HE158C EXPERIMENTAL MANUAL.pdf

EXPERIMENTAL MANUAL

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: 603-80755784E-MAIL: [email protected]

WEBSITE: www.solution.com.my

236-0510-HE

HEAT EXCHANGERTRAINING

APPARATUS

HEAT EXCHANGERTRAINING

APPARATUS

SOLTEQ® EQUIPMENT FOR ENGINEERING EDUCATION

Table of Contents

Page

List of Figures ....................................................................................................................................... i

List of Tables ....................................................................................................................................... ii

1.0 INTRODUCTION ........................................................................................................................... 1

2.0 GENERAL DESCRIPTION

2.1 Description and Assembly .................................................................................................. 2

2.2 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 Spiral Heat Exchanger ...................................................................................................... 17

4.3 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 Experiment 2.B: Co-Current Spiral Heat Exchanger ........................................................ 27

6.5 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

i

List of Figures Page Figure 1 Schematic Diagram for Heat Exchanger Training Apparatus 4

(Model: HE 158 C)

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

ii

List of Tables Page Table 1 Valves Arrangement for Flow Selection 5 Table 2 Valves Arrangement for Heat Exchanger Selection 5

SOLTEQ® HEAT EXCHANGER TRAINING APPARATUS (Model: HE 158C) _______________________________

1

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


2

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) : 9.53 mm Tube I.D. (di) : 7.75 mm Tube Length (L) : 500 mm Tube Count (Nt) : 10 (single pass) Tube Pitch (pt) : 18 mm Tube arrangement : Triangle Shell O.D. : 100 mm Shell I.D. (Ds) : 85 mm Baffle Count : 8 Baffle Cut (Bc) : 20 % Baffle Distance (lB) : 50 mm Material of Construction : 316L Stainless Steel/Borosilicate Glass

b) Spiral Heat Exchanger Coil Tubing O.D. : 9.53 mm Coil Tubing I.D. : 7.05 mm Coil Length (L) : 5.00 m Shell O.D. : 100 mm Coil I.D. : 34 mm Coil O.D. : 44 mm Shell I.D. (Ds) : 85 mm Material of Construction : 316L Stainless Steel/Borosilicate

c) Concentric (Double Pipe) Heat Exchanger Tube O.D. (do) : 33.40 mm Tube I.D. (di) : 26.64 mm 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 : 0.50 m2 Plate Material : 316L stainless steel/copper brazed

No.of plates : 4 Plate length : 309.88 mm Plate channel : 43.18 mm Plate width : 124.46 mm


3

e) Cold Water Circuit Tank : 50 liter Material : Stainless Steel Circulation Pump : Centrifugal type Operating Flow rate : 10 LPM (dry-run protected by level switch)

f) Hot Water Circuit

Tank : 50 liter Material : Stainless Steel Circulation Pump : Centrifugal type Operating Flow rate : 20 LPM (dry-run protected by level switch) Heating System : 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


4

Figure 1: Schematic Diagram for Heat Exchanger Training Apparatus (Model: HE 158 C)


5

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 OPEN CLOSE LEAVE ALONE Co-Current

V1, V12, V16, V17, V28

V15, V18, V27, V29, V30

V2, V3, V4 - V11, V13, V14, V19 - V26

Counter-Current

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 CLOSE Shell & Tube Heat Exchanger V4, V5, V19, V20 V6 - V11, V21 - V26

Spiral Heat Exchanger

V6, V7, V21, V22 V4, V5, V8 - V11, V19, V20, V23 - V26

Concentric Heat Exchanger

V8, V9, V23, V24 V4 - V7, V10, V11, V19 - V22, V25, V26

Plate Heat Exchanger V10, V11, 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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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 : max. 70 ºC 2.4 Overall Dimensions

Height : 1.60 m Width : 2.00 m Depth : 0.60 m

2.5 General Requirements

Electrical : 415VAC/50Hz (3 phase) @ 50Amps Cooling water : Laboratory tap water, 20 LPM @ 2 m head Drainage point


7

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.


8

4.0 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.

T1, ms

T2

T2

t2ΔT2

T1

Heat Transfered

Flu

id T

emp

.

t1t2t1, mt

ΔT1

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.


9

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 (2) where, mt = mass flowrate of cold fluid in the tube (kgs-1) ms = mass flowrate of hot fluid in the shell (kgs-1) Cpt = specific heat of cold fluid in the tube (kJkg-1°C-1) Cps = specific heat of hot fluid in the shell (kJkg-1°C-1) t1, t2 = temperature of cold fluid entering/leaving the tube (°C) T1, T2 = temperature of hot fluid entering/leaving the shell (°C) q = 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 = outside area of the tube (m2) Ai = inside area of the tube (m2) Tm = mean temperature difference (°C) Uo = overall heat transfer coefficient based on the outside area of the tube (kWm-2°C-1) Ui = overall heat transfer coefficient based on the inside area of the tube (kWm-2°C-1) The coefficients Uo and Ui are given by:

ii

o

idi

o

w

ioo

odoo hdd

hdd

kddd

hhU

2)ln(111

(4)

and,

oo

i

odo

i

w

ioi

idii hdd

hdd

k

ddd

hhU

2

)ln(111 (5)


10

where, ho = outside fluid film coefficient (kWm-2°C-1) hi = inside fluid film coefficient (kWm-2°C-1) hod = outside dirt coefficient (fouling factor) (kWm-2°C-1) hid = inside dirt coefficient (kWm-2°C-1) kw = thermal conductivity of the tube wall material (kWm-1°C-1) do = tube outside diameter (m) di = 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,

2

1

21

ln TT

TTTlm (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:

)()(

12

21

ttTT

R

and, )()(

11

12

tTtt

S

(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: 14.033.08.0 )/(PrRe wfCNu (9) where, Re = Reynolds Number = fetfetf dGdu //

Nu = Nusselt Number = fei kdh /

Pr = Prandtl Number = ffp kC /

de = equivalent (or hydraulic) diameter (m) = 4 x (cross-sectional area of flow) / wetted perimeter = di for tubes


