Collecting & using condensate on site

1. Collecting & using condensate on site Catee presentation– December 18, 2013 Diana D. Glawe, PhD, PE, LEED AP Engineering Science Department

2. Energy estimates for san antonio • Extraction, processing, and distribution of potable water 1,939 KWh per million gallons • Wastewater Treatment 2,232 kWh per million gallons 1 million gallons 4,171 kWh (Source: Barker, Bill. 2010. “Energy Consumption Associated with Water.” Environmental Policy Office City of San Antonio.)

3. Carbon footprint estimates for san antonio • 6.8956 x 10-4 metric tons CO2 producedper kWh * • 4,171 kWh per million gallons potable water 1 million gallons 2.84 metric tons (Source: Environmental Protection Agency, Emissions and Generations Resource Integrated Database. <www.epa.gov/egrid> )

4. Energy water nexus • Saving water saves energy • Saving energy reduces carbon footprint (It works the other way around too…… saving energy saves water)

5. On site water sources • Condensate • Rainwater • Cooling tower blowdown • Reverse osmosis wastewater • Gray water • Etc.

6. Condensate Water that collects on a cool surface because the temperature of the surface is below the point at which moisture in the air forms liquid droplets (i.e. dew point)

7. Air Handling Unit (AHU) • (Source: San Antonio Condensate Collection and Use Manual for Commercial Buildings. Pending publication)

8. How Much Condensate?

9. How Much Condensate? Example: 154,440 sq ft (727 ton) applied engineering and technology building measured condensate with predictions (747,290 gallons/yr) Bryant & Ahmed SAWS AWE • (Source: San Antonio Condensate Collection and Use Manual for Commercial Buildings. Pending publication)

10. Condensate Water Quality? • (Source: EPA WaterSense at Work. EPA 832-F-12-034)

11. Condensate Water Quality - Metals • Condensate is slightly acidic • Metals picked up along the flow path (ppm) • Cooling coils • Drain pan • Drainage pipe • Reservoirs/Tank • Pumps • Fixtures

12. Condensate WATER Quality - Microorganisms • Legionella bacterium is primary concern for condensate use if aerosol is possible • Comingling with other water sources adds microorganism possibilities • No fecal matter expected in condensate alone

13. Condensate applications • Cooling tower • Irrigation • Car washing • Water features • Process water • Toilet flushing

14. Condensate (Alone) Applications • Cooling tower make-up water is BEST application • Low initial cost • Easy implementation • Cool and pure water a plus • Low maintenance Example: Building producing 224,511 gallons per year. Cost to install retrofit system for cooling tower makeup water was $2,272 materials (pipes and pumps) plus $750 labor. SAWS rebate 50%. Incremental investment $1,511. Payback period 16 months. No water treatment beyond that already existing for cooling tower water. No overflow and no storage requirements. Maintain air seal and pump (if applicable). • (Source: San Antonio Condensate Collection and Use Manual for Commercial Buildings. Pending publication)

15. Treatment Train when Commingled • Depends on reclaimed water source(s) • Depends on reclaimed water application • (Source: Adapted from Mechell et. al, Rainwater Harvesting: System Planning. 2010)

16. Effective Design – Drain Line Air Seal • (Source: San Antonio Condensate Collection and Use Manual for Commercial Buildings. Pending publication)

17. Standard P-trap • Isolates air handling unit • Minimizes pipe wet time • Maintenance access point • Trap configurations • Draw-thru trap • Blow-thru trap • Standard traps incur • High maintenance • High failure rate (Source: Brusha, Ronald F. “Condensate Traps for Cooling Coils.” HPAC Engineering, Oct 2001)

18. Alternatives to Standard P-trap Condensate pump in drain pan P-trap with additions Pneumatic air seal* P-trap * Patented by Trent Technologies, Inc. (CostGard) • (Source: San Antonio Condensate Collection and Use Manual for Commercial Buildings. Pending publication)

19. Effective design and operation– Automated monitoring • Drip pan overflow alarm • Condensate meter data collection • Make-up water meter data collection • Water quality sensors in treatment train • Make it difficult for system failures to go unnoticed

20. Operation and Maintenance -Scheduled Maintenance Program • Start with commissioning during installation! • AHU: air filter, cooling coils, drain pan • Drain seal • Piping, pumps, and valves • Storage Tank: overflow and makeup water control • Backflow valve inspection • Water treatment filters, lamps, etc. • Water quality tests

21. Condensate on site use • Reduces city’s energy use • Reduces city’s carbon footprint • Potential quick return on investment for facility • Potential to alleviate drought restrictions on site

22. Questions Diana D. Glawe, PhD, PE, LEED AP Associate Professor Trinity University San Antonio, TX 78209 dglawe@trinity.edu 210-999-7515 ?