Small Shell and Tube Heat Exchanger Final Report ChE 0101 ...ljb59/shellandtube.pdf · Small Shell and Tube Heat Exchanger Final Report ChE 0101 Group A-4 By: Aaron Guche, Caleb Hefright,

Small Shell and Tube Heat Exchanger

Final Report

ChE 0101 Group A-4

By: Aaron Guche, Caleb Hefright, Farhan Ahmed, Patrick Flaherty, Jean Fiore, Luke Barone,

Tanner Boyle

12/5/2016

1

Table of Contents

Page

Nomenclature . . . . . . . . . . . 2

1.0 Introduction and Background . . . . . . . . 3

2.0 Experimental Methodology . . . . . . . . 6

2.1 Experiment and Apparatus

2.2 Experimental Procedures

3.0 Results . . . . . . . . . . . 8

4.0 Analysis and Discussion of Results . . . . . . . 12

5.0 Summary and Conclusion . . . . . . . . . 14

6.0 Appendix . . . . . . . . . . . 16

6.1 Steady State Data for All Trials

6.2 Sample Calculations

7.0 References. . . . . . . . . . . 29

2

Nomenclature

Variable Definition Units

M Mass flow rate of the system kg/min

Cp Specific heat capacity of water J/g°C

ΔT Temperature change that occurs °C

within a single fluid

Qloss Measure of how much heat energy W

has been lost within a system

U Overall heat transfer coefficient W/m2°C

ΔTlm Average temperature change that °C

occurs between two fluids

F Correction Factor .96

A Heat transfer surface area m2

3

1.0 Introduction and Background

Heat exchangers are a vital part of chemical engineering process designs. To illustrate, in

prototype testing, an inventor discovers that his new device is prone to overheating, even though

heat sinks are already installed to provide cooling to the system. To solve this problem, the

engineer decides to install a heat exchanger into the system. A heat exchanger is a device that is

commonly used when heat sinks alone cannot prevent a device from overheating [1]. The most

well-known application of heat exchangers are car radiators. Radiators use antifreeze to transfer

heat energy from the engine, to the air surrounding the car [1].

There are many different types of heat exchangers, each having various applications. Three

examples include regenerative, plate, and shell and tube heat exchangers. Regenerative heat

exchangers are a unique type of heat exchanger that are used to maintain a temperature, rather than

vary it. In order to achieve this, initial thermal energy from a fluid is used to reheat that same fluid

as it loses its thermal energy throughout the process. Due to the nature of this heat exchanger, very

little external energy is required to maintain the overall temperature of the heat exchanger.

Conversely, plate heat exchangers have many thin plates inside with small gaps between each

plate. Alternating fluid then flows through each gap, causing the two fluids to exchange thermal

energy. This type of heat exchanger can be used to either cool, or heat a fluid. Plate heat exchangers

are commonly used in household refrigerators [2]. Similar to a plate heat exchanger, a shell and

tube heat exchanger utilizes two separate fluids to transfer thermal energy from one to the other.

To achieve this, one fluid is routed through a tube inside a hollow shell. The shell has the second

fluid flowing through it, allowing heat to transfer between the two.

Shell and tube heat exchangers are used widely in many different chemical processes

because of their numerous advantages. Shell and tube heat exchangers are capable of having a

large surface area for heat transfer to take place. This is because of their numerous tubes. This

design also minimizes the necessary overall length [3]. Shell and tube heat exchangers also offer

a lot of versatility when it comes to operating pressure and temperature. Since there are limited

pressure and temperature restrictions, small shell and tube heat exchangers can accommodate a

higher heat duty. This is because additions can be made to neglect thermal expansion effects as

well as variations to the thickness of the exchanger [4]. From a design perspective, the thickness

4

is easily varied, making them very adaptable. The number of tubes and different types of baffles

needed can be designed and implemented based off of specific operation conditions [4].

One of the main concerns with shell and tube heat exchangers is they are susceptible to

vibration problems caused from the fluid flowing throughout the pipes. Although the baffles

within the system help hold these tubes in place to reduce vibrations, problems can still arise [3].

Another concern is the maintenance of the tubes, which can be difficult. Because of this, fouling

can occur. Buildup can greatly affect the overall heat transfer coefficient and efficiency of the unit

[3]. When assessing these issues, observations of the heat energy gained or lost by the system must

be accomplished. For this experiment the equation used to determine this energy is

Q=MCpΔT.

(1)

M is the mass flow rate of the water, and is a measure of the flow of water into the system. In order

for proper calculations, data must be collected when the system is at steady state. Cp is the specific

heat capacity of the material, which is the amount of energy per unit mass required to raise the

temperature of a substance by one degree. ΔT is the change in temperature of the fluid throughout

the system.

