A SIMPLE ANALYSIS OF THE EXERGETIC PERFORMANCE OF THE HOT WATER STORAGE AND THE TANKLESS PRODUCTION SYSTEMS

Carlos Pinho¹

¹ CEFT-FEUP

doi:10.20906/CPS/COB-2015-0113

Resumo

An exergy analysis of a domestic hot water production system compares the irreversibility of the water storage and the tankless production systems. To carry out such analysis some basic assumptions were made: a constant temperature heat source and no heat losses from the system towards the surroundings. Under these circumstances it is shown that if hot water is only required for limited periods of time, the hot water storage system leads to lower exergy losses, being thus the preferred option. It is also demonstrated that the use of the joule effect electricity as the system heat source, be it a water storage one or a tankless one, maximizes the system irreversibility and that the tankless system, with the joule effect electricity heat source, is the worst situation.

Palavras-chave: Thermodynamics; Energy; Exergy