Abstract <p>The article presents the results of studying of heat transfer during pool boiling of saturated water on a finned surface. The experiment involved certain difficulty in view of lack of primary transducers that would help perform direct measurement of local heat flux. A new model of a heterogeneous gradient heat flux sensor was used, which was installed under the heat transfer surface. By using this sensor, the limit boiling heat flux was determined both on a free finned surface and on a finned surface with a flow restrictor. Modern methods for cooling power electronic devices are briefly reviewed. The choice of devices applied in the study is substantiated. The article presents a description of the experimental facility that makes it possible to study heat transfer during boiling of various coolants near surfaces having different geometrical parameters. A solution according to which the thermocouples are placed under the heat transfer surface for correctly representing the heat flux determination results depending on the change in the temperature of the modeled power module is substantiated. The relative standard temperature and heat flux measurement uncertainties did not exceed 2 and 4%, respectively. The flow restrictor application efficiency was estimated. It has been shown that a flow restrictor installed near the surface helps remove steam–water mixture from the heating surface more intensely, due to which the removed heat flux is increased by 35%. The best effect is obtained from using a flow restrictor on surfaces with a distance between the fins close to twice the capillary distance. In addition, by changing the gap in installing the restrictor, it is possible to adjust natural circulation of liquid and control both the removed heat flux and the power module temperature. The obtained results give grounds to believe that further studies in this area should be carried out.</p>