Ajman University of Science and TechnologyDepartment of Engineering2014-2015

Graduation Project 1Portable Air Conditioner

Group Members:-Abdulrahman Altenaiji200910971Eisa Ahmed 200911154Ahmed Bitar200911468Mohamed AlObaidli200911449

SupervisorDr. Samir TozinTable of contents:-

Chapter One Introduction .3-4 Objectives 5

Chapter Two System Theory 6-8 System Components 9-11 System Design .12-13

Chapter Three Future work .14 Conclusion .15 References .16

Chapter 1IntroductionThis is the first part of our two semester long graduation project. In this report, we present the research work and design work of the project. The goal of this project is to design and build an eco-friendly portable air conditioning unit. Our advisor gave us a set of design constraints for our design.What is Portable Air Conditioner? Its a Box, which will work as an Air Conditioner with the ability to take it around with you wherever you go and enjoy a clean cold air blowing on your face while enjoying your time out.

Why Portable Air Conditioner?Imagine you are sitting in your house in a hot summer day, and you feel like going out, but what stops you is the hot air outside. Now thats where the Portable Air Conditioner Comes. You will hold that Box lying nears you and go outside, sit where ever you want, and enjoy the Cold air that will be blowing from the box.

How is it done?It will be done using a combination of Software and Hardware. The hardware will be used to make the air cold, and then control everything using the software

What are the advantages of it? Environment Friendly. Nothing harmful comes out of it like normal ACs.

Emirates Society in need of it. Due the hot atmosphere in this region.

Multifunctional. Can be used as a normal Ice Box and as an AC.

Doesnt need much power A rechargeable battery will be used to run it.

Safe.

Easy to use. Useable by all ages.

Objectives

Achieving a temperature close to the normal AC.

Controlling the air flow speed.

Controlling the hardware using software.

Adding LCD screen to show the temperature and the fan speed.

Chargeable by normal socket and car battery.

Using an Arduino to do the software.

Make it improvable in the future.

Making it portable.

Initial Research Work We began the project by looking at the power requirement of a of a typical air conditioner unit.A standard AC uses a compressor to compress.

The CompressorThe compressor used to air condition your car works in a similar way to the one in the refrigerator in your kitchen.The job of the compressor is to move liquid refrigerant around in a pipe.The compressor pumps, or forces the liquid from the evaporator into a condenser and expansion valve, and then back to the evaporator.

We found that even a small compressor would require too much power, so we had to look into a different approach.

How our project worksThe Beginning of the project and first ideaSo since we couldnt use a compressor, we came with an idea of using an ice box, and turning it into an AC by adding ICE and other components that will be described below.So at the begging we had the idea of the box and showing in the figure bellow, we planned to use one radiator, one water pump and one fan for the outtake.The water pump will be connected to the radiator, and there will be a fan on top of it, that will be blow the air out.And for the intake we would use a copper pipe to pass the air through, from the intake to the radiator, and this copper pipe will be inside the box which will be full of ice, and some water for the water pump.But unfortunately, by applying this design we werent able to achieve our aim of getting a low temperature and it wasnt satisfying.So we made modifications to our project which changed it completely.Our Project by the end:-So after trying the first idea and testing it and not getting the results we wanted, we came with these modifications (Shown in pics below)

We had to use 2 radiators instead of 1 radiator only, and instead of 1 fan for the outtake, we would have 1 fan for the intake and 2 fans for the outtake.And what we did at the beginning was by dividing the box into 2 champers, and on one side we have the intake fan, and it will blow the air inside the box, this air will go through the ice, and the then through the radiator which we placed in between the 2 champers, And then the air will move into to the 2nd champers and go through the ice again and into a second radiator, and on top of this radiator we have 2 fans which will be used for the outtake. We used 2 fans instead of 1 fan because our project idea was to make it useable by 2 users in a golf cart.

Results

Plot:-

Project Features

The basics features for this design were:

1- Must be portable; weight must not exceed 15Kg.

2- The size should be no bigger than 60cm x 40cm x 40cm.

3- The unit should be powered by a 12V rechargeable battery, no more than 5000m Ah. 4- The unit should be able to operate for 3 hours continuously on one charge.

5- The unit must display the temperature of the output air, and the ambient air.

Specifications

So after testing the project and getting the results we put up these specifications,, 1-The outcome temperature is 20 *C lower than the surrounding temperature.2-We can put up to 6.5kg of ice.3-It weight 4.9kg empty and 11-12kg full with ice.4-The Ice takes around 1hour and 30min to melt.5-It need 3.5Liters of water divided between the two champers.5-The ice can last for 1day when idle.6-We can get cold air for 2 hours when running continuously.7-The measurements of the box are 45cm long, 27cm wide, 32cm Height.8-The battery last up to 2 hours and half when running continuously.

Chapter 2The System

System Theory Heat ExchangeWhat is a heat exchanger?Suppose you have a gas central heating furnace (boiler) that heats hot-water radiators in various rooms in your home. It works by burning natural gas, making a line or grid of hot gas jets that fire upward over water flowing through a network of pipes. As the water pumps through the pipes, it absorbs the heat energy and heats up. This arrangement is what we mean by a heat exchanger: the gas jets cool down and the water heats up.A heat exchanger is a device that allows heat from a fluid (a liquid or a gas) to pass to a second fluid (another liquid or gas) without the two fluids having to mix together or come into direct contact. If that's not completely clear, consider this. In theory, we could get the heat from the gas jets just by throwing cold water onto them, but then the flames would go out! The essential principle of a heat exchanger is that it transfers the heat without transferring the fluid that carries the heat.

