transient response
DESCRIPTION
Transient Response. Paul Black, Mark Eilertsen, Evan Jones. How long will it take for ice cold water to reach room temperature ?. Measured. Prediction. K eq. Lumped Capacitance Approximate Solution. Transient Response. s. Approximate Solution Fo > .2. Lumped Capacitance Bi < .1. - PowerPoint PPT PresentationTRANSCRIPT
Transient ResponseTransient Response
Paul Black, Mark Eilertsen, Evan JonesPaul Black, Mark Eilertsen, Evan Jones
How long will it take for How long will it take for ice cold water to reach ice cold water to reach room room temperaturetemperature??
Measured
Transient Response
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275
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285
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300
0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00
Time (hrs)
Tem
pera
ture
(K)
T∞
T (measured)
KKeq eq
Prediction
Lumped CapacitanceLumped Capacitance
Approximate SolutionApproximate Solution
Transient Responce
270
275
280
285
290
295
300
0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00
Time (hrs)
Te
mp
era
ture
(K
) T∞
T (measured)
T (Lumped C)
T (4 term aprox.)
Lumped Capacitance Lumped Capacitance Bi < .1Bi < .1
Approximate Approximate
SolutionSolution Fo > .2 Fo > .2
sTransient Response
Comparison of Multiple Terms in the Approximate Method
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275.00
280.00
285.00
290.00
295.00
300.00
0 10 20 30 40 50 60 70 80 90 100
Time (hrs)
Te
mp
era
ture
(K
) Temp (aprox 1 term)
Temp (aprox 2 term)
Temp (aprox 3 term)
Temp (aprox 4 term)
No Difference
ConclusionConclusionCooler kept food cool for Cooler kept food cool for 146 hrs146 hrs
Lumped capacitance Lumped capacitance –Initial response (Bi<.1)Initial response (Bi<.1)
Approximate solutionApproximate solution–Response after some time (Fo>.2)Response after some time (Fo>.2)–One term is good enoughOne term is good enough