planning:building_services:ventilation:basics:types_of_ventilation
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planning:building_services:ventilation:basics:types_of_ventilation [2014/09/18 18:19] – external edit 127.0.0.1 | planning:building_services:ventilation:basics:types_of_ventilation [2023/06/06 11:38] – yaling.hsiao@passiv.de | ||
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+ | ====== Types of ventilation ====== | ||
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+ | For occupants, the most important planning aspects are health and comfort. Excellent air quality is especially essential and can only be achieved if " | ||
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+ | ===== Gap " | ||
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+ | Gap ventilation through leaks is not adequate in the heating period at all (see also [[..: | ||
+ | * 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. | ||
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+ | * Apart from that, condensation damage can occur due to the warm air escaping through cracks. | ||
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+ | \\ |{{ : | ||
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+ | |//**Wind and weather fluctuate - so does the air exchange in " | ||
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+ | Without comfort ventilation, | ||
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+ | Accordingly, | ||
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+ | * If ventilation is insufficient, | ||
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+ | * If too much ventilation takes place, the air will become too dry and energy consumption will become excessively high. | ||
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+ | ⇒ One of the reasons for home ventilation is to reduce the air humidity in the home slightly, because a high level of moisture in the air often causes building damage. However, the air should not be too dry either. You can find more information on the page about [[.: | ||
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+ | The right level of air humidity is not the only requirement for an adequate exchange of air. Pollution of indoor air, due for example to the radioactive inert gas Radon, must be reduced to safe levels by adding fresh air. ((A long discussion could ensue here about the " | ||
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+ | \\ There are two other things that have changed: | ||
+ | - Buildings are more airtight; draughts are not acceptable any more. | ||
+ | - There are no stoves any more in the homes. From the ventilation perspective, | ||
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+ | If the window is opened wide for long enough, the stale indoor air will be replaced by fresh outdoor air. When the air replacement is complete, the windows doesn' | ||
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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%. 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). Conclusion: The overall air exchange achieved for this measurement is inadequate, more ventilation is required in order to remove the moisture in the room air. Note 1 : the situation depicted in the graph above is not an isolated case, in fact it is the general rule in lots of existing buildings in Central Europe - and we have heard about this from other Winter cold climates in the world, too. This explains why there is so much damage due to moisture in homes in Germany. Behind a cabinet or a picture, the external wall is even colder, here the relative humidity increases – the same happens in areas with thermal bridging. This problem is not " | ||
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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