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Proceedings Paper

The Fiber Optic Refrigeration Cycle Monitor
Author(s): L. N. Klatt; D. T. Bostick; H. Perez-Blanco
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Paper Abstract

The measurement of absorbent concentration is a key control parameter in operating and assessing the performance of absorption heat pump systems. Because most refrigerant absorbent fluids are binary mixtures, the measurement of refractive index has been used routinely to directly determine the concentration of absorbent fluid components. Until recently, this measurement has been limited to the analysis of samples withdrawn from the absorption machine after system shut-down. The Fiber Optic Refrigeration Cycle Monitor (FORCM) is the first device capable of making multiple and in-situ, real-time measurements of refractive index at user-definable points within operating absorption machines. The refractive index of the solution is determined by measuring light loss from an unclad segment of an optical fiber that is immersed in the absorption fluid. Changes in fluid refractive index alter the angle at which the light rays are totally internally reflected at the core-fluid interface, thereby altering the light transmission efficiency of the fiber. The unclad portion of the fiber is placed at a point within the absorption vessel for which the fluid composition measurement is desired. Any number of modified optical fibers can be installed within a system. A thermocouple junction adjacent to each fiber measures the local fluid temperature. The combination of local concentration and temperature measurements allows in-line monitoring and control of the system, as well as provides a detailed study of heat and mass transfer processes occurring within these machines. The operating characteristics of the FORCM are described in this paper.

Paper Details

Date Published: 6 October 1987
PDF: 6 pages
Proc. SPIE 0787, Optical Techniques for Sensing and Measurement in Hostile Environments, (6 October 1987); doi: 10.1117/12.940676
Show Author Affiliations
L. N. Klatt, Oak Ridge National Laboratory (United States)
D. T. Bostick, Oak Ridge National Laboratory (United States)
H. Perez-Blanco, Oak Ridge National Laboratory (United States)


Published in SPIE Proceedings Vol. 0787:
Optical Techniques for Sensing and Measurement in Hostile Environments
Calvin H. Gillespie; Roger A. Greenwell, Editor(s)

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