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.

Ground-Coupled Heat and Moisture Transfer From Buildings: Part 2 — Application

2001 ◽  
Author(s):  
Michael P. Deru ◽  
Allan T. Kirkpatrick
Keyword(s):  
Heat Transfer ◽  
Moisture Transfer ◽  
Transfer Program ◽  
Soil Thermal Conductivity ◽  
Heat And Moisture Transfer ◽  
Conduction Model ◽  
Building Foundation ◽  
Dimensional Finite Element ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

Abstract In this paper the effects of moisture on the heat transfer from two basic types of building foundations, a slab-on-grade and a basement, are examined. A two-dimensional finite element heat and moisture transfer program is used to show the effects of precipitation, soil type, foundation insulation, water table depth, and freezing on the heat transfer from the building foundation. Comparisons are made with a simple heat conduction model to illustrate the dependency of the soil thermal conductivity on moisture content.

scholarly journals Ground-Coupled Heat and Moisture Transfer from Buildings Part 2–Application

2001 ◽  
Vol 124 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Michael P. Deru ◽  
Allan T. Kirkpatrick
Keyword(s):  
Heat Transfer ◽  
Moisture Transfer ◽  
Transfer Program ◽  
Soil Thermal Conductivity ◽  
Heat And Moisture Transfer ◽  
Conduction Model ◽  
Building Foundation ◽  
Dimensional Finite Element ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture

In this paper, the effects of moisture on the heat transfer from two basic types of building foundations, a slab-on-grade and a basement, are examined. A two-dimensional finite element heat and moisture transfer program is used to show the effects of precipitation, soil type, foundation insulation, water table depth, and freezing on the heat transfer from the building foundation. Comparisons are made with a simple heat conduction model to illustrate the dependency of the soil thermal conductivity on moisture content.

NUMERICAL SIMULATION FOR EFFECTS OF MICROCAPSULED PHASE CHANGE MATERIAL (MPCM) DISTRIBUTION ON HEAT AND MOISTURE TRANSFER IN POROUS TEXTILES

2009 ◽  
Vol 23 (03) ◽  
pp. 501-504 ◽  
Author(s):  
FENGZHI LI
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Materials ◽  
Moisture Transfer ◽  
Physical Parameters ◽  
Heat And Moisture Transfer ◽  
Numerical Predictions ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture ◽  
Transfer Properties

In recent years, the use of phase change materials (PCM) to improve heat and moisture transfer properties of clothing has gained considerable attention. The PCM distribution in the clothing impacts heat and moisture transfer properties of the clothing significantly. For describing the mechanisms of heat and moisture transfer in clothing with PCM and investigating the effect of the PCM distribution, a new dynamic model of coupled heat and moisture transfer in porous textiles with PCM was developed. The effect of water content on physical parameters of textiles and heat transfer with phase change in the PCM microcapsules were considered in the model. Meanwhile, the numerical predictions were compared with experimental data, and good agreement was observed between the two, indicating that the model was satisfactory. Also the effects of the PCM distribution on heat transfer in the textiles-PCM microcapsule composites were investigated by using the model.

scholarly journals Experimental and numerical studies of heat and moisture transfer in soils at various conditions

2021 ◽  
Author(s):  
Lam Dang
Keyword(s):  
Moisture Transfer ◽  
Soil Column ◽  
Heat And Moisture Transfer ◽  
Conduction Model ◽  
Transient Time ◽  
One Dimensional ◽  
Experimental Apparatus ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture ◽  
Temperature Responses

