Newer technology A/C systems

[a64pilot]

It says it’s a BLDC which means of course a brushless DC motor, which is the most efficient motor I know of for consumer use, it also appears to consume 1000W for 16,000 BTU, which is about 32% more efficient, roughly, but it has essentially no start surge, or claimed anyway.

If you get them, I’d be interested in a report.

[TassieBloke]

Originally Posted by TCM1968

I have a couple reverse cycle A/C units that need replacing. I am interested in the newer technology units that run with variable speed inverter compressors. I am curious as to why there seems to be little info on suppliers here in the U.S. Why hasn’t this technology become more mainstream yet? I was looking online at the advertisement of the Dometic Turbo units and this has been out since 2007. Surely in 12 years someone has improved their design. I don’t want to drop several thousand on replacing units with 12 year technology only to have them become the old style a year later.

I went through the same process a few years ago.

In the end, I converted a reverse cycle Daikin Split system to fit into the space I had. The biggest problem was where to fit the outdoor unit. So I got rid that, and made all my own piping to water cool the condenser. Now we enjoy a 8KW system that is all the latest inverter technology with Bluetooth control and all. I kept all the electronics to control the system. To run the refrigerant piping was a pain, but it was worth it.

Since the water-cooled condenser is so efficient, all winter it never drew more than 5amps@240V. Normally once the airspace is at temp, it draws about 2-3amps which theoretically could be run off a large house bank. The inverter tech is a huge change to what a 'normal' AC system draws.

Daikin and others now make multi head systems. I don't how how big your boat is, but this could be a solution by having the indoor units in each cabin with a central 'outdoor' unit location. This gets around running ducting everywhere, and the inherent hygiene problems with ducting.

PM me if you want more details.

[TCM1968]

I have seen this web site and I suppose I’ll just have to call them. I was really hoping there was someone here with actual experience with them instead of just relying on the sales pitch from the dealer. Because I am concerned that what was said in the first reply may be true in which case they may not be worth investigating yet.

[fivecapes]

http://www.cruisersforum.com/forums/...-206103-2.html

[TCM1968]

Originally Posted by fivecapes

http://www.cruisersforum.com/forums/...-206103-2.html

Thanks this is exactly the info I was looking for. I guess I should have done a better search of the forum first.

[CaptNemoO2]

Originally Posted by TCM1968

Do you happen to know the cost of the unit? Although I need 120v not 230v.

I spoke with the US distributor at the boat show">Annapolis boat show. The 16k unit was $2900.

[Chotu]

Originally Posted by TassieBloke

I went through the same process a few years ago.

In the end, I converted a reverse cycle Daikin Split system to fit into the space I had. The biggest problem was where to fit the outdoor unit. So I got rid that, and made all my own piping to water cool the condenser. Now we enjoy a 8KW system that is all the latest inverter technology with Bluetooth control and all. I kept all the electronics to control the system. To run the refrigerant piping was a pain, but it was worth it.

Since the water-cooled condenser is so efficient, all winter it never drew more than 5amps@240V. Normally once the airspace is at temp, it draws about 2-3amps which theoretically could be run off a large house bank. The inverter tech is a huge change to what a 'normal' AC system draws.

Daikin and others now make multi head systems. I don't how how big your boat is, but this could be a solution by having the indoor units in each cabin with a central 'outdoor' unit location. This gets around running ducting everywhere, and the inherent hygiene problems with ducting.

PM me if you want more details.

Any interest in sharing how you did the condenser cooling?

This was a brilliant idea!

[TassieBloke]

Of course.

Used a Packless condenser coil. I sized it for the output of the compressor, and the expected water temp of up to 35C. This is also determined by the circulating pump flow which I needed to be around 15-20lpm.

I took all the electronics out of the outdoor unit, most of the cabling to the compressor and sensor wiring was long enough, had to lengthen a few, but the is easy. I mounted the PCB in a seperate housing in the first iteration. All the wiring connectors are colour coded and unique, meaning you cannot plug the wrong sensor into the wrong PCB plug. I took photos of it as I took it apart for reference, but barely used them.

The hardest part was custom making the refrigerant tubing around the compressor to the coil. This is by no means a huge task, all you need is a 1/4" and 1/2" pipe bender, a bunch of R410 fittings, and a MAPP or Oxy set.

I used as much copper as I could from the unit, and I needed only an additional 3m of tubing.

You should use Nitrogen gas flow when brazing, and for pressure testing. There was sufficient R410 in the system as these come precharged.

It started up first go, and ran for 12 months without issue. I did have to adjust the pump for water flow to keep the coil from freezing during the heating cycle, but I was being anal about it.

Hope this helps.

[Chotu]

Tassie:. Thank you very much for sharing that. Not sure if everyone appreciates what a huge leap this is in efficient marine air conditioning.

[Pelagic]

I have 1040 Ah batteries @ 24v + 1673w of Solar

Seems to me that with a large 24v house bank and sufficient Solar a 24v Air Con unit like this would make optimum use of Solar, when your SOC is at 100% by noon

https://youtu.be/JqiUzEEWIbg

[ranger58sb]

Originally Posted by TCM1968

I have a couple reverse cycle A/C units that need replacing. I am interested in the newer technology units that run with variable speed inverter compressors. I am curious as to why there seems to be little info on suppliers here in the U.S. Why hasn’t this technology become more mainstream yet? I was looking online at the advertisement of the Dometic Turbo units and this has been out since 2007. Surely in 12 years someone has improved their design. I don’t want to drop several thousand on replacing units with 12 year technology only to have them become the old style a year later.

