Hilario J. Negrón (787) ext 3223 (787) Measuring Operational Efficiency

Monitoring of systems is an important part of maintaining the systems efficiencies, the monitoring process pinpoints problems in any of the systems and provides alarms to solve the issues and avoid costly operational costs PIAA / PRIEN, September 9, 20092

3

4

5

6

7 Boiler System Pretreatment CurrentPotential Boiler Make up Water Operating CostsOperation Hourly steam production (lbs / hr.)20,000 Total annual steam flow175,200,000 Ann. Feedwater (pounds)194,666,667178,775,510 Total feedwater flow in gallons24,641,35022,629,811 Annual condensate - (Gallons)7,392,405 Make up volume (gallons to boiler)17,248,94515,237,406 Total make up gallons (to pretreatment)6,411,39620,316,542 Blowdown rate10.0%2.0% Ann. Blowdown (pounds)19,466,6673,575,510 Blowdown volume (gallons)2,464,135452,596 Blowdown enthalpy (mm BTU's)4, M.U. water charge rate ($/ooo gals.)$2.00 M.U. water cost$34,498$30,475 Sewer discharge rate ($/ooo gals)$2.50 B.D. sewered water cost$6,160$1,131 Plant energy value ($ / mm BTU's)$20.37 Blowdown energy cost$88,409$16,238 Boiler chemical cost$35,000$18,500 Total operating cost$164,067$66,345 Savings comparison with current cost$97,722

 Automatic Blowdown Controls  VFD Boiler Operation  Economizer  Pressure reduction

PIAA / PRIEN, September 9, – 0.7 Excellent Good >.85 Needs Improvement

10PIAA / PRIEN, September 9, 2009

11

Advantages of Primary Secondary Variable Flow System  Very reliable system  System has been proven for many years  Primary system is completely disconnected from secondary  Control system is more simple than variable primary flow  Does not have to monitor flow through chiller Disadvantages  System requires more pumps to operate  Energy consumption is greater than primary flow system  By system will provide water mixture at part loads that will cause supply / return temperatures to vary from design  By-pass system requires more floor space than VPF PIAA / PRIEN, September 9,

Advantages of Variable Primary Flow  Lower first costs  Less equipment to install in mechanical room  Less power required for equipment  Less plant space required since there is less equipment  Reduced pump energy  Higher efficiency pumps  Reduced pressure drops due to fewer pump connections, valves piping etc.  Supply water quantities and temperatures are always maintained at design parameters PIAA / PRIEN, September 9,

Variable primary Flow Design issues  Evaporator flows  Design to maintain minimum water velocity in chiller evaporator tubes at low flow conditions ▪ Before 3 fps was minimum, now 1.5 fps can be achieved  Flow fluctuations in system can affect chillers  Controls  Control systems for VPF systems are more complex than primary secondary ▪ Flow fluctuations ▪ No flow conditions ▪ Bypass valve failure PIAA / PRIEN, September 9,

 Cooling tower cycles  Soft water makeup to cooling towers  System recommissioning balance  Temperature set point