Solar Hot Water

[Owly055]

     One thing I have not run into is serious solar hot water heating on sailboats.   Of course the black plastic solar showers are out there, and are cheap, but that seem to be about the extent of it for the most part.  The reason is obvious.  The sails can be virtually anywhere in relation to the sun, making anything solar problematic at best.   

     Frankly I love free energy, and the sun is the source of virtually all the energy we use except nuclear..... which I wish would just go away.     The boat I'm looking at of course, being a trimaran, has a lot of places where a person could mount these or PVs, and on a long passage, taking the time to go out to the amas and redirect solar PV and water heating panels to match the tack and time of day would not be an ordeal, just a daily chore.

     Battery storage is expensive, and maintenance intensive.  In my mind the ultimate storage medium is water.......... heat it or freeze it while you have energy to burn instead of storing it and stupidly running a refrigeration unit on batteries just as you would a refrigerator in a house.   A refrigerator is in fact just an icebox that idiotically lacks storage, resulting in the need to cycle frequently.

      Vacuum tube solar heating is extremely efficient, and develops high temps.  Small circulating pumps and temp controllers take very small amounts of energy...... while you have "energy to burn".   

     In my opinion you could use this energy for much of your cooking....... or at least that's my opinion since I began playing with Sous Vide, which is a process that cooks things at very low temps for long periods of time.  Meats at the low to mid 130's, fish at less, root veggies at higher temps... as high as 180 for spuds.........though I'm looking for the bottom end on that one, and the texture at different temps is an interesting experience.   The beauty of this is that you can throw the food in at a regulated temp, and just forget about it until you're ready to eat.  No over cooking because of the low temp, no starting up the stove and nursemaiding.   You put your food, spices, etc in a plastic zip lock bag and use the displacement method to get rid of air, drop it in and forget.    It's not the answer for everything, but it can reduce dependence of fuel.....and that's a good thing.

                                                                                        H.W.

[lance on cloud nine]

I think a person could make a great solar water heater by slowly circulating the water through a system with a small timed pump. Where it held it in the panel or shower bag the appropriate amount of time before sending it into the insulated storage tank.

[ralay]

Our boat was originally built to have a permanent solar water heater setup.  We don't have a cabin (flush deck), but we have a series of other short structures.  Butterfly hatches with a propane locker between the "wings.". Aft of that there used to be a shallow deck box with a plexiglass lid.  The interior housed a dark tank for hot water.  The PO said his problem was scalding himself in the tropics.  He needed to add cold water before it could be used on skin during the day.  If the goal is to have hot water for cooking though, it sounds like scalding might be just the thing. The whole system was ripped out by the time we got the boat, so we use a camp shower. 

There was a time when I thought about saving money on propane by doing some solar heating/cooking.  I lost interest when I realized how our eating habits complicate the situation.  In the summer, when there's lots of solar energy, we don't want to eat much hot food.  We eat salads and sandwiches and cold snacks.    We're dreaming of ice cubes. 

Right now, I can make ice cubes in the cockpit, but, of course, nobody wants ice cubes.  Both of us want tea and soup for every meal, but the sun is so low and the days are so short I doubt we could significantly heat up water in with the sun.

If we could only learn to eat soup in July and ice cream in January, we'd save a bundle on propane and ice. 

[Owly055]

It's cool that people are actually doing this...........