You need to tell us how big of a battery bank you have, or are planning to have. How amphours total do you need ?
Oso
You need to tell us how big of a battery bank you have, or are planning to have. How amphours total do you need ?
Oso
I would like to ask if you wouldn't mind giving us an update on your progress once in a while. I for one, would be interested and there maybe others on the board that would be interested in following a project like yours from beginning to end.
Good luck,
Oso
You stated earlier that you were considering a system without batteries. I highly recommend that approach. It will save you a lot of money. I have a feeling that what changed your mind was talking to the Jacobs people. They probably need a little juice from a battery as excitation current. If they are only talking about a small battery for this purpose, it is no big deal. But if they are recommending a large battery bank to you, to provide this excitation current and �power during power outages�, they are increasing the cost of your system.
If you are firm on the Grid tie only approach, it is one of your known �design criteria�, at this point. The other is that you want 900-1100 kwh per month. Wind power is not a design criteria, it is merely one of the available resources to achieve your criteria.
But, you are way ahead of yourself, trying to select components for a system, when you are not sure of your resource. Component selection should be step 3 or 4 of the process. So, lets back up and start at the beginning.
Step one should be the preliminary site assessment. In your state, they have a listing of qualified people to perform this function. I would look for either an independent consultant, or a full service installer that handles both wind and solar systems. This site assessment is a prerequisite for participation in the cash-back awards or �rebates� offered in your state.
Whether the person doing the preliminary assessment becomes your �expert� for further steps, or whether you chose someone else for the next steps, will be up to you.
Wind and hydro are very site specific resources. Solar has some site specific concerns, but not anywhere near the wind and hydro concerns. So, a good site assessment is necessary to determine which resource or combination of resources will be the most economical for you. So far, you are just assuming that wind is your answer and it will work. (Maybe it will help you to think of this as your alternative energy system, rather than your wind system.)
The preliminary site assessment will provide you with good educated guesses as to what resource or resources will work on your site. And it will provide you with ball park guesses of the costs.
Step 2 If the preliminary assessment does not yield �black and white� results, further studies and/or research may be required. With wind, wind studies may be called for.
Step 3 is preliminary system design(s) and economics.
Step 4 is detailed design and final component selection.
If a person thinks they have a lot of wind, is thinking small (a few hundred watts) and the total investment is small (let us say $2,000 or less), they can afford to jump directly to component selection. Or sometimes, the expert they are talking with makes that jump for them. It can appear to be a two step process instead of 4.
However, you are thinking a medium size, 3 kw class, wind system. It is a larger investment of $15,000-$25,000 installed. It could run more, depending on a few variables, but particularly your site configuration. And lastly, any mistakes can really drive up the cost.
For �ball park economics� I have selected one of the currently available 3kw machines, assumed a $20,000 installed cost and used a 15 cent per kwh price. Use them for an �order of magnitude� comparison.
15 mph 850 kWh per month 13 years
12 mph 525 kWh per month 21 years
10 mph 325 kWh per month 34 years
8 mph 160 kWh per month 69 years
I want you to look at how these minor changes in average wind speed cause a major difference in the kwh produced, and in the length of the payback period. This is why the wind resource should be confirmed, before going further.
If your site falls at either of the two extreme ends, it is easy. If your site has the something near the 15mph winds you are hoping it has, you can go for it. At 8mph end, it isn�t worth doing, and you should be thinking solar, or possibly hydro.
The complexity will really come in to play, if your wind speed falls �somewhere in between� 8 and 15 mph. It may be a hybrid system of wind and solar, or it may be up sizing the machine class, to achieve better numbers.
Sometimes an expert with his local knowledge, can make an on the spot recommendation, after looking around the site during the site assessment. Other times he may suggest wind studies to firm up the numbers on the wind speed. This will allow him to better specify size and/or mix of the system for you.
So, unless you can afford a $20,000 mistake, you need to follow this process, and confirm the exact wind resource. Are you willing to risk 20 grand or more on an un-validated wind speed map ? (I won�t risk it, even with a validated map)
After an �expert� gives you the size mix and economics of the system (or 2-3 alternative systems) you can make your selection of the final system design, based upon how well it meets your design criteria and the economics.
It would be at this point that discussion of exact components really comes into play. But your selected �final design system� will have ruled out many of the variables that are currently confusing you. Even for experts, that final design concept pretty much drives most of the decisions on exact sizing, voltages, etc., so you don�t even have to get participate in those if you do not want to.
