ME 444 ENGINEERING PIPING SYSTEM DESIGN CHAPTER 10

ME 444 ENGINEERING PIPING SYSTEM DESIGN CHAPTER 10 : CONTROL VALVES IN CLOSED LOOP SYSTEMS 1

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

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

CHILLED WATER/CONDENSER WATER PUMPS 4

CHILLERS/ COOLING TOWERS 5

AIR HANDLING/ FANCOIL UNITS 6

EXPANSION TANKS 7

REQUIRED FLOW Flowrate ) lpm/ton. R( System At diff. temp 5. 5 C 11 C Chilled Water (2. 4 GPM). 09 4. 5 Condenser Water 3) 11. 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 20 GPM 1 20 2 20 3 20 4 UNBALANCED PRESSURE DROP FOR EACH CIRCUIT 13

BALANCE THE PRESSURE DROP 1 2 3 4 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. VALVES (A) PROCESS CONTROLLING (B) REGULATING, FLOW BALANCING SUITABLE DO NOT USE 17

VALVE INSTALLATION AT AHU 18

VALVE INSTALLATION AT AHU https: //www. youtube. com/watch? v=QWh_oe. F 8 y 3 w 19

BALANCING VALVE Hydro monometer 20

VALVE Cv AND Kv Q IN GPM DP IN PSI S. G. = SPECIFIC GRAVITY Q IN CU. M. /HR DP IN BAR S. G. = SPECIFIC GRAVITY Kv = 0. 86 x Cv 21

VALVE CHARACTERISTIC 22

CONTROL VALVE CONSTRUCTION 23

CONTROL VALVE RANGE 24

PRESSURE INDEPENDENT CONTROL VALVE (PICV) 25

3. VALVE SELECTION PROCESS Pump capacity: 900 lpm@30 m. WG. 26

Size the Pipes 27

Compute Pressure Drops 28

Valve Selection 29

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