scholarly journals Thermal behavior of light earth used for building insulation: Insight on PCM introduction impact

2021 ◽  
Vol 2069 (1) ◽  
pp. 012120
Author(s):  
Farjallah Alassaad ◽  
Karim Touati ◽  
Daniel Levacher ◽  
Nassim Sebaibi
Keyword(s):  
Thermal Properties ◽  
Building Materials ◽  
Phase Change Materials ◽  
Natural Fiber ◽  
Research Work ◽  
Thermal Inertia ◽  
Thermal Response ◽  
Thermal Insulating ◽  
High Thermal Inertia ◽  
The Impact

Abstract To reduce building significant contribution to greenhouse gas emissions, architects and engineers are seeking eco-friendly construction solutions. Among investigated options, building’s thermal insulation and heat storage can be cited. In this regard, earth-based materials are attracting particular interest. These last years, there is a renewed interest in these eco-friendly building materials and techniques. This is due to many advantages that they present: excellent humidity regulation ability and high thermal inertia. Present study aims to improve light earth thermal properties. Specifically, this research work focuses on the development of an insulating and heat storing material. To achieve this, phase change materials (PCM) are incorporated in soil-natural fiber mixtures. In fact, different light earth samples are first prepared. Then, thermally characterized to highlight the impact of PCM on the light earth thermal insulating, heat storing properties and thermal response to changing boundary conditions. The incorporation of PCM showed an interesting improvement of the light earth thermal properties namely on thermal conductivity, specific heat capacity, and thermal comfort time.

scholarly journals Novel active method for the estimation of a building wall thermal resistance

2020 ◽  
Vol 172 ◽  
pp. 14008
Author(s):  
Adrien François ◽  
Laurent Ibos ◽  
Vincent Feuillet ◽  
Johann Meulemans
Keyword(s):  
Steady State ◽  
Thermal Resistance ◽  
Building Materials ◽  
Thermal Inertia ◽  
Thermal Response ◽  
Heat Fluxes ◽  
External Temperature ◽  
Building Wall ◽  
High Thermal Inertia

The thermal resistance of a wall can be readily measured in steady-state. However, such a state is seldomly achieved in a building because of the variation of outdoor conditions as well as the high thermal inertia of building materials. This paper introduces a novel active (dynamic) method to measure the thermal resistance of a building wall. Not only are active approaches less sensitive to external temperature variations, they also enable to perform measurements within only a few hours. In the proposed methodology, an artificial thermal load is applied to a wall (heating of the indoor air) and its thermal response is monitored. Inverse techniques are used with a reduced model to estimate the value of the thermal resistance of a wall from the measured temperatures and heat fluxes. The methodology was validated on a known load-bearing wall built inside a climate chamber. The results were in good agreement with reference values derived from a steady-state characterization of the wall. The method also demonstrated a good reproducibility.

scholarly journals A two-layer canopy model with thermal inertia for an improved snowpack energy balance below needleleaf forest (model SNOWPACK, version 3.2.1, revision 741)

2015 ◽  
Vol 8 (8) ◽  
pp. 2379-2398 ◽  
Author(s):  
I. Gouttevin ◽  
M. Lehning ◽  
T. Jonas ◽  
D. Gustafsson ◽  
M. Mölder
Keyword(s):  
Energy Balance ◽  
Temperature Drop ◽  
Model Performance ◽  
Ground Surface ◽  
Thermal Inertia ◽  
Thermal Response ◽  
Canopy Temperature ◽  
Current Form ◽  
The Impact ◽  
Canopy Model

Abstract. A new, two-layer canopy module with thermal inertia as part of the detailed snow model SNOWPACK (version 3.2.1) is presented and evaluated. As a by-product of these new developments, an exhaustive description of the canopy module of the SNOWPACK model is provided, thereby filling a gap in the existing literature. In its current form, the two-layer canopy module is suited for evergreen needleleaf forest, with or without snow cover. It is designed to reproduce the difference in thermal response between leafy and woody canopy elements, and their impact on the underlying snowpack or ground surface energy balance. Given the number of processes resolved, the SNOWPACK model with its enhanced canopy module constitutes a sophisticated physics-based modeling chain of the continuum going from atmosphere to soil through the canopy and snow. Comparisons of modeled sub-canopy thermal radiation to stand-scale observations at an Alpine site (Alptal, Switzerland) demonstrate improvements induced by the new canopy module. Both thermal heat mass and the two-layer canopy formulation contribute to reduce the daily amplitude of the modeled canopy temperature signal, in agreement with observations. Particularly striking is the attenuation of the nighttime drop in canopy temperature, which was a key model bias. We specifically show that a single-layered canopy model is unable to produce this limited temperature drop correctly. The impact of the new parameterizations on the modeled dynamics of the sub-canopy snowpack is analyzed. The new canopy module yields consistent results but the frequent occurrence of mixed-precipitation events at Alptal prevents a conclusive assessment of model performance against snow data. The new model is also successfully tested without specific tuning against measured tree temperature and biomass heat-storage fluxes at the boreal site of Norunda (Sweden). This provides an independent assessment of its physical consistency and stresses the robustness and transferability of the chosen parameterizations. The SNOWPACK code including the new canopy module, is available under Gnu General Public License (GPL) license and upon creation of an account at https://models.slf.ch/.

