Low Energy Chest Fridge

“Using vertical doors in refrigeration devices is an act against the Nature of Cold Air. Understanding and cooperating with Nature rather than acting against it leads to much better efficiency. My chest fridge (Vestfrost freezer turned into a fridge) consumes about 0.1 kWh a day. This fridge is 10 to 20 times more energy efficient than typical household fridges on the market today.”

“It works only about 2 minutes per hour. At all other times it is perfectly quiet and consumes no power whatsoever. It is obvious that a truly energy efficient fridge does not cost any more money than a mediocre one. It actually costs less. It also has amazing food-preserving performance because temperature fluctuations in its interior are naturally minimized.”

Image: Dr. Tom J. Chalko.

“Comparing the daily energy consumption of various refrigeration devices available on the market reveals that well-designed chest freezers consume less electricity per day than refrigerators of comparable volume, even though freezers maintain much larger interior-exterior temperature difference (their interiors are much cooler). While chest freezers typically have better thermal insulation and larger evaporators than fridges, there is another important reason for their efficiency.”

“Vertical doors in refrigeration devices are inherently inefficient. As soon as we open a vertical fridge door – the cold air escapes, simply because it is heavier than the warmer air in the room. When we open a chest freezer – the cool air stays inside, just because it’s heavy. Any leak or wear in a vertical door seal (no seal is perfect) causes significant loss of refrigerator efficiency. In contrast, even if we leave the chest freezer door wide open, the heavy cool air will still remain inside.”

“The chest-style refrigerator is surprisingly practical and convenient to use. The most frequently used items are placed in top baskets and are very visible and very easily accessible. Baskets slide on top edges of fridge walls so that quick access to deeper sections of the fridge interior is possible without removing any basket.”

Read more and find the manual at Dr. Tom J. Chalko’s website. Thanks to Pablo M.

Making a Cooling Chamber for Tomatoes

When you pick your tomatoes, if you want to keep them longer, you have to find a way of reducing the temperature. As availability of electricity at village level can be a problem, ways have to be found to lower the temperature of this fragile crop. Some farmers at Dambatta in Kano State, Nigeria have used local mud bricks to make a very effective cooling chamber. Watch the video at AccessAgriculture. Via Practical Action.

Off-Grid, Solar-Powered, Zero-Battery Refrigerator

Joey Hess has designed, built and tested an off-grid, solar powered fridge, with no battery bank. Using an inexpensive chest freezer with a few modifications, the fridge retains cold overnight and through rainy periods. The set-up consists of a standard chest freezer, an added thermal mass, an inverter, and computer control. He writes: [Read more…]

Fermentation and Daily Life

There is a moment in the life of fruits and vegetables that has always puzzled and fascinated me. Put out a dish of strawberries, and in days some darker spots will appear. Maybe a thin tendril of mold sprouts out from the strawberry’s body. At this point, you can still eat it, simply by cutting off the moldy bit. But all of a sudden, the strawberry has clearly died. It’s inedible, sour. It has passed over in to the world of bacteria, mold, and minerals—it is no longer a self-regulating organism. It has stopped being an individual, but has become multitudes.

How does this happen? When is an organism living, and when is it dead? Where does death come from, and why does this change of state happen so quickly? Amazingly, we’ve developed some techniques to play with this boundary between life and death, stretch it, and blur it. I’m not talking about cryogenic freezing, blood transfusion, lab-grown meat, or any other modern technology. I’m talking about fermentation, the process of controlled decay of living organisms.

From coffee to ketchup, bread to sausage, wine to cheese, fermented foods are all around us. These types of fermentation tend to happen in far-off factories. Coffee berries are fermented before they’re roasted. To make ketchup, tomatoes are puréed en masse, left to rot, then heated to kill the bacteria. We usually don’t get the chance to see for ourselves the transformation of life—into other forms of life.

But you can. In this essay, I talk about fermentation: what makes it so magical, why people are so afraid of it. I talk about some strategies people use to make fermentation part of their daily life, and why modern life makes it so hard to do so. And finally, I speak to the ethics of fermentation—what we can learn from it and how it can help us think differently. [Read more…]

Historical Storage Cellars in Budapest

The Kőbánya district of Budapest is situated on the eastern margins of the Hungarian capital city. Beneath Kőbánya there is an extensive limestone layer, in which tunnels and passages have been made, some of which appear to date from the 13th century. In the 19th century, the limestone caverns of the Hungarian capital city Budapest were used for the refrigeration of perishable goods in large quantities.

This article analyses the architectural development of these evidently low-tech facilities, while also exploring their significant role in the city’s urbanisation. The technical functions and structure of the system of caverns may be useful as a resource for society in the future when the supply of fossil fuels runs out.

The effectiveness of the caverns as place for refrigeration can be demonstrated through climatic calculations. The cavern system has significant energy capabilities, given that there is a constant air temperature throughout the year.

Read more: Pilsitz, Martin, and Zsuzsanna Nádasi-Antal. “Historical storage cellars in Budapest: The architectural history and functional operation of an industrial building in 19th-century Hungary.” Építés-Építészettudomány (2018): 1-20.

Roman Refrigerators

Archaeologists are trying to definitively establish if mysterious shafts discovered at Switzerland’s extensive Augusta Raurica site in 2013 could have been ancient “refrigerators”. It is likely that the Romans used shafts like the four-metre deep examples at Augusta Raurica – some 20 kilometres from Basel – as cool stores during summer. [Read more…]