Leakage characteristics according to VDI 3803 Sheet 5

June 12, 2019
The transfer of partial mass flows from one air flow to the other is referred to as (internal) leakage. It is caused by leaks as a result of a pressure difference (seal leakage) or is function-related, such as the co-rotation of a rotor. This is pointed out in the guideline VDI 3803 sheet 5. At the same time, key figures are defined to indicate the size and type of leakage.
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Pressure Loss

March 22, 2019
The European Regulation EU 1253-2014 limits the energy consumption of ventilation systems with a capacity greater than 250 m³/h for non-residential premises (NRVS). The reference configuration of the bidirectional ventilation system BVS is a casing with two fans, a heat recovery system HRS and one supply air and one exhaust air filter each.
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Crossflow or counterflow?

March 1, 2019
Since the first energy crisis in 1973, heat recovery in HVAC systems has become the benchmark in the industry – even though there was previously no obligation to use it and no mention of minimum thermal efficiency. With the implementation of the Ecodesign Directive...
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