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Author Topic: Blasphemy..... Solar power.  (Read 148418 times)

BruceM

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Re: Blasphemy..... Solar power.
« Reply #90 on: February 21, 2017, 07:05:35 PM »
Thanks, Carl.  I"d love to see a picture of your reflector setup!  DIY vacuum tube - a very advanced design!

For my neighbor's new place (superinsulated, double wall home in progress) we tried some of the cheap 12V Topsflow circulation pumps.  One for their in floor heat has been in service for a year so far.  My system uses a Lang D5 Vario 12V pump, which can JUST make the 8 foot lift to my panel with enough flow to fill the system at startup.  I added a circuit to slow it down after flow is established.

Casey, I certainly agree that adding PV to boost an electric hot water heater during the day could certainly be worthwhile.

I could justify the expense of a solar hat water system since it does both house heating and domestic hot water. Plus my home is off grid, so hot water storage as energy storage makes more sense. (You'd be nuts to use batteries ($) to store PV energy for water heating.)  The side benefit is that my DIY EPDM rubber sheet lined 800 gallon insulated storage tank needed for house heating (2-3 cloudy days carry through)  has a large copper heat exchanger (180 feet total of 1/2 soft copper in 4 parallel coils) in the tank that means ENDLESS domestic hot water for laundry.  I've gotten spoiled on the hot water situation. 





carlb23

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Re: Blasphemy..... Solar power.
« Reply #91 on: February 21, 2017, 08:37:06 PM »
I'll take a few pics when i get a chance.  If i can't get them to post here i will upload them to photobucket and put a link here.
« Last Edit: February 23, 2017, 06:39:10 PM by carlb23 »

carlb23

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Re: Blasphemy..... Solar power.
« Reply #92 on: February 23, 2017, 06:33:10 PM »
I took a few pics of my 8' x 12' solar shed wall and 4' x 8' parabolic trough I will try to upload them.  

http://s1203.photobucket.com/user/carlb2323/library/?sort=2&page=2

« Last Edit: February 23, 2017, 06:37:53 PM by carlb23 »

carlb23

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Re: Blasphemy..... Solar power.
« Reply #93 on: February 23, 2017, 06:34:30 PM »
I  posted link couldn't get pics to work.
« Last Edit: February 23, 2017, 06:40:50 PM by carlb23 »

BruceM

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Re: Blasphemy..... Solar power.
« Reply #94 on: February 23, 2017, 07:43:06 PM »
The parabolic reflector is a nice piece of engineering, Carl.  (Flat panels job also 1st rate.) 
What is your actuator for the sun tracking and did you do your own hardware for the tracker electronics?


carlb23

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Re: Blasphemy..... Solar power.
« Reply #95 on: February 23, 2017, 10:27:28 PM »
its a 21" linear actuator that i got for  30 dollars and a Tiny Tracker for the electronics.  the tiny tracker works great.   I could afford to move the mounting point on the actuator to get a little more travel but it is only missing about 1/2 hour of sun in early morning.  I have some constants based on the location of the trough to the house but it was my best option for the installation.   The collectors are feeding a 275 gallon tank in the basement.   I decided to opt for keeping the collector close to the house to minimize heat loss moving the water from the basement to the collectors.  Both are drain back systems 

I only use it to preheat our domestic hot water, the tank has a 250' copper coil in it that city water circulates  through heating the water before it gets to our electric water heater.   While we have natural gas at our house we generate so much electricity with our solar (33 Mwh a year) that we never need to use natural gas unless the outside temp dips below 0 degrees F or we get freezing rain which renders our air source heat pump almost useless.

We also have about 150 sqft of solar air heaters which do a fantastic job of heating our house during the day in the winter time.   On a sunny day at 25 degrees f outside the house (2675 sqft not counting the basement)will heat to 74 degrees by late afternoon. solar air heaters are very easy to build and very inexpensive. I have had zero problems with them.  I built the first one in 2004 and the second one in 2006

LowGear

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Re: Blasphemy..... Solar power.
« Reply #96 on: February 28, 2017, 08:59:38 AM »
And I'm stuck repairing gutters for the April showers.  Up the ladder, down the ladder, up the ladder, down the ladder.  Where is the glory in maintenance?

Wow.  33 MW a year.  33,000 KW is worth over $10,000 here in Hawaii.  My math must be wrong.  Of course in Wenatchee, Washington it's only worth $828. 

Casey
NPR Tipper/Dump Truck
Kubota BX 2230
Witte BD Generator
SunnyBoy 6000 + SolarWorld 245

carlb23

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Re: Blasphemy..... Solar power.
« Reply #97 on: February 28, 2017, 10:37:08 AM »
And I'm stuck repairing gutters for the April showers.  Up the ladder, down the ladder, up the ladder, down the ladder.  Where is the glory in maintenance?

