what is a refrigerator evaporator – Home Efficiency Guide

When it comes down to the refrigerator system, the refrigerator evaporator plays a big role in refrigerator cooling. A refrigerator evaporator works alongside other refrigerator system components, such as the compressor, expansion device, and condenser. The basic function of a refrigerator evaporator is to remove heat from the air, water, and other items inside the refrigerator. The refrigerator evaporator acts as a heat exchanger, which aids in transferring heat from items and making it cool. How a Refrigerator Works The refrigerator evaporator is one part of the refrigeration cycle that makes the inside of your refrigerator cold. After the refrigerant gas has gone through the condenser coils located at the back of the refrigerator, it starts to cool down and turn into a liquid. It’s at this liquid stage that the refrigerant reaches the expansion valve. The expansion valve controls the amount of cooled refrigerant gas that’s released into the refrigerator evaporator. As that gas enters the refrigerator evaporator, it’s pulled forward by the air pressure that’s created by the compressor on the opposite side. During this process, the refrigerant absorbs heat found by the evaporator, especially in the air that’s found inside the refrigerator’s food compartments. Some refrigerator models utilize fans to blow the air from inside the food compartments toward the evaporator coil to quickly absorb heat. After it has absorbed as much heat as possible, the refrigerant is then pumped back into the compressor's refrigeration cycle. Importance of Refrigerator System The importance of a refrigerator system in our lives is well-known by everyone, especially when it’s warm outside. Refrigerators help keep water and food cold and fresh. Food stays fresher in a cold refrigerator because the cold air slows bacteria's formation on the food, which means that it takes longer for the food to grow worse. The refrigerator evaporator plays a huge role in the cooling system of a refrigerator. Types of Refrigerator Evaporator There are two types of refrigerator evaporators that help in the heat exchanging process. Let’s take a look at each type: Forced Convection A forced convection refrigerator evaporator helps force the liquid that needs to be cooled down through a pump or fan over the refrigerator evaporator. Natural Convection A natural convection refrigerator evaporator helps cool down the flow of liquid inside the refrigerator in a natural way. Natural convection works because there’s a difference between the density of a chilled and warm liquid. The Construction Types of a Refrigerator Evaporator When you think about the different construction types of refrigerator evaporators, you’ll find three construction types. Let’s take a closer look at each type. Bare Tube Refrigerator Evaporator This construction type of a refrigerator evaporator is designed so the evaporator's entire surface is in contact with the evaporating refrigerant found inside the refrigerator system. Plate Surface Refrigerator Evaporator This construction type works the same way as the bare tube construction type and has the same concept of having surface contact with the evaporating refrigerant. However, a plate surface refrigerator evaporator is found in different refrigerator systems than bare tube evaporators. Finned Refrigerator Evaporator This construction type is used over the bare tube coils. The fins are metal plates made from aluminum. The construction design of a refrigerator evaporator will depend on several factors. The three main factors that play a role in which construction type is used in a refrigerator system: refrigerant and liquid-vapor, temperature, and pressure drop. How to Get Rid of Frost from the Refrigerator Evaporator Taking care of your refrigerator by performing maintenance regularly can extend your refrigerator's life and improve the unit's performance. Most of the newer refrigerators don’t require manual defrosting because they have automatic defrosting systems that reduce the frost build up on the refrigerator evaporator. However, older refrigerators require the manual removal of frost from the freezer and the evaporator coil. A build-up of frost can reduce the cooling ability of your refrigerator and cause damages to the units. There are three ways that you can defrost your refrigerator evaporator coils. Thermostat Defrosting Set the refrigerator thermostat to the desired temperature for both the refrigerator and freezer. Place a pot or pan under the exit tube to catch the water runoff. The exit tube is located at the back of the unit near the bottom. When the desired temperature is reached, the compressor will switch off, and the frost in the freezer and evaporator coil will start to melt. Manual Defrosting When doing a manual defrost, you need to remove the ice from the freezer and remove all food from the unit. Remove the baskets and trays from the refrigerator too. Push towels under the unit, especially under the door, so it will collect water during the defrosting process. Set the thermostat to zero and then unplug the unit. Open the doors to let warm air circulate in both the refrigerator and freezer. Dry the inside of the refrigerator and wipe off the refrigerator evaporator coils too. Plug the unit back in and set the thermostat to the desired temperature and replace all the food after the unit has reached a temperature at or below 42 degrees F. Heater Defrosting Remove all food from the refrigerator, along with all the baskets and trays. Turn the thermostat to zero; this is when the heater will turn on and blow warm air into the unit. Open the refrigerator doors to let warm air circulate through the unit. Empty the water collecting tray as needed; this tray is located at the back of the unit near the bottom. Once the defrosting process is completed, reset the thermostat and wait until the unit has reached a temperature at or below 42 degrees F before you return the food. Related Reading: Condensation in Refrigerator: Here’s How to Fix ItWhy Does My Refrigerator Keep Freezing Up?Why Is My Refrigerator Drain Pan Full of Water? 5 Key CausesRefrigerator Keeps Tripping Breaker: Troubleshooting Guide