohamed Ameur
Keyword(s):  
Climate Change ◽  
Heat Transfer ◽  
Heat Loss ◽  
Thermal Performance ◽  
Building Energy ◽  
Building Envelope ◽  
Heat Gain ◽  
Impact Of Climate Change ◽  
Summer Heat ◽  
The Impact

Abstract Climate change has become a real challenge in different fields, including the building sector. Understanding and assessing the impact of climate change on building energy performance is still necessary to elaborate new climate-adaptive design measures for future buildings. The building energy consumption for heating and cooling is mainly related to the building envelope thermal performance. In this study, the winter heat loss and summer heat gain indicators are proposed to assess and analyse the potential impact of climate change on opaque building envelope elements for different climate zones in Morocco over the next 40 years. For that purpose, a one-dimensional heat transfer model is used to simulate the heat transfer through the multi-layer structure of the wall/roof. A medium climate change scenario is considered in this study. The results showed that the current average walls and roof summer heat gain is expected to increase of about 19.2–54.3% by the 2060s depending on the climate zone, versus a less important decrease in winter heat loss varies between –10.6 and –20.6%. This paper provides a reliable evaluation of the climate change impact on building envelope thermal performance, which leads to better adjustments in future building envelope designs.

Estimation of building heat transfer coefficients from in-use data

2019 ◽  
Vol 38 (1) ◽  
pp. 38-50 ◽  
Author(s):  
Matthew Li ◽  
David Allinson ◽  
Kevin Lomas
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Heat Balance ◽  
High Heat ◽  
Quasi Steady State ◽  
Content Type ◽  
Sources And Sinks ◽  
Energy Flows ◽  
Steady State Heat ◽  
The Impact

Purpose The purpose of this paper is to identify the impact of traditionally unmonitored energy sources and sinks on assessment of the as-built thermal performance of occupied homes. The analysis aims to demonstrate the potential scale of uncertainties introduced in a heat balance estimation of the heat transfer coefficient (HTC) when using in-use monitored data. Design/methodology/approach Energy flows for two UK homes – one a 1930s dwelling with high heat loss, the second a higher-performing 2014-built home – are predicted using the UK Government’s standard assessment procedure (SAP) and visualised using Sankey diagrams. Selected modelled energy flows are used as inputs in a quasi-steady state heat balance to calculate in-use HTCs as if from measured data sets gathered in occupied homes. The estimated in-use HTCs are compared against SAP-calculated values to illustrate the impact of including or omitting various heat sources and sinks. Findings The results demonstrate that for dwellings with low heat loss, the increased proportion of heating demand met by unmetered internal and solar gains informs a greater sensitivity of a heat balance estimation of the HTC to their omission. While simple quasi-steady state heat balance methods may be appropriate for dwellings with very high heat loss, alternative approaches are likely to be required for those with lower heat loss. Originality/value A need to understand the impacts of unmetered heat flows on the accuracy with which a building’s thermal performance may be inferred from in-use monitored data is identified: this paper illustrates the scale of these impacts for two homes at opposite ends of the energy performance scale.

scholarly journals Convective Heat Transfer of Spring Meltwater Accelerates Active Layer Phase Change in Tibetan Permafrost Areas

2021 ◽  
Author(s):  
Yi Zhao ◽  
Zhuotong Nan ◽  
Hailong Ji ◽  
Lin Zhao
Keyword(s):  
Heat Transfer ◽  
Soil Temperature ◽  
Convective Heat Transfer ◽  
Active Layer ◽  
Convective Heat ◽  
Thermal Regime ◽  
Transport Processes ◽  
Model Parameters ◽  
Soil Layers ◽  
The Impact