Here is the �Small Wind Electric Systems, a Wisconsin Consumer guide� http://www.eere.energy.gov/windandhydro/windpoweringamerica/pdfs/small_wind/small_wind_wi.pdf
It is really a DOE guide with cover, wind map, and Wisconsin Contacts added to it. As a package it is excellent, one of the best I have seen. I do not know if you have seen it. Please note that the wind map it contains is a 60 meter (196 feet) wind map. It also discusses some of the other people you should be talking with, including zoning, the utility, etc.
Oso
I hope you haven�t bought that Jacobs. Although it was considered the Cadillac of its time, that was 50-60 years ago. It was made for stand-alone operation, not grid tie. And the �40 Volts� sounds like peak output voltage on a 36 volt system. 36VDC is not a system voltage in common use today. A good electrical person can make a workable system with a 36V mill, but it is not something a beginner should attempt.
To stop your head from swimming, just stop thinking about your windmill size, inverter, batteries, etc. Get your site assessment done. When it is done, it will guide you to the right decisions.
Oso
After reading the various links you provided and particularly the additional info at
http://www.spaceislandgroup.com/solarsat.html
I place this idea somewhere between very �forward looking statements� and outright science fiction.
Think about the statement beaming the power to earth on a �weak microwave beam�.
You know that �watts is watts�. So, it is either a very strong microwave beam, or a powerful electric charge riding down the pilot wire of the weaker microwave beam, essentially a continuous lightning bolt. There would be tremendous concerns about this that need to be addressed. I want to see their Draft EIR on this one. I think when it hits the streets, it will be shot down in flames.
And despite their �the technology exists� statements, no one has ever transmitted hundreds of megawatts of power over a thousand miles, much less 22 thousand, by a method similar to this.
They are also going to have extreme difficulties in keeping the solar panel aligned to the sun. Unlike communications satellites which stay oriented to the earth throughout the orbit and focus their smaller and lighter panels towards the sun, these panels are going to have to rotate once every 24 hours so that they stay oriented towards the sun. Without a giant heavy mass in the center, that is going to be extremely hard to do.
I also question their statement that the power will be available 24/7. Although this is true near the winter and summer solstices, I do not believe it to be possible near the spring and fall equinoxes. The unit would have to pass through the earths shadow, or �night time�.
The biggest obstacle that they face is their economics. Every ounce that you lift into space costs you big money. While some of their ideas (e.g. building space stations from expended external fuel tanks) may have some perhaps mutually beneficial ideas, eventually you will run up against the barrier of subsidizing a commercial enterprise with tax dollars. When you combine the costs of this giant solar panel with the costs of lifting it into space, I do not see them doing it cheaper than a bunch of panels (or any other technology we can name) here on earth. The �gravity well� is a huge obstacle.
Bottom line, in my opinion, the roll out date on this is not going to be 2012. It would more likely be closer to 2112, and most likely, never.
Read the section on solar system design. Follow the links they provide, particularly the one on solar insolation data.
Oso
In a hydro system, your batteries should not be dropping that low, because your generator output is based on water flow, and that should be constant. (Solar varies with the sun) The generator should be voltage regulated, so there should be no excess voltage to convert.
If you put a MPPT controler in a hydro system, usually there would be zero net gain, and in many cases the generator and the MPPT controller would end up fighting each other, so there is a good chance that you would reduce the generator's output.
So, install per Mfg. instructions and forget the MPPT.
Oso
I like the energy conservation measures and would encourage you to complete the ones that will impact your electric usage (or at least have strong firm estimates of their impacts), before making final sizing decisions on your alternative energy system. My experience is that conservation is almost always cheaper than generation. Also, take a look at your well pump. If it is say 10 years old or more, a new model might be more efficient. A well is also a prime candidate for a small stand-alone wind or solar application. Even if you just off load 80 percent of your pumping needs onto an alternative system, it can dramatically reduce electric bill. It can also give you experience with an alternative energy system on your site, and that data will help with sizing a big system. Also, look at insulating the hot water heater and all the hot water lines, if they are not already done. It�s a good idea no matter what you are using, but if you have electric hot water, it will also help reduce the total electric bill/generation need.
I also like your grid tie only approach, as it eliminates the need for batteries. Other sites may need them, but if you can get along without them, it reduces the cost and hassles.
