Experimental Evaluation of Heat Recovery Ventilators in Hot Climates

This study investigates the thermal, economic, and environmental performance of heat recovery ventilators (HRVs) in hot climates, which has not been thoroughly investigated because standards and applications to date have focused primarily on cold climates. Experimental testing was conducted at airflow rates of 200–350 m 3 /h and outdoor air temperatures of 30–45 °C, representing typical summer conditions. HRV thermal performance was evaluated by measuring airflow rates and temperatures and then determining the heat transfer rates between the two air streams. Effectiveness increased by 3.9% when the supply inlet temperature increased from 30 to 45 °C, but decreased by 9.3% when airflow increased from 200 to 350 m 3 /h. The overall heat transfer coefficient remained nearly constant with increasing supply temperature but increased by approximately 37% as airflow increased. The highest recovery efficiency ratio (RER), defined as the ratio of supply air pre-cooling capacity to HRV power consumption, was 26.6 Btu/W.hr at 300 m 3 /h and 45 °C. Economic analysis based on the reduction in ventilation cooling load yielded payback periods ranging from 2.7 to 13.3 years. Annual CO 2 emission reductions ranged from 151 to 776 kg/year per HRV unit, demonstrating the environmental benefits of HRV systems in hot climates.