From 2018 to the first half of this year, the air source heat pump cooling and heating market has become the focus of the entire industry enterprises and dealers, in addition to our common floor heating and wind disk refrigeration combined supply system, capillary radiation cooling and heating has also been more and more widely used. What are the advantages of capillary radiation systems? What are the design essentials? What should be paid attention to when designing and installing?

Here are 13 common questions and answers that will give you a comprehensive understanding of capillary radiation systems.

1. Q: Will there be condensation on the cold radiation surface?

Answer: the radiation surface temperature radiation system generally lower than the dew point produces condensation, this scheme has taken reasonable effective dehumidification system, can guarantee the cold radiation surface temperature is always higher than the dew point, dew point temperature in each room at the same time drawbacks are configuration protector, when there is a risk of condensation is detected, the system will automatically shut down, to ensure foolproof.

1) High temperature cold source: the system uses 18℃ high temperature cold water, while ensuring that the capillary network laying sufficient area.

2) Humidity control: The fresh air condensation dehumidification system is used to ensure the appropriate humidity of indoor air, so that the dew point temperature is always lower than the cold radiation surface temperature.

3) Dew point protection thermostat: Each room is equipped with dew point temperature protection system and intelligent room temperature control.

2. Q: Will the capillary network be blocked?

Answer: Under the premise of reasonable design and construction, the capillary network will not be blocked for the following reasons:

1) scaling problem: when the water temperature is greater than 60℃, calcium and magnesium ions in the water will precipitate to form scale. The range of water temperature required by the capillary network system is 18℃ ~ 40℃, and there will be no scaling problem. At the same time, because the inner wall of the capillary network is very smooth, even if there is a slight scale, it will not form obstruction. According to the use of energy-saving building in Tsinghua University for many years, the system does not exist the problem of scaling blockage.

2) Blocking by large particles: The system is equipped with small filter devices to prevent large particles from entering the capillary.

3) The influence of other pipes in the system on the capillary network: For large systems, an independent circulation system is generally used in the design, which is separated from the large system by plate heat exchanger.

4) Corrosion resistance: the system uses corrosion-resistant pipeline and valve parts, PPR material corrosion resistance is very good, can long-term tolerance to acid and alkali solution (PH value 1 ~ 14). The water separator adopts forged brass and nickel plating inside and outside, which can effectively prevent the erosion of copper ions on plastic pipes.

5) Biological slime: In order to prevent the formation of biological slime, after the operation of the system for one year, appropriate pesticide or antifreeze can be added to the system pipeline. For large systems, vacuum degassing machine can also be used for vacuum degassing.

3. Q: Does the capillary decorative layer crack?

Answer: the surface temperature difference range of the installed capillary network is generally within 20℃, which will not cause surface cracking due to thermal expansion and cold contraction, mainly to prevent hollow.

4. Q: How to repair or deal with capillary leakage?

Answer: the stress of the capillary network ring is 1.9mpa, the test temperature is 110℃, and it can keep 8760 hours without failure, no rupture, no leakage. Moreover, the capillary network is prefabricated in the factory, and each piece of the network is tested by 25 kg pressure before leaving the factory.

In the construction process, after the completion of pipeline connection to carry out pressure test. Always keep pressure in the process of finishing construction and hardcover. If there is damage, water leakage will be treated in time to ensure the safety in the process of use. Capillary network is thermoplastic material, dry pipe leakage hot melt repair, such as capillary single pipe leakage, it can be cut off and welded to death, does not affect the operation of the system.

The capillary net is generally installed in combination with the decorative layer, and the leakage point is easy to find and repair. In the process of construction, we should strengthen the protection measures of finished products, and do a good job of reservation and pre-burial to avoid damage as far as possible.

