Assessment of black globe thermometers employing various sensors and alternative materials

Vega, Felipe Andrés Obando; Ríos, Ana Paola Montoya; Saráz, Jairo Alexander Osorio; Quiroz, Luis G.; Damasceno, Flávio Alves

doi:10.1016/j.agrformet.2019.107891

Cited by 16 publications

(6 citation statements)

References 16 publications

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“…The results of this measurement were very satisfying because the error that occurred was very small. This was also in line with previous research that reported that the accuracy of the DS18b20 was ± 0.5°C (Obando Vega et al 2020). Thus, this sensor was very good to be applied to an ohmic heating apparatus as a data acquisition system for measuring the temperature of the product during ohmic heating.…”

Section: Resultssupporting

confidence: 93%

Fabrication and performance test of a multipurpose ohmic heating apparatus with a real-time data logging system based on low-cost sensors

Sagita,

Hidayat,

Darmajana

et al. 2024

Res. Agric. Eng.

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Ohmic heating is an emerging technology currently in high demand for application in various processes. In this research, a prototype of a multipurpose ohmic heating apparatus was successfully designed, fabricated, and tested. This apparatus was designed based on low-cost and versatile sensors and components available worldwide. Three independent chambers could be operated parallelly and individually with different treatments. Parameter data, i.e., voltage, electrical current, the temperature of heated material and environmental humidity-temperature, could be recorded by an embedded data logging system. The sensor had been tested and validated by comparing all the sensors used with commercial standard instruments. The result showed that all sensors had high measurement accuracy, indicated by very low mean absolute error (MAE) and mean absolute percentage error (MAPE), with R 2 > 0.999. The performance test revealed that product temperature could be accurately maintained according to the set point temperature with a deviation value lower than 0.1 °C. The data logging system was able to record and store the parameter data in SD card memory for up to several days without interruption. The prototype of the ohmic heating apparatus could be an effective alternative to process many purposes such as pasteurisation, cooking, warming, and fermentation based on the ohmic heating principle.

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Section: Resultssupporting

confidence: 93%

Fabrication and performance test of a multipurpose ohmic heating apparatus with a real-time data logging system based on low-cost sensors

Sagita,

Hidayat,

Darmajana

et al. 2024

Res. Agric. Eng.

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“…Air temperature was measured by DS18B20 temperature sensors [59]. Both these sensors are commonly used in different scientific research [60][61][62] mainly because of the easy connection of many measuring points into one bus, good accuracy and low cost [63]. The same sensors were also used to measure floor temperature.…”

Section: Measurementsmentioning

confidence: 99%

Selected Aspects of Indoor Climate in a Passive Office Building with a Thermally Activated Building System: A Case Study from Poland

Michalak

2021

Energies

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Modern buildings with new heating, ventilation and air conditioning (HVAC) systems offer possibility to fit parameters of the indoor environment to the occupants’ requirements. The present paper describes the results of measurements performed in an office room in the first Polish passive commercial office building during four months of normal operation. They were used to calculate parameters describing thermal comfort: vertical air temperature profile, floor surface temperature, predicted mean vote (PMV) and predicted percent of dissatisfied (PPD). Obtained results confirmed good thermal conditions in the analysed room. The average temperature of the floor’s surface varied from 20.6 °C to 26.2 °C. The average vertical air temperature, calculated for working days, was from 22.5 °C to 23.1 °C. The temperature difference between the floor and 5 cm below the ceiling was from −0.9 °C to 6.3 °C. The PMV index varied from 0.52 to 1.50 indicating ‘slightly warm’ sensation, in spite of ‘neutral’ reported by employees. Also measured cooling and heating energy consumption was presented. The performed measurements confirmed the ability of thermally activated building system (TABS) to keep good thermal conditions.

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“…As stressed in two recent investigations [25,28], over the past years many studies have been carried out on the mean radiant temperature and globe thermometers [25,29,30]. The most debated issues were the effect of materials on the accuracy [31][32][33][34][35][36], its response time which seems to be acceptable for continuous monitoring only for table tennis balls [20,25,28,32,[36][37][38], and, finally, the correction factors of small globes in case of WBGT measurements [28,[39][40][41][42]. On the contrary, few investigations have been focused on the metrological characterization of globes and their accuracy in the measurement of the mean radiant temperature [25,[43][44][45][46].…”

Section: Introductionmentioning

confidence: 99%

Mean Radiant Temperature Measurements through Small Black Globes under Forced Convection Conditions

et al. 2021

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One of the most critical variables in the field of thermal comfort measurements is the mean radiant temperature which is typically measured with a standard 150 mm black globe thermometer. This is also the reference instrument required for the assessment of heat stress conditions by means of the well-known Wet Bulb Globe Temperature index (WBGT). However, one of the limitations of this method is represented by the relatively long response time. This is why in recent years there has been a more and more pressing need of smart sensors for controlling Heating Ventilation and Air Conditioning (HVAC) systems, and for pocket heat stress meters (e.g., WBGT meters provided with table tennis balls). Although it is widely agreed that there is a clear advantage of small probes in terms of response times, their accuracy is a still a debated matter and no systematic studies aimed at metrologically characterizing their performances are actually available, due to the difficulty of reproducing measuring conditions such as a black enclosure at uniform temperature. In this paper the results of a metrological analysis of two small globes (38 and 50 mm diameter) carried out by means of an experimental apparatus specifically designed to reproduce a black uniform enclosure are presented and discussed. Experimental results revealed a systematic underestimation of the mean radiant temperature predicted by small globes of more than 10 °C in forced convection and at high radiative loads.

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Assessment of black globe thermometers employing various sensors and alternative materials

Cited by 16 publications

References 16 publications

Fabrication and performance test of a multipurpose ohmic heating apparatus with a real-time data logging system based on low-cost sensors

Fabrication and performance test of a multipurpose ohmic heating apparatus with a real-time data logging system based on low-cost sensors

Selected Aspects of Indoor Climate in a Passive Office Building with a Thermally Activated Building System: A Case Study from Poland

Mean Radiant Temperature Measurements through Small Black Globes under Forced Convection Conditions

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