The Mind of a Greenhouse
Abstract
This is an on going project, I joined this charity project voluntarily from August to November 2018 with Wiriar Rattanansuwan, a climate engineer from Thailand. The project goal is to build a greenhouse in Nangqen, Qinhai which can resist -20Cº to -30Cº even in winter time in Nangqen. The altitude of the site is ~3,700 meters; the main task is to provide vegetable year-round for for the orphan children sheltered by the Tashi Gatsen school located in 32°31'45.2"N 96°03'05.2"E. Another main task of this project is to research a common ground for both charity project and art, science project, to innovate a transdiciplinary production system. Also I believe the innovative project collaborating with the local community will bring more attentions to the situation of these developing areas.
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Figure 1: The greenhouse installation converted from the greenhouse construction experience, the laser dyed work behind is a 2 x 2 meter cotton cloth, the content is a ten-second time spectrum generated by the Phonopaper app, and the time spectrum is from the community work video audio. Phonopaper is an open source software designed by Alexander Zolotov.
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Figure 2: The three-sided glass of the greenhouse installation is made by dye-sensitive solar technology, which is a cheap, easy-to-make, and electrode-imageable solar technology. The counter electrodes of the three pieces of solar energy are printed with trickle printing. The pattern is scanned from the calligraphy works of Cangsa Gongge, the head of the school. The photoelectrodes are dyed with the juice of black wolfberry, Taiwan sweet potato and blackberry grown in the Nangqian community.
1. Site location
Rinpoche's house in Yushu County: Tsansar Kunga, the Rinpoche, who lives in Taiwan, Taichung, which is also the founder of Tashi Gatsen School. His old home locate in Yushu which can be provided as temporary hostel. There is 3 hours driving by car between the Yushu Airport and his home. It is highly recommended that all participants should stay here for more than 3 days to adapt the high altitude (3,400 meters) before we go to school area which has very poor resources and very far away from any hospitals.
The school was called Tashi Gatsen Charity School, but since 2018 they have change the name to Tashi Gatsen Profession school after they have officially issued the school license from the China government. It takes another 5 hours by car going from the Rinpoche's house to the school.
Travels and telecom service
All international flights should transfer from Chendu Airport (CTU), the flight takes 5 hours from Chendu to Yushu. There's firewall in China so every international roaming takes VPN, therefore I strongly recommend to use Taiwan telecom roaming service. The roaming speed is as fast as when I am in Taiwan, and there's no any block in the service. The roaming fee takes ~200 NTD per day, its quite a lot but worth for short trip.
2. Design of the greenhouse
The first prototype was built in November 2018, the construction took 3 weeks. In the first phase of the design, we tried to employ many solutions and assemble them into one design. Solutions including climate battery (earth battery), pit-house, earth-sheltered design to make a passive solar house. The design of this first prototype was 4 x 6 x 2 meters in size, 2 meters deep in depth.
Pit-house: The history of pit-house can be found here. We decided to make our greenhouse two meters deep due to the extreme weather in Nangqen county. The roof frame was made of welded white iron frame and covered with transparent PC (Polycarbonate ) boards with multilayers structure, sealed with silicon. We use concrete bricks to build the walls around the hole to hold the welded iron roof on top of it. We didn't put the bricks for floors, nor give good design for shelf to store the raised beds to use the interior space in an efficient way, eventually the local people grow their plants on the floor, which is not an ideally result. Inside the house is proximately 4 to 6 degrees warmer than the outdoor temperature.
Climate Battery: For the climate battery part, we buried an PC pipe to the house, connecting the indoor space and the outdoor space, in order to drain the cold air out and circulate it back to the house after heat it underground through an 11 meters long tube. There is a toy fan I found in local vendor, it was sealed with the end of the tube inside the house. The idea was to charge it with the solar boards, so the power it collect from day time should be able to make it run over night. However the charger and battery wasn't properly set and the 11-meters long tube was way too short to heat up the cold air, personally I think this part can be heavily improved next time.
IoT Weather sensor: Unfortunately we only finished the 80% construction before my flight, I tried to install one RPI board with v2 camera module with it as weather sensor. It took me 3 or 4 days to find a local internet cafe to install Raspian. They were quit paranoid to see I was working with wires and codes in their cafe, so I quickly got kicked out. Eventually I made it done and has successfully get the sensor datas, camera vision via ssh. Unfortunately I didn’t have time to install it properly inside the house before my flight to Taipei. I use this library for the weather station.
Roof: We thought about to make the roof with glass windows but luckily and eventually I choose transparent PC with multiple layers. I am very glad I made the choice due to it's low weight and cheap price, and it was so much easier to install compare to the glass windows. However I only sliced the whole roof into 9 pieces in my design which cause a big problem for the installing, 12 to 20 slices would made the job much easier.
Roof angle and house orientation: we got the sun azimuth angle around 79º, and our roof slope should be 23º. The greenhouse is facing to south with 11º degrees counterclockwise turned in order to get the maximum sunlight.
3. The current progress of the program
The climate battery and the ground-floor Greenhouse are the two most important attempts in the first prototype. I didn't have enough time to complete the climate battery part while I was there because I didn't find a long tube locally suitable for exchanging hot and cold air. The effect of the ground-style design is good. After returning to Taiwan, locals said that in the winter, you can sweat in the greenhouse, and you can see dripping water on the roof, indicating that the temperature in the greenhouse is above zero in winter. In addition, they mentioned dizziness and vomiting after staying inside for a long time, the reason may be that only a fan is installed to circulate the air, which leads to the lack of oxygen and excessive carbon dioxide in the house.
4. A second greenhouse built near the school
This greenhouse was not built by me, construction started on April 19, 2021, and finished on May 11, 2021. This greenhouse was built by another team, the location is next to the school, I didn't know in advance, the principal Khumbu shared these photos of the greenhouse construction process with me on July 4, 2021, the structure looks very similar to our first time The greenhouse, including the design of the ground floor and the white iron roof structure, the principal said that he has successfully grown vegetables.
Figure 1: The greenhouse installation converted from the greenhouse construction experience, the laser dyed work behind is a 2 x 2 meter cotton cloth, the content is a ten-second time spectrum generated by the Phonopaper app, and the time spectrum is from the community work video audio. Phonopaper is an open source software designed by Alexander Zolotov.
Figure 2: The three-sided glass of the greenhouse installation is made by dye-sensitive solar technology, which is a cheap, easy-to-make, and electrode-imageable solar technology. The counter electrodes of the three pieces of solar energy are printed with trickle printing. The pattern is scanned from the calligraphy works of Cangsa Gongge, the head of the school. The photoelectrodes are dyed with the juice of black wolfberry, Taiwan sweet potato and blackberry grown in the Nangqian community.