Thursday, November 14, 2013

Research findings from my thesis work

In my last post, where I shared my thesis, I promised you a short summary of my research findings. Here they are. (Well, some of them, anyway.)

First, a quick reminder of the research issue: In eastern India, ~85% of farmers irrigate their land using fossil fuel-powered pumps because they do not have access to electricity. Diesel and kerosene pumps have very expensive operation costs that farmers cannot afford, so they often choose not to irrigate outside monsoon season. With few other livelihood options, they migrate elsewhere for work. When they migrate seasonally, their families often cannot access social services such as health and education. I sought to address this challenge by developing an alternative off-grid pumping solution.

(Please do not confuse this with the opposite irrigation problem in western India, where free or near-free electricity for agriculture has led to unlimited pumping and severe over-exploitation of groundwater resources. The water table is not falling at a dangerous rate in eastern India. In fact some people argue that increasing groundwater extraction would reduce the incidence of flooding during monsoon season, because the soil would not be as saturated.)

For more about irrigation economics, see an earlier post here.

And now for my favorite research findings:

1. Rental costs are greater than fuel costs. This one actually surprised me. Everybody loves to talk about dirty fossil fuels and how the high cost of diesel (or in this case, kerosene) is what's keeping poor farmers from irrigating their fields. But I tested the actual performance of some pumps owned by farmers in Gumla and found that the flow rates were so bad that farmers needed to rent the pumps for an absurd number of hours to soak their fields--and hourly rental rates are fairly high. The implication? The focus of designing a new pump should be on increasing the flow rate more than fuel efficiency. The faster the flow rate, the less time it takes to irrigate a field--and the fewer hours required to irrigate, the less a farmer spends on renting a pump.

costs to irrigate one acre of land with 2" of water with a 12 year old Honda pump

2. Eliminating, or at least significantly reducing, suction head can reduce operation costs by up to 44%. I ran an experiment to test the hypothesis that eliminating suction head would increase efficiency and flow rates--and the experiment verified this hypothesis (see chapter 2 of my thesis). I then spent a great deal of time during my master's research trying to come up with affordable ways to run a submersible pump with a surface engine (see chapter 3 of my thesis), only to be outsmarted by the farmers (as usual): see #3.

3. Farmers already know #2. It turns out that farmers have already figured out that reducing suction head increases the pump's efficiency and flow rates (apparently, they experiment with lowering their pumps once the groundwater level falls beyond 7 m, the suction capacity of a pump, during dry season). Some lower the pump into the well with a rope, while others dig a trench next to the well:

4. Indian pumps are super leaky, but farmers know how to deal with it. I couldn't get an Indian pump to suck. Period. I tried a million ways to plug the leaks and just couldn't do it. That is, until I met a bunch of farmers who laughed at my teflon tape and showed me how it's done: slash an old bike tire and wrap those strips of rubber around all pump connections and hose fittings. Jugaad at its best! (But seriously, this is a problem the Indian pump industry desperately needs to address.)

5. Farmers claim Chinese pumps are more efficient than Indian pumps. Nobody knows why or if this is even true. Unfortunately I was unable to test a Chinese pump (I couldn't get them to work at MIT, and the villages I visited didn't use them--I would have had to go to West Bengal, and I did not have time). By taking them apart, I learned that they use a 3" discharge hose, rather than the 2" hose that Indian pumps use, and they have a smaller impeller-to-chamber volumetric fill ratio. The larger hose diameter makes sense to me: larger diameter = fewer pipe losses = higher efficiency. But I'm not sure how impeller-to-chamber volumetric fill ratio might impact efficiency, and I would be interested in exploring this issue further in the future (especially because I'm fairly certain Chinese pumps are going to take over the eastern Indian pump market).

6. Women don't touch engines. This one is not surprising. I heard from both men and women in the villages that "machines are for men" (though one women did pull me aside and asked me to show her how to start a pump engine when her husband wasn't looking). Women came up to me while I was testing the performance of their husband's pumps and asked, basically, "What about us? We're stuck with a bucket and rope. Our husbands may use a greater volume of water with their 'paani ki machine,' but we use water more frequently." To be honest, I had considered domestic water supply a completely separate issue from agricultural water supply, and I thought improving irrigation would increase the wealth of the entire family and thus benefit women too. But if I'm working on water supply anyway, why not think about a multi-purpose pump?

7. Manual rope pumps intended for irrigation end up utilized for domestic uses. Manual rope pumps have been installed all over the world as part of various water programs. In many cases, such as in rural Orissa (in eastern India), the pumps are intended for irrigation. Well, it turned out that in Orissa, the pumps were not used for irrigation. Irrigating a field requires a huge amount of water, and manually pumping that volume of water is time-consuming and exhausting, especially in the heat of the dry season (temperatures can soar to 50 C/120 F). Instead, it turned out that women used the pumps for domestic purposes: drinking, cooking, washing. The women love the rope pumps because they are way easier to use than throwing down and raising a bucket. Plus, children and the elderly can use a rope pump; otherwise they need the women to fetch water for them, since they are not strong enough to raise a heavy bucket of water.

8. Farmers like the color green. This is maybe a silly one, but farmers associate green with agricultural productivity. PRADAN, the grassroots NGO I worked with, told me that whenever possible they use the color green in their products and services, because the farmers respond better to it.

So, what did I do with all of this? I designed a dual-mode rope pump. The pump can be used in motorized mode for high-flow applications such as irrigation and in manual mode for low-flow applications such as domestic uses. The engine is removable, so it can be safely stored at home (farmers expressed concerns about theft) and one engine can be shared by or rented out to several wells, as is done now with the regular centrifugal pumps. Plus the men have no problem allowing women to use the pump in manual mode (the hand crank is removable so it doesn't injure someone when the pump is operated in motorized mode). And yes, I painted the pump green.

Below is a video of the pump in action, being tested by users. I got pretty good feedback from the users, and I have some ideas for future modifications.

Speaking of user testing, I employed human-centered design methodology throughout my research process. Here's a video explaining what I did:

Ok, so maybe this post wasn't a very short summary.

HUGE thank you to PRADAN and Swastik Engineering Works for their support. I could not have done this project without them.