So, imagine that this steel vessel replaces the water line entering your house. (If you don’t collect rainwater or make water from hydrogen and oxygen, you may have one.) If it gets too cold, the water can freeze and literally explode your pipes. That’s bad. Now for some questions and answers.
Why doesn’t this happen more often in the south?
Residential water lines are almost always underground – and that’s a good thing. While air temperatures can vary greatly from summer to winter, ground temperatures are much more stable. In the southern states, the temperature of this soil is not very prone to freezing – so water in the pipe will also be above freezing (and stay melting).
But there are some exceptions. In some places with a warm climate, not all parts of a water pipe system will be underground, and it will pass through air sections. (Heck, I have water pipes in my loft, and I live in a warmer place). Although there is a small temperature difference between cold water (say 1 degree Celsius) and warm ice (0 C), there is a big difference in energy. It takes some energy to convert water from the solid to liquid. This is the hidden heat of fusion. For water, it is worth 344 goules per gram. That might be hard to understand, so what about an example?
Osbarr you have a liter of ice (with a mass of about 1,000 grams). If you want to take this ice at 0 C and turn it into water at 1 C, it would take 344,000 joules of energy (plus a little more energy to raise the water temperature). What energy is that? Well, let’s say you have a smartphone with a 3,000-mAh (milliamp-hours) battery. This equates to 41,000 joules. So it might have enough energy to run your phone for a whole day, but you would need eight or nine of those phones to melt that ice.
It ‘s definitely a good thing. It means you can melt ice to cool your drinks – and you don’t need that ice. That also means you have to remove a lot of thermal energy from your pipes in order for them to freeze. One cold night may not be enough to make your pipes burst.
Does it help to leave the faucet running?
There is. Okay, just think you’re inside a water pipe. (Yes, you are a tiny bit now.) If the rain stops, you may be stuck in a part of the pipe that is exposed to cold air. You could actually freeze, and then you had to break the pipe. But now it may be running water, caused by a faucet that is slightly drying. You’re still a tiny little man inside a pipe, but now you’re moving. You go through the piece of cold pipe and you get cold – but you don’t freeze. Instead, you just move on to other parts of the house.
Oh, but more water from the underground main line is coming into that cold part of the pipe. Would it freeze? It’s not so similar. Remember, the water pipe is at ground temperature, and it is almost certainly not lower than freezing. So the incoming water isn’t terribly cold, and hopefully it won’t freeze.
What about insulation?
Insulation helps. If you put a layer of foam cover around any open pipes, it will do the same thing with your cooler or insulated beverage cup. The insulation reduces the rate at which energy is transferred from the hot object to the cold object through thermal interaction. If you put a cold drink on board, energy is transferred into the drink to cause a rise in temperature. Putting the drink in a refrigerator, on the other hand, increases the insulation and reduces the rate of energy transfer so that it takes longer for the drink to warm up.