1. Control Valves: Specifications, Sizing & Technologies

2. Control Valves: Specifications, Sizing & Technologies
David Kandel
Application Consultant
Belimo

3. Agenda Control Valves: Specification, Sizing and Technologies
Controlling a Coil
Ratings and Definitions
Hydronic Valve Sizing
Steam Valve Sizing
Control Valve Technology
© Belimo, 2012

4. Agenda Control Valves: Specification, Sizing and Technologies
Controlling a Coil
Ratings and Definitions
Hydronic Valve Sizing
Steam Valve Sizing
Control Valve Technology
© Belimo, 2012

5. Understating Coil Behavior
Coil Performance
Resulting Coil Output
Coil Power / Flow ΔT
This is how a new coil is controlled by a properly sized PI valve
The coil curve relates BTUh to flow (blue)
Animation 1: The valve curve relates flow to control signal (orange)
Animation 2: By combining these curves, we can relate BTUh to control signal, shown as he resulting coil output (black)
The following 3 slides illustrate through the affect of degradation on the performance of the coil.
Shown here is the coil as it was manufactured.
Blue line = Coil Output
Orange line =Valve Flow
Green line = Delta T
Valve GPM
BTUh
Flow / Control Signal

6. Agenda Control Valves: Specification, Sizing and Technologies
Controlling a Coil
Ratings and Definitions
Hydronic Valve Sizing
Steam Valve Sizing
Control Valve Technology
© Belimo, 2012

7. Pressure/Temperature Ratings
Valve Specs
Pressure/Temperature Ratings
Body Pressure
Close-Off Pressure
Close-Off Leakage DP
Temp Ratings
Valve Flow
Characterization Curve
Rangeability/Turndown
Valve Authority
Actuation
Fail Safe
Normally Open/Normally Closed

8. Body Pressure Pressure Vessel Burst Rating Measured in psi
Failure Threshold of the Vessel

9. Relationship between Pressure and Temperature
Body Pressure
ANSI Body Rating
Relationship between Pressure and Temperature

10. Close-Off Pressure P1
The maximum pressure that a valve can withstand without leakage while in the fully closed position.

11. Close-Off Pressure Rule of Thumb 2-way Valve
Close-off pressure should at least equal the maximum pressure produced by the circulating pump
3-way Valve
Close-off pressure should at least equal the system differential pressure

12. Close-Off Pressure Close-Off Leakage
Bubble Tight is not an ANSI rating.
Bubble Tight implies No water leakage.

13. Pressure Drop P1 P2
The maximum allowable pressure differential that a fully open valve can withstand without damaging the internals of the valve.

14. Temperature Ratings Media Temperature (hydronic)
Acceptable fluid temperature range
Media Temperature (steam)
Commonly measured in lbs of steam
Ambient Temperature
Usually an actuator rating

15. Characterization Curves
Equal Percentage
Linear
Quick Opening
Modified Equal Percentage ?
Flow
Varies based on design
Butterfly Valves, others
2 Position control
Zone Valves
Modulating Control of a Coil
CCV, PI-Valves, Globe Valve
Modulating Control of Steam Coil or Bypass Applications
ePIV, Globe Valves
Valve Position

16. Rangeability & Turndown
The ratio of maximum flow to minimum controllable flow of a valve body only under laboratory conditions with a constant differential pressure applied across the valve.
Turndown Ratio:
The ratio of maximum usable flow to minimum controllable flow of the valve assembly under installed conditions. It is always lower than the rangeability factor.

17. Agenda Control Valves: Specification, Sizing and Technologies
Controlling a Coil
Ratings and Definitions
Hydronic Valve Sizing
Steam Valve Sizing
Control Valve Technology
© Belimo, 2012

18. Flow Coefficient
FLOW COEFFICIENT (Cv) is the quantity of water in gpm at 60 DegF that flows through an open valve with a pressure drop of 1psi.

