Before answering this question, we must first understand a question. Why is the floor heating reflex membrane?
The merchant who sells this thing will tell you:
“How good the quality of our reflective membrane, mirror aluminum film, 95%reflectivity, can reflect the heat back to prevent it from being passed downstairs …”
I searched on Baidu, and it was easy to find the picture below. There are many marketing words similar to this picture.
This statement sounds very scientific.
But when I heard this statement for the first time, I almost dropped the glasses. Let me talk about why, this statement surprised me:
Here, try to talk about hot delivery in relaxed language. There are three kinds of heat transfer methods: flow, radiation, and conduction. The following diagram directly describes the differences in these three transmission methods. The flow occurs in the fluid, the conduction occurs in the solid, and the radiation occurs in the medium that is “transparent” for radiation, such as air, vacuum, etc.
So in these three forms, only radiation can be reflected,
For example, when others reflect the sun on your face with a mirror, you can feel calories. A concave reflex mirror can also be used to reflect and focus on sunlight, which can be made into a sun stove to burn water or cook.
If you pay attention to observing the very common infrared heater in the south, commonly known as the little sun. There is often a reflection surface behind the infrared heating pipe to reflect infrared heat radiation.
Therefore, the floor heating is a kind of radiation heating, and then the reflective membrane is opened. The radiation is better under reflection. Wow, it sounds like it makes sense again.
However, in the temperature of the ground, the so -called reflective membrane will be placed between the thermal insulation layer and the cement, and the thermal insulation layer and the cement are closely sticked. Thermal radiation needs to exist in air or vacuum. There is no gap between the cement layer and the so -called reflective membrane. Where can I radiate this kind of heat transfer? Between the two solid surfaces of contact, the method of transmitting heat is only transmitted, without radiation!
Well, since there is no hot reflex, why is this film called “reflective film”? Isn’t this blind? At this time, the merchant began to explain to you again: This film is made of aluminum, aluminum is an excellent thermal conductor. This layer of aluminum layer can evenly distribute the calories of the interval thermal tube to the entire ground. The ground temperature is more uniformly evenly and many more……..
It sounds very reasonable again, again,
You can also have a tall academic name, called “balance film” or “average heat layer”.
Here I have specially found the comparison of the conduction performance of different materials. The conduction performance of aluminum is 218. The concrete uses a marble analogy similar to his performance, which is about 0.9. The heat transfer performance of aluminum is more than 200 times the concrete.
However, no, your layer of aluminum can only have a few microns thick. Even if the heat transfer performance of aluminum is hundreds of times the concrete, you can be too thin. In fact, if this layer of aluminum layer is needed to play horizontal heat transfer and make the horizontal directional heat more uniform, the result of measurement and calculation, the minimum minimum aluminum layer’s thickness is at least 0.05-0.1mm, that is, buy it on Taobao to buy it on Taobao The thickness of the highest quality aluminum foil tape is tens of times hundreds of times more than this micron -level thick aluminum film! The heat transfer performance of this several microns thick aluminum is similar to zero, which is much worse than the concrete in the ground. In fact, everyone can often see the floor heating infrared detection diagram from the circle of friends that these very aluminum -plated “reflective film” ground heating systems are used. Under infrared cameras, there are very clear pipeline trajectories, ground on the ground, ground on the ground, the ground on the ground, the ground, and the ground. The uniformity of temperature has not substantially changed.
Seeing this, since this so -called ground heating reflective membrane on the market has the effect of reflected heat in the ground heating, nor does it have the effect of conducting heat conduction. So what does it have?
To put it, it is still a bit of a effect: when the floor heating preservation layer is real, it may look a bit messy, especially the corners of the edge are not the entire plate. This layer of film is a lot more beautiful. So this film with only a few micron thick aluminum layers is called
More suitable. Or print a little grid on the membrane to facilitate the positioning of the tube when paving the heating tube, so it is called
“Dadic Pipe Pipe Positioner”
Also. Anyway, it is not the case for reflective film!
In the end, you can add some gossip about the so -called “reflective film”. This thing began to engage in the earliest fighting people. At that time, a bunch of stories were also told. I did not expect to fight cattle across the mountain. When I talked about the incident when I smoked at the door of the restaurant with a former colleague of the former Soviet Union, a brother proudly claimed this credit for the fighting nation.
In the traditional Western European market, few people used this film with almost no aluminum layer thickness in the early days, and few people now use it. Only the dry ground heating module is used, and the 0.5-1.2mm aluminum plate will be used as the average thermal layer, which does play a strong role in heat transfer.
The following pictures are compared with a hot -flow simulation calculation (from the website:
): Dry ground heating with 0.5mm aluminum plate and ordinary wet floor heating. The heat distribution in the floor structure is obviously different, and the heating speed of the dry system is faster.
With 0.5mm aluminum plate, the hot layer of thermal floor heating
Ordinary wet ground heating
The temperature distribution at a certain moment with dry floor heating and ordinary wet floor heating process
However, what needs to be emphasized is that if you want to play an average role, the aluminum layer must have a certain thickness. The vacuum coating, a few microns of aluminum film, have no thermal effect. It is better as a layer of silver coatings.
It is estimated that I write this article, and there will be many friends who are unhappy, and there are a lot of scolding me in my back. In fact, I just want to be more true. In many cases, our industry needs a little more real spirit, less like a sale, so that our industry can continue to improve and develop.
Uncle Bird Essay 2021
What is the effect of ground heating reflective membrane?