Perhaps many people don't know that heating is a specialized discipline and an industry in its own right. Today, we will popularize some of the basic principles and related knowledge of radiant floor heating, which are the most widely used in heat pump heating.
Water underfloor heating basics
1. What is water floor heating?
Answer: The full name of water floor heating is low-temperature hot water ground radiant heating. It is a way to use hot water not higher than 60 °C as the heat medium, circulate in the heating pipe buried in the ground filling layer, heat the ground, and heat the room mainly by radiation heat transfer through the ground.
2. What is the composition of the water and floor heating system?
Answer: Ground layer, thermal insulation layer, structural layer, geothermal pipes, heat source or hot water transmission pipes, water collectors, control valves, thermostats and electric heating actuators, etc.
3. Is there a national standard for floor heating?
Answer: Yes, in 2004, the Ministry of Construction of the People's Republic of China issued the technical specification JGJ142-2004 for ground radiant heating.
Misunderstandings of floor heating
4. Is the hotter the better?
Answer: Now many people still have a lot of misunderstandings, thinking that the hotter the floor heating, the better, hot to wear underwear at home, but also open the window, in fact, this is not comfortable, nor energy saving, more heat is released by opening the window, the temperature is too high, the temperature difference between indoor and outdoor is too large, and it is easy to catch a cold, it should be said that the more comfortable the better, the floor heating system should be equipped with a control system, like an air conditioner to control the temperature.
5. Will the floor heating pipes leak?
Answer: Each floor heating pipe is laid as a whole, there is no joint in the middle, as long as it is not artificially damaged, it will not leak.
6. Which has a longer service life, floor heating or radiator?
Answer: At present, the service life standard of the new national radiator is 15 years, and the service life standard of floor heating is 50 years.
7. Is it necessary to clean the floor heating pipes?
Answer: perennial water accumulation in the geothermal pipe, the water contains microorganisms, impurities, under certain conditions will produce biological slime, attached to the inner wall of the geothermal pipe, so that the thermal resistance increases, affect the heat transfer, regular pipe cleaning, will make the floor heating more energy-saving, more comfortable.
8. The community is centrally heated, can it be changed to floor heating?
Answer: It is different from floor heating, and it must be agreed by the property and neighbors, because the resistance of floor heating is large, which affects the circulation of the system, and it is easy to lead to the lack of heat in the neighborhood (the heating of separate households is better). But now the radiator in the northern city is changed to floor heating is very much, the hot water of the central heating community should be 60-90 °C, if directly connected to the floor heating system is obviously too high temperature, not only will cause human discomfort due to the high surface, but also reduce the life of the floor heating system. It is recommended to install a floor heating mixed water cooling center, control the water temperature of the floor heating system at 35-50 °C required for floor heating, and install a temperature controller in the room to use the floor heating system.
9. Does the floor heating system also control the temperature like an air conditioner?
Answer: It can be divided into room temperature control, temperature adjustment and opening and closing. If you install a floor heating thermostat, you can set the water temperature, room temperature, and run regularly. It can even be programmed for a week, scheduled for control. It is intelligent and comfortable, and can effectively save energy and control costs.
10. Will the floor heating lose heat downward?
A: The insulation layer of underfloor heating ensures that the heat of the underfloor heating system is mainly radiated upward. The heat that may be transmitted downwards is mainly realized in the way of conduction, the ground must be covered with an insulation layer first, the general thickness should be 2-3 cm, and the heat conducted downward by the floor heating system is very little, which can be ignored.
Underfloor heating installation requirements
11. What problems need to be paid attention to in the operation and management of floor heating?
Answer: During the operation and management of the floor radiant heating system, it is necessary to pay attention to weather changes at all times, especially at the beginning and end of heating, to ensure that the system is not frozen. At the beginning of each heating season, the metal pipe part of the heating pipe should be flushed, and the debris accumulated in the non-heating season should be washed away to prevent the debris from clogging the filter and heating coil. Check the filter regularly and clean it in time to ensure the heating effect.
Filters should be cleaned frequently during initial heating. In view of the creep characteristics of the pipe affected by temperature and pressure, during the heating period, there should be a special person to tighten the manifold and the valves and connectors at the front end many times.
12. What are the restrictions and requirements for the use of floor materials for floor heating systems?
Answer: The floor heating system requires low thermal resistance, low water absorption, and small expansion and deformation of ground decoration materials. Ceramic tile and marble floor materials are especially suitable, followed by solid wood parquet flooring for floor heating.
13. Why is the solid wood floor not suitable for floor heating?
Answer: The thermal resistance of solid wood flooring is large, which will affect the heat dissipation effect. The moisture content of solid wood flooring has certain requirements, and it is easy to be affected by the external environment to produce wet expansion and dry contraction, coupled with thermal expansion and cold contraction caused by heating, it is more likely to produce scooping, twisting, bending, and cracking, which will affect the service life of solid wood flooring. The keel needs to be played during installation, which is easy to break the ring of underground pipes, and the keel is easy to deform and cause the deformation of the solid wood floor.
14. What should be paid attention to when using special floors for floor heating systems?
Answer: Composite solid wood flooring should be thin and narrow in size, with good environmental protection performance and good heat resistance. It is best to use paper mats for floor heating, and ordinary foam mats (aluminum foil foam mats, EPE foam mats, pearl cotton) can not be used.
15. Is the use of wood flooring in the floor heating system safe and environmentally friendly?
Answer: In the international standards, there are very strict requirements for the moisture content, thermal stability and formaldehyde release standards of wood flooring, which meet the requirements of environmental protection. The ground temperature of floor heating is generally less than or equal to 32 degrees Celsius, which is almost no different from the indoor temperature in summer, and does not exceed the range of changes in the normal indoor temperature, does not increase the release of formaldehyde on the floor, and does not have to worry about the deformation caused by water dispersion.