�At this time, I'm thinking wind only and not solar due to economics and location.�
For most locations, solar is generally cheaper than wind. So, you either have an exceptional wind location, a very bad solar location, or some of the assumptions made in your economics may be in-correct. I am not saying that they are wrong, just suggesting that you double-check all of your assumptions.
�The average wind speed at according to the Wisconsin Department of Administration Energy Division our location has an average wind speed of 15 - 15.5 mph.�
The 15-16mph range first shows up on the 100 meter map. That is 100 meters (328 feet) above ground level. Hills and ridges can put you up near that height, so that you can SOMETIMES get into those wind speeds with a much shorter tower. However, many times the wind at lower levels hits the hill or ridge and starts pushing the various levels upwards. So, even on top of the ridge, you still might need a real tall tower, to reach those wind speeds.
If you have anything close to the 15mph speed near ground level, the trees on your property (and particularly those near the best potential sites) should show signs of �flagging�. The up wind branches will be shorter than the downwind branches and may be turning slightly upwards. The downwind branches will be longer, and most of the "side branch" branches will be laying closer to the main branch, as compared to the upwind side. If you can not see some evidence of flagging, I would really question the wind speed.
Another sign you can look for, is the existence of other wind turbines (not the old fashioned wind mill pumps) in your general vicinity. If there are not any within 5-10 miles of you, it could be an indication that the area is not really suitable. If you do see them, I would try to make contact with one or more of the owners and ask them about the machines. Have they met their expectations, were there any surprises, etc. While their experience may not be specific to your site, it at least gives you a local baseline. You may also learn who are �the good dealers� and the �not so good dealers� in your local area.
�Currently our average household energy usage is about a 900 to 1100 Kwts per month.�
From the 900-1100 kWh (kilowatt hours) per month and the interest in the 3kW machines, I am assuming that you are trying to reduce your bill to near zero. If your property happens to have 3 good windmill sites, I would give some consideration to using three 1 kw machines. First they are smaller and lighter than the 3kw class, which puts them into a job that can be done by a handy (perhaps very handy)homeowner. (The 3kW class often is a job for professionals, and often requires cranes or specialized equipment.) It is a lot easer to raise and lower the 1kW class. I particularly like the tilt up tower designs that can be used with them. The machines can be lowered to the ground for maintenance, vs trying to work on them in the air. I have seen more people hurt by slips, falls, and dropped objects around towers, than by other incidents. So, I would avoid having to climb the tower at all cost. Remember that you need to pull maintenance at least once a year, and unfortunately, sometimes more often.
Multiple small machines open up other options. You could install one and run it for a year to get some real performance numbers on your property, and then decide whether or not to install the additional capacity. With the 3 kW, you do it all at once, and then if it doesn�t meet expectations, you stuck with the large investment and lower than expected returns. You have no chance to limit any losses, or change your mind.
With the 1 kw, you would have the chance to review it. If (for example) you expected 300kwh and only average 225kwh, you can make the decision to stop there. Or, you would know that with the additional two would make about 675kwh, and you can re-evaluate the additional cost based upon that knowledge. Or if you had bought a shorter tower on the first one, the real data might convince you invest a little more money and go with taller towers for #2 and #3. (actually, I believe in buying the tallest production tower you can get for a specific wind mill. It will generally be the most cost effective in the long run)
With three machines, you always have at least two running, even if you take one down for maintenance or repairs. If you are stuck waiting for a part, you are still reducing the bill by 2/3s. With one big machine its running or it is not.
Depending on where you buy the machines and the exact installation costs, you can often install three of the 1kw for the same dollars as a single 3kw machine.
Also, the available stock towers for 1 kw class machines tend to be taller than those for the heavier 3 kw class. Three 1 kw machines at 100 feet will normally out perform one 3 kw machine at 70 feet, even when located on the same ridgeline.
