-
Fabrication Of Domestic Deep Freezer
CHAPTER THREE -- [Total Page(s) 3]
Page 3 of 3
-
-
-
3.3.3 THE EVAPORATOR.
This is the part of the refrigeration system that is doing the actual cooling, (i.e. cooling occurs during this stage). Because its function is to absorb heat into the area to be cooled. The refrigerant is let into and measured by a flow control device, and eventually released to the compressor. The evaporator consists of finned tube, which absorbs heat from the air blown through a coil by fans. Fins and tube are made of metal with high thermal conductivity to maximize heat transfer. The refrigerant vaporizes from the heat it absorbs into the evaporator. Also evaporators are of different sizes depending on the required condition of temperature in the system. The size use for this project is 5/16 " 0.D χ 50 because it is the most suitable for a much lower temperature.
3.3.4 CAPILLARY TUBE
This device operate on the principle that a given weight of refrigerant liquid will pass through a capillary more readily than the same weight of gas will do at the same pressure. Immediately the condensed refrigerant enters the capillary tube, the mass flow of this refrigerant will be reduced them by giving more room for cooling time.
ADVANTAGE OF THE TYPES OF CAPILLARY TUBE USED FOR THIS PROJECT LIES IN:
Its simplicity.
Ease of being welded to the suction for heat exchanging purpose.
3.3.5 DRIER.
The drier is used to absorb moisture content form refrigerant. It contains desiccant made up of silica gel a material that has ability to absorb any acid already formed and has greate4r affinity for moisture. These desiccants are made such that they do not react with the refrigerant oil or the refrigerant itself.
This drier is a very important component of the system because it helps in removing foreign material and dirt from the refrigerant so that they will not be able to cause damage to the compressor values and the controlling devices in a refrigerating system. The presence of a very fine filter in it enables it to perform this purpose.
3.3.6 LAGGING MATERIAL.
The function of lagging material in the system is to prevent heat loss by conduction and radiation. The most commonly used lagging material is polystyrene and fiberglass. The one employed for this project is the polystyrene because it is more effective and readily available. It also gives the system stability and strength against any load.
3.3.7 THE THERMOSTAT
The thermostat is used for controlling the compressor, i.e, for stating and stopping it as energy demand charges.
3.3.8 COOLING FAN
Function of the fan is to serve as the cooling medium for the compressor to avoid over heating which could have otherwise caused damage to the motor winding and the mechanical devices in the compressor.
3.3.9 SHEET METAL.
The sheet metal used is made up of mild steel of 0.7mm thickness. The thickness selected is optimum for the system otherwise it will lack strength and stability.
3.3.10 REFRIGERANT.
A refrigerant is a substance or mixture, usually a fluid used in heat pump and refrigeration cycle. In most cycle it undergoes phase transition from a liquid to a gas and back again. Fluoro carbons, especially chloro fluro carbon, became common place in the 20th century, but they are being phased out because of their ozone depletion effects. Other common refrigerants used in various applications are ammonia, sulphurdioxide, and non-halogenated hydrocarbon such as propane.
The ideal refrigerant would have favorable thermodynamic component and be safe, including free from toxicity and flammability. It would not cause ozone depletion or climate change. Since different fluids have the desired traits in different degree, choice is a matter of trade –off.
The desired thermodynamic properties are a boiling point, some what below the target temperature a high heat of vaporization, a moderate density in liquid form, a relatively high density are affected by pressure, refrigerants may be made more suitable for a particular application by choice of operating pressures.
The refrigerant used for this project is R600a because of some properties such as:
Non-toxicity.
Non- inflammability.
Low cost.
Availability.
