the earliest commercial fridges early NUMBER_TOKENth century would have been about NUMBER_TOKEN pounds that sort of price and compare compared to a model t fold which was maybe NUMBER_TOKEN pounds so more expensive than a car so early fridges were the plaything of the edwardian rich and did not become affordable to the masses until much later and how did it work refrigeration uses the principle of evaporation of a liquid to gas to produce a cooling effect if i can show you a little experiment in this cam we've got some butane which is a common refrigerant that we use today if we spray it you can see it actually produces cooling as it hits the surface and evaporates well yes at first it's warm but then it gets really cold very fast the evaporating gas draws heat this is how a fridge works the edwardian engineers understood they needed to create a cycle where a gas could evaporate draw the heat and return to liquid continuously the refrigerant would have been in this pipes here and would have made this small container within here cold just this little thing in the middle here absolutely i know it's huge isn't it the whole machine is massive just for a small amount of cooking yes you can put a pint of milk in there and that's about it that's it what's all this then well that's basically making the refrigerant back to a liquid again we've got a compressor that pumps it but this is a hand driven one so you'd have had a servant driving this that's a terrible job that's awful you mean you have to be doing this all day NUMBER_TOKEN hours a day if you wanted to keep that point to melt cold absolutely it took time for the technology to develop to cope with the chemicals they knew could work this prototype was developed before electricity and well before rubber sealants you can see here you know the sort of components that we would have used the refrigerant wouldn't have stayed within the system so they leaked out the trouble was that the early fridges weren't actually sealed fridges so they used these gases and there would be a certain amount of seepage and leakage from these fridges and this is what made the early fridges so hazardous the dangers of the early fridges were actually in the chemicals that they used as the refrigeration the pneumonia which was pretty flammable and pretty toxic if you breathe in ammonia gas it's immediately very toxic so the eyes would start to water your throat would become sore it can cause chest pain difficulty in breathing and if you have enough of it it can cause circulatory collapse and even death you had sulfur dioxide which was extremely toxic and then you had methyl chloride only certain gases will turn from liquid to gas in the way required unfortunately these properties also made them exceptionally dangerous gases like methyl chloride also had other uses they actually used gases that in the first world war i used unfortunately used to gas people in the trenches he took ill after repairing a burst pipe in a refrigerator medical evidence showed that death was directly due to inhaling ammonia fumes if you have any length of period being exposed to these gases then you can get frostbite on the inside of your lungs your blood can pool on your heart you were talking absolutely lethal materials to be using in the fridge so not only were they poisonous but they could be a fire hazard these chemicals were volatile
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