Countermeasures to microbiofouling in simulated ocean thermal energy conversion heat exchangers with surface and deep ocean water in Hawaii

Journal Article · Sun Jun 01 04:00:00 EDT 1986 · Appl. Environ. Microbiol.; (United States)

OSTI ID:5472340

Berger, L R; Berger, J A

Countermeasures to biofouling in simulated ocean thermal energy conversion heat exchangers have been studied in single-pass flow systems, using cold deep and warm surface ocean waters off the island of Hawaii. Manual brushing of the loops after free fouling periods removed most of the biofouling material. However, over a 2-year period a tenacious film formed. Daily free passage of sponge rubber balls through the tubing only removed the loose surface biofouling layer and was inadequate as a countermeasure in both titanium and aluminum alloys tubes. Chlorination at 0.05, 0.07, and 0.10 mg liter/sup -1/ for a h day/sup -1/ lowered biofouling rates. Only at 0.10 mg liter/sup -1/ was chlorine adequate over a 1-year period to keep film formation and heat transfer resistance from rising above the maximum tolerated values. Lower chorination regimens led to the buildup of uneven or patchy films which produced increased flow turbulence. The result was lower heat transfer resistance values which did not correlate with the amount of biofouling. Surfaces which were let foul and then treated with intermittent or continuous chlorination at 0.10 mg of chlorine or less per liter were only partially or unevenly cleaned, although heat transfer measurements did not indicate that fact. It took continuous chlorination at 0.25 mg liter/sup -1/ to bring the heat transfer resistance to zero and eliminate the fouling layer. Biofouling in deep cold seawater was much slower than in the warm surface waters. Tubing in one stainless-steel loop had a barely detecting layer after 1 year in flow. With aluminum alloys sufficient corrosion and biofouling material accumulated to require that some fouling countermeasure be used in long-term operation of an ocean thermal energy conversion plant.

• Research Organization: Univ. of Hawaii at Monoa, Honolulu
• OSTI ID: 5472340
• Journal Information: Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 51:6; ISSN AEMID
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140800* -- Solar Energy-- Ocean Energy Systems
560302 -- Chemicals Metabolism & Toxicology-- Microorganisms-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL FOULING
CHEMICAL REACTIONS
CHLORINATION
CLEANING
CONTROL
CONVERSION
ENERGY CONVERSION
ENERGY TRANSFER
FEDERAL REGION IX
FOULING
HALOGENATION
HAWAII
HEAT EXCHANGERS
HEAT TRANSFER
NORTH AMERICA
OCEAN THERMAL ENERGY CONVERSION
SEAS
SIMULATION
SOLAR ENERGY CONVERSION
SURFACE WATERS
TEMPERATURE DEPENDENCE
USA