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Ask Jeff Yago
Solar & Energy-Related Issues

By Jeffrey Yago, P.E., CEM
Jeff Yago

Recycling power poles

Jeff:

I'm in Georgia and Georgia Power is redoing the lines with massive new metal poles. Do you know how I can get some old wooden ones. I want to build a barn.

Sandra Fowler

Sandra:

Usually when they replace a line of power poles, they leave the old wooden poles on the ground for several days until they can send a truck to pick them up. Years ago you could ask this pick-up crew to just leave any poles that were on your property and they would. With so much recycling going on these days, the power company they may contract all pole removal to private companies that recycle these poles for re-sale, so I do not know how pleased they would be to give them away but it does not hurt to ask.

Jeff Yago


Simulating a grid on a grid tied system

Jeff,

I have a Fronius 5100 inverter on a grid tied solar system. When the grid goes down, I lose all power to my house even though the solar panels are working.

Is there a way to simulate the grid so that when power goes down I can still utilize my solar energy?

Thanks

Mike Emmons

Mike:

I can't believe this was a surprise to you, and I sincerely hope the installer made it very clear that ALL grid-tie solar inverters are designed to shut down in the event of the loss of grid power.

If they continued to operate after a power outage, they could be energizing a downed power line that the utility crew would not realize power was being supplied from the wrong end of the line which they may not check. Keep in mind that any power you are sending back to the grid at 240 volts AC goes through the transformer on the power pole in reverse and will go out onto the power lines at 480 or higher voltage which is deadly.

All inverters must pass a very strict testing process to make sure their design will not allow this to happen, and proof of meeting this safety requirement must be provided to the local utility before they will allow you to install the inverter on their grid. The equipment label will note - "UL 1741" and "IEEE 929" to indicate this.

Yes, there is a way to make a grid-tie inverter "think" the grid is still operating and not shut down, but this requires a second inverter with battery backup. In addition, since the first inverter is now being fooled and continues to operate, your system must isolate the output from the utility grid, and include enough electrical loads in your home that are operating to consume this excess power being generated or you will have a system error in the inverter that will shut the system down.

I do not want to give out too much information on this subject as you really need to work with an experienced solar installer to make this conversion due to several safety concerns, but it can be done.

Good Luck,

Jeff Yago


Steam generator

Hi Jeff,

We are looking for a small, residential use steam turbine generator. We are having difficulties finding a supplier. Could you help us out?

Chuck Butcher
Canada

Chuck:

Due to the requirement for lots of daily maintenance, oiling, and adjustment, most of these small residential-size steam generators are do-it-yourself kits or home-made. Here are some links to get you started.

Many years ago I owned a steam powered generator that was new surplus intended to provide standby power for ships with fired boilers. I can tell you that this thing was big and weighed over 6000 pounds, yet it was only rated for 25 HP, or about the power of a twin cylinder commercial lawn-mower. Unless you are operating a high pressure boiler which can be very dangerous if not properly tested and operated, it takes a very large steam engine to produce any power with low pressure steam, which is most likely what your boiler will produce. Also note that most states require any steam boiler to have a safety inspection every year or two, and all pressure relief valves must be certified.

Assuming you can provide all of the above, any steam boiler requires high quality makeup water to reduce sediment buildup inside the boiler and piping, and most steam boilers must have their "mud-drum blown down" each day by an operator to get rid of this buildup. Also, this makeup water must be tested on a regular basis to determine what chemicals are needed to be added to get rid of any scale and mineral deposits in the system.

If you want a reality check, fill a large pan with tap water, then put on the stove and heat to boiling. Let it boil until all of the water has boiled off, then look what is stuck to the bottom of the pan. These mineral deposits are building up day after day in any steam system and must be controlled.

My advice, if you want to build a hobby steam engine then go for it, but I think you will find the day-to-day operation of a real steam driven generator to be a full time job.

Good luck,

Jeff Yago


We want to build a low carbon footprint home

Jeff,

I am reading through your BHM archives looking for rules of thumb to develop my plans for my last single family home.

I've been to look at solar and the formulas they use have more than one ridiculous assumption - i.e. the tax bracket is 40% and that electricity will inflate at an average of 3.8% forever (ours hasn't here in ga.) and that the house will increase in value 25% of the total cost of project and the house will appreciate at 6% over the next 30 years ( i'm not wanting to take more of your time, just trying to convince you I am putting in my homework and trying to be functionally literate)

I don't particularly like the looks of the solar homes I have found on the web.

I am not really willing to take 2 min showers and go with the flushless composting comode.

I do want a cistern, backup propane, plan ready for when solar really becomes almost reasonable, energy efficient refrig, non glowplug gas oven. I think I can get our electric use down to around max at any given time under 3500 watts if what is said about concrete walls and roof and proper sizing of HVAC cuts those two elements to a third and oh yea a solar hot water heater.

