1. Lecture Objectives: Learn about Pumps and System Curves

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

3. Is this open or closed system ? Cooling towers

4. Relationship between velocity in a pipe and pressure drop Δp ~ v 2 Δp = Constant × v 2 Δp [Pa or ft water ] v [m/s or fpm] larger pipe smaller pipe Required power (P) for the pump P = V × Δp P –power [W], V –volume flow rate [m 3 /s], v – velocity [m/s] Δp – pressure drop [Pa] Δp ~ v 2 (Δp ~ V 2 – when same pipe is used ) P ~ V × V 2 – when same pipe is used P ~ V 3 P 2 /P 1 = (V 2 /V 1 ) 3 For the same pipe When different pipe is used for the same flow rate: For the same flow rate V Reduction of D: D1D1 D 2 = D 1 /2 A 1 V 1 P 1 A 2 =1/2 2 A 1 V 2 =2 2 V 1 P 2 /P 1 = (D 1 /D 2 ) 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

5. Head Loss

6. Fittings

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

8. Pump curves NPSHR = Net Positive Suction Head Required

10. Changing Pump Speed

11. Net Positive Suction Head (cavitation)

12. Curve for Multiple Pumps

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

14. Find a system curve for this plumbing configuration

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

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

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

18. 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%2Fdow nload.php%3Ffile%3Dhegberg.pdf&ei=IvcqU_O1KMuE2AWgloHgDA&usg=AFQjCNF RAMzPnbzDpAluhyk4l8u_SKKTdw

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