Re: Poor man's solar water heater

Interesting, is the cold water from mains supply ... is there a big pressure difference between cold supply and the gravity-fed hot supply?

If so, to shower, I assume you completely shut off the cold (via the shower valve) and turn on the hot instead of allowing 'mixing' at the T joint in the bottom picture?

Re: Poor man's solar water heater

Interesting, is the cold water from mains supply ... is there a big pressure difference between cold supply and the gravity-fed hot supply?

If so, to shower, I assume you completely shut off the cold (via the shower valve) and turn on the hot instead of allowing 'mixing' at the T joint in the bottom picture?

Yes cold water comes from the shower valve while the submersible pump is off. I manually top up in the evening.

When I want warm water, I turn on the submersible pump which forces down the warm water. Since this setup has no temperature regulation on the reservoir side. I manually mix the right temperature by fiddling withe the shower valve versus the valve coming in from the hot water reservoir.

During partly cloudy days, I usually don't need to mix.

My previous version had the hot line isolated and did not require the power of the submersible pump. Nowadays, since the "telephone" shower has a small internal diameter hose, and the higher cold water pressure, hot water pressure is needed.

Re: Poor man's solar water heater

Sir, this innovation is inspiring and I am thinking of making one. I am contemplating on using
copper tubes embedded in tar in roof and perhaps oil as medium of heat transfer. I do not
know if this is feasible.....

Re: Poor man's solar water heater

@VivaFoxpro,

Been following this thread and yes your little creation is indeed a very useful and effective one. Sure this will save you lots of pesos on your electric bill so keep it up brad, maybe this small experiment of yours will end up into something bigger.

Like the pics you posted but not the videos you made, the videos did not explain anything for me to simply follow or understand. Bro no offense here ha ! Like I said I like your idea there on the little creation, there is a big potential in the experiment.

Thanks for sharing this to the forum bro. !!! :thanks: 😉

Re: Poor man's solar water heater

Sir, this innovation is inspiring and I am thinking of making one. I am contemplating on using
copper tubes embedded in tar in roof and perhaps oil as medium of heat transfer. I do not
know if this is feasible.....

Feasibility like anything else is relative. If in your locality and your skill set, copper tubing, tar and oil is readily available and affordable, then go for it.

It turns out, in my solution, the components used were the ones easily available.

I will post a more detailed guide below Sir.

Re: Poor man's solar water heater

@Larry & @Rosy,

I held back on the details in case no one got interested, thus saving some effort. Now that the contrary is true, bear with me as I go through the project.

Necessity is the mother of invention, as the saying goes... My own particular case is I work till 2 or 3AM and prefer to shower just before plopping down to bed. Cold weather makes this a bit difficult.

Add to that, I find a warm shower relaxing and luxurious.

I almost bought those water heaters you attach directly to the shower. They cost from 4 thou upwards. The deal broke when they showed me the internals of the device. Nothing but a heater and a thermostat. Knowing how both of these work, somehow at the back of my mind, they were charging way too much. Secondly, they wanted to do visit my house to install it. Extra hassle.

I ended up buying the water heater you dip into a pail of water and then wait for it to warm up. Using the "tabo" procedure, pwede na rin. Kaya lang malakas sa koryente to.

I remember long time ago when my mother wanted a warm shower, she had me put out a pail of water out in the sun and lo and behold - free warm water for her.

Katulad din ninyo, Google is our best friend and I did some research on various ways solar water heating is implemented.

So here goes:

The main requirements I posed to myself were:

1. Heating element - I saw one solution where a black hose was used to absorb heat. Luckily I found some in Ace Hardware used for drip irrigation. Im sure ordinary garden hose will also work for this. I found out that this solution does not obey the "thermal siphon" principle that acts on more expensive solar water heating. I had to mechanically circulate the cold water from the reservoir to the heat collectors. Version 1 was I had the reservoir (a "coleman" type insulated ice box or cooler. I will refer to it as cooler in this pos) at ground level and the heat collectors on top of my kitchen roof. I used a pump for 20 minutes and got moderately warm water in the evening. I manually diverted the hoses everyday when I did the warming first sending the flow to the roof, then connect the pump so that it will send the collected warm water to the shower. I connected the motor to the bathroom's light so that I can control it at the time I needed the warm water. This was an improvement on electric consumption of the "dip type" water heater. The pump was about 30watts vs 1600watts for the heater.

