This happens when refrigerant enters the evaporator as a low temperature liquid at low pressure, and a fan forces air across the evaporator's fins, cooling the air by absorbing the heat from the space in question into the refrigerant.
Liquid refrigerant supplied to the coils by the expansion valve expands to a vapor as it absorbs heat from the air. Some liquid refrigerant must be supplied throughout the total length of the evaporator coils for full capacity.
Detailed Solution. The refrigerant at the entry to the evaporator is low pressure and low temperature liquid. The pressure is reduced in the capillary tube thus also decreasing the temperature. This low pressure, low temperature liquid is converted to low pressure vapours after absorbing heat from the evaporator.
A refrigerant is a high pressure liquid when it enters the metering device. The metering device decreased the pressure but didn't do anything to change the state of the refrigerant, so it is still a liquid. The compressor increases the refrigerant's pressure and the metering device decreases the refrigerant's pressure.
As refrigerant travels through the evaporator, it absorbs heat from the air. As it absorbs heat, it vaporizes. If the system operates according to design, the refrigerant will be 100% vapor as it nears the exit of the evaporator. Before leaving the evaporator, the vapor continues absorbing heat, becoming superheated.
Cold, low pressure refrigerant leaves the expansion valve and enters the evaporator coil. The blower fan moves warm indoor air over the coil, and the refrigerant absorbs heat from the air. As it does so, it turns into gas form.
Refrigerant can shift easily between liquid and gas states, which makes it ideal for ACs since it doesn't take significant amounts of energy to cause the phase shift. Refrigerant starts inside the compressor, where the reduction of volume turns it into a high pressure gas about 150°F.
The Thermal Expansion Valve (TXV) is an important piece of equipment in the HVAC industry. The valve is used to control the amount of refrigerant released to the evaporator section. In this way it controls the difference between superheat and the current refrigerant temperature at the evaporator outlet.
Refrigerant enters the evaporator in the form of a cool, low-pressure mixture of liquid and vapor (A). Heat is transferred to the refrigerant from the relatively warm air that is being cooled, causing the liquid refrigerant to boil.
What happens to the refrigerant as it passes through the metering device? The refrigerant drops in pressure and temperature as it passes through the metering device. A small portion of the refrigerant flashes to a vapor, cooling the remaining liquid.
Question #2:When the refrigerant exits the evaporator, what state is it in? In the evaporator, refrigerant absorbs heat from the indoor air to change state from liquid to vapor. This means that when the refrigerant leaves the evaporator, it is fully in the vapor state.
Upon entering the evaporator, the liquid refrigerant's temperature is between 40° and 50°F; and without changing its temperature; it absorbs heat as it changes state from a liquid to a vapor. The heat comes from the warm, moist room air blown across the evaporator coil.
The refrigerator's compressor increases the temperature and pressure of the refrigerant, then circulates it through condenser and evaporator coils as it transitions from a gas to a liquid, then back to a gas. Refrigerant absorbs heat as it undergoes chemical changes, cooling the freezer compartment as it circulates.
A thermal expansion valve or thermostatic expansion valve (often abbreviated as TEV, TXV, or TX valve) is a component in vapor-compression refrigeration and air conditioning systems that controls the amount of refrigerant released into the evaporator and is intended to regulate the superheat of the refrigerant that ...
In the refrigeration cycle, refrigerant flows from the condenser to the metering device through the liquid line. Remember that the previous component, the condenser, cools down the refrigerant until it turns into a liquid. So when refrigerant enters the metering device, it is in liquid state.
If the evaporator fan motor is broken, then cool air won't circulate properly. Sometimes you wind up with a freezer that's still pretty cold—because that's near where the coils are—but a fresh food compartment that isn't cold at all because the cool air isn't getting pushed there.
Principles of Refrigeration
For this reason, all air conditioners use the same cycle of compression, condensation, expansion, and evaporation in a closed circuit. The same refrigerant is used to move the heat from one area, to cool this area, and to expel this heat in another area.
C. After the evaporator, all of the refrigerant has heated beyond its boiling point, making it a superheated vapor. This means that from the evaporator, entering into the compressor, the refrigerant is in superheated vapor state.
The compressor
Compression is the first step in the refrigeration cycle, and a compressor is the piece of equipment that increases the pressure of the working gas. Refrigerant enters the compressor as low-pressure, low-temperature gas, and leaves the compressor as a high-pressure, high-temperature gas.
Dirty coil
Over time, your system's evaporator coil will become covered in dust, dirt, grime, and more. This prevents it from getting the airflow it needs to properly move heat, which means that the system could then freeze over.
Frosting on the exit side of the evaporator coil, in combination with a noisy compressor can be a sign of flooding. Flooding occurs when the TEV is letting in more refrigerant to the evaporator coil than what can be evaporated off.
If your air conditioner were filled with water, it would take a huge amount of energy to move heat from inside your home to the outside. Water just takes too much pressure, time, and energy to compress to the point where it will absorb heat properly. Refrigerant does this job much better.
After leaving the evaporator, the vaporized refrigerant flows through the compressor. In the compressor, the pressure of the vaporized refrigerant is raised to a point at which it can be condensed by some relatively warm fluid, e.g. water. The compressor removes the refrigerant vapor.
Theoretically, Freon can last forever. It is not burned up like fuel. When an air conditioning system is in top shape, the refrigerant will be continually recycled within a closed system, to cool your home. However, as the AC tubing ages and wears out, it tends to develop leaks in the system.