May 19 – June 18: Nepal… the second month
Please see my full year trip log Sept. 2022 – Sept. 2023
Friday, May 19, 2023
There’s so much building going on. They are still repairing the damage from the 2015 earthquake that flattened a lot of the temples in Durbar Square. It turns out that Nanu’s mama was inside one of the temples when the earthquake happened and it collapsed on her. They were able to extract her with a broken hip. They painstakingly place bricks in place on the road to be covered with reinforced concrete (left). At the factory, it’s no different. There is so much going on. They shipped out the microhydro today… working right through lunch.
I skipped lunch and just heated my leftovers from yesterday’s dinner on the ISECooker. I took Nanu out for her 44 birthday. I walked her home where she lives in two tiny rooms with her two sons, her mother, and … I think other family live in other single rooms. It was fun meeting them. I video chatted with my mother, so they could all say “hi”. I was happy to receive from Jenn Klay, our department chair a picture of my research students, Orion and Stefan, presenting at the COSAM science conference.
Sunday, May 21, 2023
I visited Gem Plastics (injection molding), and realized they have some plastic pots that may be perfect for the outer shell of the ISECooker. I also visited Pranish again to talk about securing thermal storage to an aluminium pot, and conforming the stainless steel cooking surface. If it’s sloped downward about an inch, we will solve two problems:
1) the geometry will be better allowing for equal thickness of insulation around the cook pot.
2) the vapor condensation will drain rather than accumulate.
I also did some calculations… recycled aluminium costs about $1 per kg. If we can raise the thermal storage to 400 C, allowing for 300 C stored thermal energy over the temperature of boiling water. Comparing the aluminium storage to that of a lead acid battery of the same energy: the aluminium will have half the mass and cost a tenth as much. This is a simplification, because we still run a cost of adhering the thermal mass to the pot, and the lead acid battery comes with the cost of a charge controller. And the aluminium thermal storage will last as long as the pot does.
Monday, May 22, 2023
I’m wondering if we can braze the casted (recycled) aluminium STS (Solid Thermal Storage) to the bottom of an aluminium pot by placing a thin sheet of zinc in between the two and heating it to like 600 C in an ISECooker… would the metals alloy? Would the zinc migrate through the aluminium pot bottom and be present in the food in toxic concentrations? Questions to answer.
I stopped in the morning at the factory, took Pranish a piece of stainless steel, and worked on my bike a little. Now 12 of the 21 gears work up from 4, and I removed the kickstand that opened every time I hit a bump. It still needs some work, but it’s way fun riding around town… “stay on the left!”… “remember that no one looks behind them. It’s your responsibility not to hit anyone, there is no right of way.”
I gave a presentation at Tribhuvan University Engineering today (Talk Announcement). I outlined the evolution of our project, finishing with a recognition that here in Kathmandu, we have everything we need for successful manufacturing and dissemination… except a university partner, adding at the end that I was challenging them. Three students approached me afterwards eager to talk. With many of my answers, they interrupted me saying something like, “I know that because I read your paper,” or “that was on your blog,” or “that’s in the construction manual, so I get it.” Wow, they must have spent hours preparing for my presentation. They have a year-long masters thesis project that they do in groups of four, much like Cal Poly does with our senior in mechanical engineering. I gave them a few of the challenges – in particular to figure out a way to physically and thermally adhere a mass of aluminium to the outside of a pot… I imagine how cool it would be if they take on that project and I join them with a group of Cal Poly ME students doing the same.
