Doing the Math on Solar Water Heaters

[raja]

Re: Doing the Math on Solar Water Heaters

In order for it to be safe you have to compost it properly.

First, one uses a soil oven, used for sterilizing soil from diseased ground (such as viruses, mold and bacteria that plants leave in the soil).

I haven't done any in-depth study on this subject, so correct me if I'm wrong . . . .

If you are the only one creating the poop on your property, why are you concerned about disease?
As I understand it, the danger from human manure is that one can contract communicable diseases such as cholera and hepatitis. But unless someone who has these diseases is using your toilet, what is there to worry about?

Certainly, some sort of composting would be more convenient than just using a chamber pot and throwing the contents on the compost pile. But as far as health safety concerns, I think you may be going way overboard . . . .

What I'm saying would apply also for a healthy family.
However, if your plan is to regularly entertain guests from 3rd world countries, there may be a concern.

[lektrode]

Re: Doing the Math on Solar Water Heaters

Note I didn't say you cannot do it - I said the process is inherently not very efficient.

Try using a pure electrical heater some time to see what I mean - this impacts the scale of windmill which charliebrown was looking at, as well as the amount of storage necessary.

oh believe me, i know painfully well how "100% efficient" electric heat is - after renting a place with electric baseboard heating for _ONE_ winter - its 'efficient and cheap' alright - for the builder/installer - quite profitable too...

but for the end user?
methinks burnin yer furniture would be cheaper

.....
What I'm saying would apply also for a healthy family.
However, if your plan is to regularly entertain guests from 3rd world countries, there may be a concern.

dont panic, but short of moving to idaho, isnt that whats happnin already ?
i mean, with 'free' med ins an all, by the end of next year, we'll be 'entertaining' plenty of em...

;)

[flintlock]

Re: Doing the Math on Solar Water Heaters

In my 30+ years experience working on homes the biggest single miscalculation in figuring payback on green energy devices like solar, instant hot water, etc is the failure to factor for repairs. Increased complexity usually means less reliability and this is no exception. Damage to panels from storms was also mentioned earlier. No way you would go 10 years around here with no damage. The lack of qualified people to work on this stuff can leave you being gouged, often by the original installer.

On demand water heaters were the rage a several years ago. Plumbers were pushing these due to the huge margins. People were not only spending more upfront on the part and installation, but often needed a gas or electric upgrade to their home just to provide the massive energy burst needed to make them work. They are more complex and we are seeing far more repairs needed than would be needed for a plain old fashioned WH. Who could have guessed?

I can understand using solar for places with an unreliable grid or just for those who want it. It great for powering gates or lighting where running underground wires is not practical or cost prohibitive.

As far as solar affecting fire fighting. There are some recent NEC code changes designed to address some of this.

Recently a customer was bragging about her new hybrid WH. Needed a new 240v line run the length of the house.$$$$ She already had nat gas. Why go electric??? Same reason some HVAC guys push heat pumps around here. They are being paid rebates by power company.

[flintlock]

Re: Doing the Math on Solar Water Heaters

Another one that intrigues me is geothermal. Cost has to come down though.

[lektrode]

Re: Doing the Math on Solar Water Heaters

Another one that intrigues me is geothermal. Cost has to come down though.

yep, mostly the site work - the eqpt isnt altogether all that expensive, vs plain ole fashioned furnaces and a/c (split) units - (we wont even talk about the window stuff)

but note same on all the gee-whiz 'solutions'

but knowing a bit about the 2nd law thermo, the unique properties of phase changing substances, coupled with mass/volume etc
and methinks the heatpump strategy is the best way going forward - coupled with thermal mass/simple solar, off-peak rates (to time shift demand) some combo of battery and PV with some sort of self-contained backup for all the electro-mechanical nightmares,
and you essentially have a.....

boat.

;)

[Forrest]

Re: Doing the Math on Solar Water Heaters

It sounds like you know what you're doing. I admire your dedication to sustainable living. Wish I could do the same.

I don't know that I am all that dedicated to sustainable living, exactly...mostly I am becoming aware of more and more wasted everything. Somewhere we got used to cheap and disposable, and I don't think we're going to be living that way as much...it's such an expensive lifestyle.

For me, in a weird way, I don't mind the upfront investment to get my life running in a complete-bio cycle, because it's just so comfortable to the mind and spirit. It's primarily for safety in my rural area, where breakdowns in the grid are common...wind, lightening, car crash (a lot of those hitting important parts of the electrical system up and down the mountain). When you are going to be counting on keeping your plants alive in a desertish mountain area, you want your well always available, and the fridges, freezers & drying equipment going.

