Stirling Refrigeration

ME 498 - Senior LaboratoryNovember 16, 2004

Nicholas Taylor

Overview

Background and theory of the Stirling Cooler

Experimental Set-up and Procedure

Results

Objectives

Operate Global Cooling Model 100B Stirling Cooler

Use thermodynamic principles to analyze the performance

Calculate COP, Qrejected, Qlifted

Background

Model 100B free piston Stirling Cooler

High conversion between mechanical and thermal energy

AC linear motor drives the piston

Working gas – helium

Background

Theory

Coefficient of Performance

Stirling

LiftedR

W

QCOP

dt

dTmcQ plifted

liftedrejectedstirling QQW

Theory

Finding Qrejected

)( inletoutletprejected TTcmQ

Vm water

Experimental Apparatus

Water ToSink

Water FromSink

DigitalPowerMeter

Wire Box

Variac Auto-Transformer

Variac Auto-Transformer

Fluke 77DMM

Fluke 87DMM

OmegaTemperature

Controller Omega TemperatureMeasurement Device

Model 100BStirlingCooler

Flowmeter

Thermocouple

ThermofoilHeater

Procedure

Measure flow rate Prepare data acquisition system Increase voltage to the stirling cooler, to

begin cooling Record data until the temperature

reaches -30°C, activate the heater and reach equilibrium at -20°C

Turn off equipment

Results

Temperature vs. Time

COPR for 5°C, 0°C, -10°C, and -23°C

Compare COP found to COP from Global Cooling

COPR, Wstirling, and Qrejected at equilibrium

Compare COP at equilibrium with COPcarnot

Uncertainty Analysis

Results

Temperature vs. Time

-40.00

-30.00

-20.00

-10.00

0.00

10.00

20.00

30.00

0 200 400 600 800 1000 1200 1400 1600 1800

Time (sec)

Tem

per

atu

re (

C)

Results

Temperature vs Time(during cooling)

y = 281.45e-0.0003x

0.00

100.00

200.00

300.00

400.00

0 100 200 300 400 500 600 700 800

Time (sec)

Tem

per

atu

re (

K)

Results

Global Cooling

Temp Time Cp m dT/dt Qlifted Wstirling COP Input COP % diff.

(deg C) (sec) (J/kJ*C) kg   (W) (W)   (W)    

5 79 380.23 0.27 -0.087 8.88 9.22 0.963 6 2.33 58.66

0 118 379 0.27 -0.088 8.954 9.2 0.973 5 2.06 52.75

-10 219 376.42 0.27 -0.090 9.167 9.11 1.006 3 1.06 5.07

-23 419 372.8 0.27 -0.096 9.633 9.68 0.995 4 1.18 15.67

Results

Equilibrium Test

Qreject 32.318

Qlifted 12.204

Wstirling 20.114

COP 0.607

COP carn. 2.809

% difference 78.398

Uncertainty

Uncertainty of COP

Uncertainty of Qlifted

Uncertainty of Qrejected

Uncertainty of Vdot

Uncertainty

% ωCOP = 1.2%

ωQrejected = 4.61 (32.318)

ωVdot = 2.85E-8

ωQlifted = 0.11 (12.204)

ωCOP = 6.18E-3 (.607)

Uncertainty

Qlifted

Component Value Uncertainty

V 10.8 0.01

I 1.13 0.01

Component Qlifted n (n+dn) Qlifted(n+dn) dQlifted/dn

V 12.204 10.8 10.8 12.204 1.13

I 12.204 1.13 1.13 12.204 10.80

ωQlifted 0.11

Conclusions

Learned a practical use of a Stirling Cooler

Found COP, Qrejected, and Qlifted

Found the uncertainty in measurements

Recommend comparing to a traditional refrigeration cycle

References

http://www.globalcooling.com

http://132.235.18.152/seniorlab