Air Conditioning Measurement Device

1. YEDITEPE UNIVERSITY, ISTANBUL
Air Conditioning Measurement Device
ME 403 Instrumentation and Experiment Design
Term Project Report
Fall 2014
Group 3B
Berk KÖTEŞLİ
Göksenin ÖZKAN
Salih GÜVEN
Department: Mechanical Engineering
ME 403
Instructor: Asst. Prof. A. Bahadır OLCAY
Asst. Prof. Nezih TOPALOĞLU
Asst. Prof. Koray K. ŞAFAK
02.01.2015

2. II
Letter of Authorization
ME 403 Term Project Report
APPROVED BY:
Asst. Prof. A. Bahadır OLCAY :…………………………………………
Asst. Prof. Nezih TOPALOĞLU :………………………………………..
Asst. Prof. Koray K. ŞAFAK : ……………………………………...……
STUDENT NAME:
Berk KÖTEŞLİ: ...........................................................................................
Göksenin ÖZKAN: ………………………………………………………..
Salih GÜVEN: ............................................................................................
DEPARTMENT:
Mechanical Engineering
DATE OF APPROVAL: 02.01.2015

3. III
Table of Contents
1. Objectives ………………………………………….……………………………..…….…1
2. Introduction......................……………………………………………………….………...2
3. Mechanical Design……………………………………………………...……………...…3
4. Procedure …………………………………………………...………………………...….7
5. Instruments and Wiring ………..……………………………...……..……………..……8
6. Calibration ………..…………………...…………………………..…………………....18
7. Codes of the System…………………………………………………………………...…20
8. Uncertainty Analysis….…………………………………………………………...……..24
9. Conclusion………………………………………………………………………………....27
10. References ………………………………………………………………………………28

4. 1
1. Objectives
Air conditioning systems are one of the most crucial, indispensable and commonly
used systems in large buildings and structures such as shopping malls, business centers,
hospitals etc. Therefore, delivering the right amount of air at desired temperature and flow
rate and efficiency of the air conditioning system plays very important role to provide
comfortable and required environment conditions to people who make various activities in the
buildings. For that reasons, several sensor are used in the system to check the air conditions in
each part of the system and control the air conditioning system to provide desired air when
heating and cooling coils of the system works properly. Aim of this project, a compact device
will be designed and built to check and measure the temperature, pressure, velocity and mass
flow rate of the air across the heating coil and cooling coil of an air handling unit. Also,
instantaneous data of the temperature, pressure, velocity and mass flow rate will be read and
after the analyzing process, each data which come from the sensors will be transferred to the
Arduino microcontroller which is located into the device and average, maximum and
minimum values of the data will be calculated and shown. Thus, according to data of the
measurements, air handling unit can be controlled or calibrated. Also, uncertainty analysis
will be completed to observe the reliability interval of the measurements.

5. 2
2. Introduction
For the selecting right equipment and sensor to measure the system conditions
correctly and in a portable way according to adequate and expected accuracy interval, a
comprehensive research have been completed to select sensors and part of the devices. Three
useful and easily purchasable sensors and equipment have been purchased to build our device.
Firstly, to measure the temperature, pressure, velocity and mass flow rate, commonly used
and cheap equipment was purchased by considering accuracy interval. However, because of
measuring the mass flow rate by using sensor or device in our air conditioning system would
be too expensive or inefficient, mass flow rate will be calculated theoretically by using
velocity of the air and geometry of the system. Also Arduino microcontroller was purchased
to control all sensors which are connected to Arduino and data will be processed and
calculations will be completed by using Arduino microcontroller. Data will be shown on the
monitor which is located on the device. All details about the sensor and parts of the devices
are shown in the next part of the report

6. 3
3. MechanicalDesign
In this part of the report mechanical design criteria of the device is explained. Firstly,
when the project details were announced, design criteria of the device were started to create.
Measurement device should have been portable, compact, economical and device should have
been controlled easily and used in various working areas. Also, it should have been built by
using factory made products. It means that, all components must be purchasable and
economical. There must be no handmade component in device because of the fact that,
repairing and replacement of the parts of the device must be done easily. First 3D design of
the device which is also shown in survey report is shown below.
Figure 3.1: First 3D model of device
First 3D model was drawn in Solidworks software and it can be produced as
handmade. However, according to design motto, there must be no handmade component in
the device. So, a new design of the device was created by using purchasable equipment. Final
Mechanical design of the device is shown in figures.

