Proposal of an eco-friendly high-performance air-conditioning system part 2. Application of evapo-transpiration condenser to residential air-conditioning system

• Experiment applying evapo-transpiration condenser to air conditioner has been done.
• 5–10 °C reduction in hourly-average condenser temperature is achieved.
• 30%–40% energy saving is recorded at outdoor temperature lower than 31 °C.
• Space in front of new outdoor-unit is more comfortable than that of existing unit.

Improving performance of existing air-conditioning system and minimizing its environmental effect are requested from global environmental issues. A new air-conditioning system using evapo-transpiration condenser has been proposed. Evapo-transpiration condenser is a condenser that uses transpiration by keeping condenser surface wet and water evaporation enhancing heat-transfer rate. In this paper, a prototype of the new system is tested and compared with the existing system in summer weather of Japan. Hourly-average condenser-temperature is achieved to be 5–10 °C reduction compared to that of the air-cooled condenser. Without any optimization in system operation, up to more than 30% hourly integral power consumption is saved at ambient temperature below 31 °C from this prototype. Besides, temperature of outlet-air from outdoor-unit is nearly the same as ambient temperature, while its relative humidity is slightly higher. Special maintenance is not necessary for the new evapo-transpiration condenser.