1. Energy Valve Delta T Manager
Belimo Energy Valve™ Delta T Manager™
Energy Valve Delta T Manager

2. Energy Valve Delta T Manager
Presentation Agenda
Low Delta T at the Coil
Some of Low Delta T Causes
Low Delta T
Cost of Overflowing Coil
Cost of Chiller Staging
Cost of Over Pumping
Occupant Comfort
Does it Really Work?
Benefits
Energy Valve Delta T Manager

3. Energy Valve Delta T Manager
Low Delta T at the Coil
Low Coil Delta T = Inefficient
Heat Transfer
Increase GPM >> No Increase in
Energy output
More Pump HP >> Reduction in
Plant Efficiency
Energy Valve Delta T Manager

4. Low Delta T Some of Low Delta T Causes
Low Control Set Point
Fouled Coils
Low Valve Authority
Causes of Low Delta T
Low Control Air Temperature Set Point: One of the main causes of Low Delta T as the system tries to achieve the low air temperature by overflowing the coil.
Fouled Coiler: Coils degrade over time. Without proper maintenance, the coil output is reduced leading to low heat transfer.
Oversized Valves: Have low valve authority. This authority is exasperated during low load conditions.
Using Bypass or 3-Way Valves: Reduces delta T across the coil. Increase in Supply Water Temperature. This increase reduces the coil power. Thus produce less energy.
Energy Valve Delta T Manager

5. Low Delta T Coil Power vs Delta T Behavior
Explanation of Coil Curve in relation to Delta T Curve.
Energy Valve Delta T Manager

6. Low Delta T Cost of Overflowing the Coil…1
335000
330000 2
Coil
Power Curve
Click: Here is an example of a power curve.
Click: and a Delta T curve.
Click: When we take a late point on the power curve where flow is 65 gpm. You’ll notice that the Power output was 335KBTU and the Delta T is 10.5°F.
Click: Now, When we take another earlier point on the power curve where flow is 55 gpm. You’ll notice that the Power output was 330KBTU and the Delta T is 12°F.
12°F
Delta T Curve
10.5°F
55 GPM
65 GPM
Energy Valve Delta T Manager

7. Low Delta T Cost of Overflowing the Coil…1 2 Δ
BTUh
330,000
335,000
1.5%
GPM
55 GPM
65 GPM
18%
Pump hp
Hp increase = (65/55)3
65% ?
Energy Valve Delta T Manager

8. Delta T Manager™ Cost of Chiller Staging
Chiller Plant Efficiency
Design Condition
Design ΔT=12oF (54oF - 42oF)
360 GPM
1 Chiller, 90% Load (180 Ton)
Scenario: Chiller plant with 2 x 200 ton chillers in parallel, each with VFD pump
Imagine a scenario where a 45% load on a 2 chiller plant yields one chiller operating at 90% based on 432 gpm and a delta T of 12 (all at design)
In the next slide we are going to show how a small reduction in delta T, pushes this system in to the waste zone and causes addition chiller resources to be used to satisfy the same load
360 GPM Loop flow
Energy Valve Delta T Manager

9. Delta T Manager™ Cost of Chiller Staging
Chiller Plant Efficiency
Low ΔT
ΔT=10.4oF (52.4oF - 42oF)
415 GPM
2 Chillers, 45% Load (180 Ton)
Low Delta T: same load (180 tons) now has:
10.4 delta T,
requires 498 GPM (15% overflow)
2 chillers at 45% each
A second chiller staged based on flow, not load.
Wasted chiller capacity…
We already discussed pump affinity, but you can re-enforce, 15% overflow = 52% more pump HP
415 GPM Loop flow
No change to the load, but a 2nd Pump and 2nd Chiller are started.
Energy Valve Delta T Manager

