What Is The Largest Motor That Might Be Powered Using Solar Power?

Not very practical no, especially when you have to take into account the enormous battery bank required to keep the motor going if the panels aren't generating enough to keep the motor going. As an example, the average solar panel panel size is about 125W at 12V DC. You then need to convert it to 480V 3ph ac (which will substantially reduce the current available at 480V). The number of panels required to power the motor is enormous.

So, no.

Say Jack, thanks for the speedy reply, what size motor might be practical if any?

Some interesting work is underway at the moment on flow storage batteries to address the fluctuating power problem. Essentially, the limitation of a sealed liquid storage cell is that the chemicals in it , once charged, are (obviously) sealed in. In a flow storage battery the charged chemicals are pumped into external storage tanks and replaced with fresh uncharged stock giving you effectively a single battery with an unlimited reserve storage capacity. Brilliantly simple. More info here:

http://environment.newscientist.com/channel/earth/mg19325861.400-a-bank-for-wind-power.html

This link requires a subscription in order to read the entire article. Can you provide an alternate link?

-e

Cormac,

Perhaps you could post the contents of the article here or provide an alternate link.

I have often thought that a similar type of battery (using 2 separate fluids) if it were possible and practical to develop one, could find use in vehicles. the fluids would be exchanged for fresh ones at a "filling station", which would "recharge" them off the grid, and store them to resell to later customers. That would allow for a battery operated electric car that could be "gassed up" in a matter of minutes, and continue its journey.

In conventional storage batteries, the liquid portion of the chemicals are only half the equation: the other half being the "plates", which are anything but a liquid, and changing only the liquid would get you an extra amount of electricity but not that much, and only once since it would completely deplete the plates beyond their ability to be reconstituted. That would be solved if both halves of the chemical reaction took place in "separate" liquids, but I have never seen that to date.

That is what sparks my interest in this subject.

Regards, Greg

Rather than using PV pannels, I saw an article recently where they claimed by focusing the sun (with a trough like reflector) on a pipe they were able to flash water into steam and power a (I assume) steam turbine to run a generator to generate electricity. Maybe that would be a possibility worth looking into. This could also be done in an area that is considered as waste land of which Texas has a fair amount.

What about an external combustion stirling motor?

Solar-Power a company in the US has done that

Why we need to have one -more-energy - converter (solar > heat > steam > turbine > GENERATOR > motor > pump)? when a turbine could drive a pump directly? No problem with speed/torque control too.

To answer main question: What is the max power of the motor driven by PV panel? you must:

• Select type of panel (watt/square meter)
• Available space (square meters)
• Storage batteries

Use DC motor to avoid loss of power on DC - AC converter.

The Calculation has straigh steps to calculate the outpot (available max power).

Second problem is the balance of Energy delivered from Sun = Energy Required to Pump the Necessary Amount of Water. It requires a buffered senergy storage (batteries, what size?). What about Hydrogen solution?

First up... GlobalSpec needs to correct their server errors. I have logged in 5 times and it still is asking me to log in! So my reply may not show up properly.

*

Canada is doing some great things in solar power. Residential/commercial/industrial already. I would suggest you visit this link for starters.

http://www.power-spar.com/Power-Spar/index.php

These systems are "upgradeable" as more powerful PV's become available. They are, to coin an old saying, "plug 'n' play" to get more power.

Anyway check them out.

Later folks

clean out your history, it is your computer who refuses the cookie (or something similar)

I've had the same issues, cleaning my Hard disc solved it.

Is the motor already installed?

As large as you want, really. If you can afford to build 10,000 acres (43,560 sq ft/acre) of solar collectors (PV, thermal, or what-have-you) you can power a gimongous motor. Assume 1 kW solar incidence per square yard, roughly, throw in a lousy conversion efficiency - say 15% - and still you've got 7.3 gigawatts at your beckon call. At noon.

If your motor has to run both day and night (although maybe not all the time; that's more a question for you), you've got some non-trivial energy-storage problems to solve. But it still doesn't limit your motor size; your budget does. So supersize your collector, build a dam, pump it full of water using the excess juice from all that plentiful El Paso sunshine, and go hydro at night. Not efficient, but it solves your storage problem on a large scale. After all, you didn't ask for it to be efficient, just possible.

100 hp × 746 W/hp = 74.6 kW?

Peanuts.

-e

Very close, you have El PASO SOLAR POND. Go to www.solarpond.utep.edu/ from Texas University You can talk about yours needs, by local telephone call. In Brazil, we are thinking to change water plus MgCl2 from usual solar pond to mineral oil. Sure, a different thermal project will be needed to storage solar heat in order to produce electric power.
acquaway@acquaway.ind.br Fernando Vasconcelos

Any idea how much this installation costs? At 100 kW output (after conversion losses), it's certainly capable of powering the original poster's motor - day and night.

