HE158C EXPERIMENTAL MANUAL.pdf

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EXPERIMENTAL MANUAL

MODEL: HE158C

SOLUTION ENGINEERING SDN. BHD.

NO.3, JALAN TPK 2/4, TAMAN PERINDUSTRIAN KINRARA, 47100 PUCHONG, SELANGOR DARUL EHSAN, MALAYSIA.

HEAT EXCHANGER

TRAINING

APPARATUS

HEAT EXCHANGER

TRAINING

APPARATUS

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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

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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

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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

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Table 1 Valves Arrangement for Flow Selection 5

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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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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

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

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

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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

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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

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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

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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.

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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 t2 ΔT2 T1 Heat Transfered Fluid Temp. t1 t2 t1, mt ΔT1

Figure 2a: Temperature profile for a parallel-flow heat exchanger.

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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 AiTm (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:

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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 2 1 ln T _T T T Tlm (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: ) ( ) ( 1 2 2 1 t t T T R    and, ) ( ) ( 1 1 1 2 t T t t 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 . 0 33 . 0 8 . 0 _Pr ₍ _/ ₎ Re _f _w C Nu   (9) where, Re = Reynolds Number = _fu_td_e/_fG_td_e/_f Nu = Nusselt Number = h_id_e/ k_f Pr = Prandtl Number = C_p_f /k_f

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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

f

k = Fluid thermal conductivity (W/m°C)

For laminar flow (Re < 2000), the following correlation is used:





0.14 33 . 0 33 . 0 ₍ _/ ₎ Pr) . (Re 86 . 1 de L f w Nu   (10) where,

L = the tube length (m)

Tube-side Pressure Drop,Pt

The tube-side pressure drop is given by:









2 5 . 2 ) / ( 8 2 t f m w i f p t u d L j N P       ₍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)

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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:



2 2



2 2 785 . 0 27 . 1 ) 4 / ( 4 o t o o o t e d p d d d p d       (15)

(For square pitch arrangement)



2 2



2 917 . 0 10 . 1 2 / 4 / 2 1 87 . 0 2 4 o t o o o t t e d p d d d p p 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:





0.14 33 . 0 Pr Re / f h f w e sd k j h Nu    (18)

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Shell-side Pressure Drop, Ps (Kern’s Method)

The shell-side pressure drop is given by:





0.14 2 2 ) / )( / ( 8    s _f _w B e s f s u l L d D j P    (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:

L b w n oc s h F F F F h  (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,

_Re_Pr0.33₍ ₎0.14 w f h f o oc _j k d h _ _  (21) where, Re = Gs do/ µf = us do ρ f / µf

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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,

exp



1



2 /



13



for /2 cv s cv s s b b _A N N N N A F _           (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,

FL1L





Atb 2Asb



/AL



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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. L b i c PFF P     (24) where,

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

2

u 

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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

b

F = by-pass correction factor,

L

F = leakage correction factor.

Calculate F from Equation 21 with _b  = 5.0 for laminar region, Re < 100 and  = 4.0 for transition and turbulent region, Re > 100. If no sealing strips used, take

b

F from Figure C.12.

Calculate FL from Equation 22 taking L from Figure C.13.

The window-zone pressure drop is, 2 ) 6 . 0 2 ( 2 z wv L w F N u P      (26) where,

uz = geometric mean velocity, = uwus

uw = velocity in the window zone = W_s A_w ,

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,







wv cv cv



b i e P N N N F P    (27)

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

w b c b e b b s P N P N P N N P          ) 1 ( 2 = zones) (window + zones) (crossflow ) 1 ( + zones) 2(end (28) where, Nb = number of baffles = (L/ lB – 1) (29)

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Bb = “bundle cut” = Hb / Db,

b = angle subtended by the baffle chord (rads),

Db = bundle diameter Subsequently, ) 5 . 0 ( 2 / _s _c b b D D B H    (30) t b b cv D H p N ( 2 )/  (31) t b wv H p N  / (32) 

where p _t = 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:

a t

w N R

N    (33)

where R can be obtained from Figure C.15, for the appropriate “bundle cut”, B_a b.

The number of tubes in a cross-flow zone Nc is given by,

Nc=Nt – 2 Nw (34) and Rw=2 Nw / Nt (35)



( 2 4)

 

( 2 4)



o w s a w R D N d A       (36)

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

) ( ) 2 ( _t _o _t _w tb c d N N A    (37)

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

) 2 ( ) 2 ( _s _s _b sb c D A    (38)

where cs is the baffle-to-shell clearance and θb can be obtained from Figure C.15

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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 = perimeter wetted area tional cross sec  4 (40) =







3 2 1



2 1 2 2 2 3 4 4 d d d d d d         _ _    =



_

_



1 2 3 2 1 2 2 2 3 d d d d d d     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:









1 2 1 2 2 1 2 2 4 4 4 d d d d d d perimeter wetted area tional cross x d_e          _      sec (41) where

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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,



 









2 1



2 1 1 2 2 1 ln t T t T t T t T 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

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14 . 0 4 . 0 65 . 0 _Pr Re 26 . 0 _       w f f e p k d h   (46) where,

hp = plate film coefficient.  e pd G  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: 2 8 2 p e p f p u d L j P _        (49) where,

Lp = the path length up = Gp/.

