1. CHW Optimization Case Studies
Presentation to:
HESGNY
CHW Optimization Case Studies
NYUMED & MSKCC By
WMGroup Engineers, P.C.
May 14, 2009

2. Today’s Topics
Discuss Case Histories of Chilled water system optimization for NYU MED and MSKCC
Discuss NYSERDA funding programs for energy analysis and grants for implementations

3. Background Both NYU MED and MSKCC had multiple chiller plants
Primary/Secondary and booster pumping
Low Delta T
Loss of chiller operating capacity

4. Background
NYSERDA funding under FlexTech program provided opportunities to review the system and make recommendations for improvements
NYSERDA provides 50% of the study costs directly to the engineer
In both cases study recommended to create a virtual central system and converting primary/secondary/booster pumping system to variable volume primary pumping system

5. The additional benefit is fewer chillers required for operation
Background
The projected energy savings, implementation costs and NYSERDA grants are as follows:
ITEM
NYU MED
MSKCC
Pump HP Savings
1,300
1,600
Annual cost savings
$460,000
$625,000
NYSERDA Grant
$580,000
$598,000
Simple payback
Less than 1 year
0.6 Years
The additional benefit is fewer chillers required for operation

6. What is involved in Optimization study?
Survey existing chiller plants and review System design Determine loads
Create a hydraulic model of the system
Evaluate pump head requirements
Review compatibility of system components
Evaluate system controls
Recommend short term and long term system modifications

7. General Overview of NYUMC Chiller Plants

8. Summary of Main Chiller Plants

9. Main Chilled Water Distribution
12”
Start of Distribution (Tisch Plant)
End of Distribution
* Drawing is not to scale (for illustration purposes only)

10. Site Chilled Water Distribution and Hydraulic Model

11. Hydraulic Analysis Measurements
Plants were surveyed, pipe lengths were measured, and fittings were counted
Distribution pipe lengths were estimated from satellite photos

12. Computerized Hydraulic Model
Piping survey data and load estimates were entered into Pipe2006 software
Model was run for multiple operating scenarios (newest plants operating, electric only, steam only, etc.)
Program calculates flow and pressure distribution using the Darcy-Weisbach formula
Output is dumped to a data file which must be evaluated with an Excel spreadsheet to interpret the results

13. Pipe2006 Software

14. Customized Excel Spreadsheets

15. Results of the Hydraulic Model
Most of the distribution is sized properly
Worst case pumping scenario is Smilow and Skirball at full load, Tisch offline.
The only major bottleneck under these conditions is in the import line to Tisch where 5,600 gpm is being forced through a 12” line
This may be alleviated in the future by adding an additional 12” line on supply (existing 12” Express Line on return would remain)

16. Current Distribution Bottleneck
Current peak flow through the 12” distribution pipe is 5,600 gpm, with a head loss of 5.5 ft per 100’
Maximum pressure drop for good engineering practice is 2.5 ft per 100’, or 3,680 gpm

17. NYUMC Existing CHW system
SMILOW
TISCH
SKIRBALL

18. NYUMC Modified CHW system
SMILOW
TISCH
Bypass or removal of pumps
Bypass or removal of pumps
SKIRBALL
Bypass or removal of pumps
Bypass or removal of pumps

19. Tisch Plant Existing CHW Flow Diagram

20. Tisch Plant Modified CHW Flow Diagram
Bypass or removal of pumps 20

21. Smilow Plant Modified CHW Flow Diagram
Bypass or removal of pumps
Bypass or removal of pumps 21

22. Skirball Plant Existing CHW Flow Diagram

23. Skirball Plant Modified CHW Flow Diagram
Bypass or removal of pumps
Bypass or removal of pumps
Valves Closed
Bypass NC 23

24. HCC Plant CHW Flow Diagram

25. Other Chiller Plants
Coles contains a 280 ton steam chiller and MSB contains a 280 ton electric chiller, both of which should be decommissioned
Coles and MSB loads should be served from the main distribution
New 400 ton electric chiller in Tisch 7th floor should be kept to maintain redundancy for the Operating Rooms

26. Summary of Chiller Plant Recommendations
Tisch, Smilow, and Skirball should all be converted to variable volume primary pumping
Most of the loads will be taken up by Skirball and Smilow, with Tisch used to meet any peaking loads

27. Chiller Plants Operation

28. Chiller Plants Operation

29. Compatibility of Components

30. System Compatibility
Mix of primary only, primary-secondary, and primary-booster pumping
A single pumping method (variable volume primary only) must be selected to ensure compatibility between systems
A consistent CHW supply and return temperature must be applied across the entire system (current plants have different ΔT’s)
Large air handlers should be checked for the controls of cooling coils

31. Chilled Water System ΔT
Tisch Plant is designed for 15°F ΔT
Smilow Plant is designed for 12°F ΔT
Many of the chilled water coils in the Medical Center are designed for 12°F ΔT
Higher ΔT (and lower pumping energy) may be possible with careful control of chilled water coils

32. Pump Removals

33. Pumps to be Removed or Decommissioned
Tisch PCHWP hp
Tisch PCHWP hp
Tisch PCHWP hp
Smilow P hp
Smilow P hp
Smilow P hp
Smilow P hp
Smilow P hp
Smilow P hp
Smilow P hp
Operating Room CHWP 20 hp
Skirball P hp
Skirball P hp
Skirball P hp
HCC Data Center Pump hp
MSB CHW Pump hp
Coles CHW Pump hp
SLH CHW Pump hp
AHU-27 Pump hp
HCC P hp
HCC P hp
A total of 1,290 hp of pumps will be removed from service, reducing peak electrical demand by 962 kW

34. System Controls

35. System Controls All pumps must work together hydraulically
All pumps should be controlled from a common differential pressure sensor located in the main distribution line
Multiple differential pressure sensors should be installed on the main distribution to determine through experimentation the ideal one for control
Optimum set-point for the pumps should be determined through experimentation

36. Executive Summary of Findings
MSKCC

37. 2. Total system Tertiary pump motor Hp = 531.5 Hp
Chiller Plant Summary
NOTE:
1. Total power values do not Include Standby pump power consumption values
2. Total system Tertiary pump motor Hp = Hp

38. Chiller Plant Summary
Loss of 650 Tons
from Design point

39. MSKCC Existing CHW system
Schwartz
Bobst
Memorial
Zuckerman HX CH
Haupt/OPB
Howard CH HX CH
Memorial 3rd Fl
Rad/Onc CH
Supply
Rockefeller
Not Connected
to main system
Return
Haupt / Infill

40. MSKCC Modified CHW system
Schwartz
Bobst
Memorial
Zuckerman
Bypass or removal of pumps HX
Bypass or removal of pumps
Bypass or removal of pumps CH
Haupt/OPB
Howard CH
Rad/Onc HX
Bypass or removal of pumps
Bypass or removal of pumps CH
Memorial 3rd Fl CH
Bypass or removal of pumps
Supply
Rockefeller
Connected to
Main system
Haupt / Infill
Return

41. Summary
A small first investment on your part of 50k to 70k will help you
To save hundreds of thousands a year in operating costs
Regain lost chiller operating capacity offsetting millions of dollars in future cost
Reduce overall energy and help to make our planet Greener
Contact any member of WM Group for a Free preliminary review of your system

42. The WMGroup Team
Thank you