Study of a prototype of an advanced mechanical ventilation system with heat recovery integrated by heat pump

•New heat recovery system which works according different arrangements is presented.•A double PI controller properly adjusts the supply air temperature.•A new energy efficiency index is introduced to regulate the passive recovery.•High COPs are obtained even though the supply air temperature modulations.•The switching through different arrangements needs more deepening. In this study, a mechanical ventilation system with heat recovery integrated by heat pump was analysed. The recovery unit can works according different arrangements: passive plus thermodynamic recovery, only passive or active recovery and freecooling. The study was carried out to evaluate the energy performances of the system during the control of temperature in winter season. Tests were performed at different temperature values of simulated outdoor air To (−5°C, 0°C, 5°C and 10°C) and a fixed (reference) indoor simulated temperature (20°C). Each trial was performed with a ventilation flow rate of 535m3/h. The coefficient of performance of the overall system (COPs) is 9.50 at 0°C, 8.86 at 5°C and 6.62 at 10°C respectively. At −5°C the compressor behaved as an on-off type. This is due to a safety mechanism for the evaporator defrost. This behavior suggests the existence of a temperature value at which is preferable to switch from the static plus thermodynamic operation mode to another arrangement and vice-versa. Also a comparison with other prototypes found in literature and with a common commercial system was made. It results that SIVeMeC has higher energy performances in a wide range of temperature than other system analysed.