Running an Air Conditioner From The Sun - The Holy Grail

Ok, thanks. Ive seen couplings and I understand the basic idea of the hook up of the small engine. I am on a solar power forum to get some input from people who know solar like we know boats - where most members own solar arrays. I'll report back to this thread with any new facts.

Who knows, of I have to still use a generator, maybye that is all I will use since having both can be expensive.

 

"If there is a more efficient way to run a generator, I'm interested in hearing it though."

Start with USED, and variable speed.

A used 2 or 3 cylinder Reefer engine will run $300-$500

A rebuilt Bus 300A 24V alternator perhaps a grand .

A good machine shop can end mount if $1000?

Because the unit can be throttle controlled , a welding shop throttle will do fine.

Now your noisemaker costs are way below your estimate.

What ever batt set you think is fine , but I prefer ones that can be instantaly ,cheaply replaced , Sams Club or Sears.


The big question for every solar system is 4 days of rain????

In a big cat you could mount the noisemakers in the fwd portion of the vessel, behind a well insulated bulkhead . Perhaps a stall shower next would create even more sound barrier?

My problem is FAILURE , you could dump $40K into a solar acre and if it doesn't work , what then?

You are back to running the noisemakers , wgich of OTS will be AC , lousy for conversion to charge a huge batt set.

FF

 

Quick question, Fred.

Thanks for the tips. This is becoming more interesting.

How do I match the variable speed of the small diesel to the load? Honda does it on the eu2000 generator. Can I do the same?

If I can, this would reduce fuel consumption and make it actually cost less than solar, even over the long haul.

Because I have outboards going on this boat, I have empty engine rooms that I can put this small diesel in. I also have two forward lockers like you are suggesting and they do have heads directly aft of them, so no problems on location.

 

You can have both just reduce the Solar side a little and let technology catch up. I used the solar really to top off batteries, and so I don't have to charge them everyday. They are also good for knowing that I can always have some power in the middle of no where without the generators.

The little diesel has two alternators as a way to control charging amount.
I am also using relatively off the shelf truck alternators. Though I am looking at better ones.

Ask that guy Charles Kimbal, I told you about. He is trying to sell you something but he knows his stuff, been doing it for 20 yeaars. He sell a lot of solar for export and is honest. Be careful of solar experts that are trying to push an agenda rather than something that works in the real world. As you can see on this forum there is a lot of those. Which Solar forum are you referring to? I would also like to follow it.

I find that energy consumption, like money is a two prong approach. You have to save it, and make it. I am reducing power in every component on board. New technology has let me eliminate thousand of watts in demand.

Everyone looks at the big demand items, but remember an item that use 10 watt that is on 24 hours a day is a big drain. If you have 15 of these, this a major deal. Also controllers, dimmers, transformers, tool chargers all consume electricity. These phantom electricity users are all around you in a house.

 

Yeah, I understand electric systems inside and out. Everything I do with systems on boats is for maximum efficiency.

Just look at all the painful propulsion threads I have on here. Even checking the drag of a saildrive. Talk about being anal about efficiency! Ha ha ha

Technology has changed. Look at the 1.5 kw, 36000 btu air conditioniner as an example.

I am evaluating all possibilities because the last time I did a system was 2 years ago. You must do the numbers fresh every time, as products get better and better. I will just use a generator and lifep04 batteries if solar, in the solar forum, does not work. One system for simplicity and weight concerns.

Basically, if I'm forced to go the generator route, that is all there will be. No extra solar panel weight. Remember, this entire boat is designed and built for maximum efficiency, which means as little weight as i can get away with.

 

In my humble opinion, on a boat I believe in KISS, and stay one set below state of the art, and I have three of everything. Well that is why I went with a monohull so I can have displacement to carry all my spares without it affecting me as much as CAT. I see most long-range cruising sailboats in the 40'-50' with all of the above. They have wind, sail and the diesel generator or a honda on deck.

 

I have to disagree with this. Apart enthusiastic casual visitors, I don't see many solar-power promoters in this forum (actually, can't recall any), which is mainly made of pretty rational and (at least apparently) experienced people with argumented advices. Don't see too much agenda here, fortunately.

 

That's the truth... that's the normal way of doing things.

I'm creating a (hopefully) very special sailing machine that will give one heck of a ride under wind power.

