Air Conditioning via Solar Panels

[Mark424]

Originally Posted by Luc bulterys

What I am trying to do is close to what Hugh did, but I am still wondering if I could skip buying a generator at all, with extra budget for alternative energy ?

While this is a new product, you might consider the Integrel Marine system that eliminates the need for a generator.

https://www.youtube.com/watch?v=p6jMN2HTlmc

The short answer is that at all RPMs other than redline, your diesel generates more HP than your prop needs to spin, so this system always makes sure your main propulsion diesel(s) are optimally loaded and excess HP your prop doesn't need is used to make electrical power that is put into your battery bank.

Search for the other thread on Integrel where some folks built their own less automated version to achieve the same goals.

I'll throw out one more option for you. Have one side of your cat a standard diesel saildrive (perhaps with larger engine) with an Integrel or similar system, use the generated 48V DC to drive an electric prop in the other hull. For long distances you may only use one drive at a time. You can also use the electric side to generate power under sail and augment your solar to fill the battery bank.

[Q Xopa]

Originally Posted by BigBeakie

The Eniquest PowerMaker Marine Cruise 16kW 48V DC genset is not listed on their website. It is based on a Yanmar 3YM30AE and is milspec in performance and design, meaning it has amazing up-time reputation. They sell mostly to the military, telco, and industries that need generators operating in harsh and remote conditions that need high reliability & up-time. I got ours after I met a guy who is involved in procurement for Oz military and he was telling me how reliable they are. Also other cruisers who said it was the best piece of kit on their boat, which you tend not to hear too much about other brands....

Eniquest do all their own design and engineering on the electrical side, do their own windings to very high spec, etc. An impressive company, and very helpful to us.

There has been more demand for the 16kW recently with the uptake of EP in Australia so the 16kW is becoming more popular. It puts out a true 15kW at full operating temperature running at 1,800 rpm. We got one of the early ones, it's seriously good.

Hmm interesting.

I wasnt aware of these guys previously. Coincidently I've recently put my own version of pretty much the same thing. Basically a 2YM15 with a brushless 11kW 28VDC aternator.

I see their 6kW DC gen is pretty much the same thing Yanmar eng etc. I see they are selling theirs for $13,883 AUD.

I have almost spent that much with a new motor and especially a custom drive adaption.

Now I know how to do it if I ever did another one I could do it significantly cheaper.

I have got all the bits together for mine but still in the midst of a refit so havent operated it yet.

Its encouraging to hear that others seem happy with them and they seem to perform well.

[Simi 60]

Originally Posted by CatNewBee

we have 1650Wp solar 5x330Wp BenQ panels, 80..100A at 14V output, good for one A/C unitbto run on solar

Yeah but where and how big?

An a/c in Tasmania can keep a boat cool but could it do the same in Thailand?

I seriously want to know as I have no need for a/c at the moment in Australia but do plan on going 2000nm north where it'll be a tad warmer.

[CatNewBee]

Originally Posted by a64pilot

But what charges your bank then?

well, the maximum energy harvested from the 1650Wp solar panels per sunny day is around 8kWh, the battery delivers 15kWh from full to empty (it is a LiFeYPO4 built from 4 Winston 1000Ah nominal cells, battery is 13.6V/1000Ah, they in fact deliver 20% more - 1200Ah - than the nominal value between full 3.60V and empty 2.9V).

You can chose how to use this energy.

When the battery is full, and the sun is shining, you can run the A/C instead of idling, or make hot water.

During the day we use to stay outside in the shadow or on the water, we cook, bake, make water and ice cream or ice cubes for the sun downers. This keeps the LFP battery around 80..90% SOC end ensures all energy from the sun is used in BULK, no idling at ABSORPTION or FLOAT.

When we go to bed, we run the A/C on battery for 1..2 hours in the master cabin to chill down and sleep comfortably. All this on solar alone. Solar recharges this easy the next day.

Btw, the convection oven uses much less power than the induction hob, also the 5kVA Victron inverter can handle all devices when not full throttle in parallel, no problem at all. We can team up a Mastervolt MasSine 2000 inverter along with the Victron Quattro to get 7kVA, but never had to yet.

Of course you need proper cabling, that can handle up to 500A peek to the inverter.

