Open Access

ARTICLE

EFFECT OF TERM OF ERROR ON WET-BULB TEMPERATURE MEASUREMENT USING ASPIRATION PSYCHROMETER

V. W. Bhatkar^a, Anirban Sur^b,*, Anindita Roy^b

a Associate Professor, Marathwada Mitra Mandal’s College of Engineering, Pune-411052, Maharashtra, India
b Associate Professor, Symbiosis Institute of Technology, Symbiosis International (Deemed) University, Pune-41215, Maharashtra, India
* Corresponding authors. Emails: anirban.sur@sitpune.edu.in (AS); vijaybhatkar@mmcoe.edu.in (VWB)

Frontiers in Heat and Mass Transfer 2022, 19, 1-8. https://doi.org/10.5098/hmt.19.3

Abstract

In heating, Wet-bulb temperature in HVAC (heating, ventilation, and air conditioning) applications is crucial for building the equipment. But radiation from the surrounding surfaces caused the errors during the thermodynamic wet-bulb temperature measurement. The wet-bulb temperature of moist air is measured in the current work utilising an aspiration psychrometer designed, developed, and built to reduce the error term caused by radiation and convection heat transfer. Wet-bulb temperature is calculated in the experiments using an aspiration psychrometer at various locations throughout the year, both with and without a shield. It has been found that the error term depends on several factors, including airspeed, the characteristics of wick fabric, the distance a person may breathe between thermometers, and the heat transfer coefficient owing to radiation and convection. A minimum of seven minutes must pass during the measurement of WBT to stabilise heat and mass transfer. It has been noted that the calculated term of error is higher in the afternoon than it is in the morning and evening because of the high solar radiation. The margin of error is approximately 15% in the morning and evening and at its highest in the afternoon. This investigation has led to the conclusion that direct sunlight should be avoided when measuring WBT. It has been discovered that greater heat transfer coefficient values provide the bigger term of error for fabrics with high textile emissivity.

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Keywords

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