4.3.3. Appropriate Tech

Ok, let’s have some fun with this! I’m going to share a series of photos with you of various types of “appropriate tech.” See if you can spot how well each of these meets the four criteria. 

Using the waste stream

Pallets are a waste product that have so many uses. How about a balcony salad garden?

Holes are cut on each side of these bottles to water them and access the plants, which can grow outside of the holes when big enough. Imagine this on an apartment window. Daily fresh salad and herbs! 

An earthbox is a container garden that waters itself. It works because dry soil will “wick” water - moving it through the soil to areas of dryness. Roots do this with even more efficiency. So by putting some soil in contact with water stored at the bottom of the pot, one can keep plants watered to the degree they need it, passively.

The water container in these usually holds enough water for about 2 weeks or more of watering. Do you live in a townhome with lots of potted edible plants, and you want to travel? Get some of these, or create them yourself. 

Do it yourself. In this version, no pipe is used to add water - it is added from the side hole with a nozzle or funnel or ? (be creative!)

I’ve created many of these for myself and others with old plastic containers lying around in a garage or closet, using the basic principles. I’ve used a single-use plastic cup with some small holes in it to connect the soil with the water. I’ve added a brick or rock, to prop the top bucket higher and add more space for water. Once you understand the principle, you can design this yourself. A purchased Earthbox costs more than $100. Every one of these I’ve made has been from “waste” materials lying around. 

A bicycle blender. Why not capture the energy used to exercise and make a delicious smoothie to drink once you’re done? Using wheels to create energy is an old technology. 

These bicycles at Solar Living Institute power lights and chargers.

Water Filtration

 Knowing the basic principles of filtration and some low tech approaches can be life saving. Our project in Haiti after the 2010 earthquake included education on how to safely filter water with appropriate technology. There are many ways to do this; we share a few here. 

This method kills pathogens in water. We used this as one of the ways to filter water in Haiti.

A sand filter can be built in an emergency (or purchased; there are many versions) that removes 98% of pathogens. An important component is the biological layer at the top, where friendly bacteria that help kill the pathogens reside. This is only about an inch deep or so. The rest of the sand has no living biology in it because it is packed tightly enough that there is not sufficient oxygen for pathogens to survive.

This also removes other particulates and creates water that is clear. 

Many living substances, from banana peels to apples to coconut husks can help remove particulates and pathogens from water. This photo depicts an experiment where crushed moringa seeds were used to very turbid water from a river. Moringa seeds have a “flocculant” capability, meaning they attract particulates to them which then settle at the bottom of a container with the seed powder.  This, as well as simply letting turbid water sit so particles can settle, can be used before using a sand filter, to ensure the sand filter lasts longer before you need to change the sand. Or used on its own as properly used, moringa seed has removed 97% of pathogens from water which greatly increases the odds of avoiding water borne diseases.

Moringa grows very well in tropical and subtropical areas, where some of the worst water filtration problems and water borne disease rates exist, is very fast growing (can seed within the first year), and could be an important part of water filtration in those regions. This is not guaranteed to remove all pathogens but could be life saving in an emergency situation.

https://www.tsijournals.com/articles/a-case-study-on-low-cost-water-treatment-using-moringa-oleifera-drum-stick.pdf

“Maker” ethos

The Maker network is a growing network of people who devise creative solutions to solve problems, using whatever is lying around. Make Magazine, which shares some of these solutions, has a challenge in each issue, where you are provided with some pieces of junk and some natural resources that you then must use to solve a technical problem. The solutions are often brilliant!

The network offers Maker Faires all over the world, where you will find creative inventions that are often quite artistic as well. In the US, this movement has a “high-tech” element in it, using 3D printing and other energy and tech intensive methods. But many Makers especially in other countries, do a lot of inventing using whatever is lying around. Communities have arisen around this that one can access in many regions. See Further Resources for more info about this network.

Another use of cement, ferrocement tanks, by using bamboo slats for structural support, incorporates a “wattle and daub” approach (the wattle being woven wood or bamboo slats, the daub being earth, traditionally) to create large storage tanks for water affordably. 