7. 4
Figure 3.2: 3D model of the device (Solidworks)
Figure 3.3: Front view
Figure 3.4: Top view
Figure 3.5: Left view

8. 5
Figure 3.6: Final design of device (real)
Figure 3.7: Top view of the device

9. 6
Figure 3.8: Front view of the device
In final design of the measurement device, all criteria and mottos were reached. Device
was built and became ready to measurement as compact, portable, efficient, economical, able
to work all sensors together in various working areas. It can be work by using 9V battery or
USB cable with energy supplier.

10. 7
4. Procedure
In this part of the report, procedure is shown below as step by step.
 After informing about project details and objectives, sensors and equipment were
investigated widely.
 According to objectives, temperature, pressure and air velocity measurements would
be accomplished. Then, air flow rate of the system would be determined by using air
velocity measurements and geometry of the air handling unit.
 Most efficient, compatible and economical sensors, microprocessor and screen which
were the fundamental instruments of the device were selected by considering accuracy
interval that is suitable for our requirement of the device.
 According to our criteria and mottos, for building a compact device, all sensors
worked together in only one run.
 Codes of each sensor were written in Ardunio Software.
 Device became ready to measure temperature, pressure and air velocity.
 After that part sensors were calibrated by using different methods. For LM35
temperature sensors calibration, ice-water mixture was used. For BMP180 pressure
sensor which has already been calibrated, sensor was checked at the sea level. For
TCRT5000 sensor which was used for measuring air velocity and air flow rate, wind
tunnel at the laboratory was used.
 After the calibration, device was tested and confirmed the measurements results.
 According to design criteria, device should have been compact. Therefore, all
instruments have been gathered in box.
 Device was built as working with 9V battery or USB cable. Also all measurements can
be controlled and started using on-off button. Then measurements can be checked on
screen.
 For velocity measurements, a wooden stick was built whose size is compatible with air
handling unit.TCRT5000 and weathervane fixed on it. Also measurements can be
done each part of the unit by changing the position of the weathervane and sensor.
 Finally, device and all other instruments were connected and device was set into
operation as a whole and measurements were started. After the final testing, device
ready to measuring successfully.
 For each sensor and conditions, uncertainty calculations were completed.

11. 8
5. Instruments and Wiring
At the beginning of this project, detailed market search, internet search was done and
this search was indicated in the survey report. After this search, three different options were
determined for each sensor type, board type and these options were compared in the survey
report. The most important parameters to choose sensors are economy and accuracy. After
that, coherence between sensors and microcontroller board was also checked. Ultimately, the
most suitable ones were chosen. All instruments were shown below.
Experimental Setup and Equipment;
 LM35 : Temperature Sensor
 BMP180 : Pressure Sensor
 TCRT5000: Proximity Sensor, Weathervane
 Arduino Uno: Single-board microcontroller
 Jumper Wires
 Bread board
 16 x 4 LCD Screen
 9 V Battery
 15 Watt Standard Adapter Box

