Development of an Intelligent Condenser Fan Control System with Water-Assisted Discharge Line Cooling

Abstract

split-type air conditioners are the highest energy-consuming appliances in residential buildings, particularly due to the compressor and the condenser fan within the condensing unit. Concurrently, air conditioning systems continuously generate condensate water from the evaporator unit. This condensate water maintains a low average temperature of 15–20°C and is typically discarded. This research proposes an approach to enhance energy efficiency by utilizing this waste condensate water for water-assisted cooling of the compressor discharge line prior to entering the condenser, integrated with an automatic condenser fan speed control system to reduce the overall electrical energy consumption.The developed system operates by using the evaporator condensate water to lower the temperature of the compressor discharge line through heat absorption. Temperature sensors detect the temperature differences to transmit signals to a controller, which subsequently modulates and decreases the condenser fan speed corresponding to the real-time water-assisted cooling efficiency. Based on experimental testing on a 9,000 BTU wall-mounted split-type air conditioner installed in an actual residential building, the power consumption of the condensing unit was 980 Watts before system installation. Following the implementation of the compressor discharge line cooling device combined with the fan speed control system, the power consumption decreased to 930 Watts. This demonstrates that the system can achieve an electrical energy reduction of up to 5%. In addition to energy-saving efficiency, the continuous reduction of the thermal load substantially extends the operational lifespan of both the compressor and the air conditioning system.