Experimental Investigation on Lightweight and Lime Stabilized Earth Composites

2015 ◽  
Vol 666 ◽  
pp. 31-45 ◽  
Author(s):  
Stefania Liuzzi ◽  
Pietro Stefanizzi
Keyword(s):  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Heat Capacity ◽  
Sorption Capacity ◽  
Bending Strength ◽  
The Other ◽  
Vapour Permeability ◽  
Final Performance ◽  
Mechanical Strengths ◽  
Measured Thermal Conductivity

An experimental investigation on different clay-based plasters with straw (lightweight plaster) and lime (stabilized plaster) was carried out. The aim of the study was to increase the knowledge on earthen materials in terms of final performance in building applications. In the first part of the study different thermal and hygric parameters were measured: thermal conductivity, specific heat capacity, sorption capacity, water vapour permeability. Furthermore, in order to test the suitability of the unfired clay as mortar, an analysis on the mechanical strengths was carried out, measuring the compressive and the bending strength. The results show, on one hand, that when straw is added to the basic mixture a significant improvement of the sorption capacity occurs, while, the addition of lime enhances the thermal properties. On the other hand, no significant improvement of mechanical strengths can be appreciated when using these additives. Nomenclature

scholarly journals Thermal Performance of Hybrid-Inspired Coolant for Radiator Application

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1100
Author(s):  
F. Benedict ◽  
Amit Kumar ◽  
K. Kadirgama ◽  
Hussein A. Mohammed ◽  
D. Ramasamy ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Volume Concentration ◽  
The Other ◽  
Hybrid Nanofluid ◽  
Hybrid Nanofluids ◽  
Tio2 Nanofluids

Due to the increasing demand in industrial application, nanofluids have attracted the considerable attention of researchers in recent decades. The addition of nanocellulose (CNC) with water (W) and ethylene glycol (EG) to a coolant for a radiator application exhibits beneficial properties to improve the efficiency of the radiator. The focus of the present work was to investigate the performance of mono or hybrid metal oxide such as Al2O3 and TiO2 with or without plant base-extracted CNC with varying concentrations as a better heat transfer nanofluid in comparison to distilled water as a radiator coolant. The CNC is dispersed in the base fluid of EG and W with a 60:40 ratio. The highest absorption peak was noticed at 0.9% volume concentration of TiO2, Al2O3, CNC, Al2O3/TiO2, and Al2O3/CNC nanofluids which indicates a better stability of the nanofluids’ suspension. Better thermal conductivity improvement was observed for the Al2O3 nanofluids in all mono nanofluids followed by the CNC and TiO2 nanofluids, respectively. The thermal conductivity of the Al2O3/CNC hybrid nanofluids with 0.9% volume concentration was found to be superior than that of the Al2O3/TiO2 hybrid nanofluids. Al2O3/CNC hybrid nanofluid dominates over other mono and hybrid nanofluids in terms of viscosity at all volume concentrations. CNC nanofluids (all volume concentrations) exhibited the highest specific heat capacity than other mono nanofluids. Additionally, in both hybrid nanofluids, Al2O3/CNC showed the lowest specific heat capacity. The optimized volume concentration from the statistical analytical tool was found to be 0.5%. The experimental results show that the heat transfer coefficient, convective heat transfer, Reynolds number and the Nusselt number have a proportional relationship with the volumetric flow rate. Hybrid nanofluids exhibit better thermal conductivity than mono nanofluids. For instance, a better thermal conductivity improvement was shown by the mono Al2O3 nanofluids than the CNC and TiO2 nanofluids. On the other hand, superior thermal conductivity was observed for the Al2O3/CNC hybrid nanofluids compared to the other mono and hybrid ones (Al2O3/TiO2).