I haven't bought the land yet and I am looking for an architect that has experience and references designing and orchestrating the building of low carbon footprint homes ( know anyone in the Atlanta area). I know about southface here in town and leed and earthcraft stickbuilt guidelines (but I don't want a stickbuilt)

Hope you have time to respond

Tony

Tony:

I am not sure what you want me to say. You have listed several areas that will reduce your energy requirements which is a good first step. The "rule of thumb" finance advice you are finding is a joke and a total waste of time. The last page of my earlier book titled Achieving Energy Independence - One Step at a Time (now out of print) had a solar system sizing chart. You start with the number of solar modules you can afford and then the chart will tell you how much energy the system will produce.

The reason for working backwards is that I spent years making very detailed computer models and engineering analysis on each solar-power system I designed to determine what system size would be required for the given loads. I always was then told by the client after doing all this analysis that they could not afford a system that large. Finally I just asked how much they were willing to spend then I designed the best system I could for their given budget, and at least I know they will consume all the solar power their system will generate without being over-sized!

Keep in mind that if you purchase a quality inverter that is large enough to also handle future loads, you can always install only part of the solar array at first to keep costs down, and add more modules later since these represent the highest cost items in the system. You will use what you generate and rely on the utility grid or a generator to make up any difference until you can enlarge the solar array.

Good Luck,

Jeff Yago


Windpower

Jeff:

Since there is a problem converting wind to electricity directly, why not use the wind power to pump water up to a storage tank? The water can then be drawn off as needed, run past a turbine connected to a generator, collected at the bottom and pumped back into the tank.

Jim Whitman

Jim:

There is no problem converting wind power into electricity. Several companies make off-the-shelf inverters designed specifically for converting the power from a wind turbine into grid electric power.

Here in Virginia, Virginia Power has a pumped storage power facility that is very big. During the night when electric demand is low, they operate very large pumps to pump water up to a large water storage "lake" high above on a mountain. Then during those times when the demand on the electric grid exceeds their on line generating capacity, they open the valves and the motor-driven pumps operate in reverse and generate electricity. The system is very useful since it can start producing power minutes after the valves are opened, but it can only operate a few hours due to the very fast discharge required. The real drawback is this type system is very in-efficient and requires far more power to pump then it generates, but this is acceptable since it avoids having to start other generating plants which takes hours or even days to get up to full operation.

Here is a link if you want to know more about this technology:

http://www.dom.com/about/stations/hydro/bath.jsp

Good luck,

Jeff Yago


RV solar system

I am trying to duplicate your RV solar system. (Good article)

I can not find a source for a Siemens 100-watt 12-volt panel. In fact I am having trouble finding any 100 Watt panel.

I need a 21 inch high panel rather than a 26 inch high panel and there seems to be a size break around 100 Watts.

Is there a great deal of difference in the quality between makers of panels or is a dollar/watt computation that I should use in choosing a panel - and take the lowest one?

Dave Little

Dave:

Until going to the recent solar dealer convention in Long Beach several weeks ago, I would have said that most solar modules were made almost the same and had the same high quality. These better manufacturers include SolarWorld (was Siemens, then Shell) , Evergreen Solar, Mitsubishi, Kyocera, Uni-Solar, Sharp, GE, and Sanyo. I have used them all and they all appear to be almost identical except for physical size and frame design. However, at this recent convention I found hundreds of different brands and sizes of solar modules that are just now being manufactured and shipped from China. I have recently used some Suntech Power modules which are made in China and these appear to be very well made, but I believe the Suntech company has been making solar modules for years and has their act together. However, many of the other Chinese manufacturers are fairly new and their modules may have problems that may not show up until after they have been installed.

I suggest staying with the brands I suggested until the overseas market shakes out. You will find module prices hard to compare unless you convert each module cost into $ per sq. ft. This is the best way to comparison shop and all module brands will be cheaper in the larger wattage sizes. Several years ago modules were selling for $12.00 per watt, today you will find retail prices for U.S. made modules in the $8.00 to $10.00 per sq. ft. range, depending on order size. Modules made in China are currently selling below these prices.

Good luck,

Jeff Yago


Small water boiler

Jeff:

Great web site.

It's great seeing what other people are up too and knowing that you are a bunch of people trying to make the world a better place too. We both live in incredible time Hey? :)

Well I am wondering if you know how to make a small water boiler, one that would boil an egg. For example maybe a jar painted black with the lid on and egg inside. I have tried this before, it took quite a while........

Anyway :), just wondering if you have any ideas or information on those kinds of home made water boilers.

Hey, thank you so much, G's your gorgeous

Naomi

Naomi:

Haven't heard the egg in the jar and really doubt that it works. The problem is you need to increase the temperature of the sun's rays falling on any surface, and the only way to do that is to concentrate a large area of sunlight onto a smaller area, like a magnifying glass operates.

