# The universal water preheater



## Boris (Nov 18, 2010)

The design of my universal water preheater is very simple and realistic:
Two hundred feet of orange 5/8" PEX , as a heat exchanger, was installed into the blue 55-gallon plastic barrel. 
This heat exchanger is connected to the solar collector and filled with antifreeze. 
The plastic barrel filled with chlorinated water.
I also installed two hundred feet of white 3/4" Sharkbite PEX in the same barrel and connected this coil to my electric water heater. I prefer the Sharkbite PEX, because it's compatible with SharkBite push-fit fittings or barbed fittings and recommended for residential and commercial plumbing applications, including water-supply systems.
The 12V DC circulator is powered by 10W solar panel.
Note: the lower valve (located between two tees) is closed.










More details are posted here:
https://sites.google.com/site/solarwaterpreheater/

Boris Romanov


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## Ky-Jeeper (Sep 5, 2010)

Thanks Boris


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## Boris (Nov 18, 2010)

Ky-Jeeper said:


> Thanks Boris


You're welcome.

I would recommend to use the *Open-Head/Lid * drums to easy installation of Sharkbite PEX.

In my opinion the Open-Head Plastic 55 gal Drum ("B") just for $51.70 is the real bargain:









*Product Description:*
Open-Head Plastic 55 gal Drums are perfect for storing a wide variety of solid material from chemicals to food. *Constructed of blow-molded, high-density polyethylene that will not rust or corrode.* Crack-resistant walls are 0.125" thick. Removable polyethylene lid includes metal locking ring and a Buna-N gasket. UN-approved. Materials have been approved for FDA standards. Color: blue.
*NOTE:* For use with water based solutions, acids and corrosives, food, detergents, waxes, disinfectants, kerosene, or light oils. Style B in image depicts product.
From: http://www.amazon.com/gp/product/B0...IN=B002SVZ4XM&linkCode=as2&tag=beebehavior-20

The metal drums are preferable, if you are going to install your water preheater near your wood stove:








From:http://www.amazon.com/gp/product/B0...IN=B006P5RR8C&linkCode=as2&tag=beebehavior-20

Boris Romanov
www.borisromanov.com


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## 12vman (Feb 17, 2004)

I've suggested using a standard h/w tank with the outside covering/insulation removed and running the main water supply through it before it enters the working tank. This would collect the ambient room temperature and take a lot of the chill from the water before it gets heated. It might sweat a little but it would be worth it.. (Basement/room dehumidifier?)

A stripped gas h/w tank would actually work a little better, being it has the tube up the middle, which would allow more air from the room to circulate around it. (more surface to the surrounding air) Perhaps adding a small fan to push air through the center tube would help..


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## Boris (Nov 18, 2010)

12vman said:


> I've suggested using a standard h/w tank with the outside covering/insulation removed and running the main water supply through it before it enters the working tank...


Based on my personal experience, normally used electric/gas tanks are in a bad shape and without insulation and metal skin/shell they cannot keep pressure. 
But if you have a welding machine/apparatus - you can fix it, like I did it many times:









Unfortunately, they will start to leak again at any unpredictable place and time.

If you do not want to install a heat exchanger, to make your water preheater universal, I would recommend to buy a galvanized/steel water tank, that can keep water under pressure: http://www.tractorsupply.com/countyline-reg-galvanized-tank-vertical-42-gal-capacity-3123360

Boris Romanov/


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## 12vman (Feb 17, 2004)

I agree.. Those buggers will start to leak when you least expect it..

I figure the heat and cold water is what makes them fail. I'm not sure if the inside of the newer tanks are glass lined like they used to be. If so, a new damaged one would be nice to find. The chances of the glass liner being damaged would be low. (Thinkin' scratch and dent) I believe the bare tank itself would handle the pressure if it wasn't used and somewhat rusted out..


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## LadyHawk77 (Oct 11, 2011)

Why did you need to have the plastic barrel filled with chlorinated water? Do you have to replace the water or check levels of chlorination from time to time?