scholarly journals A two-layer canopy with thermal inertia for an improved modelling of the sub-canopy snowpack energy-balance

2015 ◽  
Vol 8 (1) ◽  
pp. 209-262 ◽  
Author(s):  
I. Gouttevin ◽  
M. Lehning ◽  
T. Jonas ◽  
D. Gustafsson ◽  
M. Mölder
Keyword(s):  
Energy Balance ◽  
Temperature Drop ◽  
Model Performance ◽  
Thermal Inertia ◽  
Thermal Response ◽  
Canopy Temperature ◽  
Night Time ◽  
The Difference ◽  
Snow Model ◽  
The Impact

Abstract. A new, two-layer canopy module with thermal inertia as part of the detailed snow model SNOWPACK (version 3.2.1) is presented and evaluated. This module is designed to reproduce the difference in thermal response between leafy and woody canopy elements, and their impact on the underlying snowpack energy balance. Given the number of processes resolved, the SNOWPACK model with its enhanced canopy module constitutes a very advanced, physics-based atmosphere-to-soil-through-canopy-and-snow modelling chain. Comparisons of modelled sub-canopy thermal radiation to stand-scale observations at an Alpine site (Alptal, Switzerland) demonstrate the improvements of the new canopy module. Both thermal heat mass and the two-layer canopy formulation contribute to reduce the daily amplitude of the modelled canopy temperature signal, in agreement with observations. Particularly striking is the attenuation of the night-time drop in canopy temperature, which was a key model bias. We specifically show that a single-layered canopy model is unable to produce this limited temperature drop correctly. The impact of the new parameterizations on the modelled dynamics of the sub-canopy snowpack is analysed and yields consistent results but the frequent occurrence of mixed-precipitation events at Alptal prevents a conclusive assessment of model performance against snow data. The new model is also successfully tested without specific tuning against measured tree temperatures and biomass heat storage fluxes at the boreal site of Norunda (Sweden). This provides an independent assessment of its physical consistency and stresses the robustness and transferability of the parameterizations used.

scholarly journals Thermal Properties of Foamed Concrete with Addition of Empty Fruit Bunch (EFB) Fiber

2019 ◽  
Vol 8 (10) ◽  
pp. 4662-4670 ◽  
Keyword(s):  
Thermal Properties ◽  
Construction Industry ◽  
Building Materials ◽  
Natural Fiber ◽  
Construction Materials ◽  
Cost Effective ◽  
Fiber Reinforced Concrete ◽  
Empty Fruit Bunch ◽  
Construction Sector ◽  
Foamed Concrete

The key players in the construction industry around the globe are very enthusiastic in producing better construction materials that are cost-effective, durable, excellent thermal insulation, lightweight and long lasting without jeopardizing the environment. One of the best ways in producing such building materials are by incorporating industrial waste materials such as Empty Fruit Bunch (EFB) fiber in foamed concrete (FC). In recent years, the spotlight has been given towards the use of natural fiber reinforced concrete-based materials especially in Malaysia in a quest of economic and environmental upkeep particularly in the construction sector itself. Hence, this study intended to recognize the influence of Empty Fruit Bunch (EFB) fiber of four different contents (0.15%, 0.30%, 0.45% and 0.60 %) by mix volume on thermal properties of FC. There were three densities of 800kg/m3 , 1100kg/m3 and 1400kg/m3 we cast and tested. The mix design of FC (sand: cement: water) is fixed at the ratio of 1:1.5:0.45. The investigation focuses on three parameters which were thermal conductivity, thermal diffusivity and specific heat capacity. Results showed that the addition of EFB in FC plays an important role to improve the thermal performance holistically. The results demonstrated a great potential possesses by the EFB fiber to be utilized in cement-based materials such as the FC mix which is beneficial in reducing the thermal property or the transfer of heat in a produced concrete.

