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SOLTEQ®
EQUIPMENT FOR ENGINEERING EDUCATION
EXPERIMENTAL MANUAL
HEAT EXCHANGER TRAINING APPARATUS MODEL: HE158C
SOLUTION ENGINEERING SDN. BHD. NO.3, JALAN TPK 2/4, TAMAN PERINDUSTRIAN KINRARA, 47100 PUCHONG, SELANGOR DARUL EHSAN, MALAYSIA. TEL: 603-80758000 FAX: 603-80755784 E-MAIL:
[email protected] WEBSITE: www.solution.com.my 236-0510-HE
Table of Contents Page List of Figures ....................................................................................................................................... i List of Tables ....................................................................................................................................... ii 1.0 INTRODUCTION ........................................................................................................................... 1 2.0 GENERAL DESCRIPTION 2.1 2.2
Description and Assembly .................................................................................................. 2 Experimental Capabilities ................................................................................................... 5
2.3
Process Instruments ........................................................................................................... 5
2.4
Overall Dimensions ............................................................................................................. 6
2.5
General Requirements ........................................................................................................ 6
3.0 INSTALLATION AND COMMISSIONING………………………………………………………….. .. 7 3.1
Installation procedures ....... ……………………………………………………………………..7
3.2
Commissioning procedures……………………………………………………………………..7
4.0 SUMMARY OF THEORY 4.1
Shell & Tube Heat Exchanger ............................................................................................ 8
4.2 4.3
Spiral Heat Exchanger ...................................................................................................... 17 Concentric (Double Pipe) Heat Exchanger....................................................................... 17
4.4
Plate Heat Exchanger ....................................................................................................... 18
5.0 GENERAL OPERATING PROCEDURES .................................................................................. 21 5.1 General Start-up Procedures ............................................................................................ 21 5.2
General Shut-down Procedures ....................................................................................... 21
6.0 EXPERIMENTAL PROCEDURE 6.1 Experiment 1.A: Counter-Current Shell & Tube Heat Exchanger. ................................... 22 6.2
Experiment 1.B: Co-Current Shell & Tube Heat Exchanger............................................. 24
6.3
Experiment 2.A: Counter-Current Spiral Heat Exchanger ................................................ 26
6.4 6.5
Experiment 2.B: Co-Current Spiral Heat Exchanger ........................................................ 27 Experiment 3.A: Counter-Current Concentric Heat Exchanger........................................ 28
6.6
Experiment 3.B: Co-Current Concentric Heat Exchanger ................................................ 29
6.7
Experiment 4.A: Counter-Current Plate Heat Exchanger ................................................. 30
6.8
Experiment 4.B: Co-Current Plate Heat Exchanger ......................................................... 31
7.0 EQUIPMENT MAINTENANCE ................................................................................................... 32 8.0 SAFETY PRECAUTIONS ........................................................................................................... 32 9.0 REFERENCES ............................................................................................................................ 33 APPENDIX A: EXPERIMENTAL DATA SHEETS APPENDIX B: CONVERSION FACTORS APPENDIX C: HEAT EXCHANGER CALCULATION DATA APPENDIX D: RESULTS SUMMARY APPENDIX E: SAMPLE CALCULATIONS APPENDIX F: TEMPERATURE SENSOR CALIBRATION
List of Figures
Page
Figure 1
Schematic Diagram for Heat Exchanger Training Apparatus (Model: HE 158 C)
4
Figure 2a
Temperature profile for a parallel-flow heat exchanger
8
Figure 2b
Temperature profile for a counter-flow heat exchanger
8
Figure 2c
Temperature profile for a 1:2 heat exchanger
8
Figure 3
Single pass flow plate heat exchanger diagram
20
i
List of Tables
Page
Table 1
Valves Arrangement for Flow Selection
5
Table 2
Valves Arrangement for Heat Exchanger Selection
5
ii
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
1.0
INTRODUCTION The SOLTEQ® Heat Exchanger Training Apparatus (Model: HE 158C) has been designed to allow students to get familiarized with different kinds of heat exchangers and to collect the necessary experimental data for the calculation of heat losses, heat transfer coefficient, log mean temperature difference, etc. Students will also be able to study the effect of flow rate on the heat transfer rate. The students may apply this knowledge to complex industrial heat exchangers. The unit comes with four different types of heat exchangers and two stainless steel sump tanks for hot and cold water source. The hot tank is fitted with an 11.5 kW immersion type heater that is protected against possible over heating. Each tank has a centrifugal pump capable of delivering the required 10 LPM of water. The pumps are protected from dry-run by electronic level switches installed. All necessary electronic sensors are fitted at suitable locations for measuring the inlet and outlet temperatures of the hot and cold water, and also the flow rates of the hot and cold water streams. Digital indicators are provided on the control panel for students to read the appropriate data. The unit comes with non-corroding type of piping and fittings including all necessary regulating valves. Upon request, an optional data acquisition system can be provided with the unit which includes personal computer, electronic signal conditioning system, stand alone data acquisition modules and Windows based software for data collection and manipulation. The four heat exchangers supplied with the unit are: a) Shell and Tube Heat Exchanger b) Spiral Heat Exchanger c) Concentric (Double Pipe) Heat Exchanger d) Plate Heat Exchanger
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
2.0
GENERAL DESCRIPTION 2.1
Description and Assembly The SOLTEQ® Heat Exchanger Training Apparatus (Model: HE 158C) consists of mainly the following items. a) Shell & Tube Heat Exchanger Tube O.D. (do) Tube I.D. (di) Tube Length (L) Tube Count (Nt) Tube Pitch (pt) Tube arrangement Shell O.D. Shell I.D. (Ds) Baffle Count Baffle Cut (Bc) Baffle Distance (lB) Material of Construction
: : : : : : : : : : : :
9.53 mm 7.75 mm 500 mm 10 (single pass) 18 mm Triangle 100 mm 85 mm 8 20 % 50 mm 316L Stainless Steel/Borosilicate Glass
b) Spiral Heat Exchanger Coil Tubing O.D. Coil Tubing I.D. Coil Length (L) Shell O.D. Coil I.D. Coil O.D. Shell I.D. (Ds) Material of Construction
: : : : : : : :
9.53 mm 7.05 mm 5.00 m 100 mm 34 mm 44 mm 85 mm 316L Stainless Steel/Borosilicate
c) Concentric (Double Pipe) Heat Exchanger Tube O.D. (do) : 33.40 mm : 26.64 mm Tube I.D. (di) Length (L) : 500 mm Shell O.D. : 100 mm Shell I.D. (Ds) : 85 mm Material of Construction : 316L Stainless Steel/Borosilicate Glass d) Plate Heat Exchanger Nominal Surface Plate Material No.of plates Plate length Plate channel Plate width
: : : : : :
2
0.50 m2 316L stainless steel/copper brazed 4 309.88 mm 43.18 mm 124.46 mm
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
e) Cold Water Circuit Tank : Material : Circulation Pump : Operating Flow rate : f)
Hot Water Circuit Tank : Material : Circulation Pump : Operating Flow rate : Heating System :
50 liter Stainless Steel Centrifugal type 10 LPM (dry-run protected by level switch) 50 liter Stainless Steel Centrifugal type 20 LPM (dry-run protected by level switch) 11.5 kW immersion type heater protected by temperature controller and level switch
g) Instrumentations Measurements of inlet and outlet temperatures for hot water and cold water streams Measurements of flow rates for the hot water and cold water circuits h) Control Panel To mount all the necessary digital indicators, temperature controller and all switches To house electrical components and wirings To house all the necessary data acquisition modules and signal conditioning unit
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
Figure 1: Schematic Diagram for Heat Exchanger Training Apparatus (Model: HE 158 C)
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
2.2
Experimental Capabilities Energy Balance for Heat Exchangers Temperature Profiles in Co-current
2.3
Process Instruments It is important that the user read and fully understand all the instructions and precautions stated in the manufacturer's manuals supplied with the unit prior to operating. The following procedures serve as a quick reference for operating the unit. a) Temperature Controller The first line displays the liquid temperature in the tank while the second line displays the set value. Adjust the set value as follows: Press the ENT button, and then press UP or DOWN arrow key continuously until almost near the desired set value. Press UP or DOWN arrow key one by one until desired set value is reached. Notice that the least digit point is flashing. Press ENT to register the data. Notice that the least digit point goes off. b) Valve Arrangements Table 1: Valves Arrangement for Flow Selection
CoCurrent
OPEN V1, V12, V16, V17, V28
CLOSE V15, V18, V27, V29, V30
LEAVE ALONE V2, V3, V4 - V11, V13, V14, V19 - V26
CounterCurrent
V1, V12, V15, V18, V28
V16, V17, V27, V29, V30
V2, V3, V4 – V11, V13, V14, V19 – V26
Table 2: Valves Arrangement for Heat Exchanger Selection
OPEN Shell & Tube Heat Exchanger Spiral Heat Exchanger Concentric Heat Exchanger Plate Heat Exchanger
V4, V5, V19, V20 V6, V7, V21, V22 V8, V9, V23, V24 V10, V11, V25, V26
CLOSE V6 - V11, V21 - V26 V4, V5, V8 - V11, V19, V20, V23 - V26 V4 - V7, V10, V11, V19 V22, V25, V26 V4 - V9, V19 - V24
Valve V3 : to vary hot water flowrate Valve V14 : to vary cold water flowrate Valve V2 and V13 : Flow bypass for water pump. These valves should be partially opened all the time. If the water flowrates are not stable, reduce the bypass.
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
c) Flow Measurements FT1: Hot water flowrate FT2: Cold water flowrate The flowrates are digitally displayed in LPM. d) Temperature Measurements i)
Counter-Current TT1: Hot water inlet temperature TT2: Hot water outlet temperature TT3: Cold water inlet temperature TT4: Cold water outlet temperature
ii) Co-Current TT1: Hot water inlet temperature TT2: Hot water outlet temperature TT3: Cold water outlet temperature TT4: Cold water inlet temperature e) Operating Limits Temperature 2.4
Overall Dimensions Height : Width : Depth :
2.5
: max. 70 ºC
1.60 m 2.00 m 0.60 m
General Requirements Electrical : Cooling water :
415VAC/50Hz (3 phase) @ 50Amps Laboratory tap water, 20 LPM @ 2 m head Drainage point
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
3.0
INSTALLATIONS AND COMMISIONING 3.1
Installation Procedures 1. The unit must be placed on rigid and level floor that has adequate strength to support its complete weight. 2. Connect the electrical socket 415-VAC/50Hz/3 phase power supply. 3. Connect hoses to the water supply and the drain ports.
3.2
Commissioning Procedures 1. Push the reset button on the Earth Leakage Circuit Breaker (ELCB) inside the control panel after the main power supply is switched on. The ELCB should be kicked off, indicating that the ELCB is functioning properly. If not, get a trained electrician to inspect the electrical connection for any electrical leakage. The ELCB should be tested at least once a month. 2. Ensure that all valves are closed. 3. Fill up water in the tank 1 and tank 2 by opening valves V27 and V28. 4. Switch on the main switch. All indicators should lit-up. 5. Check all temperature readings on the indicators. The measurements should be closed to the surrounding temperature. 6. Switch on the water heater switch on the control panel and set the set point of the temperature controller to 50ºC according to section 2.3 (a). Notice that the water temperature in the hot water tank rises. 7. Set the valves to co-current Shell and Tube Heat Exchanger testing arrangement according to Section 2.3 (b). 8. Switch on the hot and the cold water pump (Pump 1 and Pump 2) and set the flowrates of both streams to 5 LPM by adjusting valves V3 and V14. Check that both pumps are functioning well. 9. Read the water flowrate on the water flow indicators (FT1 and FT2) and check that they are showing the correct readings. 10. Check all pipelines and Shell and tube Heat Exchangers and identify any leakage. Fix the leaking if there is any. Then, proceed to check the other heat exchangers. 11. Use the differential pressure transmitters (high range and low range) located on the bench to measure the pressure drop across the heat exchangers. Read the measurements on the indicators. 12. The unit is now ready for use.
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
SUMMARY OF THEORY 4.1
Shell & Tube Heat Exchanger Most chemical processes involve heat transfer to and from the process fluids. The most commonly used heat-transfer equipment is the shell and tube heat exchanger. If the fluids both flow in the same direction, as shown in Figure 2a, it is referred to as a parallel-flow type; if they flow in the opposite directions, a counterflow type. Fluid Temp.
4.0
T1
T2
T2
ΔT1 t1, mt
t2
t2 t1
Heat Transfered T1, ms
Figure 2a: Temperature profile for a parallel-flow heat exchanger.
Figure 2b: Temperature profile for a counterflow heat exchanger.
Figure 2c: Temperature profile for a 1:2 heat exchanger.
