Doing the Math on Solar Water Heaters

[shiny!]

Re: Doing the Math on Solar Water Heaters

I'd say this comparison is probably not valid. Shiny lives in a mobile home, while you clearly do not since your monthly bill is at least twice what hers was prior to recent changes. I'm guessing your house is considerably larger than the 1100 square feet of a double wide.

Just for clarity, my home is a single wide with 756 sq. ft. using natural gas, not propane. The hot water heater is my only gas appliance. I don't know what propane would cost compared to natural gas.

Re: composting toilets:

Many years ago I lived with three other people in a dugout house that had a composting toilet. The slope for waste to descend had not been made steep enough. Consequently the waste backed up and had to be pushed down with a shovel. SO NOT FUN. I will never forget that smell. Make sure you build it right!

[Forrest]

Re: Doing the Math on Solar Water Heaters

[IMG]file:///C:\Users\Forrest\AppData\Local\Temp\msohtmlclip1\0 1\clip_image001.png[/IMG]Originally Posted by Forrest
C1ue, let’s look at the picture as I am looking at it.

I invest $35,000 at 2.9% interest, which generates an income of $1,015 per year. I will be paying 35% on that income in taxes, which leaves me a net yearly income on that investment of $659.75.

My electricity averages $300.00 month, as does the propane I use as I am not anywhere near natural gas facility, for a total of $600 per month, and $7200 per year. I will be able to replace my cost of propane by not using it for heating my house any longer, and will merely have to use propane for heating water and cooking until I install an electric water heater.

Ok, outline understood.
[IMG]file:///C:\Users\Forrest\AppData\Local\Temp\msohtmlclip1\0 1\clip_image001.png[/IMG]Originally Posted by Forrest
My monthly propane costs, except for heating water, and cooking with propane will be limited…I do not have the exact figure, but I will use Shiny’s estimate of her cost of $22.00 per month, or $264.00 per year.

I'd say this comparison is probably not valid. Shiny lives in a mobile home, while you clearly do not since your monthly bill is at least twice what hers was prior to recent changes. I'm guessing your house is considerably larger than the 1100 square feet of a double wide.

Actually, no. I have a double wide manufactured home…28’x40’. The differences here are the added high winds and humidity we have to battle in hot and cold weather. Cooling and dehumidifying costs more in the summer, as I am on the edges of the hurricanes that come up from Mexico in the summer, along with the coastal fogs; while during the winter we have to battle a lot of wind that strips the house of warmth. Propane supplied forced air heating is not as effective as radiant electric heat. The temperature swings daily are at least 40%, and even in winter, one often needs heat at night, then cooling during the day.

[IMG]file:///C:\Users\Forrest\AppData\Local\Temp\msohtmlclip1\0 1\clip_image001.png[/IMG]Originally Posted by Forrest
Taking the $7,200.00 minus $264.00 = $6,936.00 per year of non-taxable income to pay for the energy for my house.

How much actual electricity are you using? That's the real question. $35K of solar - presumably post rebate - is I'm guessing around 4 kW of installed capacity?

Approximately 4kW, without the added cost of heating and cooling a greenhouse that is bigger than my house is. That will required additional solar once I know the amount I draw from the electric company.

Having actual numbers is far more tenable than comparing solar install cost vs. your utilities bill(s) - because said bill(s) incorporate electricity, natural gas, transmission & distribution costs, taxes, and what not.

Cost is cost…it’s out of pocket money, and to me, part of the cost of living. Not having to pay those fees and taxes are a bonus.

As I've noted before - one of the ways by which solar feed-in customers free ride upon the rest of the population is that they don't pay their portion of the distribution and transmission costs, though I strongly suspect this will change soon.

Although I will be tied into the grid part of the time, when I am they will be using my excess electric production at no cost. My Electrical Co-operative is already limited on who gets to be paid for their electric, and I am outside that select group, and if I draw on energy I have credits for, I still have to pay for the distribution and transmission costs to get my own energy back.

Also, as a part owner of the Cooperative, I have a share in income and outgo...when you build where I am, you have to buy into the Electric Co-Operative.

Among other reasons, the feed-in process costs the utilities even more per kwh than just providing electricity downhill to customers - so the costs are being driven up even as those who are the cause of this are avoiding paying.

Alas, I am not able to avoid paying for moving any current anywhere, since I have to pay them to take my power, rather than the other way around. All I get are credits I can use rather than drawing on my battery backup system, which I have to have in the event of their shutdown.

