A Large Home-Built Solar Hot Water System in Iowa
 

I found this on BuildItSolar a little while back. Its a great install of a fairly large solar water system. I found it interesting how he made the collector separate from the casing. This simplifies somethings and makes other things more complex. Anyway, he goes into some very good detail on how he constructed the panels and shows some nice tricks he came up with.

Solar Hot Water System

http://www.krystofiak.com/solar/solarImages%5Csunny.jpg

I would like to know how much these systems cost, and how you size them.

His collector array is 8'x24', which is big enough to mostly fill my backyard. It would just about cover the south-facing half of the roof of my garage, which is partly shaded by my neighbor's tree.

Builditsolar.com is an amazing resource for this type of info.

Here is a page on sizing the collector. How much solar collector area do I need to heat my home?

Cost is pretty variable depending on how you build the collector and what materials you use.

I'm planning on eventually heading in this direction with my house, but it needs a lot of insulation and sealing work first.

Graph:
http://andyschroder.com/output/5008739239360360.png

This curve has an unfortunate shape. I only need to heat the house from day 320 to day 90 (Nov 1 to Apr 1), at most. But that's when the system's output would be the lowest. I see an average around 0.5KWh/(d*m²) in winter, and you can see from the blue line that you're going to need a backup system as well.

It looks like I'd need about 60m² to provide most of my home heating needs! That's 600ft² of collector for my 600ft² of conditioned space. But perhaps such a system would be oversized. With a 400ft² collector, it would fully heat my house on sunny days in February and March, and still assist on partly cloudy days.

The scenario for hot water is better. I can get about 1.5KWh/(d*m²) most of the year, so I'd need 100ft² of collector, plus a backup system for half of winter.

I thought solar might allow me to cancel my contract with the gas company and use a tiny amount of electric heat as a backup, but it looks like that's not going to happen.

There are parts of the country with 2.5 times as much sunlight as Buffalo, so chances are the numbers will work out better for you.

I agree, its disheartening to see the collection available in winter. I can get roughly .75 kWh/(d*m^2). As it is based on my usage last winter I use ~130 kWh of heat per day in the worst of winter. That means I'd need 1850 sq ft of collector! Or, I could improve the house to loose less heat which is a much more viable and worth while idea.

http://ecorenovator.org/forum/attach...1&d=1285423711

How do the vacuum tube system fare in comparison to the flat plate type?

In the winter, its all about total surface area to capture the heat, whilst vac tubes have less losses than a flat collector, they don't have a lot of surface area so you will need lots of them. Also they are not DIY, so its better value to not use vac tubes when you can make your own large collector arrays relatively simply.
Snow build up on vac tubes can be a problem also, the gaps between the tubes allow the snow to grab a hold and because they are better insulated the snow doesn't melt and slide off as it would on a flat plate collector.
The typical heat pipe inside the vac tube doesn't start working until it gets to 40 degrees Celsius, this means under cloudy adverse conditions they are not as efficient as flat plate collectors, so will not harvest as much energy per unit area as a flat plat collector in these conditions, sales people will try and tell you otherwise.

Cheers
Mike

Solar water heaters
 

Yes this is a great information, I do agree with that solar water system is nice resource. I do not know exactly but i think that solar system does not have high cost. It works efficiently and saves money and time.

How often does the tank get to your max temperature in the winter? in the shoulder seasons? any time there is sun and the pump is off that's wasted heat.

Maybe a seasonal thermal store is in order? 3000 gallons methinks. That's a 7.37 ft-per-side cube. build it with more insulation, especially on the floor contact area. More house treatments would be much better however.