11

Gt = mass velocity, mass flow per unit area (kg/ s.m2) µf = fluid viscosity of bulk fluid temperature (Nsm-2) µw = fluid viscosity at the wall (Nsm-2) ρf = fluid density (kgm-3) ut = fluid velocity in tube (ms-1) Cp = fluid specific heat, heat capacity (J/kg°C) C = 0.023 for non-viscous liquids = 0.027 for viscous liquids fk = Fluid thermal conductivity (W/m°C) For laminar flow (Re < 2000), the following correlation is used:

14.033.033.0 )/(Pr).(Re86.1 wfe LdNu (10) where, L = the tube length (m) Tube-side Pressure Drop, Pt The tube-side pressure drop is given by:

2

5.2)/(82tfm

wifpt

udLjNP

(11)

where, Pt = tube-side pressure drop (N/m2) Np = number of tube-side passes

jf = tube dimensionless friction factor (Figure C.3 in Appendix C)

L = length of one tube, (m) ut = tube-side velocity (m/s) m = 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:

tBsots plDdpA /)( (12) where, do = tube outside diameter (m) pt = tube pitch (m) Ds = shell inside diameter (m) lB = distance between baffle (m)


12

Then, the shell-side mass velocity, Gs and linear velocity, us are calculated as follows:: Gs = W s /A s (13)

us = G s /ρ f (14) where, W s = Fluid flowrate on the shell-side (kg/s) ρ f = shell-side fluid density (kg/m3) The shell equivalent diameter, de is given by:

22

22

785.027.1

)4/(4

oto

o

ote

dpd

ddp

d

(15)

(For square pitch arrangement)

22

2

917.010.1

2/

4/21

87.02

4

oto

o

ott

e

dpd

d

dpp

d

(16)

(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:

14.033.0PrRe/ wfhfes jkdhNu (18)


13

Shell-side Pressure Drop, Ps (Kern’s Method) The shell-side pressure drop is given by:

14.02

2)/)(/(8 wf

sBesfs

ulLdDjP

(19)

where, ΔPs = shell pressure drop (N/m2) jf = shell dimensionless friction factor from Figure C.5 lB = distance between baffle (m) us = shell-side velocity (m/s) Shell-side Heat-transfer Coefficient, hs (Bell’s Method) The shell-side heat transfer coefficient is given by:

Lbwnocs FFFFhh (20)

where, hoc = heat transfer coefficient calculated for cross-flow over an ideal tube bank, no leakage or by-passing, Fn = correction factor to allow for the effect of the number of vertical tube rows, Fw = window effect correction factor, Fb = by-pass stream correction factor, FL = leakage correction factor. The ideal cross-flow heat transfer coefficient hoc is given by,

14.033.0 )(PrRe wfhf

ooc jk

dh (21)

where, Re = 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, hj 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, 18.0)( cn NF

where cN = numbers of rows crossed in series from end to end of the

shell.


14

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,

2/ for /21exp 31cvscvs

s

bb NNNN

A

AF

(22)

where, = 1.5 for laminar flow, Re < 100, = 1.35 for transitional and turbulent flow Re > 100 Ab = clearance area between the bundle and the shell As = maximum area for cross-flow

Ns = number of sealing strips encountered by the by-pass stream in the cross-flow zone Ncv = the number of constrictions, tube rows, encountered in the cross-flow section.

If there is no sealing strips used, Fb is obtained from Figure C.9. The leakage correction factor FL is,

LsbtbLL AAAF /21 (23)

where L = a factor obtained from Figure C.10. Atb = tube-to-baffle clearance area, per baffle, Asb = shell-to-baffle clearance area, per baffle, AL = 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. Lbic FFPP (24)

where, Pi = pressure drop calculated for an equivalent ideal tube bank,

= 14.02

28

ws

cvf

uNj

(25)

Ncv = number of tube rows crossed (in the cross-flow region),


15

us = shell-side velocity, based on the clearance area As at the bundle equator,

jf = friction factor from Figure C.11 for Re calculated with us bF = by-pass correction factor,

LF = leakage correction factor. Calculate bF 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

bF from Figure C.12.

Calculate LF from Equation 22 taking L from Figure C.13. The window-zone pressure drop is,

2)6.02( 2zwvLw uNFP (26)

where, uz = geometric mean velocity, = swuu

uw = velocity in the window zone = ws AW ,

Ws = shell-side fluid mass flow (kg/s), Nwv = number of restrictions for cross-flow in window zone, approximately equal to the number of tube rows.

The end-zone pressure drop is,

bcvcvwvie FNNNPP (27)

Thus, the total shell-side pressure drop is the sum of pressure drops over all the zones in series from inlet to outlet:

wbcbe

bbs

PNPNP

NNP

)1(2=

zones) (window + zones) (crossflow)1( + zones) 2(end

(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 = baffle cut height = Bc x Ds, where Bc is the baffle cut as a fraction,

Hb = height from the baffle chord to the top of the tube bundle,


16

Bb = “bundle cut” = Hb / Db, b = angle subtended by the baffle chord (rads), Db = bundle diameter Subsequently,

)5.0(2/ csbb BDDH (30)

tbbcv pHDN /)2( (31)

tbwv pHN / (32)

where tp = 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:

atw RNN (33)

where aR 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)

)4()4( 22owsaw dNDRA (36)

where Ra is obtained from Figure C.15 for the appropriate baffle cut, Bc.

)()2( wtottb NNdcA (37)

where ct is the diametrical tube-to-baffle clearance, typically 0.8mm.