I have to be able to go off the grid completely in order to just use my solar produced energy...when they lose power, they close a switch which makes me no longer attached to their grid, yet shut me down if I don't have an alternative supply. The batteries are expensive, but to even use solar when the sun is shining I have to have a completed circuit with some storage during any time the grid is down. The point is to have sufficient off-grid capacity to run my refrigerators and freezers, as well as pump the water.

I grew up with summers at a cabin without electric, water, or sanitation, and enjoyed it all. I can get through nights without light or electronics, and sanitation is easily taking care of if you have water, but I must have running water, which waters my food supply, as well as provides me something to drink., and wash in. I expect to get an electric water heater in time, but keep the gas water heater for emergencies.

[IMG]file:///C:\Users\Forrest\AppData\Local\Temp\msohtmlclip1\0 1\clip_image001.png[/IMG]Originally Posted by Forrest
To replace the expense of $6,936.00 at a 35% tax rate = $10,670 in taxable income. At 2.9%, I would need to invest $367,931 simply to pay for my energy costs at my house.
Instead, I invest $35,000, and at $7,200 per year, that makes my payback 4.86 years, without the rebate. Add to the fact that I will be pumping my own very clean water (Being up in the mountains there are less problems with dumping near my aquifer) at no cost, and providing water and some heat in winter for growing my own organic food in a well-equipped and insulated greenhouse, with electric coils to heat the soil, not the air, unless temps go below 17 degrees Fahrenheit, in which case, this first winter I will have to actually pay for a little electricity.

There seems to be a large gap here: grid access. Are you or are you not accessing electricity from the grid?

Both. On the Grid if it’s running, and off of the Grid when it is not.

From what you write above, it seems more like you're accumulating 'credits' due to the massive over-subsidy of feed-in tariffs and using this to offset your pre/post daylight and winter electricity costs.

I have pointed out numerous times just how regressive these feed-in tariffs are; if you are taking advantage of them, it is understandable, but you should keep in mind that ultimately all that's happening is that you're riding on the backs of everyone else who is still on the grid.

More importantly, as Spain and Germany are showing now, these outrageous feed-in tariffs can and will change over time.

Actually, as I have said above, I do not get these feed-in tariffs…my Electric Co-Operative is already maxed out on the amount allotted them under their contracts. So, there is very little parasitic behavior on my part at least. And again, I am a share owner of the Co-op...I will be happy to be rid of tarrifs...my small monthly profit would go up.

[IMG]file:///C:\Users\Forrest\AppData\Local\Temp\msohtmlclip1\0 1\clip_image001.png[/IMG]Originally Posted by Forrest
Next year, after testing the system, I will be expanding my solar array as needed to first cover any excess energy cost, and to provide for additional greenhouses.

My food costs will drop from about $1,000.00 per month, as organic vegetables are hideously expensive, to approximately half that, to buy clean meat from nearby growers, and the basic household goods that one doesn’t make or raise. If we set up a trading system, as is likely to happen as people retrench as times get more difficult, in my small rural town (1 small store, 2 gas stations, 1 farmer’s market, a hardware store, a couple of veterinarians, and one part time dentist, a Pharmacy, 10-15 churches, 4 small restaurants, a nursery, and a bakery) Otherwise I will be raising chickens as well, and growing their feed.

I get to have all of this from an initial $35,000.00 in solar. And I haven't even bothered to calculate the tax rebate on the system from State and Fed, as I will be using it to pay for battery storage during outages. I went high on my payback because of the batteries I will be buying...I don't have the figures yet for a setup that will keep my electricity flowing during daylight hours to calculate that in, so I am being very generous with my payback rate.

It won’t be perfect…there will additional expense for the battery backup for grid breakdowns which we do get already where I am at…heaven forfend a disaster down the mountain from where the local Electric Co-op taps into the grid. Wildfires take us down, high winds take us down, and I want also not to be hurt by a creakily aging electric grid very open to terrorist attack, or worse, a government shutoff from time to time just to let people know who’s in control. My house insurance will go up a little to cover the solar array, and I will have to have maintenance from time to time, as I do on everything.

And I can use the remainder of my little inheritance to invest in my land, and run a business producing high quality clean food. Or not…I might forgo the extra greenhouses, and invest in those beach houses at 14% interest…Mortgage Banking was my business, so I would at least know what I was doing. And then there is the gold play that I have a small stake in…who knows what the future will bring, but to have unencumbered land, house, greenhouse, solar array, well, and pumps without having to pay taxes or interest on the money to provide it makes it a very good bargain.

