Need to create a wind / solar system which outputs 48Vs:

Hello.

I am new to the forum and also the world of renewable energies.

We have a water purification system that requires 48V to run the two pumps. We need to operate the system via Wind/Solar system.

We would like to use the Bornay wind generator (1500W) and 6 solar panels at around 200kW.

So my question is does it make sense to use wind generators and solar panels at 24V and then put two batteries in to series to have 48V for the water pufication system?

Or is it better to use a wind generator and solar panel that already is at 48V?

I found a good wind generator at 48V (Bornay). Does anyone know of some good solar panels (around 200kW) at 48V?

Also if anyone has some good articles or advice on how to set this up, I would greatly appreciate it.

The location is on the north coast of Colombia where there is tons of wind and sun. The water purification will be near the ocean so the wind generator and solar panels have to be durable against the salt.

If you need more details, please ask.

Simon

Comments

  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Need to create a wind / solar system which outputs 48Vs:

    simon,
    i am not familiar with that wind genny, but i'm sure it'll do fine for you. you should have all at 48v unless you want to take the pvs slightly higher and use a controller like the mx60 to downconvert to 48v, but you definitely don't want either the solar or wind power to be less than 48v as that's what you'll need.
    as to the batteries, unless they are 24v aircraft batteries going in series you'll need 4 12v batteries or 8 6v batteries in series to get 48v and if you need more current you'll have to duplicate that and place in parallel until you reach your current needs.
    now that brings us to a question for you as we'd like to know the current consumption of your pumps and how long the run time will be in a typical 24hr period? this determination will help in finding the battery capacity you'll need. also we'd recommend a 3 day backup period the batteries could run at without sun and not exceeding 50% of their capacity to preserve battery life.
    do note that if you are looking for 200 kilowatts (200,000 watts) of pvs this would be extremely expensive and i hope this is not what you'll need in pvs. i'm hoping you may mean 2kw or 200w so please clarify this for us.
  • System2System2 Posts: 6,290 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    Oops.

    Yes, I meant 200w solar panels. Sorry about that. : )

    Which setup is better - 4 12V batteries or 8 6v batteries?

    It is important to note that this system (wind/solar and water purification system) will be for a local community in Colombia. We are trying to make the complete system as simple as possible. So the less parts needed the better. The same goes for the maintenance issue.

    Having said that, which solar panels and batteries do you recommend that have little or no maintenance and can deal with the salty air without any problems?

    As for the current consumption of the pumps and how long the system will run I can not answer that until next Monday. But I will post it here as soon as I have the info.

    So as far as components I need for the energy side of the system I need the following:

    1500W wind generator
    6 200W solar panels
    4 12V batteries (or 8 6v batteries)

    Am I missing something else?

    Thank you for the quick and very informative response.

    Simon
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Need to create a wind / solar system which outputs 48Vs:

    simon,
    no problem. we realy don't know if the items you specified are sufficient or not until we know what your power consumption is. as to maintenance free batteries the absorbed glass matt or agm is very good and many manufacturers make them.
    as to solar panels taking salty air i would imagine most of them qualify in that respect. many are leary of thin film types at this time including the hybrid types offered by sanyo due to warranty issues. usually the thin films have 20yrs or less on performance, but these do generate as i have 2 unisolar 64s and they are more durable in many cases than the crystaline type with glass. the efficiency of many thin films aren't very good, but sanyo does have good efficiency on theirs. i'm not pushing thin films either as the crystaline type is more generally prefered and tend to have better warranties and efficiencies.

    I MODIFIED THIS POST
    it seems that in general looking that many crystaline pvs are also going with 20yr warrantees on them for their output now. what's up with that?
  • BB.BB. Super Moderators, Administrators Posts: 30,219 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    You are missing a charge controller (Outback's MX 60 is considered to be one of the best MPPT). But any good MPPT controller (probably sealed construction) should be fine. I believe you will need two charge controllers, one for the solar panels, and another for the wind turbine (plus you may need a "dump" load for the wind turbine controller).

    You can look for AGM batteries--properly maintained (good charge controller with temperature compensation) will be much less maintenance (no distiled water needed to refill the batteries).

    Also, a good battery monitor would be helpful to ensure the batteries are properly used/charged:

    http://store.solar-electric.com/metersmonitors.html

    Another issue is will the installation be safe from thieves. I would suggest that you check locally for anything to be purchased--it may be cheaper to buy and maintain locally than shipping from the US (or not)...

    Also, you may wish to buy less expensive items first to see how the installation survives (plus you could purchase some spares too with the money saved).

