improved coil is compared only to the standard coil but the superior coil 



is compared to both the standard coil and the improved coil while the 



lifetime coil is compared to the standard coil and to the superior coilo 



The incremental pay-out or E/C ratio of the next level of expenditure for 



higher performance coil is shown in colums 6 and 8 With a sufficiently 



good pay-out for the improved over the standard coil, there may be a relatively 



poor (or non-existent) pay-out for the superior over the improved coil, 



and the superior coil will still show a relatively good pay-out over the 



standard coilo A case in point is the superior coil for Guam, table 1„ 



In this instance, higher performance than provided by the improved coil, 



cannot be justified under the assumptions made for the tabulated example „ 



(Note the 30 and 180-year pay-outs in column 6 ) However, at Pearl 



Harbor the reverse situation exists „ At that location superior coils 



for both air conditioning and equipment cooling/refrigeration show good 



incremental pay-outs and improved pay-outs relative to the standard coil when 



compared to the improved coilo At Charleston (table 3) there appears to 



be no Navy cost advantage attending the use of any higher performance 



coils, while at El Centro the superior coil should probably be given 



serious consideration, as at Pearl Harbor 



On the basis of energy saving, all coils will satisfy the requirement of 

 CNO guidance that a $1,000 investment result in a saving of at least 20 

 million BTUs set for the FY81 MILCON Program (A single exception is the 

 incremental cost of the lifetime air conditioning coil over the superior 

 coil at Charleston, table 3, where the E/C ratio falls to 18„6o) 



Variations at the four comparison sites from coil to coil and between 

 dollar pay-out and E/C ratios are more understandable when it is remembered 

 that the pay-out calculations over a thirty year time span involve large 

 costs for both power and condenser equipment replacement while the E/C 

 calculations involve power consumption only„ 



39 