Cement is used because it’s water resistant, but much less of it is needed, because of the “wattle,” than would normally be used to create a water tank. If there is limited access to cement or you want to use less of it because of the pollution from it, ferrocement is a good approach to use.

Some areas of the world still retain knowledge of how to make waterproof materials from lime, eggs, clay, sand, hair, etc. Natural builders are working to revitalize and preserve this knowledge. 

Lo-tech cooking and heating

Rocket stove or rocket mass heater is a simple, low tech design for a stove. They are tremendously efficient, thus allow the use of small twigs and sticks to cook on. This greatly reduces the need to cut down trees for firewood in countries that use wood or charcoal to cook with (millions of people). They can also be used when camping, or during hurricanes or just to keep the heat out of the kitchen in the summer (we would sometimes use them for this purpose), or to heat a home or water.

The stove can be built with many types of materials and with many designs as long as it has several elements:

     Chimney - this creates a draw of air which feeds the fire and creates a clean, efficient burn.
     Air flow chamber - this should be beneath the fuel so air is drawn through it.
     Fuel feed chamber - in this model, it is slanted so that fuel will self-feed as it burns.
     Cookware support - Something to set cookware on

 These stoves can include oven chambers, they can heat water by sending it around the chimney in pipes, they can be directed through benches or clay beds to heat them, or through walls or floors or masonry to heat a home with as little as one log per night. There is a copious amount of information on the internet about the various ways to build and use these. 

Biogas - It isn’t hard to capture the methane gas that comes from the breakdown of compost or manures. This gas can be used for cooking, heating or electricity. This is a huge topic. Biogas producers can be built with cement, plastic or metal containers. We use a manufactured biogas unit which works well and can produce up to 2 hours of cooking heat per day. https://www.homebiogas.com/ 

Solar ovens - Use the sun to cook! These devices have one thing in common which is that food cooked by the sun tends to taste great. The juices stay in, and flavors mix wonderfully. There are several basic approaches to using sun energy to cook food. 

 Box - the principle is an insulated box with a glass lid and metal reflectors surrounding it that send heat into the box. There are dozens of ways to do this, with varying degrees of heat gain, retention, and ease of use. 

Popular box solar oven, by SunOven.

Sun-baked cookies. We’ve made many solar cookers over the years using cardboard boxes, an old window or piece of plastic, and aluminum foil for insulation. [Note: aluminum is highly reactive and is essentially rated as toxic. The level of impact depends on each person, condition of kidneys, amount absorbed etc. If you are trying to keep anything toxic out specially avoid cooking using aluminum.]

Tube - these use glass, and reflectors both inside the tube and outside, to heat food. We like these because they are faster than boxes and compact. Being glass they can break! (Which happened to ours.)

Dish - these concentrate the sun energies into one spot which can get very hot. Depending on how they are built, they can get the hottest. There are many inexpensive varieties of these that don’t get very hot but are super portable. The hottest version can be dangerous; they can easily start fires or burn you. 

Heat from compost: When organic matter, such as food, manure, coffee grounds, leaves, etc, ends up in a pile, this creates an ideal environment for a bacteria that produces heat, called thermophilic bacteria. Those of you who do composting know this process well. This bacteria can send a compost pile to 120–140 F (49–60 C) or even higher, depending on the material used. 

But usually, this heat is ignored. It happens in the compost pile, the bacteria do their work, and die off. 

One man, however, started thinking about how he could capture this heat and use it himself. His name was Jean Pain. He cleared the underbrush from his wooded area every year, and composted it. He got the idea to wind a flexible pipe inside the compost as he built it up, that could capture the heat from the composting process and send it into his house. 

He also captured the methane gas given off by the decomposition process and used that for cooking heat, electricity, and to run vehicles. 

This can also be done on a smaller scale to provide heat for showers, etc. I’ve seen it done for hot showers using a pile about 5 ft tall, the heat lasted for many weeks. 

One can use fresh manure, food waste, coffee grounds, fresh grass or leaves, etc, all of which put out heat in the decomposing process. 

If you search Jean Pain compost method, you will find a number of Youtube videos and articles from others who have tried this method with success, and instructions on how to do it. If you have access to sufficient organic biomass (and there is literally tons of it thrown away every day in any city and most other areas), the cost to capture this heat is minimal compared to other options. It does take initial construction and good design but is dependable and creates self-sufficiency.

