Experimental study of a reversible ventilation – heat pump system with a ceramic regenerator

Abstract

Mechanical supply-exhaust ventilation systems are increasingly required in newly constructed residential buildings, yet their higher primary energy consumption remains a key challenge, particularly given the growing demands of energy efficiency and unchanged fresh air requirements. Existing solutions based on recuperators achieve heat recovery efficiencies of 40−70%, whereas regenerative systems can exceed 90%, but their performance under real operating conditions and integration with heat pump technology has not been sufficiently investigated. This study presents an experimental analysis of a compact ventilation unit, dedicated to classrooms, operating in reversible mode with a rotary regenerator and an integrated R290 (propane) air-to-air heat pump. Measurements were conducted across an outdoor temperature range from 0.6°C to 8.6°C. The regenerator-only mode achieved heat recovery efficiency exceeding 90% throughout the entire tested temperature range. When the R290 heat pump was activated to sustain operation during periods of lower outdoor temperatures without an auxiliary heat source, the system yielded COP values between 3.70 and 4.31, substantially higher than 2.0−2.5 values typically reported for conventional air-to-air heat pumps. These results demonstrate that the proposed integration of regenerative heat recovery with a dedicated R290 heat pump constitutes a technically viable and energy-efficient solution for both heating and ventilation needs.