Professor Tao Wenquan, an academician of China Academy of Sciences and School of Energy and Power Engineering of Xi Jiaotong University, clearly pointed out in Heat Transfer that all objects in nature emit thermal radiation into space, and at the same time constantly absorb the thermal radiation of other objects, so that heat can be transferred between objects. It can be seen that thermal radiation is only a way of heat transfer, and sunlight is also transmitted to the earth through thermal radiation, so it will not cause harm to human body.
So, if it is electric floor heating, will it hurt? Yu, an associate professor in the Department of Electrical Engineering in Tsinghua University, said that electric floor heating has not only the energy transmitted by thermal radiation, but also the energy generated by electric field and magnetic field, but this energy has the same impact on human body as pickles and coffee. Because the electric heating used in electric floor heating belongs to low-frequency current, it will not cause harm to human body. What's more, there will be shells, floors or tiles on the cables. With these shields, the magnetic field and electric field of the cable will be further reduced.
Moreover, relevant data show that there is an absolute safe distance for civil power supply. As long as it is more than 50 cm away from the power supply, the radiation value measured by the radiation meter is zero, so as long as it is not directly lying on the floor to sleep, it will not be harmed by radiation. In addition, there is no evidence that the thermal field generated by electric floor heating will have an impact on the body.
Generally speaking, the thermal radiation generated by geothermal water is not harmful radiation as people think in traditional consciousness, it is only a way of heat transfer, so it will not cause any harm to human body. Although there will be some electric and magnetic fields generated by electric geothermal energy, it is a low-frequency power supply and protected by insulating layer, so the radiation generated is even lower than that of electric blanket, so don't worry.
Floor is the key factor of geothermal heating.
Since geothermal energy will not cause radiation damage to human body, why do some people feel uncomfortable in geothermal rooms? Experts said that this has a lot to do with interior decoration materials.
Chen Liping, an associate professor at the School of Urban Construction and Safety Engineering, Nanjing University of Technology, said: "Generally, the floors used by families are mainly composite boards. In the production process, formaldehyde, benzene and other substances will be used to make the floor waterproof and moth-proof. Including the process of painting and assembly, the adhesives used contain certain chemicals. " Chen Liping said: "Even if the floor tile is used instead of the floor, it will inevitably contain a certain amount of radioactive substances, such as radon. Even if there is no floor heating in the newly renovated home, harmful substances such as formaldehyde and radon are slowly volatilized all the time. The difference is that materials with good quality have low toxic substances and little harm to the human body. "
Formaldehyde, benzene, radon, these names must be familiar to everyone, in the news about decoration, we also saw a lot. The main pollution source of indoor decoration, such as formaldehyde, when its concentration slightly exceeds the standard, people will smell bad smell, but if they stay indoors for a long time, they will have discomfort symptoms of nose, mouth, eyes and throat; When you can smell the pungent smell, it means that formaldehyde has exceeded the standard. Staying in this environment for a long time will lead to edema and pneumonia, which will seriously lead to death. Especially children, it is easy to induce leukemia or affect the nervous system.
Chen Liping made an analogy: "Opening a house with a warm floor is equivalent to' forcing' toxic gases out of the room, which accelerates the volatilization of formaldehyde and radon. But after a period of time, there is less toxic gas left in the floor. In this respect, floor heating can also be regarded as accelerating' driving away' toxic gases. " Chen Liping reminded that when choosing home improvement materials, we must pay attention to choosing environmentally-friendly and brand-name products, and don't let inferior materials hurt our health because of greed ... >>
Question 2: What are the advantages and disadvantages of floor heating? Advantages:
① Comfort, sanitation and health care: radiant floor heating is the most comfortable heating method, with uniform indoor surface temperature and gradually decreasing room temperature from bottom to top, giving people a good feeling of warming their feet and cooling their heads; It is not easy to cause polluted air convection and the indoor air is clean; Improve blood circulation and promote metabolism.
② Save space and beautify the living room: cancel the radiator and its branch pipes indoors, increase the use area, facilitate the decoration and home layout, and reduce the sanitary dead angle.
(3) Efficient and energy-saving: the radiation heating mode has higher thermal efficiency than the convection heating mode, and the heat is concentrated at the height that the human body benefits; The heat loss during transmission is small; Low-temperature floor radiant heating can be controlled by layers, households and rooms, and users can adjust it according to the situation, which is effective in saving energy.
