Off Grid Well Pump and shower house input

[jeetS]

Hi, I'm helping a family member out with a project and would love some input and advise.



He has some off grid property and wants to put in a well and will build an insulated 8x8 pump house with a pressure tank and would like to be able to use it year round.
The roof will be larger to ensure enough space for the solar panels and to provide some dry storage underneath.

In the winter it can get down to -20c and would likely be used for 4-8 days a month in the winter.
3.4 annual average peak sun hours

The pressure tank would be drained when not in use during the winter and the shed will freeze as I cannot imagine a sensible/affordable way to keep it heated for weeks at a time with nobody there unless you leave a propane furnace on the entire time (assuming solar heat would require a truck load of batteries and solar panels, which doesn't seem practical or affordable!)

I know that once the well is drilled that will determine pump size and then also inverter size for a starting point.

My current thoughts are to install an RV furnace running on propane so when someone is there in the winter they can turn the furnace on, turn the pump on to fill the pressure tank and use the water for those few days. Would also have a small outdoor on demand hot water shower and some hose bibs for drinking water or to wash mud/dirt off people and equipment.

He would also love to use this building as a hub to bring a 15a circuit to some cabins/rv pads in the areas but maybe the cable requirements would make it more logical to just have independent solar setups at these locations.

I have some past minor experience with RV solar setups but would love any advise or input.


Default starting point would be some golf cart lead acid batteries with a MPPT charge controller so we can have some panels in series to ensure were getting enough voltage in the winter months. I think with the cold temps lead acid would be the way to go?

 

[DThames]

You might consider an insulated pit under the building like a partial basement. Surrounded by earth and down some number of feet, it should not get above freezing if the top was well insulated. If I were doing that, I would make sure the well casing was exposed inside the pit. The inside of the well will be warm. Warm air will rise to the top, where your cooler pit is. Some amount of heat will be lost to the pit room. It very well may be enough to keep the pit above freezing. If so, good home for batteries and piping.

 

[MichaelK]

Lots of decisions here to make. You can go with either DC or AC, 120V or 240V. In my own case, I've built a room over my well to protect it from freezing, though I'm not seeing -20 weather like you do. To my knowledge the winter has never dipped below zero at my location. I used to drain the system every winter until I built the room. Now I have 12month water.

A good rule of thumb is that for whatever application you have, you need 2X the amount of panels to run what your load requires. My pump requires 2200W to run, so I installed 4500W of panels.

So, the wildcards here are what kind of pump you are going to need to get the amount of water you want. Depending on the pump, golf-carts might or might not be acceptable. Assuming you don't want to put a load on the GC more than 1/8th of C, and C is 210Ah, that's
210Ah/8 X 48V = 1260W. That would accomodate a 1/2hp pump OK. If it's determined that you need a 1hp pump, then you'll need to upgrade your plans.

 

[rhino]

Please look at a 120V version of a Grundfos pump. They are highly efficient, soft start, and don't require 240V AC like so many other well pumps normally sold to people.

 

[jeetS]

Please look at a 120V version of a Grundfos pump. They are highly efficient, soft start, and don't require 240V AC like so many other well pumps normally sold to people.

Ok thanks I will.

 

[jeetS]

Thanks for the input here. A partial basement is an interesting idea, however I think he is planning on having the pumphouse not directly over the well.
He will be meeting with the drilling company soon so should have more firm plans.

 

[MichaelK]

I designed my utility room to go over the well to make it 12 month secure. So, no more winterizing/draining pipes. I designed a hatch in the roof so when the pump finally fails some day, it can still be pulled out. I just need to unscrew the roofing panels covering it, unscrewing the plywood, and then I have a 3'X3' access port.

 

[jeetS]

I designed my utility room to go over the well to make it 12 month secure. So, no more winterizing/draining pipes. I designed a hatch in the roof so when the pump finally fails some day, it can still be pulled out. I just need to unscrew the roofing panels covering it, unscrewing the plywood, and then I have a 3'X3' access port.

Is your utility room off grid? How do you keep it above freezing?

 

[MichaelK]

Is your utility room off grid? How do you keep it above freezing?

The entire homestead is off-grid. All the water piping except in the orchard is underground, so is protected. Pipes at the well-head were unprotected before I built the utility room, and they had to be drained in winter. The single most frost sensitive part was the water meter. Two failed before I finally completely disconnected it and brought it into the cabin.

All that has changed now that the 12X12 room is built over the well-head. It drops into the teens in winter, and we get snow, but the room is insulated enough that it stays above freezing even without supplemental heat. Maybe if I was further up the mountain I would need heat. The irrigation pipe is the only thing that is still unprotected, and I have to drain that ~the first week of November.

At 5000', if I keep the water tanks full, they will not freeze, even though they are fully exposed to the weather. The previous owner, when I bought the property, warned me never to let the tank sit empty in winter. Then there would not be enough mass to keep the tanks above freezing.

 

[Vigilant24]

Thanks for the input here. A partial basement is an interesting idea, however I think he is planning on having the pumphouse not directly over the well.
He will be meeting with the drilling company soon so should have more firm plans.

If the pumphouse can have a pit that goes down below the local frost line (same depth that the pitless adapter will leave the well, and that the underground water lines will be buried), then the pressure tank, pressure switch, etc can go in that pit. Put a very well insulated and tight fitting cover over that and it will never freeze. If it DOES freeze, all your underground lines will also have frozen and you'll conceivably have big problems anyway.

Honestly, you don't need a true "pumphouse" at all, just the pit and a cover over it that will shed rainwater somewhere other than into the pit (or near enough that it would seep in).

It is NOT a good idea to put this pit at the wellhead. That's the way old "pit" wells are constructed, and if they gather nearby water it can get ful of microbes and contaminate the well itself.

Now, one "gotcha" is the need to assure the pit doesn't fill up with water (from outside drainage nearby, off any pumproom roof, etc). Also, that pit will need to be big enough to allow servicing of the components (replacing the pressure tank, etc). But, there's no need for a heater of any kind, just as there's no need to heat the other buried lines coming from the well. The heat in the deeper ground will do the trick. But insulate the lid over the pit or it will freeze up in there.