Exergy efficiency of the heat pump technologies for cogeneration purposes

Abstract

A methodology for analysing the exergy efficiency of processes in elements of cogeneration systems using heat pump 
technologies has been proposed, which made it possible to determine the effectiveness of solutions and choose a rational path for 
their practical implementation. The work focuses on increasing the efficiency of using heat pump technologies based on low
potential energy sources, which are typical for power plants, in order to obtain a cogeneration effect. For this purpose, the tools of 
mathematical modelling of processes in the proposed system have been used and promising areas of application of heat pump 
technologies at power plants have been identified to determine the possibility of reliable provision of cogeneration needs of 
consumers. The conditions for rational use of low-potential waste heat from power plants for heat pump technologies, which are 
expedient to use in thermal schemes of power plants, have been substantiated, for which the tools of numerical modelling using the CoolPack application program have been applied. Based on the analysis of the results of numerical modelling, the feasibility of using
heat pump technologies for cogeneration needs has been determined. To determine the efficiency of heat pump technologies for 
cogeneration, the exergy method was used, which made it possible to establish the influence of the main elements of the heat pump installation, which have the greatest impact on energy losses during the utilization of the circulating water of the power plant, and determine the feasibility of its use. The paper substantiates the technical feasibility of using heat pump technologies for cogeneration purposes on the basis of energy-saving technologies and environmental safety. It is substantiated that the use of the proposed systems is a promising direction for Ukraine, which is experiencing a shortage of its own energy resources, because it makes it possible to increase the share of substitution of organic fuel and reduce the volume of heat emissions into the environment. Generalization of the results of using heat pump technologies for power plants based on the exergy method allows for more accurate determination of the energy parameters of the processes occurring in the system.