8
ΔT2
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
Heat Balance For a parallel-flow shell and tube heat exchanger with one tube pass and one shell pass shown in Figure 2a, the heat balance is given as: mtCpt (t2 - t1) = msCps(T1 - T2) = q
(1)
Similarly, for the counterflow shell and tube heat exchanger with one tube pass and one shell pass shown in Figure 2b, the heat balance is given as: mtCpt (t2 - t1) = msCps(T1 - T2) = q where,
mt ms Cpt Cps t1, t2 T1, T2 q
= = = = = = =
(2)
mass flowrate of cold fluid in the tube (kgs-1) mass flowrate of hot fluid in the shell (kgs-1) specific heat of cold fluid in the tube (kJkg-1°C-1) specific heat of hot fluid in the shell (kJkg-1°C-1) temperature of cold fluid entering/leaving the tube (°C) temperature of hot fluid entering/leaving the shell (°C) heat exchange rate between fluid (kW)
Heat Transfer The general equation for heat transfer across the tube surface in a shell and tube heat exchanger is given by: q = Uo Ao Tm = Ui AiTm
(3)
where, Ao Ai Tm Uo
= = = =
Ui
=
outside area of the tube (m2) inside area of the tube (m2) mean temperature difference (°C) overall heat transfer coefficient based on the outside area of the tube (kWm-2°C-1) overall heat transfer coefficient based on the inside area of the tube (kWm-2°C-1)
The coefficients Uo and Ui are given by:
1 1 1 d o ln(d o d i ) d o d o Uo ho hod 2k w d i hid d i hi
(4)
and, d d 1 1 1 d i ln(d o d i ) i i U i h i h id 2k w d o hod d o ho
9
(5)
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
where, ho hi hod hid kw do di
= = = = = = =
outside fluid film coefficient (kWm-2°C-1) inside fluid film coefficient (kWm-2°C-1) outside dirt coefficient (fouling factor) (kWm-2°C-1) inside dirt coefficient (kWm-2°C-1) thermal conductivity of the tube wall material (kWm-1°C-1) tube outside diameter (m) tube inside diameter (m)
The mean temperature difference for both parallel and counterflow shell and tube heat exchanger with single shell pass and single tube pass is normally expressed in terms of log-mean temperature difference, Tlm
T1 T2 ln T1 T2
(6)
where, T1 and, T2 are as shown in Fig. 2a and Fig. 2b. For a more complex heat exchanger, such as 1:2 heat exchanger (Fig. 2c), an estimate of the true temperature difference is given by,
Tm = Ft Tlm
(7)
where Ft is the temperature correction factor as a function of two dimensionless temperature ratios R and S:
R
(T1 T2 ) (t t ) and, S 2 1 ( t 2 t1 ) (T1 t1 )
(8)
Having calculated R and S, then Ft is determined from the standard correction factor figures. (Figure C.1 in Appendix C) Tube-side Heat-transfer Coefficient, hi
For turbulent flow, Sieder-Tate equation can be used: Nu C Re 0.8 Pr 0.33 ( f / w ) 0.14 where, Re Nu Pr
= = =
Reynolds Number = f u t d e / f Gt d e / f Nusselt Number = h i d e / k f Prandtl Number = C p f / k f
de
= = =
equivalent (or hydraulic) diameter (m) 4 x (cross-sectional area of flow) / wetted perimeter di for tubes 10
(9)
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
Gt µf µw ρf ut Cp C
= = = = = = = = =
kf
mass velocity, mass flow per unit area (kg/ s.m2) fluid viscosity of bulk fluid temperature (Nsm-2) fluid viscosity at the wall (Nsm-2) fluid density (kgm-3) fluid velocity in tube (ms-1) fluid specific heat, heat capacity (J/kg°C) 0.023 for non-viscous liquids 0.027 for viscous liquids Fluid thermal conductivity (W/m°C)
For laminar flow (Re < 2000), the following correlation is used: Nu 1.86(Re . Pr) 0.33 (d e / L ) 0.33 f w
0.14
where,
(10)
L = the tube length (m)
Tube-side Pressure Drop, Pt
The tube-side pressure drop is given by:
Pt N p 8 j f (L / d i ) w
where,
Pt
= = =
L ut m
= = = =
Np jf
m
2.5
2u f
2 t
(11)
tube-side pressure drop (N/m2) number of tube-side passes tube dimensionless friction factor (Figure C.3 in Appendix C) length of one tube, (m) tube-side velocity (m/s) 0.25 for laminar, Re < 2100 0.14 for turbulent, Re > 2100
Shell-side Heat-transfer Coefficient, hs (Kern’s Method)
In order to determine the heat transfer coefficient for fluid film in shell, first calculate the cross-sectional area of flow As for hypothetical row of tubes of the shell as follows: As ( pt d o )D s l B / pt where,
do pt Ds lB
= = = =
(12)
tube outside diameter (m) tube pitch (m) shell inside diameter (m) distance between baffle (m) 11
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
Then, the shell-side mass velocity, Gs and linear velocity, us are calculated as follows::
where,
Gs us
= =
W s /A s G s /ρ f
Ws ρf
= =
Fluid flowrate on the shell-side (kg/s) shell-side fluid density (kg/m3)
(13) (14)
The shell equivalent diameter, de is given by: de
4 ( p t2 d do
1 . 27 do
p
2 t
2 o
/4)
0 . 785 d
2 o
(15)
(For square pitch arrangement) 1 p 4 t 0.87p t d o2 / 4 2 2 de d o / 2
(16)
1.10 2 p t 0.917d o2 do (For equilateral triangular pitch arrangement)
Thus, Reynolds number in shell is given by: Re
= =
Gs de / µf us de ρ f / µf
(17)
Baffle cut, Bc, is used to specify the dimensions of a segmental baffle. It is the height of the segment removed to form the baffle, expressed as a percentage of the baffle disc diameter. Using this Reynolds number and given Bc value, the heat transfer factor, jh value is determined from Figure C.4. Then, the heat transfer coefficient for fluid film in shell is calculated from: Nu hs d e / k f j h Re Pr 0.33 f w
0.14
12
(18)
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
Shell-side Pressure Drop, Ps (Kern’s Method)
The shell-side pressure drop is given by: Ps 8 j f (D s / d e )(L / l B )
u s2 2
f
w 0.14
(19)
where, ΔPs jf lB us
= = = =
shell pressure drop (N/m2) shell dimensionless friction factor from Figure C.5 distance between baffle (m) shell-side velocity (m/s)
Shell-side Heat-transfer Coefficient, hs (Bell’s Method)
The shell-side heat transfer coefficient is given by: hs hoc Fn Fw Fb FL
where, hoc
=
Fn
=
Fw Fb FL
= = =
(20)
heat transfer coefficient calculated for cross-flow over an ideal tube bank, no leakage or by-passing, correction factor to allow for the effect of the number of vertical tube rows, window effect correction factor, by-pass stream correction factor, leakage correction factor.
The ideal cross-flow heat transfer coefficient hoc is given by, h oc d o j h Re Pr 0.33 ( f w ) 0.14 kf
where, Re = =
(21)
Gs do/ µf us do ρ f / µf
Heat-transfer coefficient for an ideal cross-flow tube banks can be calculated using the heat transfer factors, j h from Figure C.6 in Appendix C. The correction factor Fn is determined as follows: a) For Re > 2000, turbulent, take Fn from Figure C.7 b) For Re > 100 to 2000, transition region, take Fn = 1.0 c) For Re < 100, laminar region, Fn (N c ) 0.18 where N c = numbers of rows crossed in series from end to end of the shell. 13
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
The window correction factor Fw is plotted against Rw as shown in Figure C.8 where Rw is the ratio of the numbers of tubes in the window zones to the total number in the bundle. The by-pass correction factor Fb is,
A 13 (22) Fb exp b 1 2N s / N cv for N s N cv / 2 As where, = 1.5 for laminar flow, Re < 100, = 1.35 for transitional and turbulent flow Re > 100 clearance area between the bundle and the shell Ab = maximum area for cross-flow As = number of sealing strips encountered by the by-pass stream Ns = in the cross-flow zone the number of constrictions, tube rows, encountered in the Ncv = cross-flow section.
If there is no sealing strips used, Fb is obtained from Figure C.9. The leakage correction factor FL is, FL 1 L Atb 2 Asb / AL where
L
= = = =
Atb Asb AL
(23)
a factor obtained from Figure C.10. tube-to-baffle clearance area, per baffle, shell-to-baffle clearance area, per baffle, total leakage area, Atb + Asb
Shell-side Pressure Drop, Ps (Bell’s Method)
The total shell-side pressure drop is the sum of pressure drop in cross-flow and window zones, determined separately. The pressure drop in the cross-flow zones ∆Pc between the baffle tips is calculated from the correlations for ideal tube banks, and corrected for leakage and bypassing.
Pc Pi FbFL
(24)
where,
Pi = = Ncv
=
pressure drop calculated for an equivalent ideal tube bank, u s2 w 0.14 8 j f N cv (25) 2 number of tube rows crossed (in the cross-flow region),
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
us
=
jf Fb FL
= = =
shell-side velocity, based on the clearance area As at the bundle equator, friction factor from Figure C.11 for Re calculated with us by-pass correction factor, leakage correction factor.
Calculate Fb from Equation 21 with = 5.0 for laminar region, Re < 100 and = 4.0 for transition and turbulent region, Re > 100. If no sealing strips used, take Fb from Figure C.12. Calculate FL from Equation 22 taking L from Figure C.13. The window-zone pressure drop is,
Pw FL(2 0.6N wv ) u z2 2
(26)
where, uz
=
geometric mean velocity, =
uw us
uw Ws Nwv
= = =
velocity in the window zone = Ws Aw , shell-side fluid mass flow (kg/s), number of restrictions for cross-flow in window zone, approximately equal to the number of tube rows.
The end-zone pressure drop is,
Pe Pi N wv N cv N cv Fb
(27)
Thus, the total shell-side pressure drop is the sum of pressure drops over all the zones in series from inlet to outlet:
Ps 2(end zones) + (N b 1)(crossflow zones) + N b (window zones) =2Pe (N b 1)Pc N b Pw (28) where, Nb = number of baffles = (L/ lB – 1)
(29)
Shell and Bundle Geometry
The shell and bundle geometry described below shall be used for calculating the correction factors above. where Hc
=
Hb
=
baffle cut height = Bc x Ds, where Bc is the baffle cut as a fraction, height from the baffle chord to the top of the tube bundle, 15
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
Bb b Db
= = =
“bundle cut” = Hb / Db, angle subtended by the baffle chord (rads), bundle diameter
Subsequently, H b Db / 2 Ds (0.5 Bc )
(30)
Ncv (Db 2H b ) / pt
(31)
Nwv H b / pt
(32)
where
pt
= = =
vertical tube pitch, pt for square pitch, 0.87 pt for equilateral triangular pitch.
The number of tubes in a window zone Nw is given by: N w N t Ra
(33)
where Ra can be obtained from Figure C.15, for the appropriate “bundle cut”, Bb. The number of tubes in a cross-flow zone Nc is given by, Nc=Nt – 2 Nw
(34)
and Rw=2 Nw / Nt
(35)
Aw R a ( D s2 4) N w ( d o2 4)
(36)
where Ra is obtained from Figure C.15 for the appropriate baffle cut, Bc. Atb (c t d o 2) (N t N w )
(37)
where ct is the diametrical tube-to-baffle clearance, typically 0.8mm. Asb (c s Ds 2) (2 b )
(38)
where cs is the baffle-to-shell clearance and θb can be obtained from Figure C.15 for the appropriate baffle cut, Bc. Ab=lB (Ds – Db)
(39)
where lB is the baffle spacing.
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
4.2
Spiral Heat Exchanger
A Spiral Heat Exchanger is actually a form of concentric heat exchanger (Please refer to Section 3.3), but coiled in such a way that the effectiveness of the heat transfer is increased. The correlation for forced convective heat transfer in conduits can be used to predict the heat transfer coefficient in the annulus, with the following modification of the equivalent diameter. 4 cross sec tional area wetted perimeter
de =
(40)
2 2 2 4 d 3 d 2 d1 2 2 2 4 = d 3 d 2 d1 = d 3 d 2 d 1 d 3 d 2 d 1 where,
4.3
= = =
d3 d2 d1
Shell Inside Diameter Coil Inside Diameter Coil Outside Diameter
Concentric (Double Pipe) Heat Exchanger
A concentric (double pipe) heat exchanger is actually the simplest form of shell and tube heat exchanger. The correlation for forced convective heat transfer in conduits (Equation 39) can be used to predict the heat transfer coefficient in the annulus, using the appropriate equivalent diameter: de
4 x cross sec tional area wetted perimeter
4 d 22 d12 4 d 2 d1
(41)
d 2 d1
where
d2 d1
= =
inside diameter of the outer pipe outside diameter of the inner pipe
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
4.4
Plate Heat Exchanger
Plate heat exchangers are used extensively in the food and beverage industries due to the fact that they are easily taken apart for cleaning and inspection. Their used in other industries will depend on the relative cost as compared to other types of heat exchanger such as the shell and tube heat exchangers. The general equation for heat transfer across a surface is:
Q = U A Tm where, Q = U = A = Tm =
(42)
heat transfer per unit time, W the overall heat transfer coefficient, W/m2°C heat transfer area, m2. the mean temperature difference, the temperature driving force, °C
For counter-current arrangement, the temperature difference correction factor Ft will be close to 1. Therefore,
Tm = Tlm
(43)
where, Tlm
Tlm T1 T2 t1 t2
= = = = =
T1 t2 T2 t1 T t ln 1 2 T2 t1
(44)
log mean temperature difference inlet hot water temperature outlet hot water temperature inlet cold water temperature outlet cold water temperature
From heat balance, Q = m Cp T
(45)
where, m = mass flowrate of fluid in the plates (kgs-1) Ct = specific heat of fluid in the plates (kJkg-1°C-1) T = temperature difference of fluid entering/leaving the plates (°C) One may use the equation for forced-convective heat transfer in conduits to the plate heat exchangers by applying appropriate constant C and indices a, b, and c. For the purpose of designing the exchanger, a typical equation as given below is useful for making a preliminary estimate of the area required.
