Automatic melting , automatic melting or own melt is a technique that regularly thaws evaporators in the refrigerator or freezer. Tools that use this technique are often called frost free , frostless or no-frost .
Video Auto-defrost
Mekanisme
The defrost mechanism in the refrigerator heats up the cooling element (coil evaporator) for a short time and melts the frost formed on it. The resulting water flows through the channel at the rear of the unit. Liquidation controlled by electronic or electric regulator: For every 6, 8, 10, 12 or 24 hours of compressor operation, turn on the heating heater for 15 minutes to half an hour. The defrost heater, which has a typical power of 350 W to 600 W, is mounted just below the evaporator in the upper and lower freezer models and below and sometimes also in the middle of the evaporator in a side by side model. This can be protected from short circuits by using smelted links. In the older refrigerator, the timer keeps running. In newer designs, the timer only runs as the compressor runs, so the more refrigerator doors close, the less the heater will light up and the more energy it will store. A defrost thermostat opens a heating circuit when the evaporator temperature rises above a pre-set temperature of 40 ° F (5 ° C) or more, thereby preventing overheating of the freezer compartment. Ice-melting timers such as compressors or freezer heaters are on, but not both at the same time.
In the freezer, air is circulated using one or more fans. In a typical design the cold air of the freezer compartment is supplied to fresh food compartments and recirculated to the freezer compartment. Air circulation helps sublimate ice or ice that may form on frozen objects in the freezer compartment.
Instead of the traditional cooling element embedded in the freezer liner, the auto-defrost element is behind or below the liner. This allows them to be heated for a short period of time to throw ice without heating the contents of the freezer.
Alternatively, some systems use hot gas in the condenser to melt the evaporator. This is done by using a crosslinked circuit with a three-way valve. The hot gas quickly heats the evaporator and melts it. This system is mainly used in commercial applications such as ice cream display.
Maps Auto-defrost
Apps
While this technique was originally applied to the refrigerator compartment, it was then used for freezer compartments as well.
Refrigerators/freezers that use self-defrosting into the refrigerator are usually called "partial free" or semi-automatic melting (some brands call it "Auto Defrost" while Frigidaire refers to semi-automatic). -automatic model as "Cycla-Matic," Kelvinator often calls this model "Cyclic Defrost"). This refrigerator usually has a pan under the water from the frost that melts in the refrigerator part of the yawning.
Freezers with automatic melting and a combination of refrigerator/freezer units that also use their own melting into their freezer compartments are called "ice-free". The latter usually displays the air connection between two compartments with the air duct to the refrigerator compartment arranged by the silencer. In this way, the controlled part of the air coming from the freezer reaches the refrigerator. Some older models have no air circulation between the freezer and the refrigerator part. Instead, they use independent cooling systems (eg evaporator coils with frost-free heaters and circulating fans in freezers and cold-plate evaporators or open coils in the refrigerator.
Ice-free refrigerated/freezer units typically use heating elements to liquefy their evaporators, pots to collect and evaporate water from melting frost from cold plates and/or evaporator coils, timers that turn off compressors and turn on ice melting elements usually from once up to 4 times a day for a period usually ranges from 15 to 30 minutes, a freezer thermostat that turns off the heating element before the temperature rises too much while the timer is still in the defrost phase. Some models also have channel heater to prevent ice from blocking the drain.
Other early types of refrigerators also use hot gas liquefaction instead of electric heaters. This reverses the evaporator and condenser side for the liquefaction cycle.
Some newer refrigerator/freezer models have computers that monitor how many times each door is opened and use this data to control defrost scheduling thus reducing power usage.
Benefits
- There's no need to defrost the ice manually, so power consumption will not increase over time.
- Food packaging is easier to see.
- Most frozen foods will not stick together.
- Odor is limited, especially in ice-free equipment because the air is always circulating.
- Better temperature management.
Loss
- The system can be more expensive to run when high usage and if the fan continues or starts running when the door is opened.
- Thermal snippet security devices are required to prevent overheating of the heating elements.
- Increased electrical and mechanical complexity compared to chest freezers or chest freezers, making it more susceptible to component failure.
- The temperature of the freezer contents increases during the liquefaction cycle, especially if there is a light weight in the freezer. This can cause a "freezer burn" on articles placed in the freezer, from partial melting, then freezing
- On a hot day, damp condensation will sometimes form around the refrigerator door.
- The ice melt can not be completed at the disbanding cycle of the disbursement time to normal operation (especially in Hot, damp conditions with frequent door openings), leaving frost on the evaporator coils. This condition can cause "icing up" which will disrupt the operation of the refrigerator.
In the laboratory, self-defrosting freezers should not be used to store certain subtle reagents such as enzymes, because the temperature cycle can lower them. In addition, water can evaporate from a container that does not have a very tight seal, changing the concentration of the reagent. Self-defrosting freezers should not be used to store flammable chemicals.
References
External links
- Original 1927 Patent
- Ice page on howstuffworks
- www.appliance411.comÃ, - How does the ice freeze refrigeration system work? (annotations and animated diagrams)
Source of the article : Wikipedia
0 Comments