How does the fan blow the coolest?A physical experiment tells you the answer

In summer, one of the most thoughts about people is how to cool.

Blowing air conditioners can easily cause "air conditioning diseases" such as dizziness and nasal congestion. The cooling effect of blowing fans is slightly worse. How should I choose?

In fact, the fan is not only cooler, but also accelerate air circulation. "Life Times" (search "LT0385" in WeChat can be followed) to interview experts to tell you how to healthy summer heat in summer.

Interviewed expert

Han Shuhua, chief physician of the Department of Respiratory and Critical Medicine, Affiliated to Zhongda Hospital Affiliated to Southeast University

Tang Chengchun, chief physician of Cardiovascular Medicine, Affiliated to Southeast University

Zhang Yan, Consumer Guidance Department of the China Home Appliances Association

The fan blows out the window and it is cooler

Before the content of today, let's first understand a physical knowledge point -the law of Bernoulli.

In 1738, Daniel Bernubari, known as the "Father of fluid mechanics", discovered the "Bernoulli law". This principle can be understood this: in a fluid system, such as airflow and water, the faster the flow rate, the smaller the pressure of the fluid generated.

To put it simply: In general air flow, the larger the flow rate, the less pressure.

This principle can also be used in life, for example, cooling the room. A physics teacher abroad tells the reason

In the sweltering summer night, blowing the electric fan at the open window, the air in the room was blown out, and the room became a low -voltage area. The relatively static air outside the window would flow into the house because of high pressure. Essence

The fresh and cool air outside continues to enter the room, promoting the circulation of air, bringing a cool and light feeling.

You can also open a window on the shade surface of the house at the same time, which can also suck the cool air outside.

What needs to be reminded is that the fan should not be close to the window, and pull a little distance. When the outdoor temperature is lower than the indoor temperature, it can have a significant cooling effect. If the outdoor temperature is higher than the indoor temperature, this may make the indoor temperature higher and higher.

Air conditioning or fan, how to choose?

The air conditioner is a series of internal processing, which blew the steam into cold air to reduce the indoor temperature. The fan is to drive air flow and circulation. With the help of moisture evaporation and take away the heat to reduce the temperature, it makes people feel comfortable.

These two ways of cooling each profit and disadvantages:

01

air conditioner

◎ You need a relatively sealed environment to meet the requirements of cooling, which is easy to make people feel boring;

◎ Dry the indoor air, it is easy to make people stuffy nose, dry throat, sneezing, etc.;

◎ In addition to the filter, the internal dehumidification devices, evaporators, etc. also need to be cleaned, and the operation is more complicated;

◎ Air conditioning is the "big power consumption" of each family, and it will become the main force of electricity bills in the summer.

02

fan

◎ When the heat is unbearable and the air humidity is high, it will feel that the fan is blowing out of the hot air;

◎ The wind blows to the face for a long time, leading to facial neuritis, which may cause crooked mouth and eyes. Blowing to the body can easily cause diseases such as wind, cold, abdominal pain, diarrhea and other diseases;

◎ The acceleration of air flow can easily cause body fluid to lose fast.

If the temperature is not very high, if the morning or evening, you can choose an electric fan. In addition, for people who do not like to blow air conditioners and those who are more stuffy in the room, it is recommended to use a fan, which is not only conducive to air circulation, but also cools down.

If the temperature is high, for example, the indoor temperature exceeds 32 ° C, and the air humidity is large, the selection of air conditioners is better, which can not only reduce the room temperature, but also remove indoor moisture.

Do this scientific cooling in summer

You can usually try to achieve the following points so that you can avoid being hurt by "cooling" while enjoying coolness.

26 ℃ in the house is good

The indoor temperature in the summer is best not less than 26 ° C, the indoor humidity is maintained at about 60%, and the temperature difference between indoor and outdoor temperature is best not to exceed 3 ° C to 5 ° C. Different people have different tolerances of temperature and can be adjusted appropriately. Avoid being blown by the wind

Air conditioners or fans should avoid direct blowing or blowing in a direction. People who are closer to the air outlet, spare parts long -sleeved clothes or shawls, pay attention to protecting the neck, shoulders and wrists, and avoid being blown by the wind.

Protect the key parts

Cervical spondylosis, lumbar disc herniation, arthritis, gout, and trauma positions can induce symptoms when cold, such as pain and stiffness. Pay attention to the warmth of these parts.

Sleeping mats, especially bamboo mats, can absorb some heat. However, if you sleep in the air -conditioned room, it will be cooler, which may accelerate bone pain or other symptoms.

Keep clothes dry

The humidity in the summer is high, and the clothes should be kept dry. It is best to change the sweat in time.

Pay attention to replenishing moisture

It is often necessary to cause water loss in the air -conditioned room, and the blowing fan is more likely to cause body fluid loss. Therefore, it is necessary to replenish more water. The water temperature should not be too cold or overheated. Warm water at 35 ° C to 40 ° C is the best choice.

Open more windows ventilation

When using the air conditioner, ventilate the room once every 2 to 3 hours, and ventilate for 10 ~ 15 minutes each time. In addition, while turning on the air conditioner, you can open a small seam away from a window away from the air conditioner to ensure indoor air circulation.

Give your eyes a little warm

Dry eyes are common "air conditioning diseases", and people wearing contact lenses or chronic conjunctivitis are more susceptible to trouble. In addition to moderate drops of eye drops, you can also apply warm towels to help slow down the symptoms.

Equipment should be cleaned regularly

A large amount of dust will be gathered inside the air conditioner. If it is not cleaned in time when used, it may cause allergies, cough, pneumonia and even chronic diseases. The fan blades of the fan also need to be cleaned regularly.

It can be cleaned once before, during use, and no longer in use.

The following three types of people should be careful when using the air conditioner:

◎ Elderly: Sudden cold or sudden heat can induce cardiovascular and cerebrovascular diseases, and the air conditioner is best to turn to about 28 ° C. Dizziness, disorder of consciousness, and lack of memory must be vigilant.

◎ Children: Children can try not to use air conditioners. Even if they are used, they must stay away from the air conditioner. You can touch your hands, feet, and neck to pay attention to your child's body temperature.

◎ Women: Women with weak bodies and middle -aged and elderly women, when they blow the air conditioner, they have cold bones, accompanied by pain and cough. It is best not to blow the air conditioner.

Editor in this issue: Wang Xiaoqing

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