5. Q: What are the design essentials of capillary radiation air conditioning?

Answer: The capillary radiation air conditioning system is a new type of energy-saving comfort air conditioning which can replace the conventional central air conditioning. The system uses water as refrigerant carrier and radiates heating and cooling through uniform and tight capillary network. The system needs only 17~19℃ water supply and return temperature in summer and 32~30℃ water supply and return temperature in winter, which is lower than the energy consumption required by the conventional water air conditioner (7~ 12℃ in summer and 45~40℃ in winter). Therefore, the system saves energy.

Because the capillary radiation air conditioning system carries out radiation heat transfer with uniform radiation surface, the system does not have the convective inhomogeneity caused by conventional convection heat transfer. In addition, the new air replacement system configured for the capillary radiation air conditioning system makes the system more comfortable for conventional air conditioning.

1) Understand the load index of building envelope

First of all, the importance of building structure to capillary radiation air conditioning system should be understood. Since the temperature of the supply and return water at the radiation end of the capillary is only 17 ~ 19℃ in summer, it is obvious that the radiation end of the capillary can only deal with indoor sensible heat (7~12℃ for the supply and return water of conventional air conditioning in summer is the total heat in the room, and condensate water is discharged). The dew point temperature reaching 16.8℃ on the contact surface of the capillary tube wall will generate condensate and affect the water mold in the ceiling area (the capillary water supply temperature rises to more than 20℃ in summer, and the attenuation of refrigeration efficiency doubles).

In the capillary radiation air conditioning system, the indoor latent heat is assumed by the fresh air system (if the building envelope load index is greater than the energy-saving design standard, the air system should also bear the sensible heat that cannot be handled by the capillary). Therefore, the more the building structure is insulated and avoids cold bridge, the more energy saving advantages and the initial investment of capillary and supporting wind system are obvious.

2) Configure the basic new air volume and air supply volume of the house

The new air volume and the air supply volume are two relative concepts about the capillary radiation air conditioning system. The new air volume is generally defined in accordance with the specifications and standards. It can be defined in accordance with the air change times (the air change times of civil houses and public buildings are different according to the functional requirements), or it can be defined in accordance with the per capita new air volume.

The air supply volume is the building load that the wind system bears in order to meet the cooling capacity provided by the capillary tube (the higher the load, the greater the air supply volume; In order to reduce the wind noise, the number of air supply outlets should be increased), it can be seen that the building envelope load index is important to the design and initial investment of capillary radiation air-conditioning system.

3) Determine the capillary laying method

The laying method of capillary is divided into top surface, side wall and ground, and the top surface is the most common laying method at present. Considering to obtain sufficient cooling capacity of capillary, it is recommended to lay capillary cooling on the side wall and ground (the comfort obtained by opening only the ground capillary in winter is higher than the top surface heating).

The top surface capillary laying mode should be adjusted according to the ceiling surface and lamp groove, the utilization rate is limited. The way the capillaries are laid is adjusted according to the owner's investment budget and comfort requirements. If the building envelope index of the building is high, the building energy consumption is large, and the owner is not willing to increase the investment of the ground laying capillary. This can be recommended by adding side wall laying capillaries.

4) Determine the treatment method of fresh air

In an engineering project with high energy consumption, if the whole fresh air is to be realized, the function cannot be realized through the refrigerated dehumidifier + total heat exchanger, so it is necessary to refrigerate the dehumidifier through the runner (but it will increase the unit size and initial investment cost). Therefore, we recommend the use of proportional fresh air treatment, through the freezing dehumidifier + total heat switch + partial return air, calculate the air treatment status point to select the fresh air host.

5) Determine the outdoor freezing source

Because the chilled water temperature of the fresh air main engine is different from the chilled water temperature of the capillary tube, when determining the chilled source, whether it is ground source, water source or air cooled main engine type, if the capillary tube is independently applicable to the cold source, the selected main engine can choose the smaller one according to the correction coefficient of the chilled water temperature. However, if the capillary end and the air system share the cooling source, it is necessary to consider 100% using the capillary * plate change correction coefficient + the cooling capacity of the air system to select the correct cooling source.

