Constructing Energy Efficient Dwellings

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AnGuy
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Constructing Energy Efficient Dwellings

Post by AnGuy »

I am curous what others have done to build energy efficient or self sufficient homes. If you built or retrofited your home, please do tell.
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Mike Veldman
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Re: Constructing Energy Efficient Dwellings

Post by Mike Veldman »

Mine is a retrofit. The house proper is 2700sqft brick vaneer frame construction. I have 12" of blown insulation in the attic, the attic has been vented so that it free flows to prevent heat build up in the warmer months. The heating system is solar hydronic, I converted the gas fired air handler with a water coil and feed it primarily with hot water from the solar collectors. In the evenings the hot water comes from a coil in my woodstove insert installed in the fireplace. I have no heat storage capibility in this system except the heated space itself. I had the gas turned off in 88 and have not needed it since. There is a passive solar input from the attached greenhouse and the attached sunroom in the daytime. Also from two humans and one KTU (kitty thermal unit). I do run resistive backup heat in the attached greenhouse because sombody else who lives in the house refuses to believe that the black plastic barrels of water keep it warm enough for her flowers. And, since I don't like it when the noise level goes up I have a space heater in the attached greenhouse on a thermostat. My 10'X10' greenhouse is detached and has six 12 gallon black plastic barrels against the south wall for backup heat, although I must admit the hydroponic fluids are mildly heated electrically when necessary. My primary electricity is grid based but I have a 900 amp/hour 12 volt battery bank charged by PV and wind generator. If we are without power I can plug into the inverter, otherwise the bank runs all the 12 volt radio equipment and some circulation pumps. I have installed automatic vent fans in places where heat builds up in the summer, like the laundry room, behind the refrigerator, the up right freezer, the pantry, the attached greenhouse and the sunroom plus I have a whole house fan that can draw in cool night air. All of the rooms in the house, lab, shop have ceiling fans for air circulation. The garage and the sunroom have hydronic coils in the slab which when once warmed with hot water temper the space well. I shade the brick and glass on the west side of the house with a combination of plantlife and crosshatch trellace to keep the bricks cooled in summer. I have a selectable damper and filter to recover the heat from the clothes dryer in winter. I have a gray water recovery system in which I collect, filter and recycle the water from the sinks, tub, shower and washing machine for plant water. I also capture rainwater. I have a 10 seer airconditioning system for the main house and have recently built a comparable heatpump for the sunroom with a hot gas recovery system to hopefully heat or preheat my domestic hot water, I have my hot water tank well insulated and on a timer programmed to our use habits. I've made plastic covers to seal the whole house and the automatic vent fans for the winter months. My heating and cooling systems do require some periodic human intervention for proper operation. I try to keep the house temp around 78 in the summer months and around 68 in the cooler ones, so far so good.

I have much greater plans for the new place I'm slowly building, but that's another story. I have small PV panels keeping the batteries on my generator, tractor, winch truck and 3/4ton truck, all of which reside at the new place alive. This has saved me a fortune on batteries. I just bought three more off of ebay for the jeep, minitruck and hamfest flyer (full sized van) here at the house, which are not frequently driven. And I almost forgot, I have panels for the his and hers garden tractors as well, I was never able to get more than one season from a garden tractor battery before PV, now I'm up to three sesons on these two batteries, that's $120 in batteries saved.

Sorry for the rambling, I wrote these down as I thought of them.

mike
I tried to contain myself, but I escaped.
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Richard Hull
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Re: Constructing Energy Efficient Dwellings

Post by Richard Hull »

In times of crisis and depravation, it can be the smallest of conveniences provided for by forethought that can provide rays of hope and a feeling that you were a bit ahead of the curve.

When hurricane Isabelle killed my power for 6 days, it was nice to have that big battery powering a simple overhead CCFL for area light and two 12v incandescent mini-floods for reading and both a radio and 5" TV for th' wifo. I caught up on a lot of reading then. My wife and I spent a lot of quality time together. I grilled out in the evenings and used the little coleman stove for simple small meals. The PV panel set up in the backyard restored the battery for the next night. The meats, milk and the like in the fridge (not much) were tossed out and meals were pretty much grilled cheese sandwiches, country ham, and canned vegatables for supper. (country ham needs no refrigeration). Bacon and eggs for breakfast

Nothing complicated, nothing fancy, just us and the three cats around the dining room table snoozing, reading, chatting, and the simple glow of that little B&W TV in my wife's face.

