Solar Air Compressor

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pechan
pechan Solar Expert Posts: 92 ✭✭
Hello All,

I have been tasked with finding a replacement source of pneumatic power for a gas well.
Currently natural gas is being used to power pneumatic actuated valves and when the gas is no longer needed to power
the actuator it is vented to atmosphere. This is upsetting the EPA and they are starting to issue citations and large fines for this practice.

I need to come up with a solar powered compressor in order to use air to actuate these valves instead of natural gas.

30-60 psi is required, and I have yet to figure out how many cubic feet of air is needed at this pressure (I know I need to start here)

But I want to see if your minds think this is feasible. Idealy (ok.. in my dreams) I come up with a batteryless solution to avoid the #1 problem with solar.
I know there are batteryless water pumps such as the SunCentric solar water pump sold by our host. The idea being to store enough air for cloudy days/oversize the solar bank etc.
I would like to make it as industrial as possible by using a cast iron compressor pump 1/2 hp? I need something that can be overhauled when needed. I would like to keep the solution
in the low 4 figures as far as price.

What do you guys think? Is this feasible? What about cloudy days or low light how would a motor handle lower wattage?

I'll start with that and see where this goes.

Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,478 admin
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    Re: Solar Air Compressor

    You can do this with several different motor solution...

    There is a brushed motor--I don't like brushes, they can need replacing every 6-12 months (depending on duty cycle, etc.).

    An interesting possibly is a 3 phase motor with a VFD configured to take power from a solar array. We are starting to see large water pumps being done this way (as our friends from Pakistan/India here--and there are more and more "Solar VFDs" from China).

    You can go with Permanent Magnet Motors and a form of VFD/Drive (PM motors could be ~20% more efficient than induction motors).

    SunPumps may make stand-alone motor systems. You would need to contact our host or SunPumps directly.

    If you have enough wind, there are folks that make Wind based air compressors (air lift well pumps)--So that is a possible alternative/supplement to solar.

    Any way, that it were I would start looking.

    An alternative would be to combust the natural gas instead of venting it--But I am sure that may not get you many friends around the oil patch.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • solarix
    solarix Solar Expert Posts: 713 ✭✭
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    Re: Solar Air Compressor

    How about a Bo-John windmill that simply puts a standard air-compressor on a windmill. They use it to pump a waterwell using kind of a percolator thing in the well, but you could pump an airtank though a check valve.
  • pechan
    pechan Solar Expert Posts: 92 ✭✭
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    Re: Solar Air Compressor

    I like the idea of going the Solar VFD route with a 3 phase motor.

    Does anyone have experience with Schnider's ATV312 Solar ?
  • BB.
    BB. Super Moderators, Administrators Posts: 33,478 admin
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    Re: Solar Air Compressor

    Looks interesting... It appears to be for less than 300 Pounds out of the UK (not easy to find an online-US source with a quick search).

    If you can do this and avoid the whole Battery Bank/Solar Charging--It would be really nice.

    For a one time installation, it may be a bit pricey to "experiment"... But if this gets installed at many different locations--It is worth the time and money to get a working solution.

    Of course, there is the whole question of what you do for backup (bigger air tank, backup fuel/battery power, wind power, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • pechan
    pechan Solar Expert Posts: 92 ✭✭
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    Re: Solar Air Compressor

    Yeah the price is right for the VFD.

    If this solution pans out it would be used on several locations, so I am willing to spend some money on R&D.
    For backup, yes I was thinking of having a large air receiver tank, The wind compressors I see out there look pretty cheesy and don't look
    like they would work with the reliability required on an industrial site.

    The hick-up at this point is that the VFD requires 400-600 volts DC, which would require too many panels @ 30-40 V each.
    Does anyone know of a High Voltage panel (130~)in the 300 watt range?
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Solar Air Compressor

    Use the natural gas to run an internal combustion engine driven compressor. No worries about sun, wind, or anything else.
  • peakbagger
    peakbagger Solar Expert Posts: 341 ✭✭✭
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    Re: Solar Air Compressor

    Ormat used to supply Organic Rankine Cycle power units for gas pipeline use. Not a lot of moving parts and you could use solar thermal when the sun was out.
  • pechan
    pechan Solar Expert Posts: 92 ✭✭
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    Re: Solar Air Compressor
    Use the natural gas to run an internal combustion engine driven compressor. No worries about sun, wind, or anything else.

    That has been tried in the past with mixed results, one problem was maintenance.

    I found these panels This application would require 10 in series.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Solar Air Compressor
    pechan wrote: »
    That has been tried in the past with mixed results, one problem was maintenance.

    I found these panels This application would require 10 in series.

    Oh goody: thin film.

    140 Watts and Vmp 59.8 * 10 would be 1400 Watts and 598 Volts. Times 9 would be 1260 Watts and 538 Volts. Times 8 would be 1120 Watts and 478 Volts. Not meeting the original criteria. How much flexibility do you have on these specs? And always remember the output will not be steady or exact.
  • pechan
    pechan Solar Expert Posts: 92 ✭✭
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    Re: Solar Air Compressor
    Oh goody: thin film.

    140 Watts and Vmp 59.8 * 10 would be 1400 Watts and 598 Volts. Times 9 would be 1260 Watts and 538 Volts. Times 8 would be 1120 Watts and 478 Volts. Not meeting the original criteria. How much flexibility do you have on these specs? And always remember the output will not be steady or exact.

    Its only 200 watts above my original specs,
    Of course it wont be steady, thats the point of the VFD to slow the motor during low power.

    Do you not like thin film?
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Solar Air Compressor
    pechan wrote: »
    Its only 200 watts above my original specs,
    Of course it wont be steady, thats the point of the VFD to slow the motor during low power.

    Do you not like thin film?

    Thin film has a reputation for not being as long-lived as crystaline panels. And in some cases what it starts out as in Watts is higher, so make sure you're looking at the 'broken in' power. This does not apply in all cases because of course there are different types of thin film panels.

    200 Watts over won't matter as much as under, since panels are a current source they won't actually put out the extra current if it's not required. This might just work, even though it means you need a lot more panels than you had hoped for.
  • Ken Marsh
    Ken Marsh Solar Expert Posts: 114 ✭✭✭✭
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    Re: Solar Air Compressor

    How about other alternatives
    like using electrically actuated valves
    or perhaps flaring the waste gas?
  • rice81
    rice81 Registered Users Posts: 25
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    Re: Solar Air Compressor

    3-phase Solar Pump Inverter with MPPT and VFD

    Here is a guy who is driving a water pump with induction motor powered by MPPT / 3 phase VF PV system

    https://www.youtube.com/watch?v=wl2OMKmGjIA
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Solar Air Compressor

    Pumping water is not the same as compressing air.