Air Conditioning Mini Split. Restricted Industrial uses. 

The first refrigerant used to gather several of these features and be the only ones available when the first production machines cold mechanics (1867), were the ammonia (NH3), carbon dioxide (CO2) and sulfur dioxide (SO2) . But these refrigerants had big problems of toxicity, explosion and corrosion on the premises so that its use was restricted to industrial uses. 

Mini Split Carrier. Freon. 

Ammonia Except, all these are no longer used refrigerants being, replaced by called freon, they appearing on the market from the year 1928 and do not have the drawbacks of the first. 

Senville Mini Split Heating and Cooling. The Effect Refrigerator. 

Today it is still used in large systems because it is known refrigerant  that have the effect refrigerator higher. It is one of the less expensive and easily available and has high chemical stability. Is immiscible with the oil, so it must be used an oil separator in the discharge line from the compressor to the condenser. 

Mini Split Air Conditioner. Disadvantages. 

One drawback: it is toxic, something flammable and can be explosive in high concentrations, but can be easily detected by smell,so these drawbacks is of little importance in industries with high level of control.