Wisconsin�s �focus on energy program� will pay 75 percent of the cost of a site assessment for approved home owners. A site assessment runs about 300-400 dollars in most areas. They generally look at all sources of alternative energy for the site, even though the request is for �wind�. It is money well spent at the full cost, and an even greater bargain if you only have to pay for � of it). The info and application form are at
http://www.focusonenergy.com/portal.jsp?pageId=11
The other thing I would look for (and the site assessment should too) is for a mini hydro possibility. A small mini hydro say 400 watts (that is watts (W), not kilowatts (kW).) can produce about 288 kilowatt hours a month because it is running 24/7. If we compared it to a Bergy XL-1 (a 1 kilowatt machine), Bergy estimates about 275 kwh/month when installed on a 30 foot tower in a 15 mph wind speed. The lesson of this example is to look at the monthly (or yearly) production estimates when comparing the installed cost (cost per kilowatt hours per month/year installed) of a system, not the cost per kilowatt of generation installed. (Even in comparing wind turbines against each other use the kwh/month figures, some wind tubine supplies use an unrealistic kilowatt rating)
I hope you find the above info useful, even though it may not directly answer the question(s) you had in mind when you asked. The Alt-E University (tab near top of page) has some excellent info on wind, solar and hydro. I would suggest that you might want to spend some time going thru it, if you haven�t already done so. For further wind info, try Paul Gipe�s site.
http://www.wind-works.org/
And I recommend his books, particularly Wind Energy Basics, highly. It might be available at your library, but is well worth buying, even at full retail.
Feel free to ask additional questions, or for clarification on anything I said.
Oso
Is this a grid only system, grid with battery backup, or off grid ? Are you thinkiing wind only, or wind and solar ? How large of an electric load are you trying to support ?
What is the average wind speed at your site ? is that a measured speed or an estimate ?
Do you have any part of an alternative energy system installed? If so, what ? Or a you just starting to think about it ?
The more you can tell us, the better replies will be.
For best results, your wind turbine should be mounted at least 30 feet plus the blade diameter higher than the highest object within 500 feet.
That should prevent the "20 feet from a residence" that you mentioned.
I like to see the tower located so that it is further away from the residence than it is tall. In other words, even if it falls over, it should not hit the residence. That will make your insurance carrier happier, also.
Self supporting towers are heavier than guyed towers, and therefore more difficult to raise. They also need a heavier foundation.
I strongly recommend a guyed tilt-up lattice tower for the whisper, so that you can lower the turbine and the tower to the ground for maintenence. That way, you will not ever have to climb the tower.
Power poles (or phone poles) should be guyed for most wind turbine applications. If you take a look at the power poles, every time the line makes a turn, the pole is probably guyed on the backside of the turn. Unless you have a concrete foundation engineered for the pole, you will need to guy it. An unguyed pole (set in earth) will start leaning away from your prevailing wind in most cases. You will also either need to learn to climb it, or get a boom truck, for maintenence.
While a rubber mount will reduce some of the vibration from the windmill, the question is will it be enough for you. I do not think so. At least, I can tell you it would not be enough for me. Windmills are bad enough when mounted on a wood framed house. Your motor home is either a wood or metal framed house on an all steel foundation. Your trailer hitch is mounted to the steel foundation. I think it will be like getting a cabin next to the engine room on an all steel ship.
Paul Gipe is one of the wind gurus here in Calif. His site is
http://www.wind-works.org/
Under the small turbine link, you will find a couple of articles on the AirX noise levels and energy production.
For further reading, I have found all of Paul�s books to be excellent, but his �Wind Energy Basics� I would specifically recommend as a real good primer on wind power. It is often available at local libraries.
If the air is always significantly warmer than ambient, the fan may be operating properly and staying on due to internal heating.
Check the air inlets for blockages.
Have you (or someone else) added a large load to the unit recently ? (e.g.Winter time, someone has a resistence heater plugged in)
Is there a heat source near the unit that is "preheating" the cooling air?
Oso
I do not like roof mounting wind turbines on wood structures which tend to dampen the noise. With a metal mast mounted in the trailer hitch, connected to the metal frame, it will be worse.
How much power are you are you trying to generate ? The air-x doesn't produce 100W until you get a windspeed of 17-18 mph. I do not know of many campsites that get that much wind on a regular basis. Even if they do, the turbulance generated by other motor homes, trees etc will reduce it's output.
Have you considered a solar panel or two ?
An AGM (absorbed glass mat) battery is a lead acid battery, and therefore is subject to sulfation. As the electrolyte is fully contained in the mat, the electrolyte is not subject to stratification, which is the other reason for equalizing a battery.
Regardless, of wet cell or AGM, it is preferable to minimize sulfation in the first place, rather than equalize the battery to fix sulfation, after it has occurred. The best way for you to do this is to have a smart marine type battery charger that is plugged into �shore power� whenever the boat is not in use. This will bring the batteries to full charge after each trip, keep them at 100 percent between trips, and shut the charging completely off when not needed. Whether you keep your boat on a trailer or in a slip, this is the best thing you can do to prolong battery life, regardless of battery type.
