Eurovent 18/1: Seasonal efficiency index STER for polyvalent units

This document details a newly proposed seasonal energy efficiency parameter, called STER, for polyvalent units. The STER index takes inspiration from the SCOP and SEER indicators but valorises the energy recovery benefits of simultaneous heating and cooling. Chapter 1 explains what a polyvalent unit is (and what it is not) and how it works and justifies why current assessment methods and regulations are not suitable for such units. Chapter 2 defines the standard climate profiles, operating hours, loads, and temperature regimes that are considered. Finally, Chapter 3 outlines the calculation method and formulas for obtaining the STER index and related parameters.