Study of fouling and corrosion problems related to a solar sea power plant. Progress report, April 1--June 30, 1977

The OTEC heat transfer simulation device, which was developed at CMU in order to investigate heat exchanger biofouling by monitoring heat transfer coefficients, has now been used in several experiments at Keahole Point, Hawaii. The field results have confirmed that the equipment works as expected with a precision in measuring heat transfer coefficients of about 1%. The results show that the biofouling growth is very slow during an initial transient period of about six weeks at which time the fouling resistance is R/sub f/ approximately equal to 20 x 10/sup -5/ hr ft/sup 2/ /sup 0/F/Btu. After this transient, the growth is essentially linear, rising at the rate of about 7 x 10/sup -5/ hr ft/sup 2/ /sup 0/F/Btu-week. These results are independent of material (titanium or aluminum) and flow velocity (6 or 3 feet per second). During the course of these same experiments a preliminary cleaning test was done with a M.A.N. brush. It was found that six passes of the brush reduced the fouling resistance from about 32 hr ft/sup 2/ /sup 0/F/Btu to zero