Community Forums

nothermark · 10-27-2017, 11:22 AM

I'd route the solar output into the water heater input so the water heater topped off the solar heated water. If there was 5 gallons or so of hot water in the solar that should keep the burner from coming on. The solar would get used first so could reheat if all one used was what was stored in the solar heater. If not you are looking at a cold shower or running gas anyway. As was mentioned, it would work better after the sun was out for a while.

Whatever I did I would put in cutoffs and drains so I could empty the system in cool weather. I'd be worried about insufficient heating or freezing the solar heater when the rest of the system was fine.

cruzbill · 10-27-2017, 11:58 AM

Home solar HWH use a recirculation pump to distribute the heated water to the storage tank, the hot water won't 'move' there by itself. Of course, the solar HWH works in reverse at night, it will try and remove all that stored heat and will 'dump' it to the night sky (infinite heat sink). So now you're talking more controls.....

okmunky · 10-27-2017, 01:29 PM

I've considered both of the ideas above. Nothermark's plan to let the propane water heater assist is of course the easiest, but Cruzbill's suggestion intrigues me.

I'm assuming that to recirculate the water would only require a T after the the onboard water heater output that sends a line back to the solar input and a small 12v water pump. If the max height the pump needs to push water above the onboard water pump is 24 inches, what would be the smallest pump rating (gallons/minute) I should consider? I would think the water flow needs to be slow to allow for sufficient heating.

okcnewbie · 10-27-2017, 01:37 PM

I can't get past the math.....

Cost about $3 dollar to go 7 miles.
Way less than a dollar for 15 minutes to heat more water than I use to take a shower. I guess if someone is just going to park in the woods and try and live off the grid it could work?

LoveToGlamp · 10-27-2017, 03:27 PM

okcnewbie, I agree. I can go a week on less than $12 of propane, using water heater, stove, and fridge. Makes no sense to me to bypass a perfectly-good water heating system, just to spend time and money to do it differently.

If you want to use more water and less propane, where is the water coming from? You have a finite amount in the Fresh tank. If you have to go somewhere to refill the Fresh tank, you may as well refill propane (or carry a spare. We have two cylinders on our tongue, with room for one more).

cruzbill · 10-27-2017, 03:31 PM

On-demand HWH regulate flow using temperature feedback. Now you need a temp controller with a variable voltage output........It gets complicated in a hurry. Not to say that it can't be done.......

nothermark · 10-27-2017, 03:47 PM

If somebody is long terming in warm to hot places adding something like 50 ft of black tubing and some fittings would have a fairly fast payback. That was what I was thinking with my first message. A lot of those folks have ways other than moving the RV to handle water and waste. They have built in tanks so it would take an extend a stay setup to use replaceable tanks.

okmunky · 10-27-2017, 07:25 PM

I'm prepping for 4-5 months at Quartzsite. I have an extend-a-stay, 2 20# propane tanks, water and dump barrels and a way to transport them to the water and dump stations in La Posa South.

Solar water heating is more about making the science work than about the cost of propane. I'd like to prove that workable solar water heating in an RV can be done for less than $50 in parts. DIY stuff keeps my body and brain cells from deteriorating

I'm not looking for an install and forget it system like you'd have in a sticks and bricks, but for a decent shower - even if it has to be in the afternoon and I turn it on and off as needed.

okmunky · 10-27-2017, 09:30 PM

Also, I’ve seen a bypass valve that would allow the cold water in the hot water lines to be returned to the fresh water tank rather than going down the drain wasted and filling the gray tank.

If the onboard pump can handle 100’ of black tubing that would allow 10 gallons of solar heated water to go into the water heater tank. I've taken a decent shower with 6 gallons of propane heated water and an Oxegenics shower head.

1bigmess · 10-27-2017, 10:15 PM

My hot water heater holds six gallons. I can take a shower using less than that and still have hot water left over to shave. If you live in an RV and haven't learned to use less than six gallons of hot water to get cleaned up, in my not at all humble opinion, you're wasting water and the energy to make it.

okmunky · 10-28-2017, 12:59 AM

I shower with a monkey on my shoulders. We can do it in 6, but I'd enjoy the luxury of a bit more. We still use less than taking separate showers

nothermark · 10-28-2017, 06:57 AM

Quote:

Originally Posted by okmunky

I'm prepping for 4-5 months at Quartzsite. I have an extend-a-stay, 2 20# propane tanks, water and dump barrels and a way to transport them to the water and dump stations in La Posa South.

Solar water heating is more about making the science work than about the cost of propane. I'd like to prove that workable solar water heating in an RV can be done for less than $50 in parts. DIY stuff keeps my body and brain cells from deteriorating

I'm not looking for an install and forget it system like you'd have in a sticks and bricks, but for a decent shower - even if it has to be in the afternoon and I turn it on and off as needed.

In a setup like that I might think outside shower with a direct tap off the tubing and a cold water line to temper what came out of that. Could do a solid enough shelter to protect the innocent and get a clean floor to stand on. Very little waste while the water got to the shower head as the tubing would be right there. Thinking about it some T's, tubing, and separate valve to the outside shower handle would probably do the trick. Choice of solar, hot, or cold into the place where the shower handle attaches to the RV. Take off that run of tubing and plug the hole at the take off when breaking down for travel. Not something to do for an overnight but well within setup and take down for months on site. ;-)

okmunky · 10-28-2017, 08:08 AM

I don’t think the BLM would allow even shower water to be dumped on the ground, but I'll check. That would certainly work for many boondocking locations. Thanks!

1bigmess · 10-28-2017, 10:30 AM

Rules for dumping gray water on the ground can be site specific, so check with the agency or property owner where you wish to do it at each location. I've been given the OK in some places, and told no in others.

When I've been told it was OK, I was told that if the water has gone into my tanks then it's not ok. It is not OK to dump the gray water out of my tanks. Gotta capture it in a basin and dump it outside, or do the work outside. That makes it sound like an outside shower would be OK.

Try to find a good pallet to use as the shower floor on the way down.