If you start the trip with 100% charged batteries, the fact that you bulk charge only for a few cycles will be essentially negated by bringing the battery back to 100 percent, and keeping it there, immediately after the trip.
Leaving the battery in a partial discharge state between trips (which is common practice of many boat owners), is a large contributor to sulfation, requiring more frequent equalization.
One of the battery guru�s once wrote that an AGM is not necessarily �a plug and play� replacement for a wet cell. He meant that you need to look at the entire battery / charging system(s) when making the changeover. Older marine shore power chargers may not have the correct voltage settings for the bulk and float charge stages and may need replacement. AGM batteries can withstand a much higher bulk charging rate than wet cells. If you replace the engine alternator with a higher output alternator and regulator, you would be able to accomplish your bulk charge on the water in less time. Or you could achieve a fuller capacity charge in the same amount of engine run time.
Although most (if not all) AGM manufacturers tell you not to equalize the AGMs, if you have a problem with sulfation and explain the symptoms to them, they will usually instruct you on how to equalize the battery and what voltage settings to use.
By the way your use of the phrase �it was never a problem to equalize them every 30 days to bring them back up to speed� bothers me. While equalization every 30 days may be prudent on a large alt energy battery bank (especially for people that cannot or will not take hygrometer readings), it is most probably overkill in a boat or RV that has a smaller battery bank and does not experience as many discharge/charge cycles within the 30 day period.
I view equalizing as a controlled frying or overcharge of the battery. While it will fix the problems of sulfation or stratification, it is not something that should be done too frequently. There is a down side to the equalization cycle, and too many of them will shorten the overall life of the battery.
Oso
So, you will not be able to accellerate the charging thru the inverters. To detiremine if it would be wise to attempt another charging scheme, we would have to know how many batteries you have.
You need to start with your current electrical usage, and figure ways of cutting it down. What could you eliminate entirely and what changes can you make to use less at the new home ? (If you do not make changes, your usage at the new home would be the same as your current home)
After you have downsized your electrical needs (even if just on paper), and have a target figure of how many kilowatt hours a day you will want your system to produce, then you can start designing a system to supply that amount.
You have a real �orphan� collection of mis-matched parts. The best recommendation would be to try selling the individual pieces to people that want them, and then start over from the beginning with components that match.
The MS100 lost it�s UL rating in 1999 with the new IEEE anti-islanding changes. This is probably the reason that Trace no longer handles it. It is still available as the OK4U from the Dutch manufacturer. It is grid tie only (no batteries) and only made as a 24Vdc unit.
You did not say which 12/24 converter you are talking about, but the odds are it would keep the MPPT from functioning, as well as costing you some watts as a parasitic load.
The simplest way of hooking it up would be to buy the matching 102w solar panel and wire the 2 panels in series. This would give you the maximum output that the MS100 can handle (100w). If you are in a good sun region, you might average half a kilowatt hour per day. As an example, at 13 cents a kwh, that�s 6.5 cents a day, so any more money that you invest in this system is going to have a long payback.
Select the heaters that will provide the amount of heat you need. This will set the voltage that you need to deliver, and the wattage consumed by each heater.
Then with an estimate of the time they will run each night (or you can measure it accurately if they happen to be 115AC heaters), the battery bank size can then be sized. If you want backup storage for 1 or more "no sun" days, that will increase the battery bank size.
With the final bank size and either a geograpical location or the low solar insolation data for that location, the PV array can then be sized.
Whether or not one of the powerwize systems will work, would be based on that final array and bank size. An educated guess says no, you will probably need a custom sized unit.
I would suggest that you give up the idea of removing the batteries from the system and carrying them to the rooms. Even if you find a 12 volt heater that would do the job, you might need 2 or more batteries per room to power them. And even sealed batteries can give off fumes, particularly when something goes wrong.
Leaving the batteries in the PV system and providing wires to the rooms will save you a lot of work in the long run.
No, but we might determine if they are reasonable. All we can do is a reverse calculation.
At your rate of $1.63/therm, a $300/yr savings would be 184.0491 therms/yr
The statement is �Typical savings 120-180kBtu/m2/yr�
The traditional BTU is 1 times 10 to the �5 therms. So we can translate the statement to 1.2 -1.8 therms/m2/yr.
The 184.0491 therms per year divided by the 1.2 therms/m2/yr is 153.3742 m2.
