Designing for a Solar System

[Dimitri]

I was wondering if anyone purposly designed a house for solar electricity.  :question

I've been thinking about it, we get a few outages in the winter here.

I've been thinking for heating to use one of thouse wood heaters that you install out of the house and can burn little wood to heat up a house nicely. I'm thinking one that is for radiant heating would be best or one you could convert with alittle work to radiant.

Would rather not run off a generator if I dont have to so a off grid system like solar seems interesting.

Thoughts, suggestions, ideas ??

Dimitri

[Amanda_931]

Designing for passive Solar is probably a lot like designing for an underground house--the first try makes a lot of mistakes.  Somewhere there's an article by Dan Chiras? in Home Power? listing the 10 most common.

Unless you are using shingle style solar "panels," or even the yummy not quite on the market yet triple junction concentrating cells--some of which track automatically, there may not be much use in putting them on the roof--harder to clean off, and besides there's no tracking or seasonal changeability.  Although a roof is fine for hot water.  And that can be quite inexpensive if your idea of hot water is not over 100 degrees.

Unless you are resolutely staying away during the summer, a huge bank of south-facing glass may be overkill at least a quarter of the year.  Not to mention it gives you very very directional light, really bad if you have trash in your retinas.  I once lived in a house with super summer solar heating--during the hottest July on record.  

Although a good chunk of thermal mass can help prevent overheating.  And/or, you can put up awnings or have plants going up over pergolas to keep yourselves from frying in the summer.

Chiras warns about trying to do multipurpose greenhouses--although I do know some people who use their greenhouse both as a greenhouse (they sell vegetable plants, although rather quickly the plants outgrow that little space and move to a big greenhouse) and has a thermostatic blower to run 80+ degree (F) air into the rest of the house.  In the summer that little greenhouse is opened up as much as possible, and the blower is turned off.

Design will, to a large extent, mean daylighting, low power use in everything, insulation, compact fluorescent or (coming soon) LEDs.  If you live somewhere that there is summer, natural ventilation--e.g., cool tubes or equivalent is good.  Actually natural ventilation is good anyway.  Particularly if you didn't waterproof a concrete slab or walls.  

And common sense things, like don't put a big fireplace and chimney against an outside wall.

[Amanda_931]

Couldn't find the Chiras Home Power article, but here's Clarke Snell in a recent Mother Earth News.

http://www.motherearthnews.com/Green_Home_Building/2006_August_September/Go-Solar-and-Save-Big

Speaking of Mother Earth, the most recent cover article has a solar heater--elegant and simple, that the builder disables during the summer.  We got a preview a couple of months ago.

http://www.motherearthnews.com/alternative_energy/2006-12-01/Build-a-Simple-Solar-Heater

[glenn-k]

We have a member friend, Gary, with a solar website - check it out.

http://www.builditsolar.com/

[Dimitri]

Hello,

Thanks for the replys.  

Not so much looking into solar heating (a wood type outdoor funace will be the source of heat) but solar energy to power things around the house.

Going to have a bit of natural light in the house from the plan idea I got so far. Lighting wouldnt be the primary source of power use. Got alot more bigger things taking power I'd imagine (water heater, stove, water well, fridge etc).  

I figure if I am going to build a house and I've got a few years to prefect it I might as well do it right from the start.  8-)

Dimitri

[glenn-k]

Some of the things on your list are not done with solar - not practical.

Water heater and stove are nearly never done - they are big resistance loads doing little work for lots of power.  Energy efficient fridge and freezer are doable.  Microwave pulls a lot of power but for a short time.  Water well can be done - best with direct pump off panels - I use a normal 220v pump but system must be large to do it.  Even at that, I don't have a lot of excess capacity for pumping but do pretty good.

Cookstove and water heater are best done with propane.  Heat-- oil or propane - best is probably wood if you have your own wood supply.

Resistance loads such as heaters or electric stoves eat way too much solar power.

[Amanda_931]

Gary of BuildItSolar is the author of the Mother's article.

And if he's right (not too big a reliance, for instance on salvaged or already acquired items), then up North, he has about a one-year payback for his system.

