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International Journal of Thermophysics

, Volume 29, Issue 5, pp 1578–1588 | Cite as

The New KRISS Low Frost-Point Humidity Generator

  • B.I. Choi
  • H.S. Nham
  • S.B. Woo
  • J.C. Kim
  • S.Y. Kwon
Article

Abstract

A new low frost-point humidity generator (LFPG) has been designed, and its performance has been tested, in order to extend the calibration capabilities to the low frost-point range at KRISS. The water vapor–gas mixture is generated by saturating air with water vapor over a surface of an ice-coated saturator under the conditions of constant temperature and pressure. This LFPG covers a range of frost point from  − 99 °C to  − 40 °C. The temperature of the saturator, which is controlled by thermoelectric devices and a two-stage mechanical refrigeration system, is stable within 5 mK, and the difference between the saturator temperature and the frost point generated at the saturator outlet is less than 20 mK. This stability is achieved by using oxygen-free high-conductivity copper materials as the saturator body, and applying a precision PID temperature control system. The performance of this new LFPG system is compared with the KRISS standard two-temperature generator in the frost-point range ( − 80 to  − 40) °C, and its performance is tested with a quartz crystal microbalance (QCM), which was built at KRISS, to  − 91 °C.

Keywords

Dew point Frost point Humidity standard Low frost-point generator Quartz crystal microbalance Thermoelectric device 

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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • B.I. Choi
    • 1
  • H.S. Nham
    • 1
  • S.B. Woo
    • 1
  • J.C. Kim
    • 1
  • S.Y. Kwon
    • 1
  1. 1.Division of Physical MetrologyKorea Research Institute of Standards and Science, 1 Doryong-Dong Yuseong-GuDaejeonKorea

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