The 184.0491 therms per year divided by the 1.8 therms/m2/yr is 102.2495 m2.
153.3742 m2 times 10.7639 (conv. Rate m2 to ft2) is 1650.905 ft2.
102.2495 m2 times 10.7639 is 1100.603 ft2.
So at the 1.2 therms savings rate, your heated space would have to be at least 1650 square feet to save $300 per yr.
At the greater savings rate of 1.8 therms , your heated space would have be 1100 square ft or larger to save the $300.
So, based on the numbers you provided, the $300 end seems reasonable.
Since it is diesel powered with auto-start, I am ASSUMING that it has a seperate alternator for charging the battery, rather than a charging circuit off of the main generator. This should reduce your risk.
If the battery is near full charge by the solar, you should not see the large voltage drop that would occur with a low battery while cranking. After it starts, the alternator will only have to replace what was used in cranking. With a battery that is nearly full, it should not be a massive current inrush.
Many of the solar controllers are designed for use with battery systems that have battery charger backup. Read your documentation on the controller. If it says the controller must be diconnected before charging with a battery charger, you have a problem. If there is no warning about "other battery chargers", it is most like self protecting.
1,000,000 gallons equals 133,680 CF equals 1,336.8 HCF. Times $0.1903 equals $254.40 a month. 1HCF equals 748 gallons or 6,242.5 pounds of water.
�you stated that I'm only moving 1.078 gal. of water 3/4 ft. a second. That was very revealing to me and leads me to believe that I don't have enough flow to drive a turbine even if I did have the pressure to overcome the resistance. Correct?�
You have had the flow (gallons) and the pressure, but not the velocity. Your flow is 60 gpm. This flow is set by your irrigation zones, not the pipe. It results in a velocity in the 3 inch pipe, which is .72 feet a second. (the .75 was based on my 64 gpm est.) When you transition that to your 2.5 inch, the flow (gallons) and pressure remains the same, but the velocity jumps to about 1.04 feet a second. You actually have enough flow and pressure to drive a small turbine, and changing the velocity of the water to maximize the efficiency of the turbine is not a problem. Your problem is what do you do??, or what can you do with the water afterwards???
My initial answer of nothing there was based on the impression that the land rose above the meter. You last response indicating that the meter is about the mid elevation changes things. It is now technically feasible, but most likely uneconomic.
To try to simplify the following example, I am skipping pipe friction losses and working only with pressure equals feet of head. (2.3 feet of water per psi or 0.43 psi per foot.) 150 psi times 2.3 equals 345 feet. So your meter pressure would push water uphill 345 feet. However, if your turbine extracts 80 percent of that energy, the remaining pressure will only push the water uphill about 69 feet. No water above that point. Because of your 25psi nozzle requirement, that knocks off 60 feet more. So, we are left with 9 feet of head for irrigation purposes. So, for practical purposes, we cannot water anything above the meter, with the turbine in the loop.
It would be possible tee off of that main 3 inch water pipe with a smaller diameter pipe and install the turbine, and then return the water to the main pipe. With this arrangement you could run the turbine when watering at or below meter level. But, you would have to shut the turbine off when watering above meter level. So how many hours could you run the turbine? The turbine would generate somewhere around 500 watts. If I assume that you can run it half the time, that would be 30 hours times 500 watts equals 15,000 watt hours or 15 kilowatt hours a week. I do not know what you pay for electricity, but just an example of 10 cents per kilowatt-hour, your return would be $1.50 a week. It is this time limitation, and the reuse (or your primary use) of the water, that really is limiting the hydro possibility.
If you had a stream that ran downhill across your property, and we were able to tap it for the same gpm and head, it would run 24/7, or 168 hours, generating 84 kilowatt-hours and returning $8.40 a week. In this case we would simply dump the water back into the stream and we would have no worries about the re-use of it. Identical turbine, pressure and flow, but we are generating 5.6 times the electricity and revenue.
The turbine that I am thinking of costs $1800. If this was near your house and the solar array that you are putting in, you might find it possible to hook it up to the same inverter that will be used by your solar system. However, if the best location is further away, the installed cost with extra equipment and other problems will quickly drive it to a $10,000 system. So, without a detailed look at your property, I cannot give you a definitive answer. But all my experience says, buy an extra 500 watts of solar and your return will be better at a lower installed cost than the mini-hydro. If you really want to pursue the mini-hydro, you can get a hydro expert in your area to take a look at the property, irrigation system, etc.
