There are five typical systems for cooling a vessel four with the compressor in a remote location:
Commonly found on larger yachts and ships, consisting of the chiller unit itself which is typically placed in the engine room or bilge area, and fan coils throughout the boat.
The chiller makes cold water that is constantly circulated in a closed loop throughout the numerous fan coils of the vessel. A plumbing system consisting of an expansion tank, storage tank, circulating pump and insulated piping are required for the cooled water loop, and an additional pump and plumbing system for the raw water cooling is required.
When a cabin requires cooling, the fan engages on
that particular fan coil, thus cooling the air in that
cabin. Several chiller units may be plumbed in
parallel so that differing numbers of units may be
running at any given time to maintain a predetermined
water temperature as dictated by the heat load on the
system. This also results in redundancy
eliminating any down time.
These systems are the quietest and take up the least amount of room in the cabin.
The most typical installation of the recent past - the condensing unit is in the bilge and insulated refrigerant lines connect the condensing unit to the evaporator(s) in the cabin(s).
The biggest disadvantage of this in today's market is the time and expense of having a licensed HVAC professional evacuate and charge the system with refrigerant when installed, and the necessity for the same HVAC licensed professional to evacuate and recover the refrigerant if a repair is required.
These systems always seem to have leaking problems, and the condensing unit in the bilge has a greatly reduced service life being in the wet marine environment of the bilge.
Mini Split Systems:
This fairly new innovation has one variable speed condensing unit supplying refrigerant to up to eight small remote evaporators. This can result in a very significant savings to the end user in certain situations, such as a home, by cooling only the rooms that are occupied.
In a marine application it's not typical for air conditioned areas to not be occupied, so these savings are not realized in the marine industry. However, the many detriments of these systems remain and they can be acute in a marine application. It's no wonder why no marine HVAC manufacturer makes mini split systems. If you do decide to install a residential system on your vessel, you should expect to be replacing the outdoor components quite frequently! Due to the adverse marine environment you might get a couple years out of the condensing unit!
In operation when one of the remote evaporators calls for cooling, the slave board in the remote evaporator sends a signal to the mother board in the condensing unit. This triggers the compressor to ramp up and open the solenoid going to that evaporator to provide refrigerant thus cooling the room.
Every remote evaporator requires its own refrigerant lines connecting it to the condenser. On a typical vessel you will have hundreds of feet of refrigerant lines, half of which are cold return lines that must be insulated. Each evaporator requires separate piping and wiring of the power cable, the refrigerant tubing, the suction tubing, and a condensate drain between itself and the condensing unit. Now imagine all of this buried behind panels, deck heads and cabinetry. This is reminiscent of the split systems of the past which have fallen out of favor in the marine industry over the years because of the ongoing maintenance and down time due to relentless refrigerant leaks caused by rotted copper lines and leaking brazed joints that are so hard to locate.
Imagine the difficulty a technician will have trying to sniff out a leak that could be anywhere along these hundreds of feet of refrigerant lines. At least every 50' (the length of a roll of copper tubing) you have a brazed joint, and these lines are buried in the structure of the moving/flexing vessel. With a SINGLE leak the ENTIRE system is down!
As proven time and time again there is "no free lunch" with thermodynamics, so the tonnage is the same resulting in no weight or current savings. The only way to save weight is to use thin sheet metal and other inferior components. If the load is 12 tons you will need twelve tons of cooling regardless of the type of system - you will NOT be running a mini split system at 25% capacity at high noon with a hundred people on board! It will be 100%! A chiller system works the same way so at 10PM your Flagship Marine chiller might be running ten minutes/hour, so the total current consumption will be basically the same with any system.
The condensate is oftentimes problematic because it can be difficult finding a sensible means of running a condensate drain from every remote wet evaporator. Sometimes it's easier to run dry ducting rather than install wet evaporators.
conclusion, we believe a chiller system in these
applications is much more desirable, and especially
with Flagship Marine equipment you will have ZERO
expensive/proprietary printed boards that can cost
you a small fortune over the years. Mini
splits are the MOST complicated/complex systems
electronically. Printed circuit boards and naked
copper tubing don't do well on a moving, flexing
vessel in a marine environment!
Self Contained Systems: Because of the remarkably quiet rotary and scroll compressors, the never ending refrigerant regulations, the dramatic size reductions of these units and the cost savings of the equipment and installation, the self contained systems have become very popular.
The complete units are only a few inches larger that the evaporators of the split systems and the fan coils of the chiller systems.
The typical self contained unit needs only a 5/8" non-insulated raw water supply for cooling the condenser - you will not need any insulated water lines or insulated refrigerant lines and you will never need a licensed HVAC technician to install or remove these units.
Because EVERYTHING is inside the air conditioned environment of the vessel, the component's service life is extended - nothing is exposed to the marine environment other than the raw water pump.
With multiple units on a vessel, if one unit should
happen to fail, only that area is without air
conditioning, and very little skill is needed to
remove the unit for service.
The primary disadvantage is that you will need to pump sea water to each self contained unit and any leak would present a corrosion and sinking hazard. To remedy this you may wish to consider having fresh water cooled self-contained units using a Fernstrum™ keel cooler or a Sen-Dure® heat exchanger - check out http://www.flagshipmarine.com/heat exchanger.html
Units from 6,500 BTUs to 180,000 BTUs are available,
so whether you are air conditioning an 18 foot cuddy
cabin or a several hundred foot ship you may reap the
many benefits of individual self contained units.
Systems: Primarily for large vessels
and ships - a powerful blower motor pressurizes the
cooled/heated air and distributes this air throughout
the vessel frequently through PVC piping that can be
quite small in diameter because of the high pressure.
This eliminates having the HVAC equipment in the
living quarters of the vessel and eliminates the need
for condensate and electric lines throughout the
vessel. Noise from the high speed blowers are
the biggest disadvantage of these systems.
Flagship Marine, Inc., 2427 SE Dixie Hwy., Stuart, Florida 34996 - USA
Phone: 772-283-1609 Fax: 772-283-4611 Wats: 800-316-6426 firstname.lastname@example.org
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