CORE AREA 2 RESOURCE MANAGEMENT AND CONSUMER STUDIES
Humidity-controlled drawers
• A low humidity setting is used to prevent the rotting of fruit and vegetables that naturally release ethylene gas, e.g. apples or celery. The low humidity setting creates
Humidity refers to the amount of water vapour in the air.
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an opening in the drawer that allows the ethylene gas to escape.
• A high humidity setting is used for fruit and vegetables prone to wilting or moisture loss, e.g. strawberries or spinach. The high humidity setting keeps the drawer sealed, retaining moisture and keeping fruit and vegetables crisper and fresher for longer.
Ice/water dispensers • Water is plumbed from the mains water supply, filtered and kept chilled. Some water is taken to form ice cubes or crushed ice.
• It is operated by a push lever dispenser on the front of the refrigerator.
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Set out the results of a study you have carried out on a refrigeration appliance. Refer to: • modern features. (9) HL
Working principle of a refrigerator
• Compressor: the compressor is found at the base of the refrigerator. It contains the gas refrigerant isobutene. A motor or pump connected to the compressor forces the gas refrigerant into the condenser above.
• Condenser: the condenser cools the gas refrigerant and condenses it into a liquid. It is then sent to the evaporator above. The cooling fins at the back of the refrigerator radiate or release heat generated during the process, keeping the condenser cool.
Evaporator (GAS)
Tray Cooling fins
Condenser (LIQUID)
Motor Thermostat
• Evaporator: the evaporator, found at the top of the refrigerator, rapidly evaporates the liquid refrigerant into a gas by drawing heat from the fridge cabinet. This cools the internal temperature of the refrigerator cabinet to 3–4°C. The gas refrigerant then returns to the compressor and the cycle begins again.
• Thermostat: the thermostat is connected to the compressor and maintains the constant internal temperature of 3–4°C within the refrigerator cabinet by turning on and off the motor when needed, e.g. if the door is left open.
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State the function of each of the following refrigerator parts: • compressor
• condenser • evaporator. (6) HL
Set out details of a study that you have undertaken on a refrigeration appliance. Refer to working principle. (12) HL
