Continued from "
Solar Pantry Part 2: Analysis."
Trying to solve my potential problem of losing refrigerated and frozen food during a prolonged power outage sent me scouring books and websites for
affordable ideas. People preserved their food for millennia before they had electricity and refrigerators, but like other traditional knowledge and skills, the how-to has been forgotten, lost, or simply discarded in favor of high-tech alternatives. Unfortunately, not all of the technology we laud has been terribly smart: the processing and overuse of fossil fuels for example. The simpler the better, I say.
So while Dan and I are discussing options and forming a plan, I've been collecting ideas. This is what I've got so far, pretty much organized from lower tech to higher. Obviously, not all of them are feasable for everyone, because they depend on regional resources and conditions.
Spring house - If one is lucky enough to have a wellspring on their property, this would be an excellent option. A spring house is a small structure built over the spring to take advantage of its cold water. The water flows through shallow troughs into which food containers (usually milk cans) are placed.
I had friends who used an old chest freezer in a similar way. Spring water flowed through it via inlet and outlet pipes. The chilly spring water kept their milk quite cool.
Ice house - For those living with long hard freezes, this is an idea. Ice is harvested in large blocks from solidly frozen lakes.
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Photo: Library of Congress (https://www.loc.gov/resource/det.4a05655/)
There's an interesting ice harvesting photo story at A Continuous Lean. |
Then it's packed in saw dust or straw in an ice house.
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Indiana ice house. Photo from Library of Congress
https://www.loc.gov/pictures/item/in0268.photos.065885p/ |
The saw dust or straw acts as insulation and slows melting. Some farmers made their own forms to make their own ice blocks.
Cool chamber - A variation of the simple ice house.
The ice house is built into a hillside with a room underneath for storing milk, fruits, and vegetables.
Chamber Refrigerator - Similar to the cool chamber.
The chamber is built so that top, back, and both sides are surrounded by ice. The space under the ice is for ventilation.
Ice Box - No electricity required for those with a source for ice!
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Israeli, I believe. Attribution: יעקב [CC BY-SA 4.0
(https://creativecommons.org/licenses/by-sa/4.0)] |
The top compartment holds a large block of ice which cools the contents in the compartment below. Note the drip pan to catch melting water underneath. Ice tongs hang on the side.
Well shaft - For those who have an old-fashioned well!
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| LOC, https://www.loc.gov/pictures/item/2017782495/ |
A food box or bucket is lowered and tied off just above water level, where the contents stay cool.
Silos (trenches) - These aren't the grain silos we're familiar with. The French term means "underground excavation used to preserve foods."
This example measures 16" x 32" and is 20" deep. A lining of brick keeps rodents out. Vegetables are packed in layers of dried leaves. The wood cover is heavy and air tight. A well-drained location is important.
Root cellar - A more familiar form of food storage. It is basically a handmade cave built into a hillside or of mounded earth. In modern lingo we could call it geothermal cooling.
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Root cellar in Itasca County, Minnesota. Photo: LOC
https://www.loc.gov/pictures/item/mn0482.photos.342773p/ |
Root cellars tend to get damp and musty, however, so good ventilation is very important.
Windcatcher - This isn't for food storage, but rather a middle eastern house cooling system.that seems to lend itself to food preservation, providing one has wind and a qanat (underground water transportation channel). The basement would the perfect place for a root cellar.
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Click to enlarge. Attribution: Wind-Tower-and-Qanat-Cooling-1.jpg:
Williamborgderivative work: Monsih [Public domain] |
It's an example of evaporative cooling. The principle is that water absorbs heat in order to evaporate, cooling dry air significantly and with much less energy than refrigeration. It's best suited to dry climates, because it apparently gets very musty in humid climates, where it's earned the name "swamp cooler" because of the odor it produces.
