The invention of refrigeration: a brief history

Nowadays, refrigeration is everywhere – from the fridge freezers in our homes to the air con in our offices and the commercial refrigeration systems in shops and supermarkets. Yet it hasn’t always been like this. Here, we’ll talk about the invention of refrigeration, and give you a brief history.

But first…

Why is refrigeration important?

Refrigeration is a must for food preservation. But why?

1. Bacterial activity

Bacterial activity mostly develops between around 5°C and 65°C – depending on factors like the type of bacteria and ambient humidity.

Some bacteria are still active at even lower temperatures. For instance, listeria can still be active at close to 0°C!

This shows that reducing temperatures is an important way to slow down the proliferation of harmful bacteria.

2. Free water fraction

The fraction of free water present in a medium will also play a role in determining microorganism development.

That’s why historically, communities have used techniques like drying and salting to reduce the amount of water contained in food and therefore preserve it.

It’s also why freezing is so effective. Freezing transforms a high portion of the water contained in food into ice, reducing water content in the liquid or free state.

You may also have heard of the vitreous – or glassy – point. This is the point at which the presence of free water is practically zero, giving a powerful bactericidal and virucidal effect – and disrupting almost all enzyme activity.

The temperatures needed to reach this point will vary depending on the food. However, you’re looking at somewhere between -40ºC for ice cream and -80ºC for meat and fish.

The history of refrigeration

Nowadays, when we refer to refrigeration, we often think of fridges and freezers. But refrigeration has been around for thousands of years!

The Egyptians, Greeks and Romans used to preserve snow and ice in natural caves, using it to preserve food during the hotter months.

These snow pits were built in cool, shady places, with straw and sawdust to help with preservation. The snow was also compacted to help it last for longer.

This was a thriving industry that generated employment and wealth for those collecting the snow (boleros), guarding the wells (guardas) and transporting the snow during the coldest hours (arrieros).

So, how did we go from snow pits to fridges and freezers?

The invention of refrigeration

The invention of refrigeration isn’t straightforward. After all, there’s more than one way to cool a medium!

However, here’s a rough breakdown of how refrigeration processes and systems have developed over the centuries.

Experimenting with chemical and physical processes

As early as the 16th Century, endothermic reactions were being used to cool a medium.

We know this because we know that Blas Villafranca – a Spanish doctor based in Rome – was cooling drinks using refrigerant mixtures at this time.

Lowering temperature using endothermic reactions involves combining two or more chemical compounds to create a reaction that absorbs external energy.

In the 17th Century, this technique was further developed by Robert Boyle and the astronomer Philippe Laire.

This led to Daniel Fahrenheit fixing the thermometer in 1715, using a mixture of snow and ammonium nitrate. And later, it led to a scientist named Von Braun freezing mercury to -40 ºC.

Meanwhile, other scientists were experimenting with cooling a medium using physical processes. In this case, the latent heat of vaporisation is used to ‘generate cold.’

In 1748, William Cullen – a physician and chemist – managed to produce ice by vaporising ethyl ether into the atmosphere.

But it wasn’t until the next century that British scientist and inventor Michael Faraday started experimenting with the liquefaction and evaporation of other gases – including ammonia and carbon dioxide (R744), which is still widely used today.

The first refrigeration systems

In 1842, another doctor called John Gorrie devised and built the first closed-cycle refrigeration system, with the aim of cooling the rooms of yellow fever patients.

The system relied on the mechanical recompression of evaporated refrigerant gases.

Later, in 1851, he obtained a patent for an ice-making machine using the same concept, which continued (with some variations) until 1950.

Meanwhile, commercial refrigeration was just getting started. This is largely credited to Alexander C. Twinning, an American businessman, who initiated it in 1856.

Shortly after, an Australian, James Harrison, examined both Gorrie and Twinning’s refrigerators and introduced vapour-compression refrigeration to the brewing and meat-packing industries.

Then, a Frenchman named Ferdinand Carré developed an even more complex system in 1859. Instead of using air as a coolant, he used rapidly expanding ammonia, which liquefies at a much lower temperature and can therefore absorb more heat.

The spread of refrigeration

Carré’s refrigerator systems became widely used, and vapour-compression refrigeration is still the most common method of cooling today.

However, ammonia was toxic if leaked, while other refrigerant gases used – such as methyl formate and sulphur dioxide – were to a large extent corrosive, poisonous and highly explosive.

This led to a search for alternative refrigerant gases and ultimately, the development of a number of synthetic refrigerants in the 1920s – including CFCs, often known as Freons.

Freons can be credited with providing the impetus for the introduction of domestic refrigeration systems.

After all, they made domestic refrigerators almost completely risk-free – as well as affordable for middle-class American families.

From here, domestic refrigeration quickly spread to much of the world.

Refrigerants and the environment

Freons brought many benefits to the development of refrigeration. However, it wasn’t long before people started to realise that these chemical refrigerants were damaging to the environment.

In the 90s, alternative F-gases known as HFCs (hydrocarbons) were introduced as a way of replacing other gases that were harmful to the ozone layer.

But it soon became clear that these too have a major impact on climate change.

Fluorinated gas regulations were first introduced in the EU in 2006, and have since been amended twice.

They:

• Set standards for leak prevention, recovery and reporting
• Phase down the use of HFCs
• Limit the overall GWP of gases that can be sold in the EU
• Restrict the use and sale of equipment containing high-GWP F-gases

Other countries have similarly implemented programs to reduce the impact of refrigerant gases on the environment – such as the American Innovation and Manufacturing (AIM) Act in the US and Canada’s detailed strategy to manage HFCs.

Meanwhile, the UK initially adopted EU F-gas regulations into domestic law to ensure continuity in the post-Brexit period – although it’s yet to be seen how close the UK’s stance will be to the EU’s latest amendment.

Refrigeration today

In the face of tightening F-gas regulations, the UK refrigeration industry turned to natural alternatives around 12 years ago.

Natural refrigerants aren’t just better for the environment. They’re also high-performing, making them a win for both people and the planet.

Today, the most common refrigerant gases used in refrigeration include:

• R404A
• R454A
• R448A
• R449A
• R134a
• R513A
• R450A
• R290
• R152a
• R744
• R717

These refrigerants all have zero ozone depletion potential.

However, their global warming potential (GWP) varies hugely, from 1 to a whopping 3,922!

At Clade, we use the natural refrigerants CO2 (R744) and propane (R290).

These refrigerant gases both have a very low GWP – in fact, CO2 has the lowest GWP of all the refrigerants, at just 1! This is in contrast to synthetic refrigerants that commonly have a GWP of several thousand.

Make us a part of your company’s refrigeration history

If you’re ready to add a green refrigeration system to your business premises, you’re in the right place.

At Clade, our commercial refrigeration systems contain CO2.

This naturally occurring refrigerant gas is environmentally friendly, non-toxic and non-flammable – and it performs excellently in refrigeration systems.

Simply get in touch with our team of experts to find out how we can help. We’d be happy to design, manufacture and install a refrigeration system that’s perfect for your needs.