(4) Good thermal stability: the ground with warm floor and concrete floor have large thermal storage capacity and good thermal stability. In the case of intermittent heating, the indoor temperature changes slowly.
⑤ Low operating cost: Compared with other heating equipment, it can save energy by about 20%, and can make full use of low-temperature hot water resources or use electricity price policy to reduce operating cost.
⑥ Long service life: In low-temperature floor heating, plastic pipes or heating cables are buried underground, with good stability, no corrosion and no man-made damage, and the service life is synchronous with the building. Compared with convection heating, it saves maintenance and replacement costs.
⑦ Strong adaptability: The equipment is not affected by outdoor temperature, which greatly prolongs the service life of the heating system.
⑧ Reduce floor noise:
In China, 15cm thick circular hole slab or cast-in-place concrete slab is generally used, and its sound insulation effect is very poor. People going upstairs will affect the downstairs. Floor heating is adopted, which increases the insulation layer and furniture. Sound insulation effect is very good.
⑨ Low maintenance cost: The floor heating system is made of corrosion-resistant and rust-free materials, so that the pipeline will not be blocked or changed in flow direction due to rust. After the concrete is backfilled, it has been built into the structural layer of the building. If it is not man-made damage, it does not need maintenance within 50 years and can be ignored.
Disadvantages:
1. The floor height is 80mm, because the floor heating insulation board is 30mm, the pea stone concrete filling layer is 50 mm, and the total * * * thickness is 80mm, which has certain influence on the indoor floor height.
2. The maintainability of floor heating is poor. Because floor heating is a concealed project, it is difficult to maintain, so high-tech environmental protection pipes with pressure resistance, temperature resistance, corrosion resistance and good thermal stability should be selected when decorating. Moreover, it is not convenient for secondary decoration, because the floor heating and heating pipes are laid underground, and it is easy to damage the underground pipes when the ground is renovated. At the same time, we should also pay attention not to set too high a temperature when using, otherwise it will reduce the service life of the pipeline.
3. The use of small spaces such as bathrooms is restricted. Because the heating pipe of floor heating is complicated, the floor heating coil should be waterproof before and after laying, and the laying range of small space is small, so the room temperature is likely to fail to meet the heating standard.
4. After the floor heating system runs for 2-4 years, the floor heating pipeline is prone to scale, which requires professional equipment to clean, otherwise it will directly affect the heating effect.
Question 3: Does the harm of floor heating really exist? Pay attention to installation.
Before installing floor heating, you should first choose your own satisfactory floor heating. Floor heating should be easy to use and of good quality. However, when choosing floor heating, many people easily go into the wrong area. Let's first understand the misunderstanding of the choice of floor heating, so as to avoid being at a loss when choosing, or walking into a minefield when choosing.
Many owners believe that floor heating should keep the floor surface warm and dry while keeping it moist. Actually, it's not. Floor heating is to use heating cables to heat rooms, so it is more suitable to use floor heating in large spaces. It is not recommended to use floor heating below 60 square meters to avoid excessive waste. Some people think that the copper radiator for floor heating is more corrosion-resistant and of better quality. In fact, copper radiators encounter sulfur in the soil, which is often too high and easy to cause corrosion. Therefore, if the copper radiator is used, it needs to be cleaned regularly to avoid sulfur corrosion.
When the floor heating is installed, the installation should be safe and planned. The installation of floor heating is not without layout. On the contrary, the layout of floor heating installation needs to be careful. It is necessary to consider the layout of floor heating according to the use area and insulation effect of the room, design the reasonable direction and spacing of floor heating pipes, provide the most suitable heat dissipation for the room according to the radiation principle, and make accurate calculations to achieve the best effect with the least number of pipes. Therefore, the use of floor heating is not as dense as possible. If the distance between the plates of floor heating is too large, it will cause the indoor temperature to be too high and very hot, which will affect people's health. At the same time, the installation of floor heating does not mean that air conditioning can no longer be installed, because floor heating can only achieve the effect of heating, and when cooling is needed in summer, our air conditioning is still needed to exert its strength. Therefore, air conditioning should be properly installed at home to avoid being caught off guard when it is hot.
