Efficient battery driven air condition for Lagoon 450 catamaran

[s/v Jedi]

Originally Posted by roetter

I know already from my previous system that I will have at least 50% more power than I use in the warm months. It is only then that I need AC. A large genset will take up too much valuable space.

I am doing this to show that it can be done. Kind of a research project.

I am still not getting enough feedback on the core of my question - energy efficient air conditioning. Most of the feed back is how to power something that is not energy efficient.

I guess I was hoping to find someone on CF from the industry share my dream and is willing to do some research on this with me.

I have already posted what I believe is the most energy efficient unit available: the 240V/60Hz Cruisair 18kBTU self contained unit. It uses less power than my previous 16kBTU unit.

What do you call a "large genset" and what is the range of light gensets that you are considering?

[CharlieJ]

s/v Jedi has provided, what appears to be, the optimum solution.

I am currently designing a 2000Ahr LFP house bank for a 60' Sun Reef cat. A significant amount of that bank's 48kWhr capacity will be used to cool up to two staterooms. Of course we will have 12 x 220A 36VDC solar panels and a 17kW genset to replenish the LFPs (they will absorb about 15kW!)

Fundamental to all of this are the 1st and 2nd Laws of Thermodynamics: "There is no such thing as a free lunch."

[roetter]

Originally Posted by s/v Jedi

I have already posted what I believe is the most energy efficient unit available: the 240V/60Hz Cruisair 18kBTU self contained unit. It uses less power than my previous 16kBTU unit.

What do you call a "large genset" and what is the range of light gensets that you are considering?

Thanks. The Cuisair would not work for me as I have to cool two cabins on each side, but often only one per side. The system would be under utilized when only cooling one. Also i would have to run large diameter air ducting along the length of the hull if i install one per side. Laggoon's approach is to put one 8K BTU Cruisair per cabin and one 16 K BTU in the salon. But then you use a lot of storage space under the beds and the noise next to your ear prevents from from having a good night sleep.

A large genset for me is one that provides more power than I can use for charging. Anything over 2.5-3 KW in my case, as I will very rarely use it. I used my portable Honda only during crossing the Atlantic. It sat unused in a locker for over 6 months during our trip. during the crossing the weather was really bad with up to 5m (15ft) swell and 2m (7ft) wind waves. With that the autopilot was struggling really hard drawing a lot of power. I

We managed overnight passages with just solar only possible during summer time and with benign weather. The new system will have three times the amount of available battery capacity and 50% more solar. So all I need the genset for is the very odd occasion of hot and humid weather with long nights or cloudy days. It just does not make sense for me to lug around a few extra hundred pounds of metal and waste perfectly good storage. A large genset would make fender storage very inconvenient on our cat.

Does anybody have experience with the chiller driven by a VFD ?

[ebaugh]

I'm not an expert on A/C, but I did read the spec sheets on the two systems proposed on the thread. I came away feeling it would be unwise to consider them hugely more efficient. 12000 BTUS (or whatever number you need) per hour has a somewhat fixed energy cost, and even that might vary over the life of the system. I hope someone can give you the silver bullet here.

On yet another boat, I owned a Mase IS 2.5 kW genset. Single cylinder air cooled Yanmar diesel. It was an interesting design, an air cooled engine, with a "reverse radiator" in the sound enclosure that had seawater flowing through it, and cooled forced air flowing around the engine. Past the "radiator" the seawater exited to a traditional exhaust elbow to cool the exhaust enough to run a normal wet exhaust. It worked about 300 hours flawlessly before I sold the boat. But it did not seem as quiet as the specs indicate. I would probably use the Honda portable if I wanted something that size.

Good luck! I hope you can find what you need in the A/C area. On the genset side, someone needs to make a bullet proof 2-4 kW either AC or DC generator, but no one does that I know of.

[Sailmonkey]

Originally Posted by roetter

Does anybody have experience with the chiller driven by a VFD ?