The talk was fun… and the questions were provocative. People are pretty skeptical about changing the way they cook or adopting a different cooking method. I consistently respond that we all change the way we cook, but we don’t have to do it absolutely: “I didn’t throw away my range when I got a microwave oven.”… and :if ISECooking replaces 60% of wood/charcoal use, isn’t that winning?” Another group of students asked me for advice about how to go about doing solar thermal energy research. They took me to two skeletons of Scheffler Reflectors. Reading about Scheffler Reflectors, I’m struck at how similar my approach is to Wolfgang Scheffler:
“During the whole time of development of the Scheffler-Reflectors – up to now 23 years- care was taken to use simple materials and construction techniques common for rural settings. For that reason Wolfgang Scheffler did a great deal of his developments in Kenya and India where he learned local construction techniques. Together with local craftsmen he built a number of first solar kitchens and installed them at interested schools.”
Let’s do a comparison… Scheffler’s succesful installation:
“A good example is the construction of the worlds largest solar-kitchen in Abu Road, Rajastan, by the Brahma Kumaris. Because they did most of the work involved themselves, the whole installation ( 800m² of Reflector surface + steam system + back-up boiler) could be built for only 100 000 €. As they cook for a maximum of 18 000 people this equals 125,-€ per m² or 5,5 € per person.”
125 Euro per square meter is a good metric. I’m estimating that they are able to harness sunlight with 50% efficiency indicating 125 Euro per 500 W, or about 40 cents / Watt. This is about what solar panels are selling for right now…. and getting cheaper. This week, I bought two solar panels for 45 cents a Watt. But you still have to buy the ISECooker, although the expense is less than the solar panels. Additionally, there are so many other convenience issues. There are massive economies of scale that can be leveraged when building a cooking facility for thousands of people. Ultimately, I had questions for these three students. How is it that these Scheffler Reflectors were perfectly set up for and integrated into their kitchen, and they’ve fallen into this sad state? Where did they hope their research would go? What would success look like? The answer to that question should guide their choice of research topics.
It was so fun.. rewarding to be with students again. I’ve missed it a lot.
Tuesday, May 23, 2023
We got a new heater from Hari that hopefully has high enough resistance to give us low power potential to do a 30 W all day simmer… we need about 1600 Ohms. The measured resistance is ~500 Ohms, so three of them together would work fine. However, there is not enough space for all three to fit – they are too long. I will have to wait to find higher resistance wire to make my own coil.
Thursday, May 25, 2023
Holiday today, and Bikram told me there would be a celebration around 4:00 near the central zoo… but he wasn’t going because it was a crowd. He would be right, but I didn’t have a lot going on anyway, so I went down and hung on a fence for about 45 minutes with some boys, trying to figure out if “it” happened yet. No marching band or fireworks, some traffic conflict, some people in uniforms and then people started leaving… was it because it started raining? It wasn’t raining heavily, but I decided I had enough, even if I was going to miss the celebration.
I asked Bikram what was supposed to happen. He told me the story of the vest and asked if someone showed a shirt. As I recall, I think someone at the base of the large monument (on wheels that looked a little like a Christmas tree) did hold up what looked to be a shirt. Now that I understand, I still don’t understand.
Before I went to the celebration, I had a video call with Vimal and Nick from Delhi and England, respectively… where it’s not a holiday. We agreed that this short ISECooking summary adequately describes my project and can be forwarded liberally.
Friday, May 26, 2023
I wrote an essay On Ownership and Failure, for the students in 391, Appropriate Technology, arguing that your project in a developing country is destined to fail because it is your project. The key to supporting a successful project is to support their project. The most obvious solution is to support a project that you value that is already on the ground in motion. Is it possible to introduce an idea that will become their project? Certainly, it’s hard and unusual: Certainly there are far more examples of failed attempts.
I’ve felt isolated lately… I haven’t found community in Nepal despite the people here being profoundly kind, gentle, and patient. It’s brought me down personally. Recently, I’ve recognized this isolation (and same feeling) professionally. I have arguably seven collaborators (five companies and two NGOs) that have been supportive in giving me what I need and providing positive feedback… but every action is initiated by me. Clearly I own the ISECooking project. I had throught Bikram (owner of NYSE) would own the project, but he is busy with many projects and simply supports me when I ask for something. Bikram and I spoke today at lunch. I expressed my concern about ownership and he agreed that the project needed an owner here. I asked who “owned” the insulated water heater project he is engaged with, see April 21. “It is RERL, Satish.” I asked about what will happen with the ISECooker project if it is successful. He responded again, “Satish.”