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SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
hpd e kf
0.26 Re
0.65
Pr f w 0.4
0.14
(46)
where, hp = plate film coefficient. Gd Re p e
(47)
and Pr
Cp
(48)
kf
where, Gp = = Af = de = = Cp =
mass flow rate per unit cross-sectional area W/Af cross-sectional area for flow equivalent (hydraulic) diameter twice the gap between the plates fluid specific heat, heat capacity
The flow arrangement in a plate heat exchanger is much closer to true countercurrent flow than in a shell and tube heat exchanger. Therefore, the mean temperature difference will generally be higher in a plate heat exchanger. For a series arrangement the logarithmic mean temperature difference correction factor Ft will be close to 1. The plate pressure drop can be estimated using a form of the equation for flow in a conduit: Lp Pp 8 j f de
u p 2
2
(49)
where, Lp = the path length up = Gp/. For preliminary calculations the following relationship can be used for turbulent flow: j f 1.25 Re 0.3
(50)
The transition from laminar to turbulent flow will normally occur at a Reynolds number of 100 to 400, depending on the plate design. With some designs, turbulence can be achieved at very low Reynolds numbers, which makes plate heat exchangers very suitable for use with viscous fluid. 19
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
Figure 3: Single pass flow plate heat exchanger diagram
20
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
5.0
GENERAL OPERATING PROCEDURES 5.1
General Start-up Procedures
1. Perform a quick inspection to make sure that the equipment is in a proper working condition. 2. Be sure that all valves are initially closed, except V1 and V12. 3. Fill up hot water tank via a water supply hose connected to valve V27. Once the tank is full, close the valve. 4. Fill up the cold-water tank by opening valve V 28 and leave the valve opened for continues water supply. 5. Connect a drain hose to the cold water drain point. 6. Switch on main power. Switch on the heater for the hot water tank and set point the temperature controller to 50 C. Note: Recommended maximum temperature controller set point is 70 C 7. Allow the water temperature in the hot water tank to reach the set-point. 8. The equipment is now ready to be run. 5.2
General Shut-down Procedures
1. 2. 3. 4.
Switch off heater. Wait until the hot water temperature drops below 40°C. Switch off pump P1 and pump P2. Switch off main power. Drain off all water in the process lines. Retain water in the hot and cold water tanks for next laboratory session. 5. Close all valves. Note: If the equipment is not to be run for a long period, drain all water completely.
21
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
6.0
EXPERIMENTAL PROCEDURES 6.1
Experiment 1.A: Counter-Current Shell & Tube Heat Exchanger
In this experiment, cold water enters the shell at room temperature while hot water enters the tubes in the opposite direction. Students shall vary the hot water and cold water flow rates and record the inlet and outlet temperatures of both the hot water and cold water streams at steady state. Procedure:
1. Perform general start-up procedures in Section 4.1. 2. Switch the valves to counter-current Shell & Tube Heat Exchanger arrangement (Please refer to Section 2.3). 3. Switch on pumps P1 and P2. 4. Open and adjust valves V3 and V14 to obtain the desired flowrates for hot water and cold water streams, respectively. 5. Allow the system to reach steady state for 10 minutes. 6. Record FT1, FT2, TT1, TT2, TT3 and TT4. 7. Record pressure drop measurements for shell-side and tube-side for pressure drop studies. 8. Repeat steps 4 to 7 for different combinations of flowrate FT1 and FT2 as in the results sheet. 9. Switch off pumps P1 and P2 after the completion of experiment. 10. Proceed to the next experiment or shut-down the equipment. Results:
FT 1 (LPM) 10 10 10 10 10
FT 2 (LPM) 2 4 6 8 10
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
DPT1 (mmH2O)
DPT2 (mmH2O)
FT 1 (LPM) 2 4 6 8 10
FT 2 (LPM) 10 10 10 10 10
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
DPT1 (mmH2O)
DPT2 (mmH2O)
22
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
Assignments:
1. 2. 3. 4. 5.
Calculate the heat transfer and heat loss for energy balance study. Calculate the LMTD. Calculate heat transfer coefficients. Calculate the pressure drop and compare with the experimental result. Perform temperature profile study and the flow rate effects on heat transfer.
23
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
6.2
Experiment 1.B: Co-Current Shell & Tube Heat Exchanger
In this experiment, cold water enters the shell at room temperature while hot water enters the tubes in the same direction. Students shall vary the hot water and cold water flow rates and record the inlet and outlet temperatures of both the hot water and cold water streams at steady state. Procedure:
1. Perform general start-up procedures in Section 4.1. 2. Switch the valves to co-current Shell & Tube Heat Exchanger arrangement (Please refer to Section 2.3). 3. Switch on pumps P1 and P2. 4. If there is air trap in the shell-side, switch the valves to counter-current and bleed the air with high water flowrate. Then switch the valves position back to co-current position. 5. Open and adjust valves V3 and V14 to obtain the desired flowrates for hot water and cold water streams, respectively. 6. Allow the system to reach steady state for 10 minutes. 7. Record FT1, FT2, TT1, TT2, TT3 and TT4. 8. Record pressure drop measurements for shell-side and tube-side for pressure drop studies. 9. Repeat steps 5 to 8 for different combinations of flowrate FT1 and FT2 as in the results sheet. 10. Switch off pumps P1 and P2 after the completion of experiment. 11. Proceed to the next experiment or shut-down the equipment. Results:
FT 1 (LPM) 10 10 10 10 10
FT 2 (LPM) 2 4 6 8 10
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
DPT1 (mmH2O)
DPT2 (mmH2O)
FT 1 (LPM) 2 4 6 8 10
FT 2 (LPM) 10 10 10 10 10
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
DPT1 (mmH2O)
DPT2 (mmH2O)
24
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
Assignments: 1. Calculate the heat transfer and heat loss for energy balance study. 2. Calculate the LMTD. 3. Calculate heat transfer coefficients. 4. Calculate the pressure drop and compare with the experimental result. 5. Perform temperature profile study and the flow rate effects on heat transfer.
25
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
6.3
Experiment 2.A: Counter-Current Spiral Heat Exchanger
In this experiment, cold water enters the shell at room temperature while hot water enters the tubes in the opposite direction. Students shall vary the hot water and cold water flow rates and record accordingly the inlet and outlet temperatures of both the hot water and cold water streams at steady state. Procedure:
1. Perform general start-up procedures in Section 4.1. 2. Switch the valves to counter-current Spiral Heat Exchanger arrangement (Please refer to Section 2.3). 3. Switch on pumps P1 and P2. 4. Open and adjust valves V3 and V14 to obtain the desired flowrates for hot water and cold water streams, respectively. 5. Allow the system to reach steady state for 10 minutes. 6. Record FT1, FT2, TT1, TT2, TT3 and TT4. 7. Record pressure drop measurements for shell-side and tube-side for pressure drop studies. 8. Repeat steps 4 to 7 for different combinations of flowrate FT1 and FT2 as in the results sheet. 9. Switch off pumps P1 and P2 after the completion of experiment. 10. Proceed to the next experiment or shut-down the equipment. Results:
FT 1 (LPM) 5.0 5.0 5.0 5.0
FT 2 (LPM) 2.0 3.0 4.0 5.0
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
FT 1 (LPM) 2.0 3.0 4.0 5.0
FT 2 (LPM) 5.0 5.0 5.0 5.0
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
Assignments: 1. Calculate the heat transfer and heat loss for energy balance study. 2. Calculate the LMTD. 3. Calculate heat transfer coefficients. 4. Perform temperature profile study and the flow rate effects on heat transfer.
26
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
6.4
Experiment 2.B: Co-Current Spiral Heat Exchanger
In this experiment, cold water enters the shell at room temperature while hot water enters the tubes in the same direction. Students shall vary the hot water and cold water flow rates and record accordingly the inlet and outlet temperatures of both the hot water and cold water streams at steady state. Procedure:
1. Perform general start-up procedures in Section 4.1. 2. Switch the valves to co-current Spiral Heat Exchanger arrangement (Please refer to Section 2.3). 3. Switch on pumps P1 and P2. 4. Open and adjust valves V3 and V14 to obtain the desired flowrates for hot water and cold water streams, respectively. 5. Allow the system to reach steady state for 10 minutes. 6. Record FT1, FT2, TT1, TT2, TT3 and TT4. 7. Record pressure drop measurements for shell-side and tube-side for pressure drop studies. 8. Repeat steps 4 to 7 for different combinations of flowrate FT1 and FT2 as in the results sheet. 9. Switch off pumps P1 and P2 after the completion of experiment. 10. Proceed to the next experiment or shut-down the equipment. Results:
FT 1 (LPM) 5.0 5.0 5.0 5.0
FT 2 (LPM) 2.0 3.0 4.0 5.0
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
FT 1 (LPM) 2.0 3.0 4.0 5.0
FT 2 (LPM) 5.0 5.0 5.0 5.0
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
Assignments: 1. Calculate the heat transfer and heat loss for energy balance study. 2. Calculate the LMTD. 3. Calculate heat transfer coefficients. 4. Perform temperature profile study and the flow rate effects on heat transfer.
27
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
6.5
Experiment 3.A: Counter-Current Concentric Heat Exchanger
In this experiment, cold water enters the shell at room temperature while hot water enters the tubes in the opposite direction. Students shall vary the hot water and cold water flow rates and record the inlet and outlet temperatures of both the hot water and cold water streams at steady state. Procedure:
1. Perform general start-up procedures in Section 4.1. 2. Switch the valves to counter-current Concentric Heat Exchanger arrangement (Please refer to Section 2.3). 3. Switch on pumps P1 and P2. 4. Open and adjust valves V3 and V14 to obtain the desired flowrates for hot water and cold water streams, respectively. 5. Allow the system to reach steady state for 10 minutes. 6. Record FT1, FT2, TT1, TT2, TT3 and TT4. 7. Record pressure drop measurements for shell-side and tube-side for pressure drop studies. 8. Repeat steps 4 to 7 for different combinations of flowrate FT1 and FT2 as in the results sheet. 9. Switch off pumps P1 and P2 after the completion of experiment. 10. Proceed to the next experiment or shut-down the equipment. Results:
FT 1 (LPM) 10.0 10.0 10.0 10.0 10.0
FT 2 (LPM) 2.0 4.0 6.0 8.0 10.0
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
FT 1 (LPM)
FT 2 (LPM)
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
2.0 4.0 6.0 8.0 10.0
10.0 10.0 10.0 10.0 10.0
Assignments:
1. 2. 3. 4.
Calculate the heat transfer and heat loss for energy balance study. Calculate the LMTD. Calculate heat transfer coefficients. Perform temperature profile study and the flow rate effects on heat transfer. 28
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
6.6
Experiment 3.B: Co-Current Concentric Heat Exchanger
In this experiment, cold water enters the shell at room temperature while hot water enters the tubes in the same direction. Students shall vary the hot water and cold water flow rates and record the inlet and outlet temperatures of both the hot water and cold water streams at steady state. Procedure:
1. Perform general start-up procedures in Section 4.1. 2. Switch the valves to co-current Concentric Heat Exchanger arrangement (Please refer to Section 2.3). 3. Switch on pumps P1 and P2. 4. Open and adjust valves V3 and V14 to obtain the desired flowrates for hot water and cold water streams, respectively. 5. Allow the system to reach steady state for 10 minutes. 6. Record FT1, FT2, TT1, TT2, TT3 and TT4. 7. Record pressure drop measurements for shell-side and tube-side for pressure drop studies. 8. Repeat steps 4 to 7 for different combinations of flowrate FT1 and FT2 as in the results sheet. 9. Switch off pumps P1 and P2 after the completion of experiment. 10. Proceed to the next experiment or shut-down the equipment. Results:
FT 1 (LPM) 10.0 10.0 10.0 10.0 10.0
FT 2 (LPM) 2.0 4.0 6.0 8.0 10.0
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
FT 1 (LPM) 2.0 4.0 6.0 8.0 10.0
FT 2 (LPM) 10.0 10.0 10.0 10.0 10.0
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
Assignments:
1. 2. 3. 4.
Calculate the heat transfer and heat loss for energy balance study. Calculate the LMTD. Calculate heat transfer coefficients. Perform temperature profile study and the flow rate effects on heat transfer.
29
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
6.7
Experiment 4.A: Counter-Current Plate Heat Exchanger
In this experiment, cold water enters the heat exchanger at room temperature while hot water enters the heat exchanger in the opposite direction. Students shall vary the hot water and cold water flow rates and record the inlet and outlet temperatures of both the hot water and cold water streams at steady state. Procedure:
1. Perform general start-up procedures in Section 4.1. 2. Switch the valves to counter-current Plate Heat Exchanger arrangement (Please refer to Section 2.3). 3. Switch on pumps P1 and P2. 4. Open and adjust valves V3 and V14 to obtain the desired flowrates for hot water and cold water streams, respectively. 5. Allow the system to reach steady state for 10 minutes. 6. Record FT1, FT2, TT1, TT2, TT3 and TT4. 7. Record pressure drop measurements for shell-side and tube-side for pressure drop studies. 8. Repeat steps 4 to 7 for different combinations of flowrate FT1 and FT2 as in the results sheet. 9. Switch off pumps P1 and P2 after the completion of experiment. 10. Proceed to the next experiment or shut-down the equipment. Results:
FT 1 (LPM) 8.0 8.0 8.0 8.0 8.0
FT 2 (LPM) 2.0 4.0 6.0 8.0 10.0
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
FT 1 (LPM) 2.0 4.0 6.0 8.0 10.0
FT 2 (LPM) 8.0 8.0 8.0 8.0 8.0
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
Assignments:
1. 2. 3. 4.