As I note above - there are quite a large number of assumptions implicit in your calculation of long term 'independence'.

Feed-in tariffs are one.

Again, not me, at least. And there is no such thing as independence in our world…never really has been. I want to have as low a cost as possible to live so that I can minimize my need for invested cash flow. There are no good investments that produce streams of income just now…and that is why I am reducing expense. And again, I am a share-owner in the Electric Co-Operative...it's required.

Cost of your labor is another. I think it is great to grow your own food, but most people who have regular jobs can't do that - at least nowhere near to the levels of self-sufficiency. A 'Victory Garden' type setup helps - particularly with fresh vegetables - but is a far, far cry from self-sufficiency.

In Russia, I have a lot of friends who spend a lot of time at their dachas (summer houses). They all put in potatoes, strawberries, cucumbers, herbs, tomatoes, and the like. However, they also all freely acknowledge that this is primarily a hobby. The small plots they have are nowhere near the capacity to feed even one family, and larger plots require large amounts of labor and machinery.

When you already raise things for fun, it is hard to look upon your labor as a cost, however, I have priced my labor into the savings for the clean food I will not have to purchase.
As for free time, I am not working. I am disabled/retired. What help I need I do pay for, however. And although I am on Social Security, I look upon that as a short term affair, and one that I paid into for a long time. Had the government had the decency to keep the money aside and invested it, as they were required to under the Social Security act, I would actually have a better monthly amount being given me. And my benefits were given me for a broken neck and brain damage, not just a sore back.

I use a walker…I’ll be in greenhouses because they have raised beds, that I can sit at to work in a protected climate, with the ability to raise food year round, something not really available at your average summer Dacha. They are much too cold to raise food year round unless they grow under lights hydroponically inside a building.

It really isn’t unusual to provide for a large family on 5 acres of good soil. Intensive gardening in greenhouse conditions allows me to get 4 times as much food from a protected planting area than out in the open, while out in the open, I will grow grains, and Sunflowers, to feed myself and my chickens. Yes, I will have crop loss due to rodents, which is why I have plenty of cats that I underfeed, and which consequently keep me almost rodent free. I fence out the rabbits, and smoke-bomb the gophers. The squirrels get trapped, and the coyotes are kept away by large dogs. And the excess food will be sold, or given away.

It really isn’t difficult to do…it merely requires a lot of knowledge, which I am grateful to have already; the money to set it up properly, which I have been blessed to have inherited; and the guts to do it.

A green thumb is helpful…but to me, that is merely patience and dedication to keep the plants going, growing, and protected from weather and pests, while feeding them as carefully as possible. And in a greenhouse, mechanical timers for everything are the key.

The plants are endowed by their Creator with the ability to grow…I don’t have to do that. And storing the food…if you harvest daily, you process a little at a time, and your day of checking everything, and processing the results is about 5 hours. I don’t keep cows, sheep, goats or horses…they are too expensive for a 1 person farm in both money and time.

I will have a small plant factory amid my chickens…it’s very common, and not difficult if you have already spent your life learning how to do it all. The rest is just sufficient investment for infrastructure and maintenance…just like a market economy.

[IMG]file:///C:\Users\Forrest\AppData\Local\Temp\msohtmlclip1\0 1\clip_image001.png[/IMG]Originally Posted by Forrest
As for hail, although I am in an upper mountain valley in Southern California, we rarely get hail...it's the mountains, sure, but it's also called high desert by a lot of weather people. And we get snow, but for rarely more than a few days, and at most 4-8 inches in a wet year, which we haven't been having lately. However, hail can be insured against. We are much more worried about high winds, and the Solar people are setting up for that, and again, I am insured.

Ah, so you're in a prime desert zone for solar - a nearly ideal area. Good for you.

I would note, however, that water access is probably non-trivial for a desert area.

Are you pipe or well?

I have a very good well on land where I own the water rights, with clean water, since nobody has been contaminating it, and very few people use it, because not everyone is suited to living in the middle of no-where. And with solar, I don’t have to worry about a lack of water due to a lack of electricity, which is why solar is a high priority.

My property is a little ecosystem…yes, I bring things in to make the soil better, but I also re-cycle all the waste product. After a few years of accumulation, you’d be surprised at how much compost builds up, and that from the part of the produce I don’t eat.