I sent an Email to Satish expressing my concern and then again a week later. Please see the correspondence where they identify this as my project but outline how they support it.
Saturday, May 27, 2023
Oh WOW, have I ever been sick. ~ 3:00 AM I woke up and until around mid day was sicker than I remember being at least since ~ 10 years ago?, Alex brought some kind of bug from her Santa Barbara friends to the Live Oak Music Festival (when it was still at Live Oak). Until about 11:00 AM, I had stomach ache, nausea, and fire-hose diarrhea…. too much information? – you’ve been there before too, no? Sorry, no pictures. I had dinner at a tiny shop in the alley and drank from the plastic bottle of water they had on the table… that’s my best guess: it wasn’t bottled water, or the bottle itself was contaminated. I’ll drink my own water from now on. I managed to do yoga just before noon, and then slept until about 2:00. Still laying low. Hoping to be back in action tomorrow.
Sunday, May 28, 2023
Feeling healthy, but weak. Met with Pranish and we visited Buddha metals (Niran: +977 985-1054324), an aluminium foundry just around the corner… I hadn’t noticed it was there because they just moved there and still haven’t changed the sign on the front.
We returned to Annapurna Household Appliances (AHA). I saw how they make aluminium pressure cookers… amazing how they shape oval holes and tops. We also tried to shape the stainless steel cooking surface to be peaked in the middle to allow the cooker to sit higher in the insulation and to allow the condensate to flow outwards… it didn’t go so well. It was great to see how everyone… like four workers, enthusiastically engaged in efforts. They’ve never worked with SS before, but have recently applied for license to shape SS as well as aluminium, so everyone is interested to see how SS behaves. There will be new challenges.
Monday, May 29, 2023
So, what needs to happen by when and for what?:
In order to compare the ISECooker performance to that of an induction cooker, (next week)
1) I need a lower power heater. From Wednesday May 10 data, we see that at 120 C, the ISECooker will lose heat at a rate of 20 W, so 25 W would be more than enough to keep food boiling without losing any appreciable amount of water.
In order to demonstrate ISECooker STS (Solid Thermal Storage), that RERL and PEEDA requested,
2) We need an aluminium puck and a way to thermally secure it to an aluminium pot. I am no longer going to advocate for using a pot made from cast recycled aluminium because of concerns over toxins in recycled aluminium (see section 8 of the construction manual). However, the aluminium STS can be cast from recycled aluminium and then attached to a spun aluminium pot. We’ve found that putting the two in contact provides poor thermal connection, so the power delivered from the stored power is pretty low (~ 300 W) if the STS and pot are not one single piece of aluminium. So, I will try to weld or braze the aluminium STS to the aluminium pot. I’m going to try joining them by melting zinc (melting point 420 C) between them.
3) We need to replace the Teflon cover with something that can get hotter than 300 C. Teflon at 300 C produces lethal toxins (section 7 in construction manual). Ideally, we should be able to buy inexpensive stainless steel foil… maybe 0.002″ thick, made in India.
In order to make this a safe and desirable consumer product
4) We need a way to change the power both from a solar panel and from grid.
5) The solar panel ISECooker needs USB port charging capacity because if people don’t have electricity for cooking, they probably don’t have electricity for lighting and cellphone charging. Possible accessory is small charge controller and battery.
6) We need a high temperature turn off to prevent the ISECooker from destroying itself or starting a fire if it overheats.
So, why do I find earthworms in my bathroom? How do they get in? It’s only three times so far, but there is no access to the earth? Do they come up through the sewer (disturbing thought), or find a conduit through the foundation? I am on the first floor. They certainly don’t come in from the outside and slither across the carpet into the bathroom. Their fate is simpler than their source: I fling them over the back fence into a garden, where I’m certain they have a better life.
