Solar system configuration for a Petrol Station - Suggestions

[thotauk]

Dear All,

We have a Petrol station for which we are planning to install a Solar System on our own. We have some experience of installing Solar PV system at our home. Can some one suggest on how to configure based on the following details. In Rural areas of AP, India no power available during the day. The irradiation is about 5.15 in this area.

Number of motors - 3 (pump1 - 0.75hp, pump2 - 0.75hp, pump3 - 1.25hp)
Pump3 is connected to 2delivery guns. Total stock delivery is about 5000ltrs per day.

We need to operate continuously during the day time and 2hrs total backup will be sufficient at nights(guns operate few times only) I have measured 0.75hp pump initial load which was 4.5amps.

I hope the above information is sufficient for some one to suggest me a system.

Questions:
1. How many panels required in KW's?
2. What are the rating's of hybrid inverter required with MPPT?
3. Battery details?
4. Cables rating?

I would appreciate if you some one help me in this regard.


Best regards,
S

[Mike90250]

I'll just address the power consumption estimate.

3 pumps totaling 2.75 HP Assuming they are REALLY efficient pumps, and consume 1 KW per HP, that's nearly 3KW of power consumed. If they are any less than the latest and greatest efficiencies, they can easily consume twice that much, so that would be 6KW.

Do you know the voltage, amperage, watts, and Power Factor of them ? Are they 1 phase or 3 phase. That all greatly influences the consumed power. We'd have to nail that down better before going any further.

Mike
(my water pump is 0.5 hp, and consumes 1,000w running, and takes 6,000w for 2 sec to start)

[thotauk]

Details

Thanks Mike.

Some petrol pumps here run with 1KW panels for each 1HP rating. The initial power is supported through Batteries. The voltage of the pumps are 240V, each 0.75HP consuming about 4.5amps at start up. the PF is 0.8, and they are in 3-phase.

Hope that helps.

Thanks,
ST

I'll just address the power consumption estimate.

3 pumps totaling 2.75 HP Assuming they are REALLY efficient pumps, and consume 1 KW per HP, that's nearly 3KW of power consumed. If they are any less than the latest and greatest efficiencies, they can easily consume twice that much, so that would be 6KW.

Do you know the voltage, amperage, watts, and Power Factor of them ? Are they 1 phase or 3 phase. That all greatly influences the consumed power. We'd have to nail that down better before going any further.

Mike
(my water pump is 0.5 hp, and consumes 1,000w running, and takes 6,000w for 2 sec to start)

[Mike90250]

So the issues I see are:

1) Running the pumps continuously

We need to operate continuously during the day time and 2hrs total backup will be sufficient at nights(guns operate few times only) I have measured 0.75hp pump initial load which was 4.5amps.

2) being able to recharge the batteries, for 2 hours of nighttime use. This requires the harvest of 3 hours of pump runtime, to account for the recharge losses.

3) having enough solar capacity to run on a cloudy day. Perfect days, you have 4 useable solar hours, 10am -2pm, some areas get more, some less.
What happens when you have 3 cloudy days in a row? This last December, I had 2 weeks of cloudy weather, and had to run my generator daily, my solar could not keep up.

Your station hours are likely 6am - 8pm, many more hours than the 4 core sun hours. I don't think you
realize how large of a system you will need, to have enough batteries to run with, and enough PV to recharge all the batteries. You will have to have a backup generator that will need to run in cloudy weather, no way around it, or else you have to shut the pumps off. Maybe cloudy prices will have to rise, to cover your added costs, since you are the only one dispensing fuel.

I'm also not certain you are able to measure the starting surge of the motor, peak-reading clamp on meters are pretty expensive, and 4.5a @ 240v = 1080 watts per leg, x3 phases = 3240watts running power, which is about right for running, but can easily be 3 times that for starting.
the .8 PF is not too bad, that brings the power consumed up to 3900watts.
3 phase power is more efficient than single phase, but I know nothing about the availability of 3 phase inverters for your country.

So the battery needed to run for 2 hours at night [ again, I'm not able to factor in the power needs for all the other hours from 6am -10am, and 2pm -6pm ]
2 hours, @ 10% duty cycle, is about 12 minutes of run time, with a couple starting surges. that would be roughly 1KWh consumed from batteries. (based on 3900w running load - is that right for all 3 pumps ??) If you use the pumps more that 10%, the consumed power goes up naturally.
A "average" 6v 200ah golf cart battery, holds 1200wh of power, 8 batteries in series gives you about 10KWh of storage, which would be fine. (until we figure all the extra hours the batteries will be used to make up for missing sunlight)

I'm going to sleep now, the numbers are all floating around in my head....

[Ashy]

we have a fuel pump 5 nozzles are there.we would like to run 4 nozzles continuously.each of 0.75 HP.suggest me the system Inverter,battries and panels.

[Mike90250]

It's going to cost a lot of $$$$ if you want to run at night. Only $$ if just in the daytime.

[jflorey2]

We have a Petrol station for which we are planning to install a Solar System on our own. We have some experience of installing Solar PV system at our home. Can some one suggest on how to configure based on the following details.

My primary suggestion is going to be to use an intermediate tank that's above ground. Pump to that when solar (or grid power) is available, then distribute to the dispensers from there. This will either eliminate or greatly reduce the amount of power the pumps need. You can then get a much more reasonably sized solar battery backed system to manage the remaining pumping. (The above-ground tank takes the place of most of your "battery" storage.)

[DanKegel]

Might be tough to keep it from leaking under positive pressure like that. And little leaks can really add up.