That's basically amazing.  And worth thinking about for almost anywhere--barn or house or shop.

I think that if all you want is solar electricity all you have to do is stick a pole in the ground for panels (or the by then available triple junction cells with built-in tracking) have a battery shed, vented, and a place for your gauges and switches as close as possible to both.

But, especially at the moment, solar panels are expensive.  Demand is great, lots of countries have rebates or allowances for installing them, which means that the price is not as big a part of the "can we afford it" as it used to be, at least in this country.

So the big deal is to get what you need without breaking the bank.  Flat out low energy use.  

And as I said earlier, not-really-hot hot water, solar style, is pretty easy.  Doug Kalmer has done it for over 20 years.

This isn't the best article--but he's written this up a bunch of places--Countryside, etc, he has a slide show for his second system (in the barn/studio), somewhere, complete with wiring diagrams.

The point is that all those systems from the 70's were very inefficient.  You did not get your working fluid to near water's boiling point.  And so a lot of people who had them then have let them sit in the yard or garage.  He was certainly finding them as late as two years ago.

http://www.solarfacts.net/articles/diy/diy_solar_hot_water_heater_-_doug_kalmer.html

And an earlier description of Doug's system

http://www.countrysidemag.com/issues/1_2001.htm#water

[MountainDon]

Glenn is bang on with his reccommedations that you should NOT try to do cooking and water heating (resistance loads = using electricity to produce heat). Lighting is much easier, IF you use compact fluorescent lamps. You get a lot of light for small amounts of power; can even get then in 12 VDC if your doing a very small space. Best to figure going bigger and starting with an adequate sized battery pack and use good stackable inverters. (You will always want more power; stackable inverters allow you to grow your AC power supply.) As for the batteries, be careful to honestly assess your power needs as it's not advisable to increase the size of the battery pack down the road. Batteries can be real finicky and don't like new kids on the block to be joined into the old gang.

I'm assuming you don't care to connect to the grid at all. Right??

You said you get outages in the winter. How long do they last; worst case?? If they're not too long you could connect to the grid if it's avaiulable, cost effective and get away with a smaller battery pack... it would just be needed to cover the emergency. Then if you have a large enough PV array you be selling your power back to the utility company when the sun shines, pay them when it doesn't, and use your backup batteries when something goes wrong with the grid.

A generator is always handy, but remember they like it best to be run every so often. IF you are not on the grid you'd want/need a generator to be sure to have enough power available to charge the batteries with what's called an equalization charge. If you're grid tied you can use the power company's power for that.

After heating appliances refrigerators are the biggest power consumer. A new, energy efficient Kenmore, whatever are workable but the Sunfrost are the better/best way to go. That's more important if you're trying to be energy self sufficent. Depending on the fridge you can add insulation to the sides, top, even the back maybe and cut the power use. Standing infront of the fridge with the door open while you decide what looks good for that snack is a no-no.

You really need to do an energy audit to see how much power you will use. Be generous in your assumptions. I now need more pwerful lamps to read by than I did when I was younger.

[glenn-k]

You got the more power right, Mountain Don.  I'm pretty happy with my stacked Trace Sine 4024's .

You got the more light to read right too.  Where'd those fuzzy letters come from - worse when I'm burned out but reading glasses once in a while take care of it -- or longer arms. :-?

[desdawg]

I guess if you are going to do it right you start with the basics such as orientation of the home on the property, proper overhangs at the eaves to block the summer sun but allow it in the winter, a solar mass wall to absorb the heat from the winter sun and release it throughout the night, etc. etc. etc. I think there is quite a bit to it if you do the entire passive solar package. I have never really studied all of it that thoroughly.
Some people have enough wind to use a combination of sun and wind for generation of electricity. I put my little house down over a ridge so I don't qualify. I did buy a small wind genny but I have never put it up. There are many factors to consider so if you have time now before you get started and if you have a piece of land that will allow proper orientation you can design something that is very efficient. Many times the property will have other features that make the solar orientation of the home less than desireable.
I looked briefly at the outdoor furnace concept and from what I remember most were water heaters. They required pumps to circulate the heated water and, if you use a heat exchanger, fans to distribute the heat. And they were pretty pricey. With an indoor wood stove you can heat your space without using electricity. And since heating happens in the winter when there is less sunshine .......being off grid I didn't pursue it. These are just some thoughts from my limited forays into these areas.

