In 1850, Edmond Carr developed the first absorption machine, which used the exothermic reaction of water and sulfuric acid. An absorption refrigerator is a refrigerator that uses a heat source to provide the energy needed to drive the cooling process. Whilst an advantage is that sulfuric acid could be easily produced commercially by the reaction of water with sulfur trioxide, its reactivity was a major disadvantage and led to its phasing out. Sulfuric acid is a powerful oxidizing agent and reacts with many metals at high temperatures, and the very exothermic addition of water to concentrated sulfuric acid could lead to explosions.In 1859, Ferdinand Carr demonstrates an ammonia and water refrigeration machine. In this system ammonia is used as the refrigerant and water is used as the absorbent. The ammonia-water solution is highly stable with many materials, however it corrodes copper and its alloys. Categorized as a natural refrigerant, ammonia is environmentally benign. It has both GWP (Global Warming Potential) and ODP (Ozone Depletion Potential) equal to zero, meaning it does not deplete the ozone layer and does not contribute to the warming of Earth. Ammonia was considered to be the most suitable refrigerant, however, due to its high toxicity its applications are limited. Exposure to high concentrations of ammonia in air causes immediate burning of the nose, throat and respiratory tract.
In 1866, Chemogene, a mixture of petrol ether and naphtha was patented as a refrigerant for vapor compression systems. It has high volatility and is easily sourced by distilling petroleum, an abundant fossil fuel. However, it was extremely flammable, and just like ammonia was highly toxic, with inhalation overexposure causing negative effects on the central nervous system. In the same year, Carbon Dioxide was introduced as the first gaseous refrigerant. It was non-flammable, yet had the disadvantage of having to be operated at high pressure from around 30 to 200 atmospheres in order to operate as a refrigerant. This required the use of heavy steel tubing. Whilst carbon dioxide has an ozone depletion potential of 0, its GWP is exactly 1 (the baseline unit to which all other greenhouse gases are compared) and its atmospheric lifetime is 29,300-36,100 years, meaning it remains in the climate system for an extremely long period.
Sulfur dioxide (R-764) was first used in vapour-compression refrigeration in 1875. Although it absorbs heat well (high specific heat) during evaporation and dissolves oil, sulfur dioxide is not safe when used in large quantities because it is toxic and reactive. It has no ODP and GWP due to not being a greenhouse gas yet is it is still an environmental air pollutant, causing acid rain and atmospheric particulates.
Towards the end of the first generation, Chloromethane(R-40) production began in 1878, before Dichloroethene (R-1130) in 1926. Used in vapour-compression systems, Chloromethane is a colorless extremely flammable gas with a mildly sweet odor. It was phased out due to concerns about its high toxicity and extreme flammability. It has an ODP of 0.2 and a GWP of 13, however these were properties that had not yet been taken into account at this time. Willis Carrier used Dichloroethene (R-1130) in his first centrifugal compressor which was seen as a technological advancement for refrigeration. R-1130 has no ODP or GWP and has a sharp, harsh odor for the detection of leaks. However, it is highly flammable, toxic and not compatible with strong oxidizers. Ultimately, whilst the effects on the environment by first generation refrigerants were often negligible, their safety hazards were reasons for their phasing out.