If I were working still, or didn't have the inheritance to work with, I would be leasing the equipment for the time being as they get better...battery breakthrough's should be coming as early as next year, what with the Stanford Zinc Air Battery research.

Did you calculate in the need to replace the batteries every 10 years or so?

As a doomer, I wonder about the cost and availability of batteries in the future . . . .

Yes, I know..me too, being a bit of a doomer myself, and not seeing much joy in the markets in the future, but I can only save money for the need, and hope that the product is continuing somewhere.

By the way, the new batteries coming on are completely drainable, so when the solar can attach to the grid, they just stay quiet, and unused, and hopefully not degrading.

I haven't done any in-depth study on this subject, so correct me if I'm wrong . . . .

If you are the only one creating the poop on your property, why are you concerned about disease?
As I understand it, the danger from human manure is that one can contract communicable diseases such as cholera and hepatitis. But unless someone who has these diseases is using your toilet, what is there to worry about?

Certainly, some sort of composting would be more convenient than just using a chamber pot and throwing the contents on the compost pile. But as far as health safety concerns, I think you may be going way overboard . . . .

What I'm saying would apply also for a healthy family.
However, if your plan is to regularly entertain guests from 3rd world countries, there may be a concern.

Actually, if it's just me, and a few visiting friends, I wouldn't be troubled about more than the Compost Toilet, and stirring that composted product it into my main compost pile with worms with added straw, grass, and clean soil, just to get a good compost mix, plus anything other leftovers/manures on the property.

Shiny however seemed worried, and if you are doing a large operation, you would have to do the sequential composting for maximum safety. On the other hand, with more people around to add to the problem, if they want to use my toilet, they have to help with the composting. Same thing with food...you want to eat, go weed something! Or get the chicken droppings to add to the compost heaps...or whatever. Or take the minitractor over to the horse ranch, and get some droppings out of the way for them.

[FrankL]

Re: Doing the Math on Solar Water Heaters

What about when you have friends over that are on medication, like antibiotics or anti-depressants? Do you intend to have a secondary toilet for them?

[Forrest]

Re: Doing the Math on Solar Water Heaters

What about when you have friends over that are on medication, like antibiotics or anti-depressants? Do you intend to have a secondary toilet for them?

I already have two standard toilets and a septic system...but I figure by the time I have too many people wanting to use my toilet that no one will have medicine anymore, and regardless, we'll have to have standard latrines that are continually dug, used covered, and extended, and hopefully not dug up by any animals. I will need to remember to get another bale of wire mesh to be held down by rocks...thanks for the idea.

[raja]

Re: Doing the Math on Solar Water Heaters

By the way, the new batteries coming on are completely drainable, so when the solar can attach to the grid, they just stay quiet, and unused, and hopefully not degrading.

Can you tell me a bit more about these new batteries?

I have a grid-tie solar setup . . . no batteries necessary. The util company pays me for the elec I generate-- cost of elec + 12 cents a kW. Much easier than actually trying to power my house with solar. No worries about a string of cloudy days, maxing out battery drainage by careless family members, and checking the SG.

However, what about if a big solar storm knocking out the gird? Scientists say 10 years of repair to get the grid back up . . . and that's if there's money to pay for it. What about a global financial collapse/derivatives crash? A super depression and the grid has the 3rd-world reliability of Haiti or Iraq (4 hours a day, if you're lucky). What about all the other natural and social disasters just waiting in the wings that would impair grid function?

So . . . I set up a minimal stand-alone solar power system that can use the existing roof panels.
Right now, the system is just trickle charging the batteries, but if the grid goes down or becomes inconsistent, I can just switch over to stand-alone mode.
The problem is that the batteries only last 10-12 years, even with a trickle charge setup.

I wanted to buy some batteries for backup, and just put them on the shelf. I was told they will degrade even when not used. Then I thought about buying dry batteries, and just adding the acid when I wanted to use them. But I was told the metals still degrade. I said, "What about if I store them in plastic wrap, so no air can get in, thereby preserving them?" The "experts" were skeptical; didn't know if that would work or not. Nobody had ever asked that question . . . .

I'd really like to find some sort of storable batteries that will work after 10 years of storage.
Any info on this would be appreciated . . . . .

[lektrode]

Re: Doing the Math on Solar Water Heaters

Can you tell me a bit more about these new batteries?

