Abstract:
Energy conservation is important for the manufacturing
industry in Thailand, which now shoulders a significant energy
cost in the production. In the long term, it is expected that
energy cost will exert an increasing share in the cost of
industrial production.
This thesis reports the result of a study and analysis of
an auto part manufacturing industry, with the intent of identifying
and evaluating the physical steps which will lead to conservation
in electrical energy. The scope of the investigation includes a
study of the situation of electrical energy use in the distribution
system and in the main equipments.
In the sequel, it was found that the power factor for the
380 V 3 phases distribution system was 0.692 and for the 220 V
3 phases system was 0.711.
The investigation of the machineries with large electrical
energy consumption focusses on the induction furnace and the heat
treatment furnace. The first-law efficiency of the induction
furnace was found to be 27 % and its second-law efficiency was
found to be 19 %. The first-law efficiency of the heat treatment
furnace was found to be 13 %
The suggest energy conservation measures include an
installation of capacitor banks which would raise the systems's
power factor to 0.95 , this yields a rate of return of 25 % per
annum and recovery period of 11 months at 15 % interest annually.
The replacement of the present low-frequency furnace to a high-frequency
furnace will yield a rate of return of 22 % per annum and give a recovery
periodof 2 years and 8 months at 15 % interest annually. A replacement
of the fire-brick for the insulating wall of the heat treatment furnace
by rock wool will yield a rate of return of 144 % per annum and a recovery
period of 2 months at 15 % interest annually.