When discussing system doors and windows, insiders often refer to the "K" value, which is an important value related to the overall thermal insulation and thermal insulation performance of doors and windows. It represents whether the passive windows in your home are qualified, it is related to the comfort of living environment.
What is the k value?
The K value of doors and windows (that is, the heat insulation coefficient of doors and windows and the current national standard and specification are uniformly called the heat transfer coefficient), which is generally the ability of doors and windows to isolate heat; it refers to the heat transferred per unit area per unit time when the air temperature difference on both sides of the enclosure structure is 1 degree (K,℃) under the condition of stable heat transfer, unit: Watt/(square meter · degree)(W/? · K, where K can be replaced by ℃). It reflects the strength of the heat transfer process.
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classification and Calculation Formula of K value
the K value is graded: the grading index value K starts from ≥5.0, k≥5.0 is Level 1, 5.0> k≥4.0 is Level 2, from level 2 to Level 6, every 0.5 reduction is 1 level, that is, 4.0>K ≥ 3.5 is Level 3, 3.5>K ≥ 3.0 is Level 4, 3.0>K ≥ 2.5 is Level 5, 2.5>K ≥ 2.0 is Level 6, the difference above level 7 decreases step by step, 2.0>K ≥ 1.6 is Level 7, 1.6>K ≥ 1.3 is Level 8, 1.3>K ≥ 1.1 is grade 9, K<1.1 is grade 10.
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thus, the lower the k value, the slower the heat transfer process of doors and windows, the better the heat preservation performance. On the contrary, the higher the k value, the stronger the heat transfer process, and the worse the heat preservation performance.
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schematic diagram of heat loss ratio of main structure of house
K value not only depends on the physical properties of hot and cold fluids and their average flow rates, but also depends on many factors such as the thickness of solid wall and the thermal conductivity of materials, generally, it is determined by specific experiments and calculation according to the heat transfer equation.
The Calculation Formula of k value: k = 1/(1/ai Rw 1/AE), where Rw is the thermal resistance of the door and window glass itself, ai and AE are the heat transfer coefficient of the inner and outer surfaces respectively.
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what are the advantages and effects of K value?
Some studies show that the reduction of heat transfer coefficient (K value) of exterior wall will obviously reduce building energy consumption.
The lower the k value, the better the thermal insulation performance of your doors and windows. Generally speaking, the faster the Heat runs outside in winter or invades into the room in summer, the more electricity your air conditioner consumes, the worse the performance of doors and windows, and the length of heat preservation, poor comfort. On the contrary, the slower the "winter heat runs out of the outdoor speed, or the summer heat invades into the indoor speed", the more energy-saving your air conditioner, the better the performance of doors and windows, the longer the heat preservation period, and the excellent comfort.
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according to the measured data, the more energy-saving and energy-saving system doors and windows with lower k value are. For example, a 100? In the House, the k value of doors and windows is less than 1.1. After the air conditioner is turned on for 2 hours, it will take at least 4 hours for the room temperature to recover from the temperature when it is turned off to the outdoor temperature, that is, "it takes two hours to turn on the air conditioner, you can enjoy a comfortable room temperature of about six hours", which greatly shortens the opening time of electrical appliances, reduces energy consumption, reduces electricity costs, and prolongs the comfortable time of space.
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K value and advantages of Waser passive window system
at present, the 102 IPW passive window system developed and produced by Waser system doors and windows has passed PHI authoritative certification of German Passive House Research Institute, with 10 levels of thermal insulation performance and heat transfer coefficient K<0.8, excellent thermal insulation performance, especially suitable for cold or hot climate areas.
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in recent years, with the improvement of people's awareness of environmental protection and the enhancement of national energy conservation propaganda, more and more people choose low-carbon life and pay attention to low-energy products. Waster system doors and windows take low-carbon buildings as the product research and development standard, greatly reducing energy waste and customizing a comfortable life for you.
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as for the k value of system doors and windows, I will share it with you here. If you want to know more about system doors and windows, you can pay attention to the public number. All you want to know is here ~