This calculation is done for the cold and hot side of the heat exchanger to obtain Qcold and

Qhot. To determine the efficiency of the unit, the equation

Qhot= Qcold + Qloss

(2)

can be used to determine Qloss. This quantity will determine how much heat has been lost during

the experiment. Since the shell-side is the hot side, some of the energy escapes through conduction

to the outside environment, contributing to this value. For an efficient system, Qloss should be

minimized.

Another calculation used when analyzing heat exchange is calculating heat transfer

between two elements. The equation used is

Q = UAΔTlmF.

(3)

5

U is the overall heat transfer coefficient. This heat transfer coefficient is a function of the fluid

properties and material composition of the heat exchanger. U varies based on the design of the

heat exchanger. Q in this equation is calculated from Equation 1, and is the energy gained or lost

by the system. F is a correction factor that must be used for this heat exchanger to accommodate

for concurrent or parallel flow in the heat exchanger. In opposition, counter current flow occurs

when the streams are flowing in opposite directions. This leads to a constant flow of heat at each

point of contact and a higher rate of heat transfer. For this heat exchanger F is 0.96. A is the heat

transfer surface area for the tubes which is 50 square inches. ∆Tlm is the log mean temperature

difference and can be calculated by using the equation

(∆T2-∆T1)/ln(∆T2/∆T1)

(4)

where ∆T1 and ∆T2 are

∆T2 = T(hot, in) - T(cold,out),

(5)

and

∆T1 = T(hot,out) - T(cold,in).

(6)

The log mean temperature difference is unlike the other ∆T’s calculated in previous equations. It

is the temperature difference between two streams. In previous calculations, ∆T was simply the

temperature change over each single stream analyzed. Since in the system, temperatures are

constantly changing along a path, the log mean temperature difference is used to give an average

temperature gradient.

The two technical objectives of the experiment are to evaluate the effect of the tube-side

flow rate and shell-side flow rate on the steady-state heat duty and the overall heat transfer

coefficient of the heat exchanger. To accomplish this, flow rates were adjusted on one side, while

keeping the other side constant. The data used from steady state was used to determine how a

difference in flow rate affected the calculated values.

6

2.0 Experimental Methodology

2.1 Experiment and Apparatus:

The apparatus used in the experiment was a small shell and tube heat exchanger, as

shown in Figure 1.

Figure 1. Diagram of a Shell and Tube Heat Exchanger

In Figure 1, the arrows labeled hot flow in/out denote the direction the hot side fluid flowed

throughout the shell of the apparatus. A baffle within the system influenced the flow of the

fluid through the shell to ensure that proper mixing occurred to maximize heat transfer.

The arrows labeled cold flow in/out depict the flow of the cold side fluid through a bundle

of tubes that travels in an s-shaped pattern before exiting the heat exchanger. Additionally,

not depicted in Figure 1 but essential to the experiment is a pump for both the hot and cold

fluids, valves to control the flow rate of the fluid, a heater to heat the hot side fluid, and a

chiller to cool the cold side fluid.

Figure 2. Apparatus and computational equipment

Shell and

tube

Tubes for

hot side

flow

Pump for

hot side

fluid

Computer for

computational

purposes

Heater for

hot side

fluid

Hot side flow

control valve

Cold side flow

control valve

7

2.2 Experimental Procedures:

To begin experimentation with the small shell and tube heat exchanger, the proper

apparatus was set up in accordance with the LabVIEW software provided. First, the

chiller was set at 20 degrees Celsius and power to all components on the heat exchanger

panel were turned on. To complete the first technical objective, the tube-side flow was

varied. Initially, the tube-side valve was set at 10% open and the shell-side valve was set

at 50% open. After allowing the outlet temperatures of both the tube and shell-sides to

stabilize and reach steady state, the tube-side valve setting was varied, allowing it to

reach steady state again. Steady state was achieved when the data plots showed that the

temperatures of the corresponding data plots were level and ceased to change. This was

repeated two more times and the valve settings and temperature data are summarized in

Table 1. To evaluate technical objective two, the shell and tube valves were initially set

again. However, this time, the shell-side flow rate was varied. The procedure settings are

displayed in Table 1.

Table 1. Technical Objectives 1 & 2 Settings and Variables (Respectively)

Shell-side Valve

Setting

Tube-side Valve

Setting

Chiller Temperature (ºC)

50% 10% 20

50% 30% 20

50% 60% 20

50% 100% 20

Shell-side Valve

Setting

Tube-side Valve

Setting

Chiller Temperature (ºC)

10% 50% 20

30% 50% 20

50% 50% 20

70% 50% 20

8

3.0 Results

Two separate trials were conducted in this experiment, one varying the tube-side (cold side)

flow rate, and the other varying the shell-side (hot side) flow rate. In the first trial, the tube-side

flow rate was gradually increased, and the results have been presented in Table 2.