After the floor heating is installed, the next work is acceptance, which is simpler than the previous two steps, but more professional. Generally, at the time of acceptance, the surface temperature is not as high as possible. In order to save energy and our health, the surface temperature should not exceed 28 degrees, otherwise it will easily lead to many diseases and force people's blood vessels to dilate, so the temperature of floor heating is limited. Floor heating does not mean that the faster the heating speed, the better. Many owners always think that the faster the heating speed, the better the quality. In fact, the rapid acceleration of floor heating will make the surface and room unbearable and affect the service life of the home.
Floor heating is realized by plastic pipes or heating cables hidden under the floor, so the quality of heat medium transmission materials and insulation materials such as pipes hidden under the floor is the main reason that affects the service life of the floor. Whether the design of floor heating system is reasonable, whether the laying position of floor heating pipes and heating cables and the interval between loops are reasonable, and the construction quality are the main reasons that affect the efficiency of floor heating. In order to sit back and relax, neither can be ignored.
Because floor heating is in the initial and rising stage of the market, home improvement floor heating companies are mixed, with uneven design and construction capabilities and improper selection, which can easily cause great losses to customers. Once the problem is exposed a few years later, there will be endless troubles. Some floor heating companies don't run the market with a long-term vision, but the idea of grasping one at a time, which makes many users suffer greatly. Either the floor heating company disappeared halfway or the heating was not smooth after construction. On the one hand, it is caused by the problems of the floor heating company itself, on the other hand, it also reflects that many users are greedy for cheap at the moment. In order to reduce the cost, some floor heating companies cut corners, choose low-quality and low-priced pipes and accessories, increase the distance between pipes when paving, or use pipes with lower specifications, which leads to the floor heating system failing to achieve the expected effect and burying hidden dangers. Experts in the industry suggest that if you want to enjoy the floor heating without worry, you must choose a professional and regular floor heating company with a certain scale qualification, instead of spending unnecessary "tuition fees" for temporary cheapness.
Question 4: What is the effect of floor heating at home? Will it be harmful to human body? Floor heating is one of the most comfortable household heating methods, which is widely used in northern and central regions. More and more families choose floor heating. What are the advantages of floor heating that can win everyone's favor, and what are the disadvantages that need our attention? Floor heating is divided into electric floor heating and circulation system. This paper only analyzes the advantages and disadvantages of liquid circulation system, so that everyone can have a comprehensive understanding of floor heating.
1. Sanitary, health-care and environmental protection function floor heating conforms to the relationship between supply and demand of human body "warming feet and cooling the top" in traditional Chinese medicine, giving people a good feeling of warming feet and cooling the head, without causing convection of dirty air, and the room is very clean. A thermal environment that meets the requirements of human heat dissipation can improve blood circulation, promote metabolism and inhibit cardiovascular diseases; It is especially suitable for the elderly and children, and has more preventive and therapeutic effects on patients with arthritis and old cold legs. Second, comfortable and healthy, suitable for residential floor radiant heating, heat mainly spreads in the form of radiation, and heat is evenly distributed and transmitted from bottom to top. Indoor warm room is cool, which is suitable for the physiological characteristics of human body and gives people natural comfort. Floor heating is currently recognized as the most comfortable way of family heating. Third, good thermal stability Due to the good thermal stability of the ground floor and concrete floor, in the case of intermittent heating, the indoor temperature changes slowly and feels natural. Fourth, the use fee is lower and it saves fuel. Gas is much more energy efficient than electricity. The heat source equipment of floor heating is gas wall-hung boiler. Coupled with good usage habits, the use fee of floor heating is relatively low. 5. Floor heating which does not occupy the use area is installed under the floor, which does not affect the indoor beauty, does not occupy the indoor space, and is convenient for decoration and furniture layout. 