scholarly journals Transient Cooling Of A Cylinder In Cross Flow Bounded By An Adiabatic Wall

2018 ◽  
Vol 17 (2) ◽  
pp. 17
Author(s):  
Nawaf H Saeid ◽  
Bashir S. Abusahmin
Keyword(s):  
Thermal Properties ◽  
Cross Flow ◽  
Thermal Inertia ◽  
Cooling Process ◽  
Adiabatic Wall ◽  
Cold Air ◽  
Cooling Period ◽  
Air Stream ◽  
Storage Area ◽  
High Thermal Inertia

The present study investigates the parameters controlling the cooling process of acylindrical food in the storage area for a period of time. Transient analysis of theconduction and convection (conjugate) heat transfer from a cylindrical food, or acylindrical can filled with food is selected for numerical simulations. The cylinder isbounded by an adiabatic wall and the cold air is flowing normal to the cylinder axis (crossflow). The parameters investigated are: Reynolds number, food thermal properties(density, specific heat and thermal conductivity) and the cooling period. The range of theReynolds number is selected from 50 to 500 to be in laminar flow conditions. Threedifferent materials were selected according their thermal properties. The results arepresented to show the cooling process starting from blowing cold air stream on thecylinder for a period of 4 hours. The results show that the food with low thermal inertia iscooled faster than that of high thermal inertia. The present results show also that thecooling process can be shortened by increasing the air velocity and lower its temperature.

Potential of Cork Cement Composite as a Thermal Insulation Material

2015 ◽  
Vol 666 ◽  
pp. 17-29 ◽  
Author(s):  
Sukhdeo R. Karade
Keyword(s):  
Thermal Insulation ◽  
Building Materials ◽  
Environmental Concern ◽  
Cement Composite ◽  
Mineral Wool ◽  
Comfort Level ◽  
Environmental Benefits ◽  
Insulation Material ◽  
Thermal Insulating ◽  
The Impact

The growing environmental concern throughout the globe has led architects & engineers to design energy efficient buildings. Consequently, they are looking for building materials that can reduce the energy consumption in buildings to maintain the comfort level. Use of proper thermal insulating materials can reduce the energy required for heating or cooling of the buildings. Presently mineral wool and various foams are used for this purpose. Efforts are being made to use wastes in making thermal insulation materials so that the impact on environment can be further reduced. Cork granules are obtained as waste from the cork processing industries that make ‘bottle stoppers’ as a main product. These granules have a low density and could be used as lightweight aggregates for making concrete with low thermal conductivity. This article describes the physico-mechanical properties of lightweight cementitious composites made using cork granules. Further, environmental benefits of their application in thermal insulation of buildings has been discussed.

scholarly journals A brief review on mechanical and thermal properties of banana fiber based hybrid composites

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
P. Sivaranjana ◽  
V. Arumugaprabu
Keyword(s):  
Thermal Properties ◽  
Natural Fiber ◽  
Hybrid Composites ◽  
Fiber Reinforcement ◽  
Mechanical And Thermal Properties ◽  
Banana Fruit ◽  
Banana Plant ◽  
Banana Fiber ◽  
Banana Fibers ◽  
The Impact

AbstractThe usage of banana natural fibers along with polymer matrix composites had created much interest among the researchers due to their low cost, easy availability, strength and enhancement in properties such as mechanical, wear, electrical and thermal. Banana plant is cultivated all over the world which is familiarly used as food products especially banana fruit as well as many household items made from banana fibers. The natural fiber extracted from the banana stem proves to be a potential reinforcement in the composite manufacturing. This review is very much needed because of the enormous research reported on the banana fiber reinforced polymer composites, with such an excellent property offered by this banana fiber reinforcement the impact of hybridization and its need also to be addressed. This brief review article gives a detail information about the combinations of various hybrid composites produced using the banana fiber along with various other natural/synthetic fibers in the polymer matrixes and its performance improvement especially in the mechanical and thermal properties. From the review it was inferred that 30–50% increase in all the mechanical properties such as Tensile, Flexural and Impact strength. Also in addition an enhancement in thermal and moisture resistance also noted. In addition during this review the research gap observed is that the development of bio composites based on banana fiber is very limited and also the influence of banana fiber along with bio resin needs to be studied. The properties such as fatigue, fire resistance also to be analyzed using the banana fiber reinforcement.

scholarly journals Modeling the Evolution of Construction Solutions in Residential Buildings’ Thermal Comfort