Table 2. Tabulated heat duties, log mean temperature differences, and heat transfer coefficients

when varying the tube-side valve opening.

% Valve

open

Qc (W) Qh (W) QL (W) ΔTlm

(°C)

U (W/m^2*°C)

10% 905 1653 748 18.98 1542.7

30% 926 1685 759 15.80 1895.3

60% 925 1668 743 14.12 2119.6

100% 929 1669 739 13.63 2206.5

One important observation made from the data in Table 2 was that the amount of heat lost

from the system (QL) was roughly constant no matter how much the flow rate was increased on

the tube-side. Each time the valve opening was increased, the amount of heat lost per minute stayed

constant at about 745 W. Another interesting result can be found by examining the log-mean

temperature difference, which represents the temperature differential between the two fluids in the

system. As the valve opening on the tube-side increased, the temperature difference decreased

representing an inverse relationship. This means that as the cold side flow rate increased, the two

fluids became closer in temperature. Finally, it was also noticed that as the tube-side flow rate was

increased the overall heat transfer coefficient (U) increased significantly. This was because the

surface area of the tubes and the correction factor were constant during each trial. Additionally,

the heat duty of the cold side (Qc) was also relatively constant. Therefore, the only varying quantity

in the calculation of the heat transfer coefficient was the log-mean temperature difference. In order

to evaluate the effect of the tube-side flow rate on the heat transfer coefficient, these values were

plotted against each other in Figure 3. From Figure 3 it can be seen that a power curve is a very

good fit for the data with an R2 value of 0.9988.

9

Figure 3. Overall heat transfer coefficient vs. tube-side flow rate.

In the second trial, the tube-side flow rate (cold side) was held steady while the shell-side

(hot side) flow rate was varied. This trial yielded some results very similar to those found when

varying the tube-side flow rate but also produced some new trends. The data for the shell-side trial

is presented in Table 3.


when varying the shell-side valve opening.

% Valve

Open


(°C)

U (W/m^2*C)

10% 829 1452 624 18.27 1467.4

30% 894 1574 681 15.67 1844.8

50% 897 1640 744 14.25 2035.2

70% 902 1660 758 13.52 2157.6

After examining the data in Table 3 it was found that the heat duties for both the cold side

and hot side were not similar as in the first trial. Instead the heat duties for both sides increased as

the shell-side flow rate increase. In particular, the heat duty for the hot side increased more than

y = 220.77x0.271

R² = 0.9988

0.0

500.0

1000.0

1500.0

2000.0

2500.0

0 1000 2000 3000 4000 5000 6000

U (

kW/m

2*°

C)

ṁc (g/min)

10

that for the cold side. However, when looking at the log-mean temperature difference, very similar

results were observed in both trials. After comparing the data in Table 2 and Table 3, it was noticed

that the ΔTlm values varied only within a few tenths of a degree Celsius between the two trials.

This means that the temperature difference between the two fluids in each trial was about the same

no matter whether the tube-side or shell-side flow was altered. Finally, the trend that the heat

transfer coefficient increased as the shell-side flow rate increased was also seen in Table 3. This

matches the trend found in the first trial. The interesting part of this result was that the overall heat

transfer coefficients were slightly lower when increasing the shell-side flow rate rather than the

tube-side flow rate. Figure 4 plots the heat transfer coefficient dependent on the shell-side flow

rate. The data for this trial was best represented using a logarithmic relationship resulting in an R2

value of 0.988.

Figure 4. Overall heat transfer coefficient vs. shell-side flow rate.

A third and final trial was conducted, varying the shell-side flow rate again while keeping

the tube-side flow rate steady, to see if the data could be repeated for accuracy. This trial

produced very similar results to those found in trial two which was encouraging. The data for

trial three has been presented in Table 4.

y = 29.509ln(x) - 121.26R² = 0.988

0.0

500.0

1000.0

1500.0

2000.0

2500.0

0 1000 2000 3000 4000 5000 6000

U (

W/m

2*°

C)

ṁh (g/min)

11


when varying the shell-side valve opening for the second time.

