The problem of unspoken rules encountered in floor heating design needs to be solved urgently

The design work that should have been completely completed by the Design Institute has evolved into a cooperative mode of “design and design of the floor heating company” in practice. Because the design institutes and floor heating companies are uneven in capabilities and experience, coupled with the lack of effective supervision, this willingness to cooperate will inevitably leave loopholes in the design of the floor heating project, and thus pose a hidden danger to the floor heating project. .

You design, I have hidden rules in the design process

“The design of the floor heating system is relatively laborious. The design institute is not willing to bother to design. In most cases, the design institute only calculates the key parameters such as the heat load, and the rest is completed by the ground heating company. Finally, it is reviewed by the design institute.” In accordance with relevant regulations, the design of the floor heating system in floor heating projects was designed by the developer and commissioned by a qualified design institute. However, many floor heating companies disclosed that in practice, the main design work of the above floor heating system was completed by the floor heating company. of.

The above-mentioned information disclosed by the floor heating construction company actually reflects the unspoken rules of the “floor heating company design and design institute stamp” that are common in the design link of the floor heating engineering market in China.

The design of the floor heating system in the floor heating project is a complex and systematic project. It usually takes a lot of time to design a floor heating system. According to Yu Hong, general manager of Beijing Sifang Ruixing Floor Heating Engineering Co., the calculation of the heat load of the floor heating system is a very easy task for most designers. However, if the entire floor heating system is designed in a comprehensive way, most designers are too lazy to do it because they are too time-consuming. Yu Hong told reporters: “We recently undertook a floor heating project with an area of ​​130,000 square meters. The design of this floor heating project took a whole month of our time. The design of the floor heating system was a rough sketch issued by the design institute. The plan diagram of our company is to complete the rest of the design work."

Many floor heating companies revealed that the reason why design institutes are “too lazy” in designing floor heating systems is that, apart from being “too troublesome”, there is another reason that they do not have enough knowledge of floor heating systems and do not know how to design them according to local conditions. To warm this heating method is a relatively novel heating method compared to the heating radiator heating, before 2004, the floor heating industry has not been a common industry specification in the application field. Therefore, many designers are unfamiliar with how to design a floor heating system. In 2004, after the former Ministry of Construction promulgated and implemented the "Technical Specification for Ground Radiant Heating" (hereinafter referred to as the "Regulation"), designers had a common standard that they could learn from. However, due to the lack of practical experience, many designers are familiar with how to calculate parameters such as heat load, but how to make the floor heating system better use “energy saving”, “comfort”, and “convenience for control” by designing according to local conditions. Such advantages are often powerless. In practice, drawings designed by many designers are eventually rejected by professional floor heating companies. For the above reasons, many designers simply started to cooperate with the company: The design institute mainly issued some key data such as heat load, and the rest of the design work was mainly completed by the floor heating construction company. Finally, the design institute reviewed and sealed the seals. . In this process, the design institute follows the design fee. Over time, this model of cooperation evolved into a “spontaneous situation” and evolved into the unspoken rules to be followed by related parties in the floor heating engineering market.

A blueprint that should have been completely completed by the Design Institute evolved in practice to be completed by the Design Institute and the Floor Heating Company, which made the cooperation between the Design Institute and the Floor Heating Company particularly important. In practice, cooperation between design institutes and floor heating companies will often form the following types of joint bodies: Class A - Experienced design institute professional floor heating construction companies, Class B - Experienced design institutes Non-professional Floor heating construction companies, category C - inexperienced design institutes specializing in floor heating construction companies, category D - inexperienced design institutes non-professional floor heating construction companies. Obviously, different combinations of results between design institutes and floor heating companies will have different effects on the design plan.

If the design of the floor heating system is completed by the A-type consortium and the C-type consortium, the design scheme can generally ensure the safety of the floor heating system as well as the energy-saving and comfort of the floor heating. Because of some negligence that may occur in the design process of design institutes, professional floor heating companies will optimize the design plan according to local conditions. If the design of the floor heating system is completed by a Class B consortium, as long as the design institute in the consortium can strictly control, in general, the safety and basic comfort of the floor heating can also be ensured, but whether the program can achieve energy saving and A more humane heating effect depends to a large extent on the design and construction level of floor heating companies.

In the cooperation between the design institute and the floor heating companies, the worst case is obviously the formation of a D-type assembly. The schemes designed by design institutes lacking practical experience and non-professional floor heating companies will inevitably leave hidden dangers for the floor heating projects.

In the heating practice, almost all the professional floor heating companies have redesigned the designs issued by the design institutes. Many floor heating companies report that because the design proposals issued by the design institutes are either not operational or obviously unreasonable, they have to redesign most of these plans. In the process, many designers of the design institute once said to the technical personnel of the construction company: “You are more professional, and you will revise it as appropriate. We will accept it on the line.” It is easy to see that, compared with the design of heating radiators, The design of the floor heating system is not sufficiently skilled for many design institutes.

Wang Fenglin, general manager of Xinjiang Hongdi Energy Saving Technology Co., still remembers one thing that happened in the A district of Urumqi in early December 2007. At that time, the outdoor temperature of Urumqi was close to minus 20 degrees Celsius. However, the room temperature of almost all the rooms in the residential area with low-temperature hot water surface radiant heating (abbreviated as “water heating”) did not reach the expected temperature. Relevant parties had organized technical personnel of developers, thermal companies, and floor heating construction companies to conduct on-site analysis and found no reason at one time. Finally, it was discovered that when the design institute designed the heating system for the community, the heating radiators (installed in the corridors) and the water heating system (laid in the rooms) were designed in each building at the same time, but they did not take any balanced hydraulic force. Measures. The direct consequence of such a design is that the hot water in each building of the community is preferentially passed through the heating radiator system rather than the water heating system, and thus the water heating system cannot effectively heat.

Wang Fenglin said that similar examples are too numerous to mention: The "Procedure" clearly stipulates that the lengths of heating pipes of the same pipe diameter connected to the same manifold should be relatively close. In practice, part of the design scheme of the construction company, the length of the two loops with the same diameter connected to the same water distributor is actually a difference of 90 meters; the “Regulations” stipulates that in the ground where the floor heating system is laid, the personnel frequently stay in the area. The maximum temperature can not exceed 28 degrees Celsius, and in practice, according to some of the construction company design program calculations can be found that the maximum temperature of personnel often stay zone reached 38 degrees Celsius! Unfortunately, such plans have actually been successfully accepted by the Design Institute!

For the above-mentioned problems in the floor heating engineering market, Wang Fenglin analyzed that the design of the floor heating project is a systematic project. Thermal load calculation is only one part of this system project. If the design institute only provides this part of the design results to the construction companies, this is a great test for the floor heating companies. If the construction company does not have basic HVAC knowledge and rich practical experience, various problems will be inevitable. Therefore, on the one hand, the relevant national authorities should promote the design specifications for floor heating projects. On the one hand, they should try to improve the cooperation mechanism and supervision mechanism of design institutes and floor heating construction companies, and block the design loopholes in the floor heating engineering market as soon as possible.