The question of which one chemical equipment required for the evaporation process in the context of refrigeration technology, often baffles non-specialists. It is important to immediately clarify: in household compressor refrigerators of the classic type, the evaporation process occurs within a closed loop, and the user does not need to purchase external chemical reagents or laboratory glassware for their maintenance.
However, if we are talking about absorption refrigerators (often used in camping or industrial installations) or procedure for professional refrigerant recovery, the list of necessary equipment changes radically. In such systems evaporation is a key stage of the cycle where the liquid refrigerant must go into a gaseous state, absorbing heat from the chamber.
Let us consider in detail which components and devices fall into the category of equipment for evaporation, and why confusion in terms can lead to errors when repairing or upgrading equipment. Understanding the physics of the process will allow you to distinguish standard components from auxiliary tools.
The fundamental difference between evaporation and evaporation in the refrigeration cycle
In the thermodynamics of refrigeration machines, the term “evaporation” is often used as a synonym for the phase transition of liquid into vapor, but in an engineering context these are different processes. In a standard cycle of a compressor refrigerator, the refrigerant boils at low pressure in a heat exchanger, which we call evaporator. This is a standard unit built into the design.
The situation changes when we talk about rectification or cleaning the refrigerant. Here, evaporation is understood as the forced removal of volatile fractions or moisture from oil and freon. This requires external equipment, which is not included in the basic package of a household appliance, but is necessary for service engineers.
⚠️ Attention: An attempt to independently extract the refrigerant for “evaporation” without specialized equipment (recuperators) is prohibited by the legislation of many countries due to environmental risks and the danger of depressurization of the system.
The key element here is understanding pressure. In order for a substance to boil at a low temperature (for example, -20°C), it is necessary to create rarefaction conditions. Without a vacuum pump and a pressure manifold, it is impossible to control this process.
Main components of the evaporation system in absorption refrigerators
If your request concerns specifically absorption systems (working on an ammonia-hydrogen mixture or lithium bromide), then the “chemical equipment” here are the internal components of the unit itself. In such models, the role of a mechanical compressor is played by a heating element and a diffusion system.
The central element is desorber (or generator), where under the influence of heat ammonia is evaporated from an aqueous solution. This is a complex heat exchanger, often combined with a rectifier to clean steam from water impurities. Without a working desorber, the cooling cycle is impossible.
Also critically important dephlegmator is a device where some of the vapor is condensed and returned back, ensuring the cleanliness of the working fluid. In domestic conditions, these units are not repaired, but are replaced as an assembly or require factory welding.
- 🔥 Heating element (heater): Creates the temperature necessary to begin the process of evaporating the working mixture in the generator.
- 🌡️ Solution heat exchanger: Provides preheating of the lean solution before entering the generator, increasing the efficiency of evaporation.
- 💨 Rectifier: Performs the function of steam purification, preventing water from entering the condenser, which is critical for stable operation.
Professional equipment for regeneration and evacuation
When it comes to service, “evaporation equipment” often means tools for removing moisture and non-condensable gases from the system. Moisture in the circuit is the main enemy, which at low temperatures turns into ice and blocks the capillary.
To remove moisture, a deep vacuum process is used, which is essentially the evaporation of water at low pressure. The main tool here is two-stage vacuum pump. It is capable of creating a residual pressure at which water boils at room temperature and is removed from the system.
It is important to use pumps with high performance, measured in liters per minute (l/min). For domestic refrigerators, models with a capacity of about 60-100 l/min are sufficient, while industrial systems require more powerful units.
Additionally required pressure manifold with a vacuum gauge. It allows you to control the process: if, after closing the valve, the pressure in the system begins to increase, it means that the seal is broken or there is liquid left in the system that continues to evaporate.
