Frost Free Metsubushi

Jacob Perkins invented the compressor refrigerator in 1834. Einstein and his former student Szilard invented in 1926 a refrigerator with no moving parts. We used to have those in Romania in the 60s.

Japan feudal Police used the metsubushi (there is no plural in Japanese) supposedly to deter criminals.

But more modern refrigerators again use compressors. They are classified in current theories as heat pumps. One of the most overlooked devices that we all have in our houses. They taught us in engineering schools and faculties for HS physics teachers all kinda useless things. But never they spoke in detail about heat pumps. The reason is they are over unity devices. Because they do not simply transform electrical energy from grid into heat. They move heat from inside the fridge to outside. The idea is very simple. According to known laws of physics, all energy used by the fridge from grid is transformed in heat inside the compressor. That is all your consumption from the grid. The outer coil of the fridge eliminates that heat in the environment, that is your kitchen. However. More heat is being evacuated than the heat produced by the mechanical work of the compressor and that is the heat transferred from inside the fridge also to outer coil.

It was three years after the invention of the Einstein Szilard refrigerator that Szilard publicized one of the most shocking and influencing ever scientific article. Entropy can be reversed. They didn't teach that in colleges either. That paper started the great depression of 29 end everything after. 91 years of struggle, wars and mystery.

But these were not the reasons i started to write this. I said all those things before. There is a reason much more practical. The major health problems the current design refrigerators cause.

In the beginning of modern era compressor fridge there was the frost problem. Water from air mainly resulted from opening the fridge but also from food drying inside would condensate and freeze on the inner coils. Ice is an insulator, and that resulted in loosing efficiency of the fridge. Periodic unfreezing was necessary. That was done by emptying and cleaning the fridge and let the ice melt. Some fridges had a pipe from where the water was flowing, i don't know where. Maybe in a pan under the fridge.

Don't know and it's not so important who invented the frost free fridge. But it's not so orthodox most of us think.

Ice first stat building on the inner coil behind the back wall of the freezer section in this picture. If you can remove ice there, you will have no ice in the rest of the freezing compartment, like in the picture above.

They added a timer to the fridge and a resistor to the inner coil (behind the back wall in this picture) and approximately every 8 hours the fridge stops refrigerating and the resistor heats up the coil for about half hour until the ice is melted. For that half hour, temperature raises inside the fridge obviously but i never heard anybody complaining about their food being exposed to higher temperatures during that time. Maybe because they don't know. Water resulted from de-freezing will fall through a pipe into a pan under the fridge and because the pan is exposed to the heat of the outer coils (usually behind the fridge for that type) and the heat of compressor it will evaporate. That water is not clean cause it caries old food crumbles but worse, in a few years some sort of mud will start building up, because that water attracts dust from your environment. Few know about that as well.

But the worst. Lately they moved the outer coils under the fridge (where they can't be seen and cleaned) and added a fan for cooling the outer coil for efficiency. The coils are significantly smaller. You will not hear that fan because it always works in the same time with the compressor. Pan is not heated but water is evaporated from it by that fan as well. Not much mud is built in the pan either. Cause when the water dries, the dust is blown by the fan as well. Well, most of it.

Last night when the fridge started, Angela sneezed. This morning i woke up after 5 hours of sleep with pain all over my body, like i had all week. I had too major dust problems this week at the apartment. Monday some litter dust was releases from one of the apartments above nearby. Wednesday they blew the parking lot and the redwood mulch area around the building. I lost the opportunity to take a picture. They raised dust all the way to heavens, reducing visibility. Then it fell on the stairs, walls and screens. Constant flow of air from under door brought it inside. Both types of dust have their own characteristics and are very irritant, painful on skin, changing your mood, habits and generally all your life. Some of the dust ended under the fridge, the fridge's coil, wires and cardboard lid that covers the case behind the fridge.

That piece of cardboard, believe it or not, also have the role of attenuating the ultrasound created by the hissing valves (those which allow the Freon to compress and expand). High intensity ultrasound can also be in time a health problem cause it penetrates tissues.

The cardboard is perforated in the fan's area so the hot hair from cooling the coil can escape in the environment.

This morning i pulled the fridge from the wall, removed the cardboard cover, tilted it and cleaned it, first time after two months. I used a 2 gallon garden sprayer with a manual pump, hot water and one drop of laundry detergent. Cardboard had dust buns inside (invisible from outside) in the area of the perforations, when the fan blows. I din't look at the coils under. I know they had dust on. Dust that gets heated when the compressor starts.

People don't pay attention to these things. They don't create much problems on the short term. Some take on the problem of efficiency because dust buildup reducing the cooling capacity of the outer coil, which is not the biggest problem here (picture below).

Nothing more than a sneeze and unpleasant smell when they start. Soon after, the smell clears and/or people get used to smell and dust. But there are enough pictures on the web to figure the dimension of the health problem created by it.
I have a degree in mechanical engineering, also worked as technician (both in partially artificial environments but still) and all i can tell is they have to change the design of the fridge to eliminate these problems. Only real solution i can see is hooking the fridge to water supply and drain and use small amounts of water for cooling the outer coil and eliminate pan, fan and drain the water from de-freezing. But this won't happen unless the people complain and people don't complain because they don't know and love the convenience of a fridge you don't have to hook up to nothing.