K-type Thermocouples Research Articles

Assessment of Land-sat Satellite Images used to calculate Land Surface Temperature(LST): A case study in Adhamiya Baghdad

With the help of this study, a method for extracting temperature of the land surface (LST) using data from thermal band 10 of LAND-SAT9 collection 1 levels -1 and collection 2 level 2 is described. This method uses satellite data from thermal infrared sensors (OLI & TIRS). This research aims to estimate the LST over the AL-Adhamiya area on the image date 02/20/2023 to retrieve and compare the (LST) including real-time measurements made while taking the images using an infrared thermometer camera, readings were made in direct contact with the object using ( K-type thermocouple ). The findings demonstrated that the LST varies depending on whether there is vegetation, bare soil, asphalt, or a residential area.=11 C°, 14-16 C°,13.9- 15.5 C° and 19.1 – 20.7 C° resprctivly. This study compares the association between different forms of land cover and (LST) and assesses how well land cover temperature amounts are described using LAND-SAT-9 data.

Effect of welding mode on selected properties of additively manufactured AA5087 aluminium alloy parts

Wire and arc additive manufacturing (WAAM) is a popular direct energy deposition (DED) method for producing large-scale metallic components. The main advantages of the technique are a high deposition rate and low cost. Furthermore, the utilization of the WAAM is prevalent in the aerospace industry. The AA5087 aluminium alloy with 4.5 wt.% of magnesium has been investigated because of its excellent properties. The present research deals with the study of thermal cycles and fields developed in the alloy during additive manufacturing with two different Cold metal transfer (CMT) modes, namely conventional (CMT) and cycle-step (CMT-CS). The welding system was equipped with a Fronius TransPulse Synergic 3200 CMT power source, a Fanuc Arc Mate 1000iC 6-axes robot with an R 30iA control unit, a welding torch, and a 1-axis positioner. The AA5087 aluminium alloy welding wire with a diameter of 1.2 mm was deposited onto the AA5083 aluminium alloy plate with dimensions of 70 mm x 200 mm x 3 mm during the experiment. The thermal cycles were documented using an Ahlborn Almemo 5690-2 measuring station equipped with K-type thermocouples. The thermal fields were monitored with a FLIR E95 thermography camera. The results showed the evident influence of arc mode on the temperatures developed in manufactured aluminium alloy parts during the process of WAAM.

Characteristics of Residence Time of the Torrefaction Process on the Results of Pruning Kesambi Trees

The excessive use of Kesambi (Schleichera oleosa) tree stems threatens the sustainability of Kesambi plants since it takes several decades for them to regenerate new stems. This research aims to determine the characteristics of torrefied Kesambi tree pruning. The used reactor has a diameter of 400 mm. An iron basket is positioned 100 mm above the reactor base, holding the material within an aluminum cylinder. The reactor temperature is maintained at 300°C using a K-type thermocouple sensor. A heater is placed near the reactor base and covered. The characteristics of the semi-charcoal biomass product are identified, including mass yield, water absorption capacity, moisture content (D3173, 2013); ash content (ASTM D1102-84. Standard Test Method for Ash in Wood, 2013); volatile matter (%) (ASTMD3175, 2011); and fixed carbon (%) (ASTM, 2013). The color of the leaves and the pruned Kesambi tree changes from brown to black as the residence time increases. The results of pruning the Kesambi tree at different torrefaction residence times indicate a decrease in mass yield with an increase in residence time, with the lowest mass yield observed at a residence time of 20 minutes. The water absorption capacity of torrefied Kesambi tree pruning material is found to be between 0.65% and 0.675%, or less than 1% and higher heating value (HHV) prediction 29.0750 MJ/kg.Keywords: Kesambi, Pruning, Residence, Time, Torrefaction

Numerical Study of the Cold Metal Transfer (CMT) Welding of Thin Austenitic Steel Plates with an Equivalent Heat Source Approach