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## 12vman (Feb 17, 2004)

In Boris's design, he's using the 55 gal. drum as a reservoir, using water as a heat exchanger between the coiled PEX pipe inside of the 55 gal. drum and the heated water from his heat collector, outside of the house. (a coiled pipe in a bath of heated water)

The water in the drum is circulated from the drum, using the small pump on top of the drum, moving it to the outside heat collector, and back to the drum. It just free flows.. Through the pump, to the heat collector, and back to the drum. The water gets pumped through the collector, gets heated, returns to the drum and gets pumped back through the system over and over again. This water never mixes with the home water supply. It's basically a closed system, seperate from the house supply.

The reason for the chlorine is to keep the water that's being pumped through the system from getting skanky or stagnant. Don't want any algae growing in there, which it would without the chlorine. 

The amount of chlorine/water in the drum has no effect on the house water, being both are seperate from each other. The house water simply flows through the coiled PEX pipe, collects heat from the heated water in the drum and goes to the h/w tank.

I imagine the water in the drum need attention from time to time because of evaporation. (just top it off when it needs it) A touch of chlorine now and then just to keep the nasties from growing..


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## Boris (Nov 18, 2010)

12vman,

Thank you for your reply.

Some remarks. 
As I stated previously: "Two hundred feet of orange 5/8" PEX , as a heat exchanger, was installed into the blue 55-gallon plastic barrel. This heat exchanger is connected to the solar collector and filled with antifreeze."

My worry free design is for cold climate, therefore I prefer to use antifreeze in all my solar collectors.
So, this heat exchanger (or warm surrounding air) heats water in the barrel. 
The circulator/pump circulates antifreeze, but not water in the barrel.

The second heat exchanger (white PEX) accepts this heat.

In short about chlorination: to prevent smell of water (bacterial growth) I prefer to add about 16 Oz. of Clorox into my barrel with 55 gallons of water.

Boris Romanov


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## 12vman (Feb 17, 2004)

Do you have 2 coils in there? Sorry.. I missed that. I bet it was fun getting all of that Pex coiled through the bungs. Now I understand the open top barrels that you suggest.

I apologize for running my keys without totally understanding your system and answering a comment directed to you. Guess I wasn't thinkin'..


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## Boris (Nov 18, 2010)

12vman said:


> Do you have 2 coils in there?..


Yes. Two coils are installed in the barrel.


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## 12vman (Feb 17, 2004)

How good is the heat transfer? How long have you been using it?


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## Boris (Nov 18, 2010)

12vman said:


> How good is the heat transfer?...


In general, copper for *water to water* heat exchangers is better than PEX, but copper is too expansive now. 
For example, 3/4" x 100' Type L Copper Tubing Coil - $584.95 (http://www.pexsupply.com/Wieland-34L100-3-4-x-100-Type-L-Copper-Tubing-Coil-11158000-p)










Nevertheless, I tried to reduce the initial cost of main components for my water preheater: free plastic barrel, free heating elements (used) for my solar collector and bargain price for the PEX &#8211;  I bought a three hundred foot of coil of 5/8&#8221; PEX just for $57.
Therefore the payback period for my water preheater was about 2 years.

I would recommend you to make your own calculation, based on your specific situation (cost of materials, location of your water preheater and so on). 
But if you will not be satisfied with your payback period &#8211; try to consider about spending your money for a modern energy efficient water heater, especially in situation, when some modern water heaters are 99.8 percent Energy efficient!
More details are posted here: Solar water heaters

Boris Romanov

P.S.
Water to Water Heat Exchangers: http://www.iqsdirectory.com/water-to-water-heat-exchangers/


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## GregYohn (Jan 24, 2013)

Put 100ft of pex tubing in the concrete roof in Cali, Colombia. Get hot showers with SharkBite attached to CPVC and pex. Idea could be used in the USA, but drained when outside temps get below ground water temperature. Mine was just passive and used no pumps.


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