A Theoretical and Experimental Investigation of Unidirectional Freezing of Nanoparticle-Enhanced Phase Change Materials

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Liwu Fan ◽  
J. M. Khodadadi
Keyword(s):  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Phase Change ◽  
Phase Change Materials ◽  
Solid Phase ◽  
Experimental Setup ◽  
Cold Plate ◽  
Numerical Predictions ◽  
Unidirectional Freezing ◽  
Measured Thermal Conductivity

Highly-conductive nanostructures may be dispersed into phase change materials (PCM) to improve their effective thermal conductivity, thus leading to colloidal systems that are referred to as nanostructure-enhanced PCM (NePCM). Results of a theoretical and experimental investigation on freezing of NePCM in comparison to the base PCM are presented. A one-dimensional Stefan model was developed to study the unidirectional freezing of NePCM in a finite slab. Only the thermal energy equation was considered and the presence of static dispersed nanoparticles was modeled using effective media relations. A combination of analytical and integral methods was used to solve this moving boundary problem. The elapsed time to form a given thickness of frozen layer was therefore predicted numerically. A cooled-from-bottom unidirectional freezing experimental setup was designed, constructed, and tested. Thermocouple readings were recorded at several equally spaced locations along the freezing direction in order to monitor the progress of the freezing front. As an example, cyclohexane (C6H12) and copper oxide (CuO) nanoparticles were chosen to prepare the NePCM samples. The effective thermophysical and transport properties of these samples for various particle loadings (0.5/3.8, 1/7.5, and 2/14.7 vol. %/wt. %) were determined using the mixture and Maxwell models. Due to utilization of the Maxwell model for thermal conductivity of both phases, the numerical predictions showed that the freezing time is shortened linearly with increasing particle loading, whereas nonmonotonic expediting was observed experimentally. The maximum expediting was found to be nearly 8.23% for the 0.5 vol. % sample. In the absence of a nanoparticle transport model, the mismatch of the cold plate boundary conditions, lack of accurate thermophysical properties, especially in the solid phase of NePCM samples and precipitation issues with 2 vol. % samples were addressed by improving the experimental setup. Through adopting a copper cold plate, utilizing measured thermal conductivity data for both phases and using 1, 2, and 4 wt. % samples, good agreement between the experimental and numerical results were realized. Specifically, adoption of measured thermal conductivity values for the solid phase in the Stefan model that were originally underestimated proved to be a major cause of harmony between the experiments and predictions.

Innovative Lime-Pozzolana Renders for Reconstruction of Historical Buildings

2011 ◽  
Vol 324 ◽  
pp. 372-375 ◽  
Author(s):  
Eva Vejmelková ◽  
Petr Máca ◽  
Petr Konvalinka ◽  
Robert Černý
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Compressive Strength ◽  
Diffusion Coefficient ◽  
Bending Strength ◽  
Moisture Diffusivity ◽  
Historical Buildings ◽  
Matrix Density ◽  
Lime Plaster ◽  
Water Sorptivity

Bulk density, matrix density, open porosity, compressive strength, bending strength, water sorptivity, moisture diffusivity, water vapor diffusion coefficient, thermal conductivity, specific heat capacity and thermal diffusivity of two innovative renovation renders on limepozzolana basis are analyzed. The obtained results are compared with reference lime plaster and two commercial renovation renders, and conclusions on the applicability of the particular renders in practical reconstruction works are drawn.

scholarly journals Applying Active Thermography in the Non-Destructive Investigation of Historical Objects/ Zastosowanie Termowizji Aktywnej Do Badań Nieniszczących Obiektów Zabytkowych

2015 ◽  
Vol 17 (2) ◽  
pp. 105-115
Author(s):  
Henryk Nowak ◽  
Paweł Noszczyk
Keyword(s):  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Heat Capacity ◽  
Building Envelope ◽  
Practical Application ◽  
Wall Model ◽  
Historic Building ◽  
Active Thermography ◽  
Historical Objects ◽  
Non Destructive

Abstract The paper pertains to the problem of historic building envelope investigation with the use of active thermography. Mainly emphasized is its application in the detection of different material inclusions in historic walls. Examples of active thermography in the reflective mode application and a description of the experimental investigation has been shown on a wall model with the inclusion of materials with significantly different thermal conductivity and heat capacity, i.e. styrofoam, steel and granite. Thermograms received for every kind of envelope are compared and analyzed. Finally, the summary and conclusion is shown along with the prospects of development and practical application of this kind of investigation in historic construction.