The CMT (cold metal transfer) arc welding process is a valuable joining method for assembling thin sheets, minimizing heat transfers, and reducing subsequent deformations. The study aims to simulate the CMT welding of thin stainless-steel sheets to predict temperature fields and deformations. Both instrumented tests and numerical simulations were conducted for butt-welding of sheets with a thickness of 1 to 1.2 mm. Weld seam samples were observed to identify equivalent heat sources for each configuration. The electric current and voltage were monitored. Temperature measurements were performed using K-type thermocouples, as well as displacement measurements via the DIC (digital image correlation) technique. Thermomechanical simulations, considering phase changes and the actual seam geometry induced by filler material, were conducted using an equivalent heat source approach. A unique heat exchange coefficient accounting for thermal losses was identified. By incorporating these losses into thermal calculations, a good agreement was found between measured and calculated temperatures. Mechanical calculations allowed for the recovery of the horse saddle form after actual welding, with a relative difference of less than 10% in angular distortion between calculated and measured values.

Integrated design and fabricate of high sensitivity built-in thin-film thermocouple temperature measurement tool

Abstract Cutting temperature is playing a key role in evaluating the cutting process, which significantly affects the tool wear and the quality of the workpiece. Aiming at the problems of low precision, low aging, and poor stability of cutting temperature measurement on the front tool face, an integrated design and production scheme of a high sensitivity built-in wireless temperature measurement tool was proposed. The temperature distribution position on the front tool face was analyzed with 3D finite element simulation software, and the thermal contact position of the main and secondary film thermocouples was determined. SiO2 insulated films and NiCr/NiSi film thermocouples were prepared on the front tool surface by femtosecond laser micromachining, electrolyte-plasma polishing, plasma enhanced chemical vapor deposition and magnetron sputtering, and a static calibration experiment system for sensitivity and accuracy of the temperature measuring tool for the film thermocouple was established, and Seebeck coefficient of the film thermocouple was obtained. According to the actual cutting conditions, the wireless temperature measuring system of the thin film thermocouple tool was built and the field cutting test was carried out to obtain the influence law of different cutting parameters on the cutting temperature, and further verify the feasibility of the thin film temperature measuring sensor. The research results show that: Seebeck coefficients of the two kinds of thermocouples prepared by the NiCr/NiSi thin film thermocouple temperature measuring tool are 34.97 μV/°C and 34.96 μV/°C, and the slope of the temperature data fitting curve is 1.00398 and 0.997475, respectively. The linear correlation coefficient R2 is close to 1, which is close to the standard K-type thermocouple, which shows good sensitivity and accuracy. At the same time, the temperature measurement results are close to the commercial standard K thermocouple, and the error is less than 5%, indicating that the developed film thermocouple has a high measurement accuracy and can meet the needs of temperature measurement. Actual cutting test is carried out with developed wireless temperature measuring device of thin film thermocouple, which shows this device can meet the requirements of tool temperature measurement, and the feasibility of thin film temperature measuring sensor is further verified. The research provide technical reference for industrial intelligent manufacturing in order to realize the wireless measurement of cutting area temperature of tool front.