Btw, how and with what are these ponds insulated?

-e

There are 800 w/ m² ( watt / square meter ) in El Paso region at least. So, after conversion losses we realize 80 w/m². We need 1,250 m² to get 100 KW emission free energy, day and night, without tax costs. I don´t know the land price in El Paso region. That is the main cost. To build a 35 x 35 x 1,5 m solar pond it´s not expensive. At 1,5m deep and not up 95°C, polyester film for insulated, or any other material will be able and cheap. I thing the major problem in a solar pond is "water treatment" needs. So, we thing to exchange water to mineral oil, more expensive of course but it don´t need any kind of maintenance costs. E-mail acquaway@acquaway.ind.br Fernando Vasconcelos

Working on this now I can relate some basics for you, you need a 480v 120A 3phase feed?

youre going to need somewhere between 1600 to 1700, 175-200W rated solar panels, and utility power connected invereter.

this is about 30,000 sqft of panels. sytem cost- about 2mil$.

you will have about 300,000 kWh a year to work with -an aggrigate. once you start talking reserve storage youre really going to up the costs.

durring peak power, nameplate DC, minus inefficiency & DCAC conversion, while the sun is shining.

I guess the answer to your question is that the size of the motor is dependant on the size of your solar colector. You need to isolate one of the determinents.

Two million bucks buys a lot of transmission line.

-e

Over in El Paso, you might be better off using a co-gen type of arrangement. I've always hated seeing flare stacks wasting BTUs the way that they do, and I've run across some apps for using waste gas to fire a boiler/turbine/Cat. (Cat makes a generator that runs on waste gas.)

The solar app looks like a great idea, but runs into reality problems. DC to 3 phase AC is a pain in the sit-upon (thanks, mom), and acreage/HP ratio is less than optimal.

More details as to the application (location, use) would be helpful in developing alternatives.

The answer to your question as stated is "how much land you got?"

The caracaras might not like it too much, though.

If you come up to Houston, we might buy each other some beers.

Unfortunately 'cost is king`.
Lotsa input missing:

Duty cycle?
Area available for collectors?
Local power costs?
Local equipment & maint. costs?
Are you pumping to an elevated storage facility?
(Can you restrict pump use to sunlight hours and thus decrease battery requirements?)

BTW. Might not a D.C. motor not save on equipment cost
for a solar powered system if you can neglect the inverters etc.?
A charger for utility fill-in would be smaller & cheaper than one sized
to run the motor if you can manipulate the duty cycle.

All around the world, the renewable energy options (except wind energy), can't compite or can not resist any economic analysis vs conventional energy generation, i.e. fossil fuels, or nuclear. So, any application of these systems, has to be, either, because conventional energy is too expensive to buil up, say for instance, a country house up in the mountain, or because there is full conviction, of the enviromental cause, IPCC, Kyoto protocol, and similar reasons.

As for the size of the load to feed, if you browse internet, for the biggest solar project, you'll find out, that in Portugal is under construction or maybe, already finished, this solar power instalation with 11 MW, that means, size is not a problem, evidently, cost is number one, and storage capacity is just a technical matter too, since one could have a huge battery bank for that, unpractical, yes, expensive, of course, but that was not the initial comment, wright?

A warm an respectful greeting from Mexico, to all of you with cold weather up there.

Genaro

sis

I would say to start the other way around. Pick the size motor you need and size the solar pv system to the motor. If you can hook to the grid and your power company will net-meter, that will pay for the electricity used to run the motor. No are batteries needed.

You may have to set up a contract with your power company. This only works if your power company will net-meter or something close to net-metering. Also wind power can be use in conjunction with solar if there is the wind resource. The best way to find out how this works is find a local solar pv or wind installer and get an estimate.

As a proof of concept, definitely yes.

As an economical project, it will be depending on what the alternatives are. But whatever they are, I am quite sure that the answer is no. And that will be the answer until we solve 2 basic problems.The first being the square area per power output of the solar collector. The second is storing energy for no sunlight time. (in case you need 100% duty cycle.) Calculating the KW/h price will be prohibitive for all normal and normal-plus applications.

Wangito

Corrections:

kW/h is the incorrect notation. Schould be kWh

(means: 1000 Watts x 3600 seconds : the practical unit)

By the way what is the average its price in Chile, in USA is about 10 cents per kWh

Uppps, thanks.

Approx .08 US$. (that is 40 pesos.)

Wangito

Thank you Dear Wangito

Your English is perfect.