% Valve

Open


(°C)

U (W/m^2*C)

10% 870 1511 641 18.90 1489.1

30% 874 1542 667 15.44 1831.8

50% 887 1607 721 14.02 2045.9

70% 904 1670 766 13.56 2157.1

After comparing the data in Table 3 and Table 4, it can be seen that the values are extremely

close for each trial. The heat duties for the cold side were a little bit closer in value, only varying

within about ±20 W of each other. The hot side heat duties were about the same as well, but with

a slightly larger variance of ±40 W of each other. It makes sense that the hot side heat duties were

a little more skewed because that is the flow rate that was varied in these trials. On the other hand,

the log mean temperature differences between trials two and three were almost identical. Only a

couple tenths of a degree Celsius separated the two trials which demonstrates the accuracy of the

experiment. Finally, because the heat duties and log mean temperature differences were so similar,

it follows suit that the overall heat transfer coefficients between these trials resembled each other

as well. The variance here was about ±15 W/(m^2*C) except for the when the valve was 70%

open. When the valve was 70% open, the log mean temperature differences were only separated

by 0.03 degrees Celsius and the heat duties by 10 W. This is why the overall heat transfer

coefficients for this run were only 0.5 W/(m^2*C) away from each other. Figure 4 plots the heat

transfer coefficient versus the shell side flow rate for trial three. After examining Figure 4, it was

noticed that the data more strongly resembled a logarithmic relationship in trial three than in trial

two because the R2 value here was 0.9913. By comparison of trials two and three, it can clearly be

seen that the data had a very good accuracy.

12

Figure 5. Overall heat transfer coefficient vs. shell-side flow rate for trial 3.

4.0 Analysis and Discussion of Results

The underlying theory behind the trends that will be discussed can be related back to the

concept of heat transfer. Heat transfer is the exchange of thermal energy between two systems. In

general, energy is transferred from a higher temperature to a colder temperature. There are 3 types

of heat transfers: conduction, convection, and radiation. Each type of transfer occurs with a

different form of medium. Conduction involves the movement from more energetic particles to

less energetic particles. The specific medium of conduction is a solid structure. Convection can be

defined as heat transfer due to the motion of a fluid. The medium used in this form of heat transfer

are fluids. Lastly, radiation is caused by a change in electron configuration, and occurs in a

vacuum. In a given system, an increase in temperature causes the molecules to vibrate, becoming

excited. The molecules then begin to start moving faster and faster. This occurs due to molecular

interactions between each individual molecule. In the case of the heat exchanger, two fluids with

different volumetric flow rates and temperature come into contact. The heat from the hot fluid

excited the molecules in the cold fluid. Therefore, in this experiment, convection is the primary

form of heat transfer.

Heat transfer through convection can be broken down into two types: forced and natural

convection. In the case of forced, there is a “forced” motion, such as a pump, or a fan, that causes

y = 482.21ln(x) - 1939.1R² = 0.9913

0.0

500.0

1000.0

1500.0

2000.0

2500.0

0 1000 2000 3000 4000 5000 6000

U (

W/m

2*°

C)

ṁh (g/min)

13

the movement of fluids. In natural convection, heat transfer and the movement of fluid is caused

by differences in densities. The system in the experiment used pumps to create the flow of water

through the heat exchanger. Since the pumps are forcing the fluids to flow, a heat exchanger

utilizes forced convection to transfer the heat between the two fluids. The following will describe

the different trends that the provided theories support.

Between the trials, various trends can be noted. The primary trend deals with the log mean

temperature difference. In each trial, the log mean temperature difference decreased. In trial one,

it went from 18.98 ºC with a 10% tube-side valve opening to 13.36 ºC with a 100% tube-side valve

opening. Similarly in trial two, the log mean temperature difference decreased from 18.27 ºC with

a 10% shell-side valve opening to 13.52 ºC with a 70% shell-side valve opening. A third trial, that

mimicked trial two found similar results. When trial three was performed it was found that the log

mean temperature difference decreased from 18.90 ºC with a 10% shell-side valve opening to

13.56 ºC with a 70% shell-side valve opening. The reason for this decrease was because as the

volumetric flow rate of the hot and cold sides approached each other, the temperature differential

balanced equally. This trend was able to be observed in all trials because each trial was given

enough time for the heat transfer to reach equilibrium.

A second trend to be noted was with QL. In trial one, the QL remained constant at about

745 W. In trial two, the QL continued to increase from 624 W to 758 W. Likewise, in trial three,

the QL continued to increase from 641 W to 766 W. The major reason for the difference in QL was

due to the surroundings. In trial one, the cold side valve opening was increasing variably from 10%

to 100% as the hot side remained constant at 50% valve opening. As more cold water entered the

system, there was more cold fluid to absorb the constant flow of heat, allowing less heat to escape

to the environment. The reason for the variation of QL in trial two was due to the changing ratio of

cold to hot water in the heat exchanger. The cold side opening in trial two was fixed at 50% while

the hot side opening increased from 10% to 70%. Because of this, the cold side had roughly five

times more water flowing through the system than the hot side initially. This resulted in more heat

being transferred to the cold water and less being lost into the environment. However, as the hot

side valve opening increased, the ratio of cold to hot water decreased. This resulted in more heat

within the system, with a fixed amount of cold water. As a result, more heat escaped into the

environment, resulting in the rise of QL. This heat loss can also be observed in the hot side heat

duty of trials two and three. The hot side heat duty increased from 1452 W to 1660 W for trial two

14

and 1511 W to 1670 W for trial three. The more hot water added to the system, the more heat lost

to the environment.

