Decentralised ventilation and air-conditioning systems consist of a below-roof unit and an above-roof unit. To start with, the below-roof unit is inserted into the roof frame from above. The unit needs to jut out into the hall at least as far as the upper edge of the air outlet. If this isn’t possible – say, owing to crane girders being set up – the units can be fitted further into the roof using a plinth in the shape of a truncated pyramid.
The above-roof unit is then positioned on top of the bottom unit and they are screwed together. Depending on the exact location, it should take around 30 minutes to install both of these units.
In order for the unit parts to be lifted straight up from the loading area to the hall roof quickly, it is ideal to have them delivered on a flatbed truck. If they do arrive on an enclosed form of transport, a forklift truck with long forks will need to be available for sideways unloading.
Installation work should not begin until all of the unit parts have been delivered. This is because the above- and below-roof units each come with specifically adjusted instrumentation and control equipment and they therefore need to be installed together properly.
If a crane with a large reach and high hook is needed to install the units (owing to the size of the hall) and/or if the crane needs to be used multiple times, it can be expected that the process will take a very long time.
In this case, using a helicopter at the installation stage instead may save time and money. In fact, if everything is prepared properly, the installation time could be just six minutes per unit (two lifts).
When decentralised ventilation systems are installed in a hall, several units supply the area in question. Units operating under the same conditions (operating times, setpoint temperature and so on) are grouped into control zones.
State-of-the-art instrumentation and control equipment allows individual units to be controlled separately (hydraulic individual switching) and in zones (zone controller). In the latter case, the zone controller manages the operating modes, schedules, parameters, lockouts and fault messages. A separate operating and input module allocates the units to the plant structure and sets the operating modes and programs.
The overall system is made up of decentralised units as well as instrumentation and control components set up for the specific plant, and should be used as one “unit”. This system reliably guarantees fully automatic and energy-efficient operation of all components in line with the specific requirements. This even applies when the plant is integrated into an existing building control system with decentralised instrumentation and control components, e.g. via a Modbus BACnet interface.