2021 ◽  
Vol 11 (5) ◽  
pp. 2427
Author(s):  
Inês F. G. Reis ◽  
António Figueiredo ◽  
António Samagaio
Keyword(s):  
Thermal Comfort ◽  
Phase Change Materials ◽  
Residential Buildings ◽  
Thermal Inertia ◽  
Thermal Fluctuations ◽  
Energy Performance ◽  
Regulatory Requirements ◽  
Thermal Discomfort ◽  
High Thermal Inertia ◽  
Global Energy Consumption

The evolution of the construction sector over the years has been marked by the replacement of high thermal inertia mass constructions by increasingly lighter solutions that are subject to greater thermal fluctuations and, consequently, thermal discomfort. To minimize these effects, energy demanding space conditioning technologies are implemented, contributing significantly to the sector’s share of global energy consumption. Enhanced constructive solutions involving phase-change materials have been developed to respond to the constructive thermal inertia loss, influencing buildings’ thermal and energy performance. This work aims to model the evolution of the construction over the last decades to understand to what extent constructive characteristics influence the occupants’ thermal comfort. For this purpose, typical and enhanced solutions representing distinct constructive periods were simulated using the EnergyPlus® software through its graphical interface DesignBuilder® and the thermal comfort of the different solutions was evaluated using the adaptive model for thermal comfort EN16798-1. The main results reveal that more restraining regulatory requirements are indeed mitigating thermal discomfort situations. However, overheating phenomena can rise, creating worrying consequences in the short-medium term. Thus, countries with mild climates such as Portugal, must pay special attention to these effects, which may be aggravated by climate change.

scholarly journals On the Energy Performance of an Innovative Green Roof in the Mediterranean Climate

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5163
Author(s):  
Luca Evangelisti ◽  
Claudia Guattari ◽  
Gianluca Grazieschi ◽  
Marta Roncone ◽  
Francesco Asdrubali
Keyword(s):  
Urban Areas ◽  
Energy Savings ◽  
Thermal Inertia ◽  
Thermal Conditions ◽  
Noise Pollution ◽  
Green Roofs ◽  
Energy Performance ◽  
Thermal Insulating ◽  
Heating And Cooling ◽  
High Thermal Inertia

Green roofs have a thermal insulating effect known since ancient times. In the building sector, green roofs represent a sustainable passive solution to obtain energy savings, both during winter and summer. Moreover, they are a natural barrier against noise pollution, reducing sound reflections, and they contribute to clean air and biodiversity in urban areas. In this research, a roof-lawn system was studied through a long experimental campaign. Heat-flow meters, air and surface temperature sensors were used in two buildings characterized by different surrounding conditions, geometries and orientations. In both case studies, the thermal behaviors of the roof-lawn system were compared with the conventional roofs. In addition, a dynamic simulation model was created in order to quantify the effect of this green system on the heating and cooling energy demands. The roof-lawn showed a high thermal inertia, with no overheating during summer, and a high insulating capacity, involving energy savings during winter, and consequently better indoor thermal conditions.

scholarly journals Asteroid (101955) Bennu’s weak boulders and thermally anomalous equator

2020 ◽  
Vol 6 (41) ◽  
pp. eabc3699 ◽  
Author(s):  
B. Rozitis ◽  
A. J. Ryan ◽  
J. P. Emery ◽  
P. R. Christensen ◽  
V. E. Hamilton ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Thermal Properties ◽  
Mass Movement ◽  
Thermal Inertia ◽  
Temperature Dependent ◽  
Atmospheric Entry ◽  
Earth Asteroid ◽  
C Complex ◽  
High Thermal Inertia ◽  
Tentative Correlation

Thermal inertia and surface roughness are proxies for the physical characteristics of planetary surfaces. Global maps of these two properties distinguish the boulder population on near-Earth asteroid (NEA) (101955) Bennu into two types that differ in strength, and both have lower thermal inertia than expected for boulders and meteorites. Neither has strongly temperature-dependent thermal properties. The weaker boulder type probably would not survive atmospheric entry and thus may not be represented in the meteorite collection. The maps also show a high–thermal inertia band at Bennu’s equator, which might be explained by processes such as compaction or strength sorting during mass movement, but these explanations are not wholly consistent with other data. Our findings imply that other C-complex NEAs likely have boulders similar to those on Bennu rather than finer-particulate regoliths. A tentative correlation between albedo and thermal inertia of C-complex NEAs may be due to relative abundances of boulder types.

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