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Member

Join Date: Jun 2006
Posts: 6

# Calculate System Power

06/10/2010 10:44 AM

Hello friends . I want to organize a solar power system for water pump. Pump for a agricultural field, it is 10KW. This pump motor works 4 hours for a day. 2 hours running then waiting 3-4 hours. after runs 2 hours again. How much KW power of Solar panel and battery do I choose?

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Commentator

Join Date: Apr 2010
Location: Western Australia
Posts: 92
#1

### Re: Calculate System Power

06/10/2010 11:59 AM

If the pump works for 4 hours a day, then that about matches the peak time for a solar collector system. If your pump is 10 kW, then your solar panels are going to have to be close to 10kW too. That is a substantial outlay.

It depends on what time of day you need to do the pumping. If you can do two hours of pumping close to solar midday, then you can reduce your storage, be it battery or tanks.

If not then you are up for substantial storage. Better, I suspect, to use a head tank than batteries, but it depends on your location and whether you have sufficient elevation available to get the required pressure.

Guru

Join Date: Jun 2008
Location: Oman
Posts: 612
#2

### Re: Calculate System Power

06/11/2010 12:34 AM

Guru

Join Date: Jan 2010
Posts: 2446
#9

### Re: Calculate System Power

06/13/2010 2:47 PM
Member

Join Date: Jun 2006
Posts: 6
#3

### Re: Calculate System Power

06/11/2010 3:34 AM

can i select 5KW panel system and 10KW battery system. as you know panels charges to battery till 10KW then i can supply to 10KW pump motor?

Active Contributor

Join Date: Nov 2009
Posts: 14
#4

### Re: Calculate System Power

06/11/2010 5:00 AM

Hello, Just to be sure here: you have a 10 kW pump, need to run if for a total of 4 hours a day. The first aspect you have to see is the energy you will need every day. In this case, multiply 10kW times 4, so that is a total of 40 kWh.

As was mentioned earlier, you have to define the time at wich the system will work (mornings, afternoons, nights), and then define the ampunt of days without sun you might have in a year (this will depend on where you live, also if you have a radiation per month graph, that will help you a lot, because you can actually design based on the worst month). If you have all that, I think we can further help you out!

Member

Join Date: Jun 2006
Posts: 6
#5

### Re: Calculate System Power

06/11/2010 10:48 AM

i will run the pumping motor 2 hours around 10am. 2 hours around 10pm.

Active Contributor

Join Date: Nov 2009
Posts: 14
#6

### Re: Calculate System Power

06/11/2010 10:58 AM

Hello again,

Ok, where are you located exactly? do you have radiation data?

Becasue you will run the system at day, than I would say that you could dimension the batteries for two hours of load, of course, once again, it will depend where you are!

Guru

Join Date: May 2010
Location: Metro.Manila, Philippines.
Posts: 1222
#7

### Re: Calculate System Power

06/11/2010 11:33 AM

You also need to specify the type of prime mover is driving your pump? AC or DC motor? If AC, you need an inverter for AC conversion. If operation is during the day, batteries may not be needed or necessary, another cost savings?

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vsar
Member

Join Date: Jun 2006
Posts: 6
#8

### Re: Calculate System Power

06/12/2010 2:35 AM

Thanks to all of friend. I am from south of Turkey. There is lot of sunshine.

Power-User

Join Date: Jun 2010
Posts: 348
#10

### Re: Calculate System Power

07/11/2010 4:56 AM

Why you must have a 10 KW irrigation system? Why you should have intermitent pumping cycle while considering solar energy? and why you must have to provide for the batteries?

Keep the pump runing whole solar day to fill a slightly elevated reservoir, batteries are not needed, you will use the stored water during any part of the day or night for irrigation.

Small scale irrigation systems of less than 2 KW are economically competitive with conventional pumping systems.

Peak flow of 1.5 to 3.5 l/s (ie, about 25 to 60 cubic meter / day) are required for irrigating 0.5 to 1.5 ha land holdings, lifting water between 2-7 m. The required peak power output (i.e. hydraulic power) range is thus 50 - 300 W.

Use a single-stage centrifugal pump directly coupled to the DC motor. Achieve a good overall performance under varrying levels of solar irradiance by matching optimum efficiency of motor-pump combination to coincide closely with that of solar array.

Select small pv modules (20Wp maximum) with open circuit voltage of about 80 v.

In Turkey I guess isolation of the range 6 kWh / sq. m on a horizontal plane is there, if the climate is humid use a figure of 5 instead.

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