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🔋college physics i – introduction review

Absorption Refrigerator

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

An absorption refrigerator is a type of refrigeration system that uses heat energy, rather than mechanical energy, to provide the cooling effect. It operates on the principle of evaporation and condensation of a refrigerant to remove heat from the refrigerated space and transfer it to the environment.

5 Must Know Facts For Your Next Test

  1. Absorption refrigerators use a heat source, such as natural gas, propane, or solar energy, to drive the refrigeration cycle instead of a compressor.
  2. The refrigeration cycle in an absorption refrigerator involves the evaporation of a refrigerant, the absorption of the refrigerant vapor by a absorbent solution, and the subsequent regeneration of the refrigerant.
  3. Absorption refrigerators are commonly used in recreational vehicles, boats, and off-grid applications where a conventional compressor-based refrigerator may not be practical.
  4. Compared to compressor-based refrigerators, absorption refrigerators are generally quieter, have fewer moving parts, and can operate on a variety of heat sources.
  5. The efficiency of an absorption refrigerator is typically lower than that of a compressor-based refrigerator, but the simplicity and versatility of the design make it a viable option in certain applications.

Review Questions

  • Explain the basic principle of operation of an absorption refrigerator.
    • An absorption refrigerator operates on the principle of evaporation and condensation of a refrigerant. The refrigerant, such as ammonia or water, is evaporated in the evaporator, absorbing heat from the refrigerated space. The refrigerant vapor is then absorbed by a solution, typically water or a water-lithium bromide mixture, which is then heated to regenerate the refrigerant. The refrigerant is then condensed, releasing heat to the environment, and the cycle repeats. This heat-driven cycle allows for the removal of heat from the refrigerated space without the use of a mechanical compressor.
  • Discuss the advantages and disadvantages of absorption refrigerators compared to compressor-based refrigerators.
    • Absorption refrigerators have several advantages over compressor-based refrigerators. They are generally quieter, have fewer moving parts, and can operate on a variety of heat sources, including natural gas, propane, or solar energy, making them suitable for applications where a conventional power source may not be available. However, absorption refrigerators typically have lower efficiency compared to compressor-based refrigerators, and the initial cost can be higher. The simplicity and versatility of the design, along with the lack of a compressor, make absorption refrigerators a viable option in certain applications, such as recreational vehicles, boats, and off-grid settings.
  • Evaluate the environmental impact of absorption refrigerators and their role in the context of thermodynamics and heat pump applications.
    • Absorption refrigerators can have a lower environmental impact compared to compressor-based refrigerators, as they do not rely on the use of electricity or ozone-depleting refrigerants. The heat-driven cycle of an absorption refrigerator aligns with the principles of thermodynamics, as it involves the transfer of heat from a lower-temperature region (the refrigerated space) to a higher-temperature region (the environment). This process is similar to the operation of a heat pump, which can be used for both heating and cooling applications. From a thermodynamic perspective, the efficiency of an absorption refrigerator is typically lower than a compressor-based system, but the use of renewable or waste heat sources can make it a more sustainable option in certain applications, particularly in off-grid or remote locations where access to electricity may be limited.