Calculate the heat transfer and heat loss for energy balance study. Calculate the LMTD. Calculate heat transfer coefficients. Perform temperature profile study and the flow rate effects on heat transfer. 30
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
6.8
Experiment 4.B: Co-Current Plate Heat Exchanger
In this experiment, cold water enters the heat exchanger at room temperature while hot water enters in the same direction. Students shall vary the hot water and cold water flow rates and record accordingly the inlet and outlet temperatures of both the hot water and cold water streams at steady state. Procedure: 1. Perform general start-up procedures in Section 4.1. 2. Switch the valves to co-current Plate Heat Exchanger arrangement (Please refer to Section 2.3). 3. Switch on pumps P1 and P2. 4. Open and adjust valves V3 and V14 to obtain the desired flowrates for hot water and cold water streams, respectively. 5. Allow the system to reach steady state for 10 minutes. 6. Record FT1, FT2, TT1, TT2, TT3 and TT4. 7. Record pressure drop measurements for shell-side and tube-side for pressure drop studies. 8. Repeat steps 4 to 7 for different combinations of flowrate FT1 and FT2 as in the results sheet. 9. Switch off pumps P1 and P2 after the completion of experiment. 10. Proceed to the next experiment or shut-down the equipment. Results:
FT 1 (LPM) 7.5 7.5 7.5 7.5 7.5
FT 2 (LPM) 2.0 4.0 6.0 8.0 9.5
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
FT 1 (LPM)
FT 2 (LPM)
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
7.5 7.5 7.5 7.5 7.5
2.0 4.0 6.0 8.0 9.5
Assignments:
1. 2. 3. 4.
Calculate the heat transfer and heat loss for energy balance study. Calculate the LMTD. Calculate heat transfer coefficients. Perform temperature profile study and the flow rate effects on heat transfer. 31
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
7.0
EQUIPMENT MAINTENANCE
1. Restore the system to operating conditions after any repair job. 2. Only properly trained personnel shall be allowed to carry out any servicing. 3. Before servicing, shut down the whole operation and let the system to cool down.
8.0
SAFETY PRECAUTION
1. The unit must be operated under the supervision of trained personnel. 2. All operating instructions supplied with the unit must be read and understood before attempting to operate the unit. 3. Always check and rectify any leak. 4. Always make sure that the heater is fully immersed in the water. 5. Do not touch the hot components of the unit. 6. Be extremely careful when handling liquid at high temperature. 7. Always switch off the heater and allow the liquid to cool down before draining.
32
SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________
9.0
REFERENCES
Chopey, N.P. “Handbook of Chemical Engineering Calculations (2nd Edition)”, McGraw-Hill, 1994. Coulson, J.M. and Richardson, J.F. “Chemical Engineering, Volume 1 (3rd Edition)”, Pergamon Press, 1977. Coulson, J.M. and Richardson, J.F. “Chemical Engineering, Volume 6 (Revised 3rd Edition)”, Butterworth-Heinemann, 1996. Kern, D.Q. “Process Heat Transfer (Int’l Edition)”, McGraw-Hill, 1965. Perry, R.H., Green, D.W. and Maloney, J.O. “Perry’s Chemical Engineering Handbook (6th Edition)”, McGraw-Hill, 1984.
33
APPENDIX A EXPERIMENTAL DATA SHEETS
Experiment 1.A: Co-Current Shell & Tube Heat Exchanger
FI 1 (LPM)
FI 2 (LPM)
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
DPT1 (mmH2O)
DPT2 (mmH2O)
Experiment 1.B: Counter-Current Shell & Tube Heat Exchanger
FI 1 (LPM)
FI 2 (LPM)
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
DPT1 (mmH2O)
DPT2 (mmH2O)
Experiment 2.A: Co-Current Helical Coil Heat Exchanger
FI 1 (LPM)
FI 2 (LPM)
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
TT 3 (°C)
TT 4 (°C)
Experiment 2.B: Counter-Current Helical Coil Heat Exchanger
FI 1 (LPM)
FI 2 (LPM)
TT 1 (°C)
TT 2 (°C)
Experiment 3.A: Co-Current Concentric Heat Exchanger
FI 1 (LPM)
FI 2 (LPM)
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
TT 3 (°C)
TT 4 (°C)
Experiment 3.B: Counter-Current Concentric Heat Exchanger
FI 1 (LPM)
FI 2 (LPM)
TT 1 (°C)
TT 2 (°C)
Experiment 4.A: Co-Current Plate Heat Exchanger
FI 1 (LPM)
FI 2 (LPM)
TT 1 (°C)
TT 2 (°C)
TT 3 (°C)
TT 4 (°C)
TT 3 (°C)
TT 4 (°C)
Experiment 4.B: Counter-Current Plate Heat Exchanger
FI 1 (LPM)
FI 2 (LPM)
TT 1 (°C)
TT 2 (°C)
APPENDIX B CONVERSION FACTORS
Table B.1: Conversion Factors for Single Terms
To convert from
To
Multiply by
Btu (thermochemical) Calorie (thermochemical) Foot lbf Foot poundal Kilowatt hour Watt hour
Energy Joule Joule Joule Joule Joule Joule
1054.35026448 4.184 1.3558179 0.042140110 3.6 x 106 3600
Dyne Kilogram force (kgf) Ounce force (avoirdupois) Pound force, lbf (avoirdupois) Poundal
Force Newton Newton Newton Newton Newton
1.0 x 10-5 9.80665 0.27801385 4.44822161526 0.1382549543
Angstrom Foot Inch Micron Mil Mile (U.S state) Yard
Length Meter Meter Meter Meter Meter Meter Meter
1.0 x 10-10 0.3048 0.0254 1.0 x 10-6 2.54 x 10-5 1609.344 0.9144
Gram Kgf second2 meter Lbm (avoirdupois) Ounce mass (avoirdupois) Ton (long) Ton (metric) Ton (short, 2000 pound)
Mass Kilogram Kilogram Kilogram Kilogram Kilogram Kilogram Kilogram
1.0 x 10-3 9.80665 0.45359237 0.028349523 1016.0469 1000 907.18474
Celcius Fahrenheit
Temperature Kelvin Celcius
Fahrenheit
Kelvin
Kelvin
Celcius
Rankine
Kelvin
K = C + 273.15 5 C = ( F – 32 ) 9 5 C = ( F – 459.67 ) 9 5 C= F – 273.15 9 5 C= R 9
Table B.2: Conversion Factors for Compound Terms
To convert from
To
Multiply by
Foot/ second2 Inch/second2
Acceleration Meter/ second2 Meter/ second2
0.3048 0.0254
Gram/ centimeter Lbm/ foot3 Slug/ foot3
Density Kilogram/ meter3 Kilogram/ meter3 Kilogram/ meter3
1000 16.018463 515.379
Btu/ foot2 – hour *Calories/ second Watt/ centimeter2
Energy/ Area-Time Watt/ meter3 Watt/ meter3 Watt/ meter3
3.1524808 697.33333 10000
Btu/ second Calories/ second Foot lbf/ second horsepower (5550 ft lbf/ second) horsepower (electric) horsepower (metric)
Power Watt Watt Watt Watt Watt Watt
1054.3502644 4.184 1.3558179 745.69987 746.00 735.499
Atmosphere Bar Milimeter of mercury (0ºC) Centimeter of water (4ºC) Dyne/ centimeter2 Kgf/ centimeter2 Lbf/ inch2 (psi) Pascal Torr (0ºC)
Pressure Newton/ meter2 Newton/ meter2 Newton/ meter2 Newton/ meter2 Newton/ meter2 Newton/ meter2 Newton/ meter2 Newton/ meter2 Newton/ meter2
1.01325 x 105 1.0 x 105 133.322 98.0638 0.100 98066.5 6894.7572 1.00 133.322
Foot/ second Kilometer/ hour Knot (international) Mile/ hour (U.S state)
Speed Meter/ second Meter/ second Meter/ second Meter/ second
0.3048 0.27777778 0.51444444 0.44704
Btu inch/ foot2 Second-ºF Btu/ food-hour ºF
Thermal Conductivity Joule/ meter-second-K Joule/ meter-second-K
518.87315 1.7295771
Table B.3: Conversion Factors for Compound Terms (Continued)
To convert from
To
Multiply by
Centipoises Centistoke Foot2/ second Lbm/ food-second Lbf second/ foot2 Poise Poundal second/ ft2 Slug/ foot-second Stoke
Viscosity Newton second/ meter2 Meter2/ second Meter2/ second Newton second/ meter2 Newton second/ meter2 Newton second/ meter2 Newton second/ meter2 Newton second/ meter2 Meter2/ second
1.0 x 10-3 1.0 x 10-6 0.09290304 1.4881639 47.880258 0.10 1.4881639 47.880258 1.0 x 10-4
Fluid ounce (U.S) Foot3 Gallon (British) Gallon (U.S dry) Gallon (U.S liquid) Liquid (H2O at 4ºC) Liter (SI) Pint (U.S liquid) Quart (U.S liquid) Yard3
Volume Meter3 Meter3 Meter3 Meter3 Meter3 Meter3 Meter3 Meter3 Meter3 Meter3
2.95735295 x 10-5 0.0283168465 4.546087 x 10-3 4.40488377 x 10-3 3.78541178 x 10-3 1.000028 x 10-3 1.0 x 10-3 4.73176473 x 10-4 9.4635295 x 10-4 0.764554857
Table B.4: Heat Transfer Properties of Liquid Water, SI Units
T (ºC)
T (K)
ρ (kg/m3)
cp (kJ/kg.K)
k (W/m.K)
NPr
0.0
273.2
999.6
4.229
0.5694
13.3
μ x 103 (Pa.s) 1.786
15.6
288.8
998.0
4.187
0.5884
8.07
1.131
26.7
299.9
996.4
4.183
0.6109
5.89
0.860
37.8
311.0
994.7
4.183
0.6283
4.51
0.682
65.6
338.8
981.9
4.187
0.6629
2.72
0.432
93.3
366.5
962.7
4.229
0.6802
1.91
0.3066
121.1
394.3
943.5
4.271
0.6836
1.49
0.2381
148.9
422.1
917.9
4.312
0.6836
1.22
0.1935
204.4
477.6
858.6
4.522
0.6611
0.950
0.1384
260.0
533.2
784.9
4.982
0.6040
0.859
0.1042
315.6
588.8
679.2
6.322
0.5071
1.07
0.0862
APPENDIX C HEAT EXCHANGER CALCULATION DATA
Figure C.1: Temperature correction factor: one shell pass; two or more even tube passes
Figure C.2: Tube side heat transfer factors
Figure C.3: Tube side friction factors.
Figure C.4: Shell side heat transfer factors, segmental baffles.
Figure C.5: Shell side friction factors, segmental baffles.
Figure C.6: Heat transfer factors for cross-flow tube banks.
Figure C.7: Tube row correction factor, Fn
Figure C.8: Window correction factor, Fw
Figure C.9: Bypass correction factor, Fb.
Figure C.10: Coefficient for FL, heat transfer.
Figure C.11: Friction factors for cross-flow tube banks.
Figure C.12: Bypass factor for pressure drop, F’b.
Figure C.13: Coefficient for F’L, pressure drop.