12. 9
5.1 LM35
LM35 (Figure 5.1) was used as the temperature
sensor of our project. Although LM35 is the most
economical sensor, this sensor provides all desired features
including working perfectly with Arduino Uno.
Additionally, there are several accessible sources on the
measurement is determining the temperature difference
between heat resistors in the air handling unit. One of the
temperature sensors was placed in front of the heat
resistors and other one was placed at the internet about
LM35. These sources help very much especially at
connection part.
Figure 5.1: LM35 Temp. Sensor
The main features of LM35 related with our project are like that;
 Able to work in −55˚ to +150˚C range
 Able to operate in 4 – 30 V interval ( Suitable for Arduino Uno)
 0.5˚C accuracy
 Low-self heating (Due to low-self heating there is no concern about at working
high temperatures.)
 Economical (3 TL)
Two LM35 temperature sensors were used for this project since the aim of the
measurement is determining the temperature difference between heat resistors in the air
handling unit. One of the temperature sensors was placed in front of the heat resistors and
other one was placed at the back of these heat resistors. Thus, measuring two different
temperatures from two different parts of the air-handling unit were completed.

13. 10
5.2 BMP 180
The market of the cheap pressure sensors is very narrow in Turkey. Despite this
narrowness, BMP series barometric pressure sensors satisfy us and all sensors of BMP series
provide all desired features. Therefore, the main parameter among the BMP series pressure
sensors is the cost. Because of this, BMP 180(Figure 5.2) was selected as the pressure sensor.
It is 10 TL that is significantly cheaper than the other pressure sensors such as BMP 085.
.
Figure 5.2 : BMP 180 Pressure Sensor
The major feature that provides all requirements is like that;
 Able to work in wide pressure range 300 - 1100hPa (1 hPa = 100 Pa)
 Able to operate in 1.8 – 3.6 V interval (Suitable for Arduino Uno)
 Factory-calibrated
 Including a temperature sensor
The first goal of the project is measuring the pressure in the air- handling unit,
although instant pressure difference was tried to measure as the second - goal, when the
deadline was come closer. Because of the late informing about second-goal, this goal was
cancelled by the instructor. In addition, our group was able to accomplish this goal, but a
switch that is not economical for connecting to the Arduino Uno must be bought and the
remaining time to deadline was not enough for doing demo about that.

14. 11
Figure 5.3 : Red circle shows the location of the BMP 180 in the air-handling unit
As shown in Figure 5.3 , BMP 180 was placed after the heating resistors and
before the fan.
5.3 TCRT5000 and Weathervane
Actually, TCRT5000 (Figure 5.4) is a proximity sensor
that measures distance. In this project, this proximity sensor
was used with different working principle. The eyesight of this
sensor is between 0.2 mm and 1.5 mm. According to this
information, new working principle for TCRT5000 was formed
like that if the propeller of the weathervane (Figure 5.5) is in
TCRT5000’s eyesight, it must be counted, so RPM of the
weathervane can be found .In other words, TCRT5000 was
sticked at the back of the weathervane (Figure 5.6) and it
counts all passes of the propellers to measure the RPM of the
weathervane. Figure 5.4 : TCRT 5000

15. 12
Figure 5.5 : Weathervane Figure 5.6 : TCRT5000 and Weathervane
RPM can be converted to velocity and mass flow rate of air can be found.Converting
RPM to velocity is done with a equation that was found in the calibration part.This part was
explained detailly in the calibration part of this report.
The price of TCRT5000 is 7 TL and the price of the weathervane is just 2 TL. This is
the one of the cheapest measurement type.
TCRT5000 and weathervane combination was located in front of the fan in the air-
handling unit.(Figure 5.7)
Figure 5.7 : Weathervane was placed in front of the fan/compressor.

