As European legislation* puts pressure on energy users to cut their energy consumption, improve the energy efficiency of buildings and homes, as well as meeting the Commission's 20/20/20 targets, we as an industry need to investigate more appropriate ways to evaluate efficiency.
The Eco-Design Directive (ERP) aims to reduce the environmental impact of products in the EU. With this in mind, an implementing measure for air conditioners is currently being developed to introduce a new method for performance specifications – seasonal efficiency – a measurement that will eventually replace the nominal efficiency method, which has its limitations and is now outdated.
Energy efficiency measurements provide consumers with air conditioning performance ratings. The present method, nominal efficiency, has limitations that result in significant gaps between the rated and actual performance. The new proposed method, seasonal efficiency, will correct this by using a more complex calculation method and is being developed by the EU in ERP (PrEN 14825: inquiry version 2010).
There are major differences between seasonal and nominal calculation:
- The seasonal calculation uses several rating temperatures for cooling and heating instead of just one nominal temperature;
- Seasonal efficiency calculations consider the operation at a partial capacity, instead of the nominal caulation of full capacity; and
- The seasonal efficiency method integrates the power consumed by devices in auxillary mode (when the unit is inactive), which can give you a substantial saving over a period of a year.
Therefore, using the seasonal efficiency calculation method will result in a much more accurate estimation of the real life performance of a product.
*EPB (Energy Performance of Buildings) Directive 2009/91/EC, ERP (Energy Related Products) Eco-Design Directive.