Most homemade solar cookers have a large area of reflector surface area around a small cooking area that reflects sunlight back onto this smaller area which increases the temperature. If you want to stay with your boiling egg in the jar system, use a jar that is rated for heating and place all but the top of the jar down in an insulated larger coffee can. Make cardboard or plywood "fins" on each of the four sides that can be tilted on hinge points attached to the rim of the can, and cover their surface with the shiny side of aluminum foil. I would make each side around 12" x 12" square, but you may need to taper the lower ends near the jar so they clear each other when folded up.

Good luck!

Jeff Yago

P.S., I cut that photo out of some old movie-star magazine - not sure who it really is.


Electric operating costs

Hi Jeff, since electric companies charge a consumer by the kilowatt hour is their any advantage to running an appliance on 220 volts instead of 110 (assuming the appliance is located close to the electric panel) ? Amperage is cut in half but the wattage is the same.

Thanks,

Christopher

Christopher:

Rule #1 - The electric companies will always get you.

Rule #2 - Go back and read rule #1

Residential electric kWh meters have dual coils, each adding to the spin of the meter. One coil is reading the load on L1 & Neutral leg (120 volts AC) and the other leg is reading the load on L2 & Neutral leg (also 120 VAC).

Any load in your home connected to both L1 and L2 leg (220 to 240 VAC) is being read by both coils together.

This means that it makes no difference of your loads are 110, 120, 220, or 240 volts, the meter will read and spin the dial accordingly.

Note that the meter is reading "watts" not amps and volts. This is why it makes no difference what the voltage is. If you take a given watt load and could cut the amps in half, the voltage will double.

Example - 20 amps X 110 volt = 2,200 watts. or 10 amps X 220 volts = 2,200 watts

Bottom line, connect the appliance to the correct voltage it was designed for.

Jeff Yago


Gravity hydronic heat

Jeff:

I have a home in upstate NY that and I am concerned that its water system may freeze during power outages. I am thinking about a gravity hydronic system using the existing gas water heater and a couple of HW heat baseboard units all connected in a gravity system. Do you think that this is a viable solution? If so, could you point me to some resources that I could use?

Thanks,

Tom Hodge

Tom:

Although it is possible to design a heating system that does not require any pumps or electric devices to operate, there are many technical reasons why this will not do what you think it will.

First, older gravity flow hydronic heating systems worked because their piping was large and routed to promote proper flow. Second, they used a very hot 180 degree water temperature to create the large temperature difference required to create the flow. A typical glass-lined residential water heater is usually heated to only 125 to 130 degrees which will not have much temperature difference to produce the flow, and most hot water tanks are not designed to operate at 180 degrees without damage to the glass lining.

Another issue is normal flow direction. Since you would be connecting the supply pipe from the discharge side of hot water tank up to the heating appliance and the return pipe back to the inlet side of the hot water tank, this is a dead short across the tank. This means when you open a faucet somewhere in the house, the water can flow "backwards" from the cold line into the hot line by passing through the appliance.

Why not install an externally vented gas wall heater that uses a non-electric igniter? You could locate in an central area.

Good luck,

Jeff Yago


Solar powered lights

Jeff,

My name is Peter Amara and I am from Africa. I currently live in California with my immediate family but still have extended family members in Africa.

Most of the communities we have there are a long way from towns and cities and they have little or no access to electricity. Even where it does exist it is unreliable and costly. A solar powered light provides a cheap 'green', and a sustainable alternative.

I was doing a research on the internet and read various articles that you have written in renewable energy and your experience in it for over 25 years now. I would like to not only know more, but to see how I can make some of these products at a semi-mass scale to help my community back home.

Is there a place that I can get hands-on training in building some of these products such as a solar desk lamp?

I appreciate your guidance and eagerly await your reply. Thanks again.

Peter.

Peter:

There are many companies already making and distributing solar products for these parts of the lesser developed world. Sounds like you are trying to re-invent the wheel. These products are already mass produced and their selling price for quantity orders would most likely be better than your costs to duplicate them on a small scale. Contact them for quantity discounts and you can serve as the route to getting them to the people you want to help.

Here are a few links:

http://www.sunoven.com/saving%20lives.asp

http://www.alibaba.com/catalog/11030753/Solar_LED_60W_400W_Street_Light_With_Worldwide_Patent.html

http://www.solar4power.com/solar-power-devices.html

Hope this gets you pointed in the right direction,

Jeff Yago



Read More Ask Jeff Yago

Read Articles By Jeff Yago

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Sorry. Jeff no longer answers questions online

Comments regarding this column may be addressed to editor@backwoodshome.com. Comments may appear online in "Feedback" or in the "Letters" section of Backwoods Home Magazine. Although every email is read, busy schedules generally do not permit a personal response to each one.









 
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