16. 13
5.4 Arduino Uno
Arduino Uno (Figure 5.8) was selected as the microcontroller – board for this project.
It is an economical solution (35 TL) and compatible with all sensors that were chosen. Also,
Arduino Uno is the most common microcontroller board and mini/portable device that was
wanted.
Figure 5.8: Arduino Uno
The significant properties of Arduino Uno were shown in Table 1.
Table 1
Arduino Uno was connected to computer via USB connection.Therefore, Arduino Uno
was controlled from computer via Arduino Software and codes were uploaded to
board.Arduino Software is an application that provides writing a code and uploading it to the
board.Wiring diagram of sensors and Arduino Uno was shown in experimental setup part of
this report.Also, codes were indicated in codes part of this report.
Microcontroller ATmega328
InputVoltage (recommended) 7 - 12 V
InputVoltage (limit) 6 - 20 V
OperatingVoltage 5 V
DigitanI/OPins 14
AnalogInputPins 6
DC Currentper I/OPin 40 mA
DC Currentfor 3.3V Pin 50 mA
FlashMemory 32 KB
ClockSpeed 16 MHz

17. 14
5.5 Jumper Wires
Jumper wires (Figure 5.9) were used to make connection between sensors and the
microcontroller board.These wires are easy-to-connect type cables.
Figure 5.9: Jumper Wires
5.6 Bread Board
Bread boards (Figure 5.10) that are used to make electronic prototypes are quite
expensive plastic rectangular tool.Working principle of bread board is that the vertical
columns on the bread board are connected to the same conductor , so electricity circuit can be
prepared easily with increased hole numbers.
Figure 5.10 : Bread Board
5.7 LCD Screen
16 x 4 Lcd screen (Figure 5.11) was used to show the measurements.
Figure 5.11 : LCD
Screen

18. 15
Figure 5.12 : Device with Connected Sensors
At the end of this project, air conditioning measurement device was set on to air-
handling unit in thermodynamics lab.Temperature difference, pressure , velocity , mass flow
in the air-handling unit can be measured at the same time via our device as shown in
Figure 5.13.
Figure 5.13 : Air Conditioning Measurement Device on the Air-Handling Unit

19. 16
5.8 Adapter Box
This equipment was used as outer case of the device.Except for sensors, all other
instruments are placed into this box which is shown below.
Figure 5.14 : Adapter box – Outer case of the device

20. 17
Wiring:
In this part, wiring of the device is shown below.All connectoions between sensors,
LCD, battery, Arduino and breadboard are monitored in Figure 5.15. Device can be used by
using 9V battery or USB cable. It means that, in terms of portability, device can be used 9V
battery, but in terms of efficiency and economical reasons, device can be used by using USB
connection.
Figure 5.15 : Wiring diagram of the measurement device
Figure 5.15 : Wiring schema of the device
LM35 (1) LM35 (2) BMP180 TCRT5000
SDA SCL GND VIN D0 VCC GND
5V A0 GND 5V A1 GND A4 A5 GND 3.3V 2 3 4
Figure 5.16 : Wiring orientation of sensor extension socket

21. 18
6. Calibration
6.1 LM35 Calibration
The safest calibration method for LM35 is done with ice-water mixture.If it is done
with kettle some safety problems may be occured.Therefore, this way was chosen.
LM35 was dropped in the cup that was filled with ice-water mixture.When the balance
between water and ice was observed, LM35 was indicated as 0 ˚C which is the melting point
of ice.Although LM35 was come fully-calibrated , calibration was checked with this
way.(Figure 6.1)
Figure 6.1 : LM35 Calibration
6.2 BMP 180 Calibration
BMP 180 was come fully-calibrated, it gives reliable results.In spite of coming fully-
calibrated,calibration of BMP 180 was checked at the sea level.It indicated 101326 Pa at the
sea level at the Uskudar Coast.
6.3 TCRT5000 Calibration
TCRT5000 is used to calculate/measure RPM of the weathervane, but the requirement
of this project is not calculating RPM.That’s why,weathervane with TCRT5000 needs a
calibration to find each velocity value for each RPM. After this, mass flow can be calculated
easily.

