Chiller for absorption in an HVAC system

The absorption chiller plays a crucial role in an HVAC system. A device known as an absorption chiller creates hot or cold water using a heat source, a refrigerant, and an absorbent. Along with vapour compression water chillers and electric chillers, absorption cooling systems are used in various applications when it comes to chillers. In a vacuum, absorption chillers create chilled water for air conditioning and technological processes.

the fundamental elements of vapour absorption chillers

Simple absorption chillers (single stage) are made up of the following components:

  • Generators
  • Condensers
  • Evaporator
  • Pump for solution, 
  • absorber, 
  • heat exchanger, and 
  • refrigeration
Absorption Chiller Operation Principle

1. The generator's role in the absorption chiller

In indirect fired absorption chillers, flue gases, hot water, or operational steam are used to heat weak solution in the absorption chiller generator. While natural gas, diesel, or kerosene oil are used to power direct fired absorption chillers. The solution becomes concentrated after heating in the generator, and high-temperature refrigerant vapours are created. High temperature and pressure refrigerant vapours leave the chiller after the generating process and move to the condenser. Through a heat exchanger, a strong solution is introduced to the absorber to exchange heat with a weak solution.

2. The Condenser's Role in an Absorption Chiller

cycle of vapour absorption

Cooling water causes the refrigerant vapour from the generator to condense in the condenser. Condensation is a constant pressure process where cooling water absorbs heat from refrigerant (water). This method of refrigerant heat transfer to the atmosphere. After exchanging heat with air in cooling towers of the same HVAC system, cooling water in water-cooled chillers is recycled.

3. Evaporator's role in an absorption chiller

Condenser to evaporator flow of refrigerant. The refrigerant in this compartment of the absorption chiller vaporises by absorbing heat from the chilled water. A refrigerant pump is used to move refrigerant from the evaporator refrigerant pan over the evaporator tubes. The refrigerant is evaporated by the refrigerant flow over the evaporator tubes, generating the refrigeration effect. The refrigerant absorbs heat from the cooled water passing through the tubes and then evaporates to generate vapour. Evaporation occurs in this way at constant pressure when refrigerant absorbs latent heat from chiller water. Here in the absorber, the chiller absorbs. Cooled chilled water is returned to the customer's system.

4. Absorber in Absorption Chiller Function


Produced refrigerant vapour enters the absorber and is absorbed by the absorber's strong solution. Strong solution is diluted in this manner by absorbing refrigerant vapour in the absorber. Water used for cooling carries the heat produced to the atmosphere.

5. The absorption chiller's HVAC Solution Pump's Function

By way of a solution pump, a generator receives this weak solution to concentrate. Pumps are parts of absorption cooling systems that need electricity to function. Through a heat exchanger, weak solution from the absorber is fed into the generator. The refrigeration effect is replicated when the operation is continued.

Must Read: Electric (Compression) Chillers vs. Absorption Chillers

Try this HVAC quiz on vapour compression cycles or absorption chillers.







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