The main purpose of this study is to provide a better understanding of heat and moisture transfer in soils under high-temperature (> 40°C) conditions. Through a numerical analysis of the experimental apparatus using COMSOL, it was found that one-dimensional formulation based on the finite volume method was sufficient to numerically study the governing partial differential equations of coupled heat and moisture transfer in soils. An existing experimental apparatus and some of its experimental procedures were improved in order to obtain more accurate test results. Based on a conservative uncertainty analysis, the maximum overall uncertainties at 95% confidence level were 15.5% for thermal conductivity and 9.20% for soil volumetric heat capacity. The maximum overall uncertainty for moisture content was estimated to be 48.6% at saturation ratio (SR) of 0.25 and reduced to 29.9% at SR of 0.5. The heat and moisture transfer in the soil column based on the coupled governing equations were numerically simulated to compare with the experiments done on three soil types (fine soil BC1, medium soil NB2, and coarse soil QC2) with different saturation ratios (from 0.00 to 0.70) under different heating conditions (mostly from 42C and up). It was found that the simulations for coarser soils were less accurate to predict the moisture movements and temperature responses because the moisture could flow faster in coarser soils. The pure heat conduction model was also compared with the experiments and showed higher errors in the temperature responses (~2% minimum and ~5% maximum errors) than the equations of coupled heat and moisture transfer do Coarser soils, because of their higher sand contents, transferred more heat during transient time when the entire soil column was still quite wet, but less heat transferred during steady-state time when a part of the soil column became dry. In conclusion, the worst percentage differences between predicted and measured temperatures range from 0.89% to 3.52%, while the worst percentage differences between predicted and measured moisture contents range from 4.67% to 7.53%, using the one-dimensional formulations of the theoretical model of coupled heat and moisture transfer in soils

scholarly journals Experimental and numerical studies of heat and moisture transfer in soils at various conditions

2021 ◽  
Author(s):  
Lam Dang
Keyword(s):  
Moisture Transfer ◽  
Soil Column ◽  
Heat And Moisture Transfer ◽  
Conduction Model ◽  
Transient Time ◽  
One Dimensional ◽  
Experimental Apparatus ◽  
Coupled Heat And Moisture ◽  
Heat And Moisture ◽  
Temperature Responses

The main purpose of this study is to provide a better understanding of heat and moisture transfer in soils under high-temperature (> 40°C) conditions. Through a numerical analysis of the experimental apparatus using COMSOL, it was found that one-dimensional formulation based on the finite volume method was sufficient to numerically study the governing partial differential equations of coupled heat and moisture transfer in soils. An existing experimental apparatus and some of its experimental procedures were improved in order to obtain more accurate test results. Based on a conservative uncertainty analysis, the maximum overall uncertainties at 95% confidence level were 15.5% for thermal conductivity and 9.20% for soil volumetric heat capacity. The maximum overall uncertainty for moisture content was estimated to be 48.6% at saturation ratio (SR) of 0.25 and reduced to 29.9% at SR of 0.5. The heat and moisture transfer in the soil column based on the coupled governing equations were numerically simulated to compare with the experiments done on three soil types (fine soil BC1, medium soil NB2, and coarse soil QC2) with different saturation ratios (from 0.00 to 0.70) under different heating conditions (mostly from 42C and up). It was found that the simulations for coarser soils were less accurate to predict the moisture movements and temperature responses because the moisture could flow faster in coarser soils. The pure heat conduction model was also compared with the experiments and showed higher errors in the temperature responses (~2% minimum and ~5% maximum errors) than the equations of coupled heat and moisture transfer do Coarser soils, because of their higher sand contents, transferred more heat during transient time when the entire soil column was still quite wet, but less heat transferred during steady-state time when a part of the soil column became dry. In conclusion, the worst percentage differences between predicted and measured temperatures range from 0.89% to 3.52%, while the worst percentage differences between predicted and measured moisture contents range from 4.67% to 7.53%, using the one-dimensional formulations of the theoretical model of coupled heat and moisture transfer in soils

