The refrigeration system of a cake display case consists of a compressor, condenser, capillary tube (throttling element), and evaporator.
The compressor is the heart of the cake display case's refrigeration system. Its selection requires consideration of the evaporation temperature (cake display cases are for medium-temperature applications, typically around -5 to -10 degrees Celsius), refrigerant (domestic manufacturers primarily use traditional R22 and environmentally friendly R134a refrigerants), and starting method. Due to the high commercial nature of cake display cases, the insulation of the glass is somewhat insufficient, and frequent door opening leads to cooling loss and frequent compressor start-stop cycles. Furthermore, the unstable power supply voltage in China necessitates selecting a compressor with capacitor start (CSIR, CSR) to ensure reliable startup.
The condenser is mostly finned and equipped with an axial fan. To save space, the condenser in small display cases is often made long and narrow with a compact fan. The evaporator is installed below the display area. To maintain a high humidity level (80-90%) inside the case, its fin spacing is designed to be relatively large. Some manufacturers use two different fin spacings on the same evaporator to optimize the cooling effect.
To keep cakes fresh, the display case needs to maintain a temperature of +2 to +8°C and a humidity of 80-90%. If insufficient humidity is caused by refrigeration system mismatch, some designs will place water cups inside the case to increase humidification. However, lowering the evaporation temperature to achieve high humidity will reduce compressor efficiency and increase the risk of malfunction.
The condensate produced by the evaporator flows into a drip tray installed next to the compressor. The compressor exhaust pipe, coated with a special material, winds through the drip tray, using residual heat to evaporate the moisture; therefore, cake display cases typically do not require an external drain pipe.
