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canadiannorthernhistorian

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Posts: 8
Reply with quote  #1 
My first post might be a lengthy one.

I built (or rather rebuilt) my first energy efficient house in 1973. I built my first passive solar house in Orillia Ontario in 1981. There was  lot of trail and error because heating contractors had no idea what I was up to and books were conflicting. We had no internet in those days. I surveyed sun angles with a transit and planned overhangs to let in winter sun but shade summer sun. We had wood heat as a supplement and electric heat as a backup if we were away for long periods. In the end a lot of my technology was redundant. The simplest system worked the best. The house would go for hours without going up a degree or down a degree. The system was designed to accommodate air conditioning but we never needed it.

We now live in a passive solar house that has neither a furnace nor an air conditioner just two fans. We wash our clothes and dishes in cold water. We have a gas stove and  gas/high efficiency European style on demand electric showers. Our electric use is confined to our two computers, a high efficiency refrigerator, those two fans, two water pumps, a TV, lighting and aqueponics.  The electric shower uses more energy but less water. However we have probably a year's supply of stored water (8000 US gallons) if we are careful. Last September we acquired an old upright freezer for free. That has increased our electric consumption dramatically. Still our consumption is less than 2400 Kwh/year, and less than $700 US, it was less than 2000 Kwh without the freezer. Not bad for a 3000 sq ft house, even in Brasil. At our age an expensive system might not pay for itself in our lifetime.

We just want independence from the grid. Power outages are a regular thing, and there is talk of electric rationing in Brasil because of drought and the dependence on hydro electric.

Initially we want just enough to run the hydroponics, one computer and the refrigerator. 

Wind power is not an option. We are in an urban area and don't have enough wind  speed anyway.

Our monthy sunshine varies from 4.8 hours/day to 8.5 hours/day with a 6.9 hour average. However, we are shaded on the west by office buildings, so it is necessary to deduct 40%.

Brasil doesn't offer incentives for solar electric power to the individual. The country has a lot of solar hot water, but we don't need that at present. Our hot water consumption is minimal and we are not dependent on electric power for hot water. There is a tax of 12% on imported solar technology.

Local prices are fairly competitive if you look around enough and bargain.  However we are willing/capable of building things ourselves.

We have calculated a rough size for an initial system, which would be designed to eventually go completely off grid. We also want something portable as the place is for sale and we would like to go to a better location (without those office buildings).

Mostly we need advice about batteries and inverters. We have considered converting our electric pumps to DC to avoid the start up load on the inverter. We have also considered a 12Vdc/120Vac/gas refrigerator to reduce the size of the system.

Our house is wired for the American 115v and the European 230v but we would probably get rid of our 230v appliances.

Canadiannorthernhistorian











GaryBIS

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Posts: 243
Reply with quote  #2 
Hi,
For the refrigerator, I would review the Energy Star listings and pick one of the more efficient ones.  
http://www.energystar.gov/index.cfm?fuseaction=find_a_product.showProductGroup&pgw_code=RF

http://www.builditsolar.com/Projects/SpaceHeating/DHWplusSpace/Main.htm

Regular 120VAC fridges have improved a lot in the last few years on energy efficiency -- you can probably find a full sized fridge that only uses about 300 KWH a year.

There are some sample small PV systems here: http://www.builditsolar.com/Projects/PV/pv.htm in the off-grid section -- they will give you and idea of what is involved.

You can use PVWatts to get an idea how much solar you can generate for a given size array, but you will have to account for your shading manually.

I'd recommend doing this simple site survey to make sure you fully understand the shading problem.
http://www.builditsolar.com/SiteSurvey/site_survey.htm

Gary






 
canadiannorthernhistorian

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Posts: 8
Reply with quote  #3 
Gary

Thank you for your quick response. You might wonder why we have an energy efficient house in the shade of office towers. The short answer to that is when the house was built the office towers weren't there.

We have already done the survey. With the shading, we can expect 3 useful hours of sunlight per day in December (rainy season) and 5 in July. For backup, we have to go with the 3. In the rainy season, we might go a week without direct sunshine, so we would be reduced to operating the aquaponics. We have never had a week without power to this point. We have had a couple of days.

We know what our total electric consumption is and in what months and we know the hours of sunshine and in what months but we don't know the consumption of individual appliances. The fridge was "energy efficient" when we bought it and undoubtedly came with a consumption guide but we can't find that. Our guess is 436 Kwh/year.

The acquaponics system is not more than 146 Kwh/year, but no power, no fish.

Again, we are concerned about the power loss through the inverter, and the power spikes of electric motors when they start. We are not sure what battery capacity to plan for since, at this point, the system would be just backup.

Our guess is we should plan for 2.26 Kwh/day. That is probably generous since our lowest month last year was 3.74 Kwh/day running everything except the freezer.