Analysis of Heat and Moisture Transfer Beneath Freezer Foundations-Part II

2004 ◽  
Vol 126 (2) ◽  
pp. 726-731 ◽  
Author(s):  
Moncef Krarti ◽  
Pirawas Chuangchid ◽  
Pyeongchan Ihm
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Numerical Solution ◽  
Moisture Transfer ◽  
Temperature Profiles ◽  
Two Dimensional ◽  
Soil Thermal Conductivity ◽  
Heat And Moisture Transfer ◽  
Conduction Model ◽  
Heat And Moisture

This paper discusses selected results from a numerical solution of two-dimensional heat and moisture transfer within frozen and unfrozen soils beneath freezer slab foundations. In particular, the numerical solution is used to determine soil temperature profiles as well as freezer foundation heat gains. Finally, an effective soil thermal conductivity is successfully utilized in a pure heat conduction model to predict ground-coupled heat gains for freezers.

scholarly journals The interaction of clothing ventilation with dry and evaporative heat transfer of jackets

2016 ◽  
Vol 28 (5) ◽  
pp. 570-581 ◽  
Author(s):  
Xiao-Qun Dai ◽  
George Havenith
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Moisture Transfer ◽  
Heat Diffusion ◽  
Vapor Permeability ◽  
Heat And Moisture Transfer ◽  
Content Type ◽  
Dry Heat ◽  
Evaporative Heat Transfer ◽  
Heat And Moisture

Purpose The purpose of this paper is to investigate the effect of air and vapor permeability of jacket materials on ventilation, heat and moisture transfer. Design/methodology/approach Clothing ventilation (V), thermal insulation (I) and vapor resistance (R e ) of three jackets made of different materials (normal textile, PVC and “breathable” membrane coated textile), worn on an articulated thermal manikin in a controlled climate chamber, were measured under various conditions, respectively. The various conditions of microenvironment ventilation were created by making the manikin stand and walk, combined with three wind speeds of <0.2, 0.4 and 2.0 m/s, respectively. Findings In the condition without any forced convection, the air permeability makes no big difference to dry and evaporative heat transfer among the jackets, while the vapor permeability plays a big role in the evaporative heat loss. In the condition with forced convection, the dry heat diffusion is strongly coupled to the evaporative heat transfer in air and vapor permeable textile material. Research limitations/implications The effects of ventilation on heat and moisture transfer varies because of different ways of ventilation arising: penetration through the fabric is proven to be the most effective way in vapor transfer although it does not seem as helpful for dry heat diffusion. Originality/value The achievements in this paper deepens the understanding of the process of the dry and evaporative heat transfer through clothing, provides clothing designer guidance to choose proper materials for a garment, especially work clothing.

MODELING AND VERIFICATION OF HEAT AND MOISTURE TRANSFER IN AN ENTHALPY EXCHANGER MADE OF PAPER MEMBRANE

2012 ◽  
Vol 20 (03) ◽  
pp. 1250015 ◽  
Author(s):  
EUL-JONG LEE ◽  
JUNG-PYO LEE ◽  
HYUN-MIN SIM ◽  
NAE-HYUN KIM
Keyword(s):  
Heat Transfer ◽  
Moisture Transfer ◽  
Membrane Resistance ◽  
Transfer Model ◽  
Heat And Moisture Transfer ◽  
Total Thermal Resistance ◽  
Transfer Resistance ◽  
Fin Efficiency ◽  
Heat And Moisture ◽  
And Diffusion

In this study, heat and moisture transfer model of an enthalpy exchanger is proposed. With separately measured sorption constant and diffusion coefficient, the model predicts the heat and moisture transfer effectiveness of an enthalpy exchanger. Two sample enthalpy exchangers were tested at a KS condition to verify the model. The model predicts the heat transfer effectiveness within 4%, and the moisture transfer effectiveness within 10%. Pressure drop is predicted within 6%. The spacer fin efficiency for heat transfer was 0.11 to 0.13. The fin efficiency for moisture transfer, however, was negligibly small. For heat transfer, the conduction resistance to total thermal resistance was less than 1%. For moisture transfer, however, membrane resistance was dominant to convective moisture transfer resistance.

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