6. Reducing floor noise At present, prefabricated boards or cast-in-place boards are widely used in mezzanine floors in China, and the sound insulation effect is extremely poor. If people go upstairs, it will affect the downstairs. The insulation layer is added to the floor heating, and the sound insulation effect is very good, and the floor heating process is silent. Seven. Each household is equipped with an independent water collector, and each room is equipped with an independent control switch, which can be used to switch on and off each room or adjust the temperature. Advantages of floor heating Eight, the service life is long. The plastic pipe is buried in the concrete on the ground. If no one destroys it, the service life will be more than 50 years, and it will not corrode or scale, which greatly reduces the troubles caused by the radiator running, leaking, dripping and maintenance, and can save maintenance costs. One: On-site assembly, random heating is an on-site assembly project, and manufacturers need to transport heating pipes, water separators, insulation boards, aluminum foils, nails, barbed wire and other large and small materials to the construction site for assembly. Due to the differences in site supervision and workers' quality, the density of pipe spacing and the thickness of insulation board are large, and the site is random. Second, the thermal inertia is strong and the temperature control is lagging behind. After doing warm-up exercises or meals at home, people's body temperature generally rises. At this time, it usually takes four hours to reach the set temperature to reduce the indoor temperature, which leads to the time lag of the required comfortable temperature, and it is difficult to effectively and timely play the role of temperature control. Three: One-step molding is difficult to maintain. Floor heating is a hidden system engineering that is assembled on site, molded once and almost irreparable. Once the heating pipe leaks, it is extremely troublesome to maintain it. No matter how to find the leak, it will destroy the decorative surface. Daewoo said that everything has advantages and disadvantages, and so does floor heating. The key is how we view the advantages and disadvantages of floor heating. Choose a professional E 'ente floor heating company to avoid some unnecessary problems in the installation and use of floor heating. Therefore, when choosing floor heating, we should consider our own family situation. Harmless to human body.
Question 5: Is floor heating harmful to health? Now more and more families choose to use floor heating, one of the reasons is its unique heating method. Adopt bottom-up heating characteristics to keep your feet warm and enjoy a more comfortable heating experience.
Chinese medicine often says that "all diseases are from the foot". Foot is the most abundant part of nerve endings in human body, and it is also the most concentrated area of acupuncture points in human body. Cold feet can lead to the occurrence or deterioration of various diseases: strain or rheumatoid arthritis-cold feet or toes can cause pain in the joints of the body, and may lead to aggravation or incurability. Living in a warm indoor environment for a long time can effectively improve the condition, prevent various joint diseases and avoid leg cramps. Sciatic neuralgia-cold legs and feet can also cause sciatica, and long-term cold legs and feet are the main factors leading to sciatica. Legs and feet are sore and numb-cold legs and feet can also lead to poor blood circulation, which leads to leg pain and numbness.
Floor heating can accelerate blood circulation, keep legs and feet warm, and avoid corresponding symptoms in this part. Kidney-Chinese medicine believes that it will lead to cold and kidney deficiency in the lower limbs, leading to insufficient qi and blood, which will cause a series of symptoms, such as joint pain. Keeping the lower limbs warm will accelerate blood circulation, avoid the invasion of cold, and improve symptoms such as kidney deficiency. Colds and respiratory diseases-cold in the lower limbs will reduce the overall immune system, which will lead to colds and various respiratory diseases. Especially the elderly, children and the infirm. Improving the cold of lower limbs will accelerate the blood circulation of human body. When people are in a healthy state, it will greatly improve the overall immunity and prevent colds and respiratory diseases. Diarrhea or loss of appetite-cold feet can cause diarrhea, and cold hands and feet can lead to long-term recurrent diarrhea or nervous diarrhea.
People living in a warm environment can avoid symptoms such as diarrhea and loss of appetite caused by cold. Families with elderly people at home know that any of the above crimes committed by the elderly in winter may lead to serious consequences. I remind you that it is very important to choose a suitable heating system. If you choose inferior floor heating pipe, it will be toxic when radiating. If you choose the right floor heating pipe, it is not only harmless, but also has many benefits.
Question 6: Is floor heating harmful to human body? The conclusion that low-frequency electromagnetic field is harmful to human body is inconclusive. It is similar to those brick phones used in the early days. It is said to be harmful to human body and affect brain cells. Today, with the popularity of mobile phones, those rich people have to answer dozens of calls a day. At first, it was rumored that electromagnetic radiation was harmful to human body, but the research results showed that there was not enough evidence to support this statement. Whether 50 Hz low-frequency electromagnetic field is harmful to human body has not been clearly concluded. Let's look at those physiotherapists, just using the low-frequency electromagnetic field of 50 to 100 Hz for physical therapy. And the effect of physical therapy is obvious. The safe magnetic field intensity of low frequency electromagnetic field is 100 medium crystal in EU, and 20 medium crystal in some countries. China has not issued relevant standards, but only reference standards or standards under discussion, which have not been formally promulgated. When cement floor tiles are used for electric floor heating, in order to increase the thermal insulation of the floor, the distance between the conductor and the ground is generally about 4 cm. The maximum magnetic field intensity on the ground will not exceed 15 microdrops. This is also scientific data.
