Alternative refrigerators

The first residential absorption refrigerator was shown at the Universal Exhibition in Paris in 1887. It was a bulky cabinet with a fridge compartment that was tiny by today’s standards. Food was kept fresh in it for up to two or three days in hot weather! It seemed like a miracle at the time, although the temperature in the refrigerator has not yet learned how to maintain a constant.

Between the past and the future

As the years passed and circumstances changed, the sensational cabinet became one of our essentials.

But for many decades after that, the household refrigerator merely learned to hold more in its womb. It was a landmark when Candy developers fitted the inside panel of a refrigerator door with handy shelves for the first time. After several decades, we have added an automatic evaporator defrost and an optional frost-free evaporator mode.

Dramatic changes in home refrigeration are taking place so quickly that we can barely keep track of and analyse them.

And the time is not far off when there’s probably no point in buying or storing food before it’s ready. And fridges could disappear from our everyday lives altogether. Because in every “smart house” of the not-too-distant future there will be nanotechnology in its “smart kitchen” to grow any protein and other fresh nutrients right to the dinner table.

All the more so when the science of nanotechnology, which has been developing since the 1970s, is now joined by cloning technology. Our taste preferences, nutritional content, vitamins and minerals can all be effortlessly programmed into the biogenerator. What this biogenerator will look like? Won’t you get nostalgic for a good, fat and cozy rumbling fridge??

He’s still with us today. Today it is still the number one necessity in every kitchen. And it’s nice.

Magnetic force freezes everything

The first magnetic refrigerator in the world is built at the Department of Energy’s Ames Laboratory in the US. Its principle of action is based on the ability of some alloys to heat up when the magnetic field strength increases and cool down when it decreases.

Although this phenomenon was discovered more than eighty years ago, it has only now found practical application. Engineers are convinced that refrigerators and air conditioning systems based on this technology can go on sale in the next few years. There are already working prototypes of a new type of magnetic refrigeration unit.

It may not be long before foods everywhere are cooled by a rotating metal disk, a permanent magnet, and a small amount of water. How will this work??

A flat metal disk is rotated between the poles of a permanent magnet so that only part of the disk is magnetized, with the rest remaining outside the field. When this part is pushed into the magnetic field area, tiny bipolar magnets in the disk material line up along the lines of force, and the temperature of the disk at that location rises. The heat generated is dissipated by the water circulating in the area.

And when this part of the disk moves out of the magnetic field, the magnets in it are no longer held by its lines of force and again turn randomly, expending thermal energy to do so and thereby cooling the disk below the ambient temperature. And it cools the water that washes it in the second circuit. This chilled water is used as a refrigerating agent in the new magnetic refrigerator.

In order to increase the efficiency of magnetic cooling, researchers are searching for the best material for the disk. The one in operation now uses a gadolinium disc, a rare-earth metal which goes on the recording heads of VCRs. Cheaper materials are also available.

Magnetic refrigerators are in any case cheaper to operate, they are environmentally friendly their refrigerant is ordinary water and practically noiseless. Time will tell if they will be parallelepiped, cylinder or ball-shaped. It won’t be long now.

The cold comes from the sun?!

Besides the classical compression method of cooling, the thermoelectric cooling effect has been used in the world in parallel for a long time. As early as the 19th century it was discovered that the junction of conductors of different materials is cooled or heated when a direct electric current flows, depending on the direction of the current “Peltier effect” . But this effect was weak and of only scientific interest.

Only with the beginning of the widespread use of semiconductor materials was it possible to adapt this physical effect to practical application.

Thermoelectric refrigerators have been around for decades, but even today there are many people who have never heard of them. Because such refrigerators are used in a narrow field. The matter is that it is not yet possible to reach the same usable volume of the refrigerating chamber, as compression refrigerators have.

Therefore, mainly the thermoelectric refrigerators exist in the form of devices of a modest size, powered from the car battery. Occasionally they can run on solar panels. Here’s a funny paradox: the sun generates cold!

Portable thermoelectric refrigerators are also not very big, but they can be connected both to a battery 12 V and to 220 V. In common use they are called coolers from cool in English . Most coolers are made in the form of insulated chest chest with hinged lid. They have handles or wheels for transportation.

However, the small volume of coolers can be advantageously presented as a compact. The thermoelectric principle makes it possible to create refrigerators that can easily fit even in your pocket for example, for cooling medications . Our defense industry offers compact coolers to cool, for example, one can of beer. They are fixed near the dashboard of the driver in the car.

Coolers are reliable and noiseless thanks to the absence of moving parts, have almost an eternal service life, and are environmentally friendly they do not require refrigerant gas . They can be placed sideways, upside down – as you prefer, they will work flawlessly, withstanding a ride on a rough terrain. No other compression refrigerator could withstand such rough treatment.

The disadvantages are low efficiency only 16-17% and instability of temperature inside the cooler, it directly depends on the ambient temperature. In hot weather cooling leaves a lot to be desired.

But there is a “zest” in thermoelectric design. As already mentioned, the thermoelectric effect can cause not only cooling, but also heating. It depends on the direction of the current. After changing the contacts with the help of a switch the refrigerator becomes a heater for chilled food or, for example, baby food bottles . Very convenient on the road or on a picnic.

Transparent doors don’t let heat in

There are now new refrigerator models with a glass door. Seemingly nothing new, refrigerators with glass doors have long been used in the trade. But the thing is that it is not just a glass door, but a triple vacuum glass pane. Similar to what they put in today’s hermetically sealed windows.

Turns out to provide noticeably better insulation than traditional porous insulating materials. This makes the fridge use less energy than a 60 W light bulb!