I bought 200 g of Zinc… delivered today by motorcycle for $1.20. It’s a chunk of the thick sheets the company sells.
Tuesday, May 30, 2023
Today, I received my two (5 kg) aluminium STS (Solid Thermal Storage) pucks (D=7.5″, dH=2.5″) from Buddha Metals, picture, above, right.
Wednesday, May 31, 2023
We are ready to make our STS prototype, and Bikram assigned an intern, Samjana, to work with me. We spent the morning machining the STS smooth (or mostly watching Ashok do it, as I’m not familiar with this lathe and it’s been 25 years since I last used one), learning about the project, and planning the prototype. The problem is that with the extra (almost 3″) of height introduced by the STS requires some accommodation in the insulated chamber. We can make the lid an extra deep tub and spot weld a stainless steel top surface that is contoured over the pot, or we can get an very short pot. We’ll try both approaches.
Of the action items from Monday, on 5) and 6) have not yet been addressed. We are doing pretty well with the rest of them.
Thursday, June 1, 2023
Up ~ 4:00 AM with stomach upset and acute diarrhea again… but not as severe as Saturday. I rolled out of bed around 1:00 PM, did some yoga and went to work. I spent about a half hour at work… incredibly effective. I took the STS and Samjana to AHA to ask Pranish for special pots to accommodate the STS, and I spoke with Ashok and Bikram about how to make a stainless steel surface to fit over the cookpot, separating the insulation from the cooking area. There’s a litter of fluffy puppies next to NYSE. I gave them my leftovers from yesterday…. I’ve lost my appetite. They were all over it. It was a feeding frenzy, yet my hand was never bitten. It was cute to see them covered in pureed spinach afterwards. I hope they lick it off each other.
Friday, June 2, 2023
We built a deeper insulated lid that will allow us to use longer pots (or pots with a thermal storage under them). The present prototype has a (blue) flat cap for shorter cook pots, and a deeper (green) recessed cap for taller cook pots… including the normal size cook pot with thermal storage.
Saturday, June 3, 2023
I ran with the Himalayan Hash House Harriers (HHHH)!! The hash was several miles south of Kathmandu in terraced hills… 10 km. It was the first time in years that I’ve run more than 100 m… I was so pleased I survived.
We ended running down the pipe of Nepal’s first hydroelectric facility… 110 years old. I understand it’s the second hydroelectric power station constructed in Asia.
Sunday, June 4, 2023
I’d met Bashraj several weeks ago, a first year business student. He approached me in Durbar Square to ask if I’d answer questions for a survey about home stays… and as I’m staying at a home stay, I agreed. Afterwards, I told him about what I do and he said I should visit the National Innovation Center I(NIC) at Tribhuvan University. This morning I got a text from him saying we should to today… so we did! Wow, an incredible center of resources – institutional, people, and machines. Dr. Mahabir Pun, studied in Wisconsin… runs this place. They are developing fixed-wing drones to deliver medicine to remote areas.
3-D printers, solar driers for food… or anything else. All kids of machine equipment including a plasma cutting bed…. they’re building a wind tunnel.
They are also studying the cooking challenge with infrared cook tops, honey bees, aquaculture, farming machinery, and traditional Nepali metal work.
It turns out that a few weeks ago, Dr. Pun called for a sit in on the Nepali government demanding that they allocate 1% of the national budget to support innovation. After three days and nights of 700 – 800 demonstrators, the government agreed.
I’m giving a talk at the NIC Friday at 10 AM.
Then we went to the Tribhuvan Physics department. The chair is interested in physics education research and we will discuss collaboration opportunities.
