Overall thermal efficiency of a lumpy coal fired suitably designed
heating furnace, if operated & maintained properly may be about
__________ percent.
(A) 10-15
(B) 25-30
(C) 45-50
(D) 65-70
heating furnace, if operated & maintained properly may be about
__________ percent.
(A) 10-15
(B) 25-30
(C) 45-50
(D) 65-70