Refrigeration

17th century BC. Each circular home had many “modern” conveniences. There was a well, an oven and dome-like food storage in every house. The well branched out into two underground trenches: one of them was directed to the oven and the other one ended in the food storage.

The trenches were used to supply chilly air to the food storage. The cool air from the trenches was also creating a very powerful traction force in the oven, which made it possible to smelt bronze there.  Sintashta-Petrovka culture, associated with Indo-Iranians.

Zeer pots – inner pot has a lid, outer space is filled with sand and kept wet. The moisture evaporates from the side of the pot, cooling the inner chamber to as cool as 42F. This is used in some African markets to transport and store milk, meat, and other food that may spoil. It’s necessary to periodically refill the sand portion with water, so the evaporative cooling process continues. 

Note: Evaporative cooling works very well in drylands and poorly in humid climates. We have built zeer pots in Florida - during summer months when it is humid, they don’t work well or not at all. There is too much moisture in the air for the water to evaporate and thus, the system cannot cool. 

By 400 BC, Persian engineers had mastered the technique of storing ice in the middle of summer in the desert, in a Yakhchal. Aboveground, the structure consists of a large mud brick dome, sometimes 60 feet tall.

Below are deep underground storage spaces.  Windcatchers easily bring temperatures inside the space down to frigid levels in summer days. The massive insulation and the continuous cooling waters that spiral down its side keep the ice, stored there in winter, frozen throughout the summer. Part of why this works so well in the desert is because the water comes from mountain streams which are cold. Some of the water pipes run for many miles. 

Walls are made of a special mortar called sārooj, composed of sand, clay, egg whites, lime, goat hair, and ash in specific proportions, and which was resistant to heat transfer and waterproof. 

Some of these systems are still in Iran and operational. 

Again, this works better in drylands but is possible to design in such a way as it would work in humid areas as well. 

https://en.wikipedia.org/wiki/Yakhchal

Ice boxes, used in the US in past centuries, worked in similar ways on a lesser level. Ice from frozen lakes would be stored underground, surrounded by straw. The “ice man” would deliver ice to households once per week or so, and people would place it in a refrigerator-like “ice box”.

Staying cool

Low tech air conditioner. Cut holes in a styrofoam cooler. Place pipes and a small fan in appropriate holes. Place a bag of ice in the cooler. Turn on the fan and turn the pipes to face you. This works as well as central air and uses much less electricity (to cool the ice). One reason is because instead of cooling the entire room or house, you are only cooling a small area for a limited time.

Note that keeping ice packs in empty spaces in your freezer can actually make it work more efficiently during the hours they aren’t being used in this device. If you lose power during a hurricane, a few solar panels will keep your fridge going, and you can keep yourself cool with this device. This could be life saving in a heat wave if power goes off.

With it sucking in hot air the ice will of course melt faster than simply being stored in the cooler, leaving you with limited time but even when it is only cool water it could be better than nothing.

This is a termite mound in Africa. Their food needs to be kept constant at around 68 F in a desert where temperatures range from well over 100F to below 40F, sometimes in a single day. Its buttressed towers are built entirely from natural, biodegradable materials. Its inhabitants live and work in quarters that are air-conditioned and humidity-regulated, without consuming a single watt of electricity.

Termite mounds include flues which vent through the top and sides, and the mound itself is designed to catch the breeze. As the wind blows, hot air from the main chambers below ground is drawn out of the structure, helped by termites opening or blocking tunnels to control air flow.

Harare, Zimbabwe. The Eastgate mall and office building is modeled on the self-cooling mounds of African termites that maintain the temperature inside their nest to within one degree of 87F, day and night, - while the external temperature varies between 35F and 104F.

Eastgate uses only 10 percent of the energy of a conventional building its size, saved $3.5 million in air conditioning costs in the first five years, and has rents that are 20% lower than a newer building next door. This type of design, modeled after nature, is called “biomimicry.” https://inhabitat.com/building-modelled-on-termites-eastgate-centre-in-zimbabwe/