Monday, June 5, 2023
As things come together for the prototype presentation, we refine the pot and nest designs. We went back to AHA to improve the pot shapes and they found a new die… maybe an old one? Straight tapered, so the pots will fit perfectly into the nests. And they made some extra long to accommodate the heater, and a few extra short to fit in a smaller “clam shell” design… and they made rounded rims for the pots to accommodate the steel cable handles, and extra flat rims for the nests to seal to the stainless cook top with rivets. I have immense respect for craftsmen/artisans. This guy is such a badass… he is so a master of what he does… confident, but careful and wise. Always listens attentively.
What we really want is to have the entire cook top surface and nest to be the same piece of shaped, thin stainless sheet. I asked him if he could spin such a surface from our 0.5 mm stainless sheet. He said, “no”. I asked if he’d be willing to try if I brought over a sheet for him to mess around with. He’s game. Everyone there is curious about stainless steel because they are planning to begin work on stainless steel pots.
…. Another microhydro prepares to ship out to West Nepal from NYSE.
Tuesday, June 6, 2023
I bought new plastic basins, anticipating the “clam shell” model first prototyped with Clement in Zambia. I bought four basins – two different kinds. They have the same depth, but one set is 2″ wider. This will make them better insulating, especially because about half the heat loss will be via the two stainless steel surfaces…. but the smaller ones are a little cuter and slicker. There is also the option to have the base be an aluminium pot from AHA, but this would likely cost an additional $10…. these are all options to put in front of RERL.
In addition to demonstrating the prototypes, RERL needs a quote, so I’m going back and pricing out all the things we bought, and I’ll meet with Bikram to estimate processing costs.
Most of the ISECooker building is being done by intern Samjana, under my supervision. We are finishing the second 5 kg aluminium STS. I helped her set up the lathe the first time and she did the rest of the machining by herself… declining help from the well-meaning men in the shop. Whenever we visit AHA, she is attentive to learn. Below, Bikram sent me a clip from one of the many surveillance cameras displayed on a large monitor in his office.
Wednesday, June 7, 2023
Oh, so frustrating day, breaking NiCr wire heaters trying to twist the ends into low resistance electrodes that won’t corrode… until Ashok says, “I think this wire is hard, if we heat it, then it will be soft.” But they didn’t have to do that in Addis Ababa… but maybe we do… So, we heated the wire with a torch and it was easy to twist.
Thursday, June 8, 2023
I have breakfast almost every morning at the same little family booth. It’s warming to watch mama get the little girl ready for preschool. She doesn’t cooperate, but it is clearly evident they both enjoy the process. I got my hair cut in the evening. It costs $3 – $5. However, they charge you $10.00 for the subsequent massage that begins somewhere before the haircut is completely finished. I didn’t say anything last month… it could have been close to an hour, and it was a little brutal, cracking my neck and beating on my head several times. This time, I said, “no; good; I am done.”… but I had to repeat that twice more. Then he finished the haircut and I left.
We are getting close to a commercial consumer product…. Samjana demonstrates:
Friday, June 9, 2023
I gave a talk at the National Innovation Center I visited Sunday. I was very impressed with the 30 young technical people who attended… and there were 30 virtual attendees on Zoom. After my talk and answering a battery of questions, I spoke with Jeevan a recent graduate developing a high efficiency infrared cooker for the Nepal market. We have a lot of reasons to work together.
Then I rode my beater bike all over Teku shopping for the hardware I need to finish the prototypes. I found only one shop… a tiny shop, that sells the small screws we need.
Saturday, June 10, 2023
If last week’s hash in the hills was the most beautiful hash, this week’s was the ugliest, through downtown Kathmandu, boasting the world’s worst air quality. 14 km of running through the city… and I got lost. I guy ran by me and I kept up with him for a time… then realized he wasn’t a hasher. It was the first time I’d seen a regular person running on the road. Anyway, no cell phone. Had no idea where I was. I didn’t even know where I needed to get to. It was getting dark. I was out of gas. I was scared. I hated hashing. I started asking people if they had a cell phone. I finally found a man that had google maps. I traced my path from my home to where the hash began (and ends)… and then asked him where on the map we were. He didn’t. Few people can read maps. When I arrived at the “on-in”, they were well into the after-party and asked what happened to me. I responded that the trail was so much fun, I did another loop.