)2()2( bsssb DcA (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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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.

de = perimeterwetted

areationalcross sec4 (40)

= 123

21

22

234

4

ddd

ddd

= 123

21

22

23

ddd

ddd

where, d3 = Shell Inside Diameter d2 = Coil Inside Diameter d1 = Coil Outside Diameter

4.3 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:

12

12

21

224

4

4

dd

dd

dd

perimeterwettedareationalcrossx

de

sec

(41)

where d2 = inside diameter of the outer pipe d1 = outside diameter of the inner pipe


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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 (42)

where, Q = heat transfer per unit time, W U = the overall heat transfer coefficient, W/m2°C A = heat transfer area, m2. Tm = 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,

12

21

1221

lntT

tTtTtT

Tlm

(44)

Tlm = log mean temperature difference T1 = inlet hot water temperature T2 = outlet hot water temperature t1 = inlet cold water temperature t2 = 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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14.0

4.065.0 PrRe26.0

w

f

f

ep

k

dh

(46)

where, hp = plate film coefficient.

epdG

Re (47)

and

f

p

k

C Pr (48)

where, Gp = mass flow rate per unit cross-sectional area = W/Af Af = cross-sectional area for flow de = equivalent (hydraulic) diameter = twice the gap between the plates Cp = fluid specific heat, heat capacity The flow arrangement in a plate heat exchanger is much closer to true counter-current 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:

28

2p

e

pfp

u

d

LjP

(49)

where, Lp = the path length up = Gp/. For preliminary calculations the following relationship can be used for turbulent flow:

3.0Re25.1 fj (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.


20

Figure 3: Single pass flow plate heat exchanger diagram


21

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. Switch off heater. Wait until the hot water temperature drops below 40°C. 2. Switch off pump P1 and pump P2. 3. Switch off main power. 4. 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.


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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)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

DPT1 (mmH2O)

DPT2 (mmH2O)

10 2 10 4 10 6 10 8 10 10

FT 1

(LPM) FT 2

(LPM) TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

DPT1 (mmH2O)

DPT2 (mmH2O)

2 10 4 10 6 10 8 10 10 10


23

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.


24

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


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)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

DPT1 (mmH2O)

DPT2 (mmH2O)

10 2 10 4 10 6 10 8 10 10

FT 1 (LPM)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

DPT1 (mmH2O)

DPT2 (mmH2O)

2 10 4 10 6 10 8 10 10 10


25

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.


26

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




Results:

FT 1 (LPM)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

5.0 2.0 5.0 3.0 5.0 4.0 5.0 5.0

FT 1

(LPM) FT 2

(LPM) TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

2.0 5.0 3.0 5.0 4.0 5.0 5.0 5.0

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

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




Results:

FT 1 (LPM)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

5.0 2.0 5.0 3.0 5.0 4.0 5.0 5.0

FT 1

(LPM) FT 2

(LPM) TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

2.0 5.0 3.0 5.0 4.0 5.0 5.0 5.0



28

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





Results:

FT 1 (LPM)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

10.0 2.0 10.0 4.0 10.0 6.0 10.0 8.0 10.0 10.0

FT 1 (LPM)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

2.0 10.0 4.0 10.0 6.0 10.0 8.0 10.0

10.0 10.0 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.


29

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





Results:

FT 1 (LPM)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

10.0 2.0 10.0 4.0 10.0 6.0 10.0 8.0 10.0 10.0

FT 1

(LPM) FT 2

(LPM) TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

2.0 10.0 4.0 10.0 6.0 10.0 8.0 10.0



30

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





Results:

FT 1 (LPM)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

8.0 2.0 8.0 4.0 8.0 6.0 8.0 8.0 8.0 10.0

FT 1

(LPM) FT 2

(LPM) TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

2.0 8.0 4.0 8.0 6.0 8.0 8.0 8.0



31

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




Results:

FT 1 (LPM)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

7.5 2.0 7.5 4.0 7.5 6.0 7.5 8.0 7.5 9.5

FT 1 (LPM)

FT 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

7.5 2.0 7.5 4.0 7.5 6.0 7.5 8.0 7.5 9.5



32

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.


33

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.

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

Experiment 2.B: Counter-Current Helical Coil Heat Exchanger

FI 1 (LPM)

FI 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°C)

FI 1 (LPM)

FI 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°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)

Experiment 3.B: Counter-Current Concentric Heat Exchanger

FI 1 (LPM)

FI 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°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)

Experiment 4.B: Counter-Current Plate Heat Exchanger

FI 1 (LPM)

FI 2 (LPM)

TT 1 (°C)

TT 2 (°C)

TT 3 (°C)

TT 4 (°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 Fahrenheit Kelvin Rankine

Temperature Kelvin Celcius Kelvin Celcius Kelvin

K = C + 273.15

C = 9

5 ( F – 32 )

C = 9

5 ( F – 459.67 )

C = 9

5 F – 273.15

C = 9

5 R

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

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 Fahrenheit Kelvin Rankine

Temperature Kelvin Celcius Kelvin Celcius Kelvin

K = C + 273.15

C = 9

5 ( F – 32 )

C = 9

5 ( F – 459.67 )

C = 9

5 F – 273.15

C = 9

5 R

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 μ x 103 (Pa.s)

0.0 273.2 999.6 4.229 0.5694 13.3 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 kg/m3

Heat capacity: 4175.00 J/kg.K

Thermal cond: 0.6436 W/m.K

Viscosity: 0.0005494 Pa.s

Cold water





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 10.0 10.0 10.0 9.9 9.8

Mass flow kg/s 0.1647 0.1647 0.1647 0.1630 0.1614

Inlet temp oC 50.8 50.8 51.0 51.4 51.2

Outlet temp oC 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

Cold fluid (Shell): Water


Mass flow kg/s 0.0332 0.0631 0.0929 0.1211 0.1510

Inlet temp oC 31.2 30.4 30.3 30.2 30.2

Outlet temp oC 40.7 37.3 35.8 34.9 34.3


Pressure drop mmH2O 35.50 116.30 238.40 400.20 over

Temp difference

Hot side inlet T, T1 oC 50.8 50.8 51 51.4 51.2

Hot side outlet T, T2 oC 48.6 47.9 47.6 47.4 47.1

Cold side inlet T, t1 oC 31.2 30.4 30.3 30.2 30.2

Cold side outlet T, t2 oC 40.7 37.3 35.8 34.9 34.3

T log mean, Tlm oC 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

Overall heat transfer coeff

Total exchange area m2 0.15 0.15 0.15 0.15 0.15

Overall heat transfer coeff W/m2.K 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 m2 0.0150 0.0150 0.0150 0.0150 0.0150

