【Mechanical Equipment Technology Edition】Daily Question 201805012: Refrigeration Systems – Refrigeration Equipment (3)

A condenser, also known as a “liquidator,” is a heat exchanger in which steam releases heat and is thus liquefied. In a refrigeration system, it is the heat exchanger through which the refrigerant releases heat outside the system. The superheated refrigerant vapor coming from the compressor enters the condenser, where it transfers heat to the surrounding medium—air or water—and it itself condenses into a liquid state due to the release of latent heat. Based on the cooling medium used, condensers can be divided into air-cooled (or air-cooled type) and water-cooled types. 　　 　　An evaporator is a heat exchanger in which the liquid refrigerant evaporates. In a refrigeration system, the evaporator is the device that generates cold. It belongs to the type of heat exchanger with partition walls; the heat from the medium being cooled is transferred to the refrigerant through the wall of the tubes. The refrigerant then evaporates at low temperatures, thereby removing heat from the evaporator. Evaporators in refrigeration systems can be divided into two main categories based on the cooling method: direct cooling and indirect cooling. Both cool air or objects; the latter first cools the coolant—brine or fresh water—and then cools the air or objects. The former cools down quickly, has minimal heat loss, and features a compact design; it is mainly used in refrigerators and freezers. In small cold storage units, compact refrigeration equipment, and various air conditioners; the latter is used in larger air conditioning and freezing systems.

Hello, I would like to ask why there is a volume ratio adjustment What is the use of this adjustment?

An evaporator is a device in which the refrigerant liquid evaporates into a gas, thereby absorbing heat from the surroundings； A condenser is a device that condenses refrigerant gas into a liquid to release heat outside.

1. “Cooling process”: The liquid refrigerant absorbs heat from the object to be cooled in the evaporator, where it vaporizes into high-temperature, low-pressure steam. This steam is then drawn in by the compressor, compressed into high-pressure, high-temperature steam, and sent to the condenser. There, it releases heat to a cooling medium (water or air), condensing back into a high-pressure liquid. The liquid is then throttled through a throttle valve to become a low-pressure, low-temperature refrigerant, which once again enters the evaporator to absorb heat and vaporize, thus completing the cycle of cooling. 2. Functions and differences between condensers and evaporators: Both condensers and evaporators are types of heat exchangers. Heat exchange refers to a device that enables heat transfer between two or more fluids at different temperatures; it is therefore also known as a heat exchange unit. Therefore, although there are various structural designs for condensers and evaporators, their working principle is the same: they are all devices that exchange heat between the refrigerant and the external medium flowing over their surface, in other words, they are all types of heat exchangers. In terms of the factors affecting heat transfer, condensers and evaporators are similar; their heat transfer capacity is related to the heat exchange area, the temperature difference for heat transfer, and the heat transfer coefficient. However, the working principles of the condenser and the evaporator are different; the condenser is used to cool a medium and cause it to liquefy, releasing heat in the process ； An evaporator is a device in which the medium absorbs heat and vaporizes, thereby taking in heat from the surroundings; in other words, the refrigerant changes from a gaseous state to a liquid state, which is a process of condensation that releases heat, and its internal pressure is generally very high ； In the evaporator, the refrigerant changes from a liquid state to a gas state; this is an evaporation process that absorbs heat, and its internal pressure is generally low. In summary, the condenser is one of the main heat exchange devices in refrigeration systems. Its function is to cool and condense the superheated vapor of refrigerant discharged from the compressor back into liquid refrigerant, while releasing heat into the cooling medium. Common cooling media are: water and air. The evaporator is a device in a refrigeration system used for heat exchange between the refrigerant and a low-temperature heat source, and it is also one of the main heat exchange devices in a refrigeration unit. In the evaporator, the refrigerant liquid vaporizes at low pressure and low temperature, absorbing heat from the medium being cooled; it then becomes a dry saturated gas or superheated steam of the refrigerant under low pressure and low temperature, thereby generating and delivering cold energy within the refrigeration system. The evaporator is located between the throttle valve and the return gas pipe of the refrigeration machine, or between the supply and return gas pipes of the vapor-liquid separation equipment, and is installed in the cold rooms or areas that need to be cooled or frozen.

A condenser is used to cool a medium and cause it to liquefy, releasing heat in the process； An evaporator is a device in which a medium absorbs heat and vaporizes, thereby taking in heat from the surroundings.

Adjust the internal pressure ratio so that it matches the external pressure ratio; in other words, this is to prevent under-compression and over-compression!

A condenser is a heat exchange device that allows the high-pressure, superheated refrigerant vapor discharged by the compressor to release heat, thereby condensing it into a liquid or subcooled liquid. An evaporator is a device that cools the liquid refrigerant after throttling, allowing it to absorb heat and vaporize thereby achieving a cooling effect. As air passes through the evaporator, heat is absorbed by the refrigerant inside it, thereby cooling the air or reducing its humidity.

Both condensers and evaporators are types of heat exchangers. Heat exchange refers to a device that enables heat transfer between two or more fluids at different temperatures; it is therefore also known as a heat exchange unit. Therefore, although there are various structural designs for condensers and evaporators, their working principle is the same: they are all devices that exchange heat between the refrigerant and the external medium flowing over their surface, in other words, they are all types of heat exchangers. In terms of the factors affecting heat transfer, condensers and evaporators are similar; their heat transfer capacity is related to the heat exchange area, the temperature difference for heat transfer, and the heat transfer coefficient. However, the working principles of the condenser and the evaporator are different; the condenser is used to cool a medium and cause it to liquefy, releasing heat in the process ； An evaporator is a device in which the medium absorbs heat and vaporizes, thereby taking in heat from the surroundings; in other words, the refrigerant changes from a gaseous state to a liquid state, which is a process of condensation that releases heat, and its internal pressure is generally very high ； In the evaporator, the refrigerant changes from a liquid state to a gas state; this is an evaporation process that absorbs heat, and its internal pressure is generally low. In summary, the condenser is one of the main heat exchange devices in refrigeration systems. Its function is to cool and condense the superheated vapor of refrigerant discharged from the compressor back into liquid refrigerant, while releasing heat into the cooling medium. Common cooling media are: water and air.

Equipment for transferring cold outside. Condenser: The refrigerant vapor transfers the heat absorbed from the evaporator under high pressure, as well as the heat generated by compression work, to the cooling medium, where it condenses into a liquid at a higher temperature (condensation temperature). It is a device that releases heat.

Condenser: Reduces the temperature of the high-temperature, high-pressure gaseous refrigerant, converting it into a high-pressure refrigerant state； Evaporator: Converts low-temperature, high-pressure liquid refrigerant into low-pressure gaseous refrigerant