Political Ramblings

[punk-a-doodle]

Do you have any photos of those tanks TT? What are they typically made of?

 

[thaiturkey]

Here's what is probably the roof of an apartment block showing the tank arrangement for each home:

http://www.istockphoto.com/stock-photo-21253128-water-tanks-on-a-roof-in-cyprus.php

I don't know what material is used in the Mediterranean but it's probably stainless steel covered with a weather proofing compound. Ours in Thailand is a double skin stainless steel tank. It's shaded from the sun so we aren't set up for free hot water and will need to re-plumb the house for hot and cold. Plastic tanks such as the one being delivered by truck in this link are cheaper and becoming popular:

http://www.memock.com/tag/thai-water-tanks/

Any material that will withstand sun and rain would be OK, I should think. You pump water up to it through a float valve system and draw down the hot water through the house system as needed. Better than a roof structure would probably be a separate tower, high enough to give the required head of pressure. I suppose that in areas where temperatures can fall below freezing so precautions would need to be taken for the winter months.

Google shows many images of roof tanks linked to solar panels. I think that water circulates through the pipes in the panels and heats up quicker.

 

[punk-a-doodle]

Thanks! They look completely different than what I was picturing, and sound like a great idea. Ugh, if plastic tanks make the water taste anything like bottled water, I'd have to go with metal myself.

 

[thaiturkey]

Thanks! They look completely different than what I was picturing, and sound like a great idea. Ugh, if plastic tanks make the water taste anything like bottled water, I'd have to go with metal myself.

I think that you'll find that plastic tanks are properly lined. My preference is stainless steel. Ours is seven years old and looks like new with no residue inside. We filter water that's used for cooking and drinking just to be on the safe side but that's a comment on the supply rather than the tank.

 

[rufus]

Are we talking about solar water heaters or a household water supply? Solar water heaters in cooler climates have a tank that circulate a medium, usually peanut oil, through the collector plate and then through a heat exchanger with the water. This avoids freezing problems. In places like Israel they don't bother with this; they heat the water directly.

In places like Mexico, the household water supply first goes into a very large holding tank that is often located under ground. It is called an aljibe (al hee bay). From there a pressure pump takes it up to a tank on the roof top called a tinaco. They used to be made of tin, but nowdays they are made of black plastic. This inhibits the growth of algae and other things.

The purpose of the aljibe is to make sure the household has sufficient water on hand for those times when there is no water in the municipal system. Don't take the lid off of the tank; you probably won't like what you see.

The purpose of the tinaco on the roof is to build pressure. In a lot of places the water pressure is very low and often unreliable.

Whatever type of solar water heater you need is dictated by the local geography and reliability of the municipal water system.

 

[thaiturkey]

Are we talking about solar water heaters or a household water supply? Solar water heaters in cooler climates have a tank that circulate a medium, usually peanut oil, through the collector plate and then through a heat exchanger with the water. This avoids freezing problems. In places like Israel they don't bother with this; they heat the water directly.

In places like Mexico, the household water supply first goes into a very large holding tank that is often located under ground. It is called an aljibe (al hee bay). From there a pressure pump takes it up to a tank on the roof top called a tinaco. They used to be made of tin, but nowdays they are made of black plastic. This inhibits the growth of algae and other things.

The purpose of the aljibe is to make sure the household has sufficient water on hand for those times when there is no water in the municipal system. Don't take the lid off of the tank; you probably won't like what you see.

The purpose of the tinaco on the roof is to build pressure. In a lot of places the water pressure is very low and often unreliable.

Whatever type of solar water heater you need is dictated by the local geography and reliability of the municipal water system.

What I have written about is a water tank or tanks placed directly in the sun in order to heat up the water and mounted high enough to give the desired head of pressure. If I was to build another house here I would plumb it for that and for a cold water tank. From my experience of such systems in the Mediterranean, it works well provided that the tank is big enough and the hours of sunlight are long enough. Every little helps, though.

 

[MamaRoo]

What I have written about is a water tank or tanks placed directly in the sun in order to heat up the water and mounted high enough to give the desired head of pressure. If I was to build another house here I would plumb it for that and for a cold water tank. From my experience of such systems in the Mediterranean, it works well provided that the tank is big enough and the hours of sunlight are long enough. Every little helps, though.

I'd like to do something like that and run it through my on-demand water heater. In Seattle it's unlikely that the sun would warm the water enough for a shower, especially in the winter, but it would help preheat the water for the on-demand.

 

[Happy Chooks]

Quote:
We bought a solar hot water heater a couple of years ago. (State was offering a great rebate/tax incentive) I believe it's a Solahot. No pumps, it is thermo-siphoned by the heat. It's still in the garage though on the DH's *cough cough* to do list. In his defense, we have a really high, steep pitch roof and it's going to involve a crane to install it.

The in-laws have the same one and it's installed. They are super happy with it. They do have a tempering valve though as the water gets hotter than 180 degrees in the summer.

 

[rufus]

We bought a solar hot water heater a couple of years ago. (State was offering a great rebate/tax incentive) I believe it's a Solahot. No pumps, it is thermo-siphoned by the heat. It's still in the garage though on the DH's *cough cough* to do list. In his defense, we have a really high, steep pitch roof and it's going to involve a crane to install it.

The in-laws have the same one and it's installed. They are super happy with it. They do have a tempering valve though as the water gets hotter than 180 degrees in the summer.

You need a safety valve on them. Especially here in the Arizona desert. You can raise steam just my squirting water on a tin roof.

 

[kevs-chickadees]

Just don't buy a Fafco system as a solar water heater, completely worthless! As a pool heater they are eh ok.