Wow.  33 MW a year.  33,000 KW is worth over $10,000 here in Hawaii.  My math must be wrong.  Of course in Wenatchee, Washington it's only worth $828. 
Casey

about $5100 here, last i checked 15.5 cents Kwh

oldgoat

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Re: Blasphemy..... Solar power.
« Reply #98 on: February 28, 2017, 02:10:18 PM »
The electricity suppliers here pay $0.5 per Kwh but limit the size of the inverter to 5 Kw and according to my contract will do so until 2025. Any changes such as change of owner etc. and all bets are off the price goes down to $0.08 per Kwh. Here in summer we have at least 6 hours when it puts out 4 Kw. so i have a big credit with the supplier. Some day I will ask them to pay me that credit and I will see how forthcoming they are. Then there is another problem the tax office treats this as income so I will wait till I have a low income year before I make a grab for it.

BruceM

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Re: Blasphemy..... Solar power.
« Reply #99 on: February 28, 2017, 03:50:15 PM »
Thanks, Carl, for the details on your actuator, tracker, and system.  Exceptionally well done!

 I was a fan of air collectors about 27 years ago; the first home I built had both passive and active hot air panel heating; 600 SF of hot air panels in the south (53 degree ) roof face heated air which was recirculated through  2 feet deep, 3 inch rock under the  the concrete slab.  I did this because it was well known by then that rock storage systems generally became too mold infested to use for direct air heating. They system worked well but took a fair amount of energy to move the around; total of 3/4 HP during the sunny part of the day.   A guy named Sanderson used it as a secondary heating system in his amazing 100% solar heated homes in Vermont.  The heat output of my roof air collector was comparable to 48,000 watts of electric resistive heating; the lack of insulation under the rock storage was a serious design flaw.  The soil and rock did warm up, but the ongoing losses downward to the earth were huge. 

I prefer hot water over air panels now that I'm off grid because it takes so little power to move it.  My house heat pump is 20 watts, the solar pump about the same.  Super insulation keeps the solar hot water heating demand very low and never needs maintenance or replacement.





carlb23

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Re: Blasphemy..... Solar power.
« Reply #100 on: March 01, 2017, 12:03:20 AM »
our two air heaters are powered by small blowers .80 amps @ 115 vac  each.  The design does not take a lot of power to move the air since convection is doing most of the work.  Good sunny day outside temp 25 degrees F  indoor air 72 degrees output from air heater at 100 cfm is 145 degrees f.

LowGear

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Re: Blasphemy..... Solar power.
« Reply #101 on: March 01, 2017, 05:42:31 PM »
carlb23

State of Washington, USA has a similar 50 cents a KW rebate program that will last a few more years.  Some folks have done rather nicely by it, thank you; but not me - darn it.  However they settle up every year.  I'd be very uncomfortable with a state agency owing money from years gone by.

Casey
NPR Tipper/Dump Truck
Kubota BX 2230
Witte BD Generator
SunnyBoy 6000 + SolarWorld 245

carlb23

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Re: Blasphemy..... Solar power.
« Reply #102 on: March 01, 2017, 07:47:32 PM »
our daughter and son in law live in Olympia Washington and they had a 6kw system installed using panels and inverters  that were built in state and they do get the 50 cent rate.

veggie

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Re: Blasphemy..... Solar power.
« Reply #103 on: March 02, 2017, 02:42:16 PM »
Carlb,

Thats a really nice system you put on the shed.
I have 3 spare evacuated tube panels that need a home and heating my small barn would be a perfect application.
The wall to which I would mount the panels faces due south so that would be a great location.
In my part of the world we can get -35C temps so drainback systems are not used here. Gylcol circulation and differential temp controllers with a small circ pump connecting the system to a buffer tank and wall radiators is what I have in mind.

Carl, how do you dump your heat in summer.?
My plan is to tarp cover the panels. or...push the heat to an external radiator mounted on the outside wall.

Veggie
- 6/1 GM90 Listeroid - Delco 33si Alternator
- Changfa R175 - Lease/Neville Alternator
- JiangDong R165 Air cooled - 2 kw
- Changfa S195 (Waiting for a project)

BruceM

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Re: Blasphemy..... Solar power.
« Reply #104 on: March 02, 2017, 06:45:45 PM »
Minus 35C is pretty nasty.  I'm baffled though why that would make drainback solar unpopular. There is no water in the plumbing until the panel is hot enough to raise the storage temp.  Any system (pump) failure results in the same drained back to the tank state.