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Rick H Parker

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Reply with quote  #11 
Going back to the night stand idea. Automotive heater core, blower fan and electric control valve is most of the hardware one would need. 
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Rick H Parker
Kansas, USA
Electronics Engineering Technologist

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Reply with quote  #12 
That is a lot of very excellent information, thank you very much my friend I appreciate your response
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Reply with quote  #13 
How many 4x8 panels would you reccomend to heat a 275 gallon tank? So just to confirm you think that would work better than 5 55 gallon drums, one for each heater?
stmbtwle

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Reply with quote  #14 
Sorry, I live in Florida and my house is not as well insulated as yours so I cannot say, also I am not familiar with your climate. I think you get a lot more sun.

You could try a single drum wrapped in lots of insulation and plastic, and one panel, connected to one room, and expand as you work out the bugs (there WILL be bugs).

I think a single tote would be cheaper and more efficient in the long run, as a single pump with valves could serve several rooms, where with drums you'll probably need a complete setup for each room. Also with drums, some rooms are going to use more energy and run out, with a tote they could 'share'. (That could be a good thing or a bad thing).

I'd start with one drum and one panel, that'll get you started. You can reuse most of the components if you decide to switch later.

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Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
Rick H Parker

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Reply with quote  #15 
How many 4x8 panels would you recomend to heat a 275 gallon tank?

One per 55 gallons is a good guess. You might need to adjust the ratio as you see how things shape up.

So just to confirm you think that would work better than 5 55 gallon drums, one for each heater?

If your thinking individually insulated drums, one 275 gallon tank would do better. The less surface area you have for a given volume of water, the less the heat loss.


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Rick H Parker
Kansas, USA
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stmbtwle

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Reply with quote  #16 
A single tank would be easier/less expensive to insulate and plumb up too.

As to how many solar collectors, that depends on conditions, which is why I suggest you start with one. Consider the first setup an "experiment", and go from there. You can keep adding collectors till you get the results you want.

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Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
stmbtwle

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Reply with quote  #17 
Brian I've been thinking about all this and it looks like a 100% hot water setup may be a pretty expensive way to go. How many months a year do you think you would be actually using the system? Bear in mind that the rest of the time it would be sitting idle and have to be covered. Assuming you already have a heat pump, what about grid-tied PV solar? PV works year round and would help with your AC bill too. For what you get, it might be less expensive.

Considering what little I know of your home, I'd guess it's about 32x70 feet. Using this VERY ROUGH calculator: http://www.calculator.net/btu-calculator.html?roomwidth=32&roomwidthunit=feet&roomlength=70&roomlengthunit=feet&ceilingheight=8&ceilingheightunit=feet&insulation=good&temperature=40&temperatureunit=f&calctype=heat&x=55&y=11

So according to the calculator you need about 37000 btu/hr. Times 24 hrs is 888,000 btu.

A btu is 1#of water x 1 degreeF.  Assuming you need a minimum water temperature of about 90F, and you can heat the water to 160F, that's a temp rise of 70F.  888000 btu/70degrees= 12685# of water needed. A drum holds about 450# of water.  888000/450= 28.2.  So you'd need 28 drums of water @ 160 to heat the house for 24 hrs.  If you can insulate and install a drum for $100, that's $2800, and we haven't even gotten to the solar collectors and other hardware yet.  

That's not very encouraging.  I'm hoping someone can find an error somewhere.

Of course you won't need that much heat all the time, so a smaller system may do the job.

Another concept which would be a whole lot less expensive would be air collectors.  By their nature air collectors are cheaper to build, and there's no storage cost involved.  They heat air, and pump it directly into the home during the day, offsetting the cost of conventional heat (which you'd still need at night). 

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Solar is like the wind. It may be free, but putting it to work isn't!
Willie, Tampa Bay
Gordy

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Reply with quote  #18 
Brian,
If you use a larger water storage container, you only need one pump from storage to the house. Look at a big box store that carries hydronic heating parts, they will have zone heating manifolds with electric solenoid valves operated by a thermostat in each zone. That diverts the water flow to the zone that the thermostat is calling for heat.

