ABSTRACT
This wrote up is a detail of the processes for the physical realization of the design and construction of mobile deep freezer.
It is divided into chapters which discussed expensively the practical refrigeration cycle with rull attention given to design factors working principals and choice of material.
Also considered were fabrication assembly and safely requirement
INTRODUCTION
Firstly refrigeration in the process of removing heat from a substance or space in order to make it cooler.
A mobile deep freezer is not different from all other refrigeration the only difference is that it can be moved easily by wheel or rollers to different places in a given time with less force applied to effect the movement.
In refrigeration the three mode of heat transfer is employed causing heat to flow from high temperature regions to low temperature regions. The substance used to carry heat in the refrigeration is known as the refrigerant.
Refrigerant is the cooling agent in refrigeration. It makes indirect contact with the substance to be cooled. It is circulated in the refrigeration circult and the attendant change of state from liquid to vapour brings about the necessary cooling that is required in the system which also involves INTENT OR SENSIBLE HEAT.
Refrigeration is accompanied by various method such as the vapour compression system absorption system and steam jet refrigeration cycle.
Refrigeration contributes greatly to the raising of living standards of people its uses can not be over emphasized in this book. The most common used and one that is readily recognized is the preservation of food. Most products in our homes businesses industries laboratories hospitals farms etc are affected by refrigeration.
Its application is also extended to other areas apart from food in medicine it is used in blood banks for antibiotic for making ice for compression and low temperature surgery for presenting certain tissues that pathologist work on. It is very essential in genetic engineering to preserve sperms and eggs or longer years before they work on them to bring life.
Deep freezer is an Electro- mechanical appliance which maintains the temperature of substance space or material as requires by the user it produce artificial cooling. It operates on the principal of reversed cannot cycle that is to say that it absorbs heat from a low temperature and rejects it to a high temperature region.
The compressor provides the conversion of energy that is used in circulating the refrigerant round the circult.
The crankshaft drives the piston through the connecting rod and it’s moved by the tongue produced by electric motor. The pumping effect of the piston produces the high pressure on the refrigerant which sets it in motion. In the causes of circulation and attendant change of state the refrigerant returns to the initial state and ready for another cycle.
In a deep freezer the condenser performs function similar to that of the radiator in an auto mobile. It cools the hot refrigerator gas by giving out hear to the dryer which traps moisture that can block the metering device. The liquid refrigerant passes through the metering device which expands the liquid into the evaporator pipe which is of large cross sectional area.
The pipe is laid on the inside of the deep freezer
A lot of insulation is done to isolate the refrigerated space from the surrounding its heating effect.