6. Q: What is the function of machine room automation? Is it necessary?

Answer: The capillary radiation air conditioning system is a more complex system than the conventional air conditioning system. If the host is operated by the owner, condensation will occur due to misoperation.

For example, if the capillaries run ahead of the wind system, breaking the original wind system protection, prolonged operation can cause the dew point protection system to stop or the top area to become mildewy. Therefore, it is very necessary to control the machine room appropriately.

7. Q: What is replacement fresh air? What does it do?

Answer: Indoor use of lower air supply, air ventilation is called replacement of fresh air. Its function is: supply air temperature is lower than the indoor temperature, spread along the ground to form a new air lake.

The temperature of the human body is much higher than the indoor temperature. The low temperature fresh air floats up under the heating effect of the human body and wraps the human body, so that the human body is always in the fresh air environment, and continues to float up and out through the exhaust outlet. This air flow is a plunger type unidirectional flow, such as smoking and human odor will not affect each other, including formaldehyde and a variety of indoor environmental pollution to the fastest elimination.

Outdoor fresh air dehumidifier also uses replacement mode for energy exchange, summer outdoor high temperature fresh air and indoor discharge of low temperature air for cold capacity exchange, winter outdoor low temperature fresh air and indoor discharge of high temperature air heat exchange, can save more than 65% of the energy in the discharged air.

8. Q: What are the technical requirements for capillary network construction?

Answer: the end material of capillary network air conditioning is hot water PPR, and the connection mode is hot melt connection. For the main of De20*2.0, in special circumstances, it can be connected with quick connection pipe fitting to ensure no water leakage.

When the average ambient temperature is lower than 5℃, considering the cold brittleness of the capillary network, the construction should be stopped if relevant temperature guarantee measures are not taken.

During the construction of capillary network, if it is laid on the wall or roof surface, the general thickness of plaster leveling layer is 0.5cm~1cm; If laid on the ground as ultra-thin heating, the bottom layer needs to be laid with insulation layer, both to prevent reverse heat transfer and leveling, insulation layer is recommended to use foam cement, the general thickness of 2~3cm, capillary network leveling layer thickness of 1cm, no pasty concrete layer in the middle, the total occupied height is 3~4cm.

9. Q: What kind of house is a capillary net system not suitable for?

Answer: The capillary network system is to create a high quality, high comfortable air environment, not only to ensure the temperature, but also to ensure comfortable humidity, is a highly intelligent, integrated system.

In order to ensure the safety and reliability of the whole system, without excessive operation cost consumption, and to achieve an optimal operation and management coefficient, from the perspective of design, there are two types of buildings that are not suitable for capillary network air conditioning system:

The insulation performance of the building maintenance structure can not meet the national energy saving standard of more than 65%;

Chinese restaurants, gyms, bathing rooms and other places with dense flow of people, large amount of activities and heavy evaporation of water vapor.

If the building with capillary network air conditioning contains functional areas such as Chinese restaurant and gym, it can be solved by adding fan coil units.

10. Q: What is the safety and reliability of capillary network air conditioning?

Answer: The raw materials for the end of capillary network air conditioning are thermoplastic green environmental protection materials such as PP-R and PE-RT, which can be hot-melt forming, and have the characteristics of high temperature resistance, high pressure resistance and corrosion resistance. The pressure resistance capacity of the pipeline is inversely proportional to the square of the diameter. Although the wall thickness of the capillary is 0.8mm, it can withstand 19 kg of pressure. The thin wall is only afraid of needles or scratches, so the protection of the finished product is critical.

The end of the capillary network air conditioning has been tested for 8760H, and the water temperature of 110℃ and the pressure of 19 kg did not break or leak for 365 days. This experiment shows that the capillary network can be used normally for more than 50 years.