    Lastly, you may be able to separate the needs for pumping of well water by only pumping (to a tank) when sun/wind is available (may want a linear boost converter too for the DC well pump) with a battery-less system. Only use the batteries for purification and domestic water pressure (if needed).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Need to create a wind / solar system which outputs 48Vs:

    you are right bill i left out talking of the controller as we do not know his needs as of yet. heck the wind generator may accomodate all of the needs as we don't know yet. most wind gennys come with their own controller or regulator. if not then you have to get one. odds are they will have need of a controller like the mx60 though and it should have a battery temperature sensor for it. if you can, research the wind genny for such a feature as the temperature plays a role in the proper charging voltages for the batteries and agms are very prone to overcharge damage unlike the standard lead acid types that you can add distilled water to. once an agm outgasses, those gasses that escaped cannot be put back in so battery capacity/life is diminished.
  • System2System2 Posts: 6,290 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    Wow! Lots of good information here.

    Thank you. As soon as I have the information on the water system, I will post it here.

    Have a good evening!

    Simon
  • BB.BB. Super Moderators, Administrators Posts: 30,219 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    About the water purification system... Apparently there is a company out there that is displacing many of the pump/tablet type purification systems for the camping/survival market.

    http://www.sawyeronline.com/products.htm

    There are two basic kinds, one that works for anything down to bacteria--and another that works even on viruses.

    The filter looks just like a car's inline fuel filter. But internally they use hollow fibers for the filtering. The filter can operate up to 40-60 PSI or can be placed in a water bottle and used like a "filter straw" for personal drinking.

    They are not cheap (at least retail)--they run upwards of $120 each--but they are rated for 3,000 gallons of purification (I assume you pre-filter dirty water--and you also backwash--with cholrine bleach if no fresh water available--every so often). The filters fail only by eventually becoming hard to draw water through. And are rated to exceed EPA limits for purification.

    They are so small and simple, I would suggest that that well water could be distributed from a tank around the place (town) and just use these filters for drinking and cooking water.

    Requires very simple infrastructure (a few PSI of pressure--even use a plastic bag hanging from a branch) and very small chance of undetected failure in purification. No expensive and/or difficult machines/chemicals/etc. required.

    Otherwise, I would be interested in hearing about your proposed purification system.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • crewzercrewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: Need to create a wind / solar system which outputs 48Vs:

    And, here's a link to several 200 W PV modules: http://store.solar-electric.com/hiposopa.html

    Note that, because of the specs and likely operating voltages, six of any of these modules would have to be wired in some sort of a series-parallel configuration in order to deliver a voltage high enough to charge a "48 V" battery bank (nominally ~56 V to ~62 V). The MX60 controller would be a good match for these modules.

    HTH,
    Jim / crewzer

  • System2System2 Posts: 6,290 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    Hello again.

    To have a better understanding of what the project is about. Check out the website of our non-profit organization at www.aguayuda.org

    The project description can be found at:

    http://www.aguayuda.org/Eng/Proj/Almendros.cfm

    And the RO filtration system is explained here:

    http://www.aguayuda.org/Eng/Sol/Fil.cfm


    Though we may construct the RO system ourselves, we have found some excellent commercial compact RO water purification systems. One company will provide us the technical details of their system next week. Once I have this information, I can post it here.

    Having visited the community last October, thieves will not be an issue. I agree with buying as many components as possibly locally. Luckily, Bogota (capital of Colombia) has many companies regarding wind and solar panels. However, we will build a prototype in the states first.

    Yes, the charge controller is what I forgot. Thanks for the tip on the Outback's MX 60.

    Though our organization feels confident with the water purification side of the system, renewable energies is a completely new area for us. Hence, the basic questions that I am asking.

    I truly appreciate the excellent support.

    Simon
  • BB.BB. Super Moderators, Administrators Posts: 30,219 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    Simon,

    Looks like an interesting project. I sometimes question the settlement of anyone on small spit of land with little in the way of natural resources (water, land, protection against storms) through the use of non-locally sustainable technologies--but I am here and you and your group are there--so I am sure that there are very good reasons things are the way they are.

    Anyway, back to your issues... First, it would be best to know your power requirements (watt*hours per day/week/month/by season--if it changes) and the power requirements themselves (voltage, frequency, maximum current, average power for how many hours per day).

    Somebody here should have the link to a world map (I could not find it--it has been posted here before) that will help predict how much radiant energy there is in Colombia. The photos have lots of dramatic clouds--hopefully, this does not represent the normal day to day weather of the area.