Later on I brought up the cooler on top of the kitchen roof beside the black hose, bought a CDR King solar panel and those CDR King"tranquility fountain" to circulate the water around. Each motor lasted about 2 weeks only and since the fountains were on sale for P150, I bought 5 pcs as reserve. Dahil nga marupok sila, I started thinking for another way to circulate the water.

Long time ago, I understood that aquarium aerators not only gave oxygen to fish but also moved water down into the sand which acted as a filter. Presently, that is how I drive the water - via air bubbles produced by the aquarium aerator mechanism driven by another CDR King usb fan motor. I achieve vibration by putting an off center lead weight (silver tape covered in my video)

All these driver by solar power.

2. Reservoir - I needed the warm water at 2AM so an insulated container is a must. The cooler is the best solution so far. It is not pressurized. Gravity does the job of getting the water from kitchen roof level to the first floor shower. Initially it was this simple pero some days sobrang init yung tubig I have to put in a pail and add some cold water. Back to "tabo" technique. To fill up the cooler with cold water I have a hose from the garden faucet.

3. Delivery system - the present version makes use of the pump again to overcome the pressure of the cold water line. I employ 3 valves - one for warm, one for cold and the third to shut off the "mixed" output to the shower. During use I turn on pump, open valve 3 and mix cold and hot water using combination of valve 1 & 2. After showering, turn off pump, close valve 3 and fully open valve 1 & 2 - this allows cold filtered water to go up to the cooler. Once the cooler overflows, turn off valves 1 & 2 and open valve 3.

Presently I have again saved electricity from 20 minutes running time of the pump for heating plus another 5 during shower. I plan to get rid of the pump eventually and rely purely on gravity.

I hope this post will help you in your own use of the virtually infinite source of power that is the sun.

Parang sobra nga yung output power nung solar panel at feeling ko pwede sya lagyan ng rechargeable battery to utilize as light at night or usb fans for cooling this summer months.

Either way, I hope to make another post kung matuloy man sya.

Re: Poor man's solar water heater

When I want warm water, I turn on the submersible pump which forces down the warm water. Since this setup has no temperature regulation on the reservoir side. I manually mix the right temperature by fiddling withe the shower valve versus the valve coming in from the hot water reservoir.

My previous version had the hot line isolated and did not require the power of the submersible pump. Nowadays, since the "telephone" shower has a small internal diameter hose, and the higher cold water pressure, hot water pressure is needed.

3. Delivery system - the present version makes use of the pump again to overcome the pressure of the cold water line.

I plan to get rid of the pump eventually and rely purely on gravity.

Had similar issues related to cold vs. hot pressure difference with our solar water heater which is a roof-mounted, cheaper open-type (as opposed to closed/pressurized), with gravity-fed output.

In the first few years of operation, pressure on the hot line was much less than cold line as shown below. Hot is about 6-7 psi (left gauge). Cold cycles from about 20-40 psi (right gauge) as it is from a pressure tank. No problem except that that the shower valve/mixers tended to be very sensitive -- either cold or very hot if just nudged slightly.

The 6-7 psi on hot is consistent with the standard formula for pressure due to head (p = rho g h ... which comes out to about 1.4 psi per meter of head).

But then something happened in year 3 or so, such that the hot and cold pressures are now equal:

When showering, the hot pressure will drop to 6-7 psi as before, but afterwards, will slowly rise to equal the cold pressure. Seems that there is a leakage somewhere (defective faucet or shower fixture/mixer?) that is causing water flow from cold supply to hot lines. This caused the solar water heater tank to be filled by reverse flow from its hot output pipe! Resulting in continuous overflow from the tank onto the roof.

Had to install a one-way valve on the hot line coming from the solar water heater to stop the backfilling!

Have not yet been able to locate where the cold to hot leakage is. The faucets with hot/cold capability can be shut off via their angle valves to isolate them, but the multiple shower fixtures cannot, as they do not have individual valves. After shutting off the angle valves of all such faucets, the hot and cold pressures still become equal. So it must be one of the shower mixers? But which one.

Anyone experienced similar problems or have suggestions?

If faucet/shower fixtures or appliances like washing machines are prone to this failure mode (leakage between hot and cold), this would appear to be an issue for open-type (non-pressurized) solar water heater systems in general.

Picture of heater from another thread: What brand of Water Heater would you recommend?