Abstract. Convective heat transfer (CHT) is one of the important processes that controls the near ground surface heat transfer in permafrost areas. However, this process has often not been considered in most permafrost simulation studies and its influence on the freeze-thaw processes of the active layer lacks quantitative investigation. The Simultaneous Heat and Water (SHAW) model is one of the few land surface models in which the CHT process is well incorporated in the soil heat-mass transport processes. We applied the SHAW model to investigate the impacts of CHT on active layer thermal dynamics on the Tanggula station, a typical permafrost site located at the eastern Qinghai-Tibetan Plateau with abundant meteorological and soil temperature/moisture observation data. The 2008–2009 observed hourly data were used to calibrate the model parameters and those of 2010 for validation. A control experiment was carried out to quantify the changes in active layer thermal regime affected by vertical advection of liquid water, consisting of three setups: using (1) the original SHAW model with full consideration of CHT; (2) a modified SHAW model ignoring the CHT due to infiltration from the surface, and (3) a modified SHAW model ignoring complete CHT processes in the system. The impacts of vapor convection are not considered in this experiment. The results show that the CHT events mainly happened during thawing periods when the active layer melted at shallow (0–0.2 m) and middle (0.4–1.3 m) soil depths, and its impact on soil thermal regime at shallow depths was significantly greater in spring melting periods than in summer. The impact was minimal in freezing periods and in deep soil layers. During melting periods, temperatures in the shallow and middle soil depths simulated under the scenario considering CHT were higher by up to 10.0 and 1.5 °C, respectively, than those under the scenarios ignoring CHT. The ending dates of zero-curtain effect were considerably advanced with CHT considered, due to the warming effect of CHT associated with infiltration. However, the opposite cooling effect also existed due to presence of upward liquid fluxes and thermal differences between the soil layers. In some certain period, the advection flow including partial return flow reduced the temperatures in the shallow and middle depths by as much as −5.0 and −1.0 °C, respectively. The overall annual effect of CHT by liquid flux is to increase soil temperature in the active layer and favors thawing of frozen ground at the study site.

Impact of Above-Grade Walls on Three-Dimensional Building Foundation Heat Transfer From Slab-On Grade Floors

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Moncef Krarti
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Closed Form Solution ◽  
Form Solution ◽  
Heat Losses ◽  
Dimensional Solution ◽  
Simplified Approach ◽  
Coupled Heat Transfer ◽  
Profile Estimation ◽  
The Impact

This paper presents a new three-dimensional analytical solution for transient ground-coupled heat transfer associated with slab-on-grade floor building foundations. The impact of above-grade walls on ground-coupled heat transfer is accounted for in the presented solution. The interzone temperature profile estimation (ITPE) technique is utilized to obtain the 3D solution suitable to determine soil temperature distributions and to estimate foundation heat loss/gain from slab-on-grade floors. The ITPE results are validated against results obtained from a closed-form solution in the case of steady-state conditions. It is found that that the above-grade walls can significantly affect the foundation heat losses especially for uninsulated slabs. Moreover, a simplified approach is proposed to obtain three-dimensional foundation heat losses from a two-dimensional solution.

Analysis of Heat and Moisture Transfer Beneath Freezer Foundations—Part I

2004 ◽  
Vol 126 (2) ◽  
pp. 716-725 ◽  
Author(s):  
Pirawas Chuangchid ◽  
Pyeonchan Ihm ◽  
Moncef Krarti
Keyword(s):  
Heat Transfer ◽  
Moisture Transfer ◽  
Experimental Tests ◽  
Frozen Soil ◽  
Heat And Moisture Transfer ◽  
Conduction Model ◽  
Coupled Heat Transfer ◽  
Time Required ◽  
Heat And Moisture ◽  
The Impact

This paper provides a numerical solution for simultaneous heat and moisture transfer within frozen soil beneath slab foundations of refrigerated warehouses. The developed solution is validated using data from experimental tests. A parametric analysis is then performed to determine the impact of slab insulation levels and to estimate the time required to reach steady-state ground-coupled heat transfer conditions. Finally, the solution is utilized to determine an effective soil thermal conductivity that could be used in a purely heat conduction model for ground-coupled heat transfer beneath freezers.

scholarly journals Heat transfer analysis in stretching/shrinking rectangular fin with convection and radiation

