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How did ancient people cool off in the face of unbearable summer heat?
Certainly not like modern people can enjoy the comfort of air conditioning and refrigerators, ancient people can only sit on a mattress at home, or swim in rivers and lakes to cool off.
Of course, there are also wise men who know how to make their own ice to beat the heat.
So how did ancient people beat the heat by making ice?
1. How ancient people made ice.
The ancients also used a variety of ice-making methods, including ice cellars and ice wells.
The production method of the ice cellar is also very technical, it requires rivers and lakes underground, and then dig some underground "cellars" in summer, spread hard soil or lime and other materials in the cellar to prevent water seepage, and then spread a layer of organic materials such as wheat straw on top to prevent the ice from directly touching the soil and causing melting, and then bring the cold air in the cellar into the cellar using the underground river, and then put the ice into the cellar.
Ice wells, on the other hand, are made in a more simple and crude way, only digging a well underground, and then digging a channel where there is a river in the lower part of the well, allowing the river water to enter the well, and forming an ice wall in the well, so that the ice can be dug out in the winter to make ice.
Of course, both of these methods of ice making are very labor-intensive, and ice cellars and ice wells also take a lot of time to make, and most places in ancient times did not have rivers and lakes, so they only appeared in some places.
In addition, the ancients also had a more labor-efficient way of making ice, that is, using boiling water to make ice.
There is a record in the "Huainan Wanbi Book", that is, the water is put into the stone basin, and then the stone basin is put into the pot of boiling water, and after boiling the water, the stone basin is taken out and the hot water is poured out, and the bottom of the stone basin will freeze at this time.
How does this work out?
Scholars have experimented with this method and found that the bottom of the stone basin will cool down quickly after pouring hot water, but it cannot reach the freezing point, and only by constantly stirring the water during the cooling process and oxidizing the air in the water can the temperature in the water reach zero degrees, and then ice cubes will be formed.
How did the ancients do this?
Since the dissolved oxygen in the water is released as the temperature increases, when the dissolved oxygen in the boiling water is released, it absorbs the surrounding heat, causing the temperature at the bottom of the stone basin to decrease rapidly.
So how did the ancients pour out hot water?
Scholars have found through experiments that when the water temperature reaches about 85 degrees, it will become very thin in an instant, so it only takes a small amount of effort to pour out the hot water, but the water temperature at this time will also bring the temperature at the bottom of the stone basin to about 60 degrees, and then the air in the water can be oxidized by stirring, so that ice cubes can be made.
Second, the working principle of the refrigerator.
So how does the refrigerator release the cold air into the room?
The working principle inside the refrigerator is similar to that of an air conditioner, there is a compressor, which drives the compressor through an electric motor to increase the pressure of the refrigerant, thereby increasing the temperature of the refrigerant, and then puts the hot gas in the refrigerant outside, and then dissipates the hot air through the radiator to reduce the temperature of the refrigerant, and at the same time produces a large amount of cold air, reduces the temperature of the refrigerant through the condenser, and then makes the refrigerant evaporate inside through the evaporator, so as to absorb the heat from the outside and play a refrigeration role.
The working principle of the refrigerator can be roughly divided into three parts, one is the compression part, which increases the pressure of the refrigerant through the compressor, and then dissipates the hot gas, reducing the temperature of the refrigerant and increasing the pressure of the refrigerant at the same time.
The other is the heat dissipation part, which allows the hot air to be dissipated through the radiator, reducing the temperature of the refrigerant, and also playing a role in cooling at the same time.
The last part is the evaporation part, where the refrigerant is evaporated inside through the evaporator while absorbing the hot air from the outside.
But some people will have questions, so the refrigerator is by dissipating the heat of the refrigerant to the outside, and then evaporating the refrigerant inside through the evaporator, while absorbing the heat from the outside, so is the indoor temperature constantly rising?
This involves a physical principle, the second law of thermodynamics.
The second law of thermodynamics states that heat cannot be transferred from a colder object to a hotter object on its own, which means that even if the refrigerator can continuously cool down internally, the heat emitted by the radiator will not automatically flow from the cooler place to the hotter place, so the temperature of the whole room will not change significantly.
But the refrigerator releases a lot of heat when it is working, what will happen to this heat?
Generally, the refrigerator dissipates the released heat to the outside through the radiator, but not all of this heat can be dissipated through the radiator, and some of the heat will fall on the outside of the refrigerator, which is why the outside of the refrigerator will be hotter.
However, the heat released by the refrigerator will not flow into the room, so the temperature inside the refrigerator will not be affected, but the temperature outside the refrigerator will be relatively high.
3. Energy saving and environmental protection of refrigerators.
So does the heat released by the refrigerator affect the temperature in the room?
Generally speaking, this effect is very subtle, but when the indoor temperature is relatively high and the refrigerator releases more heat, the temperature inside the refrigerator may be a little higher than normal.
Therefore, refrigerators are generally placed in a ventilated place, so that the heat can be better released.
Refrigerator as a frequently used electrical appliance in daily life, although we do not need to understand the working principle of the refrigerator, but occasionally understand is also very interesting, the refrigerator can only ensure the low temperature of the room, but can not ensure the low temperature of the overall environment, so after opening the refrigerator in the summer, the indoor is much cooler, but the outdoor temperature has risen a lot.
Therefore, it is necessary to maintain a certain distance from the refrigerator, and the refrigerator also needs to be cleaned regularly, so as to ensure the service life of the refrigerator.
The wisdom and creativity of the ancients have brought us all kinds of inspiration, although we can more easily refrigerate through air conditioners and refrigerators, but the ancient people's ice-making methods are also part of human understanding of natural phenomena, and these understandings are also something that we need to learn and protect.
And nowadays people also advocate energy conservation and environmental protection, so the use of electrical appliances should also pay enough attention to avoid unnecessary energy waste.
epilogue
While discussing the ancient ice-making methods, we should not forget the understanding and utilization of natural phenomena by ancient people, which has important implications for the development of human science.
For the development and use of modern science and technology, it is also necessary to understand and use the working principle of electrical appliances more scientifically and reasonably to avoid unnecessary waste of resources and environmental pollution.