Photo: How a simple heat exchanger works. A hot fluid (shown in red) flows through a tube coiled inside a larger shell through which another, colder fluid (shown in blue) is running in the opposite direction. Heat is exchanged by the fluids: the hot fluid cools down and the cold fluid warms up, without them actually coming into contact and mixing.

What are heat exchangers used for?

You can see heat exchangers in all kinds of places, usually working to heat or cool buildings or helping engines and machines to work more efficiently. Refrigerators and air conditioners, for example, use heat exchangers in the opposite way from central heating systems: they remove heat from a compartment or room where it's not wanted and pump it away in a fluid to some other place where it can be dumped out of the way.In power plants or engines, exhaust gases often contain heat that's heading uselessly away into the open air. That's a waste of energy and something a heat exchanger can certainly reduce (though not eliminate entirelysome heat is always going to be lost). The way to solve this problem is with heat exchangers positioned inside the exhaust tail pipes or smokestacks. As the hot exhaust gases drift upward, they brush past copper fins with water flowing through them. The water carries the heat away, back into the plant. There, it might be recycled directly; maybe warming the cold gases that feed into the engine or furnace, saving the energy that would otherwise be needed to heat them up. Or it could be put to some other good use, for example, heating an office near the smokestack.

System Components RadiatorA radiator is a type of heat exchanger. It is designed to transfer heat from the hot coolant that flows through it to the air blown through it by the fan.Most modern cars use aluminum radiators. These radiators are made by brazing thin aluminum fins to flattened aluminum tubes. The coolant flows from the inlet to the outlet through many tubes mounted in a parallel arrangement. The fins conduct the heat from the tubes and transfer it to the air flowing through the radiator.The tubes sometimes have a type of fin inserted into them called a tabulator, which increases the turbulence of the fluid flowing through the tubes. If the fluid flowed very smoothly through the tubes, only the fluid actually touching the tubes would be cooled directly. The amount of heat transferred to the tubes from the fluid running through them depends on the difference in temperature between the tube and the fluid touching it. So if the fluid that is in contact with the tube cools down quickly, less heat will be transferred. By creating turbulence inside the tube, all of the fluid mixes together, keeping the temperature of the fluid touching the tubes up so that more heat can be extracted, and all of the fluid inside the tube is used effectively.

TransistorA transistor is a miniature electronic component that can do two different jobs. It can work either as an amplifier or a switch. And in our project we used the transistor as a switch.When used as switch. A tiny electric current flowing through one part of a transistor can make a much bigger current flow through another part of it. In other words, the small current switches on the larger one. This is essentially how all computer chips work. For example, a memory chip contains hundreds of millions or even billions of transistors, each of which can be switched on or off individually. Since each transistor can be in two distinct states, it can store two different numbers, zero and one. With billions of transistors, a chip can store billions of zeros and ones, and almost as many ordinary numbers and letters Arduino

Arduino is an open-source electronics platform based on easy-to-use hardware and software. It's intended for anyone making interactive projects.

ARDUINO BOARDArduino senses the environment by receiving inputs from many sensors, and affects its surroundings by controlling lights, motors, and other actuators. ARDUINO SOFTWAREYou can tell your Arduino what to do by writing code in the Arduino programming language and using the Arduino development environment.

Temperature sensor LM35The LM35 series are precision integrated-circuit temperature sensors, whose output voltage is linearly proportional to the Celsius (Centigrade) temperature.

The LM35 thus has an advantage over linear temperature sensors calibrated in Kelvin, as the user is not required to subtract a large Constant voltage from its output to obtain convenient Centigrade scaling. The LM35 does not require any external calibration or trimming to provide typical accuracies of 0.25C at room temperature and 0.75C over a full 55 to +150 C temperature range

3Fans Wires switches Water pumps Bread Bored Pipe Ice Box Diode Resistors

System Design System Sketch (first sketch)

System Sketch (Last skecth)

System Flow Chart (first)The system will start with the fan at speed 1,We will have 3 push buttons to control 3 speeds, 1,2,3And we will have an LCD screen to display the fan speed and also The Temperature reading that it will get from the heat sensor.

System Flow Chart (Last)

Code

Chapter 3Future Work

Adding Solar Panel By Adding Solar Panel we can charge the battery at any time, and therefor; get rid of the need of charging the battery before going out, and it will make the AC run as long as there is sun.

Making a Wireless Controller By using wireless controller it will easier to turn OFF or ON the AC, while being a bit far.

Make it a smart machine Make it smart by being able to recognize a sort of voice command. Make it able to turn ON or OFF or change the fan speed depending on the temperature in the camp. Adding motion sensors or pressure sensors so the fans would turn On or OFF automatically.

Conclusion

We got to our object of achieving a low temperature. We were able to display the temperature on the LCD screen. We were able to maintain the temperature for a good period of time. The hardware was controlled by the software like what was explained in the previous point. We used an Arduino to do the software.

References

http://www.arduino.com http://motorshielddatasheet.com http://www.explainthatstuff.com/howtransistorswork.htmlhttp://www2.ece.ohio-state.edu/~passino/LM35.pdfhttp://www/fritizing.com31