Figure C.14: Baffle and tube geometry
Figure C.15: Baffle geometrical factors
APPENDIX D RESULTS SUMMARY
Experiment 1.A: Counter-Current Shell & Tube Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density:
988.18
Heat capacity:
4175.00
Thermal cond:
0.6436
Viscosity:
kg/m
3
J/kg.K W/m.K
0.0005494
Pa.s
995.67
kg/m
Cold water Density: Heat capacity:
4183.00
Thermal cond:
0.6155
Viscosity:
0.0008007
3
J/kg.K W/m.K Pa.s
CALCULATIONS FOR SHELL AND TUBE (Counter-Current) Fixed Hot water flow rate at 10 LPM TEST 1
TEST 2
TEST 3
TEST 4
TEST 5
Hot fluid (Tube): Water Volumetric flowrate
L/min
Mass flow
kg/s
10.0
10.0
10.0
9.9
9.8
0.1647
0.1647
0.1647
0.1630
0.1614
Inlet temp
o
50.8
50.8
51.0
51.4
51.2
Outlet temp
o
C
48.6
47.9
47.6
47.4
47.1
Heat transfer rate
J/s
1512.74
1994.06
2337.87
2722.93
2762.81
Pressure drop
mmH2O
420.00
420.00
412.00
407.00
388.00
C
Cold fluid (Shell): Water Volumetric flowrate
L/min
Mass flow
kg/s
2.0
3.8
5.6
7.3
9.1
0.0332
0.0631
0.0929
0.1211
0.1510
Inlet temp
o
31.2
30.4
30.3
30.2
30.2
Outlet temp
o
C
40.7
37.3
35.8
34.9
34.3
Heat transfer rate
J/s
1318.88
1820.06
2137.98
2381.62
2589.87
Pressure drop
mmH2O
35.50
116.30
238.40
400.20
over
C
Temp difference Hot side inlet T, T1
o
50.8
50.8
51
51.4
51.2
Hot side outlet T, T2
o
48.6
47.9
47.6
47.4
47.1
Cold side inlet T, t1
o
31.2
30.4
30.3
30.2
30.2
Cold side outlet T, t2
o
40.7
37.3
35.8
34.9
34.3
T log mean, Tlm
o
C
13.42
15.41
16.23
16.85
16.00
Heat Loss
W
193.86
174.01
199.89
341.31
172.95
Efficiency
%
87.18
91.27
91.45
87.47
93.74
C C C C
Overall heat transfer coeff 2
Total exchange area
m
Overall heat transfer coeff
W/m .K
2
0.15
0.15
0.15
0.15
0.15
752.97
864.22
962.41
1079.66
1153.50
Exchanger layout Tube
1
1
1
1
1
Shell
1
1
1
1
1
Length of tubes
m
0.5
0.5
0.5
0.5
0.5
Tube ID
mm
7.75
7.75
7.75
7.75
7.75
Tube OD
mm
9.53
9.53
9.53
9.53
9.53
Tube pitch
mm
18
18
18
18
18
Tube surface area
m
2
0.0150
0.0150
0.0150
0.0150
0.0150
10
10
10
10
10
Shell diameter
mm
85
85
85
85
85
Baffle distance
mm
50
50
50
50
50
2
4.72E-05
4.72E-05
4.72E-05
4.72E-05
4.72E-05
10
10
10
10
10
4.72E-04
4.72E-04
4.72E-04
4.72E-04
4.72E-04
Number of tubes
Tube side Cross section area
m
Number of tubes Total cross section area
m
2
2
Mass velocity
kg/m .s
349.13
349.13
349.13
345.64
342.15
Linear velocity
m/s
0.3533
0.3533
0.3533
0.3498
0.3462
4924.98
4924.98
4924.98
4875.73
4826.48
3.56
3.56
3.56
3.56
3.56
turbulent
turbulent
turbulent
turbulent
turbulent
Reynolds Prandtl Type of flow L/ID Heat transfer factor, jh Tube coeff, hi
2
W/m .K
64.52
64.52
64.52
64.52
64.52
3.90E-03
3.90E-03
3.90E-03
3.90E-03
3.90E-03
2426.16
2426.16
2426.16
2401.90
2377.64 2.00E-03
Shell side 2
Cross flow area
m
2.00E-03
2.00E-03
2.00E-03
2.00E-03
Mass velocity
kg/m .s
16.60
31.53
46.47
60.57
75.51
Linear velocity
m/s
0.0167
0.0317
0.0467
0.0608
0.0758
Equivalent diameter
mm
2
Reynolds Prandtl Type of flow Baffle cut
%
Heat transfer factor, jh Shell coeff, hs
2
W/m .K
27.78
27.78
27.78
27.78
27.78
575.88
1094.17
1612.46
2101.96
2620.25
5.44
5.44
5.44
5.44
5.44
laminar
laminar
laminar
turbulent
turbulent
20
20
20
20
20
2.30E-02
1.80E-02
1.60E-02
1.40E-02
1.20E-02
513.18
763.08
999.59
1140.16
1218.25
Pressure drops across heat exchanger Tube-side friction factor, jf
5.80E-03
5.80E-03
5.80E-03
5.80E-03
5.80E-03
Shell-side friction factor, jf
9.80E-02
8.60E-02
7.50E-02
7.20E-02
7.00E-02
Tube-side pressure drop, Dptube (Pa)
338.8
338.8
338.8
332.1
325.4
Tube-side pressure drop, DPtube (mmH2O)
33.4
33.4
33.4
32.8
32.1
Shell-side pressure drop, DPshell (Pa)
3.3
10.5
19.9
32.5
49.1
Shell-side pressure drop, DPshell (mmH2O)
0.3
1.0
2.0
3.2
4.8
Experiment 1.B: Co-Current Shell & Tube Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density:
988.18
Heat capacity:
4175.00
Thermal cond:
0.6436
Viscosity:
kg/m
3
J/kg.K W/m.K
0.0005494
Pa.s
995.67
kg/m
Cold water Density: Heat capacity:
4183.00
Thermal cond:
0.6155
Viscosity:
0.0008007
3
J/kg.K W/m.K Pa.s
CALCULATIONS FOR SHELL AND TUBE (Co-Current) Fixed Hot water flow rate at 10 LPM TEST 1
TEST 2
TEST 3
TEST 4
TEST 5
Hot fluid (Tube): Water Volumetric flowrate
L/min
Mass flow
kg/s
9.9
9.9
9.9
9.9
10.1
0.1630
0.1630
0.1630
0.1630
0.1663
Inlet temp
o
51.1
51.1
51.3
51.2
51.2
Outlet temp
o
C
49.0
48.2
47.8
47.2
46.9
Heat transfer rate
J/s
1429.54
1974.12
2382.56
2722.93
2986.28
Pressure drop
mmH2O
405.00
405.00
408.00
406.00
402.00
C
Cold fluid (Shell): Water Volumetric flowrate
L/min
Mass flow
kg/s
2.0
3.8
5.6
7.5
9.2
0.0332
0.0631
0.0929
0.1245
0.1527
Inlet temp
o
31.6
30.8
30.4
30.3
30.4
Outlet temp
o
C
40.2
36.8
35.4
34.5
34.1
Heat transfer rate
J/s
1193.93
1582.66
1943.61
2186.57
2362.88
Pressure drop
mmH2O
35.40
117.00
233.00
411.30
over 51.2
C
Temp difference Hot side inlet T, T1
o
51.1
51.1
51.3
51.2
Hot side outlet T, T2
o
49
48.2
47.8
47.2
46.9
Cold side inlet T, t1
o
31.6
30.8
30.4
30.3
30.4
Cold side outlet T, t2
o
40.2
36.8
35.4
34.5
34.1
T log mean, Tlm
o
C
13.45
15.42
16.28
16.46
16.48
Heat Loss
W
235.60
391.47
438.95
536.36
623.40
Efficiency
%
83.52
80.17
81.58
80.30
79.12
C C C C
Overall heat transfer coeff 2
Total exchange area
m
Overall heat transfer coeff
W/m .K
2
0.15
0.15
0.15
0.15
0.15
710.11
854.97
977.52
1105.01
1210.67
Exchanger layout Tube
1
1
1
1
1
Shell
1
1
1
1
1
Length of tubes
m
0.5
0.5
0.5
0.5
0.5
Tube ID
mm
7.75
7.75
7.75
7.75
7.75
Tube OD
mm
9.53
9.53
9.53
9.53
9.53
Tube pitch
mm
18
18
18
18
18
Tube surface area
m
2
0.0150
0.0150
0.0150
0.0150
0.0150
10
10
10
10
10
Shell diameter
mm
85
85
85
85
85
Baffle distance
mm
50
50
50
50
50
2
4.72E-05
4.72E-05
4.72E-05
4.72E-05
4.72E-05
10
10
10
10
10
4.72E-04
4.72E-04
4.72E-04
4.72E-04
4.72E-04
Number of tubes
Tube side Cross section area
m
Number of tubes Total cross section area
m
2
2
Mass velocity
kg/m .s
345.64
345.64
345.64
345.64
352.62
Linear velocity
m/s
0.3498
0.3498
0.3498
0.3498
0.3568
4875.73
4875.73
4875.73
4875.73
4974.23
3.56
3.56
3.56
3.56
3.56
turbulent
turbulent
turbulent
turbulent
turbulent
Reynolds Prandtl Type of flow L/ID Heat transfer factor, jh Tube coeff, hi
2
W/m .K
64.52
64.52
64.52
64.52
64.52
3.90E-03
3.90E-03
3.90E-03
3.90E-03
3.90E-03
2401.90
2401.90
2401.90
2401.90
2450.43 2.00E-03
Shell side 2
Cross flow area
m
2.00E-03
2.00E-03
2.00E-03
2.00E-03
Mass velocity
kg/m .s
16.60
31.53
46.47
62.23
76.34
Linear velocity
m/s
0.0167
0.0317
0.0467
0.0625
0.0767
Equivalent diameter
mm
2
Reynolds Prandtl Type of flow Baffle cut
%
Heat transfer factor, jh Shell coeff, hs
2
W/m .K
27.78
27.78
27.78
27.78
27.78
575.88
1094.17
1612.46
2159.55
2649.04
5.44
5.44
5.44
5.44
5.44
laminar
laminar
laminar
turbulent
turbulent
20
20
20
20
20
2.40E-02
1.80E-02
1.60E-02
1.50E-02
1.30E-02
535.49
763.08
999.59
1255.06
1334.27
Pressure drops across heat exchanger Tube-side friction factor, jf
5.80E-03
5.80E-03
5.80E-03
5.80E-03
5.80E-03
Shell-side friction factor, jf
9.20E-02
8.20E-02
7.50E-02
7.20E-02
7.00E-02
Tube-side pressure drop, Dptube (Pa)
332.1
332.1
332.1
332.1
345.6
Tube-side pressure drop, DPtube (mmH2O)
32.8
32.8
32.8
32.8
34.1
Shell-side pressure drop, DPshell (Pa)
3.1
10.0
19.9
34.3
50.1
Shell-side pressure drop, DPshell (mmH2O)
0.3
1.0
2.0
3.4
4.9
Experiment 2.A: Counter-Current Spiral Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density:
988.18
Heat capacity:
4175.00
Thermal cond:
0.6436
Viscosity:
kg/m
3
J/kg.K W/m.K
0.0005494
Pa.s
995.67
kg/m
Cold water Density: Heat capacity:
4183.00
Thermal cond:
0.6155
Viscosity:
0.0008007
3
J/kg.K W/m.K Pa.s
CALCULATIONS FOR SPIRAL HEAT EXCHANGER (Counter-Current) Fixed Hot water flow rate at 5 LPM TEST 1
TEST 2
TEST 3
TEST 4
Hot fluid (Tube): Water Volumetric flowrate
L/min
Mass flow
kg/s
4.90
4.90
4.90
4.90
8.07E-02
8.07E-02
8.07E-02
8.07E-02
Inlet temp
o
51.00
51.00
51.10
51.10
Outlet temp
o
C
47.90
47.60
47.50
47.10
Heat transfer rate
J/s
1044.48
1145.56
1212.94
1347.71
C
Cold fluid (Shell): Water Volumetric flowrate
L/min
2.10
3.00
3.70
4.70
Mass flow
kg/s
0.03
0.05
0.06
0.08
Inlet temp
o
31.10
30.90
30.60
30.60
Outlet temp
o
C
37.60
35.80
34.90
34.20
heat transfer rate
J/s
947.51
1020.40
1104.39
1174.50
C
Temp difference Hot side inlet T, T1
o
51.00
51.00
51.10
51.10
Hot side outlet T, T2
o
47.90
47.60
47.50
47.10
Cold side inlet T, t1
o
31.10
30.90
30.60
30.60
Cold side outlet T, t2
o
37.60
35.80
34.90
34.20
T log mean, Tlm
o
C
15.04
15.94
16.55
16.70
Heat Loss
W
96.97
125.16
108.55
173.21
Efficiency
%
90.72
89.07
91.05
87.15
C C C C
Overall heat transfer coeff 2
Total exchange area
m
Overall heat transfer coeff
W/m .K
0.15
0.15
0.15
0.15
420.96
427.68
445.84
469.83
Coil
1.00
1.00
1.00
1.00
Shell
1.00
1.00
1.00
1.00
2
Exchanger layout
Length of tubes
m
5.00
5.00
5.00
5.00
Tube ID
mm
7.05
7.05
7.05
7.05
Tube OD
mm
9.53
9.53
9.53
9.53
Coil surface area
m
2
0.15
0.15
0.15
0.15
Shell diameter
mm
85.00
85.00
85.00
85.00
Coil ID
mm
34.00
34.00
34.00
34.00
Coil OD
mm
44.00
44.00
44.00
44.00
3.90E-05
3.90E-05
3.90E-05
3.90E-05
2067.34
2067.34
2067.34
2067.34
2.09
2.09
2.09
2.09
26528.53
26528.53
26528.53
26528.53
Tube side 2
Cross section area
m
Mass velocity
kg/m .s
Linear velocity
m/s
Reynolds Prandtl Type of flow
2
3.56
3.56
3.56
3.56
turbulent
turbulent
turbulent
turbulent
TEST 5
Tube coeff, hi
2
11047.45 0.01
0.01
0.01
0.01
2
6.88
9.83
12.13
15.41 0.01548