Number of tubes 10 10 10 10 10

Shell diameter mm 85 85 85 85 85

Baffle distance mm 50 50 50 50 50

Tube side

Cross section area m2 4.72E-05 4.72E-05 4.72E-05 4.72E-05 4.72E-05


Total cross section area m2 4.72E-04 4.72E-04 4.72E-04 4.72E-04 4.72E-04

Mass velocity kg/m2.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

Reynolds 4924.98 4924.98 4924.98 4875.73 4826.48

Prandtl 3.56 3.56 3.56 3.56 3.56

Type of flow turbulent turbulent turbulent turbulent turbulent

L/ID 64.52 64.52 64.52 64.52 64.52

Heat transfer factor, jh 3.90E-03 3.90E-03 3.90E-03 3.90E-03 3.90E-03

Tube coeff, hi W/m2.K 2426.16 2426.16 2426.16 2401.90 2377.64

Shell side

Cross flow area m2 2.00E-03 2.00E-03 2.00E-03 2.00E-03 2.00E-03



Equivalent diameter mm 27.78 27.78 27.78 27.78 27.78

Reynolds 575.88 1094.17 1612.46 2101.96 2620.25

Prandtl 5.44 5.44 5.44 5.44 5.44

Type of flow laminar laminar laminar turbulent turbulent

Baffle cut % 20 20 20 20 20


Shell coeff, hs W/m2.K 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


Hot water





Cold water





CALCULATIONS FOR SHELL AND TUBE (Co-Current)





Mass flow kg/s 0.1630 0.1630 0.1630 0.1630 0.1663

Inlet temp oC 51.1 51.1 51.3 51.2 51.2

Outlet temp oC 49.0 48.2 47.8 47.2 46.9


Pressure drop mmH2O 405.00 405.00 408.00 406.00 402.00



Mass flow kg/s 0.0332 0.0631 0.0929 0.1245 0.1527

Inlet temp oC 31.6 30.8 30.4 30.3 30.4

Outlet temp oC 40.2 36.8 35.4 34.5 34.1


Pressure drop mmH2O 35.40 117.00 233.00 411.30 over

Temp difference

Hot side inlet T, T1 oC 51.1 51.1 51.3 51.2 51.2

Hot side outlet T, T2 oC 49 48.2 47.8 47.2 46.9



T log mean, Tlm oC 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




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




Baffle distance mm 50 50 50 50 50

Tube side



Total cross section area m2 4.72E-04 4.72E-04 4.72E-04 4.72E-04 4.72E-04



Reynolds 4875.73 4875.73 4875.73 4875.73 4974.23

Prandtl 3.56 3.56 3.56 3.56 3.56


L/ID 64.52 64.52 64.52 64.52 64.52


Tube coeff, hi W/m2.K 2401.90 2401.90 2401.90 2401.90 2450.43

Shell side





Reynolds 575.88 1094.17 1612.46 2159.55 2649.04

Prandtl 5.44 5.44 5.44 5.44 5.44

Type of flow laminar laminar laminar turbulent turbulent

Baffle cut % 20 20 20 20 20



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


Hot water





Cold water





CALCULATIONS FOR SPIRAL HEAT EXCHANGER (Counter-Current)




Volumetric flowrate L/min 4.90 4.90 4.90 4.90

Mass flow kg/s 8.07E-02 8.07E-02 8.07E-02 8.07E-02

Inlet temp oC 51.00 51.00 51.10 51.10

Outlet temp oC 47.90 47.60 47.50 47.10

Heat transfer rate J/s 1044.48 1145.56 1212.94 1347.71



Mass flow kg/s 0.03 0.05 0.06 0.08

Inlet temp oC 31.10 30.90 30.60 30.60

Outlet temp oC 37.60 35.80 34.90 34.20

heat transfer rate J/s 947.51 1020.40 1104.39 1174.50

Temp difference

Hot side inlet T, T1 oC 51.00 51.00 51.10 51.10

Hot side outlet T, T2 oC 47.90 47.60 47.50 47.10

Cold side inlet T, t1 oC 31.10 30.90 30.60 30.60

Cold side outlet T, t2 oC 37.60 35.80 34.90 34.20

T log mean, Tlm oC 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


Total exchange area m2 0.15 0.15 0.15 0.15

Overall heat transfer coeff W/m2.K 420.96 427.68 445.84 469.83

Exchanger layout

Coil 1.00 1.00 1.00 1.00

Shell 1.00 1.00 1.00 1.00

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 m2 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

Cross section area m2 3.90E-05 3.90E-05 3.90E-05 3.90E-05

Mass velocity kg/m2.s 2067.34 2067.34 2067.34 2067.34

Linear velocity m/s 2.09 2.09 2.09 2.09

Reynolds 26528.53 26528.53 26528.53 26528.53

Prandtl 3.56 3.56 3.56 3.56

Type of flow turbulent turbulent turbulent turbulent

Tube coeff, hi W/m2.K 11047.45 11047.45 11047.45 11047.45

Shell side

Cross flow area m2 0.01 0.01 0.01 0.01



Equivalent diameter mm 39.54 39.54 39.54 39.54

Reynolds 339.97 485.67 598.99 760.88

Prandtl 5.44 5.44 5.44 5.44

Type of flow laminar laminar laminar laminar

Nusselt Number 4.26 5.67 6.71 8.12

Stanton Number 0.00230 0.00215 0.00206 0.00196

Heat transfer factor, jh 0.00717 0.00668 0.00640 0.00610

Shell coeff, hs W/m2.K 66.35 88.26 104.39 126.40

Experiment 2.B: Co-Current Spiral Heat Exchanger


Hot water





Cold water





CALCULATIONS FOR SPIRAL HEAT EXCHANGER (Co-Current)