I've been around them in the 12ton variety. The soft start helps with the initial current draw, but the overall power drain is comparable to several split direct expansion systems, as the chiller has circulation pumps.

https://www.dometic.com/enus/America...ctdataid=85089

This is the type of unit I would install if I was attempting to do what your talking about. The compressor is fitted in the engine room and tied to several evaporators using copper tubing. Minimal ductwork is needed and you can have several zones on one compressor without the added weight and power draw of a chilled water circulation system.

[arcwi]

check polardcmarine, their volvo-based dc gensets are the lowest weight and highest performance available, designed to charge battery directly without the losses in the AC chargers, although some models can run without battery, make great diesel inverter generator.

[Emerald Sea]

Originally Posted by Sailmonkey

I've been around them in the 12ton variety. The soft start helps with the initial current draw, but the overall power drain is comparable to several split direct expansion systems, as the chiller has circulation pumps.

https://www.dometic.com/enus/America...ctdataid=85089

This is the type of unit I would install if I was attempting to do what your talking about. The compressor is fitted in the engine room and tied to several evaporators using copper tubing. Minimal ductwork is needed and you can have several zones on one compressor without the added weight and power draw of a chilled water circulation system.

Roetter
I have been at the Dubai Boat Show this week and met a owner of a new L450 where he had chillers recently installed. He had his boat delivered without a/c. The units sit astern of the engines, quite small units approx 50cm x 40cm x 40cm. He had a local outfitter install the complete unit including all the plumbing. Apparently a nr of boats in this area have made this conversation as being more efficient, less maintenance, reliable, over a/c's. Considering the searing Arabian weather here they are probably onto something! The outfitter was Portofino Marine Services LLC. .

Steve

[roetter]

Originally Posted by Emerald Sea

Roetter
I have been at the Dubai Boat Show this week and met a owner of a new L450 where he had chillers recently installed. He had his boat delivered without a/c. The units sit astern of the engines, quite small units approx 50cm x 40cm x 40cm. He had a local outfitter install the complete unit including all the plumbing. Apparently a nr of boats in this area have made this conversation as being more efficient, less maintenance, reliable, over a/c's. Considering the searing Arabian weather here they are probably onto something! The outfitter was Portofino Marine Services LLC. .

Steve

Thanks Steve. That is pretty much what I am leaning towards so far. Install chiller behind the engine. They are not too heavy and keep the noise away for. The sleeping quarters. I guess for Dubai they must have put pretty big ones in.

[Whomda]

Roetter,

Could you let us know what you finally settled on?

[rwidman]

"Efficient battery driven air condition for Lagoon 450 catamaran"

Air conditioning takes a lot of energy. Unless you're willing to line the bilges of your boat with batteries, it's impractical. You can do it but you will find it doesn't work very well. Also, consider that most boats have little if any insulation. That compounds the problem.

If there was a practical way to air condition a boat using just battery power, you would see it on production boats.

[Whomda]

Originally Posted by Emerald Sea

Roetter
I have been at the Dubai Boat Show this week and met a owner of a new L450 where he had chillers recently installed. He had his boat delivered without a/c. The units sit astern of the engines, quite small units approx 50cm x 40cm x 40cm. He had a local outfitter install the complete unit including all the plumbing. Apparently a nr of boats in this area have made this conversation as being more efficient, less maintenance, reliable, over a/c's. Considering the searing Arabian weather here they are probably onto something! The outfitter was Portofino Marine Services LLC. .

Steve

Steve,

Do you happen to remember the brand of the chillers installed in the 450s?

[luv2sbr]

Tesla Powerwall deliveries to begin this summer.

I don't know much about this subject, but I recently came across this article about a new battery being made by Tesla. The battery is intended for homes in remote areas, so they can operate 'off the grid'. Tesla says they are much 'better' than traditional batteries.

Of course, I immediately wondered if they could/would eventually be used in the marine environment. They are HUGE right now, and designed to fit on a wall in a home. Maybe they can make them smaller someday or they could stow in the v-berth.

Anyway, here's a link to the article.
Powerwall | Tesla Home Battery

[woodenboats]

You noticed the Teslas run on 350-450V?

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