A review on energy recovery techniques and applications of air conditioning condensate

Building energy consumption accounts for over 30% of global energy consumption, with heating, ventilation, and air conditioning systems accounting for 40–60% of building energy consumption. During the operation of the air conditioning system, condensate with low temperature and high water quality will be generated. However, condensate is typically discharged as waste, resulting in significant energy waste. It is crucial to explore different technologies and applications for effectively utilizing the energy in condensate. This review introduces energy recovery techniques, applications in different air conditioning systems, and the use of condensate recovery in various applications. The use of condensate for cooling air conditioning components can increase the COP by approximately 5–30%. When used for cooling tower heat dissipation, it can reduce the total energy consumption of the system by approximately 3.6%. Split and portable air conditioning typically produce less than 10 liters of condensate per day, resulting in lower economic benefits and a cost recovery cycle generally exceeding 5 years. Although the daily condensate production of central air conditioning systems can reach up to 100 liters, the equipment innovation and the high initial investment for condensate recovery are still significant challenges for further research.