22. 19
Figure 6.2: Weathervane in the Wind Tunnel
TCRT5000 was calibrated in the wind tunnel (Figure 6.2). Instant Hz. value in the
wind tunnel was measured by pitot tube in the wind tunnel and sent to excel on the
computer.These Hz. values was converted to velocity on excel.At the same time RPM of
weathervane was measuring.This procedure was done for various Hz. Values.At the end of
the calibration, RPM values and velocity values were gathered in one excel document and
Graph 1 was plotted as Velocity vs. RPM . Third order equation that was shown in Graph 1
was occured after third order polynomial trendline was plotted.Founded equation was put in
our code. Instant RPM values are put in this equation, so velocity can be calculated through
this equation. Mass flow can be found with this procedure.Q = V.A equation where “A = 0.29
m x 0.29 m” is used to calculate mass flow. Some Velocity-RPM values was shown in Table
2.
Graph 1:Velocity vs. RPM
y = -2E-10x3 + 2E-06x2 - 0,0005x
R² = 0,9788
-1
0
1
2
3
4
5
6
7
8
0 500 1000 1500 2000 2500 3000
Velocity(m/s)
RPM
Velocity vs. RPM RPM velocity(m/s)
0 0
962,17 0,67
1238,90 1,12
1291,53 1,60
1435,09 2,08
1584,67 2,61
1766,30 3,09
1871,59 3,62
2075,90 4,12
2305,38 4,60
2496,19 5,16
2639,45 5,67
2733,49 6,25
2731,27 6,76
2701,28 7,18
Table 2

23. 20
7. Codes ofthe System
In this part of the report, codes which were used in Arduino Microprocessor for
measurements are shown below.

24. 21

25. 22

26. 23

27. 24
8. Uncertainty Analysis
In this part uncertainty analysis was done for Reynolds number because the velocity
sensor is hand made. Reynolds Number contains three different parameters. These parameters
are velocity, diameter and kinematic viscosity.
First of all, velocity sensor is hand made so there is not any data about uncertainty of
this sensor. Thus, 80 data were taken in air handling unit at 10 Hz fan speed for calculating
uncertainty for velocity.
Secondly, the uncertainty of diameter must be calculated. Our air handling unit has
square profile thereby according to knowledge of Fluid Mechanics; the Hydraulic Diameter
calculation is needed. After the Hydraulic Diameter calculation, the uncertainty analysis for
diameter is finished.
Lastly, Kinematic Viscosity was found from dry air properties table for 20oC. The
uncertainty about Kinematic Viscosity is coming from temperature measurement. However,
when the values of Kinematic Viscosity checked for 19.5o C and 20.5oC there was no
necessary change (9x10-8). Thus, the Kinematic Viscosity value at 20oC can be used directly
at calculations.
 Velocity Uncertainty :
Figure 8.1 : The Velocity vs # of Data

28. 25
 Diameter Uncertainty :
𝐴𝑟𝑒𝑎 = 𝑎 ∗ 𝑏 = 0.29𝑚 ∗ 0.29𝑚 (𝑎 = 𝑏 = 0.29𝑚 ± 0.0005𝑚)
𝐻𝑦𝑑𝑟𝑎𝑢𝑙𝑖𝑐 𝐷𝑖𝑎𝑚𝑒𝑡𝑒𝑟 ∶ 𝑑 =
4𝑎𝑏
2(𝑎 + 𝑏)
, 𝑑 = 0.29 𝑚
d =
4(𝑎𝑏)
2(𝑎+𝑏)
𝜕𝑑
𝜕𝑎
=
2𝑏2
(𝑎+𝑏)2 =
1
2
𝜕𝑑
𝜕𝑏
=
2𝑎2
(𝑎+𝑏)2 =
1
2
𝑊𝑑 = √(
𝜕𝑑
𝜕𝑎
𝑤 𝑎)2 + (
𝜕𝑑
𝜕𝑏
𝑤 𝑏)2 = 0.000035355m
 Kinematic Viscosity :
𝛾 = 1.505𝑥10−5
𝑚2
𝑠
Table 2 : Sample data for Velocity Uncertainity