Question 7: Is floor heating harmful to human body? Advantages of floor heating:
First, it meets the comfort requirements of human physiological fever: people will feel warmer and more comfortable when they start to heat from their feet;
The second is to save indoor area and space: it can save the space occupied by installing radiator and warm air pipe, and increase the use area by 2% ~ 3%;
Third, it can make the indoor heating temperature uniform: after floor heating, the room temperature is distributed in a gradient from bottom to top, the air convection is weakened, the water loss is reduced, and the shortcomings such as thirst caused by radiator heating are overcome;
Fourth, a wide range of heat sources, such as underground hot water, industrial waste heat, heating pipe network, household heating sources and so on.
5. Saving energy and money: Compared with other heating methods, geothermal radiant heating has a relative rayleigh number Ra. Question 8: Is there radiation in the floor heating? Will it affect the body? Dear, first of all, you need to know what radiation is:
Radiation itself is a neutral word. As long as the temperature of all objects in nature is above zero, they constantly transfer heat in the form of electromagnetic waves and particles. This way of transmitting energy is called radiation. Radiation energy radiates linearly in all directions from a radiation source. The energy released by an object through radiation is called radiant energy, but the radiation of some substances may bring harm.
Radiation is divided into electromagnetic radiation and nuclear radiation. Nuclear radiation hazards, such as gamma rays generated by cobalt -60, cesium-137 and iridium-192 sources; β-ray produced by kr-85 source; Neutron rays generated by 24 1Am-Be source, 24Na-Be source, 124Sb-Be source and electron accelerator with energy exceeding 10M; β and α rays produced by unsealed sources; X-rays produced by various industrial and medical X-ray equipment, etc.
So basically everything is radioactive, but those that can produce harmful radiation to the body are: brain and mobile phone.
Around TV sets, stereos, radio and television transmission towers, various microwave towers, radars, high-voltage power transmission and transformation lines, and living room equipment. Moreover, floor heating is only a tool to provide heat energy and will not produce radiation harmful to the body.
The classification of floor heating mainly includes the following:
Hydronic systems is a heating mode in which hot water with the temperature not higher than 60℃ is used as the heating medium, which circulates in the heating pipeline buried in the underground filling layer, heats the whole floor, and supplies heat to the room through radiation and convection heat transfer on the ground.
Electric floor heating is a kind of heating method which embeds a heating cable with an upper allowable working temperature of 65℃ in the floor, uses the heating cable as a heat source to heat the floor, and uses a thermostat to control the room temperature or floor temperature to realize floor radiation heating. It mainly has the advantages of comfort, energy saving, environmental protection, flexibility and maintenance-free.
Advantage comparison
The circulatory system has no radiation and stable fever, which is suitable for the elderly and children. Floor heating pipes have the same life as buildings; Can provide domestic hot water; After more than 20 years of development, the maintenance technology has matured.
The temperature distribution of electric floor heating room is uniform. Adopt floor heating mode, because the whole floor is evenly radiated by electric floor heating, the indoor temperature difference is extremely small. Moreover, the indoor temperature gradually decreases from bottom to top, and the ground temperature is higher than the temperature of the human respiratory system, giving people a comfortable feeling of warm feet and cool head.
Conducive to creating a healthy indoor environment. When the radiator is used for heating, the outlet water temperature is generally above 7 degrees Celsius, but when the temperature reaches 8 degrees Celsius, a cloud of dust will be generated, which will cover the wall above the radiator with dust. Floor heating can eliminate the convection between dust and turbid air and give people a fresh, warm and healthy environment.
High efficiency and energy saving. Because of the large radiation area of heating, the relatively required water supply temperature is low, only 4 to 5 degrees. But also can overcome a part of heat of that traditional heat piece.
If your home is large, you can consider a circulatory system. Electric floor heating can't provide domestic hot water and has slight radiation. Once there is a bad place, it needs to be replaced.
