Page 219 - Boiler plant and distribution system optimization manual

204 Boiler Plant and Distribution System Optimization Manual

11,700 – 667 economizer were both installed as the same proj-
ROI (%): —————— = —————% ect?
10,000
(Ans.: 110%) As found efficiency 70.3%
Optimized efficiency 86.8%
Option 2. Calculate the ROI for an economizer if Optimized fuel savings (%) 19.0%
the estimated lifetime is 15 years: Optimized fuel savings ($) $19,000/Yr

16,000 – 2000 30,000 + 10,000
Payback Period ——————— = —————
ROI (%): ——————— = ————%
19,000-2,000
30,000
(Ans.: 46.7%)
(Ans.: 2.35 Yr.)

Return 19,000 – 2,667
Part Iv: Economic Analysis, Installing
on = —————— = ————
Oxygen Trim and Economizer
Investment 40,000
Separately and Together
(Ans.: 40%)
Option 3. Assuming the oxygen trim system has
been installed, what are the benefits from install-
ing the economizer under the new operating con-
COST OF MONEY
ditions?
The cost of money may affect energy saving
Efficiency with oxygen
projects. The purpose of this section is to illus-
trim system 79.6%
trate how the longer payback periods are affected
Efficiency with economizer 86.8%
by the cost of money and also how interest rates
Annual fuel savings(%) 8.3%
change the time needed to recoup investments.
Annual fuel savings ($)
Your company must borrow money at vari-
$8,295/Yr
ous interest rates, how long will it take to recoup
the investment required for energy conservation
30,000
Payback Period = —————— = ———— projects with different payback periods and for
8,295- 1,000 various interest rates? (See page ___)

(Ans.: 4.1 Yr.) (1) Find the discount rate column.
(2) Locate simple payback period under the as-
Return 8,295-2,000 sumed interest rate.
on = —————— = ———— (3) The approximate time to recoup investment
Investment 30,000 will be found in the left column under the
“lifetime” heading.
(Ans.: 21%)
(Note. These values are approximate and are giv-
Option 4. What would the payback period and en only to illustrate relative values)
return on investment be if the oxygen trim and