4 MWH Solar Thermal

[Dave B.]

Just an update to note another milestone for my evacuated tube solar thermal system. Just clicked over 4,000,000 WH since last March 2011. Electric conversion here would be about $800.00 or about $90.00 month. So far this system has provided 80-100% of my total dhw and home heat for the spring, summer and fall. Looking at the numbers I believe for the next 3 months of winter's worst I can expect possibly an average of 40-50% of my heating and hot water needs to be covered by the system. Add to this my 1.6kw of voltaic and 16' wind turbine charging the l-16's running the Magnum 4448 and things are good. It won't seem like it right away but in another month we turn the corner for longer daylight besides.   Dave B.  www.dcbenergy.com   

[ghurd]

Great!

Wondering if you calculated the ROI if the system was expanded?  Maybe add some on the garage?
I am simply thinking all the complicated stuff is in place and expansion may just be adding some more tubes and storage, but I could be way off track.
G-

[Dave B.]

  Yes, at this point I see a max. 4-5 year ROI at today's energy costs so it may very well be less than that as energy costs continue to rise. When my funds allow it I will most certainly add more collectors and storage as soon as I can and this even before adding more voltaic. As you know in this snow belt area of WNY we require some home heating for 9 months of the year with at least 6 months of that being full time.

  I've done my home work and yes solar is boring compared to wind but with costs at around $1.00 per watt, 10-25 year warrantees, very little maintenance, no expensive towers, noise, shadowing and fewer permit issues and neighbor conflicts for me it's now a no-brainer. Wind is still fun but for my location comparing manufactured wind and solar systems of the same capacity who offer warrantees, small wind loses the ROI to solar by at least 3 to 1 (not including a tower) Site dependent yes and your numbers for your site will vary.

  I am as excited about solar now as I ever was for wind, it just plain works and with less to think about. For those not familiar with the evacuated tube thermal system just google it. Ambient temperature really doesn't matter much to it's efficiency, it really is an amazing system.    Dave B.   www.dcbenergy.com         

[tomw]

  I am as excited about solar now as I ever was for wind, it just plain works and with less to think about. For those not familiar with the evacuated tube thermal system just google it. Ambient temperature really doesn't matter much to it's efficiency, it really is an amazing system.    Dave B.   www.dcbenergy.com         

Dave;

I think I am changing my REligion slowly but surely. I cannot keep up with the turbine maintenance. The solar, beyond tracking mechanisms just work. Hose em off, sweep off a bit of snow is about all the maintenance there is.

I have neglected solar thermal for awhile now but I suspect it is on my list. We just did a major PV upgrade here adding 1500 watts and a Midnite Classic as well as upgraded most of the wiring. I think that upgrade will carry us awhile on our RE electrical system unless we need higher inverter capacity then maybe add another stacked FX. The hobby turned into an addiction so should be easy to get fired up on relatively cheap solar thermal systems.

A major problem here is the house literally is in the timber on the south side. Tall trees to East, South and West. Solar thermal always seemed hard to do with collectors a long way from the point of use.  My PV is near the garage where there is fair solar exposure and all the RE gear is and I feed power into the house from there. Relatively easy with electricity.

I have not sorted out how to do Solar thermal other than burying insulated pipe / tubes from the exposed area to carry heat 100+ feet across the driveway.

Got me thinking on it again anyway!

Tom

[Wolvenar]

Yes, you got me thinking too.
I will start moving into mostly solar stuff as well
I have to start thinking of the fast approaching time I wont be able to do big things.

I might not yet give up on wind however.
I need to see through one last large build, just to say I did it.

Ok where is that calculator.. and drawing board..

* Wolvenar mutters to himself... ok I would need to move the pv off the garage to make room for the thermal.....

[rossw]

The whole "ROI" equation is unfortunate but necessary for most of us.
Being entirely off-grid for power, but having two home-offices and a bunch of essential equipment means I do burn a lot of kWh/day, and when that was comming mostly from propane, the numbers did work. Purchased a modest 1.2kW upgrade, which saved so much money I was able to add another  1.8kW upgrade the next year just on the money I saved on burning propane. And the next year was an eye opener - not running the generator at all for months I was in the silly situation of having to light a FIRE in the middle of summer just for domestic hot water! So the savings on that years propane payed for a 60-tube evacuated tube water heater. They are indeed good... and I'm wondering what to upgrade next. More PV I think, for those crap days where there is some sun but not quite enough to avoid running the genset. (And any surplus PV can always be used for heating)

[Dave B.]

  Looking at last year and even as mild as it was I would have blown through 100 gallons of propane by now for home heat. At a minimum this would be $250.00 for heat alone say nothing of the dhw (then electric). I converted my forced air furnace to hot water with a heat exchanger, my propane tank is long gone out of here and my ball and chain relationship with the propane company has ended, gee what a shame.

  A very hot shower is 115 deg F. Most people are comfortable in their home at 72 deg F. Our bodies are 98 deg. F. You can easily pull useful heat for your home from water temps as low as 120 deg f. and even less. An evacuated tube solar hot water system can easily cruise at making  100 deg F. water on overcast days and in direct sun most are throttled back to keep temps to 180 deg f. max. Steamback and stagnation temps. can rise up to 350 - 500 deg f.

 Old school dictates that we purchase fuels that burn over 1000 deg f. to heat ourselves to 72 deg f. Is this nuts or what ? For me now it's hot water storage for dhw and home heat and battery storage for electric, both fueled directly and efficiently by the sun 93,000,000 miles away with no delivery charge. This to me now is much more exciting than wind and I see others here now also changing their ways toward solar.  Dave B.    www.dcbenergy.com       

[ghurd]

"and I'm wondering what to upgrade next"

Tubes?
Most of the Big Buck 'tube' stuff is already in place?  'puters and pumps and such.

PV?
All the Big Buck 'PV' stuff is already in place.  Batteries and controllers and such.

Tubes are more efficient...
PV is more flexable to use...
I just gave myself a headache...
G-

[rossw]

Ghurd: yes, I agree the evac tubes extract more energy from the sun. So DHW and heating in winter is a benefit.
However, I would need a *LOT* to heat this place. (8800 sq feet roughly). Be better spending my money on double-glazing the windows which I wish now I had done in the first place.

PV however represents better use for me. In winter, I'm always looking for extra power because of the shorter days of sun. That will get my batteries charged more quickly, and anything surplus can be used to heat the place. The advantage is that in summer (when we start earlier) the batteries will recover more quickly - possibly even be getting enough to cover the water pumps etc when we get up. In summer I don't need any more heat than the existing evac tubes provide in the way of heat, so PV is useful all year....