10. Low Delta T Cost of Over Pumping
Delta T Manager Signal
Wasted Pumping
DDC Signal
Section 1 (animation 1): Library Startup cycle, immediate high demand causes overflow at the coils (flow past saturation point). Orange line and blue line are on top of each other. Delta T drops passed limit of 12F and past the 2F dead band… delta T manager engages when the measurement hits 10F
Section 2 (animation 2): Delta T manager causes the valve to close and the flow to reduce, point out that the orange line represent the actual flow of the valve reducing by nearly 1/3. The delta T raises from around 9F to 12F. Around the same time, the space is satisfied (note that the blue line, building control, begins to request less flow indicating a satisfied state). The entire process took about 30 minutes.
Section 3 (animation 3): We believe that at about 10:45 to 11:00 am the library opened and became under load (student bodies). The behavior of the control system is nearly identical to that of the start up cycle. It immediately asks for too much water and creates another low delta T scenario.
Section 4 (animation 4): Delta T manager fixes the issue and stays engaged all day. We recognize that the room condition is satisfied, because the control set point for the valve stabilizes, if demand were not met, the call for valve flow would continue to increase.
Delta T Manager On
Delta T Manager On
Energy Valve Delta T Manager

11. Delta T Manager™ Occupant Comfort
“How can I let the Delta T Manager limit flow if it doesn’t measure discharge air temperature?
What about occupant comfort?!?”
Click: Here is an example of a power curve.
Click: and a Delta T curve.
Click: When we take a late point on the power curve where flow is 65 gpm. You’ll notice that the Power output was 335KBTU and the Delta T is 10.5°F.
Click: Now, When we take another earlier point on the power curve where flow is 55 gpm. You’ll notice that the Power output was 330KBTU and the Delta T is 12°F.

12. Delta T Manager™ Occupant Comfort
Delta T Manager adjusts the valve if the ΔT drops below the set point in order to maintain peak coil efficiency
Virtually No Power Reduction
335000
325000
Delta T Curve
Power Saturation
Power Curve
Delta T
Set Point
Click: Here is an example of a power curve.
Click: and a Delta T curve.
Click: When we take a late point on the power curve where flow is 65 gpm. You’ll notice that the Power output was 335KBTU and the Delta T is 10.5°F.
Click: Now, When we take another earlier point on the power curve where flow is 55 gpm. You’ll notice that the Power output was 330KBTU and the Delta T is 12°F.
55 GPM
65 GPM
Energy Valve Delta T Manager

13. Energy Valve Delta T Manager
Does it really work?
Energy Valve Delta T Manager

14. Case Study Large Tech Company in North Carolina
DT Management
96 GPM
Flow Control
144 GPM
Introduce each data set by its control/limiting method
Position Control (functions like CCV)
Flow Control (functions like ePIV)
Flow Control with Delta T limiting
Let’s evaluate the performance of each at a given load of 60 tons
Position Control uses 240 GPM to achieve 60 tons
Flow Control uses 144 GPM to achieve 60 tons
Flow Control with Delta T limiting uses only 96 GPM to achieve the same load of 60 tons
Position control uses 2.5 times the amount of water (than delta T management) to achieve the same load!
240 GPM
Position Control
Energy Valve Delta T Manager

15. Case Study MIT University Hayden Library - Boston, MA
Building and Project Details
150,000 sq. ft. on 3 floors
6 AHU provide majority of the cooling
Results
Aug 9 - Oct 9, 2010
DT = 6.15°F
Aug 9 - Oct 9, 2011
DT = 12.14°F
The average delta T in Hayden Library AHUs went from 6.15 to with use of EV.
Load to Flow ratio indicates the same load can be satisfied with less water… using less water means lower demand on chiller plant… this means freed capacity to cool additional loads
Independent engineering study concluded that MIT could save about $1.5M/yr campus wide is all delta T issues were resolved
Mention – MIT You Tube Video - and
Energy Valve Delta T Manager

16. Case Study University of Miami Hospital
Building and Project Details
Rosenstiel Building
11 AHUs
2600 Tons of Cooling
Over 10,000 GPM
Results
Delta T raised from
5.5°F to 10.5°F
Flow ~ 5600 GPM
Estimated $66,000/yr savings
Estimated 2.9 year payback
Energy Valve Delta T Manager

17. Delta T Manager™ Benefits
Coil
ΔT Managing for peak coil efficiency
Optimization in retro-fit applications
Chiller Plant
Improved chilled water plant efficiency
Released chiller capacity
Pump
Reduced pump energy
Occupant Comfort
No reduction in supplied energy
Belimo Americas
Danbury, Connecticut

18. Energy Valve Delta T Manager
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Energy Valve Delta T Manager