With 3/4 million people in the Richmond and surrounding counties without power, there were no generators to be found and few if any service stations that could pump the gas needed to run them. A boat load of minor accidents due to no traffic lights over the bulk of the city created gridlock at times. The few gas stations that had backup power for the pumps had 6 block lines to get gas. (More infrastructure issues that were only local)

A forced return to simpler things and simpler pleasures.

Fortunately, it was late summer and early fall and the temperatures while hot were not unbearable and all the windows in the house were thrown open to let the natural breeze blow through. A 12 volt fan was used by my wife to keep cool. and also blew air over our bed at night.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Brian McDermott
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Re: Constructing Energy Efficient Dwellings

Post by Brian McDermott »

Where does one actually buy the large PV cells that one would use to power a house?
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Richard Hull
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Re: Constructing Energy Efficient Dwellings

Post by Richard Hull »

Gee Whiz! Powering a whole house?! With normal housing using normal appliances and certainly at 120 volts, forget it. Such panels don't exist or are so far out there in price they are un-reachable.

Most totally solar electric homes run off DC that is battery based and are 12, 24, 48, or more volts. Photovoltaics recharge them during the day.

Such homes utilize smaller refrigerators than most any normal home owner would consider. They use lights that do not flood any and all rooms with intense light at night. Intense lighting is for desks, and work areas in the kitchen or office and is often spot lighted rather than area lighted. Vacuums and other applicances are also special and DC. Washers are also tiny compared to normal homes. Dryers are just not found and one uses nature with an old fashion clothes line. Hot water is most often supplied by roof mounted solar panels. Wood or coal or simple propane gas stoves run at minimal levels to keep the place at a little beolw normal room temperature during the winter. Such a total PV home would be totally powered up by a $2,500-$3,500, 2-3kw PV array. It might also have a 2kw inverter available on the buss for special uses should the need for 120v/60hz arise.

Such a home is usually smallish, incredibly well insulated, rather cramped, and would be no place to raise a normal 21st century family. By contrast, it would very cozy and very cheap and very efficient especially for the confirmed batchelor or a man with a barren wife who is 100% behind such a life style.

To actually photovoltaic normal 120 volt washers, dryers, water heaters, heat pumps, stoves, applicance of all sorts,etc in a modern dwelling with normal ceilings and fashionably large open areas is pretty much a fools errand. You would be best served to stay on the grid.

This is not to be flippant either.

Modern 20-30kw PV arrays charging the required massive battery bank running the most efficient 20kw inverters are in the $50,000 -100,000 class, installed.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Adam Szendrey
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Re: Constructing Energy Efficient Dwellings

Post by Adam Szendrey »

Holy cow...that's expensive. But a 20 kW array is way to much for us for example. We use somewhere between 250-300 kWh per month. I'm thinking of combining wind and solar. For solar i'm also thinking about stirling generators instead of PV. After all, a good stirling engine would be in the 20 % efficiency range (or more). A good insulation between the hot and the cold side (like a special piston tube made of two metal caps and cheramic between), would increase efficiency, also cooling the cold end by carrying away the unused heat would make things more efficient. It would be possible, to cover a large area with a heat collector material (i dunno, like a large matte black painted sheet of metal or something) and carry the heat from this large plate using heat pipes or some other heat carrier, or heat pumps, or whatever, to the hot end (so all the heat from the large surface area is concentrated to that hot end) of a well built stirling engine, attach a generator, and voila. I'm not sure about the efficiency of electric generators but i think it's rather good.
Also, another interesting idea is a solar turbine. I had this in mind for some time now. It's rather crazy. How about heating the compressed air in a turbine using solar energy, instead of burning propane, or whatever? The thing would blow really hot air, and while that, it could turn a generator or something (this is for stationary use ONLY ofcourse, as the heat collector would need to be large). Just some loose ideas.

Adam
Q
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Re: Constructing Energy Efficient Dwellings

Post by Q »

i have a small summer cabin that i am currently rebuilding. it was never intended to be lived in year round, but i have plans to change that.

for insulation the entire thing is constructed from 2.5 inch solid cedar. doesn't sound like much, but it works quite well. the biggest problem is the windows. i am replacing the original single pane windows with double pane well insulated ones.

for heat, i am currently using a high efficiency wood stove (catalytic "after burner"). i'm also constructing a solar hydronic heat system with an electric augmentation.

like adam, i plan to have both pv and wind generated electricity. this wont completely power my home, but will offset the bulk of my electricity use.

well, that's my $0.02 worth

Q
AnGuy
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Re: Constructing Energy Efficient Dwellings

Post by AnGuy »

> I converted the gas fired air handler with a water coil and feed it primarily with hot water from the solar collectors.

