Spatially resolved optical measurements of water partial pressure and temperature in a PEM fuel cell under dynamic operating conditions

S. Basu, M. W. Renfro, B. M. Cetegen

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


In situ non-intrusive measurements of water vapor partial pressure and temperature were performed simultaneously along two gas channels on the cathode side of a PEM fuel cell using tunable diode laser absorption spectroscopy. This measurement technique developed by us was utilized earlier to make measurements in a single bipolar plate channel of a prototype PEM fuel cell. The current study examines the variation of water partial pressure and temperature near the flow inlet and outlet during operation under both steady state and time-varying load conditions. For steady-state operation, an increase in the water vapor partial pressure was observed with increasing current density due to electrochemical production of water. As expected, the measurement channel near the inlet of the flow path showed a lower water vapor partial pressure than the outlet under identical load conditions; however, the quantitative distribution of water content across the cell is important to understanding operational behavior of a PEM fuel cell. These quantitative water concentration differences between two measurement channels are reported with variations in cell load and temperature. Temperature in the gas phase remained constant due to thermal equilibrium of the fuel cell. For time varying operation, no phase lag was observed between the load and the water vapor partial pressure. The outlet measurement channel showed higher partial pressure than the inlet with larger differences for increasing cell load. The transient data matched the steady-state measurements at the same conditions. A temperature rise from the controlled value was observed at high current densities for the unsteady operation; thus, the temperature did not equilibrate on the same time scale as the water partial pressure.

Original languageEnglish
Pages (from-to)286-293
Number of pages8
JournalJournal of Power Sources
Issue number1
StatePublished - Nov 8 2006

Bibliographical note

Funding Information:
The research reported here was funded by the U.S. Army RDECOM, CERDEC (Fort Belvoir, VA) through the Connecticut Global Fuel Cell Center (CGFCC).


  • Laser absorption
  • Optical diagnostics
  • PEM fuel cell testing
  • Temperature
  • Water vapor concentration

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering


Dive into the research topics of 'Spatially resolved optical measurements of water partial pressure and temperature in a PEM fuel cell under dynamic operating conditions'. Together they form a unique fingerprint.

Cite this