How does an esky keep food cold?

Eskys, also known as coolers, use passive cooling methods to keep food and drinks cold. They achieve this through several components and mechanisms:

1. Insulation: Eskys are typically made of materials that provide good insulation, such as polystyrene, polyurethane foam, or even vacuum-sealed panels. These materials help to minimise heat transfer between the warm external environment and the cool interior of the esky.

2. Reflective Surfaces: The insides of eskys are often lined with reflective materials, such as aluminium foil or metallised film. These surfaces help to reflect radiant heat back towards the source, keeping the interior cooler.

3. Airtight Seals: To maximise cooling efficiency, eskys are designed with tight-fitting lids and gaskets that create an airtight seal. This prevents warm air from entering the esky and reduces heat exchange with the surroundings.

4. Ice or Cold Packs: To actively cool the contents of the esky, ice or reusable cold packs are placed inside. As the ice melts or the cold packs release their coldness, they absorb heat from the surrounding air and keep the temperature inside the esky low.

5. Drainage System: Eskys usually have a drainage plug or spout at the bottom to allow melted ice water to drain out. This prevents the water from accumulating inside and taking up space that could be used for storing food and drinks.

By combining these elements, eskys create a microenvironment that is insulated, cool, and free from warm air circulation. This allows food and beverages to remain chilled for extended periods without the need for electrical power or external refrigeration.