koelkasten

Koelkasten are household appliances designed to keep food and drinks cold, slowing bacterial growth and extending shelf life. Most modern koelkasten operate on a vapor-compression refrigeration cycle in which a circulating refrigerant is pressurized by a compressor, condensed into a liquid, expanded through a valve, and evaporated to absorb heat from the interior. The result is a controlled interior temperature typically between 2 and 5°C for refrigeration and around -18°C for freezing. Core components include the compressor, condenser, expansion device, and evaporator.

Units can be freestanding or built-in and come in various configurations, such as top-freezer, bottom-freezer, side-by-side, or French-door designs. Frost-free (no manual defrost) models automate ice and condensation management, while manual-defrost units require periodic emptying and scraping. Energy efficiency varies, with labeling or ratings indicating annual energy consumption; modern models emphasize insulation and efficient compressors. Storage features include adjustable shelves, door bins, drawers, and humidity-controlled crisper compartments.

Environmental and history: Refrigerants have evolved due to safety and climate concerns; early refrigerants damaged ozone; international agreements phased them out; contemporary koelkasten use hydrofluorocarbons (HFCs) with lower ozone impact or natural refrigerants like isobutane (R-600a) in some markets. Maintenance includes ensuring seals are intact and coils are clean; proper disposal is important due to refrigerants. The development of domestic refrigeration began in the early 20th century, and widespread use followed after World War II, with ongoing improvements in efficiency and features.