sea-water cooled condensator piping dimensions

[antonio nunes]

Hello to you all.
As a newly educated marine engineer, i´m working on bord a passager vessel(capacity: 1500 PAX + 230 crew members) where one of my areas of responsability is refrigeration.

My first serious task is to set up a new quick freezer unit. The cooling load estimated is 5 kW.
My actual issue is wich parameters am I to use on an accurate dimensioning the piping diameter on sea water inlet and outlet to condenser.
I would appreciate any feedback/experience you might have on this matter.

Moreover, I want to thanks all the people who formerly assisted me upon my graduation final project.

Best regards Ant

[Tesla]

Hi Ants and welcome to our forum,

I think you will be using something like cupranickel tubes for corrosion and need to allow for fowling which is greater than normal systems. It's been a long time since I worked on marine cooling systems. One of my old bosses is a guru and is a member of this forum you could search and possibly PM him Graem Blackman. I understand he runs a company called Inter-Marine.

[antonio nunes]

Hi Tesla..thanks 4 the tip.I´ll se if it´s possible to draw some of his attention on the matter-----sure, I´ve got enough Cu Ni Fe pipe to do the job..the question is the dimensions ( Ø 44,5 x 1,50)...I think that will be overkill since the condenser has volume of 0,7 liter cooling medium(sea water)-------i imagine that thermo regulating valve will b forced to nearly close totally......dun know--gotta sort this issue out. Once agian thanks. B well

[TXiceman]

You need to size your piping according to normal pipe losses for the flow required for the condenser. So you need to know how much water flow is required and the pressure drop through the condenser. Then based on the sea water pump pressure and the maximum pressure loss you are allowed, size the pipe acordingly. You also need to keep in mind, acceptable pipe velocities fro the service.

In other words there is no cook book answer that will be guaranteed correct.

Ken

[antonio nunes]

Thanks Ken..I appreciatted. That´s was exactly the type of info I was aiming to get.
Gonna starting working on it.
I´ll most probably get back to the forum on the issue of regulating seawater masseflow towards intented condenser pressure...again, gotta work with the spares we´ve got on stock--
Cheers------------Merry Christmas and all the best--------------*it goes for everybody

[MikeHolm]

Whenever we do any kind of heat transfer through a BPHE and salt water, we use a titanium stainless HX. It is the only way i know of to have any longevity.

[antonio nunes]

;-)..I´m afraid if I suggest the chief-engineer that material, he´ll chop my head off---we run on a slim budget,u know, specially on the refrigeration area. But thanks for the input.