I assume that you cut back on your irrigation during the off season. This will also reduce the output of the hydro unit, particularly if you have a no irrigation season. But, with the 500 extra watts of solar, you are still generating when you are not irrigating, so your recoup or offset of �the water energy costs� will be greater on an annual basis.
�I once ruptured a 2.5" line down in one of the canyons with a backhoe and the resulting release of energy was frightening... nearly tipping over my equipment. Now I realize it was the quick release of pressure, not the flow that created this "energy". �
Not quite correct. As soon as you ruptured that pipe, you removed the 60gpm flow limit that we have been talking about. The flow jumped significantly. Also, How far below the meter were you ? If we say 230 feet below the meter, (230 feet about 100 psi) you hit a line with a static pressure of about 250 psi. (the pressure would drop as flow picked up) I don�t even have a reference for an open pipe flow near that pressure, but it was somewhere up in the 500-1000gpm range. I bet you saw it on the bill. Pressure (potential energy) pushes the flow(mass) which gives velocity (speed). The flow at velocity is the real energy.
"there is a 36 in. main under the county road that I tap into. Although I can't even imagine such a large pipe, it is possible that there is more pressure at the meter than I have stated."
The 36 inch main will have higher pressure than your meter pressure. Somewhere after the tap off, there will be a regulator, probably right before the meter. (often in the same concrete box) The pressure at your �house� gauge will be the same as at the meter, other than the few feet difference in elevation. (assumes no regulator between the two, and it doesn�t sound like there is.) You probably have a regulator to drop the pressure for the house somewhere after that gauge.
The 36�inch pipe is medium size. I�ve worked with 72-96 inch water pipes, over the years. And if you get away from water systems and into hydro plants, there are �water pipes� much larger.
The first thing is that I do not find the .1903 per hundred cubic feet to be excessive, as it takes a lot of work/energy to pump water. (Look back at the horse power and electric consumption rate examples in my earlier response.)
On your approximate 1,000,000 gallons a month, the surcharge is about $25.44 a month.
1,000,000 gallons equals 13,368 CF equals 133.68 HCF. Times $0.1903 equals $25.44 a month. Your total irrigation bill may be high, but the energy surcharge is not bad at all.
(That or I miss-read the 19 cents per hundred cubic feet.) 1HCF equals 7,480 gallons or 62,425 pounds of water. They have to push it from the river (or other source) up to your meter and then several hundred feet up beyond the meter. If you look at moving units of 62,425 pounds uphill, for 19 cents each, what a bargain !
Next, your hills cannot be 600 feet high, based on the info you have provided.
150 psi water pressure will theoretically push water to about 350 feet before reaching no pressure, no flow. You need to knock off 60 feet (or 26 psi) to maintain 25psi nozzle pressure. (I wanted a rough idea of the number and average length of your � pipes to get a good idea of the friction loses per zone.) But not having those, I can guess. The safe estimate would be about 250 feet, which would be knocking off another 40 feet (or17psi) for total friction losses. But, if your system has similar velocity rates in the smaller zone piping as in your main feed trunks, I can see an elevation of about 275 feet, as a higher figure.
So, either your meter pressure �reading� is wrong, or your hills are lower than 600 feet. I suspect the latter, or a combination thereof. You would be running over 300 psi to reach a point of 600 feet, after allowing for nozzle pressure and friction loss. I also know how even people that are real good at estimating distances on the flat or heights of poles or buildings, (like me for example) get thrown off by heights up a slope. Or even worse, estimating down a slope.
But it is somewhat a moot point because you are obviously getting the water to the top of the hill.
On second thought, it isn�t moot to you. If the �600 feet above the meter� got into the water district records and your energy costs are based on the highest elevation being 600 feet above the meter location, you may be overpaying. That might be worth looking into.
If the water districts records show anything more than 275 feet above your meter, ask them to send a man with a pressure gauge out. Measure static pressure at the meter (zero water flow anywhere on ranch). Make the same static measurement at the top of your highest pipe. Subtract the low pressure (High elevation) from the high pressure (meter elevation). Multiply the remainder by 0.4335 psi per foot. You will have your elevation above the meter. If he does both (without the flow anywhere) with his calibrated gauge, the �error� will be within half a foot (plus or minus). The difference calculation based on an un-calibrated gauge (same no flow conditions) should be plus or minus 3 feet, at worst.
