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© Belimo University 2011, All Rights Reserved

Enhancing Sustainability Advantages of pressure independent control valves; basic commissioning of Belimo PI valves. © Belimo University 2011, All Rights Reserved. Enhancing Sustainability. First, an analogy between air systems and hydronic systems. .

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© Belimo University 2011, All Rights Reserved

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  1. Enhancing Sustainability Advantages of pressure independent control valves; basic commissioning of Belimo PI valves. © Belimo University 2011, All Rights Reserved

  2. Enhancing Sustainability First, an analogy between air systems and hydronic systems. Why are there no more VAV pressure dependent air systems?

  3. Air Handling Unit Supply Duct Return Duct Bypass Duct Balancing Damper VVT Boxes Space Temp Enhancing Sustainability Pressure Dependent VVT System How many Pressure Dependent VVT systems have you seen lately?

  4. Air Handling Unit Supply Duct Return Duct Bypass Duct Balancing Damper VVT Boxes Space Temp Enhancing Sustainability Pressure Dependent VVT System • Part Load Performance: • Unable to respond to flow variation due to changing pressure conditions. • Unstable control – system is “oversized”. • Occupant comfort and energy efficiency are compromised. • Spaces too cold (or hot).

  5. Controller From Temp. Control Water Flow Measurement Device Water Flow Enhancing Sustainability Pressure Independent VAV Box Air Flow Temp. Control Controller Air Flow Measurement Device • Part Load Performance: • Flow is controlled under all pressure conditions. Pressure Independent Control Valve • Stable control – system is “rightsized”. • Occupant comfort and energy efficiency are improved. • Spaces at or near design.

  6. Pressure Independent Control Valve What is a pressure independent control valve? A PI Control Valve…. Is a 2-way control valve that supplies a precise flow at any given control signal… Regardless of pressure variations in a system. It is not just a control valve and flow limiting circuit setter in the same assembly! Note: Automatic or manual balance valves should NOT be used with PI valves. If they are already installed they should be set WIDE OPEN.

  7. Pressure Dependent Control Valve Flow rate through equal % globe valve as a function of differential pressure (Cv = 1.9).

  8. Pressure Independent Control Valve Flow rate through PI Control Valve as a function of differential pressure (3 GPM valve plotted). Equal % characteristic.

  9. Equal % Valve Characteristic 100 90 Energy Characteristic of Coil 80 70 60 Coil Energy Output (%) 50 Flow Characteristic of Equal % Control Valve 40 Resulting Energy Output of Coil 30 20 10 10 20 50 90 0 40 60 80 100 30 70 Signal (%) ASHRAE 2008 HVAC Systems and Equipment Handbook pg. 46.8

  10. SAT Setpoint Change PICCV Valve Water Flow Advantages • Iowa Energy Center Pressure Independent Valves Study • Chilled Water Closed Loop Test Globe Valve Water Flow The Pressure Dependent Valve loses authority at part load. In effect, it becomes “Oversized”

  11. Advantages Energy saving potential Globe Valve PI Control Valve

  12. Advantages Energy saving potential Totalized Flow over 24 Hrs Globe Valve = 358.7 gallons PI Control Valve = 283.6 gallons Note: The over-flow and under-flow cycling of this control valve results in a net over-flow condition!

  13. Globe Valve PI Control Valve Advantages Energy saving potential Pump Affinity Laws HP = Horse Power GPM = Flow in Gallons/Minute Globe = 358.7 gallons PI Control Valve = 283.6 gallons A 26.5% increase in flow results in twice the horsepower requirements from the pump.

  14. Pressure Differential Sensor Setpoint = 10 psid Pressure Dependent Control Valves Design: 400 Ton / 800 GPM CHW System @ 12˚ΔT Coil #40 - 200 gpm 10ft H2O (4 psid) 10 psid 4 psid 2 psid Coil #30 - 200 gpm 10ft H2O (4 psid) 20 psid 4 psid 12 psid Coil #2 0 - 200 gpm 10ft H2O (4 psid) 30 psid 4 psid 22 psid Coil #10 - 200 gpm 10ft H2O (4 psid) 40 psid 4 psid 32 psid Chiller 200 tons VFD-Pump Chiller 200 tons VFD-Pump

  15. Advantages Energy saving potential For a given load, flow and ΔTare inversely proportionate.As flow increases, ΔT drops.

