Can't find my pencil-and-paper sketch right now - which is how I do anything unless I'm going full computer. So I'll try the written version. 😏What sort of filtration are you planning on for the recirc shower? Seems like a combo of the 5 micron 10" carbon cartridge filter plus a UV light would do the trick but we'll see. And are you going to be running the filtered water back through your hot water heater or how do you plan to keep it warm? I have a surecal calorifier (aka hot water heater that uses engine coolant to heat the hot water) so I'm thinking of running the shower water through a multi-plate heat exchanger that's also hooked into the calorifier's coolant loop to warm the water but the devil's in the details as I'd like to be able to just maintain a certain shower water temp so I'd have to have a couple of temp sensors and some 'smarts' to control the coolant pump to try to maintain that temp. The other option is to just have a 1 or 2 gallon hot water heater dedicated to the shower and just have it set to maintain the temp you want...
Still thinking about this one 🤣
I looked at a LOT of designs - from really complex, fully automatic to fully manual with one mixer for fresh and another for recirc. Even dug into a few of the Euro house designs - as well as some very simple RV setups. I decided to keep it simple-ish. Ideally, it will just work as a non-recirc - which is all we had in the past, so that seems good.
We've got 18 gallons of fresh water inside the rig and another 20 gallons under the rig. And a 4-gallon Bosch water heater. Primary feed to the shower is straight from the internal fresh hot and cold - already plumbed and ready for me to get working. With the Bosch at ~140F, should be a 50/50 or less - so an 8-gallon shower is possible for starters. But hoping to get better with recirc.
Two "drain" systems:
1. drains down to the gray-water tank - both from the drain and from an over-flow;
2. pumps the drain water through filters then up to a mixer then to the shower head.
Two "supply" systems:
1. standard hot and cold mixer - feed side feeds into second mixer;
2. second mixer combines fresh hot/cold with recirculated, filtered.
Plan is to only use recirc to lengthen one shower - not to scrub the water for multiple showers. So hoping to do it with a minimum of filters. Currently have one small basic filter (can't recall size) then a large 100-micron easy-clean filter then going to a high-flow 0.5-micron disposable filter. Hoping that will be enough to keep one shower going for a while by just adding some hot water now and then. Might add another 50-micron or smaller easy-clean if we clog the big one too fast.
Current plan is just to use the bottom of the shower basin (with a wood grate over it) as the recirculated water supply. I haven't tested this yet, though. If that's not enough, then I'll need to convert the gray-water tank into a recirc storage tank and things get more complicated - especially for the removable bit. Hoping the current plan will work.
So a shower would involve switching the drain valve to recirc, then starting with standard hot/cold mixer until there's enough water in the basin, then engaging the recirc pump. Then using the second mixer to determine how much water from recirc and how much from fresh. I'm thinking if I can get a 10-minute shower with only 3-4 gallons of water, that'd be fantastic.
It's partially assembled... but zero testing yet. I keep rethinking things and moving back to other projects. It'll progress eventually... 🤔