(Aug 2) Closed-Loop Shower System

I've had a lot of interest and questions about our closed loop shower system. I finally took a quick picture to show the components. It's really pretty simple. 

The Flojet pump  is hooked to a couple of 12v batteries. It doesn't take that many, that's just what I have on hand out there and by keeping them tied together, they both stay charged. The charger is wired to a switch inside the house so that I can turn it off if needed without unplugging it. (We're planning on upgrading this to a solar panel with charge controller/inverter this fall.) The pump has a draw side that's hooked to a water hose that's seated in a 5 gallon water jug that's had the top cut off. The output side of the pump sends the water through a filter (just sediment at this point since we're bringing our water from a city source) and then into the L10 tankless heater from Eccotemp. From here the Pex line goes into the house and to the shower head. I have a ball valve on the shower head that's used to start the flow. When the pump senses the water pressure drop, it kicks on automatically. As soon as you close the valve, the pump shuts off - very quick and self-priming. The water that drains out of the shower, goes right back into the water jug under the house, thus the closed-loop. The system acts just like city water. I did have to purchase additional adapters to tie my pump inputs to a standard garden hose. They make a variety of quick connect adapters for 1/2", 3/4" and garden hose in both straight and elbow versions to make it easy to adapt to whatever you have. 

For now, while the weather's warm, we heat our water in 5 gallon jugs in the sun. One jug per shower, thank you! A couple of hours brings it up to 110° which is plenty hot enough to take a 15-20 min shower depending on how cold we have the house at the time. We tend to keep the thermostat set at 65° to 67° in the summer just because we can! :)

When we need to use the heater, I just open the valve on the propane and the heater unit turns on automatically when it senses water flow. It takes (4) D size batteries for ignition. I will say that you need pretty good pressure to get it to come on reliably. We ended up swapping out our first pump which didn't provide enough pressure and didn't have a pressure switch built in. This one is a Flojet rated at 50 psi for and 2.8 gallons per minute flow. Plenty of pressure and plenty of water. Since it's feeding the water that it's heating right back into a loop, the temperature rises quickly in the storage tank. We typically heat the water 4-5 minutes, again to hot-tub temps, and then shut it off and start our showers. I haven't played with it enough to find a setting that's low enough to have it maintain a constant "very warm" temperature and I typically don't take showers that are longer than 20 minutes anyway. At 4-5 min per shower, a 20lb tank of propane should last us 6-8 months. 

When we're done with a shower, I just dump the water out by a tree and refill it if someone else is to take a shower. If we're staying for multiple days, I run a bit of fresh water through to flush the system. I also pull the filter and let it air dry when we leave for the week. It does OK when we're there taking showers daily but tends to sour a bit when it sits for a week or two without use. We accidentally put one of the water filter cartridges in the wash with our laundry one night. It came out amazingly clean and worked like a champ the next time. Now, we wash them regularly (monthly) to keep 'em fresh. 

Shower system. R to L - water storage and return pipe from shower, pump, batteries & charger, filter, heater & propane.

Closed-Loop shower system diagram

When I build the closet around all of the above, I'll add the bypass and extra valves shown in the diagram that aren't in place as of yet. We'll also have a large propane tank (250 gallon) in place by that time and have it plumbed into the heater and the kitchen range/stove. I keep thinking I need to get something fancier than a water jug for the storage tank but I can't think of anything that will work better and be cheaper. Sometimes you just have to accept the the best solution is the simplest, no matter how plain. :)  We'll also plumb a line from the cistern so that we can fill directly from it when we want. I suspect we will still use the jugs for the most part as they're easy to set in the sun and get heated for free. 

I would also love to put a solar water heater on the roof of the house that would drain straight down to the holding tank and to the kitchen. Maybe a project to take on once we finish construction of the house. Seems a terrible waste of fuel to heat water for cooking or bathing when it's 100° outside for most of the summer. Just like our relatives in Maine that take advantage of the cold in the winter and use a shelf in their garage as freezer overflow, we should look to take advantage of the abundance of heat we have here in the South. :)