Today it is difficult to imagine a kitchen without an electric cabinet that cools food at the touch of a button. However, the path to this comfort was long and full of experiments with dangerous gases, ice and complex mechanical systems. Initially, people used glaciers - cellars where snow and ice were transported in winter, but this was a temporary solution depending on the season.
The real revolution began in the 19th century, when engineers learned to artificially obtain cold. The first refrigerators they worked not from electricity, but from kerosene, gas or even wood. The principle of their operation was radically different from the compressor units we are used to, based on the absorption or evaporation of volatile liquids.
To understand exactly how these bulky and noisy predecessors of modern systems functioned, it is necessary to dive into the history of engineering of that time. Refrigeration technologies have gone from simple evaporation of ether to complex cycles of ammonia compression. Let's figure out what physical laws underlay these devices and why they were considered a miracle of technology.
The principle of operation of absorption systems
The most common type of early refrigerators was the absorption machine. Unlike modern models, where the refrigerant is compressed by a mechanical compressor, here the circulation process was ensured by heat pump. The main working substance was most often ammonia, and the absorber was water.
The process began with heating the generator, where a mixture of ammonia and water was supplied. Under the influence of temperature (from a kerosene burner or gas wick), ammonia evaporated and entered the condenser under pressure. There it cooled and turned into a liquid state, after which it entered the evaporator, where, expanding sharply, it took heat from the fridge compartment.
The key difference was the absence of moving mechanical parts in the circulation circuit. Absorption cycle it was ensured only by the difference in temperatures and densities of substances. This made such devices relatively quiet, although extremely fuel-hungry.
- 🔥 Heating a mixture of ammonia and water in the generator starts the process of separation of substances.
- 💧 Water absorbs ammonia vapor in the absorber, creating vacuum for evaporation.
- ❄️ Evaporation of liquid ammonia in the storage chamber provides direct cooling.
⚠️ Warning: Early absorption systems operated at high pressure and used toxic ammonia. A leak in a residential kitchen could be deadly, so such units were often installed in separate extensions or basements.
Evolution of compressor refrigerators
In parallel with absorption models, compressor systems also developed, which eventually became the industry standard. The first household refrigerator s The electric compressor appeared at the beginning of the 20th century. Its operation was reminiscent of the principle of operation of a steam engine, but in the opposite direction.
The electric motor drove a piston that compressed the gaseous refrigerant. When compressed, the gas heated up and gave off heat through a radiator on the rear wall. Then, passing through the throttle (expansion valve), the gas was sharply cooled and entered the evaporator inside the chamber. One of the main problems of the early models was the reliability of the motor. Electricity was unstable and the engines often overheated. In addition, sulfur dioxide and methyl chloride were used as refrigerants, which were corrosive and required perfectly sealed systems.
One of the main problems of early models was reliability seals and motor. Electricity was unstable and the engines often overheated. In addition, sulfur dioxide and methyl chloride were used as refrigerants, which were corrosive and required perfectly sealed systems.
Engineers of that time were looking for ways to make the cycle more efficient. They experimented with the shape of evaporators, introducing tubular heat exchangers instead of flat containers. This made it possible to quickly remove heat from the products, but required more powerful compressors.
The design and key components of early models
The design of the first refrigerator was much more complex than the modern one. If now all the components are hidden in a compact block at the bottom or behind, then before each element was visible and required maintenance. The basis was a generator, a condenser, an evaporator and an absorber (in gas models).
Materials also played a critical role. The housings were often made of wood with zinc or copper internal lining. Thermal insulation made of cork, sawdust or slag wool, which was less efficient than modern polyurethane foam, so the walls were made very thick.
The most important element was the regulator temperature. In the first models it was absent as a class, and the user had to manually adjust the supply of fuel or air to the burner. Later, bimetallic thermostats appeared that mechanically shut off the gas supply when the desired cold was reached.
| Component | Function | Material (XIX-XX century) |
|---|---|---|
| Generator | Separation of the mixture of refrigerant and absorber | Cast iron, steel |
| Condenser | Gas cooling and liquefaction | Copper tubes with fins |
| Evaporator | Direct chamber cooling | Tinned iron, copper |
| Absorber | Refrigerant vapor absorption | Steel containers |
It is worth noting that the maintenance of such systems required qualifications. Refrigerator repair in those days it was the lot of engineers, not household craftsmen, as it required soldering pipes under pressure and working with chemically active substances.
