CHARACTERIZATION OF METROLOGI LIPI’S PSYCHROMETER

Purwowibowo, Arfan Sindhu Tistomo, Rachman Soleh

Abstract

This paper describes characterization of the first psychrometer developed by Puslit Metrologi LIPI. The psychrometer is dedicated to operate at a temperature range of 25 °C to 65 °C and 15 %rh to 90 %rh. The highest temperature range is limited by the local traceability for dew point measurement. The work includes the determination of psychrometer coefficient and its characteristics due to effect of the wind velocity which is adjusted by applying voltage 12 V and 5 V to the fan.<BR />When 12 volt of voltage is applied, the psychrometer coefficient obtained by using Apjohn and Ferrel equations yields 8.3 &times; 10^-4 °C^-1 and 7.2 &times; 10^-4 (1 + 0.0043 <i>t</i>_w) °C^-1, respectively. The first value produces relative humidity deviation (standard error estimate) from the experimental data less than 2.8 %rh while the second is less than 1.2 %rh. When 5 volt of voltage is applied, both the psychrometer coefficient and the deviation become larger, and on relative humidity of 90%rh the psychrometer coefficient obtained from the experimental data drops considerably which means that wind velocity is insufficient to operate the psychrometer.

Keywords

psychrometer, wet bulb, hygrometer, humidity, calibration

Download

IMEKO-WC-2015-TC7-204.pdf

DOI

-

IMEKO TC

TC7 - Measurement Science

Back to the proceedings