Mike, How hot does the water get from a solar collector, and how much volume can in produce in an hour at full sun during a fall or winter month? Also what are the dimensions of the solar collector(s)? I thought a two phase hot water system might be workable. The first phase would be a large hot water tank that is heated using solar collector, and then a standard tankless/on demand water heater to boost the temperature. Are there any decent Solar water manufacturers that offer vacuum insulated systems? Did you contruct your own? I assume that the hot water system you've set up runs on a closed loop system which uses antifreeze to deal with freezing temperatures. How are the pipes from the solar collectors insulated?

As far as PV systems go, I don't think the technology up to par yet. Mainly in the battery technology. Lead/Acid battery have a relatively short lifespan and also contain nasty chemicals. I see that some progress on flywheel batteries is occuring, but its probably 3 to 5 years before products are available that will integrate with PV systems. I am also concerned with PV panel lifespans. I read that if you can prevent the panels from over heating and its possible to limit degradation caused by microfractions from thermal cycling. I would imagine a water cooling system (using copper tubing on the back of the panel) might be affective, but that might be difficult to implement correctly and manage.

As far as cooling, I think a ground source system might work, but I would like to avoid using a heat pump. I would perfer to install a hot water baseboard heating system with a separate cooling system. This issue I think I am going to run into is finding an air conditioner exchanger that will work with cold water instead of freon. Since the water won't be as cold as the freon I think there will need to be more cooling surface in the exchanger. So I would probably need to modify it to get reasonable efficiently. One other concern is that torward the end of the season the ground source water temperate might rise too much to make effective cooling. It would be nice to have an exchanger that can use both a compressor and the ground source. Another alternative might be to modify a standard freon compressor to use a ground source water supply instead of using air for dumping the compressor heat load, but this is probably a lot less efficient than using the ground source directly.

For the ground source. I was thinking of drilling a group of 50 to 100 foot wells holes and place large diameter aluminum tubing. with a much smaller diameter PVC pipe to create a closed loop system. The aluminum tubing will be welded with a bottum plate. This might be cheaper than digging up a large area to install horizontal tubing, and should provide better coolling because of the depth. While open loop would be more thermally efficient a closed loop system has less maintance because of mineral buildup from the ground water. Athough, purchasing the aluminum tubing is probably going to cost a bundle, which might make this solution impractical.
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Mike Veldman
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Re: Constructing Energy Efficient Dwellings

Post by Mike Veldman »

My hot water collectors are commercially manufactured, I don't remember by whom, I'd have to go home and look at the plate on them. I have four 4'X8' collectors. The collectors are copper tubing in a header configuration with 6" wide copper fins bonded to the vertical riser pipes and 2" of high temperature fiberglass behind them. The solar loop is running a 50/50 water/antifreeze mix under 10psi positive pressure. The exit temperature for the circulating fluid has ranged as high as 250 degrees on a good sunny winters day. My system runs five individual circulation loops, a house loop to the air handler, a solar loop from the collectors, a fireplace loop from its heat extraction coil, and a back up boiler, which is an Amana commercial gas fired heating boiler. The Amanna has a 50gal propane bottle attached to it which has been refilled once since 1988, that's how little it's used. All of the loops with the exception of the house loop run the 50/50 mix, the house loop runs distilled water and circulates constantly as long as the measured temperature in the attic is below 35 degrees f. I did this because this loop travels over 40" of living space. Each of the feeder sources has its own heat exchanger in the house loop. The air handler is independently controlled, when the coil temp reaches 90 degrees the blower switches on and runs until the coil temp drops below 90 or the house temp reaches 68. At a house temp of 68 degrees the system shifts the hot water to the floor in the shop, the fifth loop. The backup boiler will only fire up if the house temp drops below 50 f. As a rule, the house temp will drop an average of 5 degrees over night.

This all started as an argument with one of my university professors in the 70s. The efficency of these systems is always measured against the bonnet temp of a gas or electric furnace which is 160 degrees f. I had and still subscribe to the belief that since the body begins to feel warmth at 90 f, that's the place to begin. My system brings the house up slowly using what was not normally considered useful heat.

The batteries in my pv system are commercial lead acid designed for ups service, I have had these batteries in service since 89. Mostly they see very little deep discharge, except for the yearly load test and equalizing charge. Last summers test pulled 1005 amps for 75 minutes before drop, this is a 950 amp/hour bank.