19. Hydronic Valve Sizing Example: Coil Requires 8 GPM
Design DP for valve, 4 psi
DP of Valve not to exceed 5 psi

20. Hydronic Valve Sizing Example: Coil Requires 8 GPM
Design DP for valve, 4 psi
DP of Valve not to exceed 5 psi

21. Hydronic Valve Sizing Checking DP Example: Coil Requires 8 GPM
Design DP for valve, 4 psi
DP of Valve not to exceed 5 psi

22. Hydronic Valve Sizing
Checking DP

23. Hydronic Valve Sizing
Checking DP
Which should we select?
And Why?

24. Valve Authority Coil Flow (%) Valve Opening (%) Balance Valve
First animation: Discuss the formula form Valve Authority as it relates to the branch schematic. Walk through an example of a 20 psi drop on the branch, creating A=0.2
2nd animation: Show the distortions that result from A=0.2

25. Valve Authority
Coil
Balance
Valve

26. Valve Authority Distortion
100 90 80
Valve Opening (%)
Flow (%) 70 60
Flow / Coil Output (%) 50 40
0.2 30 1 20
1st animation: Explain how EQ% valve curve acts opposite the coil curve and creates a linear 1:1 heat output (in other words, 20% control signal should result in 20% heat output)
2nd animation: When A=0.2, this starts to fall a part
3rd animation: The nice EQ% curve and the linear output are no longer valid (the equal percent curve will fade to make the graph easier to read, the output line will remain dotted, for comparison.)
4th animation: When we combine the new valve curve with the existing coil curve, we get a new out put that is quite fast acting at low flows.
Note that at 10% valve opening the original output curve puts out 10%, but the new one puts out 20%.
Note that at 20% valve opening the original output curve puts out 20%, but the new one puts out 40%.
At low flows, the space is seeing twice the heat output that the is anticipated by the controller.
5th animation: discuss the over flow and underflow caused by riding up and down the much steeper output curve. 10 10 20 30 40 50 60 70 80 90
100
Valve Opening (%)

27. Should be greater than coil DP Valve Authority > 0.4
Hydronic Valve Sizing
Rules of Thumb
Differential Pressure Across the Valve
Should be greater than coil DP
Valve Authority > 0.4
Typically between 3psi - 5psi for modulating
Typically about 1 psi for on/off

28. Pipe Reduction Factor ½" valve in a ½" pipe with a Cv tested at 10
Same ½" valve in a 1" pipe will test at Cv = 6.3

29. Pipe Reduction Factor

30. Pipe Reduction Factor
Only for Valves with High Cv relative to line size

31. The control valve shall be no less than ½ the pipe size…
Pipe Reduction Factor
Rules of Thumb
Choosing Valves Smaller than Line size
The control valve shall be no less than ½ the pipe size…
However, it’s best to keep the valve size reduction no greater than 2 pipe sizes.
Large pipe reductions can increase the effects of cavitation

32. Piping Considerations
Which is Correct?
And
Why is it Correct?
Template
day month year

33. Agenda Control Valves: Specification, Sizing and Technologies
Controlling a Coil
Ratings and Definitions
Hydronic Valve Sizing
Steam Valve Sizing
Control Valve Technology
© Belimo, 2012

34. ΔP = 80% inlet gauge pressure (psig)
Steam Valve Sizing
Low Pressure Steam (under 15psi)
Cv = Flow Coefficient
Q = lbs per hour of steam
ΔP = Differential Pressure in psig
Po = Outlet Pressure in psia
(psia = psig )
ΔP = 80% inlet gauge pressure (psig)

35. Steam Valve Sizing Low Pressure Steam (under 15psi)
Example: Size a modulating control valve for 160 lb/hr with a 5 psig steam supply.

36. 42% absolute inlet pressure (psia)
Steam Valve Sizing
More than 15psi
Cv = Flow Coefficient
Q = lbs per hour of steam
ΔP = Differential Pressure in psia
Po = Outlet Pressure in psia
(psia = psig )
ΔP =
42% absolute inlet pressure (psia)

37. Steam Valve Sizing More than 15psi
Example: Size modulating 1/3-2/3 valves for a heat exchanger with a design flow of 600 lb/hr at 30 psig.

38. Steam Valve Sizing 1/3rd: 2/3rd: More than 15psi
Example: Size modulating 1/3-2/3 valves for a heat exchanger with a design flow of 600 lb/hr at 30 psig.
1/3rd:
2/3rd:

39. 1/3-2/3 Valve Sequencing

40. Agenda Control Valves: Specification, Sizing and Technologies
Controlling a Coil
Ratings and Definitions
Hydronic Valve Sizing
Steam Valve Sizing
Control Valve Technology
© Belimo, 2012