Thermal analysis of a turbulent wall jet over an adiabatic wavy surface

The impact of wavy wall amplitude on the turbulent characteristics of a wall jet has been investigated experimentally, where the wavy wall is given an adiabatic condition. In the experimental study, the mean and turbulent velocity are measured using a constant temperature anemometer manufactured by Dantec Dynamics. For temperature measurement over the wall and within the flow domain, the FLIR camera and k-type thermocouple are used, respectively. For the current study, uniformly heated at △T0 = (T0 − T∞) = 30 ± 1.2 0C with a Reynolds number of 15,000 is utilized to flow over a sinusoidal wavy wall (y = A*sin (ωx)), where “A = Amplitude ⁄ a” is the amplitude normalised by the nozzle height “a". The nozzle height is 20 mm and to maintain the Reynolds number 15,000 at the inlet, velocity is set at 10.95 ± 0.36 m ⁄ s. The amplitude of the wavy wall is varied between 0.2 and 0.6 and the results are compared to those of the plane wall jet. The current problem is also numerically solved using the k − ε RNG and k − ω SST models. Based on the results, it is concluded that the k − ε RNG model predicts the wavy wall results quite well. It is also discovered that the thermal self-similar profile deviates from the Gaussian curve at the crest of the wavy wall. The influence of the wavy surface on the thermal characteristics of the turbulent wall jet is more pronounced in the near flow field. It is observed that the bottom wall temperature, fluctuating temperature and turbulent heat flux decrease with the increase in amplitude. This indicates that for the higher amplitude, the turbulence increases, which increases the intermixing of jet fluid with the colder ambient fluid. The present results can be used as a benchmark for validating numerical models working in this area.

Analysis of interfacial heat transfer coefficients in squeeze casting of AA6061 aluminum alloy with H13 steel die: Impact of section thickness on thermal behavior

A step die made of H13 steel was utilized in this investigation cast aluminum alloy AA6061 at a pressure of 95 MPa in sections measuring 3 mm, 6 mm, 9 mm, 12 mm, and 15 mm in thickness. Surface temperatures during the squeeze casting process, as well as temperatures at distances of 3 mm, 6 mm, and 9 mm from the inner wall of the die, were recorded using K-type thermocouples. Utilizing the inverse method to solve 1-D heat conduction equations, we successfully determined the interfacial heat transferring coefficients (IHTC) and the interfacial heat flux (IHF) of the cast and die surface. The calculations revealed that with the commencement of squeeze casting, there was a significant rise in the IHTC for each of the five sectional steps. These IHTC reached their peak before they began to decline. The peak range of IHTC incrementally increased with the section thickness, from the 3 mm of Step 1 up to the 15 mm of Step 5. Moreover, the rate at which the IHTC reached its peak and then stabilized at a low level was slower for steps with greater thicknesses.

Experimental study of the effect of the concentration of water/polyalkylene glycol solutions on heat transfer in steels subjected to quenching

In this work, the heat transfer coefficients were determined utilizing an experimental study for cooling a 15B35H boron steel, using aqueous solutions of polyalkylene glycol (PAG) as a cooling fluid. A cooling tank was designed and built to allow the fluid recirculation, where the effect of agitation and the PAG content in a concentration range of 2%–6% vol. were analyzed. The thermal histories of cylindrical probes instrumented with K-type thermocouples were obtained, and the heat transfer coefficients associated with the types of refrigeration were calculated, solving the IHCP. The results show the presence of two maximum surface heat flux denominated q1max for the low-temperature range and q2max for the high-temperature range. Getting higher q1max and low q2max is desirable to avoid distortion and cracking. It was found that 4% PAG exhibits a slight variation of heat flux values in both low and high-temperature regions, regardless of the degree of agitation, maintaining values of about 3 MW·m−2 for q1max and 5.5 MW·m−2 for q2max. In this case, q2max is higher than q1max, leading to higher cooling rates in the martensitic transformation zone, increasing the risk of distortion and cracking. In the cases of 2 y 6% PAG, agitation affects q1max ranging from 2.5 to 6 MW·m−2, and for q2max from 4 to 6 MW·m−2, where q1max is always higher than q2max, providing better conditions for quenching.

