VDI 4661:2014-08

Comparision and evaluation of the energetic quality of equipment, plants, systems and also their technical and economic optimization is made on the basis of energetic characteristics. In most cases, they are relative values some of which are dimensionalized and other non-dimensionalized. In general, further items of information are required in addition to the energetic characteristics until an unambigious assessment can be made. The task of this standard is to define both physical and technical terms, to define a number of typical special characteristics and to provide examples for determination and application of characteristics.