DAQ Calibration for Heat Exchanger Calibration of Cold/Hot Flow Rate and Temperature UTC ENCH/ENEV /25/03 Greg Kirton Kevin Zitzow Phuong 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=Solenoid TT= Temp Transmitter CW=Cold Water W/H=Water Heater CWS=Cold Water Supply CWR=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.  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

Hot Water Flow Calibration

Hot Water Flow Data

Temperature Calibration

Insulation

Tube Side Port B Tube Side Port A Shell Side Port B Shell Side Port A

Temperature Data

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 m 2

Heat Transfer Diagram T hot,in T hot,out T cold,in T cold,out q

Log Mean Temperature

Heat Transfer Rate Equations

1 st Run  Input = 75% Hot water mass flow rate (HWS) of kg/s  CW valve open = 60 % Cold Water mass flow rate (CWS) of 0.080kg/s

q and U Results of 1 st Run  q c =5.76 kW  q h = 3.37 kW  U c = 1352 W/m 2 K  U h = 792 W/m 2 K

2 nd Run  Input = 40% Hot water mass flow rate (HWS) of kg/s  CW valve open = 40 % Cold water mass flow rate (HWS) of kg/s

q and U Results of 2 nd Run  q c =2.33 kW  q h = 2.25 kW  U c = 532 W/m 2 K  U h = 514 W/m 2 K

1). HWS = kg/s and CWS = kg/s 2). HWS = kg/s and CWS = kg/s 1st 2nd 1st 2nd Hot Flow Cold Flow

Hot Flow Cold Flow 1st 2nd 1st 1). HWS = kg/s and CWS = kg/s 2). HWS = kg/s and CWS = kg/s

Conclusions  1 st run: q c and q h are not closed.  2 nd run: q c and q h are closed.  1 st run: U c and U h are not closed.  1 st run: U c and U h are closed.  U increases as HWS and CWS increase. 1). HWS = kg/s and CWS = kg/s 2). HWS = kg/s and CWS = kg/s

Questions ?????