REAL EXERGY ANALYSIS FOR A HEAT EXCHANGER OF A HEATING SYSTEM

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-07-2 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 42, 489-496 pp, DOI: 10.5593/sgem2017/42/S17.062

ABSTRACT

Exergy analysis is a tool, which indicates how far the system departs from the state of equilibrium. Exergy has been implemented as a preferred means of characterizing the impacts of resource consumption for the purpose of improving decision-making. The present study realizes an energy and exergy analysis for a heat exchanger in operation for a district heating system. Exergy balances of a heat exchanger were therefore established to identify the thermodynamic imperfections of the process using real data. They are determined performance parameters and thermal calculation of the heat exchanger. Performance parameters were also calculated: gross and net thermal efficiency, thermodynamic efficiency and heat retention coefficient. The thermal calculation aimed at determining the temperature logarithmic, the global heat exchange coefficient, the average of primary agent temperature, and the average of secondary agent temperature. In the next step, inlet exergy, outlet exergy (useful exergy) and exergy losses were calculated for a heat exchanger of a district heating system. The results are presented in tabular and graphic form. For the studied process, the exergy efficiency is 49.8%.

Keywords: exergy, heating system, performance parameters, efficiency