|The core technology of passive houses|
The passive house was born in Germany. The climate in Germany is similar to that in northern China. It belongs to the cold climate zone. It adopts high-tech energy-saving technologies including high-efficiency external thermal insulation system without heat bridge, double Low-e high-performance thermal insulation external window, and efficient heat recovery. The system, the house is well airtight, make full use of solar energy and other renewable energy, and intelligent control.
(1) High-efficiency external insulation system without heat bridge
The heat transfer coefficient of the roof, exterior wall and basement roof should meet K≤0.15W/(m2.k). The non-transparent outer protective structure needs to be completely covered with thick insulation materials, and there should be no structural thermal bridge formed by beams, plates, columns, etc., and no condensation or mildew may occur. For the inevitable thermal bridge caused by the metal connectors, a blocking thermal bridge facility is required. This construction measure makes the entire outer guard structure play the role of winter insulation and summer heat insulation.
(2) Double Low-e high performance thermal insulation outer window
The outer window has good lighting, heat insulation and thermal insulation properties. The outer window should meet the performance requirements of heat transfer coefficient K ≤ 0.8W / (m2.k), total solar energy transmittance of glass g ≥ 0.35, and glass selectivity coefficient S ≥ 1.25. This performance window allows selective transmission of light of different wavelengths. Thereby, the natural light is used to satisfy the illumination, and the light that causes the cold load is isolated outdoors in the summer, and the near-infrared rays of the irradiated glass are reflected back into the room in the winter. At the same time, the airtightness level should not be lower than 8th, the watertightness level should not be lower than 6th grade, and the wind pressure resistance performance level should not be lower than 9.
(3) Efficient heat recovery fresh air system
Passive rooms are equipped with a heat recovery fresh air system with a ventilation efficiency of ≥ 75%. The fresh air has a filtration rating of not less than G45 and enters the room. The air quality should meet the requirements of CO2 ≤ 1000ppm and can be automatically operated all year round. Such a fresh air system controls energy loss to within 25% each time it is ventilated.
(4) Good air tightness of the house
The house shall have a continuous and complete airtight layer surrounding the entire heating volume; each dwelling unit shall have a continuous and complete airtight layer surrounding the entire heating volume. The airtightness of the house must meet the condition that the indoor and outdoor pressure difference is 50 Pa, and the number of air changes per hour does not exceed 0.6. That is, the requirement of n50=0.6 is satisfied. In order to achieve the specified requirements of airtightness, a series of technical measures are needed to deal with the connection nodes of the external protection structure. Such as the connection between the door and window and the external wall; the sealing treatment of the through-wall pipe; the sealing of the hole of the switch socket is installed.
(5) Make full use of solar energy and other renewable energy sources
Depending on local conditions, the full use of renewable energy can reduce the dependence of buildings on fossil energy and the consumption of primary energy.
(6) Intelligent control
Residents can set indoor temperature and CO2 concentration according to their own preferences. The air conditioner automatically operates according to the indoor CO2 concentration and the indoor temperature. On the one hand, this method ensures the comfort of the room and on the other hand avoids the continuous operation of the new fan and achieves the purpose of energy saving.