[Amanda_931]

The most seriously green people I know bought a place up in the next county, off-grid, with radiant heating in what was originally built as a garage/shop.  Fired by an outdoor boiler.

The last time I was up there they were burning 4x4 and railroad tie off-cuts (pre-pressurization treatment), that they had to pay for, something like $70 a pickup truck load.   People do gather sawmill rejects, presumably for firewood, from a few miles south of them, but they tend to be mostly bark, which I gather doesn't burn as well.  

Furthermore, they had to go outside to fire the thing up.  It didn't like a small fire.  It seemed to be burning with not much smoke, although there were soot stains on the chimney.  And the radiant system was sized for the garage/shop, not the house it had been converted to.  The choice was overheat a lot, then let the thermal mass spiral the temperature down to comfortable, or do without.  She of the couple, at least, was pretty annoyed with it.    Enough that they had moved their bed outside to use at least until the temperature got below the mid-twenties.

Some of the radiant heat problems could have been avoided if they had built rather than inherited the system.  Not all of them.

What Glenn's building now would probably be easier to use with smallish branches, as well as longish pieces of split wood, stuff you could gather, rather than buy or have to make a big deal out of cutting every year. (the couple in the next county does have 10 or 20 acres of young hardwood, not enough biggish stuff to be worth cutting for firewood, probably fine for a rocket stove).  

There's a picture of Ianto Evans sitting next to his with his teacup on the top of the really hot part.  He couldn't do that while the fire was burning.

[glenn-k]

One of the reasons for the proliferation of outdoor boilers was to get away from air quality issues I heard.  Not that they were desirable, economical or easy to operate.  Some of the laws don't apply to them outside.  I would not want to go out to stoke the fire.  That's why I put the primer hole inside on the rocket stove.  It could have gone outside.  The rocket stove can burn wood around 4"x4" x 3' if desired - the opening on mine is 6" by 8".  Scrap lumber works pretty decent.

[littlegirlgo]

I am designing my building with the intent of being totally off grid. I will use propane for a cookstove and a small heater. Passive solar for heating and cooling are part of the design as is energy conservation. I plan to use a wood stove for backup and a small vented propane heater for when I am away overnight in winter. One of the nice things about solar is it can be done in sections. I plan to install solar in three "sections" starting with DC loads for lights and refridge. My total cost estimate is $7200 for a 1KW system and also includes hot water. It will pay for itself in 6 - 7 years if I figure in the several thousand to hook up to grid and monthly bill savings. I called the power company and asked about hook up charges and average monthly billing. I recently wrote a paper for school on solar and the prices are definatley coming down. Also if you DIY you can save a lot on system costs and watch for sales at some of the big retailers. I suggest you hook up with your local or state solar group. I have made wonderful contacts this way, visited many homes ect. I also have several Amish friends which are invaluable resources. Some resources I like are:

Countryside mag has some good solar articles
http://www.countrysidemag.com/past.htm

I like Rex Ewings books Power with Nature and Got Sun Get Solar
http://www.pixyjackpress.com/

[glenn-k]

That's the way to do it, littlegirlgo.

[littlegirlgo]

I forgot to mention incentives being offered by the federal government and many states for the purchase of renewables. Check the incentive program carefully, sometimes it is only for new equipement, sometimes it requires a professional CEM to look over.

http://www.dsireusa.org/index.cfm

[glenn-k]

CA requires you to hook to the grid to receive the benefit thereby subjecting you to annual taxation and negating any supposed benefit except helping their buddies at the power company keep from having to fight tree huggers to expand.  CA rules are set so that you can trade out what you make (net metering)  but if you make extra it is bought from you at avoided cost - a minuscule amount paid by their power company buddies shafting you out of your investment as usual.

I always look at it as   they have to take it from you before they can give anything to you -- minus administration fees which usually amount to over 80%.

