daq calibration for heat exchanger calibration of cold/hot flow rate and temperature
DESCRIPTION
DAQ Calibration for Heat Exchanger Calibration of Cold/Hot Flow Rate and Temperature. UTC ENCH/ENEV 435 11/25/03 Greg Kirton Kevin Zitzow Phuong Mai. Objectives. Calibrate Cold Water Flow Rates from DAQ with Measured Flow Rates - PowerPoint PPT PresentationTRANSCRIPT
DAQ Calibration for Heat Exchanger
Calibration of Cold/Hot Flow Rateand Temperature
UTCENCH/ENEV 435
11/25/03
Greg KirtonKevin ZitzowPhuong Mai
Objectives
Calibrate Cold Water Flow Rates from DAQ with Measured Flow Rates
Calibrate Hot Water Flow Rates from DAQ with Measured Flow Rates
Calibrate Temperatures from DAQ with Measured Temperatures
Heat Exchanger in UTC Lab
FT=Flow Transmitter S=SolenoidTT= Temp TransmitterCW=Cold WaterW/H=Water HeaterCWS=Cold Water SupplyCWR=Cold Water Return
Schematic of Heat Exchanger
Procedure for Measurements
A stopwatch was used to keep time A 1000 ml graduated cylinder was used to measure
volume Measured volume of water obtained in 10 seconds. Varied
% Opening of Cooling Water Valve % Hot Water Pump Speed
4 measurements were made for each setting
Data Analysis
Measurements were averaged and error was calculated using student’s T equation.
http://chem.engr.utc.edu/engr329/Lab-manual/Students-T.htm
Computer DAQ was averaged and standard deviation was calculated in Excel DAQ error was reported as 2xSTDEV
Cold Water Flow Calibration
Cold Water Flow Data
0
2
4
6
8
10
12
14
0 20 40 60 80 100
% Valve Open
Flow
Rat
e (lb
/min
)
Data from DAQ
Measured Data
Cold Water Flow Rate Calibration
y = 1.4981x + 0.1922R2 = 0.9944
0
2
4
6
8
10
12
0 2 4 6 8 10 12
DAQ Flow rate (lb/min)
Mea
sure
d Fl
ow R
ate
(lb/m
in)
Hot Water Flow Calibration
Hot Water Flow Data
0
2
4
6
8
10
0 20 40 60 80 100
% Pump Speed
Flow
rate
(lb/
min
)
Measured Data
DAQ
Hot Water Flow Rate Calibration
y = 0.0255x2 + 1.2302x - 2.2253R2 = 0.9942
0
2
4
6
8
10
0 2 4 6 8 10DAQ (lb/min)
Mea
sure
d (lb
/min
)
Temperature Calibration
Insulation
Tube Side Port B
Tube Side Port A
Shell Side Port B
Shell Side Port A
Temperature Data
Location Measured (oC) DAQ (oC)CWS From Lab Sink 22.5 21RTD Shell Side Port A 46 47RTD Shell Side Port B 31.5 31RTD Tube Side Port A 30.8 31.7RTD Tube Side Port B 17.7 16.7
Overall Heat Transfer Coefficient of Heat Exchanger
Objectives
Compare total heat transfer rates of the hot and cold streams.
Determine the overall heat transfer coefficient.
Pictures of the Heat Exchanger
Hot water in
Cold water in
Tube bundle
Heat Transfer Properties
55 tubes Tube Volume = 143 cc Tube Length = 506 mm Total heat transfer area = 0.27 m2
Heat Transfer Diagram
Thot,inThot,out
Tcold,in Tcold,out
q
lmTUAq
Log Mean Temperature
))()(
ln(
)()()/ln(
,,
,,
,,,,
12
12
ocih
icoh
ocihicohlm
TTTT
TTTTTTTT
T
Heat Transfer Rate Equations
)(
)(
,,,
,,,
ihohchhh
icoccpcc
TTcmq
TTcmq
1st Run Input = 75%
Hot water mass flow rate (HWS) of 0.4124kg/s
CW valve open = 60 % Cold Water mass flow rate (CWS) of 0.080kg/s
q and U Results of 1st Run
qc =5.76 kW qh = 3.37 kW Uc = 1352 W/m2K Uh= 792 W/m2K
2nd Run
Input = 40% Hot water mass flow rate (HWS) of 0.0258 kg/s
CW valve open = 40 % Cold water mass flow rate (HWS) of 0.0505
kg/s
q and U Results of 2nd Run
qc =2.33 kW qh = 2.25 kW Uc = 532 W/m2K Uh= 514 W/m2K
Overall Heat Transfer Coefficient (U)
0
200
400
600
800
1000
1200
1400
1
U (W
/m2K)
1). HWS = 0.04124kg/s and CWS = 0.080 kg/s2). HWS = 0.0258 kg/s and CWS = 0.0505 kg/s
1st
2nd
1st
2nd
Hot FlowCold Flow
Total Heat Transfer Rate (q)
0
1
2
3
4
5
6
7
1
q(kW
) Hot Flow Cold Flow
1st2nd 2nd
1st
1). HWS = 0.04124kg/s and CWS = 0.080 kg/s2). HWS = 0.0258 kg/s and CWS = 0.0505 kg/s
Conclusions
1st run: qc and qh are not closed. 2nd run: qc and qh are closed. 1st run: Uc and Uh are not closed. 1st run: Uc and Uh are closed. U increases as HWS and CWS increase.
1). HWS = 0.04124kg/s and CWS = 0.080 kg/s2). HWS = 0.0258 kg/s and CWS = 0.0505 kg/s
Questions
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