Refrigeration
Refrigeration
Embedded Files
Refrigeration is a thermodynamic process that involves the removal of heat from a low-temperature region (or substance) and its rejection to a high-temperature region, thereby maintaining the cooled space at a temperature lower than the surroundings.
According to the Second Law of Thermodynamics, this heat transfer from low to high temperature cannot occur spontaneously and requires an external work input (usually supplied by a compressor or pump).
Example:
In a domestic refrigerator, heat is absorbed from the food compartment (low-temperature region) and rejected to the room air (high-temperature region) using a vapor-compression refrigeration cycle.
Similarly, an air conditioner extracts heat from an indoor space and releases it outdoors.
Graphical definition
Graphical definition
Removing heat (QL) from a low‑temperature space and rejecting it as (QH) to a higher‑temperature reservoir by supplying external work (Win).
Refrigeration Effect
Refrigeration Effect
The Refrigeration Effect (RE) is the amount of heat absorbed from the low-temperature region (refrigerated space) to produce the cooling effect.
It is generally expressed in kJ/kg of refrigerant.
Mathematically:
Example:
In a domestic refrigerator, the evaporator absorbs heat from the food compartment, which constitutes the refrigeration effect.
Refrigeration Capacity
Refrigeration Capacity
The Refrigeration Capacity (also known as Cooling Capacity) is the rate at which heat is removed from the refrigerated space.
It is expressed in kW or TR (Tons of Refrigeration).
Mathematically:
Example:
An air conditioner with a refrigeration capacity of 3.5 kW can remove heat at the rate of 3.5 kJ per second from the room.
Unit of Refrigeration
Unit of Refrigeration
The commonly used unit of refrigeration is Ton of Refrigeration (TR).
1 TR is defined as the rate of heat removal required to freeze 1 ton (1000 kg) of water at 0°C in 24 hours.
In SI units:
Illustrative Example:
A domestic refrigerator removes heat from the food compartment (low-temperature region) and rejects it to the surrounding room air (high-temperature region) using a vapor-compression refrigeration cycle.
Similarly, an air conditioner extracts heat from an indoor space and releases it outdoors, maintaining a comfortable indoor temperature
Page updated
Report abuse