    And we would need to know the available winds (it is hard to get working wind power from winds that are less than ~10 mph sustained--and pretty much impossible below ~6mph or so).

    Also, are there any special issues... I see that only "renewable power" is allowed in this reserve... When designing the system, knowing the limits of the requirements (such as 3 days without sun/wind of battery reserve). If this system must always be available, having a backup generator available (gas, diesel) would be highly recommended for emergencies.

    Again, breaking up the pumping requirements--those that are required for pumping to raw storage (which can be done only when sun/wind is available) vs the power required for the RO unit.

    Is it worthwhile to collect & store rain/surface water for later filtration (less power required for fresh water than salt for RO).

    Would it be a good idea to also support lighting (CFL) for one or more buildings? Much of the time, if the system is designed to ride through poor weather/power collection, there will be excess power available to support "optional loads".

    Just out of curiosity, how much water (fresh from fresh or from salt) is needed and how much power is required to produce a gallon of water from the various sources?

    Is there also a budget for the parts and maintenance? Solar panels are (obviously) expensive. Wind Turbines don't seem to last very many seasons before needing major overhauls and/or replacement (plus a way to access the turbine at the top of the mast--crane or tilt mast). The typical batteries will only last 3-10 years (depending on price, usage, and maintenance).

    Are you going to be able to place this in a container (keep salt air/humidity to a minimum)--I grew up on the coast of California--anything near the coastal fog needed lots of TLC. It appears that the RO (and power?) will be installed near the visitor's center--so the equipment will be away from storm surges. Panels and towers protected against blowing debris?

    Will you be allowed to install a tower for the wind turbine (need to be well above any local obstructions and up in the air flow to get good winds).

    It sounds like a very interesting engineering project--weighing all of the possibilities vs money and resources available.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    Hello Bill,

    I understand your point about questioning the settlement but it is important to know that we are working directly with the national park who requested a desalination system. And since there is a small community nearby, it makes sense to provide water not only for the national park but also the community. Also by providing water, there is a good chance tourism will increase which will benefit the community via jobs and handcrafts they would like to sell.

    Having said that, the fact that we have to use renewable energies makes this engineering project much more challenging. It would make our lives much easier if we used a small generator that produced the energy we needed. The national park seems to be against this for obvious reasons though generators have come a long way and are much quieter and environmentally friendly than they used to be.

    Collecting and storing rain is an option though it rains very little there. As for lighting, the national park has not requested this at this time.

    There is a budget for the parts and maintenance. It will be covered by the national park and a small fee that the community members need to pay (6000 pesos - $2.50 per year). Of course this budget will need to be revised once we know what we are buying.

    As for the technical questions, I will have this information by next week.

    Thanks for your interest.

    Simon
  • BB.BB. Super Moderators, Administrators Posts: 30,219 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    Just some back of the envelope calculations for Reverse Osmosis. Using the numbers from small units intended for boats:

    http://hrosystems.com/reverseosmosis/brochure.html

    Their Escape 400 model produces about 17 gph (65 liters per hour) or 400 gallons per day (1,515 liters per day). Requires roughly 7 amps at 24 VDC (0.33 hp motor).

    Assuming that 7 amps * 24 vdc * 1 hour = 15 gallons of fresh water (no UV disinfectant, no low pressure feed pump for pre-filters). (Note brain freeze here--started with 17 gph, used 15 gph below--BB)

    (7a*24v*1h)/15 gph = 11.2 watt*hours per gallon (seems to be about right compared to a "15 watt per gallon" you spoke of in one of your links (I assume 15 watt*hours is what you really intended. And another place looking through the web showed about 1 Amp*hour per gallon for an, assumed, 12 vdc system).

    Assuming you have good sun and weather (using San Juan PR as closest US solar data near Columbia):

    http://rredc.nrel.gov/solar/pubs/redbook/PDFs/PR.PDF

    Using a simple fixed array would give about 5.5 kWhrs per day per sq. meter... Or, roughly 5.5 hours per day of sun. You were thinking of 6 x 200 watts of panels, which would give about (at 85% derating PTC/STC of real-life vs lab rating of panels)

    Solar Power per day = 6 x 200 watts * 5.5 hours per day * 0.85 = 5,610 watt*hours per day

    Amount of water produced using solar panels only:

    (5,610 watts / 11.2 watts per gallon) * 0.80 for battery charge eff = 400 gallons per day (average over 1 year).

    Is this, roughly, the amount of water you were expecting? Wind will provide more energy--but pending understanding the wind profile of your site--I would assume that you would only use wind as "make up" power for stormy weather at this point.

