Page 65 - Boiler plant and distribution system optimization manual

50 Boiler Plant and Distribution System Optimization Manual

——————————————————————— For the planner and designer, eliminating
When conditions are not observable or known, life cycle system losses should be a primary con-
the assumption is often made that cern right from the drawing board. For the main-
they are negligible . tenance force, pipe insulation, steam trap testing
and repair, steam leak prevention, and conden-
In steam systems most of the losses sate recovery system maintenance can have a
are not observable. significant impact on operating costs. In the boiler
Unfortunately, the losses are quite plant monitoring the amount of make up water
large and jar from negligible. and the condensate return temperature are im-
——————————————————————— portant indicators of the health of the distribution
system. If the pure hot water is not brought back
In this chapter we have examined infor- to the plant by the condensate recovery system,
mation about various ways steam distribution then the expense of new water, chemical treat-
systems control and ultimately waste energy ment and heating it to operating temperature will
including various energy loss mechanisms and just add to avoidable plant expenses.
their relative costs.

Loss Summary

Distribution System Losses Percent Dollars/yr

Insulation Losses
600 psi (10,000 ft.) 1.90% $82,344
175 psi (4,000 ft) 0.46% $19,763
Condensate Recovery sys (10,000 ft) 0.57% $24,703

Flash Steam Load
600 psi (surface losses) 0.91% $39,522
175 psi (surface losses & 11.14% $481,514
75,000 pph load)

External Steam Leaks 1.94% $84,000
Internal Steam Leaks 0.61% $26,556
Steam Trap Failures 1.43% $61,964
———— —————
18.51% $820,360

What If
(1) All steam piping were bare:
600 psi system surface losses 32.38% $1,399,848
600 psi flash losses 33.32% $1,440,585
175 psi system surface losses 4.57% $197,626
175 psi flash losses 15.75% $680,869
———— —————
86.02% $3,718,928

(2) Condensate Recovery System
A 55 F [13C] drop
in system Temperature 4.76% $242,131

(3) No condensate returns
100% make up @ 62F [17C] 11.43% $581,115