In the past, refrigerators worked using a combination of ice and specialized chambers to keep food cold. These early refrigerators are often referred to as "iceboxes" or "ice chests." Here's how they worked:
Insulation: The main body of the refrigerator was made of wood or metal and was well-insulated to minimize heat exchange with the surrounding environment. The insulation helped to keep the cold temperatures inside and prevent the external heat from entering.
Ice compartment: Inside the refrigerator, there was a compartment specifically designed to hold a block of ice. This compartment was located at the top or on the side of the refrigerator.
Ice delivery: Regularly, an ice delivery person would bring large blocks of ice to the home. These blocks were usually sourced from frozen lakes during the winter and stored in icehouses to last through the summer months.
Drip tray: The ice compartment had a drip tray at the bottom to catch the melting water from the ice. This prevented the melted ice from accumulating and spoiling the stored food.
Cooling effect: As the ice melted, it absorbed heat from the surrounding air inside the refrigerator. This process of absorbing heat is an endothermic reaction, and it helped to maintain a consistently cool temperature inside the icebox.
Thermometer: Some iceboxes had built-in thermometers to monitor the temperature, ensuring that the food was kept at a safe level to prevent spoilage.
Regular maintenance: To keep the refrigerator working efficiently, homeowners needed to replace the melted ice regularly. The frequency of ice replacement depended on various factors like the external temperature, insulation quality, and the amount of food stored.
Iceboxes were a significant advancement over earlier methods of food preservation, such as using cellars or ice houses, which were less effective in controlling temperatures. However, they were not as convenient or efficient as modern refrigerators powered by electricity and refrigerants, which led to the widespread adoption of electric refrigerators starting in the early 20th century.