CHAPTER ONE
REFRIGERATION
Refrigeration is defined as a process of removing heat from a substance or space in other to make it cooler. More so, it is the branch of science which deals with the process of reducing and maintaining the temperature of the surrounding.
Generally, for a space to be cooler, it must lose heat to another substance. Also for a space or material to get hotter, it must absorb heat from another substance. Thus, heat is the characteristic agent of heating and cooling. Consequently, for heat to flow, there must be a medium or mode for the transmission. This always follows from high temperature region to low temperature region/bodies.
The modes of heat transmission are conduction, convection and radiation. Conduction and convection are extensively involved in domestic refrigeration.
In refrigeration process, there is always a body employed as the heat absorber or the cooling agent which may be near to the material or space being cooled or space being cooled or in direct contact with the material being cooled depending on the required final effect such a cooling agent is known as the Refrigerant. The refrigerant circulates around the evaporating and condensing regions. In other to maintain a constant refrigeration process it does it work by evaporating and condensing. When it loses the absorbed heat to return to its original liquid or solid rate, as the case may be classified a s sensible heat or latent heat, (depending on the physical effect on the refrigerants. Generally, when a mass or body absorbs heat the following physical changes takes place.
1. The mass expands or increases in physical dimensions as the molecules resonate within a wider range
2. The temperature increase (as the molecules gain more internal lunatic energy)
3. There is a change in phase (as the mass changes from solid to liquid and consequently to gas and vice versa)
4. The specific density decreases (as the mass remain constant while the volume increase) etc.