X-CUBE ROOMAIR-B-ZAB+SEK

Functional description

Decentralised supply and extract air units with secondary air addition for room ventilation. They cover the cooling and heating load in accordance with the technical data. An EC centrifugal fan takes in the outdoor air and this then flows through the maintenance-free and mechanical self-powered type VFL volume flow limiter, which is pre-set at the factory to the maximum volume flow rate. This ensures maximum limitation of the outdoor air flow rate to a pre-set value for all façade positive pressure situations without an electrical external power supply. The air then flows through the motorised shut-off damper, the self-powered non-return damper and the outdoor air filter. The self-powered non-return dampers in the outdoor air intake and exhaust air outlet prevent the return flow of the conditioned air or undesired airflow directions. Then the outdoor air flows through the cross-flow heat recovery unit, which can be bypassed in energetically sensible operating situations and for unit protection. If necessary, the air is heated or cooled by the heat exchanger before it is supplied into the room as a displacement flow. To increase the heating and cooling capacity, indoor air is added to the supply air by the secondary air fan, thus increasing the supply air flow rate. The extract air first passes through the outdoor air filter, then flows through the heat recovery unit, the extract air fan, the non-return damper and the motorised shut-off damper before it is discharged to the outside as exhaust air. If the indoor air quality is sufficient, the FSL-CONTROL III control system switches to energy-efficient secondary air mode by closing the outdoor air dampers. The control system compares the room air quality setpoint value to the actual value measured by the CO2 sensor and switches automatically between outdoor air and secondary air operation. In case of a power failure, the outdoor air and exhaust air dampers are closed to ensure fire protection, frost protection and to avoid draughts. This is ensured by a capacitor in each actuator. Near the external wall, the supply air is discharged into the room with a medium velocity between 0.5 and 0.8 m/s. Due to the induction effect, the supply air velocity is rapidly reduced so that, in cooling mode, the supply air displaces the room air over the entire floor area. Near heat sources such as people or equipment, a lift current is formed by natural convection, so that the air is exchanged primarily in these areas.