W/m .K
11047.45
11047.45
11047.45
Shell side 2
Cross flow area
m
Mass velocity
kg/m .s
Linear velocity
m/s
0.00691
0.00988
0.01218
Equivalent diameter
mm
39.54
39.54
39.54
39.54
339.97
485.67
598.99
760.88
Reynolds Prandtl Type of flow
5.44
5.44
5.44
5.44
laminar
laminar
laminar
laminar
Nusselt Number
4.26
5.67
6.71
8.12
Stanton Number
0.00230
0.00215
0.00206
0.00196
0.00717
0.00668
0.00640
0.00610
66.35
88.26
104.39
126.40
Heat transfer factor, jh Shell coeff, hs
2
W/m .K
Experiment 2.B: Co-Current Spiral Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density:
988.18
Heat capacity:
4175.00
Thermal cond:
0.6436
Viscosity:
kg/m
3
J/kg.K W/m.K
0.0005494
Pa.s
995.67
kg/m
Cold water Density: Heat capacity:
4183.00
Thermal cond:
0.6155
Viscosity:
0.0008007
3
J/kg.K W/m.K Pa.s
CALCULATIONS FOR SPIRAL HEAT EXCHANGER (Co-Current) Fixed Hot water flow rate at 5 LPM TEST 1
TEST 2
TEST 3
TEST 4
Hot fluid (Tube): Water Volumetric flowrate
L/min
5.00
5.00
5.00
5.00
Mass flow
kg/s
0.08
0.08
0.08
0.08
Inlet temp
o
51.10
51.10
51.00
51.10
Outlet temp
o
C
48.20
47.50
47.00
46.90
Heat transfer rate
J/s
997.03
1237.70
1375.22
1443.98
C
Cold fluid (Shell): Water Volumetric flowrate
L/min
2.00
2.80
3.80
4.80
Mass flow
kg/s
0.03
0.05
0.06
0.08
Inlet temp
o
32.30
31.90
31.80
31.60
Outlet temp
o
C
38.00
36.70
36.00
35.10
heat transfer rate
J/s
791.33
932.93
1107.86
1166.17
C
Temp difference Hot side inlet T, T1
o
51.10
51.10
51.00
51.10
Hot side outlet T, T2
o
48.20
47.50
47.00
46.90
Cold side inlet T, t1
o
32.30
31.90
31.80
31.60
Cold side outlet T, t2
o
38.00
36.70
36.00
35.10
T log mean, Tlm
o
C
14.06
14.60
14.72
15.33
Heat Loss
W
205.70
304.76
267.36
277.81
Efficiency
%
79.37
75.38
80.56
80.76
C C C C
Overall heat transfer coeff 2
Total exchange area
m
Overall heat transfer coeff
W/m .K
0.15
0.15
0.15
0.15
375.85
426.88
502.72
508.20
Coil
1.00
1.00
1.00
1.00
Shell
1.00
1.00
1.00
1.00
2
Exchanger layout
Length of tubes
m
5.00
5.00
5.00
5.00
Tube ID
mm
7.05
7.05
7.05
7.05
Tube OD
mm
9.53
9.53
9.53
9.53
Coil surface area
m
2
0.15
0.15
0.15
0.15
Shell diameter
mm
85.00
85.00
85.00
85.00
Coil ID
mm
34.00
34.00
34.00
34.00
Coil OD
mm
44.00
44.00
44.00
44.00
Tube side 2
Cross section area
m
Mass velocity
kg/m .s
Linear velocity
m/s
Reynolds Prandtl Type of flow
2
0.00
0.00
0.00
0.00
2109.53
2109.53
2109.53
2109.53
2.13
2.13
2.13
2.13
27069.93
27069.93
27069.93
27069.93
3.56
3.56
3.56
3.56
turbulent
turbulent
turbulent
turbulent
TEST 5
Tube coeff, hi
2
11227.45 0.01
0.01
0.01
0.01
2
6.56
9.18
12.46
15.74
W/m .K
11227.45
11227.45
11227.45
Shell side 2
Cross flow area
m
Mass velocity
kg/m .s
Linear velocity
m/s
0.01
0.01
0.01
0.02
Equivalent diameter
mm
39.54
39.54
39.54
39.54
323.78
453.29
615.18
777.07
5.44
5.44
5.44
5.44
laminar
laminar
laminar
laminar
Nusselt Number
4.10
5.37
6.85
8.26
Stanton Number
0.00
0.00
0.00
0.00
Heat transfer factor, jh
0.01
0.01
0.01
0.01
63.81
83.52
106.64
128.55
Reynolds Prandtl Type of flow
Shell coeff, hs
2
W/m .K
Experiment 3.A: Counter-Current Concentric Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density:
988.18
Heat capacity:
4175.00
Thermal cond:
0.6436
Viscosity:
kg/m
3
J/kg.K W/m.K
0.0005494
Pa.s
995.67
kg/m
Cold water Density: Heat capacity:
4183.00
Thermal cond:
0.6155
Viscosity:
0.0008007
3
J/kg.K W/m.K Pa.s
CALCULATIONS FOR CONCENTRIC HEAT EXCHANGER (Counter-Current) Fixed Hot water flow rate at 10 LPM TEST 1
TEST 2
TEST 3
TEST 4
TEST 5
Hot fluid (Tube): Water Volumetric flowrate
L/min
Mass flow
kg/s
9.70
9.60
9.60
9.70
9.70
0.15976
0.15811
0.15811
0.15976
0.15976
Inlet temp
o
51.10
51.10
51.10
51.10
51.10
Outlet temp
o
C
50.00
49.90
49.80
49.70
49.70
Heat transfer rate
J/s
733.68
792.13
858.14
933.77
933.77
C
Cold fluid (Shell): Water Volumetric flowrate
L/min
Mass flow
kg/s
2.00
3.70
5.40
7.20
8.90
0.03319
0.06140
0.08961
0.11948
0.14769
Inlet temp
o
32.70
31.90
31.70
31.40
31.40
Outlet temp
o
C
35.30
33.70
33.20
32.70
32.60
Heat transfer rate
J/s
360.96
462.30
562.26
649.72
741.35
C
Temp difference Hot side inlet T, T1
o
51.10
51.10
51.10
51.10
51.10
Hot side outlet T, T2
o
50.00
49.90
49.80
49.70
49.70
Cold side inlet T, t1
o
32.70
31.90
31.70
31.40
31.40
Cold side outlet T, t2
o
35.30
33.70
33.20
32.70
32.60
T log mean, Tlm
o
C
16.54
17.70
18.00
18.35
18.40
Heat Loss
W
372.72
329.82
295.88
284.05
192.42
Efficiency
%
49.20
58.36
65.52
69.58
79.39
C C C C
Overall heat transfer coeff 2
Total exchange area
m
Overall heat transfer coeff
W/m .K
2
0.05
0.05
0.05
0.05
0.05
845.55
853.09
908.70
969.93
967.30
Exchanger layout Tube
1.00
1.00
1.00
1.00
1.00
Shell
1.00
1.00
1.00
1.00
1.00
Length of tubes
m
0.50
0.50
0.50
0.50
0.50
Tube ID
mm
26.64
26.64
26.64
26.64
26.64
Tube OD
mm
33.40
33.40
33.40
33.40
33.40
Tube surface area
m
2
0.05
0.05
0.05
0.05
0.05
Shell diameter
mm
85.00
85.00
85.00
85.00
85.00 0.000557
Tube side 2
Cross section area
m
0.000557
0.000557
0.000557
0.000557
Mass velocity
kg/m .s
286.61
283.66
283.66
286.61
286.61
Linear velocity
m/s
0.29004
0.28705
0.28705
0.29004
0.29004 13897.73
Reynolds
2
13897.73
13754.45
13754.45
13897.73
Prandtl
3.56
3.56
3.56
3.56
3.56
Nuselt number
72.15
71.55
71.55
72.15
72.15
Type of flow
turbulent
turbulent
turbulent
turbulent
turbulent
Stanton Number
0.00146
0.00146
0.00146
0.00146
0.00146
Heat transfer factor, jh Tube coeff, hi
2
W/m .K
0.00341
0.00342
0.00342
0.00341
0.00341
1743.02
1728.63
1728.63
1743.02
1743.02 0.0048
Shell side 2
Cross flow area
m
Mass velocity
kg/m .s
Linear velocity
m/s
Equivalent diameter
mm
2
Reynolds Prandtl Type of flow Nuselt number Stanton Number Heat transfer factor, jh Shell coeff, hs
2
W/m .K
0.0048
0.0048
0.0048
0.0048
6.917
12.796
18.675
24.900
30.780
0.00695
0.01285
0.01876
0.02501
0.03091
51.60
51.60
51.60
51.60
51.60
445.74
824.62
1203.50
1604.67
1983.55
5.44
5.44
5.44
5.44
5.44
laminar
laminar
laminar
laminar
laminar
5.29
8.66
11.72
14.75
17.48
0.00218
0.00193
0.00179
0.00169
0.00162
0.00679
0.00600
0.00557
0.00526
0.00504
63.15
103.30
139.78
175.96
208.47
Experiment 3.B: Co-Current Concentric Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density:
988.18
Heat capacity:
4175.00
Thermal cond:
0.6436
Viscosity:
kg/m
3
J/kg.K W/m.K
0.0005494
Pa.s
995.67
kg/m
Cold water Density: Heat capacity:
4183.00
Thermal cond:
0.6155
Viscosity:
0.0008007
3
J/kg.K W/m.K Pa.s
CALCULATIONS FOR CONCENTRIC HEAT EXCHANGER (Co-Current) Fixed Hot water flow rate at 10 LPM TEST 1
TEST 2
TEST 3
TEST 4
TEST 5
Hot fluid (Tube): Water Volumetric flowrate
L/min
Mass flow
kg/s
9.4
9.4
9.6
9.8
9.7
0.1548
0.1548
0.1581
0.1614
0.1598
Inlet temp
o
51.1
51.1
51.1
51.1
51.0
Outlet temp
o
C
49.7
49.7
49.7
49.7
49.6
Heat transfer rate
J/s
904.89
904.89
924.15
943.40
933.77
C
Cold fluid (Shell): Water Volumetric flowrate
L/min
Mass flow
kg/s
2.0
3.7
5.5
7.2
8.9
0.0332
0.0614
0.0913
0.1195
0.1477
Inlet temp
o
32.6
31.8
31.7
31.6
31.6
Outlet temp
o
C
35.7
33.9
33.0
32.7
32.5
Heat transfer rate
J/s
430.37
539.35
496.32
549.77
556.01
C
Temp difference Hot side inlet T, T1
o
51.1
51.1
51.1
51.1
51
Hot side outlet T, T2
o
49.7
49.7
49.7
49.7
49.6
Cold side inlet T, t1
o
32.6
31.8
31.7
31.6
31.6
Cold side outlet T, t2
o
35.7
33.9
33
32.7
32.5
T log mean, Tlm
o
C
16.15
17.49
18.02
18.22
18.23
Heat Loss
W
474.52
365.54
427.83
393.63
377.76
Efficiency
%
47.56
59.60
53.71
58.27
59.54
C C C C
Overall heat transfer coeff 2
Total exchange area
m
Overall heat transfer coeff
W/m .K
2
0.05
0.05
0.05
0.05
0.05
1068.26
986.05
977.71
986.84
976.53
Exchanger layout Tube
1
1
1
1
1
Shell
1
1
1
1
1
Length of tubes
m
Tube ID
mm
0.5
0.5
0.5
0.5
0.5
26.64
26.64
26.64
26.64
26.64
Tube OD
mm
33.4
33.4
33.4
33.4
33.4
Tube surface area
m
2
0.0525
0.0525
0.0525
0.0525
0.0525
Shell diameter
mm
85
85
85
85
85 5.57E-04
Tube side 2
Cross section area
m
5.57E-04
5.57E-04
5.57E-04
5.57E-04
Mass velocity
kg/m .s
277.75
277.75
283.66
289.57
286.61
Linear velocity
m/s
0.2811
0.2811
0.2871
0.2930
0.2900 13897.73
Reynolds
2
13467.90
13467.90
13754.45
14041.00
Prandtl
3.56
3.56
3.56
3.56
3.56
Nuselt number
70.36
70.36
71.55
72.74
72.15
Type of flow
turbulent
turbulent
turbulent
turbulent
turbulent
Stanton Number
1.47E-03
1.47E-03
1.46E-03
1.45E-03
1.46E-03
Heat transfer factor, jh Tube coeff, hi
2
W/m .K
3.43E-03
3.43E-03
3.42E-03
3.41E-03
3.41E-03
1699.75
1699.75
1728.63
1757.38
1743.02
4.80E-03
4.80E-03
4.80E-03
4.80E-03
4.80E-03
6.92
12.80
19.02
24.90
30.78
0.0069
0.0129
0.0191
0.0250
0.0309
Shell side 2
Cross flow area
m
Mass velocity
kg/m .s
Linear velocity
m/s
Equivalent diameter
mm
2
Reynolds Prandtl Type of flow Nuselt number Stanton Number Heat transfer factor, jh Shell coeff, hs
2
W/m .K
51.60
51.60
51.60
51.60
51.60
445.74
824.62
1225.79
1604.67
1983.55
5.44
5.44
5.44
5.44
5.44
laminar
laminar
laminar
laminar
laminar
5.29
8.66
11.89
14.75
17.48
2.18E-03
1.93E-03
1.78E-03
1.69E-03
1.62E-03
6.79E-03
6.00E-03
5.55E-03
5.26E-03
5.04E-03
63.15
103.30
141.85
175.96
208.47
Experiment 4.A: Counter-Current Plate Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density:
988.18
Heat capacity:
4175.00
Thermal cond:
0.6436
Viscosity:
kg/m
3
J/kg.K W/m.K
0.0005494
Pa.s
995.67
kg/m
Cold water Density: Heat capacity:
4183.00
Thermal cond:
0.6155
Viscosity:
0.0008007
3
J/kg.K W/m.K Pa.s
