By letter of 30 June 2016 Eurovent introduced a more detailed rule how to enter volume flows into selection tools in order to comply with EN 308.
We – as Hoval Enventus – clearly state hereby:
There will be no change of technical data in CASER due to this announcement from Eurovent, not now and not after this certification period
All measurements of Hoval Enventus equipment are carried out according to the European Standard EN 308 so that the values calculated by CASER, CARS or EC-calculation always comply with this standard.
It is clear that the mass flow ratio between supply air outlet and exhaust air inlet is used as reference value (see EN 308). As a consequence the nominal volume flow entered in our software is supply air outlet and exhaust air inlet. If these values are equal our customer can rely on balanced mass flow conditions that are the basis for various standards like EN 13053.
Rotors have a leakage. Because the outdoor air mass flow is higher than the supply air mass flow (the ratio is OACF), the mass flow equivalent to supply air mass flow times (OACF -1) will directly go to waste air and is not participating in the energy recovery. Our selection program CASER shows these values if you activate OACF correction, but never has used these values for calculation of thermal performance or pressure drop.
Hoval Aktiengesellschaft and former Enventus AB now Hoval Enventus AB have always used and declared the correct values and therefore are not affected by the Eurovent announcement of 30 June 2016.
The used calculation method is compliant with all relevant standards such as EN 308, EN 13053 and EU directives 1253/2014 and 1254/2014.