I have a bunch of stuff collected up to play with heat pumps but haven't yet. I'm planning to lay a ground source loop in below my lateral field as an experiment. Wells down here cost about a buck a foot plus casing. I also have a creek with constant water I want to play with for cooling. I have played with increasing the condenser size and cooling a block of ice at night, which was intern used to cool the house during the day. Worked, it'd be kind of expensive if you had to buy and maintain such a system. I also have an absorbsion airconditiong system and a 12' satellite dish I plan to use to provide the heat to fire it with. My prototype with a 5' dish and a camper fridge was a success, so I'm thinking bigger. I was able to get over 800 degree steam out of the five footer. I'd like to try some north facing solar type collectors to see how much cold I can extract from the night sky. Or, heat I can sink into the noght sky. I've purchased a windmill on a 30' tower I hope to try some heat pump experiments with, the wind blows here a lot and often so I'm thinking of running a freon compressor with it. Might even revisit my block of ice system.

I'll probably only need a couple more lifetimes to play with everything I'm interested in.

All of my alternative energy stuff is a hodge podge of commercial and home made adapted to my current use. I can fabricate and instrument about anything I have an interest in from my inventory, which continually grows because it follows my interests. The problem is, no project is ever completed in a contigious fasion. Too many toys, too little time. Not to mention the need to work for income to support my hobbies.

There are some pictures of my alternative energy projects at www.couger.com/mike

mike
I tried to contain myself, but I escaped.
3l
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Re: Constructing Energy Efficient Dwellings

Post by 3l »

Hi Guys:

I have found that the battery is not the key issue with the solar house but rather the inverter. I use 8 -115 amp hour trowling batteries from Walmart. By not discharging them too deeply
the life of the battery will extend for several years past the design lifetime. I have run my bank for 5 years so far with only minimal maintenece (adding distilled water). I have cut the cord to the power company entirely. My new 3kw inverter will run an intermittant loads like a washer,microwave,pulse fusor or gas dryer with ease. (I still use propane to heat with but it's days are numbered. I even mow my grass with a Black and Decker electric mower.
I only have 450 watts of panels with a 4kw windmill.
I have to bleed off excess charge in the spring and summer.
Cook meals in a small crock pot.
Costs so far around 4 k$
I use 12volt fans for ventilation....no fridge.

Happy fusoring!
Larry Leins
Fusor Tech
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Richard Hull
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Re: Constructing Energy Efficient Dwellings

Post by Richard Hull »

If one is OK with living a little more "spartan" existance, then a lot of real juice hungry accessories found in every home can be dispensed with. Fridge, washer, dryer, dish washer, etc. We all might be doing this all too soon.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
ijv
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Re: Constructing Energy Efficient Dwellings

Post by ijv »

I came across a cunning plan for a fridge that is claimed to use only 10% of the power of a conventional fridge recently.

What you do is take a chest freezer, the type with a lid on top, and simply modify its thremostat so that it stays above feezing (about 4°C).

The combination of good insulation and the fact that when you open the door from the top, the cold air stays in the fridge apparently give you power consumption that is only a tenth that of a conventional fridge.

You can use the baskets that come with these freezers to hold things that you regularly use and put stuff that you only occasionly use down the bottom.

Ivan Vuletich
ebeuerle
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Re: Constructing Energy Efficient Dwellings

Post by ebeuerle »

Here's a neat idea to make ice using solar power especially for those who really want to live off grid:
http://www.homepower.com/files/solarice.pdf
-Eddie B.
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Adam Szendrey
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Re: Constructing Energy Efficient Dwellings

Post by Adam Szendrey »

Really "cool" machine. Too bad it's so large.

Adam
Q
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Re: Constructing Energy Efficient Dwellings

Post by Q »

yeah, that is neat!
it's giving me ideas already.....

Q
ebeuerle
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Re: Constructing Energy Efficient Dwellings

Post by ebeuerle »

Yeah I recently came across that article and never thought of doing something like that with parabolic reflectors. It really is a great idea for those that live in hot arrid climates such as Africa and South America. But I am sure it would work most places as long as you have a decent amount of sun.
-Eddie B.
3l
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Re: Constructing Energy Efficient Dwellings

Post by 3l »

Hi Ricard:

You are right about being Spartan.
Use has to be watched like a hawk.
I had a young woman and her small sons visit me .
The kids left all the lights and tv on behind them.
Training for an energy frugallity is not a natural act it seems.
It only takes two days to put the batteries at top charge but only minutes to discharge it.

Happy Fusoring!
Larry Leins
Fusor Tech
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