The liquid line is an important part of the refrigeration system and it transports the refrigerant from the metering device to the evaporator.

A purge unit is used to remove trapped air from a low-pressure system from the top of the condenser. The purge unit has a pump that creates a vacuum inside the condenser. This vacuum draws the trapped air out of the condenser and into the purge unit. The purge unit then vents the trapped air to the outside.

A larger diameter hose will allow for a faster flow of refrigerant, which will result in quicker evacuation of the system.

Nitrogen is an inert gas, which means that it does not react with other substances. This makes it a safe and reliable choice for purging or pressurizing refrigerant or air conditioning systems.

The TXV valve stem controls the flow of refrigerant into the evaporator. When the stem is turned clockwise, it closes the valve, which reduces the flow of refrigerant. This causes the refrigerant to vaporize more completely in the evaporator, which increases the superheat.

Miscibility refers to the ability of a refrigerant to mix with a lubricant. A refrigerant that is miscible with a lubricant will mix with the lubricant and form a single phase. This helps in improving the efficiency of the system.

Reciprocating compressors are typically used in large refrigeration systems, such as those used in commercial buildings and industrial applications. reciprocating compressors are a reliable and efficient type of compressor that is used in a variety of applications. However, they can be noisy and require regular maintenance.

Relative humidity (RH) is the amount of water vapor in the air compared to the maximum amount of water vapor that the air can hold at a given temperature. The wet bulb temperature (WBT) thermometer bulb is covered with a wet cloth.

Dalton’s law of partial pressures

Relays are typically used for low-current applications, such as controlling small motors or lights.  Contactors are typically used for high-current applications, such as controlling motors, air conditioners, and other large loads.

The total pressure of the air in the duct is the sum of the static pressure and the dynamic pressure. The total pressure determines the amount of force that is required to move the air through the ductwork.

A Variable Frequency Drive (VFD) system is a device that controls the speed of an electric motor by adjusting the frequency of the electrical current. This allows the motor to operate at different speeds, which can be used to control the refrigeration system’s capacity

Some common examples of sublimation include dry ice, iodine, and camphor

The latent heat of fusion is the amount of heat required to change a solid into a liquid without changing its temperature. For water, the latent heat of fusion is 144 Btu/lb.

The flue gases are a mixture of carbon dioxide, water vapor, and other combustion products which are hot and contain a lot of energy. When the flue gases pass through the tubes, they heat the water, causing it to turn into steam. The steam is then used to heat water or other fluids, or to generate power.

Convection is the transfer of heat between a solid surface and a fluid (gas or liquid) that is in motion. The fluid moves over the surface and carries away heat by conduction and diffusion.