[Luc bulterys]

Originally Posted by Mark424

While this is a new product, you might consider the Integrel Marine system that eliminates the need for a generator. ...

Thank you very much for this suggestion, Mark424. I will definitely look into it, because this matches exactly with my ideas. That the info is not coming from a marketing guy, but from well appreciated Nigel Calder, helps also.

[Luc bulterys]

Originally Posted by a64pilot

Making heat, or even moving heat around takes lots of power, but especially making heat.
If you plan on cooking electrically, and especially if that involves an oven, that is going to be tough, real tough to do on Solar alone.
...
How many thousands of watts does an oven consume? You need of course to cover that and more with your panels.

Thanks for your thoughts, a64pilot. I do understand your concerns, of course.

Since it is a reversible AC using seawater, heating will take the same amount of energy as cooling. And of course, this will never give the same results as heating with diesel. As long as the seawater temperature is not below 10°C, it should work well enough for what we are planning to do.

I am looking for a small oven in the range of 2,5 - 2,7kW. And I can live with the idea that, most of the time, using the oven will need some extra supply of energy. That's where the suggestion of Mark424 is interesting, I think. But of course a generator could solve this too.

[valhalla360]

Originally Posted by Luc bulterys

Since it is a reversible AC using seawater, heating will take the same amount of energy as cooling. And of course, this will never give the same results as heating with diesel. As long as the seawater temperature is not below 10°C, it should work well enough for what we are planning to do.

Actually depends on the temperature differentials. We noticed a distinct drop in cooling ability from spring on the great lakes when water temps might be 40-50F to late summer when the water could could be 80F (marina out of currents with shallow water)

If you are on the north sea:
- Cooling in the early summer, you might be seeing water temps around 45F. Cooling with a goal of 70F will be quite efficient with a favorable target differential of 25 degrees.
- Heating in the winter, water temps might drop to 35F while attempting to heat to 70F with unfavorable 35 degree differentials.

Obviously, if you are in a tropical area, it may favor air/con over heating depending on the water temps.

[Luc bulterys]

Originally Posted by CatNewBee

well, the maximum energy harvested from the 1650Wp solar panels per sunny day is around 8kWh, the battery delivers 15kWh from full to empty (it is a LiFeYPO4 built from 4 Winston 1000Ah nominal cells, battery is 13.6V/1000Ah, they in fact deliver 20% more - 1200Ah - than the nominal value between full 3.60V and empty 2.9V).

You can chose how to use this energy.
...

Very inspiring experience, CatNewBee.
Could you tell us what climatic region you are talking about with those numbers ?

[CatNewBee]

Originally Posted by Luc bulterys

Very inspiring experience, CatNewBee.
Could you tell us what climatic region you are talking about with those numbers ?

Mediterranean sea / Ionian Sea / Adriatic Sea South Europe last summer...

[a64pilot]

Originally Posted by Zzmeyer

What generator and how do you have it set up? I would love to have my generator come on and shut off based on house battery charge. Would solve lots of problems

There are many answers to this, if your inverter Charger is a Magnum, then all you need is the AGS kit, AGS is automatic generator start of course.
Apparently there is even a stand alone version
https://www.magnum-dimensions.com/au...rt-stand-alone

The kit for the inverter Charger can be had for under $200, I’ve considered it, but am uncomfortable with an engine starting automatically, old fashioned I guess

[Rule303]

Originally Posted by Simi 60

Yeah but where and how big?

An a/c in Tasmania can keep a boat cool but could it do the same in Thailand?

I seriously want to know as I have no need for a/c at the moment in Australia but do plan on going 2000nm north where it'll be a tad warmer.

Just so happens that I have a Hobart registered 54' Power Cat that now lives in Thailand. We run two domestic split system 240v Reverse cycle A/C units pretty much 24/7. On the Inverter panel, they show 1200W draw during the day, 1600W for a few hours when the sun comes directly in the back, and around 800W at night.

42C outside, 20C inside.

[LoudMusic]

Originally Posted by Hugh Howey

When the sun is blasting, you get free air conditioning. And by free, I mean the panels and batteries cost an arm and a leg.

Sailing is the most expensive way to travel for free

[CookiesnTequila]

Originally Posted by Hugh Howey

Yup. It's possible. It's not cheap, but it changes life aboard.

