Do you think it's strange? Sometimes the air conditioner is turned on for a long time, but the room is still hot and cold unevenly. It's like it's so cold that people are shivering here, but it's as hot as a steamer over there. What's the secret behind this temperature?

Let’s talk about the temperature distribution first. Have you ever noticed these situations: In a place with central air conditioning, it is so cold under the air outlet that it can freeze people into ice sculptures, but it is as hot as a small stove in the corner; in a floor heating room, when you step on the floor with bare feet, sometimes a coolness suddenly comes from the seams of the tiles, startling you; and in the office, someone shouts that the air conditioner is not cold, but someone quietly puts on a blanket. Behind this, there is actually a university student in the field of HVAC. ——Fluid temperature distribution. Today we will talk about this in plain language, so that you can use science to defeat this annoying "unequal hot and cold".

Let's talk about fluids, which are air or water. When they flow in pipes, they have two completely different "characters" just like people.

There is a type called laminar flow, which is like that kind of particularly well-behaved top student, lining up and moving forward in an orderly manner. At this time, the temperature stratification is obvious. The cold air sinks below and the hot air moves to the top. This is the case when the air conditioner blows out air at low wind speed and the floor heating pipe slowly circulates. But there is also a problem. As a result, people tend to have cold feet and hot heads, and the temperature difference can be 3 to 5 degrees Celsius!

There is another type called turbulence, which is like a wild rapper. The fluid is rotating and mixing wildly inside, and the temperature distribution is more uniform. How to trigger turbulence? Increase the flow rate, or add some obstacles, such as air conditioner fan blades to stir. Although this turbulence can quickly break the hot and cold stratification, the noise may also become louder. Did you know that the "vortex blade" design of the air conditioner outlet is to artificially create turbulence so that the cold air can spread faster?

This HVAC engineer is like a magician, and he has many black technologies for temperature control. For example, in the "wall-adhering effect" sniper battle, when the fluid flows through the pipe, it is like a "wall-licking madman", always flowing close to the wall, and as a result, the edge temperature changes. How to crack it? The air conditioning ducts can be equipped with deflectors, and the floor heating coils adopt S-shaped pipes, which snake like a snake, so that the temperature can be more uniform.

There is also the "power game" of the velocity field. The high-speed fluid is like a "tyrant" that forcibly coerces the surrounding fluids and forms its own temperature "sphere of influence." There are also practical tips here. When working in an office, your workstation should not be facing the air vent. When turning on the air conditioner at home, turn on the "breeze mode" and use up and down sweeping.

When the floor is heated in winter, many people suffer from "hot feet and cold heads", so engineers came up with the ultimate solution - "low-temperature radiant roof". This principle is to allow the ceiling to dissipate heat evenly in the form of radiation, subverting the traditional convection model.

More advanced methods include CFD simulation, which uses computational fluid dynamics software to simulate airflow trajectories, just like playing a game. It can predict temperature dead spots in advance and then accurately design the pipeline layout.

We ordinary people can also become "home temperature management masters", there are a few tricks. When using air conditioners, remember that cold air blows upwards and hot air blows downwards. Use the difference in air density to make the temperature even. If you feel that the wind is too direct, install a windshield to turn the direct air into a "water curtain." When choosing floor heating, remember the secret: choose S-type pipes instead of back-type pipes, the temperature difference can be reduced by 40%; increase the density of bathroom pipes by 20%, and you will not shiver from the cold when taking a shower. In the office, if the work station is under the air outlet, put a basin of water and place a pot of green plants, which can buffer the temperature difference with humidity. If that doesn't work, apply for a small desktop fan to create your own microclimate.

In this future, temperature control is like entering a science fiction world. AI can predict in advance whether you are cold or hot through infrared thermal imaging and human body sensors; the phase-change material wall is like a "temperature sponge" that can automatically absorb and release heat to balance room temperature; there is also a magnetic fluid air conditioner that can use magnetic fields to accurately control the direction of nanofluid, completely eliminating temperature dead spots. How about it? Isn’t it interesting? Is there any "temperature puzzle" in your air conditioner or floor heating?