BELGIUM: Eurovent has released its first ever recommendation on the STER seasonal efficiency index for polyvalent units.
The recommendation, released by Eurovent’s polyvalent units task force (TF-POL), details a newly proposed seasonal energy efficiency parameter for polyvalent units in recovery mode called STER. The recommendation gives details on formulas used for obtaining STER index.
A polyvalent unit is defined as a device capable of providing heating and cooling on two separate and independent water or brine loops using the vapour compression cycle. It has at least two refrigerant circuits, each equipped with three heat exchangers: the cold exchanger connected to the cold loop, the hot exchanger connected to the hot loop and the source exchanger connected to the source, which can be outdoor air or water. The source exchanger is reversible, meaning it can operate both as condenser and evaporator.
The document can be read and downloaded here.