Ductless AC systems

Would be interested to see some actual specifications at various temps rather than general speculation. All I know is from rough extrapolating comparing the two in the same climate and the same air temps, I haven't been strongly impressed. There may well be a difference, but it just hasn't jumped out at me.

BTW, I noted the extra maintenance factor for the marine system, our boat being in a very high growth area ( I even had a diver come every month in the winter) when I was making my comparisons.

Would be interested to see some actual specifications at various temps rather than general speculation.

>Very high efficiency up to 24SEER is possible with the compact mini split system<

Most folks just use the gov SEER rating for their comparisons.

The gov is usually wrong , but for comparison A vs B they should give you the idea.

Any idea what the SEER of an ancient boat system was claimed when new?

FF said:

Would be interested to see some actual specifications at various temps rather than general speculation.

>Very high efficiency up to 24SEER is possible with the compact mini split system<

Most folks just use the gov SEER rating for their comparisons.

The gov is usually wrong , but for comparison A vs B they should give you the idea.

Any idea what the SEER of an ancient boat system was claimed when new?

Click to expand...

I doubt they gave a seer rating as there isn't ( to my knowledge ) any govt. energy standards for boats... especially older systems.

This one specs a SEER up to 27.2 on a Fujitsu mini system..

Wall Mounted 9 - 15,000 BTU Hi SEER - Fujitsu Ductless Mini-Splits

HOLLYWOOD

The problem with that Fujitsu is it is 240V , which is not common at every dock, and most small boats use 120v setups .

There are 120V units and as time goes on there will probably be more 120V units built , but so far no marine or RV air cond folks are willing to scrap the current antique system and embrace the future.

This is no doubt caused by the lack of OTS parts a system can be assembled from.

So far all the efficient setups are complete Systems .
Simply repainting systems (like Westerbeak or Ford Econo Power ) might not work.

The big boat folks ( Meters , not feet) that have to pay for electric at a slip will probably be the first to use the Mini Splits for new builds..

Eventually the smaller boats will have a recess or two where the units can be mounted outside .

No more midnight shutdowns to clean jelly fish out of the seawater cooling setup!!!

No mote expen$ive toaster heat (electric heat element ) when its cool !

FF said:

The big boat folks ( Meters , not feet) that have to pay for electric at a slip will probably be the first to use the Mini Splits for new builds..
!

Click to expand...

Well, I've got meters, maybe only 11 of 'em, but I've got 'em.

I am definitely interested in doing something radical with my Marine A/C system. Seeing the installation on the Hong Kong Manatee is good enough for me, but as Cal pointed out, establishing the cost/efficiency factor to swing one in favor of a Mini-Split over a marine system is just not clear. I may try it anyway but I'd sure prefer a 120V from a good Mfg..

I am hoping the marine AC units will catch up with today's standards in residential HVAC

The new mini splits are amazing the efficiency in heat transfer is amazing we have a 2013 mitsubishi that I think is a 24 seer

now if there was a way to take that unit and pass water through for the cooling in theory you would increase the heat transfer by over 20 times ( my memory form engineering school was water is 20-30 times more efficient then air at transfering heat)

that being said I would stay away from non Marine HVAC units on a boat unless you had a house boat

Comparing a new, high efficiency unit intended for residential and commercial use to an older marine unit doesn't really accomplish anything. It's apples to cucumbers.

For many of use, obtaining the highest possible efficiency at the expense of appearance, space efficiency and longevity just doesn't make sense unless you are powering the unit with your genset or inverter or if you're paying for metered shore power. Many of us pay a fixed rate for electric power.

Why couldn't one make a Hybrid with heat exchange from keel cooling or coils submerged in Sea Chest. True, thin coil material wouldn't last long in salt by itself, but with a sacrificial metal bonded, maybe.

It should be noted that while most marine refrigerators use air to air heat transfer (and warm the galley in the process), more efficient units are available that work much like the typical marine air conditioner, transferring the heat to sea water.

Same principal, moving heat from one place to another.

>It should be noted that while most marine refrigerators use air to air heat transfer (and warm the galley in the process), more efficient units are available that work much like the typical marine air conditioner, transferring the heat to sea water.<

The sailors are the most concerned with efficient refrigeration , as many have only solar or the main engine to produce electric.

Most sailors do not replace a sea water fridge machine ,with another, as the complexity and electric cost of a pump make up for any claimed gains.

The hassle of no refrigeration while hauled out is a big looser for sea water cooling too.

The reefer run times are mainly set by the size of the box and the heat transfer ability of the box contents.

The new mini splits are more efficient at cooling , and a snap to install compared to water cooled marine stuff , BUT the huge advantage is HEAT , where many will put out 5X as many BTU as a toaster heat element for the same amps cost.

For a live aboard this could be a real difference , my last slip was $.25c a KW , with oil heat , I didnt care , but many new-bees try electric thinking its cheap, till they get the first months bill.

For what it's worth, I checked the power consumption label on a 24,000 btu "inverter" mini-split system we have (just the outside unit). 1.9kw cooling. Then checked a Webasto all-in one unit, also 24k btu. They list average consumption of 2.01 kw.
Heating consumption 30k btu on the mini split is 2.7k, fyi.

For each you would have to add the amp draw of the pump in one case and the air handler in the other.

I think given a few years marine a/c will catch up with land based systems because R22 is going away. R410 is the new one and the compressors are smaller and run at higher pressures which is some of the improvement in efficiency. I think it makes them harder to start too, so that maybe the reason for soft start and all that good stuff. As it becomes harder to buy R22 parts the marine guys are going to be forced to embrace the new stuff like it or not. In A/C times are changing.
In terms of salt air- the mini split systems on a beach side home in Mexico lasted fairly well for friends. Lawn furniture needed painting yearly for rust so I guess some salt was in the air. I think they sold the house after 10 years and the system was still running. Does not mean it will work on a boat of course.