COMPARATIVE ANALYSIS OF EXERGETIC EFFICIENCY OF HEAT RECOVERY SYSTEMS OF BOILER PLANTS

Abstract

The paper presents the results of a comparative analysis of the exergetic efficiency of heat recovery systems of boiler plants. The need to ensure the efficient operation of heat recovery systems for various purposes determines the importance and relevance of research conducted in this field. The purpose of the work is to increase the exergetic efficiency of heat recovery systems of various purposes. The results of solving the tasks necessary to achieve the set goal are given: - submit heat utilization systems of various purposes in the form of structural diagrams with the identification of exergetic flows of heat carriers; - choose exergetic efficiency evaluation criteria for heat recovery systems of various purposes, calculate their values and conduct a comparative analysis; - develop recommendations for the use of heat recovery systems for various purposes, taking into account the specifics of their application. For research, a complex methodology was used, which combines structural-variant methods of exergetic analysis with methods of presenting exergetic balances in matrix form. Three types of heat recovery systems with different numbers of consumers of recovered heat were considered. Structural diagrams of heat recovery systems of various purposes with identification of exergetic flows of heat carriers between individual discrete elements have been developed. Exergetic losses, thermal exergetic criterion and exergetic efficiency were selected as criteria for evaluating exergetic efficiency. Their values were obtained for heat recovery systems and their elements at different values of the relative power of the boiler. The largest exergy losses occur in the water-heating heat exchanger, smoke extractor and pumping system, the smallest - in the air-heating heat exchanger and gas heater. An increase in the relative power of the boiler leads to an increase in the relative contribution of the exergy losses of the water heating heat recovery system, as well as the pumping system and the pipeline system to the total exergy losses in the heat recovery system. It has been established that increasing the number of consumers of recovered heat in the heat recovery system and using rational ways of reducing total exergy losses increases the efficiency of heat recovery systems. Further developments in this field will allow to increase the exergetic efficiency of heat recovery systems for various purposes.