41. Control Valve Technologies

42. Characterized Control Valves
CCV
Characterized Control Valves
Ball Valve (rotary action)
Characterizing Disc

43. CCV

44. CCV
2-way

45. CCV
3-way (Mixing or Diverting)

46. CCV Pros Cons Applications Valve Summary Inexpensive
Equal Percentage Characteristic
High Close Off
Large Range of Cv
Cons
Hot and Chilled Water with Glycol Only
Applications
Hot & chilled water coils (for air handling units)
Unit ventilators
Fan coils
VAV units

47. Globe Valves
Globe Valves
Linear Action
Plug Design

48. Globe Valves Close-Off Pressure
Close-Off Rating Determined by Force Applied to Stem
Close-Off is Actuator Dependent Pd Pu

49. Globe Valves
3-way Mixing

50. Globe Valves
3-way Mixing

51. Globe Valves
3-way Diverting

52. Globe Valves
3-way Diverting

53. Globe Valves Pros Cons Applications Valve Summary
Equal Percentage or Linear Characteristic
SS Trim works for Steam
Cons
Expensive
Large
2 Versions of 3-way
Close off depends on Actuator
Applications
Hot & chilled water coils (for air handling units)
Chillers

54. Holes in Plate Balance the Pressure
Globe Valves
What is a Pressure Compensated Globe Valve? Pu Pd
Holes in Plate Balance the Pressure

55. Globe Valves Pressure Compensated Close-Off Pressures G665 2½” 51 psi
Standard Globe Valve Close-Off Ratings
AFX24-MFT
2xAFX24-MFT
G665
2½”
51 psi
82 psi
G680 3”
34 psi
56 psi
Pressure Compensated GV Close-Off Ratings
AFX24-MFT
2xAFX24-MFT
G665C
2½”
150 psi
G680C 3”
G6100C 4”
G6125C 5”
G6150C 6”
105 psi

56. Butterfly Valves Butterfly Valves Rotary Action Flow Characteristic:
Modified Equal Percentage
Rotating Disc and Resilient Seat

57. Butterfly Valves

58. Butterfly Valves 3-Way Butterfly Valves 2 Valves linked on a Tee
Mixing or Diverting
1 or 2 Actuators

59. Butterfly Valves 3-Way Butterfly Valves 2 Valves linked on a Tee
Mixing or Diverting
1 or 2 Actuators

60. Butterfly Valves Sizing a BFV: Velocity 12 ft/sec in Standard BFV
32 ft/sec in High Performance BFV

61. Butterfly Valves Pros Cons Applications Valve Summary Up to 30”
Inexpensive
High Close-Off
SS and HP Available
Cons
Modified Eq %
High Cv Relative to Size
Velocity Limitations
Applications
Chiller and Cooling Tower Isolation
Change Over Systems
Large Air Handlers
Bypass Controls

62. V-Ball (Segmented Ball Valve)
V-Ball Valves
For Extreme Conditions
400F Water
250 PSI Steam
150 PSI Close-off
Controls
Equal Percent Flow Characteristic
300:1 Rangeability

63. V-Ball (Segmented Ball Valve)
V-Ball Valves
Rotatory Valve
Single seat
Partial Ball reduced torque requirement

64. V-Ball (Segmented Ball Valve)
Valve Summary
Pros
For extreme applications
High Temp Water
High Pressure Steam
High rangeability
Cons
Expensive
Limited sizes and Cv
Large (heavy)
Applications
Hot & chilled water coils (for air handling units)
Chillers

65. Zone Valves Zone Valves Inexpensive 2 Position Spring Return
“Paddle” Design

66. Zone Valves
2-Way
3-Way Diverting

67. Zone Valves Pros Cons Applications Valve Summary Cheap Fail Safe
2 Position Only
Low Close-Off
Applications
Baseboards
Low Flow needing 2 position, fail safe

68. Pressure Independent Valves
Pressure Independent Control Valves
2-way valve that supplies a specific flow for each value of the control signal –
– Regardless of pressure variations in the system
PI Valve
Pressure
Flow

69. Pressure Independent Technologies Mechanical Regulator
Electronic Flow Meter

70. Pressure Independent Valves
Valve Summary
Pros
Accurate Flow Regardless of Pressure Conditions
Increased Water-side DT
Reduced Pump Energy Usage
Valve Authority = 1.0
Eliminates need of Automatic Balancing Valves
Cons
Higher Initial Cost
Applications
Hot & chilled water coils (for air handling units)
Unit ventilators
Fan coils
VAV units

71. Control Valves: Specifications, Sizing & Technologies
Questions?