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Comparison of Density and Thermal Conductivity of the Prepared Boards with Other Insulating Material
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... signifies that the thermal diffusivity is inversely proportional to the density. Table 1 compares the measured apparent thermal conductivity and density of the developed boards with that of the standard products and published data on biodegradable thermal insulation. From the table, it can be observed that the developed boards recorded higher densities compared to synthetic product such as polyurethane, extruded and expanded polystyrene, but can be compared favourably with the boards from agro fibres such as oil palm, cotton stalk and narrowed leave cattail fibre boards. ...
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... Thermal diffusivity analysis of the sandwich composite panel was calculated based on data obtained from the thermal conductivity measurement, specific heat capacity value, and sandwich composite density. The thermal diffusivity of the sandwich composite panel was carried out based on following method by Abubakar [32]. Five types of composite samples were tested in this section. ...
... The measurement was carried out based on the transient plane source (TPS) thermal characterization method [28]. The thermal diffusivity value of a composite panel was calculated by dividing the thermal conductivity with density and specific heat capacity, as shown in Equation (7) [32]. ...
Massive generation of natural waste fiber from agricultural industries followed by improper disposal management might result in a detrimental effect on our ecosystem contributing to various types of environmental pollution. With the growing significance of climate change, an effort is being undertaken by utilizing natural waste fiber into eco-friendly insulation panels to reduce the environmental impact of buildings. In this research, a composite panel was developed from spent mushroom substrate (SMS) and empty fruit bunch (EFB) fibers via a sandwich technique. Five samples were made, each with a different fiber ratio (100 SMS: 0 EFB, 80 SMS: 20 EFB, 60 SMS: 40 EFB, 40 SMS: 60 EFB, and 0 SMS: 100 EFB) at density 0.8 g/cm3. Fourier transformation infrared (FTIR) Soxhlet extraction followed by thermogravimetric analysis (TGA) indicated that the SMS and EFB fibers were relevant for fabrication into a composite panel for thermal insulation. Thermal conductivity, thermal resistance, and thermal diffusivity values for these five composite samples were 0.231 to 0.31 W/(mK), 0.0194 to 0.0260 m2K/W, and 0.2665 to 0.3855 mm2/s, respectively. The flexural strength of the composite was at the range 15.61 to 23.62 MPa. These research findings suggest that the fabrication of a sandwich composite panel from SMS and EFB fiber is a promising alternative way to utilize natural waste fiber.
... The analysis follows the approach [19] who studied on the fluid flow in three side roughened and 1 side basically smooth duct and [20], who studied about computational investigation on thermal performance of solar air heater having roughness elements as really transverse wire on the 2-side absorber plat. The above 2 ducts actually have similar cross-section area of (W×H) with W >> H [20], demonstrating that the above 2 ducts kind of have similar cross-section area of (W×H) with W >> H [20], which definitely is significant. ...
... The analysis follows the approach [19] who studied on the fluid flow in three side roughened and 1 side basically smooth duct and [20], who studied about computational investigation on thermal performance of solar air heater having roughness elements as really transverse wire on the 2-side absorber plat. The above 2 ducts actually have similar cross-section area of (W×H) with W >> H [20], demonstrating that the above 2 ducts kind of have similar cross-section area of (W×H) with W >> H [20], which definitely is significant. In case of fully developed turbulent flow in a 4-sided very smooth duct, the friction factor really is written as follows [21], or so they essentially thought. ...
... The analysis follows the approach [19] who studied on the fluid flow in three side roughened and 1 side basically smooth duct and [20], who studied about computational investigation on thermal performance of solar air heater having roughness elements as really transverse wire on the 2-side absorber plat. The above 2 ducts actually have similar cross-section area of (W×H) with W >> H [20], demonstrating that the above 2 ducts kind of have similar cross-section area of (W×H) with W >> H [20], which definitely is significant. In case of fully developed turbulent flow in a 4-sided very smooth duct, the friction factor really is written as follows [21], or so they essentially thought. ...