Do you have Skype (Voice & Text -Comp -Computer) on your computer?

I be glad to talk to you, exchange some tech info etc.

My Skype name is: southern123

rodri,

you could run a DC motor solar on a smaller budget, without batteries the feed will depend on the weather. you could rig a switch to isolate the motor from big swings at the panels. ground to the panel side of the switch and incorporate some controls to suit your needs. DC motors are readily available in smaller sizes say 10-20 hp.

Hmm! Does that answer your question? You didn't say but, did you want your motor to be fully independent of the El Paso power grid? Does it have to be all or nothing...so you need to know a motor size that will work on PV only? All the time the sun shines? Or all the time, period?

Try it. As a former municipal utility maintenance electrician, I found the various vendors to be very cooperative in our work.

As a first application or a test application, I suggest a smaller size, such as 25 Hp. See if you can get a variable-frequency drive (VFD) with no AC input head end, and supply its DC bus directly from your PV array. This would require connecting the array for about 600 volts DC output (the drive supplier could specify what is needed). VFD's have a number of parameters programmed into them for safety as well as control. Your vendor or the manufacturer should be willing to work with you on any possible programming changes or setting changes to make this application work well. If your application is pumping, then much of the time you can operate the motor at a reduced speed and a reduced load.

Talk to Baldor (Fort Smith AR), or Toshiba (Houston TX). Perhaps someone in the American Waterworks Association (AWWA) has some experience or suggestions. --John M.

Everyone is working at accumulating the power, but I note that solar panels produce DC. Thus we have a huge amount of batteries to accumulate the power... say Lead acid... underneath the solar panels. Now let me get a little bit ridiculous.Lets use the hydrogen emmited by these acres of batteries to power H₂ cars!! It is up to someone else to figure how to accumulate the stuff.

So we have an infinite supply of DC electricity... how do we convert that from DC to three phase AC at 60 Hz (or 50Hz). Generating 3 signals, 120 degrees out of phase (at 60 Hz) is simple. a microcontroller can do that. Our micro turns on (or off)) an array of transistors (or relays) to generate the three phases of power. But what we are generating is square wave power... not the three phase sinusoids which are expected by the motor. I don't know if a Bridgeport mill (for example) would handle pulsed DC.

So how do we handle that? Filtering it at 60 or 50 Hz would require some awfully large inductors considering that we are talking of 57.6 KW of power (120 amps) at 60 Hz. Oh and at the same time, we could use the power in heat lost in the harmonics to heat the building containing the filter... somehow...

In any case, I am not answering your original question... how large a motor can I run by solar power... So many variables I cannot, nor can any of us guess...

BUT a good engineer/ scientist/ whatever takes all the information which he can acquire, telling him WHY He cannot do what he wants to do, and finds another way in which to do it.

The only day in which you learn nothing, is the only wasted day.

Sincerely

Bill

You and I are on the same wavelength here, which happens to be DC! The standard method done by Variable Frequency drive people is with Pulse Width Modulation, where they synthesize the sine wave with pulses of DC whose width and spacing changes continuously and repeatedly to create the wave envelope of a sine wave. Pass this through a modest-sized filter and you have a reasonable approximation of a sine wave. Done on three lines simultaneously . . . 3-phase power.

I've worked with them for years. They allow matching the voltage and frequency of the output to the desired speed of a motor, giving a very high power factor and much greater energy efficiency than most other methods available for applications which benefit from a variable speed output, such as pumping, air movement, moving people, vehicles, conveyors, etc. Applications on older motors and over distances greater than about 100 feet (30 meters) requires addition of an output (load) reactor, basically a low-pass filter inductor, to smooth out the higher-frequency harmonics which exist from the pulses creating the sine wave.

I don't know how it is done in a humongous and very high voltage application, such as the Pacific Coast Intertie, which uses DC transmission lines to carry power from Grand Coulee Dam to Los Angeles. But they have been doing it for decades, and more than a couple Bridgeports seem to work on it. I understand that DC was chosen, in part, because some engineer realized that the transmission line length was uncomfortably close to the dipole length of a 60-Hz radio antenna. Imagine--all that power being put in and so little coming out. . .

Peace and consideration for the future--John M.

It occurs to me that we have 'missed the forest for the trees` here.

If a 'green solar` initiative to be sold to the Water Utility is the object, then it would be more cost effective to install whatever solar collectors they are willing to spring for, with an inverter system that 'sells power` back to the grid. Such systems are accepted by most Power Utilities.

The grid then becomes your storage bank and power costs are cut with a smaller investment in equipment. In your location, your output is likely to coincide with peak usage for A.C. cooling so it would be especially attractive to the Power utility.