Mass flow kg/s 0.08 0.08 0.08 0.08

Inlet temp oC 51.10 51.10 51.00 51.10

Outlet temp oC 48.20 47.50 47.00 46.90

Heat transfer rate J/s 997.03 1237.70 1375.22 1443.98



Mass flow kg/s 0.03 0.05 0.06 0.08

Inlet temp oC 32.30 31.90 31.80 31.60

Outlet temp oC 38.00 36.70 36.00 35.10

heat transfer rate J/s 791.33 932.93 1107.86 1166.17

Temp difference

Hot side inlet T, T1 oC 51.10 51.10 51.00 51.10

Hot side outlet T, T2 oC 48.20 47.50 47.00 46.90

Cold side inlet T, t1 oC 32.30 31.90 31.80 31.60

Cold side outlet T, t2 oC 38.00 36.70 36.00 35.10

T log mean, Tlm oC 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


Total exchange area m2 0.15 0.15 0.15 0.15

Overall heat transfer coeff W/m2.K 375.85 426.88 502.72 508.20

Exchanger layout

Coil 1.00 1.00 1.00 1.00

Shell 1.00 1.00 1.00 1.00

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 m2 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

Cross section area m2 0.00 0.00 0.00 0.00



Reynolds 27069.93 27069.93 27069.93 27069.93

Prandtl 3.56 3.56 3.56 3.56

Type of flow turbulent turbulent turbulent turbulent

Tube coeff, hi W/m2.K 11227.45 11227.45 11227.45 11227.45

Shell side

Cross flow area m2 0.01 0.01 0.01 0.01



Equivalent diameter mm 39.54 39.54 39.54 39.54

Reynolds 323.78 453.29 615.18 777.07

Prandtl 5.44 5.44 5.44 5.44

Type of flow 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

Shell coeff, hs W/m2.K 63.81 83.52 106.64 128.55

Experiment 3.A: Counter-Current Concentric Heat Exchanger


Hot water





Cold water





CALCULATIONS FOR CONCENTRIC HEAT EXCHANGER (Counter-Current)





Mass flow kg/s 0.15976 0.15811 0.15811 0.15976 0.15976

Inlet temp oC 51.10 51.10 51.10 51.10 51.10

Outlet temp oC 50.00 49.90 49.80 49.70 49.70




Mass flow kg/s 0.03319 0.06140 0.08961 0.11948 0.14769

Inlet temp oC 32.70 31.90 31.70 31.40 31.40

Outlet temp oC 35.30 33.70 33.20 32.70 32.60


Temp difference





T log mean, Tlm oC 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




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


Shell diameter mm 85.00 85.00 85.00 85.00 85.00

Tube side

Cross section area m2 0.000557 0.000557 0.000557 0.000557 0.000557



Reynolds 13897.73 13754.45 13754.45 13897.73 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


Stanton Number 0.00146 0.00146 0.00146 0.00146 0.00146

Heat transfer factor, jh 0.00341 0.00342 0.00342 0.00341 0.00341

Tube coeff, hi W/m2.K 1743.02 1728.63 1728.63 1743.02 1743.02

Shell side

Cross flow area m2 0.0048 0.0048 0.0048 0.0048 0.0048




Reynolds 445.74 824.62 1203.50 1604.67 1983.55

Prandtl 5.44 5.44 5.44 5.44 5.44

Type of flow laminar laminar laminar laminar laminar

Nuselt number 5.29 8.66 11.72 14.75 17.48

Stanton Number 0.00218 0.00193 0.00179 0.00169 0.00162

Heat transfer factor, jh 0.00679 0.00600 0.00557 0.00526 0.00504


Experiment 3.B: Co-Current Concentric Heat Exchanger


Hot water





Cold water





CALCULATIONS FOR CONCENTRIC HEAT EXCHANGER (Co-Current)





Mass flow kg/s 0.1548 0.1548 0.1581 0.1614 0.1598

Inlet temp oC 51.1 51.1 51.1 51.1 51.0

Outlet temp oC 49.7 49.7 49.7 49.7 49.6




Mass flow kg/s 0.0332 0.0614 0.0913 0.1195 0.1477

Inlet temp oC 32.6 31.8 31.7 31.6 31.6

Outlet temp oC 35.7 33.9 33.0 32.7 32.5


Temp difference

Hot side inlet T, T1 oC 51.1 51.1 51.1 51.1 51



Cold side outlet T, t2 oC 35.7 33.9 33 32.7 32.5

T log mean, Tlm oC 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




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 26.64 26.64 26.64 26.64 26.64