Originally Posted by TCM1968

Thanks for the responses. I have 5 units on my boat and was hoping that these newer A/c's would allow me to run all five with less amp draw as I can only now run 3 at the same time while on gen power and 4 while on shore power. But I think my main issue is start up amps so maybe I would be just as well off with the Dometic Turbos and install easy start soft starts on them?

FWIW, this season we replaced our two 17-year-old Marinae Airrrrr Vector Compact units with the Dometic Turbos (originally named Vector Turbo, when introduced by Marine Airrrr, before they were acquired by Dometic I think).

The new units do seem more powerful (more air flow), quieter (although maybe because our earlier compressors were getting louder), and the drain pan improvement will probably be a good deal.

Our units don't start at the same time and the delay duration is programmable; is that a "soft start"?

Anyway, so far I'm pleased...

-Chris

[TCM1968]

Originally Posted by ranger42c

FWIW, this season we replaced our two 17-year-old Marinae Airrrrr Vector Compact units with the Dometic Turbos (originally named Vector Turbo, when introduced by Marine Airrrr, before they were acquired by Dometic I think).

The new units do seem more powerful (more air flow), quieter (although maybe because our earlier compressors were getting louder), and the drain pan improvement will probably be a good deal.

Our units don't start at the same time and the delay duration is programmable; is that a "soft start"?

Anyway, so far I'm pleased...

-Chris

Compressor motors can a do draw 7 to 10 times the running amp draw during start up. They want to be at full speed and torque the instant you apply power. A soft start device will control the voltage and amperage during start up so that it builds up to full speed and power gradually. For comparison think of it as the difference between a car starting from 1st gear and gradually going through its gears to get to cruising speed vs. a Drag car dumping all that torque and HP instantly from the instant the light turns green. The torque and HP required to maintain top speed isn't that much but the drag car needs an engine with enough torque and HP to get to top speed faster. Once at top speed there is considerably less torque required to maintain speed. Consider all the stress the the drag car puts on the transmission, drive shaft, axles and tires dumping all that torque at once like that. The life span of those parts is shortened dramatically. Well the same can be said for you A/C compressor, when it starts up it want to be at full speed instantly and that means your power source needs to have more available power (why your generator lugs down in RPMs when the A/c starts.)
You can add a soft start device to your A/c for less than $200 dollars, so it just doesn't make sense why Marine A/c manufacturers don't design this into their units to start with as it would be even cheaper if built into the OEM system.

Now as far as the new systems my OP is referring to not only to they already have a soft start but they are variable speed. This means that instead of the compressor running at either off or full speed that once your room temperature is reached instead of turning off and allowing room temperature to rise a couple of degrees and then starting up again it just slows down the compressor to a speed require to maintain the temp where required. It uses considerably less energy to maintain that slower speed than to continually start and stop from from full speed. This I know as a fact from switching from a single speed swimming pool pump to a variable speed pump. I can move twice as much water at close to 1/2 the electricity usage with the variable speed pump running slower even though now because the pump is running slower it is running longer to move the same water. And that is what I am hoping for with the A/C units.

[a64pilot]

Well it is off the top 32% more efficient as it draws 1000W as opposed to my 1320W.
However it’s also variable speed so as long as 16k BTU isn’t needed it can slow down and use less power where a standard shuts down and uses none.
Motor wise it’s a BLDC and they are extremely long lived motors, I’d be interested to know if the fan slows down with the compressor too to reduce noise.
I also wonder can you manually set lower outputs or is that only automatic, it has an eco mode, but can you set higher manually as eco is very low power. Probably be good for night though.
It’s weak link is the electronics, but nearly everything has electronics now.
It’s also apparently twice as expensive

On edit looking at the spec sheet again, it’s efficiency gain at 16kBTU is slight, it pulls 10 amps to mine pulling 11 and on mine that includes the water pump. So it would seem it pulls less power only when the cooling capacity is reduced, or it’s very inefficient running wide open or both.

[GordMay]

In addition to the previously noted improved efficiency; variable speed A/Cs provide a consistently comfortable temperature (no highs & lows), and a variable speed compressor's longer run times dehumidify your home more effectively, than the relatively brief cycles of a single stage unit.
One of the biggest problems with single stage compressors is that they're not running continuously.
Relative humidity increases whenever the AC isn't on, making you feel hotter and more uncomfortable. As a result, (/w variable) you feel comfortable at higher temperatures, and don't have to set your thermostat to a lower temperature. This is especially acute when an air conditioner is oversized, as they often are.
Since variable speed units run more frequently (near constantly) , they also filter your indoor air more effectively. More air is cycled through your air filters, resulting in a lower volume of air contaminants.

[a64pilot]

Most every boat AC’s fan runs continuously, moving air continuously across the coils and through the filter, so most of those advantages are diluted some.
Temp swings depend on the hysteresis of the thermostat, even in variable speed compressor equipped AC’s there will be hysteresis in the thermostat.
These AC’s will be in effect very similar to a Refrigeration system equipped with an AEO module that can vary the compressors speed based on load, even with an AEO module there are compressor off times, much reduce but they do occur.