Lying on the ground, I became acutely aware of an overwhelming smell of urine.
Sunday, June 11, 2023
Today at the factory, we had no municipal water, the electricity went out, and we ran out of drinking water. After a few days of not flushing the toilet, it makes a nice place to breed mosquitoes. Feeling at quite at home… just like Malawi.
Monday, June 12, 2023
Major event yesterday… lots of failure, and learning.
We tried to melt the aluminium STS to the aluminium pot by putting some Zinc between the two and raising the temperature inside the ISECooker. We had 3 thermocouple sensors: between the ceramic heater and the bottom of the aluminium nest, against the aluminium STS, and under an iron weight inside the cook pot. When we plugged in the heater, the power shorted to the body of the aluminium nest and immediately melted the thermocouple leads to the data logger, and fried the data logger. I’d electrically tested the power to be insulated when we assembled it, but we’d moved it around a little since then. Samjana and I put the thermocouple leads back together with new insulation and improved the fiberglass electrical insulation around the electrical power cables. We measured the temperature with the remaining hand-held Thermocouple reader… which we soon learned would not read temperatures higher than 400 C. I extrapolated the data… that when the temperature of the cookpot reached 400 C (and turned off), the temperature under the heater would be about 600 C… well below the 660 C melting point of aluminium. I expected to see a rapid rise in temperature of the cook pot as it neared 400 C, as the melting zinc (420 C) would thermally connect the cook pot to the STS.
I was wrong.
We turned the power off yesterday shortly before 5:00 quitting time, and left the (mildly smoking) ISECooker in the middle of the shop, away from anything that could burn. The entire container was too hot to touch, maybe 70 C. This morning, the temperature of the STS and cooker assembly was 74 C. We opened it up outside… in case there was any toxic vapors. The stainless steel surfaces were discolored and softened: likely both tempered as well as covered in some product of the out-gassing of the rock wool. Some of the Zinc had melted, but adhered to the aluminium in only a few places… the STS was not brazed to the cook pot. Part of the STS had melted onto the ceramic heater, and the bottom of the aluminium nest melted through, leaving a hole in the bottom and a blob of aluminium. The rockwool worked well and was only discolored. The fiberglass insulation around the NiCr wire was brittle enough to disintegrate upon touching.
Feeling of failure… I cut corners to save time on two occasions: I should have tested the heater for a short, again, before connecting it to power, and I should have turned off the heat when the thermocouple thermometer stopped reading over 400 C. I also failed to measure the current to the heater, because we have a hand-held AC current reader that simply clamps around one of the power leads. I connected it today, to see that the initial current was 5.6 A, and reduced to 5.4 A when the NiCr was red hot, indicating increased electrical resistance with temperature. If I had been measuring current yesterday, it would have provided some information about the temperature of the NiCr heating wire.
There are (also) some positive takeaways…
1) Primarily, that no one was harmed… There is merit in the precautions we did take. Additionally, the failure (in that the temperature got too hot), provided way more important information about the resilience of the materials to high temperature.
2) The ceramic heater used was 1500 W. Judging from the way the temperature rise tapered off at higher temperatures, the 2oo W – 300 W power we plan to use would never raise the temperature of the ISECooker even close to the aluminium melting temperature. If this is true, (and I’ll test this very carefully,) a simplified 300 W ISECooker could be made without a temperature controller. We initially estimated the thermal conduction of the ISECooker to be 0.2 W/K, meaning that 200 W would raise the temperature of the cooker 1000 C higher than that of ambient. However, insulation effectiveness drops off at higher temperatures because the air molecules are moving faster. The data below indicates that the thermal conductivity of the insulation (rock wool should behave similar to fiberglass) approximately doubles between room temperature and 230 C, and increases by a factor of 4 a little below 500 C. All the same, the experiment begging to be done will be to apply 200 W for an extended period of time in order to find the asymptotic temperature… next experiment.