  16. Pressure Differential Sensor Pressure Dependent Control Valves Design: 400 Ton CHW System @ 12˚ΔT Coil #40 - 200 gpm Coil #3 0 - 200 gpm Coil #2 0 - 200 gpm Coil #1 0 - 200 gpm Chiller 200 tons VFD-Pump Chiller 200 tons VFD-Pump

  17. Advantages Pressure Dependent Control Valves 180 Ton Load (45%) Design: 400 Ton CHW System @ 12˚ΔT Coil #40 - 200 gpm • Hold the load constant and vary the flow. Coil #3 0 - 200 gpm Coil #2 0 - 200 gpm Coil #1 0 - 200 gpm (12˚ΔT) 54˚ 42˚ CHWR CHWS 360 GPM Loop Flow

  18. Advantages Design: 400 Ton CHW System @ 12˚ΔT Pressure Dependent Control Valves 180 Ton Load (45%) Coil #40 - 200 gpm Coil #3 0 - 200 gpm Coil #2 0 - 200 gpm Coil #1 0 - 200 gpm (10.9˚ΔT) 52.9˚ 42˚ CHWR CHWS 396 GPM Loop Flow (+10%)

  19. Advantages Design: 400 Ton CHW System @ 12˚ΔT Pressure Dependent Control Valves 180 Ton Load (45%) Coil #40 - 200 gpm • An increase in flow results in: • Lower return temperature. • Reduced ΔT. • Increased pumping power. Coil #3 0 - 200 gpm Coil #2 0 - 200 gpm Coil #1 0 - 200 gpm (10.4˚ΔT) 52.4˚ 42˚ CHWR CHWS 414 GPM Loop Flow (+15%)

  20. Pressure Differential Sensor Design: 400 Ton CHW System @ 12˚ΔT Pressure Dependent Control Valves Coil #40 - 200 gpm Coil #3 0 - 200 gpm Coil #2 0 - 200 gpm Coil #1 0 - 200 gpm With a 15% overflow ΔT Reduction goes From 12°F (Design) To 10.4°F (Actual) A reduction of 13%. With a 10% overflow ΔT Reduction goes From 12°F (Design) To 10.9°F (Actual) A reduction of 9%. Chiller 200 tons Chiller 200 tons

  21. Advantages Pressure Dependent Control Valves Design: 400 Ton CHW System @ 12˚ΔT 180 Ton Load (45%) 360 GPM Loop Flow CHWR CHWS (12˚ΔT) 54˚ 42˚ Chiller 200 tons VFD-Pump 90% Load KW=1.0k Arbitrary Value Chiller 200 tons VFD-Pump • Hold the load constant and vary the flow.

  22. Advantages Pressure Dependent Control Valves 180 Ton Load (45%) 396 GPM Loop Flow (+10%) CHWR CHWS (10.9˚ΔT) 52.9˚ 42˚ Chiller 200 tons VFD-Pump 90% Load KW=1.33k (396GPM/360GPM)3 = 1.33 (33% increase in pump power!) Chiller 200 tons VFD-Pump • An increase in flow results in: • Lower return temperature. • Reduced ΔT. • Increased pumping power.

  23. Advantages Pressure Dependent Control Valves Design: 400 Ton CHW System @ 12˚ΔT 180 Ton Load (45%) 414 GPM Loop Flow (+15%) CHWR CHWS (10.4˚ΔT) 52.4˚ 42˚ Chiller 200 tons VFD-Pump 45% Load An additional pump and chiller were started to meet the flow demand, not cooling demand! KW=0.76k (414GPM/360GPM)3 = 1.52 (52% increase in pump power!) Chiller 200 tons Chiller 200 tons VFD-Pump 45% Load KW=0.76k Also, a chiller receiving cold return water can’t load up!