The final trend that can be noted in the experiment was with the heat transfer coefficient

(U). The heat transfer coefficient is a quantitative characteristic of convective heat transfer

between a fluid medium and the surface the fluid flows over. U represents how well heat is

conducted by a medium. In theory, these U values should be equal to each other because the system

remained the same. According to the equation of the heat transfer coefficient, the heat duty for the

cold side, correction factor, surface area, and log mean temperature difference were the factors

that affected the coefficient. Since correction factor and surface area were constant in this

experiment, the heat duty for the cold side and log mean temperature difference were the only

factors influencing the coefficient. In trial one, there was little variation in the heat duty for the

cold side, meaning the log mean temperature significantly influenced U. However, in trials two

and three, U was affected by both the heat duty and log mean temperature difference, since the

heat duty for the cold side was observed changing. That is why the U observed throughout the

trials were slightly different. For example, U was 1542.7 W/m^2*°C*min when the tube-side valve

was opened 10% in trial one, 1467.4 W/m^2*°C*min when the shell-side valve was opened 10%

in trial two, and 1489.1 W/m^2*°C*min when the shell-side valve was opened 10% in trial three.

In finding that the data in trials one and two were adequate, trial three was performed just

as an extra run to “back up” the existing data. This, “back-up,” correctly showed that the data taken

was precise and accurate throughout the lab.

5.0 Summary and Conclusion

Ultimately, the goal of this experiment was to determine the effects of altering the flow

rates of a small shell and tube heat exchanger. The two technical objectives of the experiment

were to evaluate the effect of variations in flow of the cold, tube-side, and hot, shell-side of a

shell and tube heat exchanger. These changes were observed through the steady-state heat duty

and the overall heat transfer coefficient of the heat exchanger. From the results, it can be

concluded that as the flow rate of a shell and tube heat exchanger is altered, an effect on the heat

duties, log mean temperature difference, and the heat transfer coefficient can be observed. When

the cold side flow rate was incremented, the resulting heat duties for the cold side and hot side

increased proportionately, resulting in a constant Qloss. When the hot side flow rate was

15

incremented, both the heat duties of the cold side and hot side again increased, but the heat duty

of the hot side increased at a faster rate. This resulted in more energy lost. These results were

confirmed when trial three was run. Although, the slight increase of Qloss in trials two and three

did not have a noticeable effect on the log mean temperature difference and the heat transfer

coefficient trends. All three of the trials noticed a decrease of the log mean temperature

difference and an increase of the heat transfer coefficient as the flow rate for the heat exchanger

increased. This means that increasing flow allows for more heat to be transferred between the

two fluids.

These results can be very important when it comes to maximizing the efficiency of a shell

and tube heat exchanger. In order to achieve maximum efficiency, an engineer can take a

desired temperature needed and design the heat exchanger. By taking into account the size and

flow rate, the desired temperature can be reached while maximizing efficiency and reducing

costs. Since altering the flow rate effects the heat transfer as proven by this experiment, flow

rate is a vital part of the design in a shell and tube heat exchanger. Consequently, it is possible to

increase efficiency of a heat exchanger by increasing flow rate while decreasing the temperature

of the heating fluid in a case where a heat exchanger is used to increase the temperature of a

cooler fluid. This means that less energy would be needed to reach the necessary temperature of

the fluid being heated.

Therefore, the results from this experiment lead to information that will help to optimize

the shell and tube heat exchanger. Since heat exchangers are very common in industry,

designing a maximum efficiency heat exchanger at minimal costs will have a vast impact in

furthering the development of the industrial world.

16

6.0 Appendix

6.1 Steady State Data for All Trials

Table 5. Cold side flow variable 10%

Hot in (ºC) Hot out (ºC)

Cold in (ºC)

Cold Out (ºC)

47.66 41.633 20.601 30.65

47.746 41.671 20.599 30.636

47.76 41.717 20.569 30.649

47.623 41.644 20.546 30.639

47.685 41.653 20.585 30.671

47.657 41.627 20.554 30.618

47.599 41.657 20.579 30.659

47.561 41.606 20.552 30.622

47.679 41.565 20.558 30.621

47.691 41.634 20.588 30.637

47.622 41.611 20.55 30.595

47.618 41.549 20.538 30.586

47.71 41.578 20.556 30.601

47.793 41.655 20.553 30.652

47.734 41.747 20.591 30.685

47.64 41.621 20.577 30.624

47.6 41.626 20.571 30.621

47.608 41.603 20.587 30.606

47.647 41.549 20.576 30.589

47.684 41.625 20.572 30.591

47.689 41.631 20.583 30.62

Table 5 shows the steady state temperature data for varying the cold side flow rate at 10% of its

max flow rate. The incoming and exiting temperatures for the hot and cold side fluids are

reported.