....
I'd really like to find some sort of storable batteries that will work after 10 years of storage.
Any info on this would be appreciated . . . . .

yes, please do forrest.

would seem that Li type would be the way to go - have some hitech.mil grade flashlites with Li batts that claim a 'min of 10yrs' storage life - they still working with batts from 2004(? mightve been 07, so not sure of that)

being an off-grid kinda guy (boats etc, plus some land clients) have also started looking into large banks of em - outfit from taiwan (with ofc in loswages) quoted me 16grand for 16kwh -
still perty pricey vs the AGM type tho: 16kwh / 12vdc = 5or6 x 8D size @ 600ea (or so appx 'wholesale') = 3grand vs 16 for the Li
but thats the only price quote i've solicited, so theres likely better deals to be had...

i rec/use AGM for offgrid since they dont self discharge like reg lead-acid, plus recharge 'easier' (req only 115% or so of dischg vs upwards of 135% on reg lead-acid = less eng run time on a boat or less PV/suntime on land)
but yeah, altho they'z pricey, they really are the way to go, once past the pain of scratching the check...
the only real drawback with em, is they need to be fully recharged on a freq/reg basis or their performance (# of cycles) will degrade quicker than reg lead-acid - so can be an issue for those that dont take care to make sure their charging regimen (capacity) is up to par.

am wondren if the auto batt packs (ala prius etc, TSLA ?) might be a better answer?

the other thing to consider, esp with stand-alone/offgrid apps is to try to keep demand/loads (the eqpt being run) directly on the battery voltage - read: DC appliances, refrig and lighting, pumps etc - so you DONT have to run the inverter unless you _need_ 120vac - as the inverter standby draw is, in a lot of units, enough to actually run a DC refrig - which tends to be the largest single draw.

any observations/comments/questions on any of this is most welcome.

[DSpencer]

Re: Doing the Math on Solar Water Heaters

I'd really like to find some sort of storable batteries that will work after 10 years of storage.
Any info on this would be appreciated . . . . .

I read about these a while ago and thought it was interesting for a cabin in the woods scenario. No idea if it would be practical.

http://en.wikipedia.org/wiki/Nickel%...93iron_battery

Edit: it appears that some companies are selling these for this type of purpose already. I also think it's possible to build your own.

[lektrode]

Re: Doing the Math on Solar Water Heaters

http://en.wikipedia.org/wiki/Nickel%...93iron_battery

The ability of these batteries to survive frequent cycling is due to the low solubility of the reactants in the electrolyte. The formation of metallic iron during charge is slow because of the low solubility of the ferrous hydroxide. While the slow formation of iron crystals preserves the electrodes, it also limits the high rate performance: these cells charge slowly, and are only able to discharge slowly.^[6] Nickel–iron cells should not be charged from a constant voltage supply since they can be damaged by thermal runaway; the cell internal voltage drops as gassing begins, raising temperature, which increases current drawn and so further increases gassing and temperature.

not so good for limited time (PV) charging?
not a problem for things like elec rail apps, where the wikiP mentions mostly used, since constant chg source would be available.

[Forrest]

Re: Doing the Math on Solar Water Heaters

Forrest,

Thank you very much for taking the time and effort to educate me on what you're doing.

I did have a couple more questions:

1) What does your electricity co-op charge you for transmission/distribution of electricity?

2) How many customers are in this co-op?

I ask because looking at PG & E level numbers isn't very helpful when trying to understand what actual transmission/distribution costs are - they factor in a lot of other things besides the out of pocket costs.

C1ue,

I gave the Co-op a call, and am waiting for them to get back to me...being a very small little business (maybe 10 workers, including the line men), it may take a little time for them to get me the information, but I told them why I wanted it, and I hope they will get back to me with what you need.

[Forrest]

Re: Doing the Math on Solar Water Heaters

Can you tell me a bit more about these new batteries?

I have a grid-tie solar setup . . . no batteries necessary. The util company pays me for the elec I generate-- cost of elec + 12 cents a kW. Much easier than actually trying to power my house with solar. No worries about a string of cloudy days, maxing out battery drainage by careless family members, and checking the SG.

However, what about if a big solar storm knocking out the gird? Scientists say 10 years of repair to get the grid back up . . . and that's if there's money to pay for it. What about a global financial collapse/derivatives crash? A super depression and the grid has the 3rd-world reliability of Haiti or Iraq (4 hours a day, if you're lucky). What about all the other natural and social disasters just waiting in the wings that would impair grid function?

So . . . I set up a minimal stand-alone solar power system that can use the existing roof panels.
Right now, the system is just trickle charging the batteries, but if the grid goes down or becomes inconsistent, I can just switch over to stand-alone mode.
The problem is that the batteries only last 10-12 years, even with a trickle charge setup.

I wanted to buy some batteries for backup, and just put them on the shelf. I was told they will degrade even when not used. Then I thought about buying dry batteries, and just adding the acid when I wanted to use them. But I was told the metals still degrade. I said, "What about if I store them in plastic wrap, so no air can get in, thereby preserving them?" The "experts" were skeptical; didn't know if that would work or not. Nobody had ever asked that question . . . .

