“Lisa, in this house, we obey the laws of thermodynamics.”

A notable phrase once uttered by Homer J. Simpson that makes pretty much anyone watching a classic episode of The Simpsons’ sixth season (episode title: The PTA Disbands!) laugh, before stopping for a moment to ask themselves “wait, what is thermodynamics?”

Now, there is no need to worry or start reading science textbooks if you don’t have a clue what it is. Thermodynamics is, in the purest sense, where heat/temperature is used to create changes in the environment. It has four main laws; one better than Newton could muster up when discussing motion, but it’s the first law that requires the most attention: 

Energy in an isolated system cannot be created or destroyed; energy can only be changed.

If you know how to manipulate energy in the form of heat, you can do incredible things with it; from using pressure to heat (and cool) liquids to eradicating the need to use oil or gas at home. Here are some fascinating ways people are using thermodynamics to make everyday life easier.

Heating your home without a flame

If someone looked at your back garden, pointed at the grass and told you it was all you needed to heat your home, you’d think they might be mad. Weirdly though, if you can dig up enough space and lay some pipes down, it’s possible to heat a home without a fire in sight.

It sounds crazy, but the basic process goes like this:

• You put pipes in the ground in a closed-loop
• You pass water and anti-freeze in the loop
• Ground heat is drawn towards the pipes, which heats the liquid
• The now warm fluid passes through a heat exchanger giving that heat to a refrigerant 
• The refrigerant turns from a liquid to gas as temperatures rise
• The gas goes through a compressor, getting even hotter
• That heat then hits another refrigerant, which is linked to your home heating system
• The process starts over

It’s a bit crazy that something so simple isn’t used in every home right now. While it’s a little costly to set up, it means anyone can provide hot water and heat in a building without any emissions.

Giving you perfectly chilled drinks

When you go to get fast food or grab popcorn and soda at the cinema, you’re guaranteed an ice-cold Coke, or whichever drink you like. You might watch someone hit a button and see the beverage getting dispensed from a small nozzle, but there’s a lot of work involved in getting a drink into your cup.

Namely, the pressure required to take a room temperature syrup and mix it with water that needs to be very cold, and have it travel through pipes without the energy and force used causing an increase in temperature that would result with you getting warm fizzy coke.

There is a whole industry dedicated to figuring out ways to use energy in closed cycles to chill and warm things. Star Refrigeration is a Scottish company that does just that. They develop and build self-contained units that use water pressure to heat hospitals, chill food in warehouses and keep your drinks cold. It takes this simple manipulation and figures out how to use it differing scales; you might even be looking at it in play right now if you are reading this in your kitchen with the fridge doing the same thing.

Getting your pizza just right

If something you’re cooking in the oven ever catches fire, there’s one thing you should never do; open the oven door and take it out. It sounds counter-intuitive to do so, but if you did, you would be introducing the small enclosed fire to a massive intake of oxygen and creating an even bigger fire. I’m highlighting this example because its another way we use thermodynamics to manipulate the temperature in a loop, and we’ll take cooking a pizza as the example.

You’ll often find that kitchen ovens are advertised as “convection ovens”. This is a bit of a lie as all ovens heat through convection. When you go to a fancy pizza restaurant, you’ll see a big brick oven in the corner where the flames are in the back. There’s a reason for this. When we heat an oven, hot air is displacing cold air and setting up a convection current. Someone who is an expert at making pizzas can use convection to manipulate the flow of air and cook pizzas in seconds. 

Remember, it’s not the bricks the pizza is on that are cooking it, it’s the transfer of heat via convection that is. On the other side of the coin, it’s the reason why anyone in a Domino’s or Pizza Hut can make sure your pizza is perfectly cooked without having to learn how an oven works, as pizza chains use what are known as conveyor ovens.

Something of a hybrid between an oven and grill, a pizza will pass through one end on a conveyor belt and simultaneously get hit on top and bottom by convecting heat that is drawing cold air in and pushing hot air out.

Who knew that thermodynamics was the reason every Domino’s crust manages to look the same?

So, think thermodynamics is cool now?

The manipulation of energy is (for lack of a better phrase) really cool, whether that’s looking at industrial heat pumps and chillers, or figuring out ways to make the ground under our homes do the hard work for us.

The next time you go to put a frozen pizza in the oven or even boil a kettle, stop and think about the actions going on and how thermodynamics is doing so much while doing so little.