A few years ago, I commissioned and launched a 50' catamaran with 1.75kw of solar on the roof and 900Ah of 24V lithium batteries. The batteries and inverter proved beefy enough to run two AC units for a few hours at a time, or a single AC unit for 6 or so hours before the generator needed to kick on. I also elected to install a DC generator instead of an AC generator. Everything on the boat is designed to run off the battery bank. The solar array, engine alternators, and DC genset are there just to dump amps into the batteries.

It was an amazing setup. Crossing the Atlantic -- 6,000 miles from South Africa to the Caribbean -- the genset kicked on twice. And we only motored for half a day across the doldrums. The joy of lots of solar and big batteries allowed for life aboard to resemble apartment living (big screen TV, fridges, freezers, hot water, even AC for brief spells).

This was a far cry from my first 5 years living on a boat, where I didn't have a shower or toilet. Nothing wrong with either kind of sailing if you ask me; this thread is about what's possible, not what's necessary.

When I got to Australia for my first refit in three years, I decided to add more solar and two more batteries to my current system. Part of the reason for adding the solar was to extend the bimini out to either side for more shade and rain protection in the cockpit / helm. I was also hoping (dreaming, really) of having a system where AC can be run during sunny days without draining the batteries.

This isn't to sit in the AC on beautiful days; it's to control humidity, mildew, and the wear-and-tear of moisture and a marine environment on personal electronics, clothing, bedding, etc. I live full-time on my boat, and I spend a lot of time in the tropics at anchor in very remote places. Energy independence without sacrificing comfort was the pie-in-the-sky dream. This week, I saw that it is possible.

With 4 more high efficiency 350W LG solar panels, total wattage is now just north of 3kw. Two more Mastervolt batteries gives the 24V bank a total of 1,260Ah.

On a very sunny and abnormally humid day in Australia, we launched the boat and ran the AC for the first time. With the compressor running, the solar was still putting over 20 amps into the batteries! Cooling and dehumidifying the boat while topping up the batteries at the same time!

What I love about this setup is you only need the power when you have the power. When the sun is blasting, you get free air conditioning. And by free, I mean the panels and batteries cost an arm and a leg. But once you have them, life at anchor can be whatever kind of life you prefer.

Battery and solar prices keep coming down while efficiencies go up. I hope what I'm seeing on my boat becomes the norm one day. Fewer generators being installed, more electric engines, more happy cruisers who are out enjoying the nice weather instead of doing the bedding again or treating the forepeak for mildew.

Firstly, awesome, and hats off to you!

We have a Catana 50' sailing cat, just installing 600ah Li @24v and will have 2.1kw solar by spring (1.5kw now).

Questions: how much do you need to cool to get the dehumidification you want?

And, what type and how many BTUs ac do you have, and are you happy with it? Would you do anything different?

We are installing AC next year also before we head to the tropics, primarily for dehumidification, and some comfort of course. When we lived on land, we used to only cool to 4 or 5 degrees C less than ambient.

Cheers

[noelex 77]

Originally Posted by Rule303

Just so happens that I have a Hobart registered 54' Power Cat that now lives in Thailand. We run two domestic split system 240v Reverse cycle A/C units pretty much 24/7. On the Inverter panel, they show 1200W draw during the day, 1600W for a few hours when the sun comes directly in the back, and around 800W at night.

42C outside, 20C inside.

Power cats have lots of room for solar, but at a rough estimation you are using 2,000 Ahrs (@ 12v) a day just for the A/C.

[a64pilot]

A small unit running continuously will do a better job of dehumidifying than a larger unit that cycles.
It will also do more cooling with less power if efficiency is the same, reason is when a unit first starts, it consumes energy for quite some time before it actually begins to cool.
Same as with refrigeration, cycling is inefficient.

Using Nolex’s estimation, and I do believe it to be correct, you need 6000 W of panels to deliver 2000 AH at 12 VDC.

Of course it can be done, it’s simply a matter of scaling.
What does the number of required panels cost installed, along with a bank big enough to store the energy, remember that 2000 AH just covers air conditioning, it doesn’t charge anything.

Then compare the costs and disadvantages of all that Solar against a small built in Diesel genset, and I think you’ll see why it’s not often done.