Metals also become more conductive at higher temperatures, but in a less dramatic and more linear fashion.
3) The fiberglass insulation around the assembly uniting the (red hot) NiCr wire with the high temperature, fiberglass insulated power leads disintegrated only until about 3 cm below the bottom of the ceramic heater, indicating it may be fine for powers of 200 W – 300 W. For the high temperature wire, the fiberglass insulation is still intact, although the underlying material (likely Teflon) disintegrated for an additional 5 cm.
In short:
“you never know how much is enough until you’ve done too much”
We have a very good idea of limitations now. ISECooker was never intended to run at 1500 W. We only did it yesterday to melt the Zinc. The bad news and good news is the same:
A 300 W ISECooker will not attain extreme temperatures… let’s estimate the asymptotic temperature we would have had with a 300 W heater. Power loss is proportional to the product of the temperature difference (Cooker – Ambient) and the thermal conductivity. I assume that with 1500 W, we were able to attain a temperature of 680 C. If so, I created the graph at right taking the thermal conductivity as indicated in the graph above. With 200 W, temperature should asymptote at 270 C, and with 300 W, temperature should asymptote at 320 C. On Friday July 21, I again melted a pot with only about 200 W… proving myself again wrong. It appears that the insulation works better than I thought it would.
Next steps: Replacing the melted heater nest (AHA is making a replacement today), looking for someone to weld the aluminium pot to the aluminium STS, and repeating the experiment with 200 W and 300 W.
Tuesday, June 13, 2023
I visited Belaju School of Engineering & Technology in northeast Kathmandu. This is where Bikram got his diploma. He found someone there who can weld aluminium. After I refinished the surface on the partially melted STS on our lathe, I took a taxi with the two STS and three pots (in case we destroyed one) to meet Dinesh and his partner, Dipsom (they weld together and jointly own a restaurant in Patan). After a little bit of figuring things out, Dinesh nicely welded the pots to the STS. The weld did result in a ring of melt and recrystalization around the base of the cook pot, although everything seems sturdy and intact.
I liked their interest to learn. This was evident in the way they went about the welding. But even before they started, they asked me all kinds of questions about the project, and I showed them some videos. Additionally, afterwards, Dinesh asked me to forward him a video about using Zinc to braze aluminium and will experiment with the technique. I paid him a total of 2000 NRs (~ $14), but he said that if I had many of them done, it would be less expensive
Jeevan (see Friday, June ) and his friend, Sapan came in the afternoon to learn about our project. They insisted we put it together for solar electric cooking. The sun didn’t cooperate. We had dinner together and discussed opportunities. Jeevan has expertise in circuitry and automation. He reminded me that we can attenuate AC power by using a phase shifter… we don’t need multiple heaters for the grid connected ISECooker! He has been making these phase shifters, and will get me some… they cost about $2. And, Jeevan may be interested to “own” the project when I leave and continue innovating … virtually with Cal Poly students.
I went out into Durbar square in the evening with my guitar, and sat on the corner of a temple where there was a crowd of people, and kids building parkour skills. It’s pretty much a silent serenade, because I have to wear ear buds in order to hear it myself… AND I am not yet good enough to want the sounds to be audible… but I enjoy being able to play and also be outside my room. I did this last night, as well, and no one talked to me. But tonight, Deenesh jumped next to me, enthusiastically showing me his Pink Floyd tattoo, and asked to play. He said he wasn’t very good, but blasted off some songs he’d learned on YouTube… introduced me to his wife and siblings… did some Beatbox… and disappeared.
