Energy management systems are used to analyze the efficiency of energy
systems and identify any problem areas to lower costs and save energy,
typically using energy based performance measurements. Our aim was to use
exergy parameters, instead, to see if more accurate information could be
obtained about which energy saving application would result in greater
energy savings. Exergy analysis is based on the second law of thermodynamics
and focuses on the environment and the quality of the energy. Implementing
an exergetic approach to analyze a steam heating system, we examined data
related to exergy flows and exergy losses, and ultimately improved the
performance of the system through this energy management model. The
following seven energy saving applications were identified and ranked
according to their improvement potentials: adjusting the air to fuel ratio
(1), preventing steam leaks (2), installing an automatic blow down system
(3), insulating the pipes (4), insulating valves and flanges (5), insulating
fuel tank (6) and recovering heat loss from the waste condensate (7). The
optimum ranking obtained through the exergy analysis was 3-1-2-5-7-6-4. A
reduction of 15.918 kW in exergy consumption was achieved by installing an
automatic blowdown system. This meant a total reduction of 1,779.03 kg/year
in total fuel consumption, $1,458.81/year of cost reduction and the total
cost reduction achieved was $1,829.25/year. Making improvements to the seven
selected areas in the system, 38.4% of the energy loss was recovered while
the recovery in the exergy consumption was 44.5%.