The revolving door of the building that cannot be accessed quickly may seem useless, but it is actually the king of design that saves the building.

When you go to a relatively high-end building, you may encounter a revolving door, and you have to slow down and push the revolving door to enter the room , which gives people a very inefficient feeling.

Perhaps because of this, although these doors are installed in high-end buildings and hotels, few people use them.

One ​​statistic found that when swing doors appear on both sides of a revolving door, less than 30% of people will use the revolving door to enter the building. When asked why, most of those surveyed answered that it was difficult to push the revolving door.

However, even if the current revolving door is designed to be fully automatic and does not require people to push it, it is still not a high-frequency Entry and exit options.

Maybe people are used to swing doors, or maybe the speed of this automatic revolving door is often limited to 15 revolutions per minute. In short, it is not very popular, so many people I think this is a failed design and very tasteless.

Then the question is, what is the significance of the existence of the revolving door? Why do many buildings use such a door?

Caption: Revolving door design patent drawing

The invention of the revolving door

The earliest revolving door was invented in 1881 by German designer H. Bockhacker. The characteristic of his design was that it was \”tightly airtight\”

The revolving door is either three-leaf or four-leaf, and is accompanied by a very long arc. The circumference of the arc is exactly equal to the circumference formed by the angle of the blades.

So no matter how the blade rotates, it can keep the room airtight. Because of this, some people think that the revolving door was originally designed to prevent horses from entering the room. However, this view has been changed. It was treated as a joke

Since it can effectively block outside air from entering the room, it may have been originally designed just to keep the room warm. .

In the beginning, if this kind of door is installed, the swing door will not be installed. However, as we said before, its entry and exit may not be particularly convenient for others. I\’m not used to this kind of door, so it caused a big accident once.

One ​​day in 1942, a Boston familyA fire broke out at a popular nightclub, killing 492 people from smoke inhalation due to a stuck revolving door with no swinging door on the side.

Since 1943, there have been swing doors on both sides of revolving doors, and many areas have passed laws that require swing doors to be installed on the sides of revolving doors.

Caption: Add an arrow to the side door on both sides to encourage revolving doors

​Don’t you think it’s weird? You’d rather add one on both sides Two swing doors, but also refuse to give up the revolving door.

In fact, the reason is very simple. The revolving door is not a decoration or useless at all. The benefits it brings are much greater than the harm it causes.

Unimaginable energy saving and emission reduction

First of all, the first point is that it passed Blocking the loss of indoor air conditioning or heating can effectively reduce the building\’s electricity consumption.

Many people may think this is trivial, but in fact, the power it saves is amazing.

It is now difficult to find relevant research on energy saving of revolving doors, because its energy saving has become a general consensus.

The research I found here is a 2006 MIT project. Although it is a bit old, this is the latest research on energy saving of revolving doors.

The researchers calculated the air loss from the revolving doors in one specific building at their school and compared it to the airflow from traditional swing doors.

The results show that eight times more air can flow into or out of a building through a swing door than through a swing door.

​Although the energy consumed to heat or cool the air entering the building varies with the seasons, the researchers calculated that, Everyone can enter and exit through the revolving door throughout the year. Compared with the 23% of people who use the revolving door (this is the usage rate of the revolving door calculated at that time), it saves 80,000 kilowatt hours of energy, which is 80,000 kilowatt hours of electricity.

In fact, compared with the electricity consumption for heating and cooling of the entire building, these are not much, accounting for about 1.5% of the total electricity consumption, but if we convert it into carbon emissions , which can reduce approximately 14.6 tons of carbon dioxide emissions.

If revolving doors are installed in buildings around the world and people are willing to use them, it can indeed effectively prevent global change. Warm.

Another scholar also calculated through this set of data that compared with swing doors, the energy saved each time a revolving door is pushed is approximately 36.54 watt hours.

​In other words, the energy saved each time the revolving door is opened can power a 60-watt incandescent light bulb for more than half an hour. Well, you can save so much electricity by opening the door once.

The energy saving of revolving doors is actually a modern concept. In the past, it was more about safety. /p>

How safe are revolving doors?

As mentioned before, it was probably designed to prevent horses from entering the house, which shows how safe it is.

But in fact, its closed safety is only one aspect, and the other is that it can relieve the chimney effect pressure in the building.

Caption: Pressure changes in the building

​High-rise buildings will bear huge pressure due to air rushing through the building. Just imagine , you can basically understand the huge air-conditioned wind you feel when you pass by an open-door shopping mall in the summer.

The reason for the formation of this kind of wind is very simple. The indoor temperature is lower, which means that the air density is greater, so the air will flow to places with higher temperatures.

The same thing happens when you switch to heating. As soon as you turn it on, the cold air from outside will be squeezed in.

This kind of pressure may shorten the life of the building, but it will not cause the building to collapse in a short time. However, it will be different when a fire occurs.

Just by looking at the name (chimney effect), you should know that it has something to do with fire. I don’t know how many people have seen the previous kind of stove. If a chimney is provided for the stove, the fire will burn more vigorously.

​This is because when there is a fire, its heat causes the air to rise sharply and Expelled through the chimney, cold outside air is drawn in, providing more oxygen.

The same goes for a building, if there is a fire and the door is left open, it will become a typical stove and chimney, and the fire will spread upward quickly

A revolving door can effectively prevent this from happening because it blocks the flow of air.

​You may think of the Boston nightclub fire incident we mentioned earlier. In fact, it was due to a problem with the design of the revolving door at that time.

Since the turnstile allows multiple people to pass, it can ensure a more efficient exit if it does not get stuck.

However, it is estimated that the manufacturer has also thought that people may be anxious and destroy the revolving door when a fire occurs. It is said that most revolving doors can be \”quickly installed and disassembled\”, so there is no need to worry too much. Stuck.

Caption: Hidden side door

​Finally

Now, in some places, in order to improve the utilization rate of revolving doors, designers are also racking their brains, including changing the flat sides Open the door to hide it (as shown in the picture above).

It is estimated that for energy saving reasons, the swing doors on both sides of the revolving doors in many buildings and hotels are also locked. They are encouraging us to use revolving doors, and maybe we should too Develop the habit of walking through the revolving door. After all, you can save a lot of energy every time you go in and out.