Sticker shock: air conditioner

[Suijin]

If you're buying a new boat I would suggest that you at least consider having the ducting installed by the factory, depending on the boat. Running all of that later can be a nightmare of access, trim, etc.

A 16k btu water cooled unit with all the bits is going to run you @ $2-3k retail. Installing it is not rocket science. While the ducting is not rocket science either it's time consuming to install post-production in a lot of boats.

Window or portable units are great. Until you leave the dock. Then they are a mammoth PITA.

[DotDun]

Originally Posted by smj

The water cooled ac's may be very efficient where the water is cool, but in the summer time where we are located the water temp is over 90 degrees so doesn't seem to be as efficient.
The water cooled marine ac's are also more convenient and hidden and controlled like a central home unit, so more popular.
For us the air cooled does a better job where we are located and since we don't need an ac while cruising and we have a weight sensitive catamaran and can easily remove the air cooled unit it's the best for our application.
Don't worry, the marine units won't go out of business.

This is simply not true. If you deliver the proper water flow to a water-cooled condenser, it will work up to water temps equal to air temps in an air-cooled system. The freon entering the condenser is ~150°F and only requires a 15-20°F reduction in temperature coming out of the condenser. What you are implying is the engineer/designer of the system messed up and didn't include the proper size heater exchanger, or design for enough water flow. FWIW, in a water-cooled system, it's all about water flow, the more water you get thru the heat exchanger, the more heat it will extract from the condenser. And on the flip side, the less water you move thru the heat exchanger, the less heat it will take from the condenser, hence my claim that is what you are experiencing.

[smj]

Originally Posted by DotDun

This is simply not true. If you deliver the proper water flow to a water-cooled condenser, it will work up to water temps equal to air temps in an air-cooled system. The freon entering the condenser is ~150°F and only requires a 15-20°F reduction in temperature coming out of the condenser. What you are implying is the engineer/designer of the system messed up and didn't include the proper size heater exchanger, or design for enough water flow. FWIW, in a water-cooled system, it's all about water flow, the more water you get thru the heat exchanger, the more heat it will extract from the condenser. And on the flip side, the less water you move thru the heat exchanger, the less heat it will take from the condenser, hence my claim that is what you are experiencing.

My posts were written on our experiences with quite a few different boats with different ac systems and I stand by what I say. This may not jive with the technology but in that case I can't agree with the technology. I'm glad your happy with your marine ac system, I wasn't and have gone different more pleasing routes since that time. Stay cool!

[DotDun]

Originally Posted by smj

My posts were written on our experiences with quite a few different boats with different ac systems and I stand by what I say. This may not jive with the technology but in that case I can't agree with the technology. I'm glad your happy with your marine ac system, I wasn't and have gone different more pleasing routes since that time. Stay cool!

[a64pilot]

Whatever it's worth, an airconditioner properly designed will cool its condenser with 100+ degree air or 90+ degree water.

[thinwater]

Originally Posted by Cormorant

I was curious about this part of the the DeLonghi description:

"No Drip Technology
Exclusive condensate recirculation system with NO DRIP TECHNOLOGY makes the air conditioner more efficient and more user friendly (never empty a bucket again). The washable filter is also easy to access."

So . . . where does all that condensate go? It recirculates? Do they somehow send it out with the hot exhaust?

Easy. You evaporate it into the hot air stream. Many AC units do this.

[thinwater]

I've had portable (Cruisair) and installed, and installation is worth the work. Period.

The prices quoted are userous, of course. Running the ducts can be most of the work. It's impossible to say how difficult without inspecting the boat. It just depends on the layout and where there is room. A 4" insulated duct is pretty fat.

[taxwizz]

Originally Posted by Lake-Effect

In my neck of the woods, the summer hasn't been that hot, and AC units have already gone on sale. For the house we just scored a brand new but discontinued 8000BTU window unit for $75 CDN!

WOW ! Where did you find that?
I want one too.

[a64pilot]

A way to keep from running extensive duct work is to install multiple units.
You can also run split units I think it's called, one big compressor and multiple evaporators. I've seen them often on power boats.
Good thing about the standard marine 16K unit is it's pretty standard, when it bites the dust one day it's usually easily replaced, not so much on those split units.

