Generators

[Canada]

Hey guys. I know there was a thread a while back where we were talking about these things (and pumps) and I just wanted to update my progress.

I just bought a submersible 1.5 hp mitsu, 2". and sunk it 30 metres down and tried it with my Kwai Tong 5kw gen set. At the rpms required to get good voltage and water flow, I imagine it would cost a small fortune to water the 50+ rai that I have to water this way. I wasn't happy with the water flow or the generator aspect of the plan.

I pulled the pump up, exchanged it for a 2 hp and found a generator (Chinese) that i could mate with a Kubota 9 hp water cooled. I also found a regulator that is manually adjustable (and will also split it into 110 if required.) These are what the Thais use for their "generator parties" or parades. All told, the set up cost me 50000 baht on a frame with steel wheels, delivered to my home in the woods.

Going to put the sub down tomorrow and try the new gear. It's not going as deep as the 30 metre well but I am pumping a long distance above ground, so it'll be a good test.

I'll let you know how it goes. If I can find my camera, I'll take a pic too.

D

[Familyonthemove]

Thanks for the update. Just curious why you went with the generator/motor solution? What I've seen is a mechanical screw-pump in a long pipe driven by a 'rot ty nah' mini tractor.

[Canada]

Thanks for the update. Just curious why you went with the generator/motor solution? What I've seen is a mechanical screw-pump in a long pipe driven by a 'rot ty nah' mini tractor.

They won't work on a deep well. We have one that we use on another 2 pieces but it will not pull water up 9 meters, let alone 30.

[Khonwan]

Beware that motors run more noisily with these small genies due to the shape of the sine wave, which is flattened at the peak and trough; it shortens their life. Of course, you’ll probably just have to put up with this (as I did for years).

Rgds

Khonwan

[somo]

Canada are you going to be able to irrigate 50 rai from one hole?

Presumably will be pumping it up to a starage tower of some sort first.

Would be great to get more details once you have got it all together + pics too please

[Khonwan]

I believe you’ll need 5-7 litres per square metre per day (I’m sure I was told, via fax, by a government agency over 10 years ago that 7 litres per square meter per day was required for grass pasture irrigation). At a conservative 5, you’ll need 400 cubic metres for 50 rai; assuming 24hrs/day pumping, you’ll need a flow of 16.66 cubic metres per hour. My 5kW diesel powered gen runs on ½ litre fuel per hour so running 24hrs/day would use 12 litres. At 30 baht per litre, you’d go through 10,800 baht per month. And, if that cost isn’t bad enough, I think you’d be very lucky to extract 16.66 cubic metres per hour consistently if at all. I would also doubt that 1.5HP would deliver that flow rate at 30m or so but that’s easily checked with published charts.

Rgds

Khonwan

[Gary A]

I think that everyone who has experience trying to irrigate with deep well pumps and generators will have to admit that it is simply way too expensive and will result in negative returns from just the irrigation costs. Pumping from a pond with a shaft driven pump and a Kubota is done at a fraction of the cost of a generator and deep well pump but the pond eventually goes dry.

So what is the answer? I certainly don't know and it appears that no one else knows either.

[somo]

I believe you’ll need 5-7 litres per square metre per day (I’m sure I was told, via fax, by a government agency over 10 years ago that 7 litres per square meter per day was required for grass pasture irrigation). At a conservative 5, you’ll need 400 cubic metres for 50 rai; assuming 24hrs/day pumping, you’ll need a flow of 16.66 cubic metres per hour. My 5kW diesel powered gen runs on ½ litre fuel per hour so running 24hrs/day would use 12 litres. At 30 baht per litre, you’d go through 10,800 baht per month. And, if that cost isn’t bad enough, I think you’d be very lucky to extract 16.66 cubic metres per hour consistently if at all. I would also doubt that 1.5HP would deliver that flow rate at 30m or so but that’s easily checked with published charts.

Rgds

Khonwan

Actually those figures don't seem too restrictive to me. Works out at 216 Baht/rai/month. For 5 months of the year say 1100B/rai. If I could do this for my cassava I would double the size of my crop from say 4 to 8 tons/rai giving an extra profit of around 8000B/rai. The set up costs would be significant though.

Also what would be the best way to get the water out to the land. Piping everywhere for cassava would be impratical come harvest time

[Khonwan]

I agree, Somo – I would too (and I think 3 months would be sufficient for cassava). I’m more concerned that he won’t have the flow rate from one well. More bore-holes may be required but that increases the fuel costs – wouldn’t be as much of an issue if he had grid electricity. I even think that the difficulty of laying out pipe and lifting again every year could be worth it and that the set up costs wouldn’t be prohibitive. I’m unfortunate in that I’ve drilled in three places (going down as much as 90m) and ended up with only a trickle of water (0.4 cubic metres per hour in constant use over a few days).

Canada, what is your flow rate? You may have covered this in a previous thread but, how far is the bore from the grid?

Rgds

Khonwan

[Gary A]

As near as I can figure, my 1 HP submersible with a 1.5 inch discharge driven with a 5,000 watt generator is getting about 6 cubic meters of water per hour from about 90 feet down. So far the well is recovering fast enough to sustain this flow. I was afraid to try a bigger capacity pump. Running a submersible pump dry is the fastest way to destroy it.

[Khonwan]

Sounds right to me, Gary. My 2HP pump is currently sitting at 68m (2” PVC; the bore is 90m but the pump was raised temporaily and hasn’t yet been returned to its previous 88m depth) and delivers 100 litres per minute (6 cubic metres per hour) for the first 2 minutes until the water level is pulled down to the pump – my recharge rate is useless so I can only operate the pump for a maximum of 2 minutes per hour; that’s me measuring the flow at the end of a 50mm HDPE tube that runs for around 400m and rises 20m or so (from memory) in height from the top of the bore to my water tower on much higher land.

Rgds

Khonwan

[Gary A]

I should have measured the depth of the six inch bore but neglected to do it. There's some confusion as to how deep it actually is. My wife insists it is 49 meters but I thought I remembered it being 39 meters. In any case, I had ten pieces of four meter long 1.5 inch and used nine of them. I wanted to be sure to keep the pump well off the bottom. It looks like the bore hole is pretty strong at that depth. The level from the top of the casing was about 4 meters down during the rainy season but has dropped down some now.

I don't remember numbers or exactly how I calculated the flow numbers but I did base them on filling a fifteen gallon trash container a number of times. I do remember the six cubic meter total number. It could be a little more or less.

[Canada]

Hey guys,

Sorry, I have been busy planting...and still am actually. My water problems are problems. If it is not pumps, then it is getting someone to man them because we don't yet have a good delivery system. Answer to Somo..... 50 rai one hole. Continuous job, that one. Excellent water hole. Puts out a full 2" pipe continuously. One guy waters that piece with a Kubota driven pump. Finishes, then starts over pretty much. That's what this year is looking like..... just putting out my water fires. I have not measured water output. I use terms like good, or not good, half a 2" pipe or a full 2" pipe. When I get some time, I will measure water output.

In terms of the efficacy of watering....whichever method one uses. I think you need to compare the cost of watering with the cost of not watering. Then look for the method that best suits your needs and abilities. I have seen the results of waiting for the weather to do the job. Piss poor sugarcane crops out here in Isaan. It's like they plant, water once, or till the pond is dry and walk away and hope for the best. That's fine I guess if it's all you can do. I believe there is real money in it if you are willing to risk investing a lot more than just the cost of the land and planting.

Cheers....off to the dust bowl again.