MANY MINDEDSouth Korean heat pump retrofit adds ventilator exhaust air to boost cooling efficiency
South Korean researchers from Hanyang University and the Korea Institute of Civil Engineering and Building Technology developed a retrofit solution for residential air-source heat pumps. By channeling exhaust air from energy recovery ventilators through direct evaporative cooling, the system boosted its coefficient of performance (COP) by 7.3–15.2% under hot and humid conditions—specifically at outdoor temperatures of 30–33°C and 60–70% relative humidity. This approach reduced the outdoor-unit inlet air temperature by up to 6.4°C and lowered compressor work by 13.8% compared to standard heat pumps. The design requires only adding an evaporative cooler to existing units and connecting to ventilation exhaust ducts, enabling cost-effective upgrades without full system replacement.
The innovation directly addresses cooling costs in hot climates by leveraging free exhaust air to reduce the heat load on refrigerants. For households in regions with high temperatures and humidity, this retrofit could lower electricity use for heating and cooling—critical for energy access in areas where grid power is expensive or unreliable. By improving heat pump efficiency without new infrastructure, it makes cooling more affordable for low-income communities where air conditioning is often unaffordable.
What to watch: The gains are confined to specific humidity and temperature ranges (60–70% RH, 30–33°C). The system also relies on a 100 m³/h airflow rate that wasn’t physically installed during testing, and retrofitting requires additional components beyond existing heat pumps. Real-world scalability depends on local climate conditions and the availability of ventilation systems. The research, published in the Journal of Building Engineering, shows promise for hot-humid regions but needs field validation in diverse settings.
Source: pv magazine