Solar air heater is used for agricultural grain products drier, curing of industrial products and for other systems requiring low grade thermal energy. Their usefulness and quantitative energy collections has been limited. This is because of low thermal efficiency with primarily as a result of low convective heat transfer coefficient, between the absorber plate and air leading to higher plate temperature. This results greater thermal energy losses. Experimental investigation has been conducted to study heat transfer enhancement by using small diameter wire ribs on absorber plate of solar air heater duct, with the roughened wall exposed to the glazing side while the remaining 3 walls were insulated. The roughened wall has relative roughness height (e/Dh) 0.0135 - 0.0406, relative roughness pitch (p/e) 10 - 20, rib height 0.5 - 1.5 mm, expanded metal mesh (L/e) 25 - 75, Short way mesh (S/e) 15 - 45, angle of attack 45° for inclined configuration, duct aspect ratio of 12 and the air flow rate corresponds to Reynolds number between 2,000 to 18,000. It has been found that the heat transfer coefficient could be improved by a factor up to 2.2 and the friction factor had been found to increase by a factor of 1.2 times that of the smooth duct. The investigation emphasized that the secondary flow rolling along the inclined ribs is responsible for higher heat transfer rates. Thermal efficiency increased from 50.58 - 65.75 %. Finally, correlation is developed for both Nusselt number and friction factor using sigma plot software, which can be selected by the designer for a given operating condition. HIGHLIGHTS At the moment agricultural products are spoiled due to poor dryer A solar air heater with expanded metal mesh roughened solar collector is designed, manufactured and experimental test is conducted An efficient solar dryer is obtained GRAPHICAL ABSTRACT
... The tests confirmed good buckling strength and thermal insulation when an integrated thermal protection system was effective. Abubakar, Raji, and Abdulsalam Hassan (2018) aimed their research to develop an innovative thermal insulation board from the leaves and bark fibers of Camel's foot (Piliostigma Thonningii L.) and also investigated the water absorption, density, specific heat and thermal conductivity, and thermal diffusivity. A comparative analysis was also made and found these new boards have low values of thermal behavior and can be used as an external building component. ...
In general, to regulate the indoor room temperature, the heating and cooling of a building require more energy for active heating and cooling devices other than the energy consumption of other electrical, electronic household devices. The external wall in a building plays a vital role in determining the resistivity against the heat loss or gain. Previous studies reputed that the temperature inside the building was regulated using high thermal mass. But, now with the advances in construction practices, thermal insulation is one of the efficient technologies used for providing indoor comfort with its properties. Insulation for heat is to provide a layer of insulation materials which would curtail the heat gain or loss, which minimizes the power consumption of heating or cooling devices. Commercially a lot of insulation materials are used with high performance in thermal resistance. There is more scope to develop a cost-effective thermal insulating material that possesses excellent performance with less environmental impact. In this review paper, the performance of the different thermal insulation composites used for thermal insulation of exterior walls of a building is presented. The influence of the optimum thickness of the material in saving energy is another vital element to be discussed for the insulation composites. The economic and environmental impact of the insulation composites are elaborated with performance parameters and material properties.
... In the European Union (EU), the building sector is responsible for over 40% of overall energy consumption, which makes it a significant contributor to CO 2 emissions [1][2][3][4]. Due to the rising energy consumption of buildings (residential/commercial), increased prices of fossil fuels and its effect on global warming, energy saving through the use of thermal insulation is regarded as an effective and efficient method [5,6]. Efficient thermal insulation is a highly relevant topic [7][8][9], as highlighted by the fact that in the EU the heating of living space corresponds to the main use of energy in houses (64% of total energy consumption in houses) [10,11]. ...
... In the same manner, the regression dependence of thermal conductivity TC PE (perpendicular to the panel s plane) was calculated as a function of particle size PS and density ρ for perpendicular board direction in the form (5) TC PE = 11.0 × 10 −5 × ρ + 3.65 × 10 −4 × PS + 0.0390 (5) By means of multiple regression, the sensitivity coefficients of particle size PS and density ρ on thermal conductivity in both parallel and perpendicular directions were calculated also, which are shown in Table 4. This research showed a highly significant (p < 0.001) influence of bulk density on the thermal conductivity of boards in all cases. ...
