1. J. Brenn, P. Soltic, C. Bach, An Approach for Efficiency Modelling of Natural Gas Driven Heat Pumps using Standardized Test Data from Electrically Driven Heat Pumps, supplementary electronic data to this article.
2. DIN 4702-8, Central heating boiler; determination of the standard efficiency and the standard emissivity, Beuth Verlag, 1990.
3. WPZ Wärmepumpen-Testzentrum Buchs, Prüfresultate Luft/Wasser-Wärmepumpen basierend auf der EN 255 (WPZ Töss und Buchs), 2006, available at http://www.ntb.ch/ies/waermepumpen-testzentrum-wpz.html (in German).
4. WPZ Wärmepumpen-Testzentrum Buchs, Prüfresultate Sole/Wasser- und Wasser/Wasser-Wärmepumpen basierend auf der EN 255 (WPZ Töss und Buchs), 2006, available at http://www.ntb.ch/ies/waermepumpen-testzentrum-wpz.html (in German).
5. Institute for applied ecology, Freiburg, Germany, GEMIS Global Emission Model for Integrated Systems, Version 4.4, available at http://www.gemis.de.