If you are still thinking of the screen hot air collector. An old school way to store the heat is a large insulated box filled with 3 inch and larger rock, or jars and bottles full of water. The jars would be set on shelves that are sealed on one end and the sides, the next shelf would be open on the opposite end and so on, so that the air take's a serpentine route through the box. Hot air is blown in at the top with cooler air coming out the bottom during the day, at night you remove the hot air from the top as needed and the cooler air reenters at the bottom.  I did not see if you mentioned how tall your crawl space is. Is it tall enough to put any storage containers down there?

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Gordy,
Minnesota
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Reply with quote  #19 
Quote:
Originally Posted by stmbtwle
Brian I've been thinking about all this and it looks like a 100% hot water setup may be a pretty expensive way to go. How many months a year do you think you would be actually using the system? Bear in mind that the rest of the time it would be sitting idle and have to be covered. Assuming you already have a heat pump, what about grid-tied PV solar? PV works year round and would help with your AC bill too. For what you get, it might be less expensive.

Considering what little I know of your home, I'd guess it's about 32x70 feet. Using this VERY ROUGH calculator: http://www.calculator.net/btu-calculator.html?roomwidth=32&roomwidthunit=feet&roomlength=70&roomlengthunit=feet&ceilingheight=8&ceilingheightunit=feet&insulation=good&temperature=40&temperatureunit=f&calctype=heat&x=55&y=11

So according to the calculator you need about 37000 btu/hr. Times 24 hrs is 888,000 btu.

A btu is 1#of water x 1 degreeF.  Assuming you need a minimum water temperature of about 90F, and you can heat the water to 160F, that's a temp rise of 70F.  888000 btu/70degrees= 12685# of water needed. A drum holds about 450# of water.  888000/450= 28.2.  So you'd need 28 drums of water @ 160 to heat the house for 24 hrs.  If you can insulate and install a drum for $100, that's $2800, and we haven't even gotten to the solar collectors and other hardware yet.  

That's not very encouraging.  I'm hoping someone can find an error somewhere.

Of course you won't need that much heat all the time, so a smaller system may do the job.

Another concept which would be a whole lot less expensive would be air collectors.  By their nature air collectors are cheaper to build, and there's no storage cost involved.  They heat air, and pump it directly into the home during the day, offsetting the cost of conventional heat (which you'd still need at night). 
Green Energy Living

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Reply with quote  #20 
Thank you so much my friend, that is a lot of very good information and I was wondering about the very thing that you just answered a question to yes, it's unfortunate that this house is so big I just got the home really inexpensively and I really don't even need all this space. I'm thinking about just blocking half of this home off and putting a door and heating a smaller area unless my children are visiting. I am very familiar with how to build solar hot air collector and I'm very familiar with solar hot water but I'm not at all familiar with solar PV. I'd rather stick with what I'm more familiar with doing. I probably will build several solar hot air collectors and use those but also my house doesn't face directly south so I will have to angle my solar warm air collectors. The backside of My home faces about 55 degrees Southeast. What angle should I tilt them at? Directly south? You were pretty close on the dimensions of my house the actual dimensions are about 27 by 74. I have a 2 1/2 ' crawl space under the house.

Let's revisit the coil under the forced air furnace idea connected to a 275 gallon tote tank. The reason I was concerned with heat loss through the ductwork is because the forced air furnace is on one side of the house. One time I built a solar collector on the roof of the place that I used to work at. The output temperature was 220 degrees. They great solar collector there was tall ceilings in the shop. I wanted to bring the heat down to just about 3 feet above head level. By the time the Heat came out it was like 80 degrees less. I was shocked at the heat drop but the pipe was not insulated. My duct work is but my ductwork is also a lot larger and the fan is a lot larger also. Knowing that information do you think it could work? I could just close off the registers on the side of the house that I am not using to make it more efficient when I'm only there, just heating half of the house that I use more often. Thank you so much for your help, it's greatly appreciated.
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