The Status of Research § Development for Improving 



the Long-Term Performance of Air-Cooled 



Condensers in Marine Environments 



I. DIMENSIONS OF THE CORROSION/FOULING PROBLEM 



The Department of Defense Construction Criteria Manual (reference 1, 

 chapter 8. pp 8-15) makes mandatory the outdoor installation of air- 

 cooled condensers, evaporative condensers and cooling towers.. But it also 

 acknowledges that some problems may result by its statement: 



"In order to avoid corrosion problems, no air conditioning equipment, 

 including rooftop units, shall be installed on the roof of a 

 building within two miles of the ocean. When such equipment is 

 installed on the ground, it should be located on the leeward side 

 of the building. Special consideration of corrosion problems 

 shall be made for any air conditioning (including heating and 

 ventilating) equipment which is to be installed within ten miles 

 of the ocean." 



Nevertheless, the majority of Navy air conditioning and refrigeration/ 

 equipment cooling installations employing air-cooled condensers appear, 

 of necessity, to have been installed closer to the ocean than the two 

 and ten-mile DoD limits would normally permit. Although operating and 

 maintenance costs may be higher than at interior locations, little design 

 consideration is given to such special conditions. The reason is 

 mechanical cooling equipment has become standardized to such an extent 

 that custom designs are discouraged. Clearly, standardization has 

 reduced the cost of an initial installation. What is not so clear is 

 whether this gain has been accomplished in exchange for an even greater 

 loss due to the resulting increase in operating expense and replacements. 



The Design Problem of Fouling 



A design engineer will normally match the capacity of a compressor 

 and a condenser to load requirements, following reference 1, which states: 



"In the selection of air-cooled condensers, careful engineering 

 consideration shall be given in the determination of the capacity 

 of the condenser and the condenser fan (or fans) in relation to 

 the compressor size. Often the selection of a larger capacity 

 condenser will permit use of a smaller compressor motor so that 

 total electrical input to both condenser and compressor is reduced. 

 In other cases where the compressor motor size cannot be reduced, 

 the electrical consumption of a given size compressor can be 

 reduced by using a larger capacity condenser and, therefore, the 

 combined electrical input to both components can be reduced. 

 Capacities of air-cooled condensers shall be selected to provide 

 optimum operating costs over the life of the equipment, consistent 

 with initial equipment costs. Full consideration shall be given 

 to the use of air-cooled condensers for all reciprocating refrigera- 

 tion compressors unless there are compelling technical or economic 

 reasons for using water cooling." 



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