Chilled Engineering Systems

1
Chilled Engineering SystemsHelping You Be Cool

• Ice Pond Refrigeration System

Derek Britten Roger Connolly Ben Francis Adam
Trudeau Steve Vines
Final Presentation to the Mechanical
Engineering Faculty, Students, Clients and
Guests April 7, 2005
2
CO2 Emissions Reductions

• 2002 world FF emissions
• 24.5 billion metric tonnes
• 0.703 kg of CO2 emitted per KWh of energy
  produced
• Environmental stewardship
• One Tonne Challenge

www.ge-at.iastate.edu
3
System Overview

• Evaluate the effectiveness of an ice pond system
• Under development in Norway, Japan
• Potential to save energy and lower emissions
• Kyoto Protocol
• System was created to compare results to vapor
  compression system

4
System Components

• Ice Reservoir
• Heat Exchanger Support

• Reservoir Cover
• Fan Coil Unit (FCU)

5
Selected Pond

• 12 foot diameter
• 3 feet high
• 8 tonnes of ice
• Double liner
• Water tight vinyl
• Protective tarp

6
Selected HX Support

• 1 x 4 wood planks
• 2 x 4 wood spacers
• ¼ steel flat bars
• Ice block support

7
Selected Heat Exchanger

• 1 M copper piping
• 6 pipe spacing
• Length 51.7m
• 20 PG mix

8
FCU SelectionSystem Balancing

• Load Selection
• Cooling Load 12000Btu/hr per 500ft2 (USDOE 2004)
• ½ HVAC Lab 300ft2 2110W
• Qin 2000W
• Trane FCU vs. CES HX

9
FCU SelectionModel Chosen

• 4 pass, 2 row horizontal FCU

10
Ice Pond Cover

• Design
• Self weight
• 1.8kPa snow load
• Result
• No significant snow accumulation
• Withstood all environmental conditions

11
Insulation

• Heat transfer major concern
• Ice preservation during summer
• All reservoir components will be insulated
• Sub-floor
• Reservoir wall
• Protective cover
• Pipes and hoses

12
Ice Making

• Began Feb. 17
• Delayed due to warm temps - highs of 7C
• Slow initial production rates

13
Ice Making

• Ice farms employed Feb. 21
• Production rate increased 2 - 3x
• Ice making completed in two weeks

14
Finished Product

• Core sample showing layers

15
Remaining SystemCompression Fittings
16
Remaining SystemInterior
17
Remaining SystemAir Separator
18
Remaining SystemPump Flow Meter
19
Measurements
Q mcp?T

• ?T across pool inlet and outlet
• ?T across FCU inlet and outlet
• Control volume temperature
• Power consumed by system

20
Measurements

• 10 thermocouples located throughout system

21
Control Volume
22
Closed Loop Testing

• 3 short 2 hour tests

• One 24 hour test
• Test with maximum flow rate 2.3gpm 2100W heat
  input

23
Closed Loop Temperatures
24
Closed Loop Power
25
Closed Loop Testing

• 24 hours
• Average FCU cooling rate 1660W
• Average pool cooling rate 1989W
• Average COP 7.22
• Average system efficiency 83.68
• Estimated 400 kg of ice melted
• Average control volume temp 20.94C

26
Open Loop

• Converted system to open loop bypassed heat
  exchanger due to mild temperatures

• Compare systems
• Flow rate increased
• 2.9gpm
• Less head loss
• Less viscous

27
Open Loop Testing

• Same 2 hour tests as closed loop
• One 2 hour test at maximum flow rate

• One 24 hour test
• Test with maximum flow rate 2.9gpm 2500W heat
  input

28
Open Loop Temperatures
29
Open Loop Power
30
Open Loop Testing

• 24 hours
• Average FCU cooling rate 2264W
• Average pool cooling rate 2892W
• Average COP 9.84
• Average system efficiency 78.45
• Estimated 815 kg of ice melted
• Average control volume temp 19.35C

31
Project Assessment
Design Requirement Delivered To Client
Create Working Model to Evaluate Ice Pond System Yes
Volume of Approximately 10 12 m3 10 m3 Reservoir
Overall HX Heat Transfer U 100W/m2K U 130W/m2K
Cool at a Rate of 2kW Max Rate of 2.27kW
System Efficiency of 30 System Efficiency of 80
Budget 5000 Total Cost 5413.51
COP gt COP V/C COP 10 (3x Greater)
32
Conclusions

• All tests had a COP gt 5
• Little to no transient operating zone reached
  steady state quickly
• More melt water less performance
• Open loop is better than closed loop
• ?T between working fluid and air
• Mass flow rate
• Cp of working fluid

Q mcp?T
33
Conclusions

• Need a powerful system for low temperatures
• No energy consumed for ice making
• System efficiency high because of cool ambient
  temperatures during testing

34
Budget

• Estimated Budget 5000.00
• Actual Costs

Ice Reservoir 1235.73
Piping and HXs 2078.06
Ice/ HX Support 238.00
Pool Cover 764.70
Testing Equipment 826.59
Miscellaneous 270.42
Grand Total 5413.51
35
CO2 Emissions Reductions

• Environmental stewardship
• One Tonne Challenge
• OUR SYSTEM
• Reduced by 3x!

www.ge-at.iastate.edu
36
Recommendations

• Full scale model
• Melt water
• No heat exchanger
• Increase space between pool inlet outlet
• Colder outlet temperatures
• Higher flow rates
• Turbulent instead of laminar flow
• Increases rate of heat transfer
• More durable reservoir
• Not dependent on vinyl liner
• Automated ice making system

37
Demonstration
38
Special Thanks To

• Mr. Richard Rachals
• Dr. Murat Koksal
• Albert Murphy
• Greg Jollimore
• Dr. Peter Allen
• Import Tool Corporation
• Jeff MacNeil of Trane
• Mike Trudeau of HCDJ

39
Questions?
40
(No Transcript)