Ultrasonic Air Temperature Sensing for Automatic Climate Control - Sensor Development

Han, Taeyoung; Lambert, David K.; Oberdier, Larry M.; Partin, D. L.; Sultan, Michel F.

doi:10.4271/2003-01-0740

Cited by 4 publications

(1 citation statement)

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“…Perceived thermal comfort is better correlated with breath-level temperature than it is with the output of the conventional in-car sensor. To sense bulk air temperature, a method was proposed transparent to the occupant-to send a pulse of ultrasound through the air [3,4,11].…”

Section: Introductionmentioning

confidence: 99%

An ultrasonic air temperature measurement system with self-correction function for humidity

Tsai

Chen

Liao

2005

Meas. Sci. Technol.

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This paper proposes an ultrasonic measurement system for air temperature with high accuracy and instant response. It can measure the average temperature of the environmental air by detecting the changes of the speed of the ultrasound in the air. The changes of speed of sound are computed from combining variations of time-of-flight (TOF) from a binary frequency shift-keyed (BFSK) ultrasonic signal and phase shift from continuous waves [11]. In addition, another proposed technique for the ultrasonic air temperature measurement is the self-correction functionality within a highly humid environment. It utilizes a relative humidity/water vapour sensor and applies the theory of how sound speed changes in a humid environment. The proposed new ultrasonic air temperature measurement has the capability of self-correction for the environment variable of humidity. Especially under the operational environment with high fluctuations of various humidity levels, the proposed system can accurately self-correct the errors on the conventional ultrasonic thermometer caused by the changing density of the vapours in the air. Including the high humidity effect, a proof-of-concept experiment demonstrates that in dry air (relative humidity, RH = 10%) without humidity correction, it is accurate to ±0.4 °C from 0 °C to 80 °C, while in highly humid air (relative humidity, RH = 90%) with self-correction functionality, it is accurate to ±0.3 °C from 0 °C to 80 °C with 0.05% resolution and temperature changes are instantly reflected within 100 ms.

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Section: Introductionmentioning

confidence: 99%