Some calorimeters for the efficiency measurements of power electronic converters were developed in the lab, an example is a 30W-600W calorimeter.

Front and top cross-section view of a calorimeter for loss measurements up to 600W. The dimensions of the inner side of the test room are 704 mm x 420 mm by 312 mm high. The polyurethane insulating foam has 48mm thickness. The thermal resistance is about 1.1K/W.