The majority of us take air conditioning for granted nowadays, but the origins of these units will surprise you. For example in America in the cooling plants, rather than using the refrigerants that we are used to today they actually used ammonia! It wasn’t until the 1920s when it was decided that a safer option would be a refrigerant of some kind. As soon as this was developed air conditioning was installed in cinemas, shopping centres and government buildings in America. Continue reading →