11. Q: Why does capillary network air conditioning save energy? How much energy?

Answer: the capillary network is an efficient heat dissipation terminal, whether the energy saving and how much energy saving depends on the whole system. High efficiency for the system at the end of effective utilization of low grade energy provides the necessary conditions of housing and urban-rural development organization domestic authoritative expert capillary heat pump air conditioning project for the assessment of scientific and technological achievements, the conclusion is that capillary network combined with heat pump and solar system, can be better than the traditional central air conditioning system energy saving 60 ~ 80%, and specific analysis is as follows:

1) Combined with water/ground source heat pump

After using capillary technique:

Winter heat pump condensing temperature decreased, the original 45℃ water supply to about 30℃, COP increased, energy saving index increased to 50~70%;

Summer capillary network directly using water/ground source heat pump can collector as a natural cold source to eliminate air conditioning indoor sensible heat, in the processing of the total cooling load of 60 ~ 70% or so of the sensible heat energy saving of 80% or more, in addition the capillary network of air conditioning technology, weakened occupies a large proportion in the conventional air conditioning system cooling load gained from the start, peak cooling load, The reduction of the air supply volume of the air conditioner also reduces the energy consumption of the fan by more than 50%, and the comprehensive energy-saving index in summer is 65~75%;

Whether in winter or summer, the capillary network mainly bears the indoor cooling and heating load by radiation. Under the condition of ensuring the same comfort as the convection mode, the indoor heating temperature can be reduced by 2~3℃ in winter, the indoor air conditioning temperature can be increased by 1~2℃ in summer, and the building cooling and heating load can be reduced by 5~10%. Therefore, combined with the application of ground source heat pump and capillary network, the annual energy saving index reaches more than 60%.

2) Combination with solar energy

In the use of solar energy conditions, the use of solar energy in winter to prepare low temperature hot water above 10℃, up to 30℃ when directly supplied to the capillary network system heating, lower than 30℃, by the heat pump host in the solar temperature to continue heating, 30℃ heating hot water, greatly reduce the heat pump energy consumption;

At the same time, the hot water storage tank can be used to store hot water at night. Only in continuous rain and snow weather (no sunlight), completely rely on ground source heat pump heating. About 90% of the heating heat in winter can be provided by the solar energy system with an energy saving rate of about 95%, and the remaining 10% is provided by the heat pump, so the energy saving rate in winter can reach 90~94%.

3) Combined with industrial cooling water/waste heat water/geothermal tail water

If it is used for heat exchange with industrial cooling water/waste hot water/geothermal tail water, the temperature of the system can be directly supplied to the capillary network system for heating when the temperature reaches 30 degrees Celsius. When the temperature is lower than 30 degrees Celsius, the heat pump host can extract energy from the waste water to make 30 degrees Celsius heating hot water, and the residual water after the extraction of energy can be reused. The energy saving effect under heating condition is similar to that under solar condition.

12. Q: Is it possible to open Windows after installing capillary network air conditioning?

Answer: open a window purpose is to make indoor air and outdoor air undertakes exchange, improve indoor air environment thereby. For rooms installed with capillary network air conditioning, the system is generally equipped with replacement fresh air. After being processed by the fresh air unit, the outdoor air becomes dry and clean fresh air, and is sent into the room by replacement. The indoor environment is always kept in a fresh state, and there is no need to open Windows.

If you open a window, you waste energy. In the case of high outdoor humidity, the dew-point protective temperature controller set in the room when the window is opened will automatically close the water to prevent condensation if it is detected that there is a danger of condensation, and the temperature in the room will not reach the designed comfort standard.

13. Q: What should I do if I want to hang a mural on the wall with capillary net?

Answer: the construction of capillary network is generally combined with the decoration. In the construction process, according to the requirements of the owner and the design drawings, the wall positions such as nail holes, sockets and switches are reserved.

After decoration, the wall should not be damaged at will to avoid damage to the capillary. For later changes, thermal imaging can be used to determine the position of the capillary before operation.