Performance analysis of a novel organic fluid filled regenerative heat exchanger used heat recovery ventilation (OHeX-HRV) system

Abstract

In this study, a novel organic fluid-filled regenerative heat exchanger used heat recovery ventilation (OHeX-HRV) system was designed. Five organic-based fluids (R11, R123, R245fa, n-Pentane and Isopentane) were selected by considering operating conditions. Indoor air exit temperature, outdoor air inlet temperature and recovered heat by regenerative heat exchanger were analysed depending on varying airspeeds (V-air = 1,2,3 m/s) and outdoor environment temperatures (0-40 degrees C). As a result of the study, it was observed that recovered heat decreased as the outdoor environment temperature approaches from 0 degrees C to comfort temperature of indoor environment (24 degrees C). In contrast, the amount of heat recovered increased as the outdoor environment temperature diverges from indoor comfort temperature. The amount of recovered energy increased directly related to increasing airspeed thanks to increasing air mass flow. Among selected working fluids, n-Pentane (10.812 kJ/kg) and Isopentane (10.716 kJ/kg) used OHeX-HRV system resulted in the highest energy recovery per unit air mass. From n-Pentane used OHeX-HRV system, hourly energy recovery was calculated as 426.22 kJ/h when airspeed was 3 m/s. After comprehensive analyses, it was concluded that n-Pentane which has also superiority in terms of safety and environmental impact showed the best heat recovering performance when used in proposed OHeX-HRV system.