1. ME444 ENGINEERING PIPING SYSTEM DESIGN CHAPTER 10 : CONTROL VALVES IN CLOSED LOOP SYSTEMS

2. CONTENT 1.CIRCULATION SYSTEM 2.CONTROL VALVES 3.SELECTION PROCESS

3. 1. CIRCULATION SYSTEM Expansion tank Cooling Tower Air Handling Unit (AHU) Chilled Water Pump Condenser Water Pump Chiller

4. CHILLED WATER/CONDENSER WATER PUMPS

5. CHILLERS/ COOLING TOWERS

6. AIR HANDLING/ FANCOIL UNITS

7. REQUIRED FLOW System Flowrate ( lpm/tonR ) At diff. temp 5.5  C11  C Chilled Water9.0 (2.4GPM)4.5 Condenser Water11.3 (3 GPM)5.7

8. CHILLED WATER CIRCULATION CHILLER

9. PRIMARY/SECONDARY SYSTEM

10. BASIC EQUATION BERNOULLI EQUATION TOTAL PRESSURE = VELOCITY PRESSURE + STATIC PRESSURE ENERGY GRADE LINE = VELOCITY PRESSURE + STATIC PRESSURE + ELV HYRRAULIC GRADE LINE = STATIC PRESSURE + ELEVATION

11. LOSS MAJOR LOSS: PRESSURE DROP IN PIPE MINOR LOSS: PRESSURE DROP IN FITTINGS AND VALVES

12. CLOSED LOOP SYSTEM 1234 UNBALANCED PRESSURE DROP FOR EACH CIRCUIT 20 GPM403035

13. BALANCE THE PRESSURE DROP 1234 BALANCING VALVE, CONTROL VALVE OR REGULATOR

14. REVERSE RETURN DESIGN

15. TWO WAY VS. THREE WAY VALVE variable flow rate constant flow rate

16. 2. CONTROL VALVES SUITABLE DO NOT USE (B) REGULATING, FLOW BALANCING (A) PROCESS CONTROLLING

17. CONTROL VALVE Cv AND Kv Q IN GPM  P IN PSI S.G. = SPECIFIC GRAVITY Kv = 0.86 x Cv Q IN CU.M./HR  P IN BAR S.G. = SPECIFIC GRAVITY

18. VALVE CHARACTERISTIC

19. CONTROL VALVE CONSTRUCTION

20. CONTROL VALVE RANGE

21. 3. SELECTION PROCESS 1234 0.7 BAR PUMP: 29 cu.m./hr @ 2 bars

22. CALCULATING Kv 1234 0.7 BAR

23. VALVE SELECTION

24. VALVE AUTHORITY VALVE AUTHORITY = EXPECT 30%-40% AUTHORITY LARGE PIPES + HIGH HEAD PUMP LEAD TO HIGH AUTHORITY PRESSURE DROP AT VALVE OVERALL PRESSURE DROP