TEMPERATURE CORRECTION METHOD OF RADIATION THERMOMETER BASED ON THE NONLINEAR MODEL FITTED FROM SPECTRAL EMISSIVITY MEASUREMENTS OF Ni-BASED ALLOY

Accurate temperature monitoring of heat transfer tube is crucial for safe and efficient operation of nuclear power plants, and radiation thermometer is a common method used for this purpose. This paper thoroughly introduces the measurement principle of the radiation thermometer with an operation wavelength range of 8-14 μm. The spectral emissivity of Ni-based alloy DD6 under argon condition is measured using an emissivity measurement setup equipped with a Fourier-transform infrared (FTIR) spectrometer. By integrating the spectral emissivity in the working wavelength range, the spectral band emissivity can be calculated to enhance the accuracy of calculation results obtained by radiation thermometer. And curve of the spectral band emissivity with temperature can be accurately described by the nonlinear model. The radiation and corrected temperatures are compared with the temperatures obtained by a K-type thermocouple to verify the availability of the spectral band emissivity obtained by fitting the nonlinear model. The temperature comparison results demonstrate that the corrected temperatures are closer to the true temperature than the radiation temperature, with a maximum temperature deviation of only 4.38°C. The combined relative uncertainty of true temperature measurement by the radiation thermometer at temperatures of 200, 300, 400, and 500°C is less than 3.60%.

Temperature fields analysis and heat dissipation structure design of an film capacitor in new energy vehicle

The high-temperature resistance performance of film capacitors in motor controllers faces greater challenges with the development of high voltage and high power density of new energy vehicles (NEVs). In this study, a typical film capacitor is taken as the object of research; simulations of temperature fields and experiments on temperature rises are conducted. Additionally, a heat dissipation structure is designed to enhance the high-temperature resistance performance of the capacitor. Firstly, the temperature field distributions of the capacitor under different ripple currents and ambient temperatures are analyzed using ANSYS electro-thermal coupling simulation. Then, under the same operating conditions, experiments on the temperature rises are conducted on the capacitor, which is installed with K-type thermocouples to verify the accuracy of the electro-thermal coupling simulation. Furthermore, an external heat dissipation structure consisting of a micro-channel liquid cold plate is designed for the capacitor, and the effectiveness of the external cold plate is verified through electro-thermal coupling and FLUENT simulations. It is found that under the operating conditions of 85 ?C ambient temperature and 175 A ripple current, the maximum temperature of the capacitor with the external cold plates decreases by 46.08% compared to the original capacitor. The results indicate that the external cold plates effectively improve the high-temperature resistance capability of the film capacitors in electric vehicles.

Comparative analysis of time dependent temperature profiles of hydrating mass concretes of different mix ratios

In mass concrete, heat due to cement hydration in most cases is not easily released and is otherwise confined within its core. Consequently, mass concrete may exhibit quite remarkable increase in temperatures internally depending on majorly the vicinity temperature and the proportion of cement in mixture ratio. When the surface tensile stresses resulting from temperature difference between its core and surface exceeds the strength of the concrete, cracks could develop at the surface. Two mass concrete blocks of dimensions 1.10 m × 1.10 m × 1.10 m each and mixes of 1: 2: 4 and 1: 3: 6 with constant water cement ratio (w/c) of 0.60 were used in the study. Type-K thermocouples were used to monitor the temperature variance in mass concretes. BK Precision 710 temperature meter dual input was used to determine the temperature readings at time intervals. Thermometer was used to measure the environment temperatures within the vicinity of the mass concretes. Generally, the trends of the temperature profiles exhibit an initial uniform temperature which rises to peak values at 24 hours of concrete placement and then declined to constant temperature at mostly 120 hours and beyond. The sole source of heat in hydrating concrete is the cement paste, and higher cement content leads to higher quantity of heat release. Therefore, the mass concrete block of mix ratio 1:2:4 exhibited higher quantity of heat release than that of 1:3:6 especially at the core.