  24. Belimo PI Valves Two Solutions for Today’s Hydronic Systems ePIV 2 ½” – 6” 105 GPM – 713 GPM PICCV ½” – 2” 0.5 GPM – 100 GPM

  25. Belimo Pressure Independent Valves Commissioning PICCV (Equal %) ePIV (Equal % or Linear; factory or field selectable)

  26. Belimo PI Valves PICCV Water passes through regulator Pressure is P2 (intermediate) Water exits valve Pressure is P3 (low) Water enters valve Pressure is P1 (high) Ports sense pressure drop and transfer it below regulator Low pressure pulls regulator down, against the spring force

  27. Belimo ePIV • Smart Actuator • Magnetic Flow Sensor • Flow Feedback and • Control Signal • LGCCV Valve

  28. Magnetic Flow Sensor • Measures changes to the induced voltage of a conductive fluid through a controlled magnetic field. • No moving parts or openings to clog or jam. • No maintenance.

  29. Actuator/Flow Tolerances Controller starts to control if delta "flow actual value" and "flow set value" > 5% (50% of the Flow tolerance)Controller stops to control if delta "flow actual value" and "flow set value" < 1% (10% of the Flow tolerance) Flow Accuracy +/- 6% of Vnom ExampleControl Signal Y = 100GPM (stable  no changes) If the measured Flow is higher then 105GPM  Actuator will correct until measured Flow is 101GPM. If the measured Flow is lower then 95GPM  Actuator will correct until measured Flow is 99GPM.

  30. Installation Considerations • 5 straight pipe diameters before the flow sensor • no straight pipe requirement on the outlet of the valve • STRAIGHT INLET LENGTHS • 2-1/2” ePIV = 12.5” 4” ePIV = 20” 6” ePIV = 30” • 3” ePIV = 15” 5” ePIV = 25

  31. Installation Considerations Actuator must be kept above horizontal!

  32. Introducing – the ePIVelectronic Pressure Independent Valve • Cost effective flow sensor technology combined with Belimo’s industry leading intelligent actuators and proven characterized valve technology • Both non-spring and electronic fail-safe proportional models • Provides all the benefits of PI valves (accurate flow control, improved efficiency at part load by reduced pumping power, improved waterside ΔT) • Reduced cost, less weight, less raw materials, more sustainable! • True flow measurement, available to DDC system through feedback wire • Glycol concentration up 50% has no effect on flow measurement • Can be configured for either linear or equal percentage flow characteristic with a simple program change.

  33. Belimo Field Programming Tool • Field adjustable programming tool allows: • PICCV • Control/feedback signal • Custom flows/adjust flows • Many other parameter adjustments • ePIV • Control/feedback signal • Custom flows/bias adjustment • Flow coefficient • Equal % or linear setting • Many other parameter adjustments ZTH-GEN No external power needed; no battery; powered by actuator 24 vac! Just plug it into actuator.

  34. Belimo PC Tool ePIV adjustments (PC Tool v3.5 and above) • Control/Feedback Signal Voltage • 2-10 VDC • 0-10 VDC • User selected • Flow Characteristic* • Equal Percentage • Linear • Maximum (Design) Flow • Bias Adjustment

  35. Commissioning Additional P/T PORT for verification of 5 psi (11.5 ft H20) minimum differential across the PI Valve. Minimum ΔP across valve must be verified with PI valve COMMANDED by DDC (or by programming tool) to design flow, not manually positioned!

  36. Commissioning Step 1: Ensure all strainers are clean and bypass valves are closed. Step 2: Command via DDC all PI valves to design flow. (Diversity assumed at 100%.) Step 3: Set distribution pump(s) to elevated speed by commanding ΔP setpoint or pump speed directly. Step 4: Find the “critical zone” (ie. the PI valve that has the least ΔP). Step 5: Increase or decrease pump speed/ΔP setpoint until critical zone has just over 5 psid (11.5 ft H20). The resulting ΔP at the system sensor will be the optimum system ΔP setpoint. Step 6: Verify total system flow is at design at main flow station (or by other method). Step 7: If flow is not within +/- 10% of design, start checking valves at terminal level, starting with largest valve(s) first (voltage, control signal, strainer, etc.)

  37. Commissioning • Belimo PI valves do NOT require that the entire system be placed in full design flow. Each PI valve flow can be verified individually with the rest of the system under normal control. • Command valve assembly to design. • Verify at least 5 psid across PI valve assembly. • Verify coil flow as per usual method (coil ΔP method, etc.) • Link for PI valve commissioning document: • www.piccv.com/pdf/PICCV_Application_Bulletin.pdf

  38. Questions?

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