2021 ◽  
Author(s):  
Sharif Ullah ◽  
Amir Ali ◽  
Zia Din
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Analytical Solution ◽  
Heat Transfer Analysis ◽  
Combined Effects ◽  
Transform Method ◽  
Differential Transform ◽  
Effects Of Radiation ◽  
The Impact ◽  
Good Agreement

The aim of this work is to enhance the heat transfer and study the efficiency of stretching/shrinking, radiating and rectangular fins. The effect of the dimensionless parameters, that is, radiation-conduction, convection-conduction stretching, thermo-geometric parameters as well as the Peclet number, and surface temperature are investigated on the efficiency of stretching/shrinking and rectangular fins. The considered model is studied analytically using Differential Transform Method (DTM). The result is analyzed with the numerical solution for the accuracy of the semi-analytical solution, where good agreement is obtained. The impact of the considered parameters is studied numerically on the temperature distribution, fin’s tip temperature, and the efficiency of the fin, where the combined effects of radiation and stretching/ shrinking enhance the system in the heat transfer with better efficiency. The shrinking of the fin with radiation increases the efficiency as compared to stretching with radiation is observed, which plays a significant role in mechanical engineering.

scholarly journals Analytical study of joint heat transfer between a gasdynamic boundary layer and an anisotropic strip

2020 ◽  
Vol 12 (S) ◽  
pp. 233-243
Author(s):  
Thant ZIN HEIN ◽  
Boris A. GARIBYAN ◽  
Sergey N. VAKHNEEV ◽  
Olga V. TUSHAVINA ◽  
Vladimir F. FORMALEV
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Analytical Solution ◽  
Boundary Conditions ◽  
Closed Form Solution ◽  
Form Solution ◽  
Heat Fluxes ◽  
Aerodynamic Heating ◽  
Arbitrary Boundary ◽  
Coupled Heat Transfer

When solving the problems of coupled heat transfer between viscous flows and streamlined bodies under the conditions of aerodynamic heating of aircraft, it is necessary to overcome significant difficulties. They associated primarily with determining the boundary conditions. The paper investigates the joint (coupled) heat transfer between a heat and gas dynamic boundary layer and an anisotropic strip under conditions of aerodynamic heating based on the obtained analytical solution of the second initial boundary value problem of thermal conductivity in an anisotropic strip with arbitrary boundary conditions. Since the system of equations of the gasdynamic boundary layer is essentially nonlinear, mainly numerical methods are used to solve it. For an incompressible boundary layer near the critical point of a blunt wedge, an analytical solution is obtained to determine the components of the velocity vector, density, temperature, and heat fluxes. The closed-form solution to the conjugate problem was received in the form of a Fredholm integral equation of second kind. The results of numerical experiments are obtained and analyzed.

scholarly journals Coupled heat transfer between a viscous shock gasdynamic layer and a transversely streamlined anisotropic half-space

2020 ◽  
Vol 12 (S) ◽  
pp. 211-220
Author(s):  
Olga V. TUSHAVINA
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Boundary Condition ◽  
Analytical Solution ◽  
Half Space ◽  
Stokes Equations ◽  
Conjugate Problem ◽  
Viscous Shock Layer ◽  
Boundary Layer Equations ◽  
Coupled Heat Transfer

The purpose of the article is to analytically solve the conjugate problem of heat transfer in a viscous shock layer on a blunt object and thermal conductivity in an anisotropic half-space. A feature of the flow around such bodies near the critical point is that in this case, the boundary layer equations are not satisfied and it is necessary to solve the Navier-Stokes equations together with the equations of continuity, state, and energy, however, in a stationary formulation of an incompressible flow. The problem of coupled heat transfer between a viscous shock gasdynamic layer and anisotropic half-space with the assumption of incompressibility of the gasdynamic flow behind the normal part of the shock wave is posed. An analytical solution to this problem is obtained with a boundary condition at the gas-solid object interface in the form of a parameter – temperature, as well as an analytical solution to the thermal conductivity problem in an anisotropic half-space with the same boundary condition.

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