[GrowleyMonster]

+1 for window units at the dock. They are cheap and expendable. With a little foam insulation board or ply or beaverboard and some fiberglass, you can make a dandy cowl for it that sits on your forehatch. I don't like companionway mounts. When you are in your cups, it can be difficult to navigate over or around it.

I tried a portable but it took up too much room on my itty bitty boat, and made an awful lot of water. A neighbor mounded a coleman RV roof mount unit on his catalina and he loves it. It was free. The fan motor was froze up and we got it freed and running, and three years later, his boat still feels like a walk in beer cooler. Isn't shore power wonderful?

Agree with the others. $16k is way too much. If you are a good scrounger and a good shade tree engineer, you can put something together for well under $1k and get some nice marine grade units installed for around $3k.

Do you think you will actually use the air conditioning underway? Or at anchor? If it is just for dockside use, go with a window unit or a RV roof unit. Sooooooo cheap and simple. Some fans are a good idea, too. I got a couple of 12vdc 8" clip on fans at a truck stop and they are really nice to have sometimes. I have a 12" 110vac fan mounted on a bulkhead and blowing into my vee berth, where I sleep. Nice, with or without the AC running.

[Scott Berg]

A comment: I just replaced a MarineAir (NOT the Chinese Marineaire) unit on a 50' Chris. The previous all in one 16K unit was 31 one years old and still working (but the compressor was on it's last legs). That's three decades of full time use... the US made models like Cruisair, MarineAir (both now Dometic), Flagship, and a few others are VERY well made water cooled condenser units and they are very long lived. I don't think I had a condenser unit last more than a dozen years on any house I've owned... yes, marine ACs can be dear, but they last a long time and provide great service when properly installed... (usual disclaimers that I sell, install, and service AC's and other marine gear).

[Tx J]

Originally Posted by Cormorant

I was curious about this part of the the DeLonghi description:

"No Drip Technology
Exclusive condensate recirculation system with NO DRIP TECHNOLOGY makes the air conditioner more efficient and more user friendly (never empty a bucket again). The washable filter is also easy to access."

So . . . where does all that condensate go? It recirculates? Do they somehow send it out with the hot exhaust?

Howdy Cormorant,
Yes, that's exactly what happens, most of the condensate is 'mistified' or whatever (by the exhaust fan I assume), and carried off with the hot exhaust (which of course holds more water vapor than cool air) for the most part. It doesn't "recirculate, it is removed and overall dehumidification is quite effective. More about this below*.

The normal production of condensate, like in all AC's, happens continuously of course. A certain amount remains in the drip pan at the bottom of the unit, there is a drain plug outlet on the bottom rear that could be plumbed to the bilge or wherever.

* The (excellent, despite the Consumer Reports piece (I've subscribed to CR since about 1967 too), DeLonghi unit I cited has a very effective "dehumidify" mode. That mode changes the fan and compressor cycles around and just sucks the humidity out of ambient air. It has a quite 'smart' control system.
However, it does 'dehumidify' so well that the drain pan can fill up (under very humid conditions), the exhaust cannot dispose of it all under some conditions.
When that happens (I've only seen it once or twice, and rarely use that mode anyway), the full drain pan is detected by a sensor and the AC unit displays an alarm message on it's screen, and also shuts down (no chance of a messy leak). I mean you can't even run it in "fan mode" until you drain out the excess water. Once I just left it and after a number of hours enough water had evaporated? that I started it up (in AC mode) and it was fine.

* About that "hot exhaust". I've SWAG guestimated the airflow volume and duct cross sections, and I've taken actual temperature measurements (w/my trusty Fluke 561 IR thermometer), and reached some conclusions.
The 'cold' air produced and directed to the conditioned space is roughly twice the flow that is exhausted outside, it's temperature is always about 25+ degrees below the ambient air going in (as are most all AC units of all 'consumer' types, the term is, IIRC from AC school, "system enthalpy"?).
The hot, ducted out, exhaust is about half the cross section, possibly the volume (it may flow faster, didn't check this), of the cold flow. But, this hot air is about 50-60+ degrees hotter than the ambient air (twice the temp differential).
Actual measurements: ambient air- ~78 degrees; cold air stream at the exit vent- ~48-52 degrees; the hot exhaust air (measured at exit duct ext surface, and along it)- ~115-125+ degrees.
I conclude that the 'makeup' air required is much less than that stated by others here who have argued a 1-1 air volume ratio, with a severe efficiency penalty. It isn't nearly that bad.