29. 26
Reynolds Number:
 𝑉 = 2.75 ± 0.24 𝑚/𝑠
 𝐷 = 0.29 ± 3.5355𝑥10−5
𝑚
 𝛾 = 1.505𝑥10−5 𝑚2
𝑠
𝑅𝑒 =
𝑉𝐷
𝛾
𝜕𝑅𝑒
𝜕𝑉
=
𝐷
𝛾
=
0.29
1.505𝑥10−5
= 19269.10299
𝜕𝑅𝑒
𝜕𝐷
=
𝑉
𝛾
=
2.75
1.505𝑥10−5
= 182724.2525
𝑊𝑅𝑒 = √(
𝜕𝑅𝑒
𝜕𝑉
𝑤 𝑉)2 + (
𝜕𝑅𝑒
𝜕𝐷
𝑤 𝐷)2 = 4635.433
𝑅𝑒 = 52990 ± 4635.433 (±8.7%)

30. 27
9. Conclusion
The major aim of this project is making a device that can measure temperature
difference, pressure, velocity and mass flow in the air-handling unit. Fortunately, all of these
aims were achieved. Firstly, temperature difference between the heating resistors in the air-
handling unit can be measured with two LM35 temperature sensors which were located in
front of and at the back of the heat resistors.
Secondly, pressure can be measured easily through BMP 180 and if it is needed BMP
180 can be placed another place, so pressure difference can be observed like that. As it is said
in Instruments/BMP 180 part, two BMP 180 sensors could not be used due to late informing
about pressure difference goal. Additionally, Arduino Uno needs a switch that is not suitable
to run two BMP 180. Despite these drawbacks; our group was able to run two BMP 180 at the
same time if our group had more time to deadline. At least, pressure difference can be
observed with one BMP 180, because our device is very compact and mobile, so it can carry
easily.
Next, mass flow and velocity in the air-handling unit can be seen with the RPM of the
calibrated weathervane. TCRT5000 and Weathervane combination was located in front of the
compressor/fan to measure RPM of the air in the air-handling unit. These RPM values that are
taken from TCRT5000 are used to find velocity and mass flow. Thus, RPM is converted to
velocity and mass flow with the help of the velocity vs RPM graph which was plotted after
calibration. Calibration is the most important part of this measurement type since this
measurement type was created from scratch. Calibration was really needed to find each
velocity, mass flow value for each measured RPM. Only counting RPM specifies nothing.
After calibration, RPM values are meaningful now.
Finally, uncertainity analysis was done for system. In this system, uncertainity of all
sensors were known. However, velocity measurement sensor was handmade thereby there is
not any meaningful knowledge about uncertainity. For this reason, uncertainity analysis was
done for Reynolds Number that contains velocity, diameter and kinematic viscosity. Here, the
key point is velocity. The fluctuation of the velocity was found to determine the uncertainity
of the velocity measurement. Then, uncertainity for diameter was found. In addition, there
was no need to include uncertainity of kinematic viscosity because a 1oC difference in
temperature made 9x10-8 change in viscosity there by it was really unnecessary for
calculations. With all these knowledge uncertainity analysis was done successfully.
Actually, all of these goals were achieved in this project. Additionally, device was
designed carefully and it is compact, easy-to-use; it has just one button and one screen on it,
portable; it can be carried everywhere and sensors are removable. Also, our device can run all
sensors at the same time, so all measurements can be taken simultaneously.

31. 28
10. References
[1] Arduino http://www.arduino.cc/
[2] Fritzing Software http://fritzing.org/home/
[3] LM35 Data Sheet
http://pdf.datasheetcatalog.com/datasheet/nationalsemiconductor/DS005516.PDF
[4] TCRT 5000 Data Sheet http://www.vishay.com/docs/83760/tcrt5000.pdf
[5] BMP180 Data Sheet https://ae-
bst.resource.bosch.com/media/products/dokumente/bmp180/BST-BMP180-DS000-09.pdf