I'd really like to find some sort of storable batteries that will work after 10 years of storage.
Any info on this would be appreciated . . . . .

I don't have that much info on them, except that they are a zinc nanotubes in parallel, seperated by small amounts of air. They will provide about 40% more than the Li-ion batteries as far as the current research shows, which is why I figure the Teslo company will be able to get really good batteries soon.

I heard about them from the contractor who was telling me to put off buying batteries for a year or two...but I can't run my system on a solar tie in if they go down without the battery backup.

And since my Co-op has had to cease all credits and payment for solar...their current contract, under their regulations within the State of California, are only permitted 5% of their contract to be replaced by solar energy. Since there was not enough to go around for the big agricultural people who were trying to grab the full 5%, and the little peons like me who want a guranateed supply of electricity in a rural area, they simply stopped the program for the time being. There is legislation sitting on Governor Jerry Brown's desk to change the situation, but even if it gets signed this year, they will near almost two years just to be able to re-negotiate their contract. He's a green freak, bless his stony little heart, but he has all those big utility monopolies, and the regular Solar Leaser's, which I think plan to give you the illusion of safety and cheap energy, but will merely be a profitable way to scam the average guy who thinks he will save money in the long run, when in reality, not owning their solar will keep them as much a debt slave as ever.

Evidently, under the current set-up at my Co-0p, there is no zeroing out, credits, or ability to for them to pay me the going rate for energy, so I have to keep my batteries full, as any amount not used by my fridges/freezers, water pump, pressure tanks, cooling the house, heating the house, heating coils in the soil in the greenhouse, plus fans, and lights, that is created by a solar installation will be wasted, as they will take it, but not be able to compensate or even credit me for it.

This not a good thing, but not something I am surprised at...nothing in my mountaintop valley is cheap to do in the beginning. As it was, only a rich rancher starting the Co-op in the mid 1950's gave us electricity at all by starting the Co-op. Before that was kerosene lamps, and windmill water generation, and only in the part of the valley where water is close to the surface. Once the Co-op was in, people spread out a lot, though the further you are away from a main line, the more you have to pay to have the lines brought in.

I am fortunate to have few really cloudy days out here, but it happens, so that is why I need both a tie-in to the Co-op, and the battery storage.

I know that I will probably have the marine batteries in the meantime, but I'll be keep my maintenance savings account high enough to change out batteries as they get old, and the new one's come on line. I have to be prepared to patch and repair my greenhouse just as I will need to patch and repair the house. When I build onto the house when the probate finishes a nuisance lawsuit, I will be able to do far more solar panels, and hope that there is a tie-in at that point for at least credits, although money sure would be nice!

[Forrest]

Re: Doing the Math on Solar Water Heaters

yes, please do forrest.

would seem that Li type would be the way to go - have some hitech.mil grade flashlites with Li batts that claim a 'min of 10yrs' storage life - they still working with batts from 2004(? mightve been 07, so not sure of that)

being an off-grid kinda guy (boats etc, plus some land clients) have also started looking into large banks of em - outfit from taiwan (with ofc in loswages) quoted me 16grand for 16kwh -
still perty pricey vs the AGM type tho: 16kwh / 12vdc = 5or6 x 8D size @ 600ea (or so appx 'wholesale') = 3grand vs 16 for the Li
but thats the only price quote i've solicited, so theres likely better deals to be had...

i rec/use AGM for offgrid since they dont self discharge like reg lead-acid, plus recharge 'easier' (req only 115% or so of dischg vs upwards of 135% on reg lead-acid = less eng run time on a boat or less PV/suntime on land)
but yeah, altho they'z pricey, they really are the way to go, once past the pain of scratching the check...
the only real drawback with em, is they need to be fully recharged on a freq/reg basis or their performance (# of cycles) will degrade quicker than reg lead-acid - so can be an issue for those that dont take care to make sure their charging regimen (capacity) is up to par.

am wondren if the auto batt packs (ala prius etc, TSLA ?) might be a better answer?

the other thing to consider, esp with stand-alone/offgrid apps is to try to keep demand/loads (the eqpt being run) directly on the battery voltage - read: DC appliances, refrig and lighting, pumps etc - so you DONT have to run the inverter unless you _need_ 120vac - as the inverter standby draw is, in a lot of units, enough to actually run a DC refrig - which tends to be the largest single draw.

any observations/comments/questions on any of this is most welcome.

I'll be happy to ask questions...I have three different contractors coming out, one Thursday, one Friday, and one on Monday. Just give me a list of questions I can print out.

By the way, how much voltage can I store for about $3000.00 - $5000.00?