Carryover

21 november 2019
The internal leakage of a rotor results from the seal leakage and the carryover. While the leakage depends on the seal quality and the pressure difference, the carryover is due to functional reasons.
Läs mer

Consider the pressure difference!

30 september 2019
There are different pressures on the supply and extract side of a ventilation system – depending on the installed components and the arrangement of the fans.
Läs mer

Concerning the freezing of condensate

30 juli 2019
If humid air is cooled down, the relative humidity rises until condensate is formed. If the outside air is so cold that the extract air is cooled below the freezing point of the condensate, it can freeze and block the heat exchanger on the extract air side partially - or in extreme cases even completely.
Läs mer

Leakage characteristics according to VDI 3803 Sheet 5

12 juni 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.
Läs mer

Pressure Loss

22 mars 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.
Läs mer

Crossflow or counterflow?

1 mars 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...
Läs mer