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Flat Panel Solar Hot Water Systems


ladner

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Does anyone have any experience with an Axol Flat Panel Solar Water Heater as distributed by GreenHome, in the strip mall on the carretera in Ajijic that also contains the bagel place? For the same size tank, the price is lower.

Maybe there are other brands of flat panel units distributed lakeside but we haven't found them.

TIA

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STI Solar Technology offers both types of systems, vacuum tube and flat panel.     Don't know the Axol brand.

Vacuum tube based systems typically provide higher efficiency, more capacity, and longer life with better reliability, plus a wider range of sizes and types, than do the flat panels.    Likely > 98% of the systems sold / installed are the tube type.

 

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Also the flat panel is heavier and needs better anchoring for wind. They are cheaper but you get what you pay for.  With a vacume tube the water is boiling innthe tanh. With flat panel max 180f.  Just a less effecient system.  I doubt you could go 4 days without sun with flat panwp but with tubes and copper tube in the tank you can.

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About 18 months ago, we went with a system from GreenHome after obtaining bids from them and two companies out of GDL.  Prices were similar so we went with the Local company.  We have been extremely dissatisfied with the product, the service and the attitude from the company.  Their technician, Arturo, seems to be a hard working and honest man.  He has been to our home countless times since we purchased the product and has tried (in vain) to provide us with adequate, consistent hot water.  During his last visit about a month ago, he mentioned the gelatinous crystals are a byproduct of this type of system and it is only going to worsen.  We are ready to rip out the system, throw it in the trash and go back to our "on demand/ al paso" type of gas hot water heater that used to provide us with nonstop, HOT water with great pressure.  We've been so frustrated with this company and product.

In this situation, I urge caution based upon our experience.  I've talked with one of the two GDL companies we considered and he looked over the system and explained that we were sold a system that only provides half of what our water needs are.  He offers this as the explanation for the inconsistent hot/warm/cold changes throughout our showers and bath.  When I gave him the price we paid, ($16,000 pesos), he almost fell out of his chair.

We plan to give GreenHome one more opportunity to either replace the system, add onto it or offer some kind of compensation while removing the unit from our house but I am not hopeful.

I encourage you to check out a different company.

Valerie :)

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Our problem is that water going into the big gas water is so cold that it quickly cools the remaining hot water. Then you have to wait at least one hour for it to get real hot again. I don't see what can go wrong with a solar water heater. No moving parts, no electricity. Is this the 150 litre model? A solar heater would help a lot for the small amount of hot water we use, and only a problem for 3 months a year. If you, or Greenhome, would like to sell it as used, I would like to have a look at it. PM me for details if you, or they, are interested.

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Valerie, was this a vacuum tube system or flat panel? How big is your tank, 150 litres or less? I understand your frustration. Thanks for sharing.

Our current vacuum tube system is not providing as hot water as it used to. Maybe the tubes can be replaced, or we need a bigger tank. We are thinking we will get Solar Technology from Guad to investigate since it is their product we have.

Our research online also is telling us that the flat panel is not as efficient as the vacuum tube, unless you can keep the panel facing the sun. With our sun moving north to south, we couldn't do that.

 

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Flat panels have the advantage they can be installed on sloped roofs.  The standard units with the big hot water tanks are heavy and bulky and you have to have the right location for them and a roof strong enough to carry the weight.  That was the deal killer for us unfortunately, neither work without screwing up the architecture of the house.

If I had solar hot water I would most certainly make sure the water feed for it is carefully filtered and softened.  What I did was find the most efficient water heaters available here and then add additional insulating blankets.  This cut the gas consumption considerably.

I've got solar for my pool and 100 percent solar electric and would love to have solar hot water but I can't figure out how to have it without screwing up our roof top patio.  Even had STI, our solar electric supplier, try and figure it out.