CALCULATIONS FOR COUNTER-CURRENT FLOW PLATE HEAT EXCHANGER Fixed Hot water flow rate at 7.5 LPM TEST 1
TEST 2
TEST 3
TEST 4
TEST 5
Hot fluid: Water Actual volume flow
L/min
Mass flow
kg/s
7.18
7.18
7.18
7.18
7.18
0.11825
0.11825
0.11825
0.11825
0.11825
Inlet temp (calibrated temp)
o
50.5
50.5
50.5
50.5
50.5
Outlet temp (calibrated temp)
o
C
45.9
43.5
41.6
40.4
39.7
Heat transfer rate
J/s
2298.2
3487.2
4379.0
4973.5
5320.3
C
Cold fluid: Water Actual volume flow
L/min
Mass flow
kg/s
2.10
3.74
5.48
7.39
8.82
0.03485
0.06206
0.09094
0.12263
0.14636
Inlet temp (calibrated temp)
o
32.9
32.5
32.5
32.5
32.5
Outlet temp (calibrated temp)
o
C
48.2
45.9
43.8
42.0
41.1
Heat transfer rate
J/s
2235.6
3458.0
4261.5
4867.7
5254.1
C
Temp difference Hot side inlet T, T1
o
50.52
50.52
50.52
50.52
50.52
Hot side outlet T, T2
o
45.86
43.45
41.65
40.44
39.74
Cold side inlet T, t1
o
32.85
32.55
32.55
32.55
32.55
Cold side outlet T, t2
o
48.19
45.87
43.75
42.04
41.13
T log mean, Tlm
o
C
6.21
7.34
7.87
8.18
8.24
W
62.6
29.3
117.5
105.9
66.3
%
97.3
99.2
97.3
97.9
98.8
0.092
0.092
0.092
0.092
0.092
4024.32
5167.48
6046.14
6607.78
7019.42
1.29
1.29
1.29
1.29
1.29
6
6
6
6
6
Heat loss Efficiency
C C C C
Overall heat transfer coeff Total plate area Overall heat transfer coeff
2
m
2
W/m .K
Exchanger layout Plate channel
mm
No of plates Plate width
mm
71
71
71
71
71
Plate Length
mm
308
308
308
308
308
Plate area
m
2
Cross sectional area
m
2
0.018
0.018
0.018
0.018
0.018
0.00009
0.00009
0.00009
0.00009
0.00009
Plate film coefficient (hot) 2
Total cross section
m
2.75E-04
2.75E-04
2.75E-04
2.75E-04
2.75E-04
Equivalent diameter, de
m
2.58E-03
2.58E-03
2.58E-03
2.58E-03
2.58E-03
Mass velocity
kg/m .s
430.37
430.37
430.37
430.37
430.37
Linear velocity
m/s
0.4355
0.4355
0.4355
0.4355
0.4355
2021.02
2021.02
2021.02
2021.02
2021.02
3.56
3.56
3.56
3.56
3.56
Reynolds Prandtl
2
Hot film coeff
2
W/m .K
15183.17
15183.17
15183.17
15183.17
15183.17
Plate film coefficient (cold) 2
Total cross section
m
2.75E-04
2.75E-04
2.75E-04
2.75E-04
2.75E-04
Equivalent diameter, de
m
2.58E-03
2.58E-03
2.58E-03
2.58E-03
2.58E-03
Mass velocity
kg/m .s
126.8277
225.8741
330.9599
446.3128
532.6764
Linear velocity, Gp
m/s
0.1274
0.2269
0.3324
0.4483
0.5350
408.66
727.81
1066.41
1438.10
1716.38
2
Reynolds Prandtl Cold film coeff
2
W/m .K
5.44
5.44
5.44
5.44
5.44
6084.99
8854.91
11350.76
13785.94
15465.79
Experiment 4.B: Co-Current Plate Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density:
988.18
Heat capacity:
4175.00
Thermal cond:
0.6436
Viscosity:
kg/m
3
J/kg.K W/m.K
0.0005494
Pa.s
995.67
kg/m
Cold water Density: Heat capacity:
4183.00
Thermal cond:
0.6155
Viscosity:
0.0008007
3
J/kg.K W/m.K Pa.s
CALCULATIONS FOR CO-CURRENT FLOW PLATE HEAT EXCHANGER Fixed Hot water flow rate at 7.5 LPM TEST 1
TEST 2
TEST 3
TEST 4
TEST 5
Hot fluid: Water Actual volume flow
L/min
6.66
6.66
6.66
6.66
6.66
Mass flow
kg/s
0.11
0.11
0.11
0.11
0.11
Inlet temp (calibrated temp)
o
50.5
50.5
50.5
50.5
50.5
Outlet temp (calibrated temp)
o
C
46.6
44.7
42.8
41.9
41.4
Heat transfer rate
J/s
1792.86
2683.23
3510.42
3924.01
4153.79
C
Cold fluid: Water Actual volume flow
L/min
2.07
3.68
5.74
7.50
8.88
Mass flow
kg/s
0.03
0.06
0.10
0.12
0.15
Inlet temp (calibrated temp)
o
33.7
33.4
33.1
32.9
32.9
Outlet temp (calibrated temp)
o
C
46.0
43.8
41.4
40.3
39.5
Heat transfer rate
J/s
1764.58
2673.72
3327.30
3875.40
4091.55
C
Temp difference Hot side inlet T, T1
o
50.52
50.52
50.52
50.52
50.52
Hot side outlet T, T2
o
46.60
44.66
42.85
41.95
41.44
Cold side inlet T, t1
o
33.67
33.37
33.07
32.86
32.86
Cold side outlet T, t2
o
45.95
43.83
41.42
40.31
39.50
T log mean, Tlm
o
Heat loss Efficiency
C C C C C
4.97
5.37
6.41
6.74
7.12
W
28.28
9.51
183.12
48.62
62.24
%
98.42
99.65
94.78
98.76
98.50
0.092
0.092
0.092
0.092
0.092
3918.48
5429.50
5954.82
6331.88
6342.69
1.29
1.29
1.29
1.29
1.29
6
6
6
6
6
Overall heat transfer coeff Total plate area Overall heat transfer coeff
2
m
2
W/m .K
Exchanger layout Plate channel
mm
No of plates Plate width
mm
71
71
71
71
71
Plate Length
mm
308
308
308
308
308
Plate area
m
2
Cross sectional area
m
2
0.018
0.018
0.018
0.018
0.018
0.00009
0.00009
0.00009
0.00009
0.00009
Plate film coefficient (hot) 2
Total cross section
m
2.75E-04
2.75E-04
2.75E-04
2.75E-04
2.75E-04
Equivalent diameter, de
m
2.58E-03
2.58E-03
2.58E-03
2.58E-03
2.58E-03
Mass velocity
kg/m .s
399.20
399.20
399.20
399.20
399.20
Linear velocity
m/s
0.40
0.40
0.40
0.40
0.40
1874.65
1874.65
1874.65
1874.65
1874.65
3.56
3.56
3.56
3.56
3.56
Reynolds Prandtl
2
Hot film coeff
2
W/m .K
14459.05
14459.05
14459.05
14459.05
14459.05
Plate film coefficient (cold) 2
Total cross section
m
2.75E-04
2.75E-04
2.75E-04
2.75E-04
2.75E-04
Equivalent diameter, de
m
2.58E-03
2.58E-03
2.58E-03
2.58E-03
2.58E-03
Mass velocity
kg/m .s
125.02
222.25
346.66
452.96
536.30
Linear velocity, Gp
m/s
0.13
0.22
0.35
0.45
0.54
402.82
716.13
1117.01
1459.51
1728.06
2
Reynolds Prandtl Cold film coeff
2
W/m .K
5.44
5.44
5.44
5.44
5.44
6028.35
8762.31
11697.97
13918.98
15534.10
APPENDIX E SAMPLE CALCULATIONS
Sample Calculation for Shell and Tube Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density: Heat capacity: Thermal cond: Viscosity: Cold water Density: Heat capacity: Thermal cond: Viscosity:
988.18 4175.00 0.6436 0.0005494
kg/m3 J/kg.K W/m.K Pa.s
995.67 4183.00 0.6155 0.0008007
kg/m3 J/kg.K W/m.K Pa.s
Cold Water Flowrate = 2.0 LPM COUNTER-CURRENT FLOW (Hot water inlet at 50'C) Hot fluid (Tube-side): Water Volume flow Inlet temp Outlet temp Cold fluid(Shell-Side): Water Volume flow Inlet temp Outlet temp
L/min oC oC
10.0 50.8 48.6
L/min oC oC
2.0 31.2 40.7
SHELL AND TUBE HEAT EXCHANGER LAYOUT Tube Shell
1 1
Length of tubes Tube ID Tube OD Tube pitch
m mm mm mm
0.5 7.75 9.53 18
Tube surface area Number of tubes Shell diameter Baffle length Baffle Cut
m2
0.015 10 85 50 20
mm mm %
1. Calculation of Heat transfer and heat Lost: The Heat Transfer rate of both hot and cold water are both calculated using the heat balance equation. Heat Transfer Rate for Hot Water, Q hot (W) m h C p T
L 1 m3 1 min kg J 988 .18 3 4175 (50 .8 48 .6 ) C min 1000 L 60 s kg .C m 1512 .74W
10 . 0
Heat Transfer Rete for Cold Water, Qcold (W) mc C p T 1 m 3 1 min L kg J 995.67 3 4183 (40.7 31.2)C min 1000 L 60s kg.C m 1318.88W 2.0
Heat Lost Rate Qhot Qcold
1512.74 1318.88 193.86 W
Efficiency Qcold / Qhot 100%
1318.88 100% 87.18 % 1512.74
2. Calculation of Log Mean Temperature Difference: Tlm Th, in Tc, out Th, out Tc, in / lnTh, in Tc, out / Th, out Tc, in
(50.8 40.7) (48.6 31.2) 13.42 C 50.8 40.7 ln 48.6 31.2
3. Calculation of the tube and shell heat transfer coefficients by Kern’s method: For 1-shell pass; 1-tube pass, Tm = Tlm
Heat transfer coefficient at Tube side: Cross Flow Area, A
2
=
πdi 4
=
3.142 0.00775 2 4
= 0.0000472 m2 Total cross Flow Area, At = 0.0000472 x number of tubes = 0.0000472 x 10 = 0.000472 m2
Mass velocity, Gt
=
mt At
=
0.1647 0.000472
= 349.13 kg/m2.s
Linear Velocity, ut
=
Gt ρ
=
349.13 988.18
= 0.3533 m/s
Renolds No, Re
= =
G t de
349.13 7.75 1 0.0005494 1000
= 4924.8 (Turbulent Flow)
Prandtl No, Pr
= =
Cp k 0.0005494 4175 0.6436
= 3.56 Tube side heat transfer factor, jh = 0.0039 (From Fig. C.2, Appendix C)
Tube Side Coefficient, hi
j h Re Pr 0.33 k di
= =
0.0039 4924.98 3.56 0.33 0.6436 0.00775
= 2426.16 Wm-2K Heat transfer coefficient at shell side:
Cross Flow Area, As = [(Tube pitch-Tube OD) x (Shell Diameter) x (Baffle distance)]/Tube pitch = 0.002 m2
Mass velocity, Gs
=
Ws As
=
0.0332 0.002
= 16.60 kg/m2.s
Linear Velocity, us = =
Gs ρ 16.60 995.67
= 0.0167m/s
Equivalent Diameter, de = =
1.1 2 2 p t 0.917d o do
1.1 18 2 0.917(9.53) 2 9.53
= 27.78 mm
Reynolds Number, Re = =
G s de
16.60 27.78 1 0.0008007 1000
= 575.88 (Laminar Flow)
Prandtl No, Pr
=
=
Cp k 0.0008007 4183.00 0.6155
= 5.44 Shell side heat transfer factor, jh = 0.023 (From Fig. C.4, Appendix C)
Shell Side Coefficient, hi
=
jh Re Pr 0.33 k de
=
0.023 605.16 5.44 0.33 0.6155 0.02053
= 513.18 W/m2.K Overall heat transfer coefficient:
Total exchange area, A = Number of tube x = 10 x
x Tube OD x Length of Tubes
x (9.53/1000) x 0.5
= 0.15 m2 Overall heat transfer coefficient, U
=
Q hot A Tlm
= 752.97 W/m2.K
4. Calculation of Pressure Drop across Tube and Shell
Pt N p
u t2 2
8 j
f
( L / d i ) w
m
2.5
988.18 0.3533 2 8 0.0058 (0.5 / 0.00775) 2.5 2 = 338.8 Pa
=
Ps 8 j f (D s / d e )(L / l B )
u s2
w 0.14
2 2 0.085 0.5 (995.67)(0.0167) 1.00.14 Ps (8)(0.098) 2 0.02778 0.05 3.3 Pa
The pressure drop measured experimentally is the combination of pressure drop across the heat exchanger construction and fittings. Therefore, the measured pressure drops will be much greater than the actual pressure drops across the heat exchanger. 5. Temperature Profile for counter-current Shell and Tube Heat Exchanger
6. Heat transfer Coefficient Study
Sample Calculation for Spiral Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density: Heat capacity: Thermal cond: Viscosity: Cold water Density: Heat capacity: Thermal cond: Viscosity:
988.18 4175.00 0.6436 0.0005494
kg/m3 J/kg.K W/m.K Pa.s
995.67 4183.00 0.6155 0.0008007
kg/m3 J/kg.K W/m.K Pa.s
Cold Water Flowrate = 2.0 LPM COUNTER-CURRENT FLOW (Hot water inlet at 50'C) Hot fluid (Tube-side): Water
Volume flow Inlet temp Outlet temp Cold fluid(Shell-Side): Water Volume flow Inlet temp Outlet temp