Wednesday, June 14, 2023
Samjana and I rebuilt the damaged ISECooker, improved it, and built two new electric heaters. I was able to twist the NiCr wire into a somewhat low resistance lead, and insulate the lead by stripping the insulation off “heat-proof” wire and slipping it onto the lead, securing the power wire (the same “heat-proof” wire) and sliding a fiberglass sleeve over the whole joint. Additionally, we drilled holes in the ceramic heater to screw it down to the bottom of the heater nest. The holes in the bottom of the aluminium heater nest for the power wires are oversized, so even if there was exposed wire (which there ISN’T), it wouldn’t short because the wire is constrained away from the metal by the ceramic feedthrough holes.
The heater for the solar panels is separated into 3 parts, allowing the resistance to be 8 Ohms, 16 Ohms, or, 32 Ohms, depending on where the power is connected. I describe in the construction manual (section 5) how switching between resistors optimizes power from the solar panels. Marcorios and Ropa, back in California, are building a circuit to engage the correct heater segments.
Thursday, June 15, 2023
Visited St Xavier Secondary School as Krishna’s guest.
Spent the afternoon frustrated, trying to wire a 3-resistor solar panel ceramic heater to the ISEC shell… And realized I should just do what Asok tells me to do. He is so good at building things.
Friday, June 16, 2023
Asok, Samjana, and I assembled the solar ISECooker in short time, and assembled another smaller, plastic ISECooker for 250 W (220 V AC).
We also tested both of them. They work flawlessly. The solar cooker above has three different heaters for different solar intensities that a person can switch, as explained Wednesday June 14. A smaller one below has a 250 W heater, which we will be able to attenuate down to 25 W (Explained, Tuesday, June 13). I did a test today, heating the 5 kg puck to 250 C, and boiling 1 kg of water in 41 seconds, with the stored heat, corresponding to an average thermal power of 9 kW. Please see the video I just posted on YouTube. In Togo, we did a similar experiment, boiling 1 kg of water in about 3 seconds, corresponding to about 100 kW of thermal power. The ten-fold reduction of heat flow is because in Togo, the aluminum pot and puck were cast as a single piece, where we are spinning pots from commercial aluminium and welding it to a 5 kg puck of recycled aluminium from a local foundry.
In the evening, I went off on my bike to an art opening, then a drag competition (which– hello, Texas– is still legal in Nepal) at the Hard Rock Cafe in Thamel. I met some hash friends for dinner, and we went off to a gay bar, but didn’t stay… it was sweltering. So, we sat at the rooftop cafe. My first night out in two months… just to remind me that it’s just fine to go to bed early.
Saturday, June 17, 2023
Tried to run a 10k hash up in the North– the foothills, Bardal Inn Resort, Shivapuri. Jeanne wanted to ride our bikes there, because it was only 24 km away. The last part, however, was all switchbacks. We ditched our bikes at 20 km because it was steep enough that pushing them was not worth it. After a km of walking, we got picked up by a car that was also late… yes we arrived late. By that point, I was done… like “just a beer and dinner please, no hash necessary,” but the faster group had already begun, running up and down the hills, and I took off after the walking group… which it turns out was as hard as a regular hash run in the US. I saw the group ascending a valley on the opposite side, so I took a short cut down to catch up, and it was steep… I fell off escarpments, several times to my death, but somehow rallied… the sweet sting of nettles took me right back to the Princeton Hash House Harriers.
After the hash, the singing and beer… and there was food. It was getting dark, and we rode home. My crank arms started coming loose and I lost several gears for reasons I don’t know… a little adventure: just what the weekend ordered.
Sunday, June 18, 2023
I woke up ready to go to work, but became sad hearing a Father’s Day broadcast on NPR, realizing that neither Tekuru or Neil had sent me a message… and it was already evening in the US! Still, my higher self said, “just reach out… let them know you love them.” Then, Tekuru pointed out that it wasn’t Father’s Day yet… I still haven’t internalized that Sunday is a working day in Nepal… Every week, I think that it’s Sunday when it’s really Saturday, because we work the next day.