Chilled Engineering SystemsChilled Engineering Systems“Helping You Be Cool”“Helping You Be Cool”

Ice Pond Refrigeration SystemIce Pond Refrigeration SystemDerek BrittenDerek BrittenRoger ConnollyRoger ConnollyBen FrancisBen FrancisAdam TrudeauAdam TrudeauSteve VinesSteve Vines

Final Presentation to the Mechanical EngineeringFinal Presentation to the Mechanical Engineering

Faculty, Students, Clients and GuestsFaculty, Students, Clients and Guests

April 7, 2005April 7, 2005

COCO22 Emissions Reductions Emissions Reductions

•2002 world FF emissions2002 world FF emissions– 24.5 billion metric tonnes

• 0.703 kg of CO0.703 kg of CO22 emitted per emitted per

KWh of energy produced KWh of energy produced

•Environmental stewardshipEnvironmental stewardship– “One Tonne Challenge” www.ge-at.iastate.edu

System OverviewSystem Overview• Evaluate the effectiveness of an ice pond systemEvaluate the effectiveness of an ice pond system

• Under development in Norway, JapanUnder development in Norway, Japan

• Potential to save energy and lower emissionsPotential to save energy and lower emissions– Kyoto Protocol

• System was created to compare results to vapor compression systemSystem was created to compare results to vapor compression system

System ComponentsSystem Components

•Ice ReservoirIce Reservoir

•Heat Exchanger & SupportHeat Exchanger & Support

•Reservoir CoverReservoir Cover

•Fan Coil Unit (FCU)Fan Coil Unit (FCU)

Selected PondSelected Pond

• 12 foot diameter 12 foot diameter

• 3 feet high3 feet high

• 8 tonnes of ice8 tonnes of ice

• Double linerDouble liner– Water tight vinyl– Protective tarp

Selected HX SupportSelected HX Support

• 1” x 4” wood planks1” x 4” wood planks

• 2” x 4” wood spacers2” x 4” wood spacers

• ¼” steel flat bars¼” steel flat bars

• Ice block supportIce block support

Selected Heat ExchangerSelected Heat Exchanger

• 1” M copper piping1” M copper piping

• 6” pipe spacing6” pipe spacing

• Length = 51.7mLength = 51.7m

• 20% PG mix20% PG mix

FCU SelectionFCU SelectionSystem BalancingSystem Balancing

• Load SelectionLoad Selection– Cooling Load: 12000Btu/hr per 500ft2 (USDOE 2004)

– ½ HVAC Lab ≈ 300ft2 2110W

– Qin = 2000W

• Trane FCU vs. CES HXTrane FCU vs. CES HX

FCU SelectionFCU SelectionModel ChosenModel Chosen

4 pass, 2 row horizontal FCU 4 pass, 2 row horizontal FCU

Ice Pond CoverIce Pond Cover

• Design:Design:– Self weight – 1.8kPa snow load

• Result: Result: – No significant snow accumulation– Withstood all environmental conditions

InsulationInsulation• Heat transfer major concernHeat transfer major concern

– Ice preservation during summer

• All reservoir components will be insulatedAll reservoir components will be insulated– Sub-floor– Reservoir wall– Protective cover– Pipes and hoses

Ice MakingIce Making

• Began Feb. 17Began Feb. 17

• Delayed due to warm temps - highs of 7Delayed due to warm temps - highs of 7°C°C

• Slow initial production ratesSlow initial production rates

Ice MakingIce Making

•Ice farms employed Feb. 21 Ice farms employed Feb. 21 – Production rate increased 2 - 3x

•Ice making completed in two weeksIce making completed in two weeks

Finished ProductFinished Product

• Core sample Core sample showing layersshowing layers

Remaining SystemRemaining SystemCompression FittingsCompression Fittings

Remaining SystemRemaining SystemInteriorInterior

Remaining SystemRemaining SystemAir SeparatorAir Separator

Remaining SystemRemaining SystemPump & Flow MeterPump & Flow Meter

MeasurementsMeasurements

• ΔΔT across pool inlet and outletT across pool inlet and outlet

• ΔΔT across FCU inlet and outletT across FCU inlet and outlet

• Control volume temperatureControl volume temperature

• Power consumed by systemPower consumed by system

Pool

FCU

Q

Q

sys

FCU

P

QCOP Q = mcpΔT

MeasurementsMeasurements

• 10 thermocouples located throughout system10 thermocouples located throughout system

Control VolumeControl Volume

Closed Loop TestingClosed Loop Testing

• 3 short 2 hour tests3 short 2 hour tests

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

Closed Loop TemperaturesClosed Loop Temperatures

-5.0

0.0

5.0

10.0

15.0

20.0

25.0

0 200 400 600 800 1000

Elapsed Time (min)

Tem

per

atu

re (

C)

Inside Amb.

Pool Inlet

Mid. HX

Pool Outlet

Melt Water

Outside Amb.