[IMG]file:///C:\Users\Forrest\AppData\Local\Temp\msohtmlclip1\0 1\clip_image001.png[/IMG]Originally Posted by Forrest
Yes, but we have 30 million illegal Mexicans/South Americans living here already that take very low pay in order to live here, and raise their kids where the schooling is terrible, but is better than none...a nice plantation aspect of the Corporate people in the State.

The illegal immigrants in the US get paid far more than their relatives back home.

Labor costs are still a big part of agriculture in areas like fruit and vegetables.

That may be changing - there is a lot of effort being put into mechanical harvesters for more delicate products. Time will tell how that goes.

Robots are always nice…when they can pick berries, and not bruise tomatoes, I will be impressed, and the laborer’s out of a job. When we get there will be interesting, but with a rising world population, we are going to need a lot of robots to raise the food, and that sounds expensive.

[IMG]file:///C:\Users\Forrest\AppData\Local\Temp\msohtmlclip1\0 1\clip_image001.png[/IMG]Originally Posted by Forrest
Yup...I actually plan to put in a composting toilet in my house...no need to waste the waste. But by bad ground water in other countries, I mean chemical dumps, factory waste in their streams and rivers, and a lot of pesticides that are illegal in the U.S. And then, there is a problem with really bad contamination and recalls of salad vegetables by sheer uncleanliness of the workers...we have a lot of problems with salmonella in our imported lettuce, celery, peppers, tomatoes and cucumbers. Using human waste for fertilizer is perfectly natural...but the bacteria is gotten rid of through the composting, and I sincerely doubt that anyone is going to be as careful about fertilizing my crops as I am. And fortunately, there is a lot of free fertilizer up here from racehorse breeders, ermine ranches, and of course, chickens.

While that's true - I have not seen any examples of chemical/pesticide type of foreign contamination getting into the US food supply. The primary examples I've seen are Salmonella type - and those aren't from the fertilizers. I wouldn't be surprised if these outbreaks are due to the human factor in harvesting.

I completely agree…it is a sanitation problem. However, like anything else, when it comes to the food I raise, as least I will know it is as safe as I can get it, with no chemicals involved on the food, and no hormones or antibiotics in the chickens and eggs. I also wash my hands. Add a little purchased grass fed/organically grain finished bison, beef and lamb, well, hopefully that will also encourage good health.

C1ue, I don’t think I will manage total independence…I am not really trying to. I merely want the best life I can have for the least money doing what I want to do, with the maximum of backup utilities, and the least amount of need for cash-flow in a world devoid of a safe interest rate.

It’s a way of life, not a whim…and if I weren’t already continuously moving toward more self–provision, I would have to be worrying about buying what grows freely of itself with just a bit of a helping hand.

Solar is merely a small part of what I am doing, but works very well with what I want to do with my time.

[Forrest]

Re: Doing the Math on Solar Water Heaters

Just for clarity, my home is a single wide with 756 sq. ft. using natural gas, not propane. The hot water heater is my only gas appliance. I don't know what propane would cost compared to natural gas.

Re: composting toilets:

Many years ago I lived with three other people in a dugout house that had a composting toilet. The slope for waste to descend had not been made steep enough. Consequently the waste backed up and had to be pushed down with a shovel. SO NOT FUN. I will never forget that smell. Make sure you build it right!

Yes..this can be very dangerous, and horrible to experience. It reminds me of the outhouse at our summer cabin...not my favorite thing. We used a propane toilet there after about 15 years...I didn't care for it.

The Composting toilet I am looking at is manufactured, and self contained, and since I live on a pretty good slope, I should have no problems. Thanks for re-inforcing the warnings already out there on this problem.

I want to use it because the idea of wasting usuable nutrients that plants like to use bothers me. After composting steer manure or horse manure, one wonders why people have such a horror of human manure. I suppose it comes from hundreds of years of putting their outhouse/drain field ABOVE their well, insead of below it, and less than a hundred feet away...all that unnecessary cholera!

I never was much of a green person...all my ideas are from Robert A. Heinlein's books...he thought them out very well. I am merely copying him. And I have a good many years experience in growing things. Some things I will be growing will simply be new to me, and therefore a lot of fun.

In fact, just trying to do this more or less self contained life is the sheer fun of it...it's a wonderful challenge to attempt, and then perfect.

[c1ue]

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.

[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.

I don't know either answer, C1ue, but I'll give the Co-Op a call on Monday, and see what I can find out...about both questions.

[shiny!]

Re: Doing the Math on Solar Water Heaters

Yes..this can be very dangerous, and horrible to experience. It reminds me of the outhouse at our summer cabin...not my favorite thing. We used a propane toilet there after about 15 years...I didn't care for it.

