Tuesday, February 19, 2008

Budget Survival – Cheap Water Heating

When I first decided to build at Bear Ridge the one thing that I could not do without was a hot tub. There is nothing better than sitting in steaming water under an open canopy of stars. It was something I had to have. The two problems were lack of water and a method to heat it. Capturing rain provided plenty of water but heating it was slightly more involved.

Passive Solar

When I first started making the trips down there I would carry water in blue seven gallon plastic jugs. If I needed a shower the jug would be placed in the sun all day and by evening the water would be a comfortable temperature. I would take the jug into the bathroom, drop the water pump feeder hose for the into the top and shower. Real simple…cost nothing.

The main problem with using this solar heating method was that you had to have good sun. If it was cloudy no go, and forget about taking a shower in the morning or in the winter.

This summer I plan on taking an old refrigerator, removing the door and with a glass cover using this as a water heater for showering and such. The insulated refrigerator should keep the water warm throughout the night.

Propane Water Heater

I set out to build an efficient off grid water heating system that could be used to heat the hot tub or water for showering and dishes. The heater needed to warm the water quickly and be easily transported. This is what I came up with.

I took twenty feet of 3/8 inch copper pipe (HomeDepot $40) and rolled it around an old coffee can leaving a foot sticking out at the top and bottom, this is my heating coil. I then attached eight foot of garden hose to both ends of the copper with hose clamps. The bottom inbound hose is attached with hose clamps to a 12 volt bilge pump (Walmart $10). The top outbound hose needs a flow control valve (HomeDepot $10) attached to its end.

Get a turkey fryer, everyone has an old one of these laying around in the garage (new one run about $40). A gas grill will not work. Gas grills produce around 9000 BTU and that is not nearly enough, turkey fryers can generate 120000 BTU. You also need a twenty pound bottle of propane.

Place your heating coil over the burner so the heat is directed up through the center. Stack bricks around three sides of your coil then place a paver over the top. The side with the inbound and outbound hoses should be left open. Stack the bricks as close to the coil as possible.

Fully open the flow control and drop the bilge pump and outbound hose in the water tank. My water tank is a one hundred gallon stock tank and being that I am a chunky bitch I only need about 50 gallons of water to comfortably soak. Plug the bilge pump into the 12 volt power source and get the water flowing.

Once the water is moving light the turkey fryer. The water leaving output hose 30 to 40 degrees hotter than the water sitting in the tank. You should reduce the flow as much as possible, the longer the water is in the heat the warmer it gets. The bilge pump being used moves 450 gallons per hour not a lot but it is really efficient. My hot tub can be warmed to over 110 degrees in under an hour and the entire system can be carried by hand.

Do not use this heater indoors, it will kill you.

The next time I do this I will use forty feet of 1/4 inch copper tubing.

I was going to include a picture but the thing is in the backyard under about three feet of snow and I couldn't exactly remember where I put it.

Wood Heater

The next project is a wood burning heater based on the same principle with a copper tube lining a round barrel. Trash and scrap lumber can be utilized to bring the water to a nice temperature.

6 comments:

Anonymous said...

Bigbear,

Have a look at
http://www.cowboyhottubs.com/

They make a wood heater that fits in the hot tub.
A 5 gal bucket of split wood will do the job.

I plan on doing a hut tub when I move to SDCR hopefully in a small yurt.

Ryan said...

FF said it well. I have seen kits and adds for that sort of thing in outdoor magazines. Could be some plans online here or there.

Dragon said...

another water heating solution would be to tear apart a drip coffee maker to see how it works. Then super size it to work with your wood fire or rocket heater...Dragon

BigBear said...

dragon,

I actually tested heating the water with an old coffee maker. I got a spiphon going into the water tank on the coffee maker then attached a small hose to the hotwater making output thing. It did heat the water but took forever and would cost a fortune.

Anonymous said...

Your gas fired water heater will work just fine without the circulation pump or the restriction valve. Our hunting camp is quipeed with an antique version of this.

The glass door on the solar heater will let heat radiate back to the night sky. Plan on putting an insulated cover over the glass at night.

elisag said...

hey Bear... many years ago I saw an article about making a roof or tower mounted water heater using a 50 gal drum painted black...hope I can find that article again...