Ab (Canadiannorthernhistorian)



GaryBIS

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Posts: 243
Reply with quote  #4 
Hi,
Its probably worth getting a Kill-A-Watt meter so that you can measure the power consumption of your loads.

They are not very expensive: 
http://www.newegg.com/Product/Product.aspx?Item=82-715-001&ParentOnly=1&IsVirtualParent=1

This will also let you check for phantom loads -- that is, devices that use power even when they are off.  

Gary
canadiannorthernhistorian

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Posts: 8
Reply with quote  #5 
I am very happy I decided to join this site. The information supplied by Gary has been helpful, in this way: I checked out the site survey tools he sent us (which he seems to have put together himself) and they are superior to what I had devised for myself.

Often it helps to verbalize or write down your ideas for someone else even if that someone else has no idea what you are talking about.

That is what happened here. Now that I have everything straight in my head I think we can solve most problems on our own.

Our major problem is not shading. Our major problem is the rainy season. There can just be too many days in a row without sunshine to store enough power to enable solar electric to be a stand alone system.

Wind power is not an option.

But we have water. We have a large head for a turbine (over 30 ft) and -probably- a sufficient volume of water. Our water storage (enough for minimum 60 gallons a day during the dry season) only captures a small percent of the water we have available. When it rains, our hill is a small waterfall. That is what you get with tropical rain. We can run a small properly designed turbine to generate enough power to supplement stored solar power for our essential needs. There is no generator on the market capable of doing this to a worthwhile extent on the volume of water we have available, but I think I can make changes in the design myself for one that will.

So when we don't have sunshine we have potential water power, and when we don't have waterpower, we have more than adequate sun.

In any case, our potential buyer is coming tomorrow, so we might know if we have a sale, and what to look for in another site.

Ab (canadiannorthernhistorian)

Garage_Hermit

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Posts: 2,240
Reply with quote  #6 
"Often it helps to verbalize or write down your ideas for someone else even if that someone else has no idea what you are talking about."

Well said,
canadiannorthernhistorian !

Here are a couple of sites that might be of use, sorry that one is in French, U never know !

http://www.absak.com/library/hydro-power

http://www.birdenergy.fr/EnergieHydroelectrique.htm

Good luck with your future installation,

G_H


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solardan1959

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Posts: 1,845
Reply with quote  #7 
Thanks Hermit,
Interesting, if I had a good flowing stream or uphill source of water the AC/Grid-Tie 2kW Cross Flow Electrical Kit would be the way to go for good steady reliable power.
http://www.absak.com/catalog/product_info.php/cPath/33_89_91/products_id/1374
but there was some other neat ideas also.
Dan
Garage_Hermit

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Posts: 2,240
Reply with quote  #8 
Dan, maybe we should keep our voices down, this is not Strictly Solar ! ha ha !

G_H

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(1)  "Heat goes from hot to cold, there is no directional bias"
(2) It's wrote, "voilĂ " unless talking musical instruments...
canadiannorthernhistorian

Registered:
Posts: 8
Reply with quote  #9 
I don't see why combining solar with other renewable power sources is not a valid topic for this forum as long as solar IS involved.

My experience with 32 years of solar usage is that most systems are just too complex and involve too much power loss from their complexity as well as the need to eventually replace complex components and the risk of breakdown.

I have determined that, because of the long periods without sunshine, I need to reduce power losses as much as possible. Therefore, for the critical items I will convert to DC power to eliminate the power losses in the inverter, however "efficient" the AC appliances may be. It also gives me the option of using gas. I don't like to put all my eggs in one basket.

One of my many mottos is KISS which stands for Keep It Simple Stupid.

As I have already indicated we have the choice of heating our hot water (what little we use) with either gas or electricity.

For energy savings you should really consider washing your clothes and dishes in cold water. As I said before, we do. In addition, we wash our dishes by hand, for a further power savings. There are no streaks as those who would like to push the consumption of their energy would have you believe. We have an electric clothes dryer (also acquired for free) but we never use it. Clothes dried by natural sunlight and air feel and smell better anyway. The sun dries our dishes and clothes.

As to our water power, the only thing we really need a back up on, in the event of a lengthy grid failure and a long spell without sunshine is the pump on our acqueponics. Operating that pump by hand 24/7 would not only be unpleasant, it would be impossible. As long as we keep the density of fish in the system low, we don't need a mechanical aerator, as the system is designed to aerate itself just through the necessary water flow.

When I talk about constructing a more efficient turbine I am not suggesting that I can violate the laws of physics.

I would construct a turbine connected directly to the water pump on the tank by mechanical means. That eliminates complexity, reduces the risk of failure and reduces the draw on our batteries. It also eliminates the power losses of converting the mechanical energy of falling water to electrical energy. All I am left with is the friction in the bearings of the turbine and pump, which I would have anyway.

Ab (Canadiannorthernhistorian)
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