FCU Inlet

FCU Outlet

FCU Air

Large ControlVolume

Closed Loop PowerClosed Loop Power

1000

1250

1500

1750

2000

2250

2500

2750

3000

0 200 400 600 800 1000

Elapsed Time (min)

Co

oli

ng

Po

we

r (W

)

0

1

2

3

4

5

6

7

8

9

10

qFCU

qPool

COP

SystemEfficiency

CO

P a

nd

Sy

ste

m E

ffic

ien

cy

Closed Loop TestingClosed Loop Testing

• 24 hours24 hours

• Average FCU cooling rate = Average FCU cooling rate = 1660W1660W

• Average pool cooling rate = Average pool cooling rate = 1989W1989W

• Average COP = Average COP = 7.227.22

• Average system efficiency = Average system efficiency = 83.68%83.68%

• Estimated Estimated 400 kg400 kg of ice melted of ice melted

• Average control volume temp = Average control volume temp = 20.9420.94°C°C

Open LoopOpen Loop

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

• Compare systemsCompare systems

• Flow rate increasedFlow rate increased– 2.9gpm – Less head loss– Less viscous

Open Loop TestingOpen Loop Testing

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

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

Open Loop TemperaturesOpen Loop Temperatures24 Hour Open Loop Test - 2500W Heat Input, Maximum Flow RateTemperatures vs. Time

March 29, 2005

0.0

5.0

10.0

15.0

20.0

25.0

0 200 400 600 800 1000 1200 1400

Elapsed Time (min)

Te

mp

era

ture

(C

)

Inside Amb.

Pool Inlet

Pool Outlet

Melt Water

Outside Amb.

FCU Inlet

FCU Outlet

FCU Air

Large ControlVolume

Open Loop PowerOpen Loop Power

1500

1750

2000

2250

2500

2750

3000

3250

3500

0 200 400 600 800 1000 1200 1400

Elapsed Time (min)

Co

oli

ng

Po

we

r (W

)

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

qFCU

qPool

COP

SystemEfficiency

CO

P a

nd

Sy

ste

m E

ffic

ien

cy

Open Loop TestingOpen Loop Testing

• 24 hours24 hours

• Average FCU cooling rate = Average FCU cooling rate = 2264W2264W

• Average pool cooling rate = Average pool cooling rate = 2892W2892W

• Average COP = Average COP = 9.849.84

• Average system efficiency = Average system efficiency = 78.45%78.45%

• Estimated Estimated 815 kg815 kg of ice melted of ice melted

• Average control volume temp = Average control volume temp = 19.3519.35°C°C

Project AssessmentProject 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 > COP V/C COP = 10 (3x Greater)

ConclusionsConclusions

• All tests had a COP > 5All tests had a COP > 5

• Little to no transient operating zone – reached Little to no transient operating zone – reached steady state quicklysteady state quickly

• More melt water = less performanceMore melt water = less performance

• Open loop is better than closed loopOpen loop is better than closed loop– ΔT between working fluid and air – Mass flow rate

– Cp of working fluidQ = mcpΔT

ConclusionsConclusions

• Need a powerful system for low temperaturesNeed a powerful system for low temperatures

• No energy consumed for ice making No energy consumed for ice making

• System efficiency high because of cool System efficiency high because of cool ambient temperatures during testingambient temperatures during testing

BudgetBudget

Estimated Budget: $5000.00 Estimated Budget: $5000.00

Actual CostsActual CostsIce ReservoirIce Reservoir $1235.73$1235.73

Piping and HX’sPiping and HX’s $2078.06$2078.06

Ice/ HX SupportIce/ HX Support $238.00$238.00

Pool CoverPool Cover $764.70$764.70

Testing EquipmentTesting Equipment $826.59$826.59

Miscellaneous Miscellaneous $270.42$270.42

Grand TotalGrand Total $5413.51$5413.51

COCO22 Emissions Reductions Emissions Reductions

•Environmental stewardshipEnvironmental stewardship– “One Tonne Challenge”

•OUR SYSTEMOUR SYSTEM

– Reduced by 3x!

www.ge-at.iastate.edu

RecommendationsRecommendations

• Full scale modelFull scale model• Melt waterMelt water

– No heat exchanger• Increase space between pool inlet & outletIncrease space between pool inlet & outlet

– Colder outlet temperatures• Higher flow ratesHigher flow rates

– Turbulent instead of laminar flow– Increases rate of heat transfer

• More durable reservoirMore durable reservoir– Not dependent on vinyl liner

• Automated ice making systemAutomated ice making system

DemonstrationDemonstration

Special Thanks To:Special Thanks To:

• Mr. Richard RachalsMr. Richard Rachals• Dr. Murat KoksalDr. Murat Koksal• Albert MurphyAlbert Murphy• Greg JollimoreGreg Jollimore• Dr. Peter AllenDr. Peter Allen• Import Tool CorporationImport Tool Corporation• Jeff MacNeil of TraneJeff MacNeil of Trane• Mike Trudeau of HCDJMike Trudeau of HCDJ

Questions?Questions?