Safety problems and refrigerants
The history of refrigeration is full of tragic pages associated with the toxicity of the substances used. Before the invention of freon in the 1930s, engineers were limited in their choice of working fluids. Ammonia, sulfur dioxide, methyl chloride - they all posed a threat if leaked.
Methyl chloride, which was used in many of the company's compressor units, was considered especially dangerous. Frigidaire. It had no odor, but when concentrated in the air it caused poisoning, and in combination with an open flame it could form phosgene, a chemical warfare agent.
It was safety problems that prompted chemists to search for inert gases. Thomas Midgley Jr. and his team developed Freon-12that was non-flammable and non-toxic. This was a turning point, allowing refrigerators to be moved from basements directly into the kitchen.
⚠️ Attention: If you are restoring an antique refrigerator (pre-Freon era), do not under any circumstances try to run its original system. Residues of ammonia or sulfur dioxide can cause a chemical burn to the respiratory tract during disassembly.
Household glaciers and the transition period
Before mechanical refrigerators became widespread, so-called “iceboxes” were popular. These were wooden cabinets with an interior made of zinc or enamel, with a huge piece of natural ice placed on top.
Cold air, being heavier than warm air, fell down, cooling the food. Melt water collected in a tray, which had to be emptied regularly. It was a kind of transitional stage between ancient cellars and electric miracle machines.
- 🧊 Ice was purchased from "ice makers" and delivered by special carts.
- 💧 Condensation required constant monitoring, otherwise the cabinet would turn into a swimming pool.
- 🌡️ The temperature inside rarely dropped below +5...+7°C, which was not enough for long-term storage of meat.
With the advent of electricity, glaciers began to be equipped with electric coolers, but the principle remained the same. It was only by the 1940s that mechanical systems completely replaced ice from everyday use in developed countries.
Why were the first refrigerators so big?
The dimensions of the first refrigerators were explained not only by the desire to accommodate more food. Thick walls insulated with cork and sawdust took up a lot of space. In addition, complex pipe systems, generators and absorption tanks required significant space to be placed inside the housing. Modern materials make it possible to make walls a couple of centimeters thick while maintaining the same level of cold.
Energy efficiency and economic aspects
The efficiency of the first refrigerators left much to be desired. Absorption models consumed huge amounts of fuel. The kerosene lamp had to burn around the clock, which made operation expensive.
Electric compressor models were also not nearly as efficient. Efficiency Early engines were low, and the on/off cycles were not precisely regulated. This led to excessive consumption of electricity and overheating of the motor.
However, for the middle class of that time, having a refrigerator was a matter of status and hygiene. The ability to store food for several days without the risk of poisoning outweighed the cost of ownership. Technology gradually improved, more efficient compressors were introduced and thermal insulation was improved.
Modern devices operating on the same principle, but using inverter technologies and environmentally friendly gases (isobutane, propane), consume tens of times less energy. However, the basic physics of the process - the extraction of heat during the evaporation of a liquid - has remained unchanged since the 19th century.
Frequently asked questions (FAQ)
When did the very first refrigerator appear in the world?
The first working prototype of artificial refrigeration was created by Jacob Perkins in 1834. However, the first household refrigerator available for purchase appeared in 1913 (the Domelre model), and mass production began by General Electric in 1927 with the Monitor-Top model.
What did the first refrigerators use?
The absorption models used a mixture of ammonia, hydrogen and water. In compressor rooms - sulfur dioxide, methyl chloride or sulfur dioxide. These substances were effective, but extremely dangerous if leaked.
Why did the first refrigerators run on kerosene?
At the beginning of the 20th century, electrification had not yet reached all homes, especially in rural areas. Kerosene was an accessible and cheap fuel, which made it possible to use absorption refrigerators where there was no electricity.
How long did the first refrigerator last?
The service life of early models was relatively short, about 5-7 years, due to corrosion of pipes, wear of seals and instability of electrical networks. However, some industrial designs worked for decades with proper care.