The reason I have so many posts, in general, is that I want to catch every angle. I have several competing features I need to attend to:

*Weight (or efficiency under sail)
*Drag (efficiency under sail)
*Economics (need to be able to afford the costs over 10 years - this is a business)
*Comfort (people paying several thousand dollars are going to want to have the best possible vacation)

So, when I go around and around on these forums, it's to slowly, but surely, visit every option and whittle them down to just one.

Above all, efficiency is most important to me though. That starts with efficiency under sail, then moves onto energy related efficiency. That's how Daiquiri with one sentence, got me to really stop on the solar for a moment and look more closely. He mentioned weight and I immediately went back to priority #1.

So, I am curious how to make a control system for a diesel engine that will vary the diesel's RPM to match the load. Anyone know anything about this? If I can do this, I could actually stop looking at solar, since that would make it light weight, fuel efficient and able to provide comfort for the guests.

Any ideas?

 

Although you feel Weight is #1 priority, and comfort #4, your paying guests would reverse the order. Whilst too much weight makes a cat a dog, there are some interesting observations from real world. Cruisers with lightweight flyers aren't much faster than their heavier competitors. Probably because the lightweight boats have a lot of stuff on board. Like you will have to have, to be able to give the required comfort level.

Even more amazing is the Lagoon 440, displacing 13 tons and likened to a Winnebago with sails on another forum. A couple of owners have achieved 21 knots on these things, with all the comfort anyone would want.

Bottom line? Your hull design has a design load limit. Undershooting design load probably wont give you much benefit. Overshoot and you will have a dog. Where does your spreadsheet have you re:load? You may well be able to have both genny and solar if enough savings elsewhere.

The basic idea is a load-sensing DC generator. Glacier Bay was doing it for the truck refers. It is the principle that Honda use, coupled with an inverter to get AC.

 

Yes, this is the crux of all of my problems. I am trying to design systems for a boat that gives a high performance sail (in light air). This is in direct opposition to providing every comfort under the sun. It is a bit maddening at times trying to find a balance between the two diametrically opposed philosophies.

I can remember an apt quote from the Simpsons many years ago. Agnes Skinner (the principal's mother) is in a grocery store and she says to the bagging clerk in a shrill yelling voice, "I want all my groceries in one bag! But I don't want it to be heavy!"

Seems about how I feel most of the time trying to strike the perfect balance between performance and comfort.

Yes, achieving 21 knots with a Lagoon 440 is an absolute miracle, requiring near hurricane force winds. I would be in tears if my boat performed anywhere near as bad as one of those. I will not accept a boat that sails that poorly. What you are missing (and most people miss, so it's not to say anything negative) is that a fast boat is not about going 20 knots. It's about going 7 knots... in 7 knots of wind, while everyone else is motoring. That is what a fast boat is for. It's not for breaking speed records on the top end. It's all about efficiency and for that, I need to keep the weight off the boat.

While having the small diesel and the small solar would be attractive, it would seem that the system would weigh much less if it were just the small diesel. You run it for a very short amount of time for house power needs, or continuously if you need to run air conditioners. Where this makes some sense is that I can charge at C with LiFePO4 batteries. Yes, that's not a typo. They accept charge at C. So, with a 600AH bank, I can charge at 600A. Pretty neat. Also a huge efficiency gain over any other type of battery out there. So, the solar isn't as necessary to charge these batteries as it would normally be in the old days.

I do need to shed every single possible lb/kg from this boat in order to have the best boat I can. That is one of the design goals, or the SOR.

My customers will enjoy a nice, quiet sail on days when other boats are unable to provide one. Goal #1 in the build.

11,900lbs is boat weight at launch. Fully loaded displacement is 18,000 lbs. Every bit closer to staying at 11,900lbs I can get will give me more of an edge in light wind.

You can't really make up the weight in the hull construction. Where you can make it up is in fit out.

Systems are probably the heaviest part of a fit out, given you are using cored panels for interior construction. This is where you can save weight, IMO.

Right. Exactly. Specifically, it's called a load demand throttle control. How do I make one for a diesel engine I install?

 

If you were Chinese you would buy a Honda and copy it. But its the wrong power range anyway. But it should be simple for an Electrical Engineer familiar with process control. Maybe those guys inhabit a different forum.