Tube OD mm 33.4 33.4 33.4 33.4 33.4



Tube side




Reynolds 13467.90 13467.90 13754.45 14041.00 13897.73

Prandtl 3.56 3.56 3.56 3.56 3.56

Nuselt number 70.36 70.36 71.55 72.74 72.15


Stanton Number 1.47E-03 1.47E-03 1.46E-03 1.45E-03 1.46E-03


Tube coeff, hi W/m2.K 1699.75 1699.75 1728.63 1757.38 1743.02

Shell side





Reynolds 445.74 824.62 1225.79 1604.67 1983.55

Prandtl 5.44 5.44 5.44 5.44 5.44

Type of flow laminar laminar laminar laminar laminar

Nuselt number 5.29 8.66 11.89 14.75 17.48

Stanton Number 2.18E-03 1.93E-03 1.78E-03 1.69E-03 1.62E-03



Experiment 4.A: Counter-Current Plate Heat Exchanger


Hot water





Cold water





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 7.18 7.18 7.18 7.18 7.18

Mass flow kg/s 0.11825 0.11825 0.11825 0.11825 0.11825

Inlet temp (calibrated temp) oC 50.5 50.5 50.5 50.5 50.5

Outlet temp (calibrated temp) oC 45.9 43.5 41.6 40.4 39.7


Cold fluid: Water Actual volume flow L/min 2.10 3.74 5.48 7.39 8.82

Mass flow kg/s 0.03485 0.06206 0.09094 0.12263 0.14636




Temp difference





T log mean, Tlm oC 6.21 7.34 7.87 8.18 8.24

Heat loss W 62.6 29.3 117.5 105.9 66.3

Efficiency % 97.3 99.2 97.3 97.9 98.8


Total plate area m2 0.092 0.092 0.092 0.092 0.092


Exchanger layout

Plate channel mm 1.29 1.29 1.29 1.29 1.29

No of plates 6 6 6 6 6

Plate width mm 71 71 71 71 71

Plate Length mm 308 308 308 308 308

Plate area m2 0.018 0.018 0.018 0.018 0.018

Cross sectional area m2 0.00009 0.00009 0.00009 0.00009 0.00009

Plate film coefficient (hot)

Total cross section m2 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



Reynolds 2021.02 2021.02 2021.02 2021.02 2021.02

Prandtl 3.56 3.56 3.56 3.56 3.56

Hot film coeff W/m2.K 15183.17 15183.17 15183.17 15183.17 15183.17

Plate film coefficient (cold)




Linear velocity, Gp m/s 0.1274 0.2269 0.3324 0.4483 0.5350

Reynolds 408.66 727.81 1066.41 1438.10 1716.38

Prandtl 5.44 5.44 5.44 5.44 5.44

Cold film coeff W/m2.K 6084.99 8854.91 11350.76 13785.94 15465.79

Experiment 4.B: Co-Current Plate Heat Exchanger


Hot water





Cold water





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




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




Temp difference





T log mean, Tlm oC 4.97 5.37 6.41 6.74 7.12

Heat loss W 28.28 9.51 183.12 48.62 62.24

Efficiency % 98.42 99.65 94.78 98.76 98.50


Total plate area m2 0.092 0.092 0.092 0.092 0.092


Exchanger layout

Plate channel mm 1.29 1.29 1.29 1.29 1.29

No of plates 6 6 6 6 6

Plate width mm 71 71 71 71 71

Plate Length mm 308 308 308 308 308

Plate area m2 0.018 0.018 0.018 0.018 0.018

Cross sectional area m2 0.00009 0.00009 0.00009 0.00009 0.00009

Plate film coefficient (hot)





Reynolds 1874.65 1874.65 1874.65 1874.65 1874.65

Prandtl 3.56 3.56 3.56 3.56 3.56

Hot film coeff W/m2.K 14459.05 14459.05 14459.05 14459.05 14459.05

Plate film coefficient (cold)




Linear velocity, Gp m/s 0.13 0.22 0.35 0.45 0.54

Reynolds 402.82 716.13 1117.01 1459.51 1728.06

Prandtl 5.44 5.44 5.44 5.44 5.44

Cold film coeff W/m2.K 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: 988.18 kg/m3 Heat capacity: 4175.00 J/kg.K Thermal cond: 0.6436 W/m.K Viscosity: 0.0005494 Pa.s Cold water Density: 995.67 kg/m3 Heat capacity: 4183.00 J/kg.K Thermal cond: 0.6155 W/m.K Viscosity: 0.0008007 Pa.s

Cold Water Flowrate = 2.0 LPM

COUNTER-CURRENT FLOW (Hot water inlet at 50'C)

Hot fluid (Tube-side): Water

Volume flow L/min 10.0

Inlet temp oC 50.8

Outlet temp oC 48.6

Cold fluid(Shell-Side): Water


Inlet temp oC 31.2

Outlet temp oC 40.7

SHELL AND TUBE HEAT EXCHANGER LAYOUT

Tube 1

Shell 1

Length of tubes m 0.5

Tube ID mm 7.75

Tube OD mm 9.53

Tube pitch mm 18

Tube surface area m2 0.015

Number of tubes 10

Shell diameter mm 85

Baffle length mm 50

Baffle Cut % 20

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.

W

CCkg

J

m

kg

sL

mL

TCmQ phhot

74.1512

)6.488.50(.

417518.98860

min1

1000

1

min0.10

(W) Hot Water,for RateTransfer Heat

3

3

W

CCkg

J

m

kg

sL

mL

TCmQ pccold

88.1318

)2.317.40(.

418367.99560

min1

1000

1

min0.2

(W) Water,Coldfor ReteTransfer Heat

3

3

%18.87%10074.1512

88.1318%100/Efficiency

86.19388.131874.1512 LostHeat

hotcold

coldhot

QQ

WQQRate

2. Calculation of Log Mean Temperature Difference:

C

inTcoutThoutTcinThToutThoutTcinThTlm

42.13

2.316.48

7.408.50ln

)2.316.48()7.408.50(

,,/,,ln/inc,,,,

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 = 4

πd 2i

= 4

00775.03.142 2

= 0.0000472 m2

Total cross Flow Area, At = 0.0000472 x number of tubes

= 0.0000472 x 10

= 0.000472 m2

Mass velocity, Gt = t

t

A

m

= 0.000472

0.1647

= 349.13 kg/m2.s

Linear Velocity, ut = ρ

Gt

= 988.18

349.13

= 0.3533 m/s

Renolds No, Re =

et dG

= 1000

1

0.0005494

75.713.349

= 4924.8 (Turbulent Flow)

Prandtl No, Pr = kCp

= 0.6436

41750005494.0

= 3.56

Tube side heat transfer factor, jh = 0.0039 (From Fig. C.2, Appendix C)

Tube Side Coefficient, hi = i

h

d

kj 33.0PrRe

= 0.00775

6436.056.398.49240.0039 0.33

= 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 = s

s

A

W

= 0.002

0.0332

= 16.60 kg/m2.s

Linear Velocity, us = ρ

Gs

= 995.67

16.60

= 0.0167m/s

Equivalent Diameter, de = 2o

2t

o

0.917dpd1.1

= 22 )0.917(9.53819.531.1

= 27.78 mm

Reynolds Number, Re =

es dG

= 1000

1

0.0008007

78.2760.16

= 575.88 (Laminar Flow)