Economic efficiency also increases at the expense of the transparency of the door. If usually when you open the fridge it takes some time to distractedly look for what you need, with the glass door you can “see” the right package in advance and then open the fridge. The time the door stays open is several times shorter.

On the American market refrigerators with glass door-glass panels are already presented by the German company Gaggenau.

More goes in, less is spent

At the beginning of the development of domestic refrigerators the cylindrical shape of the body was seriously discussed. Many people were only amused by this, but in fact the idea is full of deep practical meaning.

To begin with the fact that the more energy efficient a fridge is, the smaller the ratio of its surface to effective volume. That is the smaller is the surface at the same volume, the less generated cold is lost because of radiation from the surface and the less energy is required for its operation, all other conditions being equal.

For example, if to take the volume of a cube as a unit and take the surface of this cube as 100%, then a parallelepiped of the same volume but with the ratio of sides 0.7h0.7h2.1 very widespread proportions of a fridge will have the conditional surface 114. And that means that such a parallelepiped will lose 14 percent more cold than a cube.

And a cylinder with the ratio of diameter to height 0,9 to 1,58 also very popular proportion for a fridge has conditional surface of 96% and will lose cold by 4% less than a cube and 18% less than a parallelepiped. It would seem, not so much, but at round-the-clock and year-round work there is rather essential economy.

In addition, refrigerators in the form of a cube, cylinder or sphere and why not?? will be lighter and their production will require less material than that of parallelepiped refrigerators of the same effective volume.

And the ball will have the smallest possible surface area equal to 81% of a cube’s surface…

Why Eskimos build ice houses half-sphere?

This mathematical conclusion is clearly evident in nature and in the shape of many of the natural formations around us, from the planets, stars and our sun to apples, watermelons and other spherical fruits. Eskimos intuitively build their ice houses-icles hemispherical, so they lose as little heat as possible from the hearth burning inside…

So the most rational from the point of view of thermophysics design of a refrigerator is spherical! But nobody has so far been able to think of the best way to use the internal spherical volume of such a refrigerator and where such a refrigerator would have a door…

The next very economical design is a cylinder, elliptical or circular in cross section. You will agree that it is quite acceptable for domestic conditions, but for a long time the appearance of the cylindrical refrigerator was restrained by the conservative design of our kitchens, where everything is subject to straight lines. Therefore the models of the form of a rectangular parallelepiped equal in two directions from the energy point of view were replicated and continue to be replicated.

The “Lazy Susan” went to the masses

It has not taken more than a hundred years of thinking over the problem when cylindrical refrigerators appeared on the market! Today, for example, they are made by the American corporation Equator.

At 68 inches 170 cm high and 30 inches 75 cm in diameter with the door open, its size is 39 inches, or 97.5 cm. This model has a usable refrigerator compartment capacity of 242.3 liters and freezer compartment capacity of 83.1 liters. Not bad! A refrigerator of the traditional rectangular shape with such a capacity has the dimensions of 186x60x60 cm.

Cylindrical refrigerators are not only more economical in terms of energy consumption, but also lighter and cheaper they use less material . Manufacturing a cylindrical body is more technologically advanced and cheaper than a rectangular one.

The freezer compartment in this model is bottom-mounted and has a separate compressor. Fast freezing mode produces ice cubes in less than an hour.

The cylindrical refrigerator has rotating sliding glass shelves of the “Lazy Susan” type. A name every American saloon-goer knows. There’s a name for the rotating device that replaces the sluggish food plate dispenser.

Rotating shelves of the cylindrical refrigerator facilitate the access to the required products and the tempered glass of which they are made ensures the convenient overview of all the contents of the refrigerator.

The concept of a bio-freezer

The unusual freezer works completely differently from conventional models – it’s four times smaller than conventional models, and it’s cooled with biopolymer gel. Instead of the usual placement on the shelves, a non-sticky, odorless gel envelops the food, as if putting it in a capsule.

It’s four times smaller than a conventional refrigerator and cools with biopolymer gel. Instead of shelving, the odorless, non-sticky gel envelops the food as if encapsulating it.

Absence of doors, shelves and motor enables using 90% of the whole usable volume of the fridge for food storage. Preserves the natural flavor and aroma of the food. Foods do not dry out because there is no convection.

The working principle of the bio-freezer: conversion of invisible infrared radiation into visible light. It cools by absorbing heat energy and emits it in a different wavelength range. The same principle is applied to the paneling on the Space Shuttle.

The cooling process requires no energy. The food is immersed in the gel. Strong surface tension creates a separate capsule for each product. The shape of the fridge can vary depending on its content. The more food it holds, the more space it takes up. Usable volume can be increased up to 300%.

The refrigerator can be installed either horizontally or vertically, and even on the ceiling. Adjustable dimensions allow it to adapt to any dwelling. You don’t need to provide space for opening the door, the chamber doesn’t need to be cleaned and, most importantly, it consumes less electricity. The bio-freezer takes up a fraction of the space of its predecessor. Even the name “fridge” doesn’t fit anymore it’s more like a refrigerated bath.

The cooling process is accompanied by a gel glow – luminescence. The operation of the appliance becomes a fascinating spectacle.

Summary:

– The process of operation does not require any energy to cool the food

– Design feature – 4 times smaller than a conventional refrigerator, it changes shape depending on the load

– Absence of shelves and doors allows to place it both vertically and horizontally

– Gel is not sticky, odorless

– High storage density, volume is used as efficiently as possible

– Food is always in view and easily accessible

– Completely silent operation, no moving parts.