You may not need it. Just have a DC only genny that charges your LiFePO4 bank. The bank was always going to be big enough to run AirCon at night if needed anyway. Charging at max. will limit engine run time, get best efficiency. By monitoring charge state of the bank, you could plan when you would need to run the genny. You can keep it really simple - prob, save weight too.

 

The new generation of hybrid hot water producing solar panels might be of some use-
I am currently trying to get some out of the only company who seem to produce them -for application to a riverboat project-
the water cools the panles increasing their efficiency-

or perhaps if you cycled the airconditioning cooling through the back of the panels somehow the efficiency might pay off? the hotter the sun the less efficient the panels get....
you could get those ecofans for wood stoves and fluip themover and youve got free energy running fans for the aircondtiioning systems(thermoelctric peltier driven jobbies)
havent read the whole topic but presumably someone has turned you on to MPPT controllers and the value of good charging systems-?
Or what about vented panel backs with cooling running by and alongside the aircon?
The c-tek solid state chargers are just as good as systems that will cost you thousands if you botch them together too.

btw anyone want to invest in a solar river boat project?
interesting to see soemone trying to get coolwith solar- im planning using wind turbine dumploads and the clever hybrid panlels to keep warm in winter and giveme electric- hopefully drive too in the summer!
vandals just burnt my old wooden pinnace and all my tools (a week after i moved in-and hadnt sorted the insurance out doh!)
so im back to filthy diesel and steel cruising.
anyone got a spare cat hulll and /or £40,000 lying around?
Its a proper project if we can get the funding- with motors from the tt winning bike and the liveaboard focused hotwater+electricity hybrid panels,
my solar guys talents are really are wasted with him converting steel narrowboats to 100% solar electric drive....
he manages it somehow as people only want tomotor when the weather is good and you only need four knots on the canals!
but still ...1.5kw of panels pushing around 2o ton of boat....

needs edit but i keep pressing the post reply button instead of save and have doen it twice akrelady-just trying to get all the ideas down...

hmmm carbonfibre narrowboats....

 

I would dearly like to see an answer to this question as well. Something I can buy, not something one of my electronics engineering friends would have to build for me, by preference. If it has to be built, a circuit diagram known to work and details on mechanical hookup to throttle control. I know the mechanical stuff would only be applicable to one engine but seeing it done once makes it a lot easier to do the mechanical engineering stuff to a different engine.

My current plan for my requirements is to buy a Honda petrol genset & keep it in a deck box, but that won't work for you.

PDW

 

http://www.annainc.com/pdfs/genBasics.PDF
http://www.era.lib.ed.ac.uk/handle/1842/4781
http://scholarworks.umass.edu/dissertations/AAI9639021/

 

This might be an easy work around. Say the DC generator is sized at the proper size to run several small air conditioners (always more ideal, as Mydauphin pointed out, though not as efficient). If the DC generator was sized to make just a little more power than the air conditioners need if all on, and the battery bank was sized at the same size as well, you could run the DC generator at full power output all the time without wasting energy.

To put it another way, there would be modes of operation:

Air Conditioning Mode: DC generator makes all power required for the time when all air conditioning is in operation, plus a tiny bit extra for galley and whatnot when the air conditioners are going. No draw on the battery bank, except during impulse loads (microwave, hair dryer, locked rotor on the AC). Let's assume it's 4kw to run the air conditioners. We would make 5kw instead, with any extra above the ACs going to slow charging of batteries and/or other small AC loads.

Battery Charging Mode: Assume a 5kwh battery bank and just dump 5kw into the bank. Run for an hour and you're done. Maybe a few more minutes for losses, but essentially, you can fill the bank in an hour.

Watermaker Mode: Just like air conditioning mode. Could even be run at the same time as air conditioning since I plan to have a very fast watermaker. Any power draw over 5kw would be made up by the battery bank.

Plan would get around the need for a variable speed generator and allow shorter generator runs instead. Would also create a sizable buffer for the loads (5kw buffer via battery bank). Would need to get, basically, a 5KW inverter, but the battery bank would be 1/3 the size I was thinking with the original solar setup, plus no vast array of 44lb solar panels.

I do believe this is the lightest weight setup possible. Good thread!!!