17



Cold in (ºC)

Cold Out (ºC)

41.9 35.676 20.635 25.271

41.955 35.711 20.677 25.289

41.922 35.711 20.642 25.267

42.003 35.701 20.637 25.276

42.05 35.721 20.689 25.302

41.827 35.71 20.65 25.297

41.818 35.654 20.64 25.272

42.037 35.636 20.662 25.276

42.043 35.662 20.668 25.281

41.901 35.781 20.667 25.313

41.845 35.683 20.64 25.276

41.761 35.639 20.641 25.274

41.884 35.653 20.658 25.26

41.943 35.719 20.646 25.279

41.87 35.7 20.622 25.28

41.784 35.672 20.652 25.285

41.822 35.611 20.672 25.296

41.861 35.625 20.656 25.284

41.839 35.659 20.662 25.28

41.781 35.604 20.666 25.271

41.858 35.606 20.654 25.266



reported.

18



Cold in (ºC)

Cold Out (ºC)

39.519 33.341 20.713 23.836

39.568 33.349 20.748 23.869

39.591 33.333 20.737 23.855

39.564 33.355 20.697 23.859

39.635 33.408 20.752 23.883

39.701 33.399 20.702 23.886

39.67 33.438 20.728 23.882

39.563 33.423 20.733 23.885

39.416 33.39 20.751 23.88

39.456 33.317 20.717 23.846

39.519 33.323 20.726 23.85

39.506 33.312 20.686 23.829

39.561 33.356 20.717 23.835

39.563 33.318 20.715 23.852

39.566 33.344 20.711 23.863

39.526 33.343 20.683 23.839

39.581 33.351 20.701 23.84

39.613 33.389 20.687 23.867

39.543 33.41 20.727 23.914

39.517 33.336 20.681 23.852

39.545 33.355 20.704 23.852



reported.

19



Cold in (ºC)

Cold Out (ºC)

38.814 32.658 20.692 23.465

38.905 32.662 20.73 23.485

38.892 32.711 20.717 23.477

38.901 32.698 20.681 23.452

39.013 32.697 20.705 23.496

39.092 32.736 20.741 23.509

39.07 32.817 20.697 23.52

38.906 32.767 20.714 23.511

38.706 32.699 20.707 23.482

38.824 32.638 20.734 23.477

38.912 32.667 20.71 23.497

38.935 32.67 20.724 23.472

38.927 32.697 20.713 23.499

38.799 32.677 20.706 23.474

38.795 32.678 20.735 23.483

39.087 32.692 20.743 23.522

39.01 32.756 20.736 23.508

38.949 32.745 20.734 23.509

38.846 32.704 20.702 23.465

38.818 32.708 20.733 23.538

38.807 32.666 20.726 23.516



reported.

20

Table 9. Hot side flow variable 10%


Cold in (ºC)

Cold Out (ºC)

49.151 32.956 20.59 23.606

49.092 32.855 20.53 23.586

49.162 32.903 20.539 23.551

49.243 32.863 20.561 23.605

49.274 32.851 20.526 23.579

49.299 32.939 20.55 23.597

49.301 32.877 20.546 23.592

49.307 32.866 20.546 23.592

49.275 32.898 20.525 23.597

49.291 32.813 20.521 23.601

49.355 32.877 20.525 23.585

49.399 32.877 20.544 23.61

49.404 32.966 20.521 23.597

49.447 32.949 20.541 23.576

49.436 32.902 20.52 23.576

49.476 32.948 20.525 23.561

49.472 33.032 20.499 23.584

49.453 33.027 20.496 23.591

49.5 32.979 20.528 23.583

49.535 32.98 20.518 23.597

49.559 32.985 20.527 23.58

Table 9 shows the steady state temperature data for varying the hot side flow rate at 10% of its


reported.

21



Cold in (ºC)

Cold Out (ºC)

42.774 33.316 20.591 23.863

42.773 33.315 20.589 23.842

42.915 33.297 20.617 23.886

42.872 33.298 20.585 23.855

42.843 33.274 20.581 23.89

42.979 33.285 20.607 23.866

42.982 33.334 20.581 23.879

42.93 33.367 20.597 23.887

42.915 33.383 20.588 23.871

42.948 33.398 20.592 23.887

42.903 33.407 20.597 23.868

42.901 33.333 20.604 23.905

42.852 33.376 20.625 23.889

42.898 33.31 20.59 23.884

42.941 33.326 20.623 23.901

42.876 33.373 20.608 23.883

42.948 33.341 20.619 23.895

42.933 33.365 20.643 23.904

42.864 33.355 20.623 23.879

42.946 33.348 20.61 23.868

42.914 33.368 20.614 23.894



reported.