The Composting toilet I am looking at is manufactured, and self contained, and since I live on a pretty good slope, I should have no problems. Thanks for re-inforcing the warnings already out there on this problem.

I want to use it because the idea of wasting usuable nutrients that plants like to use bothers me. After composting steer manure or horse manure, one wonders why people have such a horror of human manure. I suppose it comes from hundreds of years of putting their outhouse/drain field ABOVE their well, insead of below it, and less than a hundred feet away...all that unnecessary cholera!

I never was much of a green person...all my ideas are from Robert A. Heinlein's books...he thought them out very well. I am merely copying him. And I have a good many years experience in growing things. Some things I will be growing will simply be new to me, and therefore a lot of fun.

In fact, just trying to do this more or less self contained life is the sheer fun of it...it's a wonderful challenge to attempt, and then perfect.

From the standpoint of pathogens, manure from herbivores like cows and horses is much safer than manure from meat-eaters like humans, cats and dogs. You can spread fresh herbivore manure directly over plants with the only risk being that you might burn the plants. I don't know if composting completely kills the pathogens in manure from meat-eaters, though. Some municipalities are successfully composting their sewage into fertilizer, but I wouldn't trust homemade human waste fertilizer without thorough testing.

[charliebrown]

Re: Doing the Math on Solar Water Heaters

Up here in the almost great white north, I need a lot of heat. The furnace starts running occasionally in September and is not off for the season until June. I was thinking ... about a windmill. A lot of the cost for wind is the conversion and storage of said energy, regulation and batteries. What if instead of storing the electricity you just heated water with it? The water stores the energy, no regulation or expensive storage devices needed. If you get more energy than needed to heat the water, just let it bleed off into the house, I need both the humidity and heat in the house. If you don't get enough heat, could it "boost" a conventional water heater. I live in a wind corridor. I think even a small windmill can produce a kilo watt of energy on most days for the better part of a day.

[Forrest]

Re: Doing the Math on Solar Water Heaters

From the standpoint of pathogens, manure from herbivores like cows and horses is much safer than manure from meat-eaters like humans, cats and dogs. You can spread fresh herbivore manure directly over plants with the only risk being that you might burn the plants. I don't know if composting completely kills the pathogens in manure from meat-eaters, though. Some municipalities are successfully composting their sewage into fertilizer, but I wouldn't trust homemade human waste fertilizer without thorough testing.

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).

Then one arranges for a protected area for the specific waste...it must be completely closed off from any animal interference...fine steel grid does it, and you only need about a 4'x10 foot enclosed strip. You line the grid with a thick tarp so as to not have the moistures leak out into the ground. Add already dried, partially composted waste from one of the new composting toilets, with about an equal amount of straw and green grass as the amount of manure, and a shovel full of clean earth. At this point the composted waste should not even be smelly, as you mix in the straw and grass. Build to a 2' height, mix thoroughly and water. Then cover with black 6-8 mil plastic, and re-enclose with top of the screen area. The heat from the sun aids in decomposition of manure, straw and green grass.

The amount of waste without the water is considerably reduced, so you only do a couple square feet at time. Check back each month to add water, or additional grass and straw. It can be left alone for a year, but stirring compost helps aureate it.

Once the manure smells like fresh, clean earth, it is usable, but I will add for additional value (and safety) to the compost at this point a pint of earthworms, and shade the portion under final treatment for a few months, checking occasionally for moisture content...earthworms cannot digest the straw and grass, as well as the other composted human waste without sufficient. It must be damp, but not wet, and as it is processed needs to be stirred occasionally.

At the end, I have the processed compost, with added composting materials, and some happy earthworms eating everything, and leaving me the worm castings that one never can get too much of.

Add the entire portion of finished compost, with worms, into topsoil. It's great stuff, and perfectly safe, and all the processes are natural, except for the small oven processing, which I would advise to kill anything in the soil.

The only danger from processing the human manure, after it is composted by the special toilet is handling it...one must be very careful to keep your hands well washed, as you would against salmonella and ecoli bacteria.

There is very little risk in this, but if you wanted to be extra careful, you would add the finished product to a winter crop planted for composted, putting one more series of composting into the mix. Then taking the finished crop, and chopping it, add all the soil, and the crop into a standard composting bin, and when fully composted again, it can be used as a top dressing for any plant with as much safety as anything you could want.

But if you wanted to have samples tested at that point, that’s what labs are for, until you are sure you are believe your processing is effective.

