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Hydronic System Plumbing Lecture

Learn about plumbing strategies for hydronic systems, pump selection, valve types, chiller performance impacts, and system balancing. Study primary/secondary pumping, coil strategies, and piping effects on flow rates. Understand pump power calculations and system curves.

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Hydronic System Plumbing Lecture

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  1. Lecture Objectives: • Plumbing • Hydronic distribution systems • Chiller/Boiler – Storage – Building • Pumps Reading assignment: Chilled Water Plant Design Guide (Section 4) http://energydesignresources.com/media/2305/EDR_DesignGuidelines_CoolToolsChilledWater.pdf

  2. Primary/Secondary and Tertiary Pumping (schematics A&B below)

  3. Coil Pumping Strategies Variable speed pumps vs. Single pas Valve vs. Mixing valves vs. Diverting Valves

  4. Impact of Piping Coil How will this affect needed CHW flow? What about the chiller performance?

  5. Plumbing Arrangement in Building’s Hydronic Systems Radiators Fan coil systems Baseboard heaters

  6. What is the difference between these two configuration?

  7. Hydronic Terms • Head loss • Open-loop vs. closed loop • Open System • Closed System h Pump Chiller Cooling coil in AHU Pump

  8. Is this open or closed system ? Cooling towers

  9. Relationship between velocity in a pipe and pressure drop Δp ~ v2 Δp = Constant × v2 Required power (P) for the pump • P = V × ΔpP –power [W], • V –volume flow rate [m3/s], v – velocity [m/s] • Δp – pressure drop [Pa] • Δp ~ v2(Δp ~ V2 – when same pipe is used) • P ~ V × V2 – when same pipe is used • P ~ V3 P2/P1 = (V2/V1)3For the same pipe • When different pipe is used for the same flow rate: • For the same • flow rate V • Reduction of D: D2= D1/2 A2=1/22 A1 V2=22 V1 A1 V1 P1 smaller pipe D1 larger pipe Δp [Pa or ft water] P2/P1 = (D1/D2)4- for the same flow rate or 50% smaller diameter of the pipe for the same flow rate wee have: 4 times larger velocity 16 times larger pressure drop and 16 times lager power for the pump v [m/s or fpm]

  10. Head Loss

  11. Fittings

  12. Pumps • Raise pressure and produce flow • Main type • Centrifugal Example of Turbine pump Base mounted Inline Reading (textbook) Page 3-36 - 3-45

  13. Pump curves • NPSHR = Net Positive Suction Head Required

  14. Changing Pump Speed

  15. Net Positive Suction Head(cavitation)

  16. Curve for Multiple Pumps

  17. System Curves ∆p ∆p A+B A+B B A B A V A B V A B Parallel Serial

  18. Find a system curve for this plumbing configuration

  19. System balancing AHU1 AHU2 HC1 HC2 100 ft 1000 ft 10 gpm 2 gpm 10 ft pump BOILER

  20. Valves • Section 5-14 and 6-15 in the textbook • Types • Butterfly Valves • Ball Valves • Globe Valves Three way valves

  21. Valve Sizing and Flow Coefficient Cv value: in liter/hour or…. in Pa Control Valve Selection For Hydronic Systems reference: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCUQFjAA&url=http%3A%2F%2Fbookstore.ashrae.biz%2Fjournal%2Fdownload.php%3Ffile%3Dhegberg.pdf&ei=IvcqU_O1KMuE2AWgloHgDA&usg=AFQjCNFRAMzPnbzDpAluhyk4l8u_SKKTdw

  22. Control Valve Selection For Hydronic Systems Before DC we tried to do this Valve authority

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