DOMRAC 1

• Discipline

  Good Taste<|>Excellence
• This module was designed and written with you in mind. It is here to help you master the Refrigeration and Airconditioning.
• Lessons in this module

  • LESSON 1: Development of refrigeration
  • LESSON 2: Principles of refrigeration
  • LESSON 3: States of matter
  • LESSON 4: Temperature
  • LESSON 5: Methods of heat transfer
  • LESSON 6: Pressure and Heat
• Learning objectives

  • Have knowledge in the development of refrigeration
  • Explained the principle of refrigeration
  • Identify the composition of refrigeration cycle
  • Explain how heat transfer is done
  • Demonstrate the process of applying heat and pressure
• Preservation of food is one of the most important uses of refrigeration. Food lasts longer when kept in cool area. Studies shows that food have microbes that multiply faster in some warn places. This multiplication of microbes has been recognized as the major cause of food spoilage. At the temperature of 50 Degrees or less, microbes could not multiply at all.
• Reasons for using a refrigerator

  • to preserve food
  • to cool drinks
  • to make ice
  • to store food
  • to keep food fresh
• Refrigeration was used by Chinese when they discovered that ice could improve the taste of drinks. The early Egyptians found out that water could be cooled by placing it to a jar on the roof top at sundown. The Greek and the romans place their food in the snow for preservation purposes. In warm places, people place their foods in vessels immersed in stream of water or by storing them in holes dug on the ground for preservation.
• Icebox


  First refrigerator introduced to the society
• It was in 1834 when an American engineer, Jacob Perkins introduce the first patent for a practical ice making machine in London. This machine was used successfully in meat packing plants. Within the next 50 years, ice maker is manufactured in united states, France, and Germany and in other countries. Nowadays, refrigeration is not only put in used for the preservation of foods. It is likewise used in chemicals, metal, medicine, gases, machines, tools, and electronics devices.
• Main parts of an icebox


  • Insulation
  • Ice compartment
  • Drain pipe
  • Shelves
  • Door
• 1834 model refrigerator


  Ice box
• What is the given name of the first refrigerator?
• Who is the inventor of the first mechanical refrigerator?
• What is the purpose of refrigerator?
• Who is the first user of icebox?
• Refrigeration


  Low temperature
• Icebox


  First refrigerator
• Preservation


  Freezing
• Ice maker


  Develop in 1834
• Freezing


  Circulation of refrigerant
• Compressor


  Increases pressure and temperature of refrigerant
• Evaporator


  Absorbs heat from inside the refrigerator cabinet
• Condenser


  Discharges heat absorbed in the evaporator to the outside
• Expansion valve


  Reduces the pressure of the refrigerant
• Refrigerant


  Fluid that easily boils at a lower temperature, absorbs heat in the evaporator and discharges it in the condenser
• Refrigeration cycle


  Refrigerant absorbs heat in the evaporator, compressor increases pressure and temperature, condenser discharges heat, expansion valve reduces pressure, cycle repeats
• What is refrigeration cycle?
• What are the components of refrigeration cycle?
• Condenser


  Discharges heat
• Expansion valve


  Reduces pressure
• Refrigeration cycle


  The process of cooling and removing heat from an enclosed space or from a substance, and transferring that heat to a place where it can be disposed of or used
• Components of refrigeration cycle

  • Condenser
  • Expansion Valve
  • Refrigerant
  • Evaporator
  • Compressor
• Refrigeration system


  Circulation of refrigerant in the system
• Condenser


  Pulls out heat
• Expansion Valve


  Controls pressure
• Refrigerant


  Circulates in the system
• Evaporator


  Absorbs heat
• Compressor


  Produces pressure
• Function of each component in refrigeration cycle
• Matter


  Anything that has weight and occupies space