= 0.6155

00.18340008007.0

= 5.44

Shell side heat transfer factor, jh = 0.023 (From Fig. C.4, Appendix C)

Shell Side Coefficient, hi = de

kjh 33.0PrRe

= 0.02053

6155.044.516.605023.0 0.33

= 513.18 W/m2.K

Overall heat transfer coefficient:

Total exchange area, A = Number of tube x x Tube OD x Length of Tubes

= 10 x x (9.53/1000) x 0.5

= 0.15 m2

Overall heat transfer coefficient, U = lm

hot

TA

Q

= 752.97 W/m2.K

4. Calculation of Pressure Drop across Tube and Shell

5.2)/(82

2

mwif

tpt dLj

uNP

= 5.2)00775.0/5.0(0058.082

3533.018.988 2

= 338.8 Pa

14.02

2)/)(/(8 w

sBesfs

ulLdDjP

Pa

Ps

3.3

0.12

)0167.0)(67.995(

05.0

5.0

02778.0

085.0)098.0)(8( 14.0

2

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: 988.18 kg/m3 Heat capacity: 4175.00 J/kg.K Thermal cond: 0.6436 W/m.K Viscosity: 0.0005494 Pa.s Cold water Density: 995.67 kg/m3 Heat capacity: 4183.00 J/kg.K Thermal cond: 0.6155 W/m.K Viscosity: 0.0008007 Pa.s





Inlet temp oC 51.0

Outlet temp oC 47.9



Inlet temp oC 31.1

Outlet temp oC 37.6

SPIRAL HEAT EXCHANGER LAYOUT Coil 1

Shell 1

Length of tubes m 5

Tube ID mm 7.05

Tube OD mm 9.53

Coil surface area m2 0.15


Coil ID mm 34

Coil OD mm 44


The Heat Transfer rate of both hot and cold water are both calculated using the heat balance equation.

W

CCkg

Jm

kg

sL

mL

TCmQ phhot

48.1044

)9.470.51(.

4175

18.98860

min1

1000

1

min90.4


3

3

W

CCkg

Jm

kg

sL

mL

TCmQ pccold

51.947

)1.316.37(.

4183

67.99560

min1

1000

1

min1.2


3

3

%72.90%10048.1044


97.9651.94748.1044 LostHeat

hotcold

coldhot

QQ

WQQRate


C


04.15

1.319.47

6.370.51ln

)1.319.47()6.370.51(

,,/,,ln/inc,,,,

3. Calculation of the tube and shell heat transfer coefficients by Kern’s method: Assuming, Tm = Tlm


Cross Flow Area, At = 4

πd 2i

= 4

00705.03.142 2

= 0.000039 m2


t

A

m

= 0.000039

0.0807

= 2067.34 kg/m2.s


Gt

= 988.18

2067.34

= 2.09 m/s

Renolds No, Re =

et dG

= 1000

1

0.0005494

05.734.2067



= 0.6436

41750005494.0

= 3.56

Tube Side Coefficient, hi = ed

k33.08.0 PrRe023.0

= 0.00705

6436.056.353.26528023.0 0.338.0

= 11047.45Wm-2K


Cross Flow Area, As = 21

22

234

DDD

= 222 033.0044.0085.04

= 0.00506 m2


s

A

W

= 0.005060.0332

= 6.88kg/m2.s


Gs

= 995.67

6.88

= 0.00691m/s

Equivalent Diameter, de =

321

21

22

23

ddd

ddd

=

344485344485 222

= 39.54 mm


es dG

= 1000

1

0.0008007

54.3988.6


Prandtl Number, Pr = kCp

= 0.6155

00.18340008007.0

= 5.44

Nuselt Number, Nu = 33.08.0 PrRe023.0

= 33.08.0 44.597.339023.0

= 4.26

Stanton Number, St = PrRe

Nu

= 44.597.339

27.4

= 0.00230

Heat transfer factor, jh = 67.0PrSt

= 67.044.500230.0

= 00717.0

Shell Side Coefficient, hs = de

kjh 33.0PrRe

= 0.03954

6155.044.597.33900717.0 0.33

= 66.35W/m2.K


Total exchange area, A = x (0.00953/1000) x 5.0

= 0.15 m2


hot

TA

Q

= 420.96 W/m2.K

4. Temperature Profile for counter-current Spiral Heat Exchanger


Sample Calculation for Concentric Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density: 988.18 kg/m3 Heat capacity: 4175.00 J/kg.K Thermal cond: 0.6436 W/m.K Viscosity: 0.0005494 Pa.s Cold water Density: 995.67 kg/m3 Heat capacity: 4183.00 J/kg.K Thermal cond: 0.6155 W/m.K Viscosity: 0.0008007 Pa.s





Inlet temp oC 51.1

Outlet temp oC 50.0



Inlet temp oC 32.7

Outlet temp oC 35.3

SHELL AND TUBE HEAT EXCHANGER LAYOUT Tube 1

Shell 1

Length of tubes m 0.5

Tube ID mm 26.64

Tube OD mm 33.4

Tube surface area m2 0.0525



The Heat Transfer rate of both hot and cold water are both calculated using the heat balance equation.

W

CCkg

Jm

kg

sL

mL

TCmQ phhot

68.733

)0.501.51(.

4175

18.98860

min1

1000

1

min70.9


3

3

W

CCkg

Jm

kg

sL

mL

TCmQ pccold

96.360

)7.323.35(.