scholarly journals THERMAL TECHNICAL PROPERTIES OF ECOCOTTON/EKOVATOS ŠILUMINĖS TECHNINĖS SAVYBĖS

1998 ◽  
Vol 4 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Ivan Gnip ◽  
Vladislovas Keršulis
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Moisture Content ◽  
Specific Heat ◽  
Equilibrium Moisture Content ◽  
Statistical Treatment ◽  
Vapour Permeability ◽  
Building Enclosures ◽  
Technical Properties ◽  
Thermal Conductivity Λ

The purpose of this investigation was to determine thermal technical properties of Ecocotton (or Ecofibre)—thermoinsulating material produced from waste newspaper, boric acid and borax and to evaluate the most optimal areas for application of this material on the basis of this investigation. The density, antiseptic and antipirene quantities of the samples were determined according to [2], thermal conductivity at 25 °C—[4], equilibrium sorbative moisture content—[5], vapour permeability—[6]. The dependencies of dry Ecocotton thermal conductivity on its density and moisture content are given in Figs 1 and 2 as well as after mathematical statistical treatment using the regressive equations (1) and (2). These dependencies are linear. Ecocotton specific heat at 20–25 °C is 1040±100 J/kg · K. The determined equilibrium sorbative moisture content dependency on air relative humidity is given in Table 1 together with literature data about analogous Finnish material Selluvilla-SV. The difference between our and literature data is not significant. The vapour permeability results for Ecocotton are given in Table 2. This value is close to that for mineral wool products. The data about layeral and seasonal distribution of moisture content in Ecocotton and analogous Finnish product Selluvilla-SV used for insulating of attic floors are given in Tables 3, 4 and Fig 3. It was proved on the basis of these results and equilibrium moisture content calculations of building enclosures with insulating layer of Ecocotton, that the calculated equilibrium moisture content of Ecocotton is 9% (to mass). The calculated thermal conductivity and heat capacity coefficients of Ecocotton were calculated according to formulas (3) and (4). Experimental (specific heat C(), kJ/kg ·K: thermal conductivity λ(), W/m·K) and calculated (weight moisture content Ws %; thermal conductivity λ, W/m·K; heat capacity coefficient S, W/m2K; vapour permeability μl, mg/m·h·Pa) thermal technical values for 35, 50 and 75 kg/m3 density Ecocotton are given in Table 5. The most optimal areas for application of Ecocotton are insulation of building enclosures with ventilated air space.

Free and Forced Air Precooling of Perishable Food Products: Experimental Investigation

2020 ◽  
Vol 12 (4) ◽  
pp. 517-523
Author(s):  
Taliv Hussain ◽  
Shahzeb Ansari
Keyword(s):  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Heat Capacity ◽  
Thermal Diffusivity ◽  
Free Convection ◽  
Forced Convection ◽  
Food Products ◽  
Convection Cooling ◽  
Forced Air ◽  
Thermo Physical Properties

An experimental investigation has been performed in order to compare the thermo-physical properties of spherical and cylindrical shaped food products during forced and free convection cooling. The specific heat capacity increases with the increment in the percentage of moisture quantity as in cucumber, it was 96% and in banana, it was 74%. The thermal conductivity of cucumber was found to be 18.7%, 7.6%, 5.1% more than that of banana, orange, capsicum respectively in case of free convection cooling but it was 18.7%, 7.8%, 5.3% more than that of banana, orange, capsicum respectively in case of forced convection cooling. In free convection cooling, the value of thermal diffusivity of cucumber was noted to be 9.02%, 2.96%, 3.85% more than that of banana, orange, capsicum respectively while in case of forced convection cooling, it was 76.06%, 62.62%, 20.19% more than that of banana, orange, capsicum respectively.

Experimental investigation of the isobaric heat capacity and thermal conductivity of N2O4-no solutions in the liquid phase

1980 ◽  
Vol 38 (4) ◽  
pp. 395-399
Author(s):  
A. G. Dashuk ◽  
A. Zh. Greben'kov ◽  
A. B. Verzhinskaya ◽  
Yu. D. Il'yukhin ◽  
N. F. Gladkii ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Heat Capacity ◽  
Liquid Phase ◽  
Isobaric Heat Capacity
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