Solar water heat exchanger
- Thread starter gettinthere
- Start date
Specificity also helps. You first said boat, then said "whole house" then later took me to task because you didn't define whole house, which I took literally, i.e. house, gee, sorry for that. You get almost immediate help from Jim with a total system diagram he found, and then claim you can't find stuff. I suggest: you keep looking. I also refer you to my first post: I have been active on sailing forums since the internet started and have owned boats since 1983. Boat solar systems for your initial request are rare. Could be why you're not finding any? Good luck hunting.
The expansion/accumulator tank is plumbed upstream of the hot water. I don't see any difference between using the engine to heat the water VS solar as the OP suggested.
Expansion and Accumulator tanks are different beasts. Most (all?) engine cooling systems have an expansion tank into which the heated water expands into to reduce the pressure in the cooling system from the expanded water.
An expansion tank reduces the pressure in the cooling system due to the expansion of heated water. An accumulator tank maintains the pressure in the freshwater system to reduce pump cycling.
Ah. I thought you meant he needed an expansion tank on the fresh water side. His heating "coolant" wouldn't need to be pressurized or sealed like an engine.
That depends on a couple of factors, the pressure from the circulation pump and how hot the water in the solar collector gets. If the collector only heats the heating fluid to a fairly low temp, like 120° it can probably skip the expansion tank, but if it gets up close to that of a diesel, say 160°+, a tank may be needed.
Off-topic, but to answer your question mark - not all. We had a Universal M12 on an O’Day 28 with no expansion tank, only the main reservoir. Not sure exactly how that worked but it never caused us a problem.
This system isn't storing the hot water. Your intentions are to transfer the heat to heat the water in the tank. For how long and to what end?
It seems like a Rube Goldberg approach to bathe or clean dishes.
We have lived aboard for 5 years. During the COVID time we eschewed the marina facilities, including showering on board. We found that 6 gallons of warm water can go a long way. If you heat it up the night before you have non cold water all of the next day.
My experiences with solar heating water have been very positive, including in Alaska with the plastic bag type solar showers. The original posters idea seems quite feasible to me based on my experience, and understanding of heat and mass transfer. It is simple and inexpensive and connects easily to the existing tank. It has basically the right proportions to work.
I say go for it and let us know how it turned out.