I got the bad attitude - I know--  

Note that as littlegirlgo says, though - she is right -- you may be able to benefit in the right situation.

[MountainDon]

More often than not there's a catch of some kind buried in the fine print. Here in NM you must be grid tied for the credits, as well they have a selected list of qualifying equipment. Also if you have any sort of backup you probably will not qualify for the credits. NM also uses the avoided cost thing to avoid paying you any real money. Still if you size your system just right, not too big, you can save a good amount each month.

[Dimitri]

Thanks for all the replies,

When I do get around to building my house the location I really want to live in must lose power alot. This past spring some areas lost power for over a month with a bad rain storm they had as one example.   The winter has been mild this year. Heck parts of Ontario had their first green Christmas in decades. I've never had one before this year.  

I'm not into green energy, not one bit, the enviroment isn't my top consern with wanting to go solar, having power at my house so once I start a family I never have to worry about storms causing problems is the main reason. A guy has to keep his family safe and happy after all.

I've been looking over solar/battery systems, I wonder if its possible to have a system which will run everything or atleast almost everything. Maybe hook up the fridge and water heater to Natural gas thats fine with me.

Dimitri

[MountainDon]

It's usually possible to have anything you want; just a degree of how much money you want to or can afford to throw at it.  

As was stated before, anything to do with making something warmer should be done with something other than electricity IF the electricity is originating at a PV array, or batteries.

A solar powered off grid system can be set up using a good quality energy conserving fridge, depending upon your "insolation" factor, batteries..... Paying more for a Sunfrost may be the wiser long range solution. How long do you plan to stay in the place? Sunfrosts seem to run forever.

Best to shop around for expert advice and compare. I really like the people guy at  www.thesolar.biz

[Amanda_931]

Maybe the first thing to do to start out designing for a solar system is to look at the maps.  What geographic areas have the most probability for full-time solar, no generator or nothing.

Most of us decide where for other reasons--close to friends and family, we've always loved the area, it was inexpensive, etc.

We've posted some maps here recently--here's a world map showing the worst month of the year.

http://www.sunwize.com/info_center/insolmap.htm

[Amanda_931]

Here's another with the emphasis on Canada.

http://www.rpco.com/products/solar/solar_uscanada.htm

Looks like thinking about wind or water sounds good.

Water's generally the hardest to come by, but if you've got it it can be very inexpensive indeed.

With wind, I gather that the tower is the most expensive part, unless your scrounging and putting away properties are good.

[glenn-k]

I built my own tower for about $200 worth of cable and clamps, scrap steel and old 4" thinwall pipe I had left from well drilling.  A bit of cutting and welding and it was ready to go.

[Amanda_931]

True.  Your scrounging and saving skills are very good indeed.

[waywar]

Hello, new here.  I read an interesting book on passive solar design some years ago called "The Passive Solar House," by James Kachadorian.  It offered a wealth of information on passive solar design.  Over the past several years I have designed energy efficient vacation homes and permanent residences utilizing both solar and wind generated alternative power.  Lately, I have been bombarded with emails requesting information on solar power.  Solar power is becoming more cost effective.  There are a multitude of suppliers and vendors selling the equipment to power your home on or off grid.  One way is to figure out which supplier you want to use, then get a detailed drawing or schematic of their layout and discuss the building with your designer or architect.  They will greatly appreciate your efforts and save you some money.  Once they have the information they can layout your system in conjunction with your floorplans.  Today, green building is becoming more mainstream and energy efficient homes are definately on the rise.  The thing about passive solar design is that it really works if done properly.  You can have an extremely nice design and all the comforts of a conventional home.  Utilizing passive solar layouts, solar power, wind power, solar walls, a super insulated building and the latest green building techniques you can construct a solid energy efficient, environmentally sound home.  I know, a real mouthful!  But, believe me, it works!  
Thank you,  Wayne
http://www.waynedesign.net
warnerwayne@bellsouth.net

[Dimitri]

Mountain Don,

I've moved around too much in my life already once I build this dream house of mine its the last stop hopefully.

Dimitri