4183

67.99560

min1

1000

1

min0.2


3

3

%20.49%10068.733


72.37296.36068.733 LostHeat

hotcold

coldhot

QQ

WQQRate


C


54.16

7.320.50

3.351.51ln

)7.320.50()3.351.51(

,,/,,ln/inc,,,,

3. Calculation of the tube and shell heat transfer coefficients by Kern’s method: Assuming, Tm = Tlm


Cross Flow Area, At = 4

πd 2i

= 4

02664.03.142 2

= 0.000557 m2


t

A

m

= 0.000557

0.1597

= 286.61 kg/m2.s


Gt

= 988.18

286.61

= 0.29004 m/s

Renolds Number, Re =

et dG

= 1000

1

0.0005494

64.2661.286



= 0.6436

41750005494.0

= 3.56


= 33.08.0 56.373.13897023.0

= 72.15


Nu

= 56.373.13897

15.72

= 0.00146


= 67.056.300146.0

= 0.00341

Tube Side Coefficient, hi = id

k33.08.0 PrRe023.0

= 0.02664

6436.056.373.13897023.0 0.338.0

= 1743.02 Wm-2K


Cross Flow Area, As = 22

4 os dD

= 0.0048 m2


s

A

W

= 0.0048

0.0332

= 6.917 kg/m2.s


Gs

= 995.67

6.917

= 0.00695 m/s

Equivalent Diameter, de = 12 dd

= 4.330.85

= 51.6 mm


es dG

= 1000

1

0.0008007

6.51917.6



= 0.6155

00.18340008007.0

= 5.44


= 33.08.0 44.574.445023.0

= 5.29


Nu

= 44.574.445

29.5

= 0.00218


= 67.044.500218.0

= 0.00679

Shell Side Coefficient, hs = de

kjh 33.0PrRe

= 0.0516

6155.029.574.44500679.0 0.33

= 63.15 W/m2.K


Total exchange area, A = x Tube OD x Length of Tubes

= x (26.64/1000) x 0.5

= 0.05 m2


hot

TA

Q

= 845.55 W/m2.K

4. Temperature Profile for counter-current Shell and Tube Heat Exchanger


Sample Calculation for Plate Heat Exchanger TYPICAL CHEMICAL DATA Hot water Density: 988.18 kg/m3 Heat capacity: 4175.00 J/kg.K Thermal cond: 0.6436 W/m.K Viscosity: 0.0005494 Pa.s Cold water Density: 995.67 kg/m3 Heat capacity: 4183.00 J/kg.K Thermal cond: 0.6155 W/m.K Viscosity: 0.0008007 Pa.s





Inlet temp oC 50.5

Outlet temp oC 45.9



Inlet temp oC 32.9

Outlet temp oC 48.2

PLATE HEAT EXCHANGER LAYOUT

Total cross section area m2 0.000275

Plate width mm 71

Plate length mm 308

Plate channel mm 1.29

No. of plate 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.

W

CCkg

Jm

kg

s

m

TCmQ phhot

2.2298

)9.455.50(.

4175

18.98860

min1

min1000

18.7

(W) Hot Water,for ratefer heat trans

3

3

W

CCkg

Jm

kg

s

m

TCmQ pccold

6.2235

)9.322.48(.

4183

67.99560

min1

min1000

10.2

(W) Water,Coldfor ratefer Heat trans

3

3

%3.97%1002.2298


6.626.22352.2298 =LostPower

coldhot

coldhot

QQ

WQQ


C


21.6

9.329.45

2.485.50ln

)9.329.45()2.485.50(

,,/,,ln/inc,,,,

3. Calculation of the hot and cold plate heat transfer coefficients: Heat Transfer Coefficient at Hot Plate

Mass Velocity = AreaSectionCrossTotal

RateFlowMass

= 2m0

s0.11825kg/000275.

= 430.37 kg/m2.s

Linear Velocity = Density

VelocityMass

= 3

2

mkg/9skg/m

18.88

37.430

= 0.4355 m/s Equivalent Diameter, de = depth2 = 2 x 0.00129 = 0.00258 m

Reynolds No = viscocity

deVelocity Mass

= Pa.s0.00054940.00258ms30.37kg/m2 4

= 2021.02

Prandtl No = tyConductiviThermal

ViscocityCapacityHeat

= W/m.s0.6436

Pa.s0.0005494CJ/kg.00.1754

= 3.56

Plate Film Coefficient at Hot Side, hpH = de

kPrRe0.26 0.40.65

= 0.00258

0.64363 0.26 0.40.65 56.02.2021 x

= 15183.17 W/m2.K Heat Transfer Coefficient at Cold Plate

Mass Velocity = AreaSectionCrossTotal

RateFlowMass

= 2m0

kg/s

000275.

03485.0

= 126.8277 kg/m2.s

Linear Velocity = Density

VelocityMass

= 3

2

mkg/995.67

skg/m126.8277

= 0.1274 m/s

Reynolds No = viscocity

deVelocity Mass

= Pa.s0.00080071

m0skg/m126.8277 2 00258.

= 408.66

Prandtl No = tyConductiviThermal

ViscocityCapacityHeat

= W/m.s6155.0

Pa.s0008007.0CJ/kg.00.1834

= 5.44

Plate Film Coefficient at Cold Side, hpC = de

kPrRe0.26 0.40.65

= 0.00258

.50.26 0.40.65 6155044.66.408

= 6084.99W/m2.K

4. Temperature profile for counter-current Plate Heat Exchanger


APPENDIX F

TEMPERATURE SENSOR CALIBRATION

Temperature Sensor Calibration Table

Actual Temperature Sensor Temperature

T1 T2 T3 T4

30 30.0 29.7 30.0 29.2

35 35.0 34.8 35.0 34.0

40 40.0 39.7 40.0 39.7

45 44.8 44.6 45.0 44.6

50 49.6 49.5 49.7 49.4

55 54.5 54.4 54.8 54.5

60 59.7 59.6 60.0 59.5

65 64.0 64.4 64.8 64.4

70 69.6 69.5 69.8 69.4

75 74.5 74.4 74.8 74.4

80 79.6 79.4 79.8 79.2

85 84.2 84.4 84.6 84.2

90 88.8 89.5 89.3 89.0

slope 0.9920 0.9924 0.9965 0.9898

correcting factor for the calibrated sensor temperature

1.0081 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.

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