22



Cold in (ºC)

Cold Out (ºC)

39.855 33.66 20.767 24.069

39.93 33.64 20.812 24.09

39.875 33.663 20.785 24.078

39.881 33.648 20.797 24.078

39.865 33.636 20.764 24.083

39.826 33.677 20.801 24.098

39.791 33.582 20.784 24.077

39.847 33.607 20.786 24.074

39.818 33.637 20.836 24.09

39.91 33.602 20.784 24.087

39.871 33.619 20.789 24.066

39.681 33.632 20.761 24.085

39.744 33.572 20.796 24.08

39.759 33.559 20.784 24.066

39.881 33.579 20.798 24.08

39.877 33.65 20.778 24.082

39.9 33.688 20.802 24.08

39.93 33.685 20.841 24.113

39.812 33.664 20.771 24.067

39.784 33.617 20.781 24.071

39.852 33.672 20.793 24.075



reported.

23



Cold in (ºC)

Cold Out (ºC)

38.258 33.644 20.754 24.065

38.25 33.595 20.766 24.046

38.301 33.616 20.766 24.091

38.32 33.611 20.743 24.065

38.374 33.663 20.759 24.122

38.292 33.667 20.792 24.118

38.252 33.639 20.749 24.085

38.33 33.66 20.799 24.102

38.252 33.656 20.746 24.063

38.189 33.631 20.742 24.076

38.194 33.564 20.745 24.051

38.29 33.609 20.775 24.066

38.322 33.619 20.75 24.075

38.3 33.66 20.795 24.088

38.301 33.642 20.777 24.093

38.252 33.622 20.758 24.074

38.347 33.64 20.774 24.08

38.308 33.665 20.776 24.102

38.306 33.653 20.778 24.087

38.239 33.631 20.763 24.083

38.206 33.647 20.803 24.069



reported.

24



Cold in (ºC)

Cold Out (ºC)

49.151 32.956 20.59 23.606

49.092 32.855 20.53 23.586

49.162 32.903 20.539 23.551

49.243 32.863 20.561 23.605

49.274 32.851 20.526 23.579

49.299 32.939 20.55 23.597

49.301 32.877 20.546 23.592

49.307 32.866 20.546 23.592

49.275 32.898 20.525 23.597

49.291 32.813 20.521 23.601

49.355 32.877 20.525 23.585

49.399 32.877 20.544 23.61

49.404 32.966 20.521 23.597

49.447 32.949 20.541 23.576

49.436 32.902 20.52 23.576

49.476 32.948 20.525 23.561

49.472 33.032 20.499 23.584

49.453 33.027 20.496 23.591

49.5 32.979 20.528 23.583

49.535 32.98 20.518 23.597

49.559 32.985 20.527 23.58



reported. This is the data from a re-run of technical objective 2 and mimics that of Table 8.

25



Cold in (ºC)

Cold Out (ºC)

42.774 33.316 20.591 23.863

42.773 33.315 20.589 23.842

42.915 33.297 20.617 23.886

42.872 33.298 20.585 23.855

42.843 33.274 20.581 23.89

42.979 33.285 20.607 23.866

42.982 33.334 20.581 23.879

42.93 33.367 20.597 23.887

42.915 33.383 20.588 23.871

42.948 33.398 20.592 23.887

42.903 33.407 20.597 23.868

42.901 33.333 20.604 23.905

42.852 33.376 20.625 23.889

42.898 33.31 20.59 23.884

42.941 33.326 20.623 23.901

42.876 33.373 20.608 23.883

42.948 33.341 20.619 23.895

42.933 33.365 20.643 23.904

42.864 33.355 20.623 23.879

42.946 33.348 20.61 23.868

42.914 33.368 20.614 23.894




26



Cold in (ºC)

Cold Out (ºC)

39.855 33.66 20.767 24.069

39.93 33.64 20.812 24.09

39.875 33.663 20.785 24.078

39.881 33.648 20.797 24.078

39.865 33.636 20.764 24.083

39.826 33.677 20.801 24.098

39.791 33.582 20.784 24.077

39.847 33.607 20.786 24.074

39.818 33.637 20.836 24.09

39.91 33.602 20.784 24.087

39.871 33.619 20.789 24.066

39.681 33.632 20.761 24.085

39.744 33.572 20.796 24.08

39.759 33.559 20.784 24.066

39.881 33.579 20.798 24.08

39.877 33.65 20.778 24.082

39.9 33.688 20.802 24.08

39.93 33.685 20.841 24.113

39.812 33.664 20.771 24.067

39.784 33.617 20.781 24.071

39.852 33.672 20.793 24.075



reported. This is a data from a re-run of technical objective 2 and mimics that of Table 10.

