Refrigeration Sucks 20% of the World's Energy Supply

Huge consumption

This is what that august body, the International Institute of Refrigeration said in a 2019 report:

The IIR estimates that the total number of refrigeration, air-conditioning and heat pump systems in operation worldwide is roughly 5 billion. Global annual sales of such equipment amount to roughly 500 billion USD. Over 15 million people are employed worldwide in the refrigeration sector which consumes about 20% of the overall electricity used worldwide.

Yes, 20% of the world’s energy consumption goes on cooling things down — you and me with air-conditioning to keep us comfortable at home, in our offices and cars; beer coolers by the TV; fridges to keep our food fresh or frozen in situ or in trucked supply chains; ships carrying bananas and meat ; LPG Gas transport ships— the list is endless.

And coming up fast on the outside we have data warehouses which need to cool all the servers. Liquid cooling is being developed, but air or liquid it needs cooling.

Countries are struggling to reduce dependence on fossil fuels as coal, oil and gas are boiling up global warming. Our refrigeration systems are spawning rapidly to cope with that increase in global warming.

And this week the world’s 8 billionth child was born

The world population may be growing now at less than 1% per annum but it is still driving energy — and refrigeration — demand.

I’m not sure how they could pin it down to the Dominican Republic, but it must have been somewhere I guess.

World energy demand is growing steadily

Here’s my energy equation, living on a boat

I’m sweltering in 32⁰ C in Indonesia with the occasional day of 90%+ humidity, wishing I had AC (not really), but it’s not practical on my boat. I’d have to buy more fuel to generate more power to run it.

I already have solar panels (900 watts if it’s really sunny) and a wind generator (variable, but little wind here). They are barely enough to run my fridge (which is on a 12 hour duty cycle using freezer blocks) and my freezer. Here in the tropics it’s often cloudy with light winds.

My fridge and freezer are compressor-driven units. I did have a Peltier-effect cool box but that’s not up to the task in the tropics and is power hungry (60 watts). We keep books in it now…

Basically, I use about 240 H (amp hours) a day on average, of which about 180 AH is refrigeration.

To balance it all I need to run a small generator at least 2 hours a day in the tropics— on average - depending on wind and sun. That's because eating 100% dried and tinned food is not something I wish to do long term, and I like cold beer in a hot climate.

When I move, I sail whenever I can but it’s still necessary to use an engine from time to time. As I write I’m waiting for a fair wind to take us from the Spice Islands to New Guinea.

Cutting refrigeration energy demand would be a start

Most refrigeration systems use compressors to compress a refrigerant gas. These gases contribute significantly to global warming and topping up the gas in a fridge has to be done by a licenced technician in ‘advanced’ countries.

Many refrigerants, such as chlorofluorocarbons (CFCs) damage the ozone layer, while others are extremely potent greenhouse gases.

In fact, one kilogram of the refrigerant R410a has the same greenhouse impact as two tonnes of carbon dioxide, which is the equivalent of running your car for six months.

That’s why Australia has specific laws that prohibit the importation of gases like CFCs and regulates the importation of synthetic greenhouse gases.

Refrigerants leak into the atmosphere from faulty or poorly maintained equipment, or when equipment is improperly disposed of. — Australian Government

These gases are pumped through the fridge and allowed to expand, soaking up heat from the contents.

Some (mostly domestic) use the solid-state Peltier effect which is inefficient and expensive.

New technology may help

Recently some researchers in China have demonstrated a solid state phenomenon could make a significant contribution to refrigeration energy reduction.

By applying strain to a composite material using an electric field they can induce a large and reversible caloric effect. This new way of enhancing the caloric effect without a magnetic field could open new means of solid-state cooling and lead to more energy efficient and lighter refrigerators.

Solid-state cooling systems based on caloric materials offer both high refrigeration efficiency and zero greenhouse emissions and are emerging as promising candidates to replace vapour-compression technology. These systems employ a solid material as a refrigerant, which when subjected to an external field (electric, magnetic, strain or pressure) undergoes a change in temperature — a phenomenon called the caloric effect. — Physics World

They have eliminated the need for magnets by combining a Mn3SnC layer with a piezoelectric layer of lead zirconate titanate (PZT)

The caloric (heat transfer) effect was observed by applying an electric field to the material, which induces strain in the PZT via the reverse piezoelectric effect. This strain is transferred from the PZT layer to the Mn3SnC layer, which results in a change in magnetic ordering of the Mn3SnC. This causes a temperature drop of up to half a degree Kelvin in the material which is reversed when the electric field is removed.

There’s a lot more science in this which is beyond the scope of my story here, but is explained in greater depth in Physics World.

How cool is that?

Maybe not enough significantly to help the world energy consumption.

Or my beers.

Conclusion

I was staggered to discover that 20% of our energy consumption is used in refrigeration.

New technology may help, but many of these exotic substrates such as Mn3SnC may be expensive and difficult to fabricate in processes that often have significant carbon footprints.

I think that by the time we see any benefits from this new technology I will long be in Davy Jones’s Locker.

In the meantime I’ll just have to sweat it out.

The researchers, Peng Wu and colleagues at ShanghaiTech University, Shanghai Institute of Microsystem and Information Technology, University of Chinese Academy of Sciences and Beijing Jiaotong University describe their work in Acta Materialia.

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