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Ladner, I believe we have the Flat Panel type and it's 150 liters.  The man from GDL who came after about a year of our frustration took a look at it and said we needed to have two of the 150 liter tanks to satisfy our water needs.  While we are only 2 adults, I do have a deep bath tub that I enjoy.  Well, used to enjoy.  Now, it takes about 10 minutes to get 1/3 full of hot water.  I then have to wait about 10 more minutes before I can turn the faucet on and get another 1/3 of hot water.  It's ridiculous that it takes 20-25 minutes to get a tub of hot water for a bath.  The representatives from Green Home calculated the size of tank needed based upon the knowledge that I take full, HOT, baths throughout the week and they assured me that this product would provide the hot water I needed.  As irritating as that has been, even the ever-changing temperature during a shower continues to frustrate both of us.  We never had these problems with our original Al Paso (on demand) gas water heater.  It used to take about 8-10 minutes to run a tub full of really hot water with our old system.

We have been so happy with our Solar panels from ESun for lowering our CFE bills that we thought we should go ahead with the Solar hot water system too.  In hindsight, a really bad decision for us that has cost a great deal of money and lots of frustration.

In our situation, we have areas on the roof that are sloped and flat so either system could have been used.  I encourage you to do your homework and I hope you have much better luck than we have had on our system. :)

Valerie

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In 2008 I moved into my newly remodeled home which had both photo Voltaic and hot water vacuum tube solar panels panel tubes. I couldn't be happier. Thank you eSunEnergy.

Make sure that the company you purchase from has a good reputation. Apparently there are those who keep on going out of business, who reorganize under a new name and therefor don't have to honor the older guaranty because they are a new company.

eSunEnergy's greatest strength is that they have always been there to take care of problems free of charge, should they occur.

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Val,

No luck involved. If your system was installed to give direct supply, without going through your del paso heater, 150-160L would take care of normal needs for two people. However, your needs seem to be higher, especially with that deep tub being able to empty the storage tank with one bath. Worse yet, when filling the tub, you are simultaneously adding half a tank of cold water to your solar storage tank, cooling it off immediately. Therefore, you have to wait a bit.....or longer.  Such systems cannot handle such high volumes in such a short time.  Perhaps you could add a second or third system, in series with the first, to serve your needs. That is the approach used by the laundry on Lopez Cotilla, in Chapala, and they have sufficient hot water for multiple high capacity washing machines.  Your design guy probably knows this, but may not have understood your deep bathtub usage at all, as it is not something that most Mexicans would know about; quick showers being the common method of bathing.....sometimes cold ones.

Our 160 Litre vacuum tube solar hot water system served our needs quite well; even with a few cloudy days. But, we did shower expeditiously and did not have a dishwasher.

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I've contacted Ron with STI and hopefully, his technician can take a look at our pathetic system and make some suggestions.  All 3 companies who came to give us a bid/quote measured the tub, calculated the liters, etc. and ALL assured me there would be NO problem filling it with really hot water within about 8-10 minutes.  Clearly, not accurate.

We'll see what STI has to say and go from there but right now, I'm ready to chuck it all and buy another Al Paso/on demand hot water heater.  That served us well and I'll just pay a little more for gas refills. :)

Thanks,

Valerie

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It is best to get the top of the line system. You do not use the water in the tank. Your water flows through a spiral coper tube inside the tank. The water in the tube is heated as it passes through the extremely hot water in the tank. This allows more hot water than the tank capacity. Also stays hot longer because you are not filling the tank with cold water when you use the hot water.

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The copper coil (heat exchanger) systems do also lose heat as the cold water picks up the heat from the tank.    

From the tank point of view, think about it like a battery being discharged, no matter what the heating technology is.  

Bigger = lasts longer / more capacity & "power".

However, 2 things about the tube systems help a lot compared to the flat plate systems:    

1 - generally the tank sizes are larger than 150 liters to begin with, so the cooling effect is less of an issue

2 - the vacuum tube technology heats quickly and with very high efficiency, and so can generally keep up with even extended hot water use in good sun conditions.

Having a larger tank (the tube systems go up to 340 liters) not only makes the daily use much more enjoyable, it can retain hot water for several days in non-sun conditions, depending on the volume of use.     So there is much less need to go to the backup at times like that, with the associated gas $avings.

Have never heard anyone say they wished they had a smaller system.......!  ;-)

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