The fiber optic refrigeration cycle monitor
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 Until recently, this measurement has been limited to the analysis of samples withdrawn from the absorption machine after system shut-down.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.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6653784
- Report Number(s):
- CONF-870584-1; ON: DE87006632
- Resource Relation:
- Conference: SPIE technical symposium on optics and optoelectronics, Orlando, FL, USA, 15 May 1987; Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
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