Absorptiojäähdyttimet

Absorptiojäähdyttimet, also known as absorption chillers, are refrigeration devices that use a thermal power source instead of a mechanical compressor to produce cooling. Unlike vapor-compression refrigeration systems, absorption chillers rely on a thermodynamic absorption cycle that involves a refrigerant and an absorbent. Common working fluids are water and lithium bromide, or ammonia and water.

The cycle begins with the refrigerant evaporating at low pressure, absorbing heat from the space to be cooled. This low-pressure vapor then enters an absorber, where it is absorbed by the absorbent solution. The absorbent then pumps the refrigerant-rich solution to a generator, where it is heated by an external energy source, such as waste heat, steam, or natural gas. This heating process drives the refrigerant out of the absorbent as a high-pressure vapor. The refrigerant vapor then condenses into a liquid and flows through an expansion valve, where its pressure and temperature are reduced before returning to the evaporator to complete the cycle.

Absorption chillers are particularly advantageous in situations where waste heat is readily available or where electricity costs are high. They can be more energy-efficient than conventional chillers when powered by sources like solar thermal energy or the exhaust heat from industrial processes. However, their initial cost can be higher, and they typically have a lower coefficient of performance (COP) compared to vapor-compression systems when powered solely by electricity. They are often used in large commercial buildings, industrial facilities, and district cooling systems.