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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.

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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) (LPM) FT 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C) (mmHDPT1 2O) DPT2 (mmH2O) 10 2 10 4 10 6 10 8 10 10 FT 1 (LPM) (LPM) FT 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C) (mmHDPT1 2O) DPT2 (mmH2O) 2 10 4 10 6 10 8 10 10 10

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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.

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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:

2. Switch the valves to co-current Shell & Tube Heat Exchanger arrangement (Please refer to Section 2.3).

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.

Results: FT 1 (LPM) (LPM) FT 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C) (mmHDPT1 2O) DPT2 (mmH2O) 10 2 10 4 10 6 10 8 10 10 FT 1 (LPM) (LPM) FT 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C) (mmHDPT1 2O) DPT2 (mmH2O) 2 10 4 10 6 10 8 10 10 10

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Assignments:

4. Calculate the pressure drop and compare with the experimental result. 5. Perform temperature profile study and the flow rate effects on heat transfer.

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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:

2. Switch the valves to counter-current Spiral Heat Exchanger arrangement (Please refer to Section 2.3).

Results: FT 1 (LPM) (LPM) FT 2 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) (LPM) FT 2 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:

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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:

2. Switch the valves to co-current Spiral Heat Exchanger arrangement (Please refer to Section 2.3).

Results: FT 1 (LPM) (LPM) FT 2 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) (LPM) FT 2 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

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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:

2. Switch the valves to counter-current Concentric Heat Exchanger arrangement (Please refer to Section 2.3).

Results: FT 1 (LPM) (LPM) FT 2 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) (LPM) FT 2 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:

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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:

2. Switch the valves to co-current Concentric Heat Exchanger arrangement (Please refer to Section 2.3).

Results: FT 1 (LPM) (LPM) FT 2 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) (LPM) FT 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C) 2.0 10.0 4.0 10.0 6.0 10.0

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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:

2. Switch the valves to counter-current Plate Heat Exchanger arrangement (Please refer to Section 2.3).

Results: FT 1 (LPM) (LPM) FT 2 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) (LPM) FT 2 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 10.0 8.0 Assignments:

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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:

2. Switch the valves to co-current Plate Heat Exchanger arrangement (Please refer to Section 2.3).

Results: FT 1 (LPM) (LPM) FT 2 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) (LPM) FT 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C) 7.5 2.0 7.5 4.0

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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.

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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.

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APPENDIX A

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FI 1

(LPM) (LPM) FI 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C) (mmHDPT1 2O)

DPT2 (mmH2O)

Experiment 1.B: Counter-Current Shell & Tube Heat Exchanger

FI 1

(LPM) (LPM) FI 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C) (mmHDPT1 2O)

DPT2 (mmH2O)

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

FI 1

(LPM) (LPM) FI 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C) FI 1

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FI 1

(LPM) (LPM) FI 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C)

Experiment 3.B: Counter-Current Concentric Heat Exchanger

FI 1

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FI 1

(LPM) (LPM) FI 2 TT 1 (°C) TT 2 (°C) TT 3 (°C) TT 4 (°C)

Experiment 4.B: Counter-Current Plate Heat Exchanger

FI 1

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APPENDIX B CONVERSION FACTORS

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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 = 5 R 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 = 5 R

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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) Speed Meter/ second Meter/ second Meter/ second 0.3048 0.27777778 0.51444444

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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

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T (ºC) T (K) ρ (kg/m3_{) c}_p_{(kJ/kg.K) k}_(W/m.K) _N_Pr μ x 10 (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

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APPENDIX C

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APPENDIX D RESULTS SUMMARY

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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

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

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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

Mass velocity kg/m2.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 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

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CALCULATIONS FOR SHELL AND TUBE (Co-Current) Fixed Hot water flow rate at 10 LPM

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

Number of tubes 10 10 10 10 10

Shell diameter mm 85 85 85 85 85

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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

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

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 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

Shell coeff, hs W/m2.K 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

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CALCULATIONS FOR SPIRAL HEAT EXCHANGER (Counter-Current) Fixed Hot water flow rate at 5 LPM

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

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Mass velocity kg/m2.s 6.88 9.83 12.13 15.41

Linear velocity m/s 0.00691 0.00988 0.01218 0.01548

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

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CALCULATIONS FOR SPIRAL HEAT EXCHANGER (Co-Current) Fixed Hot water flow rate at 5 LPM

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

(74)

Mass velocity kg/m2.s 6.56 9.18 12.46 15.74

Linear velocity m/s 0.01 0.01 0.01 0.02

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

(75)

CALCULATIONS FOR CONCENTRIC HEAT EXCHANGER (Counter-Current) Fixed Hot water flow rate at 10 LPM

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

Hot side inlet T, T1 oC 51.10 51.10 51.10 51.10 51.10

Hot side outlet T, T2 oC 50.00 49.90 49.80 49.70 49.70

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

(76)

Cross flow area m2 0.0048 0.0048 0.0048 0.0048 0.0048 Mass velocity kg/m2.s 6.917 12.796 18.675 24.900 30.780 Linear velocity m/s 0.00695 0.01285 0.01876 0.02501 0.03091 Equivalent diameter mm 51.60 51.60 51.60 51.60 51.60 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