Classification of Refrigerant According to Applications

Classification of Refrigerant According to Applications Points : classification of refrigerant according to applications, primary refrigerants, secondary refrigerants, halocarbon compounds, azeotropes, hydrocarbons, inorganic compounds, unsaturated organic compound The refrigerants are classified as follows:
1. Primary refrigerants
2. Secondary refrigerants 1. Primary Refrigerants Primary refrigerants are those working medium’s or heat carries which, directly take part in the refrigeration system and cool the substance by the absorption of latent heat e.g.. Ammonia, Carbon dioxide, Sulphur dioxide, Methyl chloride, Methylene chloride, Ethyl chloride and Freon group etc. 2. Secondary Refrigerants Secondary refrigerints are those circulating substances which are first cooled with the help of the primary refrigerants and are then employed for cooling purposes, e.g.. ice, carbon dioxide etc. These refrigerants cool substances by absorption of their sensible heat.
The primary refrigerants are grouped as follows: (i) Halocarbon compounds In 1928, Charles Kettening and Dr. Thomas Mighey invented and developed this group of refrigerant. IN this group are included refrigerants which contain one or more of three halogens, chlorine and bromine and they are sold in the market under the names as Freon, Genetron, Isotron and Areton. Since the refrigerants belonging to this group have outstanding merits over the groups refrigerants, therefore they find wide field of application in domestic, commercial and industrial purposes.

The list of the halocarbon refrigerants commonly used is given below:
R10 — Carbon tetrachioride (CCl₄)
R11 — Trichioromono fluoro methane (CCI₃F)
R12 — Dichloro-difluoro methane (CCI₂ F₂)
R13 — Mono-bromotrifluoro methane (CBrF₃)
R21 — Dichloro monofluoro methane (CHCI₂F)
R22 — Mono chloro difluoro methane (CHClF₂)
R30 — Methylene-chloride (CH₃Cl)
R40 — Methyl chloride (CH₃ Cl)
R41 — Methyl fluoride CH₃F)
R100 — Ethyl chloride (C₂ H₅Cl)
R113 — Trichloro trifluorothane (C₂F₃Cl₂)
R114 — Tetra-fluoro dichloroethane (C₂F₄Cl₂)
R152 — Difluoro-ethane (C₂H₆F₂) (ii) Azeotropes The refrigerants belonging to this group consist of mixtures of different substances. These substances cannot be separated into components by, distillation. They possess fixed thermodynamic properties and do not undergo any separation with changes in temperature and pressure. An azeotrope behaves like a simple substance.

Example R-500. It contains 73.8% of (R-12) and 26:2% of(R-152). (iii) Hydrocarbons Most of the refrigerants of this group are organic compound’s. Several hydrocarbons are used successfully in commercial and industrial installations. Most of them possess satisfactory thermodynamic properties but mare highly inflammable. Some of the important refrigerants of this group are:

R50 — Methane (CH₄)
R170 — Ethane (C₂H₆)
R290 — Propane (C₂H₈)
R600 — Butane (C₄H₁₀)
R601 — Isobentane [CH(CH₃)₃] (iv) Inorganic compounds Before the introduction of hydrocarbon group these refrigerants were most commonly’ used for all purposes.

The important refrigerants of this group are:
R7 17— Ammonia (NH₃)
R718—Water (H₂0)
R729 — Air (mixture of 02, N2, CO2 etc.)
R744 — Carbon dioxide (CO₂)
R764 — Sulphur dioxide (SO₂) (v) Unsaturated organic compound The refrigerants belonging to this group possess ethylene or propylene as their constituents. They are:

R1120— Trichloroethylene (C₃H₄Cl₃)
RI 130— Dichloroethylene (C₂H₄ Cl₂)
R1150 —Ethylene (C₃H₆)
R1270 — Propylene