27



Cold in (ºC)

Cold Out (ºC)

38.258 33.644 20.754 24.065

38.25 33.595 20.766 24.046

38.301 33.616 20.766 24.091

38.32 33.611 20.743 24.065

38.374 33.663 20.759 24.122

38.292 33.667 20.792 24.118

38.252 33.639 20.749 24.085

38.33 33.66 20.799 24.102

38.252 33.656 20.746 24.063

38.189 33.631 20.742 24.076

38.194 33.564 20.745 24.051

38.29 33.609 20.775 24.066

38.322 33.619 20.75 24.075

38.3 33.66 20.795 24.088

38.301 33.642 20.777 24.093

38.252 33.622 20.758 24.074

38.347 33.64 20.774 24.08

38.308 33.665 20.776 24.102

38.306 33.653 20.778 24.087

38.239 33.631 20.763 24.083

38.206 33.647 20.803 24.069




28

6.2 Sample Calculations

Calculations for Variable Hot Flow Valve at 10% Open:

QCold = (ṁCold)*(CpH2O)*(ΔTAVG) *AVG’s from S.S. Data

= (3892.761905 g/min)*(4.18 J/(g*ºC)*(23.5879ºC-20.5323ºC)

= 49720 J/min

QHot = (ṁHot)*(CpH2O)*(ΔTAVG) *AVG’s from S.S. Data

= (1268.66 g/min)*(4.18 J/(g*ºC)*(32.9211ºC-49.3539ºC)

= 87143 J/min

QLoss = QHot - QCold

= (87143 J/min) – (49720 J/min)

= 37423 J/min

ΔT2 = T Hot, In, AVG. - T Cold, Out, AVG. *AVG’s from S.S. Data

= (49.3538 ºC) – (23.5879 ºC)

= 25.7660 ºC

ΔT1 = T Hot, Out, AVG. - T Cold, In, AVG. *AVG’s from S.S. Data

= (32.9210ºC) – (20.5323 ºC)

= 12.3888 ºC

ΔTlm = (ΔT2 – ΔT1)/ ln (ΔT2/ ΔT1)

= [(25.7660 ºC) – (12.3888 ºC)] / ln (25.7660 ºC) / (12.3888 ºC))

= 18.27 ºC

U = (QCold) / [ΔTlm*A*F]

= (49720 J/min) / [(18.27 ºC)*(0.0322 m2)*(0.96)]

= 88045.7 J/(m2*ºC*min) => 88.05 KJ/(m2*ºC*min)

29

7.0 References

[1]Lytron Total Thermal Solutions. (2016). “What is a heat exchanger?”. Lytron Total Thermal

Solutions.(online article)

http://www.lytron.com/Tools-and-Technical-Reference/Application-Notes/What-is-a-Heat-

Exchanger

[2] Thomasnet.com. (2016). “Types of Heat Exchangers”. Thomas Publishing Company. (online

article)

http://www.thomasnet.com/articles/process-equipment/heat-exchanger-types

[3]Mahans Thermal Products. (2015). “Shell and Tube Heat Exchangers: Pros and Cons.” Mahns

Thermal Products. (online article).

https://heatexchangerswthdougleschan.wordpress.com/2014/12/28/types-of-heat-exchangers-

and-their-pros-and-cons/.

[4] H&C Heat Transfer Solutions. (2015). “Heat Exchanger Types and Selection.” H&C Heat

Transfer Solutions. (online Article). http://www.hcheattransfer.com/selection.html.

http://www.lytron.com/Tools-and-Technical-Reference/Application-Notes/What-is-a-Heat-Exchanger

http://www.lytron.com/Tools-and-Technical-Reference/Application-Notes/What-is-a-Heat-Exchanger

http://www.thomasnet.com/articles/process-equipment/heat-exchanger-types

https://heatexchangerswthdougleschan.wordpress.com/2014/12/28/types-of-heat-exchangers-and-their-pros-and-cons/

https://heatexchangerswthdougleschan.wordpress.com/2014/12/28/types-of-heat-exchangers-and-their-pros-and-cons/

http://www.hcheattransfer.com/selection.html

Documents

Small Shell and Tube Heat Exchanger Final Report ChE 0101 ...ljb59/shellandtube.pdf · Small Shell and Tube Heat Exchanger Final Report ChE 0101 Group A-4 By: Aaron Guche, Caleb Hefright,