RP-895 -- Improving Thermal and Flow Properties of Chilled Water PDF

The flow loop facility used for 801-RP was modified by using ethylene glycol in the chiller and connecting it to the chilled water loop through a heat exchanger in which the glycol flows in the shell and the chilled water in the tubes. Tests were run with the addition to the chilled water of 25 percent by weight of a 90/10 hexadecane/tetradecane mixture (PCM) and 10 percent (by weight of the PCM) of a liquid surfactant (Wisk). Chiller operation was steady, and between 60 percent and 80 percent of the PCM consistently froze in the "cold" heat exchanger and melted in the "hot" heat exchanger. Improvements in volumetric thermal capacity by the addition of that PCM mixture to chilled water varied from 12 percent to more than 20 percent for a chiller temperature range varying from 15 F (8.3°C) to 10 F (5.6°C). The upper, limits of the PCM addition to chilled water should be determined and field tests of such a mixture should be undertaken.