They should accept their own readings, if not yours.
I was going to recommend solar to you after looking for conservation measures around that pump that does not exist. I am not upset about that, I just �knew� that your 150psi would not reach 600 feet and therefore, you must have a pump. When pumping to various elevations, there are ways to make sure that you are not over pumping the system. If over pumping exists, that is all waste energy. Solving �over pumping� saves energy and reduces the electric bill.
I do have some general recommendations about solar that I can provide, if you are interested.
You are correct in that your actual system pressures will vary all over the place, not only due to elevation, but to pipe friction losses.
There are 2.307 feet of water per psi or 0.4335 psi per foot. For most purposes, we can generally round them off to 2.3 feet of water per psi or 0.43 psi per foot.
It does not matter if you are pumping the water up hill, or running water down hill for generation, these are the numbers for the change in elevation, only.
Your additional info helps a lot. But I do need clarification on the wording:
�2 to 3" pvc pipes climbing to the highest elevations, then 3/4" pvc branches that drop back down the hillsides at various lengths. From those branches, risers with 25 psi regulators��
Depending how I read that, I see either the � branching off at various elevations as it climbs or I see everything going to the top of the hill before branching, and then running back down. If you can clarify that for me, it will give me a better idea of your potential savings.
Also, what is the typical number of � pvc pipes per 60 gpm zone ? What would be the typical or average length of a single � pvc pipe in a typical zone ? This would help for evaluation of friction losses.
And lastly, how does your pump fit into this picture ? It sounds like it is running all the time, even when you are watering below say 200 feet. Is that true ? Anything you can tell me about it off the top of your head, horsepower, typical pressure when running, etc. will help. Also, does it have any type of speed control on it (rheostat or electronic speed control) ? Or, just an on and off switch?
Just to give you an example of where I am going, consider the following example:
The horsepower requirements for pumping water are (based upon 55% pump efficiency and 60 gpm and no incoming water pressure) 300 feet 8.26 HP, 400 feet 11.0 HP, 500 feet 13.8HP and 600 feet 16.5HP.
Just using those numbers, you can see that pumping water only to the height needed saves work and energy.
If we convert the HP figures to kilowatts at .7457KW/hp, one hour of pumping 60gpm to 600 feet requires 12.12kWH while the same hour of pumping to 400 feet requires 8.22kWh. At a rate of 10 cents a kWH, the hour to 600 feet costs $1.21 and 400 feet is about $0.82.
Conservation of electricity is almost always cheaper than generation.
Oso
With 4.3 weeks a month, that would be about 258 hours a month. That would be about 3875 gallons an hour or about 65 gallons a minute. 65 gallons is about 44 feet of 3 inch pipe. So your velocity is about 44 feet a minute.
Expressed in seconds, 1.078 gallons at 0.74 feet a second. No, there is no generation in that 3 inch line, as you are currently running it.
Based on the pipe size and flow, my guess is you are running a system of spray nozzles (or possibly drip?) with some pretty long pipe runs involved. If that guess is correct, even if the flow and velocity was there, you would not want to insert a turbine because it would probably result in an unacceptable pressure drop and reduced coverage at the furthest nozzles.
If your system is different than my guess, or if you have some flood irrigation, pond filling, large tank filling, etc that is hidden in your numbers, that might change the possibilities.
The other piece of info that would be helpful in any future conversation would be what type of pressure is typically in that 3 inch pipe.
However, there is one big red flag for me. A 1,000kW genny is gigantic. I would tend to believe that you are looking at a 1,000 Watt (or 1 kiloWatt)generator.
In that case, your revenue would be 81.6 cents a day.
The worst thing about his idea is the exposure to 12,000 to 15,000 volts (depending on the exact winding count). It is too dangerous for anyone except a high voltage electrical worker. I cringe at the idea of children getting anywhere near it. (why do you think the electric company puts it up the pole or buries it ?)
If you ever have fire and the electrical is suspected as the cause, your fire insurance company will probably refuse to pay and cancel your policy, just because of the transformer.
His suggestion is plain foolhardy.
Yes, it is possible. But, it does not make sense. If you have to run your pump for 2 hours a day now, the backpressure/reduced flow caused by adding the turbine will make you run the pump longer (say 3-4 hours), to accomplish the filtering of the water. Since the swimming pool pump will consume more power than you can possibly generate, your net cost for electricity will go up, not down
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