Papers by Keyword: Insulation

Abstract: The work investigates the effect of additives to the primary material of a current-carrying conductor on the heating temperature of an electrical wire, exemplified by a single-core aluminium wire with single-layer polyvinyl chloride insulation. It establishes the dependencies between the wire's heating temperature and its operating time under load currents that are lower, close to, and higher than the permissible levels set by regulations. The effect of chromium, vanadium, and titanium additives to the primary material of a current-carrying conductor on the wire's heating temperature during operation is also evaluated. Even small amounts of additives (less than 0.1%) to the primary material of a current-carrying conductor can affect the heating temperature of the loaded wire. Chromium additives have the most effect, while titanium additives have the least effect. The study demonstrates that during operation, a loaded electrical wire heats the least if the primary material of its current-carrying conductor has none of the additives considered in the article.

Abstract: This study aims to evaluate the performance of MPC building envelopes across Morocco's climatic zones and enhance occupant thermal comfort without the use of heating or cooling systems. The construction typology examined is residential housing. Dynamic thermal simulations were conducted using Design-Builder software, enabling thermal-aerodynamic coupling to account for natural ventilation effects. Key findings reveal that the thermal inertia of MPC walls effectively stabilizes indoor temperatures in winter by dampening external temperature fluctuations, thereby reducing heating demands. However, in the summer, particularly during extreme heat events, this same thermal inertia hinders heat dissipation, resulting in increased indoor discomfort. Simulation results indicate that adding insulation to MPC walls improves indoor comfort, as demonstrated by a reduction in the Predicted Percentage of Dissatisfaction (PPD) index by up to 20% in winter and up to 10% in summer. This research underscores the potential of MPC structures as a sustainable building solution (R ≈ 0.62 m²K/W) that integrates local materials, reduces CO₂ emissions, and addresses the thermal comfort needs of Moroccan households across diverse climates, in compliance with Morocco’s Thermal Construction Regulation (RTCM).

Abstract: End-of-life LCD screens from various waste steam have been used to formulate foam glass, aiming for use as light weight, high compressive strength, and insulation purposes. Via conventional ball milling, the foam glass powder was mixed with a binder and fabricated through compaction under 5-10 MPa using stainless steel press moulds to give green samples in cubic and plate shapes. Firing the samples at 1000 – 1050 °C for 0.5-4 hours allowed the construction of foam glass structure, giving low densities of 0.15-0.23 g/cm³. Additions of cordierite, calcium carbonate, graphite and borax determined the phases and composition of the final recycling products. Cristobalite appeared as the main phase along with anorthite were found to give high compressive strength of 1.10-4.22 MPa to the foam glass. The foam glass possessed thermal conductivity in a range of 0.1004-0.1183 W/m K, which can be used for insulation purposes. Different foam glass formulation and geometries required different firing temperature and time to acquire suitable foam glass structure for specific purposes of compressive and thermal insulation properties.

Abstract: The present work concerns an experimental study of the utilization of insulation and phase change material PCM in building structures. It particularly presents an efficient heating system modulated with thermal insulations and phase change materials where an appropriate experimental setup is devised to help in making energy management possible. The experimental setup consists of insulated and non-insulated room models that enable direct observation of different heat transfer results between a well-insulated room with PCM (paraffin wax) and a non-insulated room. The integrated heating-insulation-PCM set-up proved that it can work toward a more comfortable and efficient system where energy bills are 74% lower with an average improvement factor reaching 50% in comparison with the non-insulated room model.

Abstract: The research on the nanofluid as an alternative transformer oil has been widely attracted the concern of many researchers as the effectiveness as insulation and cooling agent of the existing transformer oil is not achieved satisfactory to accommodate the rising demand of high voltage rate. In this study, nanofluid with a nanomaterial, Carbon Nanotube (CNT), with and without Polyvinylpyrrolidone (PVP) has been formulated, and their AC breakdown voltage of the mineral oil (MO) according to IEC 60156 standard has been characterized. The concentration of CNT study is 0.005, 0.01, 0.015 and 0.02 g/L. It is found that the optimum concentration in nanofluids without PVP is 0.005g/L of nanofluids concentration with the highest breakdown voltage 53.52. In comparison, the highest breakdown voltage for nanofluids with PVP is 33.4kV at 0.01g/L. The existence of PVP in the nanofluids seems not significantly affect the dielectric performance of the degradation of the nanofluid from 5% to 43%. Hence, nanofluids with CNT addition are proofed as a good additive in insulation oil for future transformer applications.