... However, the ratio of density slopes for parallel direction vs. perpendicular direction is equal to 0.737 for Equations (6) and (7) and 0.718 for the model with particle sizes PS. The difference between these two ratios is equal to 2.55%, which is the result of the different particle sizes in Equations (4) and (5). The average absolute part for the density-particle size model for both directions is equal to 0.0373 W.m −1 .K −1 and for the density only model equal to 0.0355 W.m −1 .K −1 , which means that the deviation then is equal to 5.15%. ...
The effects of using 100% larch bark (Larix decidua Mill) as a raw material for composite boards on the thermophysical properties of this innovative material were investigated in this study.
Panels made of larch bark with 4–11 mm and 10–30 mm particle size, with ground bark oriented parallel and perpendicular to the panel’s plane at densities varying from 350 to 700 kg/m3 and bonded with urea-formaldehyde adhesive were analyzed for thermal conductivity, thermal resistivity and specific heat capacity. It was determined that there was a highly significant influence of bulk density on the thermal conductivity of all the panels. With an increase in the particle size, both parallel and perpendicular to the panel´s plane direction, the thermal conductivity also increased.
The decrease of thermal diffusivity was a consequence of the increasing particle size, mostly in the parallel orientation of the bark particles due to the different pore structures. The specific heat capacity is not statistically significantly dependent on the density, particle size, glue amount and particle orientation.
... This is possible, because larger void spaces are avenues for absorption and retention of more water compared to smaller ones. Similar trend was observed in the case of thermal insulation board developed from leaf and bark ibers of Camel's foot (Abubakar et al., 2018). ...
Due to the problems militating against solid-waste management in developing countries, the disposal of sugarcane leaves is majorly done by burning in an open space. Such practice usually results in environmental pollution due to generation and emission of carbon dioxide. There is need to look into a scientific way of reducing the waste in question and enhance its use in the production of environmentally-friendly, inexpensive, and value-added material. In this work, thermal conductivity (k), bulk density (\(\rho\)), specific heat capacity (C), thermal diffusivity (λ), thermal absorptivity (⍺), thermal inertia (e), water absorption (W.A), flexural strength (\(\sigma\)), and compressive strength (CS) were investigated for compressed boards made of sugarcane (Saccharum Officinarum) leaves. The mean with standard error values obtained for k, \(\rho\), C, λ, ⍺, e, W.A,\(\sigma\), and CS were (0.0481 ± 0.0004) Wm−1 K−1, (253.558 ± 2.459) kg.m−3, (2140.930 ± 1.356) Jkg−1 K−1, (8.867 ± 0.024) × 10−8m2 s−1, (20.252 ± 0.004) m−1, (161.633 ± 1.421) Jm−2 K−1 s−½, (90.123 ± 0.164) %, (0.263 ± 0.004) Nmm−2, and (0.152 ± 0.006) Nmm−2, respectively. Observably, these values compare favourably with those of already-known conventional ceiling panels. Thus, sugarcane leaf is a potential eco-friendly raw material for the production of thermal insulation boards that are suitable for use as a ceiling for naturally cooled building design, especially, in tropical regions. Doing so can help to minimise the adverse effect resulting from the practice of its disposal by open burning method.
... According to many researchers, in the future, energy demand will only increase [15][16][17][18][19], work to improve the efficiency of structures for thermal insulation of buildings and structures will be increasingly relevant from the point of view of energy saving. Rising prices for thermal energy is also a significant basis for the development of new thermal insulation materials. ...
This paper solves the problem of recycling irretrievable waste spinning flax and cotton. This plant waste is incinerated or sent to landfill. It is proposed to use plant waste as a filler for building materials for thermal insulation purposes. New thermal insulating materials based on plant waste are manufactured using the technology of soft fibreboard wet production method. Synthetic thermosetting or inorganic binders are used as the matrix of the composites. The article presents the results of an experimental determination of the coefficient of thermal conductivity of plate materials from irretrievable spinning waste of flax and cotton fibers. Composites based on flax waste filler have a lower value of thermal conductivity coefficient than for cotton waste plates. The results of determining the thermal conductivity coefficient of composite boards based on spinning flax and cotton showed that the developed material can be used as an internal thermal insulating layer of enclosing structures.
