Then, stretch it very hard and quickly apply it to your temperature-sensitive upper lip. I think it feels warmer than before. This is because it adds energy to the rubber band, increasing its temperature.
Ready to get to the cool part? Let it stretch out a bit until it comes back to room temperature. Then loosen the elastic band and immediately touch your lips again.it's snowing colder Better than room temperature! Seriously, try this yourself.
So, if you have a big enough rubber band, can you use it to cool your house? Wait a minute, you say. “In the first stage, when we stretched the rubber band, it got hot, and then it returned to its original temperature. And in the process, the rubber band returned to its original temperature.” heated air. you're right. But what if you could vent that warm air outside? Then you could keep only the cooling stage inside.
boom. You've reinvented the air conditioner! Instead of rubber bands, air conditioners have a fluid called refrigerant that circulates from inside to outside in a closed loop. This fluid has a low specific heat, so it changes temperature quickly and has a very low boiling point, turning into a gas at around -15 degrees Fahrenheit.
How is it going? The gas is first compressed and heated to about 150 degrees. As the hot gas is circulated through a series of copper coils located outside with a fan blowing on it, the gas loses heat energy to the atmosphere. (Copper also has a low specific heat.)
It is then pumped back inside, where the pressure rapidly drops and it expands, instantly cooling it to about 40 degrees. As the cooled fluid circulates through coils in the room, a fan blows warm room air onto it, reheating the fluid and cooling the room air in the process. As the system cycles, it essentially picks up heat energy indoors and transports it outdoors.
By the way, this is the exact same process that refrigerators use to keep cheese and soda cold. In both cases, this process causes things inside to become cooler and things outside to become warmer. Just put your hand behind the fridge and you'll see what I mean. Just as a joke, I'd like to introduce you to a person who actually made a refrigerator that runs on rubber bands.
So heat pumps aren't new.
You thought this was going to be an article about heat pumps, right? Well, guess what? We've been talking about heat pumps all this time. Because heat pumps work on the same principle. A heat pump, like an air conditioner, cools your home by circulating a refrigerant and changing the pressure to change the temperature. So we take heat energy from one place and put it somewhere else.
Now, back to the big mystery. How can a heat pump increase the temperature of indoor air on cold days without actually producing heat? Simple: just do it in reverse. This time, we will cool down the high temperature compressed refrigerant inside the house to raise the indoor air temperature. The cold gas at low pressure exits to be warmed.
Do you want to warm up outside? yes. Even on sub-zero days, there is thermal energy in the air. As long as it's above absolute zero, believe me, it's about minus 460 degrees Fahrenheit, the air molecules are in motion. And by cooling the refrigerant to temperatures below winter temperatures in most places, say -15 degrees Celsius, heat energy is squeezed out of even the frigid air.
Of course, energy cannot be obtained for free. Heat pumps use electricity to drive a compressor and fan. But if you have solar panels on your home, or if even some of the electricity in your area comes from non-carbon sources, replacing your gas furnace with a heat pump can make a big difference in reducing greenhouse gas emissions. may occur. And you'll probably lower your energy bills in the process.
