i would like to know what materials do we use to make a refrigerator?

Answer 1

A refrigerator (often called a "fridge" for short) is a cooling appliance for the storage and preservation of perishable food; food kept in a refrigerator lasts longer than that left at room temperature as the cold inhibits bacterial growth. A refrigerator maintains a cold temperature above the freezing point of water. The refrigerator is a relatively modern invention amongst kitchen appliances. It replaced the common icebox which had been a household item for almost a century and a half prior, and is sometimes still called by the original name "icebox".

Essential items required are

Compressor
Evaporator
Condensor

You can keep these items based on your Refrigerator design. Condensor surface should have max air flow to work system effectively.

Answer 2

The gas that really cools is a freon. It evaporates under normal atmospheric pressure and temperature around zero oC. However it becomes liquid under pressure about 1 ATM and room temperature. The refrigerator compressor circulates freon through the narrow (tube) opening. Before the opening the freon under pressure in the liquid state. After the opening there is no pressure the freon evaporates which causes the cooling effect. So if you place the narrow opening inside the thermally insulated box (refrigerator) it will cool the interior. During the compression in the wider tube the freon liquidizes and heats up. If you place this tube outside (behind) the fridge the wider tube will cool to the room temperature that will be the temperature of the liquid freon before the narrow tube. To make it thermally insulated the fridge walls and doors are usually filled with styrofoam which is very good insulating material.

Answer 3

materials used are as follows
case - usually painted steel
insulation - usually EPS or expanded polyestyrene
liner (plastic surface inside) various plastics, blow moulded.
'Furniture' shelves, drawers etc - various plastics, glass, plastic coated steel
compressor - mild steel, other alloys, oil filled
Coolant - usually pentane, older used CFC based refrigerants