Question 9: Do the six hazards of floor heating really exist? Not long ago, the article "Six Harms of Floor Heating to Human Body" was madly reprinted on Weibo, WeChat and other online platforms, aiming at geothermal heating, a popular heating method in the market at present, and its content was even more shocking. Directly talking about people's health, it is claimed that floor heating has six major hazards. Coincidentally, negative reports such as "the floor is warm and leaking" and "the floor is not warm" are also widely circulated on the Internet.
In autumn, the heating problem has returned to people's field of vision. The article "Six Harms of Floor Heating to Human Body" has undoubtedly touched many people's nerves. The article writes that geothermal heating radiation is likely to induce leukemia and cancer in children. It is also said that the radiation pollution of geothermal heating will affect the circulatory system and metabolic function of human body. In addition, it will also lead to the decline of male quality, abortion of pregnant women and fetal malformation.
However, the statement in this article was quickly refuted by the media. Some media pointed out that the "six hazards" mentioned in this article were plagiarized from an article about the hazards of electromagnetic radiation many years ago. According to industry analysis, the theory of major hazard sources in the heating industry has spread to innocent "lying guns".
In autumn, the problem of floor heating is once again concerned. Recently, an online article entitled "Six Harms of Floor Heating to Human Body" is quite popular. The article carefully analyzes the hidden dangers of floor heating materials such as floors and tiles. However, according to experts' analysis, this article is actually a manifestation of the deterioration of competition between the two camps of floor heating and radiator in the heating industry.
There must be two camps, one is radiator and the other is floor heating. The rise of floor heating in recent years has brought pressure to traditional heating enterprises, and the possibility of trying to save the market by slandering opponents is not ruled out.
Is floor heating harmful? According to industry experts, temperature can affect formaldehyde volatilization, but it has nothing to do with floor heating itself. It is obviously lack of scientific basis to say that floor heating is harmful. From the point of view of "warmth", the effect of floor heating and side heating (radiators) is the same, and some radiators are often wrapped with artificial plates. If floor heating can lead to excessive formaldehyde, then the efficacy of radiators in this respect is no different.
Floor heating is safe, and the quality of materials is preferred.
Recently, a reporter from Bohai Morning Post visited home stores such as Bohai Rim and Easyhome, and found that many consumers are more cautious when choosing floor heating due to the influence of the theory of floor heating hazards.
A floor heating salesperson said that in order to dispel consumers' concerns, they would introduce in detail the method of distinguishing the quality of floor heating. According to the salesperson, the pipeline is the first choice for floor heating. PERT pipe and PB pipe are the first piping system for floor heating. The invention avoids the corrosion of metal parts in the floor heating system by oxygen, prolongs the service life of the pipeline and the system, and also avoids the normal operation of the system after pipeline scaling.
The damage caused. Secondly, it depends on thermal insulation materials. High-density and high-strength ground insulation materials can not only minimize the downward loss of heat, but also avoid the aging phenomenon of using insulation materials. The extruded insulation board with a thickness greater than 2 cm is preferred as the ground material. If polystyrene foam board is selected, the density should not be less than 30kg/m.. In addition, we should pay attention to some details, such as flame retardant materials for insulation boards and aluminum foil films for insulation boards.
If properly maintained, the service life can reach several decades.
At present, the most commonly used materials for floor heating are floors and tiles. As for who is more suitable for floor heating, the insiders gave a fair judgment-each has its own strengths. The floor has good foot feeling, elasticity, excellent thermal insulation performance, neither cold in summer nor hot in winter; The characteristics of floor tiles are relatively stable and not deformed. When choosing, you should fully combine your living habits and family members. If there are children and old people at home, the floor is more suitable.
Regarding the use and maintenance of floor heating that consumers are concerned about, the insiders said that when using floor heating, in the case of insufficient heating, cooking stoves should be installed or auxiliary heating should be carried out on the wall, and the inlet water temperature cannot be simply increased. The reason is that too high heating temperature will affect the service life of plastic heating pipes, make the cable sheath of electric floor heating aging, and even lead to floor deformation. In terms of maintenance, floor heating is really complicated, and it is necessary to dig the ground or wall for inspection and maintenance. However, under the premise that the quality of underground materials reaches the standard, there is no problem in design and construction, and the inlet temperature does not exceed 60℃, the service life of the water pipe for floor heating will last for decades.