Evaluation and Comparison of Thermal Changes in the Pulp Chamber in Different Inter Proximal Reduction Techniques: An In-vitro Study

Introduction: Interproximal reduction (IPR) is a common orthodontic treatment procedure that is used which involves tooth reduction, anatomic recontouring, and protecting permanent teeth proximal enamel surfaces. Sheridan described the air-rotor stripping technique as an alternative to extraction in borderline cases. Though there are many studies, it was not clearly differentiated regarding the pulpal temperature changes during IPR.
 Materials and Methods: In this in vitro study, 63 extracted human premolar teeth were randomly assigned to three groups (n=21). Group-1 (Strauss diamond stripping bur) at high speed above 20,000 rpm, Group-2 (Manual Handheld metal stripper). Group-3 (Strauss diamond stripping disc) at a low speed below 15,000 rpm. The average mean temperature is assessed for each tooth during various techniques using K-type thermocouple. During the procedure, the thermometer display was covered, and the temperature was revealed after all the stripping procedures had already been performed. Data were analyzed using IBM SPSS version 20 software. Descriptive statistics, one way analysis of variance with Tukey’s post hoc tests were done to analyze the study data.
 Results: The mean rise in temperature was highest with disc & micromotor (4.3ºC) followed by airotor & bur (4.02ºC) and manual method (2.52ºC) (p ≤ 0.05).
 Conclusion: There was an increase in the pulpal temperature using diamond stripping disc with micromotor followed by the airotor and bur, manual hand held stripping.

An Experimental Investigation of the Performance of a Solar Heater under Climate Conditions of South of Iraq

In general, solar water heating system can be described as a beneficial device for heating water by the utility of incident solar radiation. In the present study, an experimental solar water heater was constructed in Misan City, south of Iraq. The constructed experimental unit is a box of glass with a width of 40 cm. To measure temperatures of the experimental unit 7 K-type thermocouples were used. Three different inclination angles were investigated. The results showed that in the month of January, temperature of the solar water heater reached around 70 °C with an inclination angle of 37°. Furthermore, it was conducted that for the investigated period (January), temperatures reached the maximum at around 14 p.m. and then there was a decrease in the temperature. Moreover, it was concluded that the height of the solar water heater has a significant influence on the temperature.

Numerical Modelling and Experimental Validation of Dissimilar Aluminium 2014 and 7075-SiC Composite by Friction Stir Welding

In this study, a dissimilar AA7075+25% vol. SiC composite and AA2014 was selected to understand the effect of temperature distribution in the HAZ region with a maximum reinforcement of 25% vol. of SiC in the AA7075 matrix. The friction and slip-stick mechanism were combined in the numerical 3D model and simulated with different process parameters. The peak temperature of the dissimilar aluminium AA7075+25% vol. SiC composite and AA2014 was simulated and predicted as 860 K maximum and 728 K minimum, respectively. The experimental results were obtained in real-time FSW interfaced with a calibrated K-type thermocouple in a DAQ system. The thermocouple was placed at 15 mm, 20 mm, and 25 mm from the weld centerline to obtain experimental temperatures that were extremely close to the numerical peak temperature. The error percentage between the experimental values and simulation values ranged from 2.38% to 13.41%.

Performance of Heat Pipe with Different Working Fluid on Harvesting Wasted Heat Energy at Air Cooled Split Unit

These days, life would not be comfortable without air conditioning which leads to high power consumption due to air conditioning and subsequently increases the carbon footprint. In this research, verification was done on the capability of increasing superheat to improve the performance of the air-cooled split unit and the effect of power consumed by the air conditioning system. The superheat was increased by the heat harvested from the condensing unit of the air-cooled split unit by using a heat pipe. The heat pipe was charged with water, R134a, and R600a with a 100% filling ratio and 90 and 70 inclination angles. K-Type thermocouples, pressure gauges, and power meter were used in data collection. According to data analysis, water with a 90 inclination angle of heat pipe showed the best performance compared to other fluids because of its ability to increase superheat by approximately 32% compared to R600a which increased only approximately 6.5% compared to normal conventional air conditioning. However, it demonstrated that a rise in the superheat at the suction line and a rise in the Coefficient of Performance cannot guarantee a fall in energy usage. This was due to an increase of superheat by the water heat pipe at 90 angle inclination indicating approximately a 28.8% increase in power consumption.

