Simple and Inexpensive Imported Thermosyphon Solar Water Heating Systems

I have been curious about how the commercial thermosyphon water heaters of the type shown in the picture just below perform and hold up over time.

These systems are available from a number of producers (from China and elsewhere) and the prices are very attractive. They are widely used in a number of countries but not common in the US.

Henry has been using one of these systems for a while and is getting good results -- the details of his experiences with the system are listed below.

The systems come in several different designs to meet the requirements of pressurized and unpressurized home plumbing systems and to satisfy a variety of hot water demands.

I would like to hear from others who have had experiences with these systems -- if you have such a system please let us know how it has worked out.

The details on Henry's system...

We recently retired to Yucatan and replaced our water system, as we will be living here 7mo a year.

Water here either comes from a well or a municipal source. If the municipal source, it is delivered via low pressure hoses to residential cisterns.  This water (either style) then is pumped to a rooftop tank (ours is 1100 liters)  to provide pressure in the house.  Since water must always be pumped to the roof, incorporating a solar heater incurs NO additional operational cost. 

Our local hardware store had a special in their flyer for a 120 liter, 10 tube, thermosyphon heater for $4500 Pesos (about $275 USD). This is designed for our gravity fed systems here. The frame and external tank are stainless steel and the interior tank is polypropylene. There is about 2 inches of foam insulation between the two. 

Assembly and installation was straightforward. 

Water is HOT!  You have to be VERY careful not to scald yourself. If you do not use some hot water daily, there are periodic bursts of steam and boiling water that come out of the overflow vent during the day.  After 2 days of no sun, there is still hot water, but not scalding hot. 

We are 80 yards off the ocean, and with the big northerly winter wind the frame and outer tank are quite rusted. I have started waxing it but I am probably too late.

There also was the issue of both the cold and hot water connections coming off the bottom of the tank. I added a hot water pickup inline to draw the hot water from the top of the tank, which really should have been in the design. 

The brand name is Guardian. It probably saves about 300 Pesos in electricity every 2 months, so the payback is reasonable. But it's really the solar hot water heater "toy" I've always wanted. I just wasn't expecting 200+degree water out of it.


Some pictures of Henry's system:

I don't think I would have a hard time getting used to Henry's climate and living on the beach :)




The 1100 liter (290 gallon) tank.



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