Many differences exist between the two configurations, whereby the OT design is not only 
easier in concept and design but also has a higher performance ratio, especially in the case of 
large-scale projects.While dosing rates, in ppm, are lower for the OT process, as the coolant seawater has the 
equivalent feed concentration, the large intake flow rate calls for a higher rate of chemical 
dosing than in the case of BR. The net result is higher overall chemical consumption in the 
OT process.The temperature of the intake was around 25-30 oC; therefore, a preheater was added to the 
simulated plant to moderate the intake seawater temperature through the year, whereby the 
influent seawater into the plant was fixed at approximately 40 oC. Some chemicals are added 
to the feed water (anti-scaling, chlorine, and anti-foaming).On the other hand, the elimination of the heat rejection section and the recirculation 
pump, with all of the associated controls and civil work, means lower capital investment and 
simpler operation than is the case with the brine recirculation (BR) configuration.After warming the seawater feed 
in the condenser tubes, part of this feed water is evacuated to the sea (known as cooling 
water),while the rest of the feed water is delivered to the deaerator (known as makeup wateAccording to [22], three major features verify the advancement of the OT 
design--the performance ratio, the top brine temperature and the brine loading, all of which 
are superior.It should be noted here that the main 
disadvantage of the OT design is its high consumption of chemicals for the pretreatment of 
water.The consumption of 
chemicals depends on the volume of seawater to be treated, as well as the concentration ratio.In the BR process, deaeration of the pretreatment is accomplished in a deaerator, 
which is integrated with the last rejection stage.This is a disadvantage since the amounts of noncondensable gases 
released, including oxygen, are much higher than what is released by recycling in The BR 
process [23].Chlorine is added to the seawater 
feed at the source to avoid bio-fouling inside the condenser tubes [24].The top brine temperature can increase106C, which means efficient 
absorption of thermal energy (heat) from heating steam.In any case, 
the selection of a specific configuration depends mainly on economic and operational 
considerations.The BR practice uses very few chemicals for makeup pretreatment.