When turning on air conditioner in summer, should we use internal circulation or external circulation?

The use of internal circulation and external circulation can not only make driving cooler in summer, but can even adjust fuel consumption and save a lot of fuel costs.

I will teach you how to do this today in this video in three minutes. I suggest that my friends like and bookmark.

First of all, we need to understand fundamental difference between internal and external circulation.

It's actually a bit like turning on an air conditioner at home. Internal circulation consists of closing windows and turning on air conditioner. Although cooling effect is good and energy is saved, air is not easy to get stuffy?

External circulation is to open windows and turn on air conditioner. Although air is relatively circulated, cooling effect will be relatively low, and the cost of electricity is also high.

Knowing difference between internal and external circulation, we can choose air conditioning mode according to needs of different scenarios.

For example, let's say car has been out in sun in summer, and if you want to cool down quickly, you can use first outside, then inside method.

Temperature after exposure to sun is very high. Zhang Li from Jilin University completed his master's thesis "Technology for detecting volatile organic compounds, aldehydes and ketones in vehicles under natural exposure."

The data above is ambient temperature is 34°C, after black luxury car is exposed to sun, air temperature will reach 72.9°C, guess what.

That is, temperature in car can be more than 30°C higher than ambient temperature. At this time, internal circulation and cooling of air conditioner is turned on, and effect is actually rather weak.

What is a relatively reasonable approach? That is, first open windows of car, turn on outside circulation, and let air conditioner blow out air to remove heat from the car first.

Wait until temperature in car drops to about ambient temperature, then turn on cooling of air conditioner and internal circulation. In this way, cooling effect will be much better than turning on internal circulation and air conditioning as soon as you get into car, and this will save money.

If car is cold, we may consider using internal circulation to save fuel.

Li Yiheng from Jilin University completed his master's thesis on "Load Detection and Application Analysis of Internal and External Cycles of Automotive Air Conditioning".

The data above shows that when switching from internal circulation to external circulation, cooling load will increase by 191.8%.

This is same as turning on air conditioner in room, if you open window and turn on air conditioner, air conditioner will also cool hot air coming in from outside, and energy consumption will naturally decrease. be higher.

However, internal circulation cannot be on all time. The space inside a car is different from room at home. There is not enough space inside car. If internal circulation is turned on for too long, carbon dioxide concentration will be too high, making driver dizzy and drowsy.

Thus, if internal circulation is turned on for about half an hour, it can be turned off manually to allow air in car to flow in order to avoid excessive concentration of carbon dioxide and affect driver's condition.

This feature is now available in many new vehicles.

In addition to internal and external circulation, air conditioner also has temperature control, how to set this number? The smaller number, steeper? The colder, the more fuel?

If you have any questions about car air conditioners, please leave a message in comments area and discuss it together.