ABSTRACT
The
design and construction of s refrigerating unit is handled from the knowledge
of the working principles of laws of thermodynamics.
The size of the containing vessel i.e
the case as established to be of 45cm by 32 cm in dimension. The Angle iron
mild steel to used in the fabrication and welding. The box case of two layers
are fabricated. Plastic (cooler) box is then
placed inside the upper part with the other parts of the refrigerator
were brought in. they were all fixed onto a wooden base with all the connections
(electrical) made.
The capacity of the refrigerator is
based on the workdone by the compressor which is O.I hp in specification. The
size of the components used are
i.
Condenser: The size is 0.1hp and it is a plate type
condenser with extended surface.
ii.
Compressor: The size is 0.1hp (75 watts)
iii.
Copper wire: it is of 0.5cm in diameter and the total
copper wire length is about 600cm (1½ roll)
The
introduction of cooling fluid and filling of the compressor enabled the
compressor to start functioning when connected to electricity using a 13 AMP
rated socket
The interior of the plastic box is
lined with dominium box with tubes arranged in convolution around it. This
world effectively and cooled the water dropped into it. It compares favorably
with the ones in the market.
TABLE OF
CONTENT
TITLE PAGE
LETTER OF
TRANSMITTAL
APPROVAL/CERTIFICATION
DEDICATION
ACKNOWLDEGEMENT
ABSTRCAT
TABLE OF
CONTENT
CHAPTER ONE
1.0
INTRODUCTION
1.1 SCOPE OF THE PROJECT
CHAPTER TWO
HISTORY OF
REFRIGERATION
TYPES OF
REFRIGERATING DEVICE
USES OF
REFRIGERATION
CHAPTER THREE
SEQUENCE OF
OPERATIONS
SELECTION OF
REFRIGRANTS
CONSTRUCTION
PROCEDURE
ECONOMIC
ANALYSIS
\CHAPTER FOUR
4.1
CONCLUSION
4.2
RECOMMENDATIONS
REFERENCES.
CHAPTER ONE
1.0 INTRODUCTION
Refrigeration
is the process of lowering the temperature of a substance below that of its
surrounding.
Refrigeration is the practical
application of the first and second law thermodynamics. Comprehensive
understanding of the basic principles of thermodynamics is crucial for full
understanding of basic operation of refrigerator. The first law states that the
energy can neither be created nor destroyed. If energy of 2.5J appears in one
forms it appears in another without a corresponding decrease of energy on the
other form. The second law states that no system can receive heat at a given
temperature and reject it at a higher temperature without receiving work from
the surrounding heat always flow from Warner to cooler body. Through
consideration of these laws, the ideal refrigeration cycle are considered. The
carnot cycle is reversible and consist of adiabatic compression witherma
rejection of heat, adiabatic expansion and wothermal addition of heatl the
carnot cycle is unattainable ideal which serves as a standard of comparison and
it provides a convenient guide to the temperature that should be maintained to
achieved effectiveness. The efficiency or coefficient of performance (C.O.P.)
of a carnot cycle depends on the temperature at which heat is added and
rejected.
Therefore,
C.O.P
= T1
T2
– T1
Where T1 = Evaporation temperature
T2 = Conducting temperature
In actual
refrigeration there will be issues causing C.O.P to be less than that for ideal
cycle. The basic methods of refrigeration like the mechanical refrigeration
ejector (steam jet) refrigeration absorption refrigeration uses similar process
for obtaining refrigeration effect. That is evaporation in the evaporator,
condensation in the condenser, the main difference is in the way used
refrigeration being done. The most compression. The cycle efficiency can be
ignored in a number of ways.
1.
Multistage system: When evaporation and condensing
temperature (pressure) difference is large, it is prudent to separate
compression into two stages. The use of multistage system open up the
opportunity to use flash gas removal and inter cooling as a measure to improve
performance of the system
2.
Cascade system: This appears in situation where the
evaporating temperature is very low (below 600c). the refrigerant is
used to achieve the cooling. The liquid with low boiling points are used as refrigerants.
1.1 SCOPE OFD THE PROJECT
The
scope of this project is mainly concerned with the design and construction of a
refrigerating unit that has a very performance level and with the cost of
fabrication lower than that of existing prototype
A good refrigerator is one that has
all the basic components of compressor, condensers, fan motor, copper tubes and
other. This project must apply all the principles of refrigeration.
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