Aim of research: Analyze and estimate the effectiveness of the use of low-potential heat source by the use of heat pumps in technological schemes of combined power plants with CCGT units. Objects of research: Combined heat and power plant № 5 of Saint Petersburg, Russia in joint work with vapor compression heat pump. In this thesis methodology of thermodynamic analysis and technical-economical calculations of energy equipment were applied. Software package «CoolPack» was applied as well. The work includes introduction, 5 chapters, conclusion, list of used literature.