text: Since evaporation occurs when heat is absorbed , and condensation occurs when heat is released , air conditioners use a compressor to cause pressure changes between two compartments , and actively condense and pump a refrigerant around .
simplified: Since evaporation occurs when heat is absorbed , and condensation occurs when heat is released , air conditioners are designed to use a compressor to cause pressure changes between two compartments , and actively pump a refrigerant around .