    The cost of the water, just based on the cost of electricity of ~$0.25 to $1.00 per kWhr (typical range of costs for Off-Grid power of solar--capital costs/life-- and generators--cost of fuel/excluding capital costs--excluding costs of managing/procuring non-indigenous supplies for use in Colombia):

    5.610 kWattsHrs * $0.25 per kWhr / 400 gallons = $0.0035 per gallon
    5.610 kWattsHrs * $1.00 per kWhr / 400 gallons = $0.0140 per gallon

    Assuming 1 gallon per day per person per year--Just power costs would range $1.28 to $5.11 per year per person.

    Using one of the viral, disposable, filters (assuming sweet water supply), guess at $60 per filter (wholesale) and 3,000 gallons life, and 1 gallon per person per day per year:

    ($60 per filter / 3,000 gallon per filter) * 1 gal per person*day * 365 days per year = $7.30 per year using non-salt water and personal viral filter

    You mentioned that there could be a water supply less than a mile away--although it was not year round (?). It seems that a low(er) tech solution of pump/storage/sand filter + personal viral filter (or even chlorine generated from salt water + electricity to limit the need of a viral filter) may be at least as cost effective, good use of local labor (building/maintaining pump/storage/sand filter/distribution system) and supplying a one personal viral filter per person every 5-10 years. Plus, it could be sized for irrigation of home gardens and animal needs (if this is a need). An RO system would seem to be difficult to justify for agricultural use.

    Granted, all of the above are based on SWAGs (Scientific Wild A$$ Guess)--But I assume that RO units are not cheap to buy and maintain either...

    -Bill

    PS: I see I had a brain freeze above... the unit's rating is 17 gph, not the 15 gph that I used through the calculations. I will leave the above as is--It is still within 10% of the range guesstimated--Solar/Wind/system variability is much more than this (plus you would probably need, at least, another 10-20% power for the feed pump to supply the pre-filters and UV/Disinfectants).
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    Hello.

    Interesting breakdown.

    Unfortunately, there is not a realible water source near the community (besides the sea water). During the dry season, the closest rivers are basicaly dried up. As I mentioned before there is not much rain during the year. The nearby communities are receiving water from a water tank truck. This service has been very unreliable and is not even enough for them let alone for the community in question. It is also important to note that a truck could not even drive to the community during the rainy season because the ocean water flows into the lagoon. You need a boat to cross this small channel.

    I will post our water system info ASAP. I see I have found an excellent forum to help us out.

    Time for lunch. :-D

    Simon

  • BB.BB. Super Moderators, Administrators Posts: 30,219 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    Simon,

    I am sure you know more about the fresh water problems than I -- However, that has never prevented me from adding my two cents worth...

    I still believe that low-tech for water treatment is going to be a better place to start in a small, cash poor, village. What are your comments on using a solar still such as the project here? (article talks about trying various low and high-tech systems in southern Africa--Botswana):

    http://idrinfo.idrc.ca/archive/corpdocs/049547/index_e.html

    It also appears that they could be built small enough to be constructed/operated on a per family basis to generate fresh water (4-7+ Liters per day per sq. meter of collector surface). You still may wish to supply some secondary local treatment (chlorine, viral filter, etc.) but it seems that this would not be the worst first step out there.

    The paper is now over 20 years old, so many of the cost assumptions have changed (price of oil and technology). Their conclusion was that these small stills were not the best end-solution, but were a good start on the way to a better life and further development in the villages.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2System2 Posts: 6,290 admin
    Re: Need to create a wind / solar system which outputs 48Vs:

    Solar still has its merits but the major problem is that it does not provide enough drinkable water compared to a membrane filtration system. We were at the Water forum in Mexico last year. That is the largest water fair in the world. Sure enough, we saw some solar stills. They are excellent for a small amount of people but once you get past the 100 person mark, they are not practical anymore. There were some other organizations using membrane filtration systems to provide water for rural communities. When setup properly with a water committee maintainig and operating the sytem, the results were amazing.

    Having been in the Peace Corps and volunteering in various countries I completely understand the dangers of using solutions that are not locally based. But I am convinced there are certain problems that need a more modern solution. Of course, we are making sure that any replacements parts needed can be bought in Bogota, Colombia. Otherwise, it becomes complicated if you have to ship parts from the United States.

    If you look at our second project, we are dealing with about 1200 families (10,000 people). Luckily, in the second project there is a useable grid for the membrane filtration system. And in the second project the water we have to clean is coming from a river so no need for RO which means the pressure needed for membrane filtration is much lower.

    Great discussion!!

    Simon
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