CHAPTER THREE -- [Total Page(s) 3]
Page 3 of 3
-
-
ABSRACT - [ Total Page(s): 1 ]ABSTRACTRefrigeration is term used to denote the maintenance of a body at a temperature lower than that of its surroundings. The applications of refrigeration are many and varied. In addition to the common applications of refrigerationin the manufacture of ice, in the preservation of foods, in air-conditioning filed, and in the creation of skating rinks, the refrigeration effect is also used in the presentation of blood plasma, in the low-temperature treatment of metals and in the liquefaction o ... Continue reading---
APPENDIX A - [ Total Page(s): 1 ] ... Continue reading---
LIST OF TABLES - [ Total Page(s): 1 ]LIST OF TABLE4.1 Material Selection, Fabrication Details and Assembly 4.3 Bill of Engineering Materials and Evaluation 4.4 Trouble Shooting and Service Chart ... Continue reading---
LIST OF FIGURES - [ Total Page(s): 1 ]LIST OF FIGURERefrigeration Cycle Isometric View of Fabrication of Domestic Deep Freezer Orthographic Projection of Fabrication of Domestic Deep Freezer Explode View of Fabrication of Domestic Deep Freezer ... Continue reading---
TABLE OF CONTENTS - [ Total Page(s): 1 ]TABLE OF CONTENTTitle page Approval page Dedication Acknowledgement Abstract Table of Content List of Tables List of Figure CHAPTER ONE: Introduction1.1 History of Refrigeration 1.2 Important of Refrigeration Application 1.3 Freezer 1.4 Impact of Life Cycle 1.5 Aims and Objectives CHAPTER TWO: LITERATURE REVIEW2.1 Absorption System of Refrigeration 2.2 Mechanism of Absorption system Process 2.3 Vapor Compression System CHAPTER THREE: ... Continue reading---
CHAPTER ONE - [ Total Page(s): 2 ]CHAPTER ONEINTRODUCTION1.1 HISTORY OF REFRIGERATIONBefore the invention of mechanical and thermal refrigeration system, ice houses were used to provide cool storage for most of the year placed near fresh water lakes or packed with snow and ice during the winter, they were once very common (Pauken mike 1999). Natural means are still used to cool, also mountain sides run-off from melting snow is a convenient way to cool drinks, and during the winter, one can keep milk fresh much longer just ... Continue reading---
CHAPTER TWO - [ Total Page(s): 2 ]CHAPTER TWOLITERATURE REVIEW2.1 ABSORPTION SYSTEM OF REFRIGERATION The absorption system is difficult from the compression system. It used heat energy directly instead of mechanical system. It uses heat energy directly instead of mechanical to make change in the deduction necessary to complete as refrigeration cycle. The system may use element as source of heat (Paunken Mike, (1999) ). The system has fewer moving parts and operates relatively quietly. Such systems are used in commerc ... Continue reading---
CHAPTER FOUR - [ Total Page(s): 3 ]CHAPTER FOUR4.2 ASSEMBLY AND INSTALLATION The first stage of the assembly is the laggings materials and its facing the aluminum sheet.4.2.1 LAGGING MATERIAL AND FACING ALUMINUM SHEET The polystyrene is cut to thickness of 25mm. this is used to cover the internal of the cabinet. Then, the laying of evaporators through the polystyrene, one end of the evaporator is welded to the compressor to serve as inlet. The chemical sheet is used to face the polystyrene with the use of gum (e ... Continue reading---
CHAPTER FIVE - [ Total Page(s): 1 ]CHAPTER FIVERECOMMENDATION AND CONCLUSION5.1 RECOMMENDATION- The use of electric voltage regulator (stablizer0 recommended when using the freezer. - It is also recommended that the freezer should be used for domestic purposes.- Preventive maintenance should be carried out as at when due.- The project is unable to modification.- The project is a very good size, it improves students knowledge of thermodynamic engineering therefore it is recommended that this typ ... Continue reading---
REFRENCES - [ Total Page(s): 1 ]REFERENCES 1. Pauken Mike (1999), freezer (www. En.wikipedia.org (2010)).2. Adams Cecil *(2005), important of refrigeration (www. En. Wikipedia. Org, (2010))3. Albert Einsten (1999). Impact on life (www. En. Wikipedia. org).4. Pauken Mike (2001) Thermodynamic analysis (www. En. Wikiopedia. org ).5. Albert Einsten (2001) Refrigerant *(www. En. Wikipedia org ).6. Myers Richard (2003) types of compressor (www. Wikipedia. org). 7. Pauken Mike (1999) ... Continue reading---
