In conventional induction units, the achievable cooling capacity is closely linked to the induction ratio and therefore on the primary air volume. It also determines the resulting flow configuration. However, the required fresh air supply rate in the building depends on the number of occupants, while the cooling capacity is primarily a function of the solar input. For the purposes of energy efficiency, it makes sense to decouple these functions.
LTG induction units from the SmartFlow system solve this problem by offering up to three different operating and flow modes that act depending on the actually required outside air volume and cooling capacity:
- Normal operation uses so-called combined mixed/displacement air flow, which combines the benefits of mixed air ventilation close to the induction unit with those of displacement air ventilation in the frequented area. To achieve this, an injector in the ventilation unit blows the cold air flow diagonally upwards at low speed so that it mixes fully with the room air over a short distance. This reduces the air velocity and the temperature differences between the layers of air to a comfortable level, and the air penetrates deep into the room at floor level. The target temperature can be achieved even at low air velocities. This so-called mixed/displacement air ventilation also helps counter the formation of temperature layers in the room and prevents unpleasantly cold layers at foot level. The intensive mixing of the cold supplied air and the warm air in the area of the facade results in a considerable increase in comfort. In normal operation, noise emissions are under 28 dB(A), making the system barely audible. The mixed/displacement air ventilation concept was developed by LTG’s engineers in Stuttgart and has been incorporated into VDI Guideline 3804 on air conditioning and ventilation technology for office buildings.
- When the room occupancy level is high (for example in conference rooms or other heavily frequented rooms), the mixed/displacement air ventilation is reinforced by a displacement air outlet for additional primary ventilation to ensure that adequate ventilation and air conditioning continue to be guaranteed.
- When fast and intensive air conditioning is required, there is the so-called “boost mode” which takes the form of a type of pulsed ventilation for temporary use. In this case, an additional row of nozzles is opened and all the unit’s flow channels are activated. The unit operates at full load and generates layers of air from mixed air and displacement air ventilation, thus again permitting a high level of comfort. In this way, for example, rooms that have been left empty over chilly weekends can rapidly be heated to the desired temperature on Monday mornings.