Skin temperature of the knee was effectively reduced when using a new continuous cold-flow cryocompression device: a randomised controlled crossover trial

ObjectiveTo determine which temperature settings on a new continuous cold-flow cryocompression device effectively reduce knee skin temperature to 10–15 °C, where pain and swelling are expected to be attenuated. DesignRandomised controlled crossover trial. SettingUniversity laboratory. Participants32 healthy adult participants recruited (1 dropout) with no contraindications to cryocompressive therapy. InterventionA k-type thermocouple was used to record skin temperature at baseline and every five minutes during a 30-minute cryocompression treatment in a control condition and when using four different device temperature settings (6 °C, 8 °C, 10 °C, and 12 °C) on a continuous cold-flow cryocompression device. Conditions were labelled Control, Con-6, Con-8, Con-10, and Con-12, respectively. Main outcome measuresSkin temperature change (°C) throughout cryocompression; time taken (mins) to achieve skin temperature < 15 °C; and the difference between final skin temperature and device temperature setting (°C). ResultsMedian (IQR) skin temperature after cryocompression was 32.1 °C (29.3–33.4), 12.8 °C (12.1–14.6), 14.3 °C (13.8–15.7), 16.1 °C (15.2–17.3), and 17.7 °C (16.9–18.9) for the Control condition and Con-6, Con-8, Con-10 and Con-12, respectively. It took 20 min (Con-6) and 25 min (Con-8) for skin temperature to reach < 15 °C. A median (IQR) difference of 6.8 °C (6.1–8.6), 6.3 °C (5.8–7.7), 6.1 °C (5.2–7.3), and 5.7 °C (4.9–6.9) for Con-6, Con-8, Con-10, and Con-12, respectively was observed between device temperature setting and final skin temperature. ConclusionsThe device is recommended as it reduced skin temperature to the therapeutic range of 10–15 °C during a 30-minute treatment when using the 6 °C or 8 °C device temperature settings. Future research should determine optimal treatment lengths for cryocompression. Contribution of the Paper•The Physiolab S1 cryocompression device allows users to determine precise temperatures of the ice-water that is circulated around the knee during a treatment.•This paper demonstrates the ability of each temperature setting to reduce skin temperature around the knee to within the target therapeutic range of 10–15 °C.•There is a significant discrepancy between the temperature setting of the device and the skin temperature achieved during a treatment.•Clinicians should not assume that all temperature settings on this and similar devices sufficiently reduce skin temperature of the knee to confer a therapeutic benefit.

Investigating the effect of laser surface melting process parameters on thermal efficiency by reverse analysis and experimental design

In this paper, the effect of the process parameters such as laser power, shielding gas flow and scanning velocity on the actual laser power reaching the surface and thermal efficiency is investigated. For this purpose, the response surface methodology was used to investigate the effect of the process parameters at three levels. In order to measure the data from a 316L stainless steel, four k-type thermocouples are installed in different positions relative to the motion of the laser beam. The actual power was calculated by reverse analysis using the simulated annealing technique and the temperature history was measured by the thermocouples. The thermal model used is an optimized Rosenthal model, which is considered variable with temperature. The results show that for all thermocouples, the highest values of actual power that reached the surface were obtained at laser power of 200[Formula: see text]W, scanning velocity of 2[Formula: see text]mm/s and shielding gas flow of 30[Formula: see text]Lit/min. In addition, by increasing the laser power from 100 to 200[Formula: see text]W, the thermal efficiency decreases by about 4% to 12%. The thermal efficiency also decreases by about 8%, when the scanning velocity increased from 1 to 3[Formula: see text]mm/s. Moreover, the increase of the shielding gas flow from 25 to 35[Formula: see text]Lit/min initially improved the thermal efficiency and then decreased it. The models obtained from the analysis of variance in the heating cycle are in good agreement with the experimental results, but in the cooling cycle, the accuracy of this model decreases.