Zeer Pot - Another ancient middle eastern technology that takes advantage of evaporative cooling. Also known as a pot-in-pot "refrigerator." A small clay pot is placed into a larger clay pot and the space between is filled with sand. The sand is kept damp and evaporation keeps the contents of the smaller pot cooler than the ambient temperature.
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| My experimental zeer pot. |
I tried this method when I was researching off-grid eggs, cheese, and meat storage for
Prepper's Livestock Handbook. Unfortunately, my experiment was a fail because of our humidity. The higher the humidity the slower the evaporation. There's a techy explanation of all that over at the
Rebuilding Civilization blog. If you have a dry climate this won't actually refrigerate, but it will act as a cooler to increase longevity of some foods.
Cold shaft (a.k.a. cool cupboard or California cupboard). Heat rises and this is what the cool cupboard takes advantage of. The shaft is open at top and bottom to allow a cooling air flow. Wire shelves inside the shaft hold food items.
Screens at top and bottom keep rodents out. These work best if they are built on interior rather than exterior walls. You can see a modern one in use at the
Lewisham House and Farm blog.
DC (Direct Current) Refrigerators and Freezers
These 12- or 24-volt appliances can be powered by solar, wind, fuel cells (hydrogen), or batteries; sources that deliver DC (direct current) electricity, as opposed to the alternating current (AC) we receive from the grid. They're pricey, however, ranging from $700 for a dorm-size 1.8-cubic-foot fridge or freezer, to $1600 for a 13-cubic-foot freezer or a 15-cubic-foot fridge. Solar panels or wind turbine and batteries not included.
Thermal mass refrigerator - From
Earthship Volume 3 by Michael Reynolds.
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Attribution: KVDP [CC BY-SA 4.0
(https://creativecommons.org/licenses/by-sa/4.0)] |
It's designed around a DC refrigerator (above) run on solar panels. For the diagram key see the summary at
Wikimedia Commons.
Solar ice maker - About ten years ago four engineering students at San Jose State University made a solar ice maker for about $100.
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| Solar ice maker. Photo © San Jose State University |
It was an example of absorption chilling, not a new technology, but their project seemed to create a renewed interest in the process. Absorptive chillers use heat (like the sun) instead of a compressor. A refrigerant (like ammonia) is heated, cooled, and circulated to produce temperatures cold enough to make ice. Combine a solar ice maker with an ice box, and that would be a wonderful non-electric way to have refrigeration. I'm still looking for DIY plans. [UPDATE: How-to at
Knowledgeable Ideas, although it's too big for an ordinary small family.]
The absorption refrigeration cycle was discovered in the mid-1800s by Ferdinand Carre. He invented and marketed the IcyBall around 1858 as a cooling device in homes.
The device was sold during the 1920s and 30s, but apparently was discontinued when a number of them exploded. I suspect this was because it required the owner apply heat to activate it. Getting distracted for even a few moments could chance disaster! There's an interesting webpage on it's history
here.
Solar Refrigerator - Was invented in the mid-1930s by Otto H. Mohr. It also uses absorption cooling technology, and was said to only need two hours of sunlight per day.
Mr. Mohr received a
patent for his design in 1940, but it doesn't seem to have ever made it into production.
Wood burning refrigerator - Another example of absorption chilling.
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Click to enlarge. Image from Mother
Earth News. Click here for full article. |
Developed by Dale Degler (in the 1970s I think), he calls it an intermittent absorption refrigerator. It only needs a 20-minute fire every 24 hours! I'm not sure he ever actually made one, however.
There are other ideas out there, like propane and LP refrigerators and freezers, but I stuck with ideas that use renewable energy sources. I don't mind buying the materials to make and set up the system, but the idea is to not rely on buying the energy or fuel to run them.
Obviously not all of these ideas are applicable to Dan and me, but they do show how it's possible to preserve food without electricity. And they have kept me from being too discouraged after
my solar pantry feasibility study.
Next →
Solar Pantry Part 4: The Plan
