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planning:building_services:ventilation:basics:types_of_ventilation

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planning:building_services:ventilation:basics:types_of_ventilation [2015/09/01 10:13] – [The convenient solution: supply and exhaust air systems with heat recovery] wfeistplanning:building_services:ventilation:basics:types_of_ventilation [2019/02/21 12:53] – cblagojevic
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   * Wind and airflow caused by temperature differences fluctuate too much in Central Europe. In a house which is not leaky enough for sufficient air exchange during periods with small windforces, intolerable draughts are still caused during periods with strong winds (following picture).   * Wind and airflow caused by temperature differences fluctuate too much in Central Europe. In a house which is not leaky enough for sufficient air exchange during periods with small windforces, intolerable draughts are still caused during periods with strong winds (following picture).
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   * New constructions in many countries such as Germany are so airtight that air exchange through leaks in the nevelope is insufficient for good indoor air quality. This also applies for modernised buildings with new windows.     * New constructions in many countries such as Germany are so airtight that air exchange through leaks in the nevelope is insufficient for good indoor air quality. This also applies for modernised buildings with new windows.  
-  * Apart from that, condensation damage can occur due to the warm air escaping through cracks.\\+ 
 +  * Apart from that, condensation damage can occur due to the warm air escaping through cracks.
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 |{{ :picopen:nat_ventilation.png?400 }}| |{{ :picopen:nat_ventilation.png?400 }}|
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 Accordingly, the air quality is usually poor and there is an increased risk of high air humidity.  Because we cannot perceive the indoor air quality ourselves and it is not possible for us to estimate the amount of fresh air actually supplied through open windows,  it is difficult, even for an expert, to achieve "just the right" amount of air exchange. Accordingly, the air quality is usually poor and there is an increased risk of high air humidity.  Because we cannot perceive the indoor air quality ourselves and it is not possible for us to estimate the amount of fresh air actually supplied through open windows,  it is difficult, even for an expert, to achieve "just the right" amount of air exchange.
   * If ventilation is insufficient, the air quality will be poor and there will be a risk of condensation occurring.   * If ventilation is insufficient, the air quality will be poor and there will be a risk of condensation occurring.
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   * If too much ventilation takes place, the air will become too dry and energy consumption will become excessively high.   * If too much ventilation takes place, the air will become too dry and energy consumption will become excessively high.
  
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     * If the window is opened wide for long enough, the stale indoor air will be replaced by fresh outdoor air.     * If the window is opened wide for long enough, the stale indoor air will be replaced by fresh outdoor air.
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     * When the air replacement is complete, the windows doesn't need to be kept open any longer (replacing of fresh air with fresh air?).     * When the air replacement is complete, the windows doesn't need to be kept open any longer (replacing of fresh air with fresh air?).
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     * Window ventilation provides this kind of just one complete air exchange each time it takes place.     * Window ventilation provides this kind of just one complete air exchange each time it takes place.
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     * If this is done twice a day, this means two air replacements in 24 hours or an average air change of 2 / 24 h<sup>-1</sup> which is less than 0.1 h<sup>-1</sup>.     * If this is done twice a day, this means two air replacements in 24 hours or an average air change of 2 / 24 h<sup>-1</sup> which is less than 0.1 h<sup>-1</sup>.
  
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 Moisture is continuously being released into the room, especially at night. Moisture is continuously being released into the room, especially at night.
   * If the air is not replaced, the relative air humidity increases – these periods of increased humidity can be seen clearly.   * If the air is not replaced, the relative air humidity increases – these periods of increased humidity can be seen clearly.
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   * One can also see that each time the window is opened for air exchange, the humidity level drops (valleys). The residents open the windows for airing more than twice a day  - but in spite of that the humidity keeps increasing and for long periods of time it remains above 60%.     * One can also see that each time the window is opened for air exchange, the humidity level drops (valleys). The residents open the windows for airing more than twice a day  - but in spite of that the humidity keeps increasing and for long periods of time it remains above 60%.  
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   * The green curve shows the indoor air humidity near the inner surface of the external wall.  A relative air humidity level of more than 80% is often present here.  These are the conditions which encourage mould growth (area in blue).   * The green curve shows the indoor air humidity near the inner surface of the external wall.  A relative air humidity level of more than 80% is often present here.  These are the conditions which encourage mould growth (area in blue).
  
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 Systematic examination of homes has shown that proper distribution of fresh air in all rooms and safe dehumidification of kitchens and bathrooms is possible through **controlled ventilation**. Systematic examination of homes has shown that proper distribution of fresh air in all rooms and safe dehumidification of kitchens and bathrooms is possible through **controlled ventilation**.
   * In this way the fresh air is directly supplied to the living room, office and bedrooms. These rooms are equipped with at least one supply air inlet.   * In this way the fresh air is directly supplied to the living room, office and bedrooms. These rooms are equipped with at least one supply air inlet.
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   * As in exhaust air systems, the kitchen, bathroom and toilet as well as other areas with high humidity and odours are ventilated directly through the extract air outlets.   * As in exhaust air systems, the kitchen, bathroom and toilet as well as other areas with high humidity and odours are ventilated directly through the extract air outlets.
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   * There is a directed flow throughout the house: the fresh air first enters the main living rooms (see illustration), from here it flows through the transferred air zones (usually corridors) into the humid areas. The humid areas have relatively high air changes so that e.g. towels can dry more quickly.\\   * There is a directed flow throughout the house: the fresh air first enters the main living rooms (see illustration), from here it flows through the transferred air zones (usually corridors) into the humid areas. The humid areas have relatively high air changes so that e.g. towels can dry more quickly.\\
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planning/building_services/ventilation/basics/types_of_ventilation.txt · Last modified: 2023/06/06 11:40 by yaling.hsiao@passiv.de