The process should take about a year for each new section...heat destroys the pathogens, just as it does for horse and cow manure, and pig manure is also a rich source of composting material if you can stand working with it...and they are omnivores just as we are.

[shiny!]

Re: Doing the Math on Solar Water Heaters

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

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

[c1ue]

Re: Doing the Math on Solar Water Heaters

Up here in the almost great white north, I need a lot of heat. The furnace starts running occasionally in September and is not off for the season until June. I was thinking ... about a windmill. A lot of the cost for wind is the conversion and storage of said energy, regulation and batteries. What if instead of storing the electricity you just heated water with it? The water stores the energy, no regulation or expensive storage devices needed. If you get more energy than needed to heat the water, just let it bleed off into the house, I need both the humidity and heat in the house. If you don't get enough heat, could it "boost" a conventional water heater. I live in a wind corridor. I think even a small windmill can produce a kilo watt of energy on most days for the better part of a day.

The problem is converting electricity to heat is extremely inefficient:

http://www.itulip.com/forums/showthr...tic-vs-thermal

One way to gauge how much electricity might be needed would be to look at the kwh consumption of your refrigerator.

[shiny!]

Re: Doing the Math on Solar Water Heaters

Up here in the almost great white north, I need a lot of heat. The furnace starts running occasionally in September and is not off for the season until June. I was thinking ... about a windmill. A lot of the cost for wind is the conversion and storage of said energy, regulation and batteries. What if instead of storing the electricity you just heated water with it? The water stores the energy, no regulation or expensive storage devices needed. If you get more energy than needed to heat the water, just let it bleed off into the house, I need both the humidity and heat in the house. If you don't get enough heat, could it "boost" a conventional water heater. I live in a wind corridor. I think even a small windmill can produce a kilo watt of energy on most days for the better part of a day.

I used to work for an architect who built a cabin off the grid in the mountains outside Santa Fe, NM. It gets very cold there in the winter, and cold at night even in the summer. He heated his cabin with a row of big water cylinder tanks that absorbed solar energy and slowly released it as heat.

Here's a link to Multi Tank Heat Storage.

[lektrode]

Re: Doing the Math on Solar Water Heaters

I used to work for an architect who built a cabin off the grid in the mountains outside Santa Fe, NM. It gets very cold there in the winter, and cold at night even in the summer. He heated his cabin with a row of big water cylinder tanks that absorbed solar energy and slowly released it as heat.

Here's a link to Multi Tank Heat Storage.

beat me to it, ms shiny!
can also do it with airflow directed thru rooftop panels and beneath the house and a thick bed of rock - the rock heats up all day long, then... well... you get the idea.

again - most of this stuff is NOT rocket science, has been done for decades and TA DA!!!

without _any_ multi-billion dollar subsidies (altho i'm sure the researcher/grant-writer types got plenty)

[lektrode]

Re: Doing the Math on Solar Water Heaters

The problem is converting electricity to heat is extremely inefficient:

http://www.itulip.com/forums/showthr...tic-vs-thermal

One way to gauge how much electricity might be needed would be to look at the kwh consumption of your refrigerator.

but there IS a way - assuming one isnt getting raped on the KWH's

based upon the COP of the basic refrigeration process or its latest acronymic regurgitation known as http://en.wikipedia.org/wiki/HSPF

simple explain of COP of refrig: put 1 KWH into simple resistive heating coil = 3412 BTU
put same KWH into a refrig process = 2 to 3x BTU, with upwards of 8 to 10x BTU's - now, apparently?

[c1ue]

Re: Doing the Math on Solar Water Heaters

but there IS a way - assuming one isnt getting raped on the KWH's

based upon the COP of the basic refrigeration process or its latest acronymic regurgitation known as http://en.wikipedia.org/wiki/HSPF

simple explain of COP of refrig: put 1 KWH into simple resistive heating coil = 3412 BTU
put same KWH into a refrig process = 2 to 3x BTU, with upwards of 8 to 10x BTU's - now, apparently?

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.

[raja]

Re: Doing the Math on Solar Water Heaters

I am getting quotes on solar to cover all my energy needs, and based on my average yearly cost, I will break even without any rebates or tax incentives in 8.3 years. On a system that will still be producing over 85% of the original power in 30 years, I think that it makes good sense for me, since I am in an rural area, and could just as easily go off grid a good deal of the time, and by switching to electric heaters for the winter, I won't have to pay the hideous propane bills except for the hot water and cooking.

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 . . . .