I also have insulated that exhaust duct, so any heat radiation to ambient space along it is minimized (Lowes, HD, have handy duct 'insulation sleeves for sale, just wrap it on and seal, of course all joints are taped too).

IMO, these portables are still a very viable AC choice for many/most, let alone the most economical to acquire, and not too shabby to run. With some suitable care in installation, they are quite suitable, despite all the nay-sayers around here.
The power needed to run any AC unit is roughly the same, so if you can feed one, having AC is an option (and in certain places like where I am, a necessity-- (when I was young we had to get periodic medical certs in order to endure certain enviro parameters, extreme heat being one criteria).
As far as reliability, durability, mine have been trouble-free for 2+ years. If they fail, a complete replacement can be had for a very small fraction of the cost of the 'marine' ones.
And remember, they all use basically the same parts inside, even sourced from the same mfr's. AC's are a 'commodity' product now.

Like I stated, with some care, you can 'build' them into the furniture without any more 'handy' skills than those constantly exhibited by most CF people (the level of 'innovation' around here is sometimes amazing, one reason I've been around here for many years).

[Tx J]

Originally Posted by Cormorant

"--Dehumidifies while conditioning (removes 54,95 pints/24h of excess moisture)
--Dehumidifying only function (removes 86,65 pints/24h of excess moisture)"


So that's 6-10 gallons a day it has to get rid of. Just curious how it works.

Heck, at that rate you could sterilize that condensate and have a good, but fairly small, potable water supply, eh?

[DeepFrz]

I conclude that the 'makeup' air required is much less than that stated by others here who have argued a 1-1 air volume ratio, with a severe efficiency penalty. It isn't nearly that bad.

How much less, exactly?

[Tx J]

Originally Posted by DeepFrz

How much less, exactly?

Well, I may have subscribed to Consumer Reports for fifty years, but I don't have a full test lab in the garage.
As stated, I gave my best guess 'SWAG' air flow estimate, and drew a subjective (but very ballpark) opinion, like most do here on any topic.
While I can easily measure temps, the only air flow instruments I have are fairly accurate anemometers, one up on my weather station; not practical for this.
The cool outlet grille on the unit I cited is roughly 3+ times as big in cross section as the 5" diameter exhaust hose (it's only drawback is that the vent is fixed, not adjustable in directing the cool air, some others are adjustable).
The cool air comes out quite fast in large volume on 'high'. The exhaust is even faster, but much less volume I think, hence less makeup air loss (which is a practical red herring anyway).
Measuring the moving air mass isn't something most can do. If you can, I'll loan you a unit (or for a few dollars get one online-- and drifting- somebody posted a Costco link here to a portable "mini-split" AC unit that looks reeaal interesting, but it's only available at Canadian Costco's . I'm seriously considering switching my two 3 1/2 ton (2x 42K BTU) home central AC units out for more efficient mini-splits, so many choices nowadays... ).

Given the measured temp differentials, and a fair subjective opinion on relative air movements, I'll confidently say that the efficiency penalty for a carefully installed "portable" AC unit is only 10-20% over other types for a given power consumption, even a 20-30% isn't that bad.
A trivial amount, derived in a carefully considered, partially actually measured opinion; in direct contrast to all the 'shoot from the lip' '50%+loss/fall apart overnight' bullpuckies floating around here.

Like every other 'boat' thing, there is a trade off here, as I mentioned before. A 10-20% cool/power loss is trivial, IMO, given a price differential of 500-2000%+. YMMV
Given all the staid 'in the box' thinking of many around here, the choice is 'yours'.
Factor in all the other stuff (no maintenance (except clean filter), reliability, potential peril, etc) and I'll happily keep using a very cheap 'portable' AC unit(s) (but actually quite high quality), not a 'ghetto window unit' as many are assuming.
And fitting it into the interior is just another tradeoff: lose a little space, or go without AC at the dock-- a no-brainer in steaming coastal TX.