Abstract: The erstwhile transformer oil material, for all these periods of more than two centuries, has been championing liquid dielectrics, for machines’ cooling and insulation purposes. However, its use has detrimental and attendant consequences on global terrestrial and aquatic habitats, industries and global warming. Palm oil (Elaise Guinensis Eg; and/or Elaise Oleifera Eo) is presently posing a great challenge to liquid hydrocarbon in the operation of transformers. Despite the ease in availability of mineral oil today, especially for oil producing nations, this paper aims at unveiling its several underscores and analyses of the viscosity, flash point, density, neutralisation (acidic value) number, electrical resistivity, and breakdown voltage (BDV) results of the respective mineral and palm oil samples. Palm oil’s test results values of approximately, 244OC, 55kV and 0.004 mgkOH/gm of oil, was recorded, respectively for the flash point, breakdown voltage (BDV) and acid neutralisation index, as compared with corresponding mineral oil’s values of 142OC, 59kV and 0.004 mgkOH/gm. The results obtained favoured the use of palm oil than the mineral oil for transformer’s operation.

Abstract: This paper studies the electrical efficiency of carbon nanotubes (CNT) with nanosized diameter inserted into palm-based oil at various concentrations (0, 0.0125, 0.025, 0.0375, 0.05, 0.125, 0.25 and 0.5 g/L). Dispersion methods, including sonication and drying process were systematically applied for producing stable CNT nanofluids. Several parameters such as electrical properties (AC breakdown voltage) and dielectric properties (dissipation factor, relative permittivity and resistivity) were measured accordingly based on IEC 60156 and IEC 60247 international standards. The test results reveal that the higher concentration of CNTs dispersed in palm oil, the lower AC breakdown voltages produced. At 0.5 g/L concentration, the average of 50 breakdown was 22.30 kV, which is 72.33% decrement compared to palm oil without any nanofiller. Besides, the permittivity and resistivity of CNT nanofluids decrease as concentrations increased, while dissipation factor increases along with CNT concentrations. In order to further support this indication, Raman analysis is measured to relate the behavior of AC breakdown voltages and chemical structure of CNT nanofluids. Based on the Raman spectra at 2800-3200 cm^-1 region, it is shown that the value of total unsaturated fatty acid and total fatty acid decreased as concentrations of CNT increased. This occurrence directly influences the degradation performance of AC breakdown voltages.

Abstract: This research aims to study mycelium-based composites (MBC) by assessing their performance as foam-like wall insulation material. Various substrates have been selected to get optimized performance of the composite. Results showed that a prolonged growing period arose a denser mycelium outer layer in MBC, which rendered better water resistance due to the hydrophobicity of mycelium. Thermal conductivity and mechanical properties are highly dependent on substrate choices than other parameters of MBC, which coincided with the literature. Additionally, influences of accelerated aging test and moisture buffer capacity of MBC were first studied in this research. The results indicated that MBC not only maintained good functional performance after the accelerated aging test (i.e. drying and wetting cycles) but also constituted good moisture buffer capacity. This means that MBC has key material essences to apply as internal wall insulation material and become one of the layers in vapor-permeable building envelope systems to passively regulate indoor relative humidity and thermal comfort.

Abstract: Energy saving is one of today’s biggest challenges. Since the construction industry is very energy intensive, there is a question of drastic reduction of energy consumption in all types of buildings. There are different approaches to this issue, but ultimately there is a need to create materials that have high thermal resistance.

Abstract: The dielectric strength of insulating liquids of transformer acts an important parameter in the operation of transformer. Thus, great interest and many studies have been extensively done to improve the dielectric strength. One of study is the introduction of nanoparticle in the transformer oils. Study of the nanoparticles for the last few years had been found that, it can be dispersed in the transformers oils to be nanofluids and directly enhance the transformer performance. In this study, an investigation has been carried out to focus on the effect of silicon carbide (SiC) nanoparticle to AC (alternating current) breakdown voltage of the Refined, Bleached, and Deodorized Palm Oil (RBDPO). AC breakdown test have been conduct according to the standard of the IEC 60156. Besides that, a number of parameters will be evaluated such as dielectric dissipation factor (tan δ), relative permittivity (ε), and resistivity (ρ). Based on the results of the experiment, the electrode gap at 2.5 mm having the highest AC breakdown voltage compared to the other electrode gap which are 1.0 mm, 1.5 mm and 2.0 mm. Furthermore, doping with different concentrations of the silicon carbide (SiC) in Refined, Bleached, and Deodorized Palm Oil (RBDPO) found decreasing of AC breakdown voltage from 52.09 kV (without SiC) to 45.3 kV for 0.001 g/L, 43.2 kV for 0.003 g/L and 40.1 kV for 0.005 g/L respectively.