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.

How to Build a Persian Windmill

“This paper investigated a windmill in Nehbandan which is an example of architectural heritage. Harnessing natural energy and using local materials such as stone, wood and adobe, the residents were able to create environmentally friendly structures. In this paper, one of these windmills that is still standing in Nehbandan was selected from a chain of windmills. Then, based on architectural survey, interviewing with millers and sketching, the dimensions of architectural elements and mechanical components were obtained and the windmill was modelled.”

“The results reveal that there is a close relation between architectural features and mechanical components. The orientation of this windmill toward prevailing wind, the correct placement of walls in three faces and creating a hole named Darvazeh in the third wall to direct the wind into the Parkhaneh are architectural features which provide the kinetic energy of the wind to move the mechanical components. The stepped form of the surrounding walls prevents erosion of mechanical components and as a result increases the durability of the windmill.”

Zarrabi, M., Valibeig, N. 3D modelling of an Asbad (Persian windmill): a link between vernacular architecture and mechanical system with a focus on Nehbandan windmill. Herit Sci 9, 108 (2021). https://doi.org/10.1186/s40494-021-00587-0

https://heritagesciencejournal.springeropen.com/articles/10.1186/s40494-021-00587-0

DIY Wooden Bike Trolley

Marie Verdeil made a tutorial for a simple wooden bike trolley. It is available in English and French on the Low Tech Lab wiki.

Method to create a simple bike trolley, using up-cycled materials. Easily fixated to every bike (adult size). Holes on the board help attach any kind of cargo. It’s made out of wood and simple hand tools, no welding required. Dimensions are detailed and can easily be adapted to the material available.

I tried to create a trolley, which can replace the car to go to the market / grocery shopping. No need to transport heavy cargo, but big objects (cardboard boxes, crates, wood, etc.) – Therefore it needs to be easily adaptable, with the option to fix a crate on the board. + Priority goes to second-hand materials!

Solar Concentration for Craft Practice

“This research indicates the technical capabilities of using a 40 cm2 Fresnel lens to heat, melt and vitrify a variety of materials and suggests future applications of this technology including the ability to digitise the process. This material processing technique offers an alternative to heat matter and is significant in geographical locations with ample sunlight, offering a cost-effective option to traditional heating methods and allows directional heating, which local craftspeople can exploit to their creative advantage.” [Read more…]

Low-tech Zine

Brazilian “mini-publisher” Casatrês made a beautiful zine which includes three articles from Low-tech Magazine, translated into Portuguese. It is for sale on their website.

Damaged Earth Catalog

“We are humans and might as well get used to it. So far, remotely done power and glory—as via government, big business, formal education, church—has succeeded to the point where gross profits obscure actual loss. In response to this dilemma and to these losses a realm of intimate, community power is developing—power of communities to conduct their own education, find their own inspiration, shape their own environment, and share their knowledge with others. Practices that aid this process are sought and promoted by the DAMAGED EARTH CATALOG.”

–> Damaged Earth Catalog. [Read more…]