Solar thermal system for DHW

[mikeathens]

I am sick of the F'ing propane company nickle and diming me because I don't use "enough" propane. Most recently, I got a notice of a "tank rental fee" of $60. I was going to hold off on a solar thermal system for DHW, but now I'm thinking it might be OK to go into more debt for it. Then I can tell them to come and get their f'ing tank out of my f'ing yard and go f themselves. (sorry, this whole thing just rubs me the wrong way). We only use propane for hot water in a Bosch tankless system and for cooking, the major usage being for DHW.

A friend of mine looking at the same thing found this system:

(broken link removed)

I was thinking that I'd have to shell out about $8K for one of these. Does anyone know anything about this company, the quality of their products, and the actual performace of the system above? This price seems too good to be true. But, if it is, with the federal tax credit, you'd be looking at around $2K (+ another $3K for two feet of copper pipe :bug: ).

OR

Does anyone know of a reputable company that has good prices on a complete system (performance and aesthetics are both important factors)?

Mike

 

[steam man]

I'll be installing a 120 tube system from Silicon Solar in the next few weeks. I know of another person on this forum who uses their Sunnmaxx tubes. Supposedly they are rated higher in efficiency than most of the other brands. I think they are one option if you can do some of the installation at least. There are a number of companies that do package deals. You may find a local outfit that does complete packages. I only have one thought though-how much propane do you actually use? You could then figure your payback.

 

[mikeathens]

Well, steam man, we go though about 175 gallons per year - about $470+/-, $40/month. I don't know how much of that goes to our cook stove, but the majority is for water heating. A friend of mine said he uses about 20 gallons/6 months for cooking.

So maybe $31/month for hot water (11 gallons or so). I plan on keeping the stove and switching to a portable 20 gallon tank for that.

So...what do you think about the system/package in the link? For somthing like this, I really don't care too much about "payback periods" - if that was the case, I wouldn't have installed the 4000 wat PV array on the house

A friend of mine and I would be doing the install(s), so that's not an issue. The place that installed my PV panels has a system for about $9000, installed. So, I was just wondering how this system compares with theirs (the company is Dovetail Solar www.dovetailsolar.com ). They use Heliodyne for their flat-plate systems.

 

[steam man]

If your more than capable of doing the work the silicon solar set up should be fine. I am leaning towards evacuated tube collectors since they seem to be more efficient under less than ideal conditions. There are advantages and disadvantages to each but each set up would do the job. I have been to Heliodynes factory and talked with the engineers. They have a quality product. The dovetail solar price seems to be typical for a DHW setup. You would get the federal tax credit of $2000 and any state credit for the install. In Maine a licensed contractor has to sign off on it to get that credit so that is a consideration. If you want to screw the propane supplier you'll still have to think about back up heating so there is a cost involved there. A solar storage tank with backup electric elements sounds like a plan. 175 gal/year propane at app. $470.00 comes out to $2.68gal. That seems like a cheap way to heat to me. Plan on it going much higher. But I like the idea of getting off fossil fuels. I agree about the PV payback-way too long.

 

[mikeathens]

I think I'm going to go with the silicon solar evacuated tube kit (two panels), and supply my own storage tank - most likely a Marathon water heater, 75- or 85-gallon. Now I'm thinking that I should get the water jacket for my Heartland Sweetheart, and run another circulator pump and loop into the water tank for winter DHW. Man, this is fun.

With any luck, I will have little electricty into my DHW, other than pump power.

I have a lot of research to do for this system. One big question I have is of overheating, especially the possibility that if the tank temperature got too great, that the water jacket (or collector temperature) could get too high? I read Craig's and woodheat.org's articles, anyone know of other resources?

 

[TMonter]

Why not just buy a propane tank at Home Depot and get rid of the one outside in the meantime Mike? You can get a large enough one there I don't believe it would require a vaporizer even in cold weather and they aren't super expensive.

 

[TMonter]

I have a lot of research to do for this system. One big question I have is of overheating, especially the possibility that if the tank temperature got too great, that the water jacket (or collector temperature) could get too high? I read Craig’s and woodheat.org’s articles, anyone know of other resources?

I do know you can set most systems up with a relief to vent temperature or pressure through a heat dump. It's basically a hot coil with a fan venting outside.

 

[mikeathens]

Why not just buy a propane tank at Home Depot and get rid of the one outside in the meantime Mike? You can get a large enough one there I don't believe it would require a vaporizer even in cold weather and they aren't super expensive.

Home Depot...DUH!! I have a Lowes up the street, and HD is about 20 minute drive. For some reason, I never think to check it out. I will do that. Lowes only had 20-gallon tanks. I originally wanted to get 2 X 50-gallon with an automatic switch-over so that I could get one filled while I'm using the other.

Also, around here, there are about 3 companies selling propane (for delivery). I wonder what if they will deliver for such a small tank, and what their "fuel surcharge" will be. I suspect it's somthing equivalent to a rental fee.

 

[Highbeam]

Even if they have an upcharge for privately owned tanks, you will be better off since you only pay it IF you need a fill up. You also have the benefit of price shopping the suppliers if you own the tank. You can even paint it to camoflauge it. I miss my old gas range/oven. This new house is all electric and has a nice glass cooktop range but I would prefer a cheaper gas setup.