L/min oC oC
4.90 51.0 47.9
L/min oC oC
2.10 31.1 37.6
SPIRAL HEAT EXCHANGER LAYOUT Coil Shell
1 1
Length of tubes
m
5
Tube ID Tube OD Coil surface area
mm mm m2
7.05 9.53 0.15
Shell diameter
mm
85
Coil ID Coil OD
mm mm
34 44
1. Calculation of Heat transfer and heat Lost:
The Heat Transfer rate of both hot and cold water are both calculated using the heat balance equation. Heat Transfer Rate for Hot Water, Q hot (W) m h C p T
L kg 1 m3 1 min 988 .18 3 min 1000 L 60 s m J 4175 ( 51 . 0 47 .9 ) C kg .C 1044 .48 W 4 .90
Heat Transfer Rete for Cold Water, Qcold (W) mc C p T 1 m 3 1 min L kg 995.67 3 min 1000 L 60s m J 4183 (37.6 31.1)C kg.C 947.51 W
2.1
Heat Lost Rate Qhot Qcold
1044.48 947.51 96.97 W
Efficiency Qcold / Qhot 100%
947.51 100% 90.72 % 1044.48
2. Calculation of Log Mean Temperature Difference: Tlm Th, in Tc, out Th, out Tc, in / lnTh, in Tc, out / Th, out Tc, in (51.0 37.6) (47.9 31.1) 15.04 C 51.0 37.6 ln 47.9 31.1
3. Calculation of the tube and shell heat transfer coefficients by Kern’s method:
Assuming, Tm = Tlm
Heat transfer coefficient at Tube side:
Cross Flow Area, At
2
=
πdi 4
=
3.142 0.00705 2 4
= 0.000039 m2
mt At
=
Mass velocity, Gt
=
0.0807 0.000039
= 2067.34 kg/m2.s
Linear Velocity, ut
=
Gt ρ
=
2067.34 988.18
= 2.09 m/s
Renolds No, Re
= =
G t de
2067.34 7.05 1 0.0005494 1000
= 26528.53 (Turbulent Flow)
Prandtl No, Pr
= =
Cp k 0.0005494 4175 0.6436
= 3.56
0.023 Re 0.8 Pr 0.33 k = de
Tube Side Coefficient, hi
=
0.023 26528.530.8 3.56 0.33 0.6436 0.00705
= 11047.45Wm-2K Heat transfer coefficient at shell side:
Cross Flow Area, As = =
D 4
4
2
2
D 2 D1
3
0.085
2
2
0.044 2 0.033 2
= 0.00506 m2
Mass velocity, Gs
=
Ws As
=
0.0332 0.00506
= 6.88kg/m2.s
Linear Velocity, us = =
Gs ρ 6.88 995.67
= 0.00691m/s
d Equivalent Diameter, de =
2
2
d 2 d1 d1 d 2 d 3 3
85 =
2
44 2 34 2 85 44 34 2
= 39.54 mm
Reynolds Number, Re = =
G s de
6.88 39.54 1 0.0008007 1000
= 339.97 (Laminar Flow)
Prandtl Number, Pr
= =
Cp k 0.0008007 4183.00 0.6155
= 5.44 Nuselt Number, Nu
= 0.023 Re 0.8 Pr 0.33 = 0.023 339.97 0.8 5.44 0.33 = 4.26
Stanton Number, St
= =
Nu Re Pr
4.27 339.97 5.44
= 0.00230 Heat transfer factor, jh = St Pr 0.67 = 0.00230 5.44 0.67 = 0.00717
Shell Side Coefficient, hs
=
jh Re Pr 0.33 k de
=
0.00717 339.97 5.44 0.33 0.6155 0.03954
= 66.35W/m2.K
Overall heat transfer coefficient:
Total exchange area, A =
x (0.00953/1000) x 5.0
= 0.15 m2 Overall heat transfer coefficient, U
=
Q hot A Tlm
= 420.96 W/m2.K 4. Temperature Profile for counter-current Spiral Heat Exchanger
5. Heat transfer Coefficient Study
Sample Calculation for Concentric Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density: Heat capacity: Thermal cond: Viscosity: Cold water Density: Heat capacity: Thermal cond: Viscosity:
988.18 4175.00 0.6436 0.0005494
kg/m3 J/kg.K W/m.K Pa.s
995.67 4183.00 0.6155 0.0008007
kg/m3 J/kg.K W/m.K Pa.s
Cold Water Flowrate = 2.0 LPM COUNTER-CURRENT FLOW (Hot water inlet at 50'C) Hot fluid (Tube-side): Water
Volume flow Inlet temp Outlet temp Cold fluid(Shell-Side): Water Volume flow Inlet temp Outlet temp
L/min oC oC
9.70 51.1 50.0
L/min oC oC
2.0 32.7 35.3
SHELL AND TUBE HEAT EXCHANGER LAYOUT Tube 1 Shell 1
Length of tubes
m
0.5
Tube ID Tube OD Tube surface area
mm mm m2
26.64 33.4 0.0525
Shell diameter
mm
85
1. Calculation of Heat transfer and heat Lost:
The Heat Transfer rate of both hot and cold water are both calculated using the heat balance equation. Heat Transfer Rate for Hot Water, Q hot (W) m h C p T
1 m3 1 min L kg 988 .18 3 min 1000 L 60 s m J 4175 ( 51 . 1 50 .0 )C kg . C 733 .68W
9 .70
Heat Transfer Rete for Cold Water, Qcold (W) mc C p T 1 m 3 1 min L kg 995.67 3 min 1000 L 60s m J 4183 (35.3 32.7)C kg.C 360.96 W
2.0
Heat Lost Rate Qhot Qcold
733.68 360.96 372.72 W
Efficiency Qcold / Qhot 100%
360.96 100% 49.20 % 733.68
2. Calculation of Log Mean Temperature Difference: Tlm Th, in Tc, out Th, out Tc, in / lnTh, in Tc, out / Th, out Tc, in (51.1 35.3) (50.0 32.7) 16.54 C 51.1 35.3 ln 50.0 32.7
3. Calculation of the tube and shell heat transfer coefficients by Kern’s method:
Assuming, Tm = Tlm
Heat transfer coefficient at Tube side:
Cross Flow Area, At
2
=
πdi 4
=
3.142 0.02664 2 4
= 0.000557 m2
mt At
=
Mass velocity, Gt
=
0.1597 0.000557
= 286.61 kg/m2.s
Linear Velocity, ut
=
Gt ρ
=
286.61 988.18
= 0.29004 m/s
Renolds Number, Re
= =
G t de
286.61 26.64 1 0.0005494 1000
= 13897.73 (Turbulent Flow)
Prandtl No, Pr
= =
Cp k 0.0005494 4175 0.6436
= 3.56
= 0.023 Re 0.8 Pr 0.33
Nuselt Number, Nu
= 0.023 13897.730.8 3.56 0.33 = 72.15
Stanton Number, St
=
Nu Re Pr
=
72.15 13897.73 3.56
= 0.00146 Heat transfer factor, jh = St Pr 0.67 = 0.00146 3.56 0.67 = 0.00341 0.023 Re 0.8 Pr 0.33 k = di
Tube Side Coefficient, hi
=
0.023 13897.730.8 3.56 0.33 0.6436 0.02664
= 1743.02 Wm-2K Heat transfer coefficient at shell side:
Cross Flow Area, As =
D 4
2 s
do
2
= 0.0048 m2
Mass velocity, Gs
=
Ws As
=
0.0332 0.0048
= 6.917 kg/m2.s
Linear Velocity, us =
Gs ρ
=
6.917 995.67
= 0.00695 m/s Equivalent Diameter, de = d 2 d1 = 85.0 33.4 = 51.6 mm
Reynolds Number, Re = =
G s de
6.917 51.6 1 0.0008007 1000
= 445.74 (Laminar Flow)
Prandtl No, Pr
= =
Cp k 0.0008007 4183.00 0.6155
= 5.44 Nuselt Number, Nu
= 0.023 Re 0.8 Pr 0.33 = 0.023 445.74 0.8 5.44 0.33 = 5.29
Stanton Number, St
=
Nu Re Pr
=
5.29 445.74 5.44
= 0.00218 Heat transfer factor, jh = St Pr 0.67 = 0.00218 5.44 0.67 = 0.00679 Shell Side Coefficient, hs
=
jh Re Pr 0.33 k de
0.00679 445.74 5.29 0.33 0.6155 = 0.0516 = 63.15 W/m2.K Overall heat transfer coefficient:
Total exchange area, A =
x Tube OD x Length of Tubes
=
x (26.64/1000) x 0.5
= 0.05 m2 Overall heat transfer coefficient, U
=
Q hot A Tlm
= 845.55 W/m2.K
4. Temperature Profile for counter-current Shell and Tube Heat Exchanger
5. Heat transfer Coefficient Study
Sample Calculation for Plate Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density: Heat capacity: Thermal cond: Viscosity: Cold water Density: Heat capacity: Thermal cond: Viscosity:
988.18 4175.00 0.6436 0.0005494
kg/m3 J/kg.K W/m.K Pa.s
995.67 4183.00 0.6155 0.0008007
kg/m3 J/kg.K W/m.K Pa.s
Cold Water Flowrate = 2.0 LPM COUNTER-CURRENT FLOW (Hot water inlet at 50'C) Hot fluid (Tube-side): Water Volume flow Inlet temp Outlet temp Cold fluid(Shell-Side): Water Volume flow Inlet temp Outlet temp
L/min oC oC
7.18 50.5 45.9
L/min oC oC
2.10 32.9 48.2
PLATE HEAT EXCHANGER LAYOUT
Total cross section area Plate width
m2 mm
0.000275 71
Plate length Plate channel No. of plate
mm mm
308 1.29 6
1. Calculation of Heat Lost and Efficiency:
The heat transfer rate of both hot and cold water is both calculated using the heat balance equation. heat trans fer rate for Hot Water, Q hot (W) m h C p T
7 .18 m 3 1 min kg 988 . 18 3 1000 min 60 s m J 4175 ( 50 . 5 45 .9 )C kg .C 2298 .2 W
Heat transfer rate for Cold Water, Qcold (W) mc C p T kg 2.10 m 3 1 min 995.67 3 1000 min 60s m J 4183 (48.2 32.9)C kg.C 2235.6 W
Power Lost = Qhot Qcold
2298.2 2235.6 62.6 W
Efficiency Qhot / Qcold 100%
2235.6 100% 97.3 % 2298.2
2. Calculation of Log Mean Temperature Difference:
Tlm Th, in Tc, out Th, out Tc, in / lnTh, in Tc, out / Th, out Tc, in
(50.5 48.2) (45.9 32.9) 6.21 C 50 . 5 48 . 2 ln 45.9 32.9
3. Calculation of the hot and cold plate heat transfer coefficients: Heat Transfer Coefficient at Hot Plate
Mass Velocity
=
Mass Flow Rate Total Cross Section Area
=
0.11825kg/s 0.000275 m 2
= 430.37 kg/m2.s
Linear Velocity
=
Mass Velocity Density
430.37kg/m 2 s = 988.18 kg/ m 3 = 0.4355 m/s Equivalent Diameter, de
= 2 depth = 2 x 0.00129 = 0.00258 m
Reynolds No
=
Mass Velocity de viscocity
=
430.37kg/m 2 s 0.00258m 0.0005494 Pa.s
= 2021.02
Prandtl No
=
Heat Capacity Viscocity ThermalConductivity
=
4175.00 J/kg.C 0.0005494 Pa.s 0.6436 W/m.s
= 3.56 Plate Film Coefficient at Hot Side, hpH
0.26 Re 0.65 Pr 0.4 k = de =
0.26 2021.02 0.65 x 3.56 0.4 0.6436 0.00258
= 15183.17 W/m2.K Heat Transfer Coefficient at Cold Plate
=
Mass Flow Rate Total Cross Section Area
=
0.03485 kg/s 0.000275 m 2
Mass Velocity
= 126.8277 kg/m2.s
Linear Velocity
=
Mass Velocity Density =
126.8277 kg/m 2 s 995.67 kg/ m 3
= 0.1274 m/s
Reynolds No
=
Mass Velocity de viscocity
=
126.8277 kg/m 2 s 0.00258 m 0.00080071Pa.s
= 408.66
Prandtl No
=
Heat Capacity Viscocity ThermalConductivity
=
4183.00 J/kg.C 0.0008007 Pa.s 0.6155 W/m.s
= 5.44 Plate Film Coefficient at Cold Side, hpC
0.26 Re 0.65 Pr 0.4 k = de =
0.26 408.66 0.65 5.44 0.4 0.6155 0.00258
= 6084.99W/m2.K
4. Temperature profile for counter-current Plate Heat Exchanger
5. Heat transfer Coefficient Study
APPENDIX F TEMPERATURE SENSOR CALIBRATION
Temperature Sensor Calibration Table Actual Temperature 30 35 40 45 50 55 60 65 70 75 80 85 90 slope correcting factor for the calibrated sensor temperature
T1 30.0 35.0 40.0 44.8 49.6 54.5 59.7 64.0 69.6 74.5 79.6 84.2 88.8 0.9920 1.0081
Sensor Temperature T2 T3 T4 29.7 30.0 29.2 34.8 35.0 34.0 39.7 40.0 39.7 44.6 45.0 44.6 49.5 49.7 49.4 54.4 54.8 54.5 59.6 60.0 59.5 64.4 64.8 64.4 69.5 69.8 69.4 74.4 74.8 74.4 79.4 79.8 79.2 84.4 84.6 84.2 89.5 89.3 89.0 0.9924 0.9965 0.9898 1.0077
1.0035
1.0103
Note: The temperature recorded from the indicator need to multiply the correcting factor to get the accurate temperature reading.
