Sea Water for HVAC Cooling? 3

[cguerra757]

Has anybody designed a sea water cooling system for HVAC use? I'm working on a project with year round cooling demand (150 tons) and very high electricity cost. Beacuse of proximitey, I'm entertaining the idea of using sea water for heat rejection. My initial questions are how to arrange the inlet pipe. What material must be used for the pipeline? Would HDPE work or do I need exotics, CuNi / Stainless? Should I go off shore to very deep 40-50F water (more $) or keep the pipe close to shore and use the 60-80F water(less $?) to run a chiller at very low kW/TON? Can I avoid major marine construction/mobilization if I keep the intlet & oulet near shore? What protection do I need to provide for the inlet and outlet pipes? Any thoughts are appreciated.

 

[EnergyProfessional]

I think if you consider that first talk to EPA/DNR and whoever else has autority over that part of the coast. You can't just run pi;es into the ocan over the beach.

the idea sounds pretty good, if you jsut had the 40-50°F water you only needed an HX... so I think it is not that easy or veryone woudl do it.

I'f think maintaining the inlet will be some work so the marine life doesn't use it as a cave to live in etc.

 

[317069]

can you provide more details about your application.

 

[GMcD]

I've done it before, but as HerrKaLuen has pointed out there are a lot of things to deal with first - deal with local environmental officials to get permission, as well as required maximum water discharge temperatures permitted where your discharge is located, then the water quality and filtration requirements need to be verified - if you have a deeply shelving shore to get below the low tide region without running too far with your intake pipe, then a filter/sump with traveling screens will be required to keep the local flora and fauna from clogging the intake in short order. Pipe materials can be HDPE or PVC and you'll need a bit of hypochlorite injection to keep things from growing inside your pipe system and heat exchanger. A shell and tube HEX is probably the best choice for easier cleaning, and it'll have to be admiralty brass or titanium to withstand the seawater.

My past applications have been both seawater as well as freshwater lake applications and we ran the seawater through the condenser bundles of the chillers and then dumped the seawater back out some distance away from the tidal zone. Seawater is commonly used in ship and submarine cooling applications, so research Naval design material.

 

[RonShap]

http://www.google.com/about/datacenters/inside/locations/hamina/index.html

It was done recently for this data cetner

 

[ProcessHVAC]

I've done groundwater and lake water, but never seawater. Approvals and design for operational issues are tricky but other than that, it is possible.

 

[IRstuff]

The primary issue, once you get past the regulatory and other hurdles is whether the increased maintenance is going to offset whatever cost savings there might be from the electricity bill.

> corrosion
> fouling
> protection from damage, both land and seaborne vehicles, people, and animals
> efficiency losses due to meeting regulatory requirements
> additional maintenance personnel

TTFN
faq731-376

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[Drazen]

If you don't know what kind of debris regularly arrives at shore, you will have trouble in designing water inlet.

Regular cleaning anyhow should be part of cost planning and included in design specs. Yes, it means divers who make cleaning every one-two-three or whatever needed number of months.

 

[MikeHalloran]

A while back, I was asked to design a facility for testing marine Diesel engines. It happened that the available space was next to an industrial canal.

Nobody had a problem with us drawing cooling water from the canal, but everybody, including the Corps of Engineers and the EPA and every local AHJ, had a huge problem with us discharging the very same water, just a few degrees warmer, back into the same canal.

Said facility has not yet materialized, and probably won't.




Mike Halloran
Pembroke Pines, FL, USA

 

[dynamo78]

As GMCD Said. You needed to survey the area for what debris or sea creatures are abound in the area. was involved in the design of a seawater screen, the issue was the intake header sometimes are clogged with jelly fish so the condenser suffers and consequently the power plant. Its workable but consider the investment of a travelling screen or conveying system to divert any debris.
HTH

 

[cry22]

I think you are asking the wrong question and your problem is not stated correctly.
the only problem seems to be cost of electricity. what is the cost of other fuels in your area? fuel oil? natural gas? propane? water? you can use any of these fuels for electricity. WHAT IS YOUR CLIMATE?

you could have a dedicated generator as a prime power using oil or natural gas. This may prove less expensive than running your system into the sea.

If you are in a somewhat dry climate, you could eliminate the chiller and use evaporative cooling - such as Indirect/Direct type and it should reduce your energy substantially, to a point where your problem goes away altogether.

Just saying.

 

[VEEKRISH]

Look at using cupro-nickel condensers (shell and tube).
Piping could be HDPE.
Go below the low tide line.
Look at local environmental laws and codes.
Filtration.
These are some of the key issues.
Need to probably look at de-scaling more frequently