Comparison table: standard units versus service equipment
To avoid confusion, let's systematize the data. Below is a comparison of the components that are part of the refrigerator and those required for evaporation work (drying/refilling).
| Component | Purpose | Is it part of the refrigerator? | Need to purchase |
|---|---|---|---|
| Evaporator | Refrigerant boiling for cooling | Yes | Only during repairs |
| Vacuum pump | Removing air and moisture (evaporation) | No | Required for the master |
| Desorber | Evaporation of refrigerant in absorption systems | Yes (in absorption) | Rarely (unit replacement) |
| Recuperator | Collection and purification of old refrigerant | No | For environmentally friendly service |
| Vacuum gauge | Control of vacuum depth | No | Required for the master |
The table shows that external chemical equipment is not needed for the normal operation of a household appliance. All processes take place within a sealed circuit. Buying a vacuum pump is justified only if you plan to carry out repairs professionally.
The role of heat exchangers and condensers in the phase transition process
It is impossible to consider evaporation in isolation from condensation. These two processes are interconnected. After the refrigerant has evaporated in the chamber and absorbed heat, it must be turned back into a liquid. The condenser (black grille at the back of the refrigerator) is responsible for this.
In systems with evaporation (especially in industrial chillers or absorption machines), the efficiency of heat exchangers directly affects energy consumption. Contamination of heat exchangers with dust or scale (in water systems) sharply reduces the efficiency of evaporation.
Cleaning heat exchangers is the only “chemical” procedure available to the user. Sometimes special foam cleaners can be used to remove difficult deposits on the condenser fins, but these are care chemicals and not equipment related.
What is “saturation temperature”?
Saturation temperature is the temperature at which a liquid begins to boil at a given pressure. In the refrigeration cycle, by changing the pressure with the help of a compressor, we change the boiling point of the refrigerant, causing it to evaporate exactly where it needs to be cooled.
It should be remembered that any work with heat exchangers requires caution. Aluminum evaporator tubes are very thin-walled and are easily damaged when carelessly cleaned or attempting to defrost with sharp objects.
Safety and technical nuances when working with refrigerants
Working with equipment for evaporation and charging is fraught with risks. Refrigerants such as R134a, R600a (isobutane) or R404ahave different properties. Isobutane, for example, is explosive, which requires a special approach to equipment (sparking-proof fans, explosion-proof tools).
When evaporating the remaining refrigerant from the system before soldering, you must make sure that the gas concentration in the air has not reached an explosive concentration. For this purpose, gas analyzersare used. Neglecting this rule may result in a fire when heated by the burner.
⚠️ Attention: Never release refrigerant into the atmosphere. In addition to harm to the environment, this can lead to the formation of concentrations in the room that are hazardous to breathing, or to fire (in the case of flammable refrigerants).
It is also important to use the correct oil. Different types of refrigerants require different lubricants: mineral for R12 freons, polyester (POE) or polyvinyl ether (PVE) for R134a and R600a. Mixing oils can lead to a chemical reaction and the formation of acids.
☑️ Check before starting work
Frequently asked questions (FAQ)
Is it possible to use a household vacuum cleaner instead of a vacuum pump to evaporate moisture?
No, absolutely not. A household vacuum cleaner is not capable of creating the required residual pressure (less than 0.5 mbar). Without a deep vacuum, water will not boil at room temperature and will remain in the system, which will lead to the formation of an ice plug and compressor failure.
What equipment is needed to evaporate freon from an old refrigerator?
For legal and safe removal of freon, a refrigerant recuperator is required. This is a specialized compressor that pumps gas into a cylinder. Simply “evaporating” it into the room is illegal and dangerous.
Why is gurgling heard in an absorption refrigerator?
This is the normal sound of the mixture circulating (ammonia, hydrogen, water) in the evaporation and absorption system. It indicates that the boiling process in the generator and the movement of gases are proceeding normally. If the sound changes to a loud noise or hissing, diagnostics are required.
Do I need to buy chemicals to clean the evaporator?
It is impossible and impossible to clean the internal circuit of the evaporator with chemicals without opening the system. External heat exchangers can be cleaned with special foam products for air conditioners, but this is done to improve heat transfer, and not for the evaporation process itself.
What to do if the pressure rises after evacuation?
This indicates a leak in the system (leakage) or the presence of liquid (oil/water) that continues to evaporate. It is necessary to check the connections with a soap solution or a leak detector, and also increase the evacuation time.