Air conditioners, like any other system, cannot be more than 100% efficient according to the laws of thermodynamics. The efficiency of an air conditioner is determined by the ratio of the useful output (cooling effect) to the input energy (typically electrical energy).
The term "more than 100% efficient" is sometimes used colloquially or in marketing to describe certain features of air conditioning systems, but it is not a reflection of their actual efficiency. Here are a few reasons why this terminology may be used:
Coefficient of Performance (COP): The efficiency of an air conditioner is often expressed in terms of its Coefficient of Performance (COP). COP is defined as the ratio of the cooling output (measured in British Thermal Units, or BTUs, for example) to the electrical input (measured in watts). If an air conditioner has a COP greater than 1, it means that it produces more cooling output per unit of electrical input. However, this does not imply that the system violates the laws of thermodynamics; it simply indicates that it can move more heat energy than the electrical energy it consumes.
Heat Transfer: Air conditioners do not create cooling; they transfer heat from one place (indoors) to another (outdoors). The cooling effect experienced indoors is the result of removing heat from the indoor air and releasing it outside. So, when an air conditioner is described as more than 100% efficient, it may be referring to the ratio of the cooling effect produced to the energy consumed, without considering the energy used to remove the heat outdoors.
Energy Savings: Newer air conditioning systems may be marketed as "more than 100% efficient" when compared to older, less efficient models. This indicates that they provide the same cooling effect while using less energy. These improvements are achieved through technological advancements, such as more efficient compressors, better insulation, improved airflow management, or variable-speed motors. The increased efficiency is relative to older models, not an actual efficiency value above 100%.
In summary, when air conditioners are referred to as more than 100% efficient, it is typically a way of describing their ability to transfer heat energy efficiently or their improved performance compared to older models. However, it's important to understand that their actual efficiency remains bound by the laws of thermodynamics, and they cannot exceed 100% efficiency.