Comparison of the performance of PIR ducts with conventional galvanised iron ducts

The air-conditioning system is one of the indispensable supporting facilities of modern buildings, and its power consumption accounts for about 50 per cent of the total power consumption of the building. The air conditioning system consists of the host equipment and the end equipment, and the electrical energy is converted into wind energy by the host equipment, which is transported to each air conditioning area through a huge air duct system. Therefore, when designing an air-conditioning system, it is not only necessary to consider the energy saving of the host equipment, but also more importantly, to choose a ventilation duct system with the best energy-saving effect.

PIR duct is a kind of adiabatic heat preservation and environmental protection light air duct, compared with the traditional galvanised iron duct, it has many advantages such as beautiful, fireproof, light weight, energy saving and environmental protection, anti-mould and anti-bacteria, heat and moisture insulation and sound insulation, quick and easy to install, stable physical properties, high heat preservation, high strength, no formaldehyde, no air leakage, no condensate, corrosion-resistant, free of maintenance, long service life and so on, which is the ideal high-tech product of air conditioning system supporting for the implementation of energy-saving and emission reduction in the modern building. Air conditioning system supporting high-tech products.

I. Performance comparison:

1. Weight

Compared with the traditional galvanised iron duct, the self-weight of the duct is greatly reduced, which not only reduces the labour intensity, but also greatly reduces the load of the building, which is particularly important for high-rise buildings and light steel structure plants. Xi'an hypermarket air-conditioning system, for example, the total area of the duct is 14,000m2, it is calculated that the weight of the duct will reach 188 tonnes if it is insulated with galvanised iron and glass wool, while the weight of the actual general-purpose PIR duct is only 16 tonnes.

2、Silencing function

Traditional galvanised iron ducts must be fitted with silencers and silencing elbows within the air-conditioning system, but the effect is not obvious due to the fact that the duct resonance phenomenon cannot be solved fundamentally. The core material of the duct is PIR foam, and the air duct surface is rolled rustproof aluminium foil, which has an ideal silencing effect, and the whole duct system is a whole-system pipe muffler, which can eliminate not only the machine noise of air-conditioning system, but also the aerodynamic noise, and the average muffling volume can be up to 3dB/m, and the noise of the air outlet is less than or equal to 47dB, so there is no longer the need for additional installation of muffler and muffler elbow in the air duct system.

3、 Thermal insulation and life

Traditional galvanised iron duct insulation material is generally glass wool or rubber material, its thermal conductivity of 0.047-0.052W/mK or so, the effect is poor. Tin bites have air leakage, cold bridge phenomenon on the surface of the duct is serious, resulting in condensation and drip, weathering and corrosion, seriously affecting the service life of the duct. The general service life is 5 to 8 years, and only 3 years in poor environment.

The duct is made of PIR foam with one-time high-pressure forming, the thermal conductivity is 0.018W/mK, and the heat insulation effect is more than 2.5 times that of the traditional galvanised iron with glass wool or rubber plastic heat insulation duct. Due to the scientific 4S system quality control, there is no air leakage or cold bridge in the duct system, and the service life can be more than 22 years.

4. Resistance

PIR duct adopts rolled rust-proof aluminium foil or colour steel or galvanized steel plate as the duct surface, aerodynamic obtuse angle linear circulation type relief design, which has a floating effect on the air and greatly reduces the friction resistance of the transmitted air, and there is almost no dust settling. The wall of traditional galvanised iron duct is the smooth plane of the iron itself, which has an adsorption effect on the air, and the installation of silencer and muffler elbow increases the local resistance by about 15%, so the friction resistance of PIR duct is smaller than that of traditional galvanised iron duct.

5. Fast progress of works

The construction process of traditional galvanised iron ducts is to make the ducts, hang them and then add the secondary insulation, the whole process is time-consuming and labour-intensive, with a long construction period, while PIR is to make the ducts and install them directly, which greatly shortens the progress of the project.

Second, energy-saving insulation duct and traditional galvanised iron duct performance comparison

Comparison of energy savings:

According to the construction of 10,000 square metres of air conditioning air supply system analysis and calculation, assuming that the winter and summer seasons can have the same effect, the average winter and summer 8 months of the year to start the machine, 30 days of operation per month, 10 hours of operation per day, the indoor and outdoor temperature difference of 10 ℃. See the table below for details:

Calculation table of energy saving effect of 10000 square metres of air duct

By Sammi