Thermal Sensing of Photo-Activated Dental Resin Composites Using Infrared Thermography.

The goal of this study was to compare the pulp temperature increase during light curing of different composite thicknesses in deep class I cavities using two thermal sensing tools. Round occlusal class I cavities with a remaining dentin thickness (RDT) of 1 mm from the cavity floor were performed on 15 extracted sound molars. Samples were divided into three groups (n = 5). In group A, cavities were restored using the Filtek Z350 XT conventional composite through the incremental filling technique, whereas group B cavities were restored using the Filtek Bulk-Fill flowable composite through the bulk-fill technique. Specimens of the Filtek Bulk-Fill flowable composite using the incremental filling technique were used to restore cavities in group C. An infrared thermal camera (IRT; Flir, Wilsonville, OR, USA) and K-type thermocouple (Perfect Prime TC0520, New York, NY, USA) were used to measure the heat generated during composite photo-polymerization. There were no significant differences within the same group using either the thermocouple or IRT (p > 0.05). One-way ANOVA showed no significant differences between groups A and C (p > 0.05), whereas group B was significantly different from groups A and C with each sensing tool (p < 0.05). IRT and thermocouple heat readings were comparable. Based on the current findings, the bulk-fill technique resulted in the lowest heat generation among the groups. Therefore, increasing the light-curing time and the number of composite increments was directly correlated with increases in intra-pulpal temperature.

Process Parameter Optimization of Aerospace-Grade Dissimilar Aluminium Alloy 7075 and 2014 by Friction Stir Welding

In friction stir welding process, the selection of optimum process parameter is an important step. To make a welding with high quality in all aspects such as defect free and reduced HAZ region, it becomes necessary to choose the parameter in such a way the temperature developed due to heat generation is in optimum level. A study on the effect of process parameters on temperature distribution and HAZ region is performed for dissimilar combination of AA7075 and AA2014. A statistical model based on Box-Behnken RSM is built to study the interaction effect of parameters on temperature distribution and optimization of process parameter is obtained as is Tool Rotational Speed (TRS) – 1400 rpm, Tool Traverse Speed (TTS) – 1.21mm/s and Tool Size Ratio (TSR) – 4. An experiment of FSW is made with K-type thermocouples for optimized parameter of AA7075+AA2014 and temperature reading is then compared with simulation for validation of model. The prediction accuracy is in the range of maximum 98.69% and minimum 92.45%. It was observed that optimum depth location of thermocouples is beyond the half of thickness because of less error attained as 1.31%.

Assessment of TiO2, Al2O3, and SiO2 nanolubricant with eco-friendly refrigerant as substitute for R134a in a vapour compression system: An experimental approach

The efficiency of R600a, an eco-friendly refrigerant with TiO2, Al2O3, and SiO2 nanolubricants, was investigated and evaluated as a substitute for R134a in a vapour compression refrigerator system. Pressure gauges and K-type thermocouples were used to monitor the temperature and pressure. The power consumption of the refrigerator was observed using the digital wattmeter. Using NIST refprop version 9.0, the refrigerant's enthalpy was determined. The results showed that R600a with nanolubricant TiO2, Al2O3, and SiO2 had lower evaporator temperatures and pull-down times than R134a and pure R600a. For R600a in the based lubricant, TiO2, Al2O3, and SiO2 nanolubricant concentrations in the system, respectively, evaporator temperatures of − 5, − 10, − 7, and − 11 °C were attained after 210, 210, 240, and 240 min of pull-down time. TiO2, Al2O3, and SiO2 nanolubricants increased R600a cooling capacity by 9.7%, 0.5%, and 12.2%, respectively, while lowering power consumption by 23.3%, 17.5%, and 20.2%. R600a/nano mixtures can therefore replace R134a and R600a with pure lubricant in a household refrigerator system.