16. What is the general temperature of floor heating supply and return water? What is the temperature difference in the water supply?
Answer: water supply temperature: 60-50 °C return water temperature: 50-40 °C water supply and return water temperature difference should not be greater than 10 °C.
17. Why does the temperature of floor heating water supply not exceed 60 °C?
Answer: If the water supply temperature exceeds 60°C, it will affect the comfort and safety of floor heating, and the service life of the pipe will be shortened.
18. What to do when the water supply temperature exceeds 60°C?
Answer: 1. Manually control the heating system and intelligent temperature control mode to adjust the water supply and return flow; 2. Use mixed water cooling center; 3. Heat exchangers should be used in the central heating community; 4. The family is an independent heat source, and the water mixing tank device should be installed at home. The special boiler for floor heating should close the small damper.
19. Can hot water floor heating be run after construction?
Answer: Hot water ground radiant heating, without commissioning, is strictly forbidden to operate and use. During commissioning, the initial heating should be heated slowly and steadily, the temperature should be 10 °C higher than the ambient temperature, and the temperature should be raised by 3 °C every 24 hours for 48 hours of continuous operation.
20. Is the floor heating system reliable?
Answer: The front floor heating system technology is mature, PE-X, PE-RT and aluminum-plastic composite pipes and other geothermal pipes have good flexibility and happy resistance, low fragile temperature, good chemical corrosion resistance, no rust, not easy to scale, the pipeline and the building have the same life, can be used safely for more than 50 years. The products of regular pipe manufacturers have quality assurance, as long as the construction, inspection and acceptance are carried out according to the specifications, there will be no water leakage and the system is not hot. You can use it with confidence.
21. Can floor heating be metered and controlled by room?
Answer: Floor heating is generally an independent system for each household, and each room can be a loop, so it can fully reflect the residents' self-control over the consumption of hot goods, and also meet the technical requirements of the state of "calculation by household, temperature adjustment in different rooms".
22. Is there a limit to the average temperature of the surface of radiant floor heating?
Answer: Personnel long-term stay area: 24-26 °C, maximum limit: 28 °C; Personnel short-stay area: 28-30°C; Maximum limit: 32°C; No dwelling area: 35-40°C, maximum limit: 42°C; Bathroom & Swimming Pool: 30-33°C, Maximum Limit: 33°C.
23. What is the ground layer, leveling layer, waterproof layer, filling layer, thermal insulation layer, and moisture-proof layer?
Answer: Ground layer: the surface layer of the building ground that directly bears various physical and chemical effects; Screed: A structural layer that is troweld on top of a fill or structural layer; Waterproof layer: waterproof ground water, air permeable structural layer; Filling layer: a structural layer for embedding heating pipes on the base surface of the floor slab to protect the equipment and make the ground temperature uniform); Thermal insulation layer: a structural layer used to block heat transfer and reduce ineffective heat loss; Vapor barrier: A structural layer that prevents moisture from penetrating the ground under the floor of a building foundation or floor.
Underfloor heating accessories are an important part of the system
24. Which pipes can be used as low-temperature ground radiant heating pipes?
Answer: From the performance index of the product, PE-Xa, PE-Xb, PE-Xc, PE-RT, PB, aluminum-plastic pipe and other pipes can meet the requirements of floor heating, from the comprehensive cost performance point of view, PE-Xb, PE-RT pipe is more suitable for the application requirements of the floor heating market. Aluminum-plastic composite pipe comfort has been used in the market for many years to verify the excellent floor heating pipe, high strength, good temperature resistance, bending without rebound, the middle aluminum layer can effectively isolate oxygen penetration, eliminate oxygen corrosion, but the price is very high.
25. What is floor heating and water collector?
A: A water flow distribution and collection device composed of a combination of a water distribution and a water collector. The water divider and water collector are the split and combined parts of each water loop in the floor radiant heating, which has the effect of distributing water flow to each heating area, and it is the connection and conversion place between the metal parts and the plastic pipe, as well as the system exhaust.
26. What are the requirements for the water collector of the floor heating system?
Answer: 1) Each household should be equipped with at least one set of water distribution and water collectors; The branch of the divider and water collector should not be more than 8 roads; 2) The inner diameter of the total inlet and outlet pipes of the divider and water collector is generally DN25mm-DN32mm, and the flow rate of hot coal in the pipe does not exceed 0.8m/s; 3) The inner diameter of the rod of the divider and collector should be greater than the diameter of the total supply and return pipe; 4) The divider and water collector should be higher than the floor heating coil, and the exhaust device should be configured.
27. Can the flow rate of ordinary type dividers and water collectors be regulated?
Answer: This kind of divider and water collector has a simple structure and low price, and most of them use ball valves. It can only open or close the branch loop, and it cannot easily meet the user's precise regulation and control of the flow rate of the branch loop in each functional area. It cannot be connected to automatic temperature control devices such as electric heating valves, and it cannot meet the needs of personalized control of users.
28. How to judge the appearance quality of the heating tube?
Answer: The color of the heating tube should be consistent, the color should be uniform, and there should be no decomposition and discoloration. The inner and outer surfaces of the heating tube should be smooth and clean, and no delamination, pinholes, cracks, bubbles, peeling, marks and inclusions are allowed, but slight, localized, scratches, pits, indents and spots that are not the outer diameter and wall thickness beyond the allowable tolerance are allowed. Minor straightening and turning marks, fine scratches, oxidized color, darkening, water and oil stains can be used as a basis for scrapping.
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