PROPERTIES OF THE REFRIGERANT
Refrigerants can be characterized by a number of properties. These properties pressure, temperature, volume, density, enthalpy, Flammability, the opportunity to mix with vegetable oil, moisture reaction, smell, toxicity, leakage trend, and leak detection.
Freon refrigerants R-11, R-12 and R-22, plus Амонијак and water, will be discussed in terms of the above categories. Freon R-11, R-12 and R-22 are common Freon refrigerants. Number assigned to the ammonia R-717, while water has a number of R-718.
Притисак
Pressure in the cooling system is important. It determines how reliable equipment should be to keep the refrigerant. The refrigerant must be compressed and sent to various parts of the system under pressure. The main concern is to preserve the pressure as low as possible. The ideal low-side, or evaporating pressure must be near-atmospheric pressure (14.7 pounds per square inch)as possible. This keeps rates опрема доле.
It also has a positive pressure in the system at all stages. With slight pressure, it is possible to prevent air and moisture from entering the system. In the case of vacuum or low pressure, leak suck in air and moisture. Note the five refrigerants and their pressure.
Freon R-11 is used in very large systems, because it requires more refrigerant than other, even if she has the best characteristics of pressure groups. You must consider several factors before a suitable retrofit refrigerant is. There is no идеално расхладно средство for all applications.
Температура
Temperature is important when choosing a refrigerant for a specific job. Boiling point is that the point where the liquid evaporates when adding heat. This, of course, depends on refrigerant and absolute pressure on the surface of the liquid and vapor. Water (R-718) has the highest boiling point. Atmospheric pressure is 14.7 pounds per square inch.
Again, there are no ideal atmospheric boiling temperature refrigerant. However, the temperature-pressure relationships are important in choosing a refrigerant for a particular job.
Запремина
Specific volume is defined as the specific weight of the material. Usually expressed in terms of cubic ft / lb, volume-reciprocal of density. The specific volume of the refrigerant is the number of cubic feet of gas, which is formed when one pound of refrigerant evaporates. This is an important factor to consider when choosing the size of refrigerators-system components. Comparison of specific volumes (up to 5 degrees F) five refrigerants we chose. Freon R-12 and R-22 (the most commonly used refrigerants) have the lowest specific amounts of fumes.
Густина